No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Anti-HIV activity of olive leaf extract (OLE) and modulation of host cell gene expression by HIV-1 infection and OLE treatment
Abstract
We investigated the antiviral activity of olive leaf extract (OLE) preparations standardized by liquid chromatography-coupled mass spectrometry (LC-MS) against HIV-1 infection and replication. We find that OLE inhibits acute infection and cell-to-cell transmission of HIV-1 as assayed by syncytia formation using uninfected MT2 cells co-cultured with HIV-1-infected H9 T lymphocytes. OLE also inhibits HIV-1 replication as assayed by p24 expression in infected H9 cells. These anti-HIV effects of OLE are dose dependent, with EC(50)s of around 0.2 microg/ml. In the effective dose range, no cytotoxicity on uninfected target cells was detected. The therapeutic index of OLE is above 5000. To identify viral and host targets for OLE, we characterized gene expression profiles associated with HIV-1 infection and OLE treatment using cDNA microarrays. HIV-1 infection modulates the expression patterns of cellular genes involved in apoptosis, stress, cytokine, protein kinase C, and hedgehog signaling. HIV-1 infection up-regulates the expression of the heat-shock proteins hsp27 and hsp90, the DNA damage inducible transcript 1 gadd45, the p53-binding protein mdm2, and the hedgehog signal protein patched 1, while it down-regulates the expression of the anti-apoptotic BCL2-associated X protein Bax. Treatment with OLE reverses many of these HIV-1 infection-associated changes. Treatment of HIV-1-infected cells with OLE also up-regulates the expression of the apoptosis inhibitor proteins IAP1 and 2, as well as the calcium and protein kinase C pathway signaling molecules IL-2, IL-2Ralpha, and ornithine decarboxylase ODC1.
... Olive leaf extracts have attracted a special interest due to their phenolic acids composition with therapeutic effects (Sahin et al., 2017). Olive extracts have different classes of biophenols including secoiridoids (oleuropein), flavonoids (luteolin 4-O-glucoside, apigenin 7-O-glucoside, luteolin 7-O-glucoside, rutin), phenolic acids, phenolic alcohols (tyrosol and hydroxytyrosol), and secoiridoids (oleuropein) (Lee-Huang, Zhang, Lin Huang, Chang, & Huang, 2003). Oleuropein is the most important bioactive compound in the olive leaf extract, having antiviral, antioxidative, antimicrobial (Lee-Huang et al., 2003,) ardioprotective, antiatherogenic, antiinflammatory, and antihypertensive properties (Ranalli et al., 2006) and improve lipid metabolism in order to relieve obesity problems (Erbay & Icier, 2009). ...
... Olive extracts have different classes of biophenols including secoiridoids (oleuropein), flavonoids (luteolin 4-O-glucoside, apigenin 7-O-glucoside, luteolin 7-O-glucoside, rutin), phenolic acids, phenolic alcohols (tyrosol and hydroxytyrosol), and secoiridoids (oleuropein) (Lee-Huang, Zhang, Lin Huang, Chang, & Huang, 2003). Oleuropein is the most important bioactive compound in the olive leaf extract, having antiviral, antioxidative, antimicrobial (Lee-Huang et al., 2003,) ardioprotective, antiatherogenic, antiinflammatory, and antihypertensive properties (Ranalli et al., 2006) and improve lipid metabolism in order to relieve obesity problems (Erbay & Icier, 2009). In addition, a synergistic effect of all biophenols present in the extract has been reported, and it is recommended the use of the extract without isolating to obtain the health benefit. ...
... It is important to underscore the novelty of the present study, as it reveals the antibacterial activities of olive twig extracts-previously underexplored parts of the olive tree compared to the leaves. According to prior research, phenolic compounds not only exhibit significant synergistic effects against B. cereus [57,60] but can also modulate inflammatory and macrophage responses, potentially providing activity against pathogens [61]. ...
Biofilms represent complex three-dimensional microbial communities that can harbor strains highly resistant to antimicrobial agents. These structures, which form on both biotic and abiotic surfaces, are associated with food spoilage and increased complications in hospitalized patients. Consequently, there is significant interest in developing novel biofilm and infection control strategies, particularly those focusing on natural molecules with dual antimicrobial and antibiofilm properties. In this study, olive tree twigs from three varieties of Olea europea chemlal (CH), Azeradj (AZ), and wild-type Olea europaea sylvestris (W) were collected from the Kabylia region in Algeria. The samples underwent systematic extraction and were evaluated for their antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, antimicrobial properties via disk diffusion assay, minimum inhibitory concentration (MIC), and antibiofilm capabilities. Results demonstrated that olive tree twig extracts exhibited substantial antioxidant activity and significant antibacterial and antibiofilm potential. The antioxidant activity, measured through DPPH radical scavenging, showed IC50 values ranging from 38.12 ± 1.52 µg/mL to 148.7 ± 1.23 µg/mL. When tested against six pathogenic bacterial strains, including both ATCC reference strains and milk isolates, the MIC values ranged from 1.18 mg/mL to 4.71 mg/mL. Notably, sub-inhibitory concentrations significantly reduced biofilm formation across most tested strains, with inhibition rates varying from 21% to 90.43%. The effectiveness of biofilm inhibition was dependent on the bacterial strain, olive tree variety, and extract concentration used. Statistical analysis confirmed the significance of these results (p < 0.05). Given the demonstrated antioxidant, antibacterial, and antibiofilm properties of these olive tree twig extracts, they show promise for further development as surface disinfectants and potential applications in food safety and infection control. Additional research is warranted to fully characterize their mechanisms of action and optimize their practical applications.
... Predominantly olive fruits and olive oil, but also olive leaves, have been used in traditional medicine to treat cancer, hypertension, arrhythmia and intestinal muscle spasms (Khayyal et al. 2002;Özcan and Matthäus2017) and are thought to be the source of several phytochemicals which have antioxidant, anti-in ammatory, antibacterial (Venditti et al. 2013;Borges et al. 2020), antiviral (Lee-Huang et al. 2003;Micol et al. 2005) and anti-tumor properties (Hamdi et al. 2005;Abaza et al. 2007). ...
Two wild olive subspecies fixed in this research: Olea europaea subsp. europaea var. sylvestris and Olea europaea subsp. laperrinei despite its ecological value, the chemical composition of subsp. laperrinei oil remains unknown, the samples were harvested from the different geographical area. Gas Chromatography-Mass Spectrometry(GC-MS) and Gas Chromatography-flame-ionization detection (GC-FID) analysis of subsp europaea var. sylvestris allowed the identification of 29 compounds oil with Nonanal (11.82%), theaspiranea A (9.81%), 3-hexen-1-ol,benzoate(9.31%) as a major constituents , while the subspecies of the Saharan region were resultedthe identification of 31 compounds where α-pinene (16%) , β-Ocimene (12.82%), dl-Limonene(8.20%) was the main components . The results of the disc diffusion method showed that the two volatile oils have efficient antibacterial activity but, subsp. laperrinei essential oil has a higher range of inhibition, in which P. aeruginosa and B. subtilis showed extreme sensitivity, while the K. pneumoniae bacterium shows great resistance to the two essential oils.
... Te extracted leaves of Olea europaea have drawn attention since they have phenolic compounds that are linked to various pharmacological activities [14]. Several in vitro and in vivo studies have demonstrated wide range of health benefts of the extracted Olea europaea leaves, such as cytotoxic activity against human breast cancer cells [15], an antiproliferative efect on leukemia cells [16,17], an antiarrhythmic efect [18], a hypotensive efect [19], an anti-HIV efect [20], and an antimalaria efect [21]. Te wide range of these pharmacological activities is mostly linked to oleuropein and its bioactive byproduct, hydroxytyrosol, which comprises the major active compound in olive leaves [22]. ...
Olea europaea leaf extract (OELE) has potential health bene4ts and protects against cytotoxicity. *is study investigated
the possible ameliorative e6ect of OELE on cisplatin-induced nephrotoxicity in rats. Methods. Rats were assigned into
six groups; two groups received 150 mg/kg or 300 mg/kg of OELE, one group received a single dose of cisplatin (6 mg/kg) IP on the
4rst day of the experiment, two groups received a single dose of cisplatin 150 mg/kg or 300 mg/kg of OELE on the 4rst day then
starting from the 4fth day for 10 consecutive days, and one group acted as a control. Results and Conclusion. *e 4ndings showed
that cisplatin-induced nephrotoxicity was evidenced by a signi4cant increase in serum creatinine blood urea nitrogen (BUN) and
a signi4cant decrease in estimated creatinine clearance and potassium level, which corresponded with the alterations in the
histopathology of the renal tissue. OELE signi4cantly ameliorated the nephrotoxic e6ects of cisplatin as dose-dependent.
... This is mostly due to the increased availability of phytochemicals in higher concentrations, which are used to boost the value of foods and pharmaceuticals. Olive leaves have been used in traditional medicine in some Mediterranean regions for some time, and they are known to be a good source of phenolic compounds that possess antioxidant, antibacterial, antifungal, antiviral, antiatherogenic, cardioprotective, antihypertensive, anti-inflammatory, hypocholesterolemic, and hypoglycemic activities [2][3][4][5][6][7][8][9][10][11][12]. Ceratonia siliqua is one of the most useful native Mediterranean trees and is regarded as a significant part of the vegetation for both economic and environmental reasons. ...
Background
Olive (Olea europaea L.) and carob (Ceratonia siliqua L.), which contain considerable amounts of phenolic compounds, are the most important nutritional and therapeutic plants in the Mediterranean basin.
Objectives
The goal of this work is to revalue carob and olive leaves as key sources of polyphenols, hence increasing the value of waste goods.
Objective
The goal of this work is to revalue carob and olive leaves as key sources of polyphenols, hence increasing the value of waste goods.
Methods
In this study, aqueous acetone or ethanol (80% v/v) extracts of olive (O. europaea L. cultivar aimel) and carob (C. siliqua L.) leaves from Algeria were evaluated for phenolic content, and the extracts were characterized by reverse-phase high-performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-ESI-MS).
Discussion/Results
The total phenolic content of olive and carob leaf extracts ranged from 5.6 to 23 mg GAE/g. The use of HPLC-ESI-MS to investigate phenolics revealed that the extracts included a variety of phenolic compounds, including 23 compounds in olive leaf extracts and 17 compounds in carob leaf extracts. In olive and carob, the major phenolic components are oleuropein and myricetin rhamnoside, respectively.
Conclusion
According to our findings, olea europaea and Ceratonia siliqua appear to be rich suppliers of natural chemicals. These plants have a lot of potential in terms of medications and functional foods.
Conclusion
Olea europaea and Ceratonia siliqua appear to be rich suppliers of natural chemicals, according to our findings. This plant has a lot of potential in terms of medications and functional foods.
... Coming up to coronavirus infection, it is now well known that the virus targets the host cells ACE 2 receptor, the same which is activated in HIV-1 infections. That is why some successful treatments of HIV-1 and SARS-2 infections were made with olive leaves extracts (Lee-Huang et al., 2003;and Boss et al., 2016). ...
... 25,26 Although its antiviral mechanism of action is not fully understood, several studies have been conducted on the antiviral effects of olive leaf extract. [25][26][27][28][29] Active immunity results when exposure to a disease organism triggers the immune system to produce antibodies specific to that disease through natural immunity or vaccine-induced immunity. ...
Objective: During the Coronavirus Disease-2019 (COVID-19) pandemic, in addition to the current measures, the healthy immune system plays an essential role and various natural agents have been recommended to boost innate immunity. The aim of this study was to investigate any association between the potential immunomodulatory activity and drinking olive leaf tea (OLT) in the COVID-19 pandemic. Design: The study was conducted among the workers in a tractor factory where OLT was served in routine. Drinking at least one cup of OLT per day for a minimum of 1 month was the inclusion criteria used in the study. The workers who had a history of vaccination and COVID-19 were excluded from the study, and lymphocyte subsets, interleukin (IL)-2, IFN-γ, COVID-19-specific IgM and IgG levels were analyzed in all the participants to determine the asymptomatic individuals among the participants and compare the immunological parameters. Results: The study was conducted among 336 workers, 183 of them were OLT drinkers and 153 were OLT nondrinkers. The results showed higher values of CD3-/CD16/56 (natural killer [NK]) cells, CD3+/CD16/56 (natural killer T [NKT]) cells, total NK (NK+NKT) cells, and serum IFN-γ, and IL-2 levels in OLT drinkers compared to the nondrinkers. Although all the OLT drinkers and nondrinkers included in the study reported no history of COVID-19, specific COVID-19 IgG levels were found positive in 60% of OLT drinkers and 38% OLT nondrinkers. Conclusions: Peripheral NK and NKT cell values and IL-2 and IFN-γ secretion levels were found higher in the OLT drinking group. There were positive correlations between the OLT drinking frequency and NK cell counts. Moreover, the number of individuals who had "asymptomatic" COVID-19 infection was higher in the OLT drinking group than in the nondrinking cohort. Clinical Trail: The trial has been registered in the ClinicalTrials.gov database (CTR NCT05222347).
... The biological activities of OLE are mainly derived from these compounds [13,2] . In the present of study revealed presence of plasmids in untreated strain, but absence of plasmids in the treated which was the physical confirmation of plasmid curing of bacteria effected by the aqueous olive leaves extract, was confirmed with Sylvia [14] . And Fabiani [15] who showed that olive oil phenols have potent anti DNA damage effect. ...
Effective control of pathogenic bacteria key to the prevention and treatment of disease, therefore many plants are used in traditional medicine as treatment for bacterial infections. In the present study (7) microbial pathogens as (Staphylococcus aureus, Salmonella typhimurium, Enterococcus faecalis, Klebsiella pneumoniae, Pseudomonas aeruginosa, Listeria monocytogenes and Streptococcus mutans) isolated in the laboratory of veterinary medicine collage of Baghdad university. The present results show that aqueous olive leaves extract have potential antibacterial activities against some of bacterial strains, then select Staphylococcus aureus and Streptococcus mutans which are more sensitive to different concentrations (0.5, 1, 3, 6%) than other bacterial strain for the ability of hot aqueous extract of olive leaves. Plasmid profiling is among the methods used to determine and characterize aqueous olive leaves extract traits in bacteria. To induce the cleavage in cells, DNA fragmentation of microorganisms used. In addition to those treated with antibiotic (kanamycin and ampicillin) for comparing the results, the DNA fragments were observed using agarose gel electrophoresis. This phenomenon was tested for the ability of extract of olive leafs to induce the cleavage in cells (DNA fragmentation). Pathogenic bacteria Staphylococcus aureus and Streptococcus mutans were exposed to at (0.5, 1, 3 and 6%) concentration and incubated for 24 hours. Staphylococcus aureus and Streptococcus mutans when applied with the extracts olive leaves showed a marked DNA fragmentation, and no fragmentation was observed in untreated cells. The results confirmed that the extracts of olive leaves can interact with DNA of the bacteria. This may explain the inhibitory action on DNA synthesis. Hence, the hot aqueous extract of olive leaves possessed antibacterial potential against these microorganisms. While kanamycin and ampicillin not posses such activity.
... After extraction, insoluble material was removed using Whatman No. 1 filter paper. The filtrates were then concentrated at 50°C to yield a dark brown solid extract, with references to the powdered samples; the yields of the OLE were 3.59 g, and extracts were stored in the refrigerator for rat supplementation (Lee-Huang et al. 2003;Al-Attar and Abu Zeid 2013;Wulandari et al. 2016). ...
Lead acetate (PbAc) is one of the toxic metals in the environment which causes many effects on different organs of the body. And due to the importance of the olive tree, with its healthy and protective elements against many diseases, the leaf extract of this tree was chosen in our study. Therefore, the aim of this study was to investigate the role of olive leaf (Olea europea L.) extract (OLE) against PbAc-induced sperm toxicity, sex hormone changes, oxidative stress, and histopathological changes in rats. Twenty male Wistar rats were divided into four groups (group 1, as control; group 2, OLE; group 3, PbAc; group 4, PbAc+OLE). In the PbAc group, the body weight, testis and epididymis weights, sexual hormones, sperm characteristics, GR, GPx, GST, GSH, SOD, and CAT were significantly decreased, and the sperm abnormality and TBARS level were significant increase when compared with control and OLE groups. Also, numerous damages to testicular tissue were observed in the PbAc group when compared to the control group, while the treatment with OLE in the fourth group led to improvement of sex hormones, semen characteristics, oxidative stress, and testicular tissue damage caused by PbAc. It can be concluded that OLE has a protective and ameliorative effects against PbAc-induced oxidative stress, apoptosis and alterations in testicular tissue, and sperm quality in rats.
... Also, it had been found that Olive leaves inhibits acute infection and cell-tocell transmission of HIV-1 and additionally inhibits HIV-1 replication. [10]. The major active elements in olive leaf is oleuropein (see Fig.1 a) and its derivatives, like hydroxytyrosol and tyrosol, additionally as cafeic acid, p-coumaric acid, vanillic acid, vanillin, luteolin, diosmetin, rutin, luteolin-7glucoside, apigenin-7-glucoside, and diosmetin-7- [11]. ...
Olive tree (Olea Europea L.) is one of the most important crops in the Mediterranean countries. The global olive oil industry annually generates many tons of olive leaves as waste. The present study aims at a valorisation of Algerian olive leaves harvested from the region of Bouira for therapeutic use. In order to evaluate the biological effects of the wild olive tree, chemical characterization tests of the leaves were carried out in the Natural Substances Laboratory of Saidal group according to their validated protocols drawn from the French pharmacopoeia. A phytochemical screening has been realized and whose purpose is to refer to the extraction, screening and identification of the medicinally active substances in the plant. Different extractions have been carried out in several solvents in order to extract bioactive molecules from the leaves using several solvents. Subsequently, a pharmacological characterization has been completed by determining the following: antioxidant activity of the extracts was evaluated in vitro by the DPPH method, anti-inflammatory activity was studied in vivo by induction of carrageenan oedema; the antibacterial activity was achieved by the agar medium diffusion method. Finally, we formulated an anti-inflammatory and antibacterial ointments based on the results obtained.
Interest in the olive leaf and its chemical constituents has recently been increasing. Its benefits, however, have been known for centuries, and it has been traditionally used to prevent and treat diseases. The main constituent of the olive leaves is oleuropeine one of iridoide monoterpenes, which is thought to be responsible for pharmacological effects. Furthermore, the olive leaves contain triterpenes including oleanolic and maslinic acid, flavonoides (luteolin, apigenine, rutin...), and chalcones (olivin, olivin-diglucoside). Its chemical content makes olive leaf one of the most potent natural antioxidant. Olive leaf is used to enhance the immune system, as an antimicrobial and in heart disease. Folk medicine uses also include hypertonia, arteriosclerosis, rheumatism, gout, diabetes mellitus, and fever. Recently, experimental animal studies have demonstrated hypoglycemic, hypotensive, antiarrhythmic, and vasodilator effects, as well as spasmolytic effect on the intestinal smooth muscle. Antibacterial, antiviral and antiinflammatory activity were also confirmed. The beneficial properties of olive leaf are further enhanced by the bioavailability of its polyphenolic constituents, which are readily absorbed through the gastrointestinal tract, resulting in significant levels in the circulation. Clinical studies to confirm experimental results are needed
Natural compounds that have been used with several traditional methods for years may exhibit one or more antibacterial, antifungal, antiviral, and antioxidant properties. Today, as the value of antiviral natural compounds is increasingly recognized, the number of studies on their isolation, extraction, purification, and characterization are accelerating. However, the number of studies on producing antiviral biomaterials and textile-based healthcare products are still limited. This chapter provides a systematic overview of this topic. Following a discussion of the classification and properties of biopolymers, the sources and mechanisms of action of antiviral natural compounds are described. The literature on biopolymer-based biomaterials and textile products containing antiviral natural compounds has been compiled and presented. Since there are a limited number of studies on the subject in the literature, production methods of biomaterials and textile-based healthcare products are given in order to shed light on future studies. The chapter is completed by emphasizing the potential of these healthcare products.
There is still a great global need for efficient treatments for the management of SARS-CoV-2 illness notwithstanding the availability and efficacy of COVID-19 vaccinations. Olive leaf is an herbal remedy with a potential antiviral activity that could improve the recovery of COVID-19 patients. In this work, the olive leaves major metabolites were screened in silico for their activity against SARS-CoV-2 by molecular docking on several viral targets such as methyl transferase, helicase, Plpro, Mpro, and RdRp. The results of in silico docking study showed that olive leaves phytoconstituents exhibited strong potential antiviral activity against SARS-CoV-2 selected targets. Verbacoside demonstrated a strong inhibition against methyl transferase, helicase, Plpro, Mpro, and RdRp (docking scores = -17.2, -20, -18.2, -19.8, and -21.7 kcal/mol.) respectively. Oleuropein inhibited 5rmm, Mpro, and RdRp (docking scores = -15, -16.6 and -18.6 kcal/mol., respectively) respectively. Apigenin-7-O-glucoside exhibited activity against methyl transferase and RdRp (docking score = -16.1 and -19.4 kcal/mol., respectively) while Luteolin-7-O-glucoside inhibited Plpro and RdRp (docking score = -15.2 and -20 kcal/mol., respectively). The in vitro antiviral assay was carried out on standardized olive leaf extract (SOLE) containing 20% oleuropein and IC50 was calculated. The results revealed that 20% SOLE demonstrated a moderate antiviral activity against SARS-CoV-2 with IC50 of 118.3 μg /mL. Accordingly, olive leaf could be a potential herbal therapy against SARS-CoV-2 but more in vivo and clinical investigations are recommended.
Olea europaea L. (Oleaceae), is rich in phenolic content and has powerful antioxidant and antidiabetic activity. However, there are no medicinal products prepared due to this feature. Therefore, this study aims to characterize an O. europaea extract with strong antioxidant and antidiabetic properties and to prepare nanoformulations containing this extract. To determine the activities of the extracts prepared from the leaves of the plant, DPPH• and ABTS•+ scavenging, Fe+3 reducing activity, α-amylase, and α-glucosidase inhibition assays were performed. The oleuropein content of the absolute ethanol extract with the highest activity was analysed by HPLC. The characterized extract was loaded into liposomes and chitosan coated liposomes, and the long-term sustainability of their activity was investigated. The encapsulation efficiency was 65.2% for the liposome and 66.8% for the chitosan-coated liposome formulation. The amounts of the extracts released from the formulations were evaluated to exhibit antioxidant and antidiabetic activity.
The constant emergence of severe health threats, such as antibacterial resistance or highly transmissible viruses, necessitates the investigation of novel therapeutic approaches for discovering and developing new antimicrobials, which will be critical in combating resistance and ensuring available options. Due to the richness and structural variety of natural compounds, techniques centered on obtaining novel active principles from natural sources have yielded promising results. This review describes natural products and extracts from Latin America with antimicrobial activity against multidrug-resistant strains, as well as classes and subclasses of plant secondary metabolites with antimicrobial activity and the structures of promising compounds for combating drug-resistant pathogenic microbes. The main mechanisms of action of the plant antimicrobial compounds found in medicinal plants are discussed, and extracts of plants with activity against pathogenic fungi and antiviral properties and their possible mechanisms of action are also summarized. For example, the secondary metabolites obtained from Isatis indigotica that show activity against SARS-CoV are aloe-emodin, β-sitosterol, hesperetin, indigo, and sinigrin. The structures of the plant antimicrobial compounds found in medicinal plants from Latin America are discussed. Most relevant studies, reviewed in the present work, have focused on evaluating different types of extracts with several classes and subclasses of secondary metabolites with antimicrobial activity. More studies on structure–activity relationships are needed.
Leaves of the Olea europaea L. species are frequently utilized in both folk and modern medicine.In nowadays are strongly valuable for their beneficial effects to treat a multitude of bacterial and inflammation-type diseases, two wild olive subspecies fixed in this research: the widespread Mediterranean Olea europaea subsp. europaea var. sylvestris and the endemic Olea europaea subsp. laperrinei from Saharan region, Despite its ecological value, the chemical composition of subsp. laperrinei oil remains unknown, the samples were harvested from the different geographical area. Gas Chromatography-Mass Spectrometry(GC-MS) and Gas Chromatography-flame-ionization detection (GC-FID) analysis of subsp europaea var. sylvestris allowed the identification of 29 compounds oil with Nonanal (11.82%), Theaspiranea A (9.81%), 3-hexen-1-ol,benzoate(9.31%), β-damascenone (6.87%), α-pinene (6.32%), Farnesol (6.10%) as a major constituents, while the subspecies of the Saharan region were resultedthe identification of 31 compounds where α-pinene (16%), β-Ocimene (12.82%), dl-Limonene(8.20%), Nonanal (8.18%), was the main components .The Monoterpene hydrocarbons represented the most abundant class in the two essential oils samples. The results of the disc diffusion method showed that the two volatile oils have efficient antibacterial activity but, subsp. laperrinei essential oil has a higher range of inhibition, in which P. aeruginosa and B. subtilis showed extreme sensitivity, while the K. pneumoniae bacterium shows great resistance to the two essential oils. These results demonstrated the medicinal value of olive leaves, as well as the impact of climate on the volatiles produced.
Indian traditional medicinal systems are one of the oldest therapeutic systems in the world. Medicinal and aromatic plants play a dominant role in Indian traditional medicinal systems. Traditionally, many medicinal plants are used in India for their therapeutic relevance so much so that they have acquired a significant role in Indian religion as well. Many of these plants have proven antiviral effects. This review documents up-to-date information about many such medicinal herbs used in India which have got pharmacological significance in fighting viral infections. These plants surely have the potential to provide protection against Covid-19. The review presents a list of such plants along with their chemical ingredients and possible modes of action against the respective viral diseases. All information has been obtained by consulting the databases of Scopus, PubMed, Science Direct, Elsevier, Springer and relevant research papers and reports on COVID-19. The cited medicinal plants are used extensively in India as herbal remedies. The use of these plants is validated in light of research papers citing their ethnobotanical uses, important active principles and modes of action of the of medicinally important natural products. The plants listed have great potential to fight COVID-19 and other viral infections. Many of these are immunity boosters providing strength to the body to control the onset of diseases.
The present study aims to assess the antioxidant and antiviral effectiveness of leaf extracts obtained from Olea europaea L. var. sativa and Olea europaea L. var. sylvestris. The total antioxidant activity was determined via both an ammonium phosphomolybdate assay and a nitric oxide radical inhibition assay. Both extracts showed reducing abilities in an in vitro system and in human HeLa cells. Indeed, after oxidative stress induction, we found that exposition to olive leaf extracts protects human HeLa cells from lipid peroxidation and increases the concentration of enzyme antioxidants such as catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase. Additionally, OESA treatment affects viral DNA accumulation more than OESY, probably due to the exclusive oleuropein content. In fact, subtoxic concentrations of oleuropein inhibit HSV-1 replication, stimulating the phosphorylation of PKR, c-FOS, and c-JUN proteins. These results provide new knowledge about the potential health benefits and mechanisms of action of oleuropein and oleuropein-rich extracts.
Natural deep eutectic solvents (NADES) composed of choline chloride with maltose (CMA), glycerol (CGL), citric (CCA) and lactic acid (CLA) combined with microwave (MAE), ultrasound (UAE), homogenate (HAE) and high hydrostatic pressure (HHPAE)-assisted extraction methods were applied to recover and compare olive leaf phenolic compounds. The resultant extracts were evaluated for their total phenol content (TPC), phenolic profile and antioxidant activity and compared with those of water and ethanol:water 70% v/v extracts. HAE was proven to be the most efficient method for the recovery of olive leaf phenolic compounds. The highest TPC (55.12 ± 1.08 mg GAE/g d.w.) was found in CCA extracts after HAE at 60 °C and 12,000 rpm, and the maximum antioxidant activity (3.32 ± 0.39 g d.w./g DPPH) was found in CGL extracts after UAE at 60 °C for 30 min. The TPCs of ethanol extracts were found to be higher than those of NADES extracts in most cases. The predominant phenolic compounds in the extracts were oleuropein, hydrohytyrosol and rutin.
Medicinal plants are always acceptable for their activity towards different disease targets as they contain various extractable chemical constituents and bioactive metabolites. Plant products have been showing their unexpected activities towards different point of our life since the very first day of civilization. During metabolism process, plants produce different chemical compounds including different secondary metabolites that are not involved in the direct growth or development of the plant but in protection of the plant from different outside as well as inside enemies. Those secondary metabolites such as polyphenols, alkaloids, flavonoids, tannins, sapogenins are having different biological activities towards different diseases conditions in human body. Hundreds of secondary metabolites from different plants have been tested preclinically as well as clinically and gave excellent action against different disease such as inflammation, diabetic, carcinogenesis, depression, cytotoxicity, hepatotoxicity, microbial infection including viral infections as HIV. This chapter is mainly focused on different activities of different secondary metabolites and their mechanism of actions in different stages of the life cycle of HIV and its infection in human body including some reported compounds with potent activity. Papaverine, Apocynin, Taxifolin, Mangiferin, Genomycin I including Calanolide A, Suksdorfin, Bevirimat, etc. are well-known compounds from different natural sources that showed very potent activities in different conditions of HIV infection.
Olive oil production is a significant source of economic profit for Mediterranean nations, accounting for around 98 percent of global output. Olive oil usage has increased dramatically in recent years, owing to its organoleptic characteristics and rising knowledge of its health advantages. The culture of olive trees and the manufacture of industrial and table olive oil produces enormous volumes of solid waste and dark liquid effluents, involving olive leaves, pomace, and olive oil mill wastewaters. These by-products cause an economic issue for manufacturers and pose major environmental concerns. As a result, partial reuse, like other agronomical production wastes, is a goal to be achieved. Because these by-products are high in bioactive chemicals, which, if isolated, might denote components with significant added value for the food, cosmetic, and nutraceutical sectors, indeed, they include significant amounts of beneficial organic acids, carbohydrates, proteins, fibers, and phenolic materials, which are distributed differently between the various wastes depending on the olive oil production method and table olive agronomical techniques. However, the extraction and recovery of bioactive materials from chosen by-products is a significant problem of their reasonable value, and rigorous detection and quantification are required. The primary aims of this review in this context are to outline the vital bioactive chemicals in olive by-products, evaluate the main developments in extraction, purification, and identification, and study their uses in food packaging systems and safety problems.
Objective: Complementary and alternative medicine (CAM) has an increasing usage in the last decades throughout the world. Herbal medicine, the most preferred CAM, is used in the treatment of various disorders by approximately eighty percent of the world's population. In this study, it was aimed to determine the antiviral activity and wound healing potential of a special herbal oil blend prepared from Olea europaea, Nigella sativa and Rosmarinus officinalis that has been used for centuries in Middle and East Anatolia. Materials and Methods: The nontoxic concentration of herbal blend was determined by MTS assay. This concentration was investigated for its wound healing potential using in vitro scratch assay. A scratch was made on cultured keratinocyte cell layer and the herbal blend was added to medium. Pictures of cells were taken at different time points. The antiviral activity was determined using Adenovirus type 5 and Poliovirus type 1. Virus titer was calculated by Spearman-Karber method. Results: The nontoxic concentration of the blend was found to show statistically higher wound healing rate in compare to control group at the end of 12, 24 and 36 hours. According to antiviral efficacy test, four log of reduction in virus titer was seen, which meant that the mixture was quite effective against the viruses used in the study. Conclusion: The study shows that the special herbal blend speed up wound healing rate and it also has antiviral activity.
There is currently a worldwide consensus and recognition of the undoubted health benefits of the so-called Mediterranean diet, with its intake being associated with a lower risk of mortality. The most important characteristics of this type of diet are based on the consumption of significant amounts of fruit, vegetables, legumes, and nuts, which provide, in addition to some active ingredients, fiber and a proportion of vegetable protein, together with extra virgin olive oil (EVOO) as the main sources of vegetable fat. Fish and meat from poultry and other small farm animals are the main sources of protein. One of the main components, as already mentioned, is EVOO, which is rich in monounsaturated fatty acids and to a lesser extent in polyunsaturated fatty acids. The intake of this type of nutrient also provides an important set of phytochemicals whose health potential is widely spread and agreed upon. These phytochemicals include significant amounts of anthocyanins, stilbenes, flavonoids, phenolic acids, and terpenes of varying complexities. Therefore, the inclusion in the diet of this type of molecules, with a proven healthy effect, provides an unquestionable preventive and/or curative activity on an important group of pathologies related to cardiovascular, infectious, and cancerous diseases, as well as those related to the metabolic syndrome. The aim of this review is therefore to shed light on the nutraceutical role of two of the main phytochemicals present in Olea europaea fruit and leaf extracts, polyphenols, and triterpenes, on healthy animal growth. Their immunomodulatory, anti-infective, antioxidant, anti-aging, and anti-carcinogenic capabilities show them to be potential nutraceuticals, providing healthy growth.
The latest study was performed to investigate the ethno pharmacological potential of ethnobotanical significant plant, Olea ferruginea Royle that is a member of the Oleaceae family. The stem of this plant and leaf powders were macerated in different (polar and non-polar) solvents. The phytochemical study showed the occurrence of saponins, alkaloids, anthraquinonines, flavonoids, minimizing sugars, cardiac glycosides, tannins and terpenoids in reasonable quantities in Olea ferruginea, as verified by Fourier Transform Infrared (FT-IR) analysis. Based on the findings of the current research, the traditional use of this targeted plant of the Oleaceae family as food, fodder, feed, and medicinal seems acceptable and therefore justifiable.
The moderate electrical field (MEF) process was used to reduce the process time (t) of oleuropein extraction from olive leaves. MEF process was performed with methanol-water (4:1 v/v) with sine wave-SN and square wave-SQ at 30 V/cm with different frequencies (1, 1000, and 2000 Hz). The conventional extraction (CE) method was performed for 8 h in methanol-water (4:1 v/v) mixture at 40 °C. The effects of MEF conditions on t, effective electrical conductivity (EEC), cell disintegration (Zc) and extraction performance coefficient (EPC) were determined. SN provided desired extraction yield in a shorter time than SQ (p < 0.05). The necessary extraction time for target extraction yield (21.6 ± 1.0 mg Oleuropein/g dm) increased as the frequency decreased (p < 0.05). SN resulted in higher Zc values compared to SQ (p < 0.05). EPC of MEF was higher than CE (p < 0.05). It is concluded extractability of the oleuropein at any given extraction time could be improved by MEF compared to CE.
Citation: Ben-Amor, I.; Gargouri, B.; Attia, H.; Tlili, K.; Kallel, I.; Musarra-Pizzo, M.; Sciortino, M.T.; Pennisi, R. In Vitro Anti-Epstein Barr Virus Activity of Olea europaea L. Leaf Extracts. Plants 2021, 10, 2445. https:// Abstract: Olea europaea L. var. sativa (OESA) preparations are widely used in traditional medicine in the Mediterranean region to prevent and treat different diseases. In this research, olive extracts derived from the leaves of the OESA tree have been screened for antioxidant activity by two methods: the DPPH free radical scavenging assay (DPPH) and the Ferric reducing antioxidant power (FRAP) assay. The DPPH assay showed that OESA possesses a stronger antioxidant activity (84%) at 1 mg/mL while the FRAP method showed a strong metal ion chelating activity (90%) at 1 mg/mL. The low IC 50 values, obtained by two different methods, implies that OESA has a noticeable effect on scavenging free radicals comparable to standards. During EBV infection, the free radicals increased triggering lipid oxidation. Therefore, the monitoring of the secondary lipid peroxidation products was done by measuring malonaldehyde (MDA) and conjugated dienes (DC). The simultaneous treatment of Raji cells with OESA and TPA, as an inductorof the lytic cycle, generated a significant decrease in MDA levels and DC (p < 0.05). Besides, Raji cells simultaneously exposed to TPA and OESA exhibited a percentage of EBV-positive fluorescence cells lower than TPA treated cells (**** p < 0.0001). This suggests that OESA treatment has a protective effect against EBV lytic cycle induction.
Viral infections are being managed therapeutically through available antiviral regimens with unsatisfactory clinical outcomes. The refractory viral infections resistant to available antiviral drugs are alarming threats and a serious health concern. For viral hepatitis, the interferon and vaccine therapies solely are not ultimate solutions due to recurrence of hepatitis C virus. Owing to the growing incidences of viral infections and especially of resistant viral strains, the available therapeutic modalities need to be improved, complemented with the discovery of novel antiviral agents to combat refractory viral infections. It is widely accepted that medicinal plant heritage is nature gifted, precious, and fueled with the valuable resources for treatment of metabolic and infectious disorders. The aims of this review are to assemble the facts and to conclude the therapeutic potential of medicinal plants in the eradication and management of various viral diseases such as influenza, human immunodeficiency virus (HIV), herpes simplex virus (HSV), hepatitis, and coxsackievirus infections, which have been proven in diverse clinical studies. The articles, published in the English language since 1982 to 2017, were included from Web of Science, Cochrane Library, AMED, CISCOM, EMBASE, MEDLINE, Scopus, and PubMed by using relevant keywords including plants possessing antiviral activity, the antiviral effects of plants, and plants used in viral disorders. The scientific literature mainly focusing on plant extracts and herbal products with therapeutic efficacies against experimental models of influenza, HIV, HSV, hepatitis, and coxsackievirus were included in the study. Pure compounds possessing antiviral activity were excluded, and plants possessing activity against viruses other than viruses in inclusion criteria were excluded. Hundreds of plant extracts with antiviral effect were recognized. However, the data from only 36 families investigated through in vitro and in vivo studies met the inclusion criteria of this review. The inferences from scientific literature review, focusing on potential therapeutic consequences of medicinal plants on experimental models of HIV, HSV, influenza, hepatitis, and coxsackievirus have ascertained the curative antiviral potential of plants. Fifty-four medicinal plants belonging to 36 different families having antiviral potential were documented. Out of 54 plants, 27 individually belong to particular plant families. On the basis of the work of several independent research groups, the therapeutic potential of medicinal plants against listed common viral diseases in the region has been proclaimed. In this context, the herbal formulations as alternative medicine may contribute to the eradication of complicated viral infection significantly. The current review consolidates the data of the various medicinal plants, those are Sambucus nigra, Caesalpinia pulcherrima, and Hypericum connatum, holding promising specific antiviral activities scientifically proven through studies on experimental animal models. Consequently, the original research addressing the development of novel nutraceuticals based on listed medicinal plants is highly recommended for the management of viral disorders.
The diversity in Jordan’s flora due to its geographical areas make is well noted in the scientific literature. The challenge of disease and death caused by infectious diseases like viruses and bacteria, and as infectious diseases evolve and pathogens develop resistance to existing pharmaceuticals, the search for new novel leads, possibly with different modes of action, against bacterial and viral diseases has intensified in recent years. The intent of this review is to provide prevalent information on the antibacterial and antiviral potential in medicinal plants in Jordan, mode of action, type of viruses and bacteria, and phytochemical contents. It has been demonstrated by several studies presented in this review that medicinal plants in Jordan are rich in phytochemicals and possess antiviral and antibacterial properties.
Olive tree (Olea europea L.) leaves represent around 10% of the total weight of olives arriving at any given mill, which are generally discarded, causing economic and environmental issues. However, these are rich sources of natural bioactive compounds (i.e., polyphenols), which have health-promoting potential. Thus, the valorization of olive leaves by recovering and reusing their components should be a must for food sustainability and circular economy. This review provides an insight into the principal polyphenols present in olive leaves, together with agronomic variables influencing their content. It also summarizes the recent advances in the application of novel extraction technologies that have shown promising extraction efficacy, reducing the volume of extraction solvent and saving time and cost. Moreover, potential industrial uses and international patents filed in the pharmaceutic, food, and cosmetic sectors are discussed.
The wastes generated during the olive oil extraction process, even if presenting a negative impact for the environment, contain several bioactive compounds that have considerable health benefits. After suitable extraction and purification, these compounds can be used as food antioxidants or as active ingredients in nutraceutical and cosmetic products due to their interesting technological and pharmaceutical properties. The aim of this review, after presenting general applications of the different types of wastes generated from this industry, is to focus on the olive pomace produced by the two‐phase system and to explore the challenging applications of the main individual compounds present in this waste. Hydroxytyrosol, tyrosol, oleuropein, oleuropein aglycone, and verbascoside are the most abundant bioactive compounds present in olive pomace. Besides their antioxidant activity, these compounds also demonstrated other biological properties such as antimicrobial, anticancer, or anti‐inflammatory, thus being used in formulations to produce pharmaceutical and cosmetic products or in the fortification of food. Nevertheless, it is mandatory to involve both industries and researchers to create strategies to valorize these byproducts while maintaining environmental sustainability.
As olive leaves constitute the main by-product of the olive oil industry with important environmental and economic impact, there is an increasing demand for its valorization. In the present work, we report the development and application of immobilized enzyme batch bioreactors for the chemo-enzymatic treatment of an aqueous Olea europaea leaf extract rich in oleuropein to produce an extract enriched in hydroxytyrosol and other oleuropein hydrolysis products. To this end, a robust biocatalyst was developed through the immobilization of β-glucosidase on chitosan-coated magnetic beads which exhibited high hydrolytic stability after 240 h of incubation at 37 °C. The biocatalyst was successfully used in both a rotating bed-reactor and a stir-tank reactor for the modification of the olive leaf extract leading to high conversion yields of oleuropein (exceeding 90%), while an up to 2.5 times enrichment in hydroxytyrosol was achieved. Over 20 phenolic compounds (from different classes of phytochemicals such as flavonoids, secoiridoids, and their derivatives) were identified, in the extract before and after its modification through various chromatographic and spectroscopic techniques. Finally, the biological activity of both extracts was evaluated. Compared to the non-modified extract, the modified one demonstrated 20% higher antioxidant activity, seven-fold higher antibacterial activity, and enhanced cytotoxicity against leiomyosarcoma cells.
Secoiridoids play a key role in determining health benefits related to a regular consumption of extra-virgin olive oil (EVOO), in which they are generated from precursors of the same class naturally occurring in drupes and leaves of the olive (Olea europaea L.) plant. Here, reversed-phase liquid chromatography coupled to electrospray ionization and Fourier-transform single/tandem mass spectrometry (RPLC-ESI-FTMS and MS/MS) was employed for a structural elucidation of those precursors. The presence of three isoforms in both matrices was assessed for oleuropein ([M-H]− ion with m/z 539.1770) and was emphasized, for the first time, also for ligstroside (m/z 523.1821) and for the demethylated counterparts of the two compounds (m/z 525.1614 and 509.1665, respectively). However, only the prevailing isoform included an exocyclic double bond between carbon atoms C8 and C9, typical of oleuropein and ligstroside; the remaining, less abundant, isoforms included a C=C bond between C8 and C10. The same structural difference was also observed between secoiridoids named elenolic acid glucoside and secoxyloganin (m/z 403.1246). This study strengthens the hypothesis that secoiridoids including a C8=C10 bond, recently recognized as relevant species in EVOO extracts, arise mainly from specific enzymatic/chemical transformations occurring on major oleuropein/ligstroside-like precursors during EVOO production, rather than from precursors having that structural feature.
Simple Summary
Olives are cultivated mostly in the Mediterranean as well as in Asia Minor, Korea, Japan, and China. Olive oil is currently used as a food ingredient in human diet, and its consumption is gradually expanding in various countries. Therefore, olive cultivation and oil extraction produce a significant amount of byproducts; providing these byproducts as feed to livestock has been attempted for a long period. Economic, environmental, and nutritional considerations make the use of olive byproducts efficient and cost-effective as feed for ruminants. Among the olive byproducts, olive leaves (OLs) contain higher levels of polyphenols than olive fruits, and have a very high feed value. In this study, it was confirmed that methane production decreased during 12 h of in vitro fermentation, and the number of fat-utilizing microorganisms increased in the 5% OLs group. OLs were found to show antioxidant and antimicrobial activity. Moreover, the proportion of cellulose-degrading bacteria, Fibrobacter succinogenes, Ruminococcus albus, and Ruminococcus flavefaciens increased in the 5% OLs group at 12 h and decreased at 24 h. Olive leaves are believed to be very useful as feed additives and supplements for ruminants.
Abstract
We evaluated whether olive leaves (OLs) are effective as feed additives and supplements for ruminants and the potential methane reduction effects during in vitro fermentation. Two Hanwoo cows (460 ± 20 kg) equipped with cannula were fed Timothy hay and corn-based feed 3% of the body weight at a ratio of 6:4 (8:30 a.m. and 5:00 p.m.). Ruminal fluid from the cows was collected and mixed before morning feeding. In vitro batch fermentation was monitored after 12 and 24 h of incubation at 39 °C, and OLs were used as supplements to achieve the concentration of 5% in the basal diet. At 12 h of fermentation, methane production decreased in the 5% OLs group compared to that in the control group, but not at 24 h. The proportion of cellulose-degrading bacteria, Fibrobacter succinogenes, Ruminococcus albus, and Ruminococcus flavefaciens, tended to increase in the 5% OLs group at 12 h. The amount of ammonia produced was the same as the polymerase chain reaction result for Prevotella ruminicola. At 12 h, the proportion of Prevotella ruminicola was significantly higher in the 5% OLs group. OLs may be used incorporated with protein byproducts or other methane-reducing agents in animal feed.
Owing to the richness of bioactive compounds, Olea europea leaf extracts exhibit a range of health effects. The present research evaluated the antibacterial and antiviral effect of leaf extracts obtained from Olea europea L. var. sativa (OESA) and Olea europea var. sylvestris (OESY) from Tunisia. LC-DAD-ESI-MS analysis allowed the identification of different compounds that contributed to the observed biological properties. Both OESA and OESY were active against Gram-positive bacteria (MIC values between 7.81 and 15.61 μg/mL and between 15.61 and 31.25 μg/mL against Staphylococcus aureus ATCC 6538 for OESY and OESA, respectively). The antiviral activity against the herpes simplex type 1 (HSV-1) was assessed on Vero cells. The results of cell viability indicated that Olea europea leaf extracts were not toxic to cultured Vero cells. The half maximal cytotoxic concentration (CC50) values for OESA and OESY were 0.2 mg/mL and 0.82 mg/mL, respectively. Furthermore, both a plaque reduction assay and viral entry assay were used to demonstrate the antiviral activity. In conclusion, Olea europea leaf extracts demonstrated a bacteriostatic effect, as well as remarkable antiviral activity, which could provide an alternative treatment against resistant strains.
In recent years, a remarkable increase in olive oil consumption has occurred worldwide, favoured by its organoleptic properties and the growing awareness of its health benefits. Currently, olive oil production represents an important economic income for Mediterranean countries, where roughly 98% of the world production is located. Both the cultivation of olive trees and the production of industrial and table olive oil generate huge amounts of solid wastes and dark liquid effluents, including olive leaves and pomace and olive oil mill wastewaters. Besides representing an economic problem for producers, these by-products also pose serious environmental concerns, thus their partial reuse, like that of all agronomical production residues, represents a goal to pursue. This aspect is particularly important since the cited by-products are rich in bioactive compounds, which, once extracted, may represent ingredients with remarkable added value for food, cosmetic and nutraceutical industries. Indeed, they contain considerable amounts of valuable organic acids, carbohydrates, proteins, fibers, and above all, phenolic compounds, that are variably distributed among the different wastes, depending on the employed production process of olive oils and table olives and agronomical practices. Yet, extraction and recovery of bioactive components from selected by-products constitute a critical issue for their rational valorization and detailed identification and quantification are mandatory. The most used analytical methods adopted to identify and quantify bioactive compounds in olive oil by-products are based on the coupling between gas- (GC) or liquid chromatography (LC) and mass spectrometry (MS), with MS being the most useful and successful detection tool for providing structural information. Without derivatization, LC-MS with electrospray (ESI) or atmospheric pressure chemical (APCI) ionization sources has become one of the most relevant and versatile instrumental platforms for identifying phenolic bioactive compounds. In this review, the major LC-MS accomplishments reported in the literature over the last two decades to investigate olive oil processing by-products, specifically olive leaves and pomace and olive oil mill wastewaters, are described, focusing on phenolics and related compounds.
Hydroxytyrosol (4-(2-hydroxyethyl)-1,2-benzenediol) is the most known bioactive compound from the plant Olea europaea (olive tree). To date, few biocatalysis processes allowing efficient production of hydroxytyrosol from potential substrates including, tyrosol (2-(4-hydroxy) phenyl ethanol) and tyrosine have been reported. In this paper, we report for a Gram-positive bacterium that produces hydroxytyrosol via conversion of tyrosol and/or L-tyrosine, identified as a Rhodococcus pyridinivorans based on phenotypic characteristics and 16S rDNA sequence, and designated R. pyridinivorans strain 3HYL DSM109178. Interestingly, strain 3HYL shows an outstanding production of hydroxytyrosol from tyrosol up to 16.4 ± 0.23 mmol/L with high kinetic parameters exceeding the reported values. However, a slight downstream metabolism of the product is assigned to the wild-type strain during the stationary phase of growth. The plasmid-cured strain was obtained using random chemical mutagenesis, designated R. pyridinivorans 3HYL-AO, and was able to produce hydroxytyrosol, with yields up to 21.75 ± 0.34 mmol/L. Moreover, the plasmid-cured strain exhibited a significant reduction in the transformation to its acetic acid forms compared to the wild-type strain as depicted by HPLC analysis. Comparison of kinetic data of the bioconversion/accumulation process between the wild type and mutant strain, in the presence and absence of L-tyrosine, and thus suggesting the occurrence of an upstream pathway for synthesis of tyrosol via (L)-tyrosine.
Olive leaf as an agricultural waste contains valuable bioactive compounds that are mainly used for pharmaceutical and cosmetic industries. Lately the major component, oleuropein, has gained extra attention due to the anti-viral activity against SARS-CoV-2 that causes Coronavirus disease (Covid-19). In this study, extraction of the bioactive compounds from olive leaves was conducted using a non-conventional and green method. New generation green solvents, natural deep eutectic solvents (NADES) were used in combination with ultrasound assisted extraction. Screening of NADES type, temperature, and particle size were investigated using one-pot-at-a-time method while, NADES amount and liquid-to-solid ratio were optimized using experimental design. The results were evaluated in terms of total polyphenol yield (YTP), total flavonoid yield (YTF) and antiradical activity (AAR). At the optimized conditions, the highest total polyphenol yield and the highest total flavonoid yield were achieved with choline chloride–fructose–water (CFW) (5:2:5) as 187.31 ± 10.3 mg gallic acid equivalent g⁻¹ dw and 12.75 ± 0.6 mg apigenin equivalent g⁻¹ dw, respectively. The extracts were also analyzed for oleuropein, caffeic acid and luteolin contents. The highest amount of oleuropein and caffeic acid were extracted by glucose–fructose–water (GFW) (1:1:11) as 1630.80 mg kg⁻¹ dw and 112.77 mg kg⁻¹ dw, respectively.
Graphic Abstract
Dietary components, olive oil and its fractions, are capable to effect on immune network and their mechanisms. Olive oil is a principal source of dietary lipids and polyphenols in the Mediterranean diet, which is especially relevant in the case of extra-virgin olive oil (VOO) and also in VOO. They can effect cytokine production, signaling pathways, and overall health status. This chapter summarizes the key works of olive and olive oil fractions on immune system and several immune-mediated diseases.
Stable oleuropein-coated gold nanoparticles in aqueous media were synthesized for the first time. Oleuropein (OLE) concentration in the reaction medium was found to greatly influence the outcome and stability of the resulting nanocolloid, with a marked decrease in particle size being found for the more concentrated oleuropein solutions. The protection mechanisms involved in the stabilized nanosystems were analyzed. Oleuropein self-assembled structures were found to be formed at a concentration threshold of [OLE] > 5 × 10−5 M, and observed through the use of CryoSEM imaging. Those structures were responsible for both the increased stability and the decrease in size observed at the more concentrated solutions.
According to many reports, phenolic compounds isolated from olive leaves have very good biological activities, especially antimicrobial. Presently, the resistance of microorganisms to antibiotics is greater than ever. Therefore, there are numerous recent papers about alternative solutions for inhibiting their influence on human health. Olive leaf is studied as an important source of antimicrobials with low cost and used in medicine. Numerous publications on involving green technologies for isolation of active compounds from olive leaves have appeared over the past few decades. The present review reports on current knowledge of the most isolated phenolic compounds from olive leaf extract as well as methods for their isolation and characterization. This paper uses recent research findings with a wide range of study models to describe the antimicrobial potential of phenolic compounds. It also describes the vast range of information about methods for determination of antimicrobial potential focusing on effects on different microbes. Additionally, it serves to highlight the role of olive leaf extract as an antioxidants and presents methods for determination of antioxidant potential. Furthermore, it provides an overview of presence of enzymes. The significance of olive leaves as industrial and agricultural waste is emphasized by means of explaining their availability, therapeutic and nutritional effects, and research conducted on this field.
It is known that the Mediterranean diet is effective in reducing the risk of several chronic diseases, including cancer. A critical component of the Mediterranean diet is olive oil, and the relationship between olive oil consumption and the reduced risk of cancer has been established. Oleuropein (OL) is the most prominent polyphenol component of olive fruits and leaves. This compound has been shown to have potent properties in various types of cancers, including breast cancer. In the present study, the molecular mechanism of OL was examined in two racially different triple-negative breast cancer (TNBC) cell lines—African American (AA, MDA-MB-468) and Caucasian American (CA, MDA-MB-231). The data obtained showed that OL effectively inhibits cell growth in both cell lines, concomitant with S-phase cell cycle arrest-mediated apoptosis. The results also showed that OL-treated MDA-MB-468 cells were two-fold more sensitive to OL antiproliferative effect than MDA-MB-231 cells were. At lower concentrations, OL modified the expression of many apoptosis-involved genes. OL was more effective in MDA-MB-468, compared to MDA-MB-231 cells, in terms of the number and the fold-change of the altered genes. In MDA-MB-468 cells, OL induced a noticeable transcription activation in fourteen genes, including two members of the caspase family: caspase 1 (CASP1) and caspase 14 (CASP14); two members of the TNF receptor superfamily: Fas-associated via death domain (FADD) and TNF receptor superfamily 21 (TNFRSF21); six other proapoptotic genes: growth arrest and DNA damage-inducible 45 alpha (GADD45A), cytochrome c somatic (CYCS), BCL-2 interacting protein 2 (BNIP2), BCL-2 interacting protein 3 (BNIP3), BH3 interacting domain death agonist (BID), and B-cell lymphoma/leukemia 10 (BCL10); and the CASP8 and FADD-like apoptosis regulator (CFLAR) gene. Moreover, in MDA-MB-468 cells, OL induced a significant upregulation in two antiapoptotic genes: bifunctional apoptosis regulator (BFAR) and B-Raf proto-oncogene (BRAF) and a baculoviral inhibitor of apoptosis (IAP) repeat-containing 3 (BIRC3). On the contrary, in MDA-MB-231 cells, OL showed mixed impacts on gene expression. OL significantly upregulated the mRNA expression of four genes: BIRC3, receptor-interacting serine/threonine kinase 2 (RIPK2), TNF receptor superfamily 10A (TNFRSF10A), and caspase 4 (CASP4). Additionally, another four genes were repressed, including caspase 6 (CASP6), pyrin domain (PYD), and caspase recruitment domain (CARD)-containing (PAYCARD), baculoviral IAP repeat-containing 5 (BIRC5), and the most downregulated TNF receptor superfamily member 11B (TNFRSF11B, 16.34-fold). In conclusion, the data obtained indicate that the two cell lines were markedly different in the anticancer effect and mechanisms of oleuropein’s ability to alter apoptosis-related gene expressions. The results obtained from this study should also guide the potential utilization of oleuropein as an adjunct therapy for TNBC to increase chemotherapy effectiveness and prevent cancer progression.
The effects of the polyphenolic compounds from virgin olive oil: tyrosol, hydroxytyrosol and oleuropein on the non-enzymatic lipid peroxidation induced by ascorbate-Fe2+ of rat liver microsomes were examined. The inhibition of light emission (maximal induced chemiluminescence) by oleuropein was concentration dependent. Hydroxytyrosol showed a substantial degree of inhibition against ascorbate-Fe2+ induced lipid peroxidation in rat liver microsomes that was at least 6 times higher than that observed in the presence of oleuropein. Inhibition of lipid peroxidation by tyrosol was not observed. In rat liver microsomes incubated alone or in the presence of tyrosol, the fatty acid composition was profoundly modified when subjected to in vitro peroxidation mediated by ascorbate-Fe2+, with a considerable decrease of 18:2n6 and 20:4n6; however, changes in fatty acid composition were not observed when microsomes were incubated with hydroxytyrosol. When oleuropein was used at low concentration (5, 15 μM) a considerable decrease of 20:4n6 was observed, but 18:2n6 was not modified; at higher concentration (30, 60 μM) changes in fatty acid composition were not observed. There was a very good correlation between the presence of oxidized phospholipids and the changes in polyunsaturated fatty acids previously observed. Thus, hydroxytyrosol showed the highest protection again oxidized phospholipid formation. The presence of oleuropein at low concentration (5, 15 μM) does not prevent the formation of oxidized phospholipids (8.02 ± 1.22 and 1.22 ± 1.22) but concentration higher than 30 μM avoids completely the formation of this molecules whereas tyrosol at any concentration assayed was found to be ineffective and allows the formation not only of oxidized phospholipids but also of oxidized cholesterol.
The effects of the polyphenolic compounds from virgin olive oil: tyrosol, hydroxytyrosol and oleuropein on the non-enzymatic lipid peroxidation induced by ascorbate-Fe2+ of rat liver microsomes were examined. The inhibition of light emission (maximal induced chemiluminescence) by oleuropein was concentration dependent. Hydroxytyrosol showed a substantial degree of inhibition against ascorbate-Fe2+ induced lipid peroxidation in rat liver microsomes that was at least 6 times higher than that observed in the presence of oleuropein. Inhibition of lipid peroxidation by tyrosol was not observed. In rat liver microsomes incubated alone or in the presence of tyrosol, the fatty acid composition was profoundly modified when subjected to in vitro peroxidation mediated by ascorbate-Fe2+, with a considerable decrease of 18:2n6 and 20:4n6; however, changes in fatty acid composition were not observed when microsomes were incubated with hydroxytyrosol. When oleuropein was used at low concentration (5, 15 M) a considerable decrease of 20:4n6 was observed, but 18:2n6 was not modified; at higher concentration (30, 60 M) changes in fatty acid composition were not observed. There was a very good correlation between the presence of oxidized phospholipids and the changes in polyunsaturated fatty acids previously observed. Thus, hydroxytyrosol showed the highest protection again oxidized phospholipid formation. The presence of oleuropein at low concentration (5, 15 M) does not prevent the formation of oxidized phospholipids (8.02 1.22 and 1.22 1.22) but concentration higher than 30 M avoids completely the formation of this molecules whereas tyrosol at any concentration assayed was found to be ineffective and allows the formation not only of oxidized phospholipids but also of oxidized cholesterol.
Olive oil is the principal source of fat in the Mediterranean diet, which has been associated with a lower incidence of coronary
heart disease and certain cancers. Olive oil is characterized by a high proportion of monounsaturated oleic acid, but the
main peculiarity of extra-virgin oil is the presence of remarkable quantities of phenolic compounds, notably hydroxytyrosol
and oleuropein, that provide high stability and strong taste. Recently, several studies have demonstrated that olive oil phenolics
are powerful antioxidants, both in vitro and in vivo, and exert additional potent biologic activities that could partially
account for the observed cardioprotective effects of the Mediterranean diet.
Both 2',3'-dideoxyadenosine and 2',3'-dideoxyinosine have been shown (Mitsuya, H., and Broder, S. (1987) Nature 325, 773-778) to have in vitro activity against the human immunodeficiency virus-1 (HIV). However, these dideoxynucleosides may be catabolized by human T cells, even when adenosine deaminase is inhibited by deoxycoformycin. To overcome this problem, we have synthesized the 2-fluoro-, 2-chloro-, and 2-bromo-derivatives of 2',3'-dideoxyadenosine. The metabolism and anti-HIV activity of the 2-halo-2',3'-dideoxyadenosine derivatives and of 2',3'-dideoxyadenosine were compared. The 2-halo-2',3'-dideoxyadenosine derivatives were not deaminated significantly by cultured CEM T lymphoblasts. Experiments with 2-chloro-2',3'-dideoxyadenosine showed that the T cells converted the dideoxynucleoside to the 5'-monophosphate, 5'-diphosphate, and 5'-triphosphate metabolites. At concentrations lower than those producing cytotoxicity in uninfected cells (3-10 microM), the 2-halo-2',3-dideoxyadenosine derivatives inhibited the cytopathic effects of HIV toward MT-2 T lymphoblasts, and retarded viral replication in CEM T lymphoblasts. Experiments with a deoxycytidine kinase-deficient mutant CEM T cell line showed that this enzyme was necessary for the phosphorylation and anti-HIV activity of the 2-chloro-2',3'-dideoxyadenosine. In contrast, 2',3'-dideoxyadenosine was phosphorylated by the deoxycytidine kinase-deficient mutant and retained anti-HIV activity in this cell line. Thus, the 2-halo derivatives of 2',3'-dideoxyadenosine, in contrast to 2',3'-dideoxyadenosine itself, are not catabolized by T cells. Their anti-HIV and anti-proliferative activities are manifest only in cells expressing deoxycytidine kinase. The in vivo implications of these results for anti-HIV chemotherapy are discussed.
Oleuropein, the bitter glucoside in green olives, and products of its hydrolysis were tested for antibacterial action against certain species of lactic acid bacteria involved in the brine fermentation of olives. Oleuropein was not inhibitory, but two of its hydrolysis products, the aglycone and elenolic acid, inhibited growth of the four species of lactic acid bacteria tested. Another hydrolysis product, beta-3,4-dihydroxyphenylethyl alcohol, was not inhibitory. The aglycone of oleuropein and elenolic acid were much more inhibitory when the broth medium contained 5% NaCl; 150 mug of either compound per ml prevented growth of Lactobacillus plantarum. A crude extract of oleuropein, tested by paper disk bioassay, was inhibitory to 3 of 17 species of bacteria screened, none of which were lactic acid bacteria. The acid hydrolysate of the extract was inhibitory to 11 of the bacteria, which included four species of lactic acid bacteria and other gram-positive and gram-negative species. Neither crude preparation was inhibitory to growth of the seven species of yeasts tested. A possible explanation is given for the previously reported observation that heating (3 min, 74 C) olives prior to brining renders them more fermentable by lactic acid bacteria. Results of a brining experiment indicated that oleuropein is degraded to antibacterial compounds when unheated olives are brined.
GAP31 (gelonium anti-HIV protein of 31 kDa) is an anti-HIV protein which we have identified and purified from a medicinal plant, Gelonium multiflorum. It is capable of inhibiting HIV-1 infection and replication. GAP31 also exhibits DNA topoisomerase inhibitor activity and RNA N-glycosidase activity. The ability of GAP31 to interrupt both DNA and RNA functions may be related to its multiple antiviral actions. To define the roles of these activities in the anti-HIV action of GAP31, a series of peptides corresponding to the N-terminal segment of GAP31 were synthesized and assayed for the aforementioned activities of the parent molecule. A 33-aa segment (KGATYITYVNFLNELRVKTKPEGNSHGIPSLRK) designated as K10-K42 is the shortest peptide necessary and sufficient for HIV-1 inhibition, DNA and RNA binding, and ribosome inactivation. The peptides were 2-5 orders of magnitude less active than GAP31. Truncation of 19 aa from the C terminus of K10-K42 resulted in the loss of all of these activities. On the other hand, deletion of N-terminal residues to give E23-K42 did not alter ribosome-inactivation activity but eliminated the other activities. These findings permit identification of a 7-aa sequence, KGATYIT, at the N terminus of K10-K42 that is critical for DNA binding and RNA binding, whereas a 9-aa sequence, SHGIPSLRK, at the C terminus is important to ribosome inactivation. Both regions contribute to anti-HIV activity. Histidine at position 35 is critical for all of these activities. The disparity of sequence requirements for inhibition of HIV infection and replication and for ribosome-inactivation activity suggests that the anti-HIV activity of most ribosome-inactivating proteins may not be the result of N-glycosidase activity alone. Mapping the minimal domain of GAP31 offers insights into the rational design of molecular mimetics of anti-HIV drugs.
The hedgehog (Hh) signaling pathway is involved in the development of many tissues. Here we show that sonic hedgehog (Shh) is involved in thymocyte development. Our data suggest that termination of Hh signaling is necessary for differentiation from CD4-CD8-double-negative (DN) to CD4+CD8+ double-positive (DP) thymocyte. Shh is produced by the thymic stroma, and Patched and Smoothened (Smo), the transmembrane receptors for Shh, are expressed in DN thymocytes. A neutralizing monoclonal antibody against Shh increases differentiation of DN to DP thymocytes, and Shh protein arrests thymocyte differentiation at the CD25+ DN stage, after T cell receptor beta (TCRbeta) gene rearrangement. We show that one consequence of pre-TCR signaling is downregulation of Smo, allowing DN thymocytes to proliferate and differentiate.
Interest in the health-promoting effects of virgin olive oil, an important part of the "Mediterranean diet", prompted us to determine the antiinflammatory effects of erythrodiol, beta-sitosterol and squalene, identified as major components of the so-called "unsaponifiable fraction" of virgin olive oil, as well as of the phenolic compounds from the "polar fraction": oleuropein, tyrosol, hydroxytyrosol and caffeic acid. Their activities were compared to those of both, total unsaponifiable and polar fractions. This study was designed to analyse the antiinflammatory effect of these specific compounds from virgin olive oil on edema in mice induced by either arachidonic acid (AA) or 12-O-tetradecanoylphorbol acetate (TPA). The inhibition of the myeloperoxidase (MPO), marker enzyme of the accumulation of neutrophils in the inflamed tissue, was also investigated by the TPA model. The topical application of the olive oil compounds (0.5 mg/ear) produced a variable degree of antiinflammatory effect with both assays. In the auricular edema induced by TPA, beta-sitosterol and erythrodiol from the unsaponifiable fraction of the oil showed a potent antiedematous effect with a 61.4% and 82.1% of inhibition respectively, values not very different to that of the reference indomethacin (85.6%) at 0.5 mg/ear. The four phenolics exerted a similar range of inhibition (33-45%). All compounds strongly inhibited the enzyme myeloperoxidase, indicating a reduction of the neutrophil influx in the inflamed tissues. The strongest inhibitor of AA edema was the total unsaponifiable fraction which inhibition was 34%, similar to that obtained by the reference drug dexamethasone at 0.05 mg/ear. Among the phenolics, oleuropein also produced an inhibition of about 30% with the same dose, but all the other components were found less active in this assay. The anti-inflammatory effects exerted by both unsaponifiable and polar compounds might contribute to the potential biological properties reported for virgin olive oil against different pathological processes.
In the present work, virgin olive oil, sunflower oil and a vegetable shortening were used as cooking oils for the deep-frying and pan-frying of potatoes, for eight successive sessions, under the usual domestic practice. Several chemical and physicochemical parameters (acidic value, peroxide value, total polar artefacts, total phenol content and triglyceride fatty acyl moiety composition) were assayed during frying operations in order to evaluate the status of the frying oils, which were found within expected ranges similar to those previously reported. The oil fatty acids were effectively protected from oxidation by the natural antioxidants. The frying oil absorption by the potatoes was quantitated within 6.1-12.8%, depending on the oil type and the frying process. The retention of α- and (β + γ)-tocopherols during the eight fryings ranged from 85-90% (first frying) to 15-40% (eighth frying), except for the (β + γ)-tocopherols of sunflower oil, which almost disappeared after the sixth frying. The deterioration during the successive frying of several phenolic species present in virgin olive oil is reported for the first time. The retention of total phenolics ranged from 70-80% (first frying) to 20-30% (eighth frying). Tannic acid, oleuropein and hydroxytyrosol-elenolic acid dialdeydic form showed remarkable resistance in all frying sessions in both frying methods, while hydroxytyrosol and hydroxytyrosol-elenolic acid were the faster eliminated. The deterioration of the other phenolic species account for 40-50% and 20-30% for deep-frying and pan-frying, respectively, after three to four frying sessions, which are the most usual in the household kitchen. Deep-frying resulted in better recoveries of all the parameters examined. The correlation of the deterioration rate of the phenolic compounds and tocopherols during frying is discussed and the nutritional aspects of the natural antioxidant intake, through the oil absorbed by the potatoes, are evaluated.
Sonic hedgehog (Shh) is important in the growth and differentiation of a variety of cell types, including the development of T cells in the thymus. This prompted us to investigate whether Shh signaling is a functional component of the physiological response of human mature CD4(+) T cells following Ag recognition. In this study, we demonstrate that Shh and its receptor Patched (Ptc) are expressed on resting and activated human peripheral CD4(+) T cells. In approximately one-half of the randomly selected, anonymous blood donors tested, exposure of anti-CD3/28 Ab-activated CD4(+) T cells to the biologically active N-terminal Shh peptide increased the transcription of ptc, thereby demonstrating that Shh signaling had occurred. Furthermore, the addition of exogenous Shh amplified the production of IL-2, IFN-gamma, and IL-10 by activated CD4(+) T cells. The synthesis of IL-2 and IFN-gamma, but not IL-10, by CD4(+) T cells was down-regulated by the addition of neutralizing anti-Shh Ab. Cell surface expression of CD25 and CD69 on activated T cells was up-regulated by exogenous Shh, whereas in the presence of the neutralizing anti-Shh Ab expression it was reduced. Collectively, our findings demonstrate that Shh-mediated signaling is a physiological component of T cell responses, which acts to modulate CD4(+) T cell effector function.
Epidemiology suggests that Mediterranean diets are associated with reduced risk of cardiovascular disease. Because monocyte adhesion to the endothelium is crucial in early atherogenesis, we evaluated whether typical olive oil and red wine polyphenols affect endothelial-leukocyte adhesion molecule expression and monocyte adhesion.
Phytochemicals in olive oil and red wine, including oleuropein, hydroxytyrosol, tyrosol, elenolic acid, and resveratrol, with or without antioxidant activity, were incubated with human umbilical vein endothelial cells for 30 minutes, followed by co-incubation with bacterial lipopolysaccharide or cytokines to trigger adhesion molecule expression. At nutritionally relevant concentrations, only oleuropein, hydroxytyrosol, and resveratrol, possessing a marked antioxidant activity, reduced monocytoid cell adhesion to stimulated endothelium, as well as vascular cell adhesion molecule-1 (VCAM-1) mRNA and protein by Northern analysis and cell surface enzyme immunoassay. Reporter gene assays with deletional VCAM-1 promoter constructs indicated the relevance of nuclear factor-kappaB, activator protein-1, and possibly GATA binding sites in mediating VCAM-1 transcriptional inhibition. The involvement of nuclear factor-kappaB and activator protein-1 was finally demonstrated at electrophoretic mobility shift assays.
Olive oil and red wine antioxidant polyphenols at nutritionally relevant concentrations transcriptionally inhibit endothelial adhesion molecule expression, thus partially explaining atheroprotection from Mediterranean diets.
The Mediterranean diet, rich in fresh fruits and vegetables, has been associated with a lower incidence of cardiovascular disease and cancer, partly because of its high proportion of bioactive compounds such as vitamins, flavonoids and polyphenols. The major lipid component of such diet is the drupe-derived olive oil, that can be distinguished from other seed oils for the peculiar composition of its non-triglyceride fraction. In fact, several minor components, including polyphenols, grant the oil its particular taste and aroma. Oleuropein, the most abundant among these components, has been shown to be a potent antioxidant endowed with antiinflammatory properties. We investigated the effects of oleuropein on NO release in cell culture and its activity toward nitric oxide synthase (iNOS) expression. The results show that oleuropein dose-dependently enhance nitrite production in LPS-challenged mouse macrophages. This effect was blocked by the iNOS inhibitor L-NAME, indicating increased iNOS activity. Also, Western blot analysis of cell homogenates show that oleuropein increases iNOS expression in such cells. Taken together, our data suggest that, during endotoxin challenge, oleuropein potentiates the macrophage-mediated response, resulting in higher NO production, currently believed to be beneficial for cellular and organismal protection.
A new inhibitor of human immunodeficiency virus (HIV) has been isolated and purified to homogeneity from the seeds and fruits of the Momordica charantia. This compound, MAP 30 (Momordica Anti-HIV Protein), is a basic protein of about 30 kDa. It exhibits dose-dependent inhibition of cell-free HIV-1 infection and replication as measured by: (i) quantitative focal syncytium formation on CEM-ss monolayers; (II) viral core protein p24 expression; and (iii) viral-associated reverse transcriptase (RT) activity in HIV-1 infected H9 cells. The doses required for 50% inhibition (ID50) in these assays were 0.83, 0.22 and 0.33 nM, respectively. No cytotoxic or cytostatic effects were found under the assay conditions. These data suggest that MAP 30 may be a useful therapeutic agent in the treatment of HIV-1 infections. The sequence of the N-terminal 44 amino acids of MAP 30 has been determined.
The anti-HIV agent MAP30 (Momordica anti-HIV protein, 30 kDa) inhibits the proliferation of BC-2, an AIDS-related primary effusion lymphoma (PEL) cell line derived from an AIDS patient. BC-2 cells are latently infected with Kaposi's sarcoma-associated herpes virus (KSHV), also known as human herpes virus 8 (HHV8). We examined the effect of MAP30 on the expression of viral and cellular genes in BC-2 during latent and lytic states of the viral life cycle. By Northern analysis and RT-PCR, we found that MAP30 downregulates the expression of viral cyclin D (vCD), viral interleukin-6 (vIL-6), and viral FLIP (vFLIP), genes involved in cell cycle regulation, viral pathogenesis, and apoptosis. By pathway-specific cDNA microarray analysis, we found that BC-2 cells express high levels of egr-1, ATF-2, hsp27, hsp90, IκB, mdm2, skp1, and IL-2, cellular genes involved in mitogenesis, tumorigenesis, and inhibition of apoptosis in NFκB and p53 signaling pathways. These results define for the first time the specific cellular pathways involved in AIDS-related tumorigenesis and suggest specific novel targets for the treatment. Furthermore, we found that MAP30 downregulates the expression of egr-1, ATF-2, hsp27, hsp90, IκB, mdm2, and Skp1, while it upregulates the pro-apoptotic-related genes Bax, CRADD, and caspase-3. Thus, MAP30 modulates the expression of both viral and cellular genes involved in KS pathogenesis. These results provide valuable insight into the molecular mechanisms of MAP30 anti-KS action and suggest its utility as a therapeutic agent against AIDS-related tumors.
The Mediterranean diet, rich in fruit, vegetables, grain, and vegetable oil (mainly olive oil) is correlated with a lower incidence of coronary heart disease (CHD). Natural antioxidants contained in the Mediterranean diet might also play a role in the prevention of cardiovascular diseases, through inhibition of LDL oxidation. We tested this hypothesis “in vitro” by inducing LDL oxidation with copper sulphate and preincubating the samples with oleuropein, the bitter principle of olive, that is one of the major components of the polyphenolic fraction of olive oil. Oleuropein 10−5 M effectively inhibited CuSO4-induced LDL oxidation, as assessed by various parameters. We demonstrate in this investigation that polyphenolic components of the Mediterranean diet interfere with biochemical events that are implicated in atherogenetic disease, thus proposing a new link between the Mediterranean diet and prevention of CHD.
This study was designed to investigate the in vitro effects of phenolic compounds extracted from olive oil and from olive derived fractions. More specifically, we investigated the effects on platelets of 2-(3,4-di-hydroxyphenyl)-ethanol (DHPE), a phenol component of extra-virgin olive oil with potent antioxidant properties. The following variables were studied: aggregation of platelet rich plasma (PRP) induced by ADP or collagen, and thromboxane B2 production by collagen or thrombin-stimulated PRP. In addition, thromboxane B2 and 12-hydroxyeicosatetraenoic acid (12-HETE) produced during blood clotting were measured in serum. Preincubation of PRP with DHPE for at least 10 min resulted in maximal inhibition of the various measured variables. The IC50s (concentration resulting in 50% inhibition) of DHPE for ADP- or collagen-induced PRP aggregations were 23 and 67 μM, respectively. At 400 μM DHPE, a concentration which completely inhibited collagen-induced PRP aggregation, TxB2 production by collagen- or thrombin-stimulated PRP was inhibited by over 80 percent. At the same DHPE concentration, the accumulation of TxB2 and 12-HETE in serum was reduced by over 90 and 50 percent, respectively. We also tested the effects on PRP aggregation of oleuropein, another typical olive oil phenol, and of selected flavonoids (luteolin, apigenin, quercetin) and found them to be much less active. On the other hand a partially characterized phenol-enriched extract obtained from aqueous waste from olive oil showed rather potent activities. Our results are the first evidence that components of the phenolic fraction of olive oil can inhibit platelet function and eicosanoid formation in vitro, and that other, partially characterized, olive derivatives share these biological activities.
Oleuropein, the bitter glucoside of olives, and its hydrolysis products can possess antibacterial action. However, there is no information on the possible utilization of this polyphenolic compound; therefore studies have been made to assess its utilization as a major source of carbon. Various microorganisms associated with fermentation of olives (both desirable lactic acid bacteria and spoilage organisms) did use oleuropein, many without a significant delay in growth resulting in the appearance of a strong visible turbidity. Although the increase in oleuropein from 0.2 to 0.4% (w/v) had little or no effect on the spoilage organisms, the additional glucoside caused a delay in development of growth with some of the lactic acid bacteria. However, all of the latter cultures tested eventually grew and developed strong visible turbidity.
The human T-cell lines MT-2 and MT-4 carry the human T-cell leukemia virus type I (HTLV-I). When MT-2 and MT-4 were infected with HTLV-III, the probable etiologic agent of the acquired immune deficiency syndrome (AIDS), rapid cytopathogenic effects and cytotoxicity were observed that made it possible to titrate the biologically active virus in a plaque-forming assay. The cytopathogenic effects were preceded by the rapid induction and increase of HTLV-III antigens as revealed by immunofluorescence and immunoprecipitation. Activities of HTLV-III were neutralized by the human antibodies against the virus when immunofluorescence and plaque assays were used. Essentially the same results were obtained with the lymphadenopathy-associated virus (LAV1).
The development of a cytomorphologic infectivity microbioassay for human immunodeficiency virus (HIV) allows rapid, sensitive, and specific characterization of neutralizing antibodies or antiviral agents.
. Treatment of green olives for 2 min with dilute hot alkali before brining increased the release of sugars, B complex vitamins, amino acids and phenolic compounds, and enhanced the establishment of lactic acid bacteria in the brine. Two components of the ethyl acetate extract of green olives, which showed an antibacterial activity, were isolated and identified as the glycoside oleuropein and its phenolic aglycone. The inhibition of Lactobacillus plantarum by the ethyl acetate extract or by oleuropein was augmented by reducing the concentration of organic nitrogenous compounds, increasing the NaCl concentration in the assay medium and decreasing the inoculum size. Besides its activity towards various bacteria, oleuropein inhibited the growth of Geotrichum candidum Link, Rhizopus sp. and Rhizoctonia solani Kühn. On the basis of these findings, an explanation for some problems in the lactic fermentation of green olives is suggested.
A cell system was developed for the reproducible detection of human T-lymphotropic retroviruses (HTLV family) from patients with the acquired immunodeficiency syndrome (AIDS) or with signs or symptoms that frequently precede AIDS (pre-AIDS). The cells are specific clones from a permissive human neoplastic T-cell line. Some of the clones permanently grow and continuously produce large amounts of virus after infection with cytopathic (HTLV-III) variants of these viruses. One cytopathic effect of HTLV-III in this system is the arrangement of multiple nuclei in a characteristic ring formation in giant cells of the infected T-cell population. These structures can be used as an indicator to detect HTLV-III in clinical specimens. This system opens the way to the routine detection of HTLV-III and related cytopathic variants of HTLV in patients with AIDS or pre-AIDS and in healthy carriers, and it provides large amounts of virus for detailed molecular and immunological analyses.
The importance of ornithine decarboxylase (ODC) to cell proliferation is underscored by the complex array of cell-specific
mechanisms invoked to regulate its synthesis and activity. Misregulation of ODC has severe negative consequences on normal
cell function, including the acquisition of tumorigenic growth properties by cells overexpressing ODC. We hypothesize that
ODC gene expression is a candidate target for the anti-proliferative function of certain tumor suppressors. Here we show that
the Wilms' tumor suppressor WT1 binds to multiple sites within the human ODC promoter, as determined by DNase I protection
and methylation interference assays. The expression of WT1 in transfected HCT 116, NIH/3T3 and HepG2 cells represses activity
of the ODC promoter controlling expression of a luciferase reporter gene. In contrast, WT1 expression enhances ODC promoter
activity in SV40-transfected HepG2 cells. Both the extent of modulation of ODC gene expression and the mediating WT1 binding
elements are cell specific. Constructs expressing WT1 deletion mutants implicate two regions required for repressor function,
as well as an intrinsic activation domain. Understanding the regulation of ODC gene expression by WT1 may provide valuable
insights into the roles of both WT1 and ODC in development and tumorigenesis.
This study sought to update national estimates of the use of alternative therapies, to improve the quality of those estimates, and to examine differences between users and nonusers of alternative medicine. Data were analyzed from the general probability sample (N = 3450) of the 1994 Robert Wood Johnson Foundation National Access to Care Survey. The results indicate that nearly 10% of the U.S. population, almost 25 million persons, saw a professional in 1994 for at least one of the following four therapies: chiropractic, relaxation techniques, therapeutic massage, or acupuncture. Even though users of alternative therapies made almost twice as many visits to conventional (or orthodox) medical providers as nonusers made, the former still reported much higher levels of unmet need for medical care. The growing emphasis on market-driven health care and consumer choice suggests that alternative therapies could have a larger role in the health-care system of the future.
The antimicrobial potential of eight phenolic compounds isolated from olive cake was tested against the growth of Escherichia coli, Klebsiella pneumoniae, Bacillus cereus, Aspergillus flavus and Aspergillus parasiticus. The phenolic compounds included p-hydroxy benzoic, vanillic, caffeic, protocatechuic, syringic, and p-coumaric acids, oleuropein and quercetin. Caffeic and protocatechuic acids (0.3 mg/ml) inhibited the growth of E. coli and K. pneumoniae. The same compounds apart from syringic acid (0.5 mg/ml) completely inhibited the growth of B. cereus. Oleuropein, and p-hydroxy benzoic, vanillic and p-coumaric acids (0.4 mg/ml) completely inhibited the growth of E. coli, K. pneumoniae and B. cereus. Vanillic and caffeic acids (0.2 mg/ml) completely inhibited the growth and aflatoxin production by both A. flavus and A. parasiticus, whereas the complete inhibition of the moulds was attained with 0.3 mg/ml p-hydroxy benzoic, protocatechuic, syringic, and p-coumaric acids and quercetin.
The Hedgehog (Hh) family of secreted proteins is involved in a number of developmental processes as well as in cancer. Genetic and biochemical data suggest that the Sonic hedgehog (Shh) receptor is composed of at least two proteins: the tumor suppressor protein Patched (Ptc) and the seven-transmembrane protein Smoothened (Smo).
Using a biochemical assay for activation of the transcription factor Gli, a downstream component of the Hh pathway, we show here that Smo functions as the signaling component of the Shh receptor, and that this activity can be blocked by Ptc. The inhibition of Smo by Ptc can be relieved by the addition of Shh. Furthermore, oncogenic forms of Smo are insensitive to Ptc repression in this assay. Mapping of the Smo domains required for binding to Ptc and for signaling revealed that the Smo-Ptc interaction involves mainly the amino terminus of Smo, and that the third intracellular loop and the seventh transmembrane domain are required for signaling.
These data demonstrate that Smo is the signaling component of a multicomponent Hh receptor complex and that Ptc is a ligand-regulated inhibitor of Smo. Different domains of Smo are involved in Ptc binding and activation of a Gli reporter construct. The latter requires the third intracellular loop and the seventh transmembrane domain of Smo, regions often involved in coupling to G proteins. No changes in the levels of cyclic AMP or calcium associated with such pathways could be detected following receptor activation, however.
Substantial evidence suggests that oxidative modifications of low density lipoproteins (LDL) critically contribute to the pathogenesis and progression of human atherosclerosis. Oxidized LDL (oxLDL) are present in atherosclerotic plaques and contain oxysterols that exhibit a variety of adverse biological activities. Antioxidants have also been shown to prevent LDL modification. We have therefore assessed the efficacy of virgin olive oil phenolic compounds in preventing oxidative modifications of human LDL oxidized by UV light.
Cholesterol oxides formed during LDL photo-oxidation were determined by UV-HPLC in the presence of different concentrations of phenolic compounds and their pure components (tyrosol and oleuropein), and probucol, a widely used synthetic antioxidant. Electrophoretic mobility was also assayed. The results demonstrate that phenolic compounds are much more potent in preventing cholesterol oxide formation and apoproteic moiety modification than their pure components and probucol.
The beneficial effects of a Mediterranean diet may be ascribable not only to the high unsaturated/saturated fatty acid ratio characteristic of olive oil, but also to the unique antioxidant properties of its phenolic compounds.
Olive oil contains several phenolic compounds with antioxidant activity, whose levels depend strongly on the kind of cultivar grown, fruit ripening effects and the oil extraction process. Therefore, the beneficial effects exerted by olive oil consumption on the resistance of low density lipoproteins (LDLs) to oxidation depend not only on an increased intake of mono-unsaturated fatty acids (e.g. oleate) which are less prone to oxidation, but also phenolic antioxidants. The aim of this study was to analyze in vitro effects exerted on the oxidative modification of Cu-stimulated human LDL by two olive oil biophenols, i.e. 3,4-dihydroxyphenylethanol-elenolic acid (3,4-DHPEA-EA) and protocatecuic acid. These compounds have not been investigated in as much detail as the better-known olive oil biophenols - such as tyrosol (p-HPEA), o-coumaric acid, vanillic acid, caffeic acid, oleuropein and 3,4-dihydroxyphenylethanol (3,4-DHPEA). Modification of LDL was tested by measuring the formation of intermediate and end products of lipid peroxidation such as conjugated dienes, lipid hydroperoxides, cholesterol and cholesteryl ester oxides, as well as studying the decrease in oxidizable substrates like polyunsaturated fatty acids. In addition, the increase in LDL negative charges was evaluated. The results demonstrate the two-tested olive oil biophenols show high antioxidant activities. In particular, protocatecuic acid and 3,4-DHPEA-EA show an antioxidant activity comparable with that of caffeic acid, oleuropein and 3,4-DHPEA. They are not only able to retard lipid peroxidation, but also to reduce the extent of its activity.
Secoiridoides (oleuropein and derivatives), one of the major classes of polyphenol contained in olives and olive oil, have recently been shown to inhibit or delay the rate of growth of a range of bacteria and microfungi but there are no data in the literature concerning the possible employment of these secoiridoides as antimicrobial agents against pathogenic bacteria in man.
In this study five ATCC standard bacterial strains (Haemophilus influenzae ATCC 9006, Moraxella catarrhalis ATCC 8176, Salmonella typhi ATCC 6539, Vibrio parahaemolyticus ATCC 17802 and Staphylococcus aureus ATCC 25923) and 44 fresh clinical isolates (Haemophilus influenzae, eight strains, Moraxella catarrhalis, six strains, Salmonella species, 15 strains, Vibrio cholerae, one strain, Vibrio alginolyticus, two strains, Vibrio parahaemolyticus, one strain, Staphylococcus aureus, five penicillin-susceptible strains and six penicillin-resistant strains), causal agents of intestinal or respiratory tract infections in man, were tested for in-vitro susceptibility to two olive (Olea europaea) secoiridoides, oleuropein (the bitter principle of olives) and hydroxytyrosol (derived from oleuropein by enzymatic hydrolysis and responsible for the high stability of olive oil). The minimum inhibitory concentrations (MICs) calculated in our study are evidence of the broad antimicrobial activity of hydroxytyrosol against these bacterial strains (MIC values between 0.24 and 7.85 μg mL−1 for ATCC strains and between 0.97 and 31.25 μg mL−1 for clinically isolated strains). Furthermore oleuropein also inhibited (although to a much lesser extent) the growth of several bacterial strains (MIC values between 62.5 and 500 μg mL−1 for ATCC strains and between 31.25 and 250 μg mL−1 for clinical isolates); oleuropein was ineffective against Haemophilus influenzae and Moraxella catarrhalis.
These data indicate that in addition to the potential employment of its active principles as food additives or in integrated pest-management programs, Olea europaea can be considered a potential source of promising antimicrobial agents for treatment of intestinal or respiratory tract infections in man.
On the basis of the results obtained with pilot studies conducted in vitro on human low density lipoprotein (LDL) and on cell cultures (Caco-2), which had indicated the ability of certain molecules present in olive oil to inhibit prooxidative processes, an in vivo study was made of laboratory rabbits fed special diets. Three different diets were prepared: a standard diet for rabbits (diet A), a standard diet for rabbits modified by the addition of 10% (w/w) extra virgin olive oil (diet B), a modified standard diet for rabbits (diet C) differing from diet B only in the addition of 7 mg kg(-1) of oleuropein. A series of biochemical parameters was therefore identified, both in the rabbit plasma and the related isolated LDL, before and after Cu-induced oxidation. The following, in particular, were selected: (i) biophenols, vitamins E and C, uric acid, and total, free, and ester cholesterol in the plasma; (ii) proteins, triglycerides, phospholipids, and total, free, and ester cholesterol in the native LDL (for the latter, the dimensions were also measured); (iii) lipid hydroperoxides, aldehydes, conjugated dienes, and relative electrophoretic mobility (REM) in the oxidized LDL (ox-LDL). In an attempt to summarize the results obtained, it can be said that this investigation has not only verified the antioxidant efficacy of extra virgin olive oil biophenols and, in particular, of oleuropein, but has also revealed a series of thus far unknown effects of the latter on the plasmatic lipid situation. In fact, the addition of oleuropein in diet C increased the ability of LDL to resist oxidation (less conjugated diene formation) and, at the same time, reduced the plasmatic levels of total, free, and ester cholesterol (-15, -12, and -17%, respectively), giving rise to a redistribution of the lipidic components of LDL (greater phospholipid and cholesterol amounts) with an indirect effect on their dimensions (bigger by about 12%).
Olive oil is the principal source of fats in the Mediterranean diet, which has been associated with a lower incidence of coronary heart disease and certain cancers. Phenolic compounds, e.g., hydroxytyrosol and oleuropein, in extra-virgin olive oil are responsible for its peculiar pungent taste and for its high stability. Recent findings demonstrate that olive oil phenolics are powerful antioxidants, both in vitro and in vivo, and possess other potent biological activities that could partially account for the observed healthful effects of the Mediterranean diet.
Animal and in vitro studies suggest that olive oil phenols are effective antioxidants. The most abundant phenols in olive oil are the nonpolar oleuropein- and ligstroside-aglycones and the polar hydroxytyrosol and tyrosol. The aim of this study was to gain more insight into the metabolism of those phenols in humans. We measured their absorption in eight healthy ileostomy subjects. We also measured urinary excretion in the ileostomy subjects and in 12 volunteers with a colon. Subjects consumed three different supplements containing 100 mg of olive oil phenols on separate days in random order. Ileostomy subjects consumed a supplement with mainly nonpolar phenols, one with mainly polar phenols and one with the parent compound oleuropein-glycoside. Subjects with a colon consumed a supplement without phenols (placebo) instead of the supplement with oleuropein-glycoside. Ileostomy effluent and urine were collected for 24 h after supplement intake. Tyrosol and hydroxytyrosol concentrations were low (< 4 mol/100 mol of intake) in the ileostomy effluent, and no aglycones were detected. We estimated that the apparent absorption of phenols was at least 55-66% of the ingested dose. Absorption was confirmed by the excretion of tyrosol and hydroxytyrosol in urine. In ileostomy subjects, 12 mol/100 mol and in subjects with a colon, 6 mol/100 mol of the phenols from the nonpolar supplement were recovered in urine as tyrosol or hydroxytyrosol. In both subject groups, 5--6 mol/100 mol of the phenols was recovered from the polar supplement. When ileostomy subjects were given oleuropein-glycoside, 16 mol/100 mol was recovered in 24-h urine, mainly in the form of hydroxytyrosol. Thus, humans absorb a large part of ingested olive oil phenols and absorbed olive oil phenols are extensively modified in the body.
In the Mediterranean basin, olive oil, along with fruits, vegetables, and fish, is an important constituent of the diet, and is considered a major factor in preserving a healthy and relatively disease-free population. Epidemiological data show that the Mediterranean diet has significant protective effects against cancer and coronary heart disease. We present evidence that it is the unique profile of the phenolic fraction, along with high intakes of squalene and the monounsaturated fatty acid, oleic acid, which confer its health-promoting properties. The major phenolic compounds identified and quantified in olive oil belong to three different classes: simple phenols (hydroxytyrosol, tyrosol); secoiridoids (oleuropein, the aglycone of ligstroside, and their respective decarboxylated dialdehyde derivatives); and the lignans [(+)-1-acetoxypinoresinol and pinoresinol]. All three classes have potent antioxidant properties. High consumption of extra-virgin olive oils, which are particularly rich in these phenolic antioxidants (as well as squalene and oleic acid), should afford considerable protection against cancer (colon, breast, skin), coronary heart disease, and ageing by inhibiting oxidative stress.
Typical components of the Mediterranean diet, such as olive oil and red wine, contain high concentrations of complex phenols, which have been suggested to have an important antioxidant role. The aim of the present work was to determine the inhibitory potency of compounds such as oleuropein, hydroxytyrosol, and other structurally related compounds, such as gallic acid, toward reactive oxygen species generation and free radical scavenging ability. The potency of these compounds was also examined with respect to protecting in vitro low-density lipoprotein oxidation. These studies indicate that complex phenols, such as hydroxytyrosol, and gallic acid both inhibit free radical generation and act as free radical scavengers. The use of three different approaches to determine antioxidant potency demonstrates that activity in one test does not necessarily correlate with activity in another. It was also demonstrated that the presence of two phenolic groups is not always associated with antioxidant activity.
Olive oil is the principal source of fat in the Mediterranean diet, which has been associated with a lower incidence of coronary heart disease and certain cancers. Extra-virgin olive oil contains a considerable amount of phenolic compounds, for example, hydroxytyrosol and oleuropein, that are responsible for its peculiar taste and for its high stability. Evidence is accumulating to demonstrate that olive oil phenolics are powerful antioxidants, both in vitro and in vivo; also, they exert other potent biological activities that could partially account for the observed healthful effects of the Mediterranean diet.
The activity of oleuropein, a phenolic glycoside contained in olive oil, was investigated in vitro against Mycoplasma hominis, Mycoplasma fermentans, Mycoplasma pneumoniae and Mycoplasma pirum. Oleuropein inhibited mycoplasmas at concentrations from 20 to 320 mg/l. The MICs of oleuropein to M. pneumoniae, M. pirum, M. hominis and M. fermentans were 160, 320, 20 and 20 mg/l, respectively.
It has been postulated that the components in olive oil in the Mediterranean diet, a diet which is largely vegetarian in nature, can contribute to the lower incidence of coronary heart disease and prostate and colon cancers. The Mediterranean diet includes the consumption of large amounts of olive oil. Olive oil is a source of at least 30 phenolic compounds. The major phenolic compounds in olive oil are oleuropein, hydroxytyrosol and tyrosol. Recently there has been a surge in the number of publications that has investigated their biological properties. The phenolic compounds present in olive oil are strong antioxidants and radical scavengers. Olive "waste water" also possesses compounds which are strong antioxidant and radical scavengers. Typically, hydroxytyrosol is a superior antioxidant and radical scavenger to oleuropein and tyrosol. Hydroxytyrosol and oleuropein have antimicrobial activity against ATTC bacterial strains and clinical bacterial strains. Recent syntheses of labeled and unlabelled hydroxytyrosol coupled with superior analytical techniques have enabled its absorption and metabolism to be studied. It has recently been found that hydroxytyosol is renally excreted unchanged and as the following metabolites as its glucuronide conjugate, sulfate conjugate, homovanillic acid, homovanillic alcohol, 3,4-dihydroxyphenylacetic acid and 3,4-dihydroxyphenylacetaldehyde. Studies with tyrosol have shown that it is excreted unchanged and as its conjugates. This review summarizes the antioxidant abilities; the scavenging abilities and the biological fates of hydroxytyrosol, oleuropein and tyrosol which have been published in recent years.
The Hedgehog (Hh) and Wnt family proteins, and the bone morphogenetic proteins (BMPs) 2 and 4, act as morphogens during vertebrate embryogenesis and organogenesis by regulating patterning and cell fate. They have recently been found to have a role in regulating cell fate and determination in self-renewing tissues in adults, such as the immune system and haematopoietic system. This Review presents studies on the role of Sonic Hh (Shh), Wnts and BMP2/4 in the regulation of thymocyte development. Shh and BMP2/4 act as negative regulators of thymocyte development. By contrast, Wnt signalling, through beta-catenin, has a positive role in the control of T-cell development, such that an absence or reduction in the Wnt signal leads to a reduction in cell number and cell proliferation rate and differentiation to the CD4+CD8+ double-positive stage.
Antimicrobial properties of oleuropein and products of its hydrolysis from green olives Comparative antibacterial and antifungal effects of some phenolic compounds
- H P Fleming
- W M Walter
- J L Jr
- Etchells
H.P. Fleming, W.M. Walter Jr., J.L. Etchells, Antimicrobial properties of oleuropein and products of its hydrolysis from green olives, Appl. Microbiol. 26 (1973) 777 782. [5] N.H. Aziz, S.E. Farag, L.A. Mousa, M.A. Abo-Zaid, Comparative antibacterial and antifungal effects of some phenolic compounds, Microbios 93 (1998) 43–54.
Olive leaf extract. The new oral treatment to counteract most types of pathological organisms
- Walker
M. Walker, Olive leaf extract. The new oral treatment to counteract
most types of pathological organisms, Explore 7 (1996).
- P M Furneri
- A Marino
- A Saija
- N Uccella
- G Bisignano
P.M. Furneri, A. Marino, A. Saija, N. Uccella, G. Bisignano, In
vitro antimycoplasmal activity of oleuropein, Int. J. Antimicrob.
Agents 20 (2002) 293–296.
Inhibition of platelet aggregation and eicosanoid production by phenolic components of olive oil
- A Petroni
- M Blasevich
- M Salami
- N Papini
- G F Montedoro
- C Galli
A. Petroni, M. Blasevich, M. Salami, N. Papini, G.F. Montedoro,
C. Galli, Inhibition of platelet aggregation and eicosanoid
production by phenolic components of olive oil, Thromb. Res.
78 (1995) 151–160.
- S Lee-Huang
- P L Huang
- P L Nara
- H C Chen
- H F Kung
- P Huang
- H I Huang
S. Lee-Huang, P.L. Huang, P.L. Nara, H.C. Chen, H.F. Kung, P.
Huang, H.I. Huang, MAP 30: a new inhibitor of HIV-1 infection
and replication, FEBS Lett. 272 (1990) 12-18.
Inhibition of platelet aggregation and eicosanoid production by phenolic components of olive oil
- Petroni