ArticlePDF Available

Antibacterial Activity of Laurus nobilis: A review of literature

Medical Science and Discovery
2018; 5(11):374-9
Review Article
Doi: 10.17546/msd.482929
Received 15-11-2018 Accepted 20-11-2018 Available Online 21-11-2018 Published 30-11-2018
1 Ondokuz Mayis University, Faculty of Veterinary Medicine, Aquatic Animal Diseases, Kurupelit Campus, Samsun, TR
2 University of Amasya, Faculty of Science, Dept of Biology, Amasya, TR
3 Hakkari University, Faculty of Engineering Dept of Biomedical Engineering, Hakkari, TR
* Corresponding Author: Ayhan Guler E-mail: Phone: +90 (438) 212 12 12
Antibacterial Activity of Laurus nobilis: A review of literature
Belgin Sırıken1, Ceren Yavuz2, Ayhan Güler3*
Antibiotic or multiple antibiotic resistance (MDR)
microorganism particularly pathogen bacteria has
dramatically increased in human and animal. Therefore,
resistance microorganism caused diseases have posed a risk
in human and treated public health. Due to these resistance
properties of microorganism, researchers started looking for
alternative way for treatment or for preventing diseases.
Nowadays, ingredients obtained from plants, like essential
oil, can be used as alternatives to antibiotics. Bay laurel,
cinnamon, oregano and clove like plants have antimicrobial
activity against both some Gram negative and positive
microorganisms (1). In this review, L. nobilis (bay leaf) and
its effects as antimicrobial properties against some
microorganism are highlighted.
Laurel (L.) nobilis (bay leaf) is an aromatic plant and
evergreen tree which belongs to the family of Lauraceae, it
is one of the most widely used culinary spices in all
Western countries and Asian countries.
It is cultivated and endemic in the Mediterranean countries
of Turkey, Spain, Morocco, Greece, Portugal, as well as in
Mexico and other temperate and warm parts of the world.
This aromatic tree is 2 m to 10 m high (2). The plants
inherently cultivated in coastal areas to an altitude of 600-
800 meters. The plant’s leaves and berries are commonly
used as a spice aroma and enhancer for foods especially for
meats, sauces and soups (3). Besides its special aroma, it is
also used to cure diseases all over the world. Some
compounds of this plant such as essential oils and organic
acids have shown strong antibacterial activity against some
foodborne pathogen microorganism besides spoilage
bacteria (4, 3,5,6).
Essential oil is a hydrophobic liquid compartment obtained
from various parts of plant such as flowers, seeds and
stems. Because of its aromatic characteristic, essential oil is
used in as a flavoring agent in cosmetic and food industries
The presence of phenolic compounds in spices and herbs, along with the essential oils, has been gaining attention due to
their various functions like antioxidant capacity, antimicrobial properties, and flavoring properties. The Bay leaf belongs
to Lauraceae family and is endemic in the Mediterranean region. Lauraceae, is an aromatic plant frequently used as a
spice in Mediterranean cookery and as a traditional medicine for the treatment of several infectious disease. L. nobilis
also belongs to Lauraceae. L. nobilis is aromatic tree, and is 2 m to 10 m high. L. nobilis contains about 1.3% essential
oils and polar flavonoids mono, sesquiterpenes, alkoloids, glycosylated flavor-noids, megastigmane and phenolic
components. It is known to have various pharmacological effects, including antimicrobial, cytotoxic and immune
modulating. Its’ essential oil containg eucalyptol, α-terpinyl acetate, linalool, methyl eugenol, sabinene and carvacrol.
The property of every essential oil varies according to the harvest country, altitude, period of sunshine, conditions of
harvest. These essential oil contents of L. nobilis are strong antibacterial activity against Gram negative and Gram
positive foodorne pathogens (Salmonella, Staphylococcus aureus, Esherichia coli, Listeria monocytogenes like that),
spoilage bacteria (Pseudomonas aeroginosa) as well as antifungal effects. The synergy between terpenes (linalool),
lactones, oxides (1,8 cineole) and monoterpenes (camphene, alpa-pinene) gives to the essential oil of Laurel a good
antibacterial activity. Its essential oils’ various or single chemical compositions at different concentrations have differen t
inhibition mechanisms that can affect a variety of pathogens by changing membrane permeability, denaturing proteins
and inhibiting enzymes. The oils are not affecting on existing beneficial intestinal bacteria.
Key words: Essential oils, Laurus nobilis, Antibacterial Activity, Review
Siriken et al.
Medical Science and Discovery, 2018; 5(11):374-9
It has also biologic effects such as antimicrobial,
antidiabetic and anticancer activities (4). The plant’s
essential oils have antimicrobial activity (1). Therefore,
essential oils have been shown to have advantages as
natural antimicrobials. These oils’ various chemical
compositions or single components at different
concentrations have different inhibition mechanisms that
can affect a variety of pathogens by changing membrane
permeability, denaturing proteins and inhibiting enzymes. It
has also shown effective antimicrobial activity against
drug-resistant strains (7).
Essential oil of bay leaves
The property of every essential oil varies according to the
country of harvest, period of sunshine, conditions of
harvest, quality of the distillation, storage and usage (8).
However, it is generally reported that the basic components
of the essential oil of bay leaves are 1.8-cineole, linalool
and a-terpinyl acetate (9).
In addition, it has also some phenolic components such as
epicate-chin, procyanidin dimer, procyanidin trimer,
flavonol and flavonederivatives and many volatile active
components such as a-pinene, ß-pinene, myrcene,
limonene, linalool, methyl chavicol, a-terpineol, geranyl
acetate, eugenol and chavicol. All these compounds are
known as antimicrobial (3,6), anti-oxidant (6), digestive
and anti-cancer and immune modulating (10).
There have been detailed analyses on of essential oil of
obtained from bay leaf. For instance, the GC/MS analysis
reports that, the main components of oil are: an ether-oxide
of terpenic nature: 1.8 cineole or eucalyptol (35.31%),
which is the main component of the essential oil of Bay
leaf, and considered as drug and phenologic stadium of the
Bay leaf. Linalool and camphene are present as
monoterpenes. Sesquiterpenes represented by
sesquiterpenic lactones (cadinene and caryophyllene)
constitute 22% of the oil. Terpinol (3.18%) is predominant
From Turkey, (5) it was reported that the major
components detected in bay laurel essential oil were
eucalyptol (27.2%), α-terpinyl acetate (10.2%), linalool
(8.4%), methyl eugenol (5.4%), sabinene (4.0%) and
carvacrol (3.2%). In Table 1, chemical composition of L.
nobilis essential oil is shown.
Table 1. Chemical compositions of L. nobilis essential oil (3)
Composition (%)
RT: Retention time
Siriken et al.
Medical Science and Discovery, 2018; 5(11):374-9
Antibacterial effects of essential oil of bay leaves
One of the important properties of essential oils and their
components is their hydrophobicity, which allows them to
partition the lipids of the bacterial cell membrane and
mitochondria, disturbing the cell structures and making
them more permeable (11). The antimicrobial activity
depends on not only the chemical composition of the
essential oil, but also on lipophilic properties and power of
functional groups or aqueous solubility. The mixture of
compounds with different biochemical properties can
improve the effectiveness of essential oils (1).
Commonly, essential oil of bay leaves is more effective
against Gram negative bacteria than Gram positive bacteria
(12). This resistance is due to bacterial cellular membranes’
nature group. Hence, their external structures make them to
highly hydrophobic surface 13).
There are some studies according to essential oils of L.
nobilis’ antimicrobial activities. One of them, (13)’s
studies. They report that the essential oil of L. nobilis L.
had demonstrated a strong activity on the majority of tested
22 strains; the highest sensitivity was in Enterobacter
species having an inhibition diameter of 22.4 mm, 16.8 mm
pure oil and 1/8 dilution. The most resistant strain was P.
aeruginosa. They also reported that 1.8 cineole had a part in
this activity having antimicrobial activity against E. coli, P.
aeruginosa and Staphylococcus aureus. Laurel’s essential
oil contains terpenes (linalool), lactones, oxides (1,8
cineole) and monoterpenes (camphene, alpha-pinene).
There is a good synergy among the substances for
antimicrobial activity.
In another study, (14) reported that ampicillin resistant E.
coli was sensitive to the pure oil and diluted at ½, on the
other hand, it was of a weak sensitiveness to the essential
oil diluted at ¼, 1/8, and 1/16. Proteus spp. was resistant to
ampicillin, ticarcillin, cotrimoxazol and chloramphenicol.
This strain showed a very big sensitiveness towards the
pure essential oil but it was resistant to the different used
dilutions. Serratia was resistant to ampicillin, ticarcillin,
ofloxacine and cotrimoxazol. This strain was rather
sensitive to both pure essential oil and different used
dilutions. Klebsiella pneumoniae, Staphylococcus aureus,
Streptococcus D, Pseudomonas aeruginosa and
Acinetobacter, which are resistant to at least one of
antibiotics such as kanamycin, penicillin, nalidixic acid,
lincomicin, cefazolin, imipenem, gentamicin, pefloxacin,
phosphomycin and piperacillin. But They are susceptible to
essential fatty acids diluted 1/2 and at 1/4 (6)’s study aimed
to evaluate the antimicrobial and antioxidant activities of
essential oils obtained from bay laurel, white wormwood
and rose-scented geranium against Salmonella typhimurium
and Escherichia coli O157:H7 on fresh produce and to
examine consumer acceptability of fresh produce treated
with these essential oils. Bay laurel’s essential oil consisted
of 30-50% 1.8-cineol, 10-20% linalool, 2.13% methyl
eugenol and 0.01% eugenol. They found that while
essential oil derived from rose-scented granium exhibited
the most effective antimicrobial activity, the highest
activity was occurred in bay laurel essential oil.
From Turkey, (3) has obtained essential oil from leaves of
Laurus nobilis using extraction technique. After extraction,
they found that the main components of oil were 51.8%
1,8-cineole, 11.2% α-terpinyl acetate, and 10.1% sabinene.
They also found that the L. nobilis essential oil was of the
high antibacterial, antifungal and antioxidant potential.
(5) reported that natural extracts from myrtle and laurel can
be used by the food industry to extent the shelf life of
seafood because they exhibited promising antioxidant and
antimicrobial effects. (15)’s study results also showed that
1% thyme essential oil treatment was effective in inhibiting
spoilage bacteria growth in the iced storage fish. They also
obtained same results in treatment of laurel essential oil. In
addition, two plant’s essention oil had positive effects on
shelf life of iced stored fish samples.
Nano- particules of Laurus nobilis (Ln-ZnO NPs) and
antimicrobial effects
Nanoparticles have widely emerged as an anti-bacterial
agent in the last decade. It has particularly showed specific
targeting and minimum toxicity. They have proven useful
for inhibiting antibiotic-resistant bacteria particularly
Nanoparticles are in the size ranges from 10-100 nm. The
appearance and usefulness of nanoparticles brings many
advantages and opportunities. These nanoparticles can be
synthesized by physical, chemical and biological methods.
In the course of time several groups have achieved success
in the synthesis of silver, titanium oxide, copper oxide, iron
oxide, zinc oxide (ZnO) and gold etc. Because of the fact
that nano particles significatly inhibit growth of many type
microorganisms, many researchers have been interested to
develop many applications. There are very kinds of
nanoparticles. Among them, silver nanoparticules are more
common than others. Silver and their compounds have
highly antmicrobial effects on microorgaisms such as
Escherichia coli and Staphylococcus aureus (16). It has
long-lasting biocide and low volatility. In contrast, it has
low toxicity to human cells (17). Beside silver, zinc oxide
nanoparticules have more inhibitory effects on
micriorganisms than silver nanoparticules. Hence, its small
size and high surface-to-volume ratio of zinc oxide
nanoparticles allow for better interaction with bacteria
(18)., So zinc oxide nanoparticle is highly biocompatible
and its electron transport kinetics rate is fast and, it's it is
suitable to be used as a biological membrane or for other
biological applications (19). The nanoparticles have
selective toxicity to both Gram-positive and Gram-negative
bacteria such as E. coli O157:H7, Salmonella, Listeria
monocytogenes, and Staphylococcus aureus and
Streptococcus pyogenes, Escherichia coli, Klebsiella
aerogenes, Pseudomonas aeruginosa, Proteus mirabilis,
Mycobacterium tuberculosis and Bacillus subtilis (figure
1). For reduction and stabilization of nanoparticle,
phytochemicals are used. These phytochemicals may
contribute to the anti-bacterial activity of nanoparticles by
starting a cascade of events like ROS generation, disrupting
the bio film formation, cell membrane integrity disruption,
enzyme inhibition, protein denaturation, or by accelerating
the process (Figure 2) (20, 19).
Siriken et al.
Medical Science and Discovery, 2018; 5(11):374-9
Silver, zinc oxide, gold and palladium nanoparticles using
extracts obtained from unicellular organisms like bacteria
(21,25) and fungi, as well as extracts from plant parts, e.g.,
geranium leaves, Bay leaf (Laurus nobilis), neem leaves,
lemon grass, aloe Vera and several others (22). Green
synthesized nanoparticles surround themselves with a large
group of organic phytochemicals which helps in ligand-
based complexation with various receptors like proteins,
lipid, phospholipid, lipoteichoic acid at the microbial
This complexation of nanoparticle with bacteria prevents
biofilm formation and their growth (23).
Nanoparticles synthesized by green route tend to exhibit
better anti-bacterial activity than physical or chemical
method derived nanoparticles due to the coating of various
pharmacologically active biomolecules on their surface
which allows multiple ligands based conjugation of
nanoparticle with receptors on bacterial membranes.
Figure 1. ZnO- NPs interaction with Gram positive and negative cell (19).
Figure 2. Anti-bacterial mechanisms of ZnO- NPs (19)
Siriken et al.
Medical Science and Discovery, 2018; 5(11):374-9
These biomolecules are mainly organic acids, flavones,
aldehyde, ketone, amides, polysaccharides, and quinones
and known to have significant therapeutic effect against a
wide range of human pathogen (24).
Nanoparticuls obtained from L. nobilis have antibacterial
activity against microorganisms. (22) conducted a study. In
this study, they obtained the green synthesis of zinc oxide
( nanoparticles using the aqueous leaf extract of Laurus
nobilis (Ln-ZnO NPs) by co-precipitation method. They
found that the antibacterial activity of Ln-ZnO NPs was
greater against Gram positive (Staphylococcus aureus)
bacteria than Gram negative (Pseudomonas aeruginosa)
bacteria. In addition to this, the light and confocal laser
scanning microscopic images gave evidence that Ln-ZnO
NPs effectively inhibited the biofilm growth of S. aureus
and P. aeruginosa at 75mg mL1.
Mainly essential oil of Laurus nobilis has strong
antibacterial activity against Gram negative and Gram
positive foodorne pathogens, spoilage bacteria as well as
antifungal effects. Use of nanoparticles as an antibacterial
agent in current studies with metal nanoparticles like silver,
gold, copper, iron and metal oxide nanoparticles like zinc
oxide etc, it has not been common. Laurus nobilis origin
zinc oxide nanoparticules (Ln-ZnO NPs) have antibacterial
activity especially against Gram positive bacteria. Drug
made from plants and nanoparticles are alternative
approaches to spoilage due to potoogens and
Acknowledgement: None.
Conflict of Interest: The authors declare no potential
conflicts of interest with respect to the research, authorship,
and/or publication of this article.
Author’s Contributions: BS, CY, AG; Review literature,
planning and design of research AG; preparing article and
Ethical issues: All Authors declare, Originality and ethical
approval of research. Responsibilities of research,
responsibilities against local ethics commission are under
the Authors responsibilities.
1. Dorman HJ1, Deans SG. Antimicrobial agents from plants:
antibacterial activity of plant volatile oils.J Appl Microbiol.2000.
2. Dall’Acqua S, Viola G, Giorgetti M, Loi MC, Innocenti G. Two new
sesquiterpene lactones from the leaves of Laurus nobilis. Chem.
Pharm. Bull. 2006. 54:1187-1189.
3. Yılmaz EY, Timur M, Aslim B. Antimicrobial, Antioxidant Activity
of the Essential Oil of Bay Laurel from Hatay, Turkey. TEOP 16 (1)
2013 pp 108 116.
4. Bakkali, F.; Averbeck, S.; Averbeck, D.; Idaomar, M. Biological
effects of essential oilsA review. Food Chem. Toxicol.,2008. 46,
5. Ozogul I, Polat A, Ozogul Y, Boga EK, Ayas D. Effects of laurel
and myrtle extracts on the sensory, chemical and microbiological
properties of vacuum-packed and refrigerated European eel
(Anguilla anguilla) fillets. International Journal of food Science and
Technology,2013. Doi :10.1111/ijfs.12374
6. Rafiq R, Hayek SA, Anyanwu U, Hardy BI, Giddings VL,Ibrahim
SA, Tahergorabi R, Won Kang H. Antibacterial and Antioxidant
Activities of Essential Oils from Artemisia herba-alba Asso.,
Pelargonium capitatum × radens and Laurus nobilis L.Foods, 2016.
7. Nazzaro F, Fratianni F, De Martino L, Coppola R, De Feo V. Effect
of essential oils on pathogenic bacteria. Pharmaceuticals
(Basel),2013. 6(12): 1451-74.
8. Benoit SG, , Saint Gir FT, The Choice of Essential Oils, Health,
Beauty and Well-Being by the Aromatherapy, Jouvence Ed., France,
9. Santos AF, Brotto DF, Favarin LRV, Cabeza NA, Andrade GR,
Batistote M, et al. Study of the antimicrobial activity of metal
complexes and their ligands through bioassays applied to plant
extracts. Rev Bras Farmacogn 2014. 24(3): 309-15.
10. Park HJ, Jung WT, Basnet P, Kadota S, Namba T Syringin 4-
Obglucoside, a new phenylpropanoid glycoside, and costunolide, a
nitric oxide synthase inhibitor, from the stem bark of Magnolia
sieboldii. J. Nat. Prod.1996. 59:1128-1130.
11. Sikkema J, De Bont JAM, Poolman B Interactions of cyclic
hydrocarbons with biological membranes. J. Biol. Chem.1994.
269:8022- 8028.
12. Loäpez P, Saänchez C, Batlle R, Neriän C. Solid- and VaporPhase
Antimicrobial Activities of Six Essential Oils:  Susceptibility of
Selected Foodborne Bacterial and Fungal Strains. J. Agric. Food
Chem. 2005. 53(17):6939-6946
13. Ouibrahim A, Tlili-Ait-Kaki Y, Bennadja S, Amrouni S, Djahoudi
AG, Djebar MR. Evaluation of antibacterial activity of Laurus
nobilis L., Rosmarinus officinalis L. and Ocimum basilicum L. from
Northeast of Algeria. African journal of microbiology research 2013.
,7(42): 4968-4973.
14. Bennadja S, Thili Ait Kaki Y, Djahoudi A, Hadef Y,Chefrour A.
Antibiotic Activity of the Essential Oil of Laurel (Laurus nobilis L.)
on Eight Bacterial Strains. Journal of Life Sciences, 2013. 7 (8):
15. Erkan, N., Tosun, S.Y., Ulusoy, S. & Uretener, G. The use of
thyme and laurel essential oil treatments to extend the shelf life of
bluefish (Pomatomus saltatrix) during storage in ice. Journal fur€
Verbraucherschutz und Lebensmittelsicherheit, 2011. 6, 3948.
16. Sambhy V, MacBride, M. M, Peterson, B. R, Sen A. 2006. Silver
bromide nanoparticle/polymer composites: dual action tunable
antimicrobial materials. J Am Chem Soc, 2: 9798-9808.
17. Williams RL, Doherty PJ, Vince DG, Grashoff GJ, Williams D.F.
The biocompatibility of silver. Crit. Rev .Biocompat, 1989. 5:221
18. Reddy KM, Feris K, Bell J, Wingett DG, Hanley C, Punnoose A.
Selective toxicity of zinc oxide nanoparticles to prokaryotic and
eukaryotic systems. Appl. Phys. Lett. 2007. 90, 213902- 1213902-3
19. Agarwal H, Menon S, Kumar S, Rajeshkumar S. .Mechanistic study
on antibacterial action of zinc oxide nanoparticles synthesized using
green route. Chemico-Biological Interactions, 2018.286: 60-70.
20. Cowan M.M. Plant products as antimicrobial agents. Clin Microbiol
Rev., 1999 12: 564-582.
Siriken et al.
Medical Science and Discovery, 2018; 5(11):374-9
21. Ahmad, A.; Senapati, S.; Khan, M. I.; Kumar, R; Sastry, M.
Extracellular Biosynthesis of Monodisperse Gold Nanoparticles by a
Novel Extremophilic Actinomycete, Thermomonospora sp.
Langmuir. 2003. 19, 35503553.
22. Vijayakumar S, Vaseeharan B, Malaikozhundan B, Shobiya M.
Laurus nobilis leaf extract mediated green synthesis of ZnO
nanoparticles: Characterization and biomedical applications.
Biomedicine & Pharmacotherapy. 2016. 84 12131222
23. Puzyn T.; Leszczynski J.; Cronin M.T.D. Recent Advances in QSAR
Studies: Methods and Applications, Springer. 2010.
24. Mukherjee, P.; Senapati, S.; Mandal, D.; Ahmad, A.; Khan, M. I.;
Kumar, R.; Sastry, M. Extracellular synthesis of gold nanoparticles
by the fungus Fusarium oxysporum. Chem Bio Chem., 2002. 3,
461- 463.
25. Hahverdi AR, Minaeian S, Shahverdi HR, Jamalifar H, Nohi AA.
Rapid synthesis of silver nanoparticles using culture supernatants of
Enterobacteria: A novel biological approach. Process
09oCopyright © 2018 The Author(s); This is an open-access article distributed under the terms of the Creative Commons Attribution License
(, which permits unrestricted use, distribution, and reproduction in any medium, p rovided the original
work is properly cited. All Rights reserved by international journal of Medical Science and Discovery.
... Some studies reported the biological activities of L. nobilis extracts as well as L. nobilis essential oils (EOs); for instance, Sakran et al. [2] revealed the antimicrobial activities of an ethanol extract of L. nobilis against Escherichia coli, Salmonellae typhi, and Staphylococcus aureus, with different levels of inhibition zones and minimum inhibitory concentrations (MICs). The antifungal and antioxidant activities of L. nobilis flower EOs were documented [3,4]. ...
... Other previous studies reported that L. nobilis extract was utilized as an additive in cosmetic and food products due to the existence of aromatic and flavor constituents [8,9]. Pharmacological effects such as immune-modulating and cytotoxic effects were also attributed to L. nobilis extract [3]. The activity of L. nobilis extract may depend on several factors, such as the extracted organ of the plant and the used solvent. ...
Full-text available
It is worth noting that laurel (Laurus nobilis L.) contains several pharmacologically and nutritionally active compounds that may differ according to the pretreatment process. The current study is designed to clarify the effect of moist heat on the phenolic and flavonoid constituents and anti-Helicobacter pylori, antioxidant, antidiabetic, and anti-Alzheimer’s activities of laurel leaf extract (LLE). Unmoist-heated (UMH) and moist-heated (MH) LLEs showed the presence of numerous flavonoid and phenolic constituents, although at different levels of concentration. MH significantly induced (p < 0.05) the occurrence of most compounds at high concentrations of 5655.89 µg/mL, 3967.65 µg/mL, 224.80 µg/mL, 887.83 µg/mL, 2979.14 µg/mL, 203.02 µg/mL, 284.65 µg/mL, 1893.66 µg/mL, and 187.88 µg/mL, unlike the detection at low concentrations of 3461.19 µg/mL, 196.96 µg/mL, 664.12 µg/mL, 2835.09 µg/mL, 153.26 µg/mL, 254.43 µg/mL, 1605.00 µg/mL, 4486.02 µg/mL, and 195.60 µg/mL using UMH, for naringenin, methyl gallate, caffeic acid, rutin, ellagic acid, coumaric acid, vanillin, ferulic acid, and hesperetin, respectively. Chlorogenic acid, syringic acid, and daidzein were detected in the UMH LLE but not in the MH LLE, unlike pyrocatechol. The anti-H. pylori activity of the UMH LLE was lower (23.67 ± 0.58 mm of inhibition zone) than that of the MH LLE (26.00 ± 0.0 mm of inhibition zone). Moreover, the values of MIC and MBC associated with the MH LLE were very low compared to those of the UMH LLE. Via MBC/MIC index calculation, the UMH and MH LLEs showed cidal activity. The MH LLE exhibited higher anti-biofilm activity (93.73%) compared to the anti-biofilm activity (87.75%) of the MH LLE against H. pylori. The urease inhibition percentage was more affected in the UMH LLE compared to the MH LLE, with significant (p < 0.05) IC50 values of 34.17 µg/mL and 91.11 µg/mL, respectively. Promising antioxidant activity was documented with a very low value of IC50 (3.45 µg/mL) for the MH LLE compared to the IC50 value of 4.69 µg/mL for the UMH LLE and the IC50 value of 4.43 µg/mL for ascorbic acid. The MH LLE showed significantly higher (p < 0.05) inhibition of α-glucosidase and butyrylcholinesterase activities, with IC50 values of 9.9 µg/mL and 17.3 µg/mL, respectively, compared to those of the UMH LLE at 18.36 µg/mL and 28.92 µg/mL. The molecular docking of naringenin showed good docking scores against acetylcholinesterase 1E66 and butyrylcholinesterase 6EMI, indicating that naringenin is an intriguing candidate for additional research as a possible medication for Alzheimer’s disease.
... ‫العراقية‬ ‫الزراعية‬ ‫العلوم‬ ‫مجلة‬ (28). It's an aromatic evergreen shrub or tree that regarded as high-content spice found in Europe, South America, Asia, and endemic in Morocco, Spain &Turkey (13). ...
... Antibacterial activity of Laurus nobilis leaves water extract was detected against grampositive bacteria like Listeria monocytogenes, S. aureus & gram-negative bacteria such as E. coli, P. aeruginosa, K. pneumoniae & Enterobacter cloacae. Results revealed that the average of inhibition zone of leaves water extract against M.O. was ranged from (18-25) mm for P. aeruginosa, K. pneumoniae(14)(15)(16)(17)(18)(19)(20) mm, S aureus (12-15) mm, Enterobacter cloacae (10-13) mm(28). Results in this study was agreed with that reported by(8)because various agents, such as the season, variance in the plant components &the Essential oils variations within a plant spp. ...
Full-text available
This study was aimed to isolation of pathogenic bacteria from different clinical cases like burns, wounds &UTI infections, then study the antimicrobial activity of Laurus nobilis leaves water extract on it. From a total of (80) samples were taken from these cases, the most isolated bacteria were related to Pseudomonas aeruginosa, Klebsiella pneumoniae, Staph aureus & Escherichia coli. Antibiotic sensitivity test was done for isolated bacteria against (9) antibiotic and most of them revealed sensitivity to gentamycin, ciprofloxacin& trimethoprim/ sulphamethoxazole. Different concentration of Laurus nobilis leaves water extract (25, 50, 100, 200) mg/ml were tested for detection its antibacterial activity against isolated bacteria .Results revealed that concentration (50, 100, 200) mg/ml revealed high antibacterial activity against Staph aureus & Klebsiella pneumoniae, also showed intermediate level against Escherichia coli, while higher concentration only (100, 200) mg/ml of extract revealed antibacterial activity against Pseudomonas aeruginosa
... The fact that Laurus nobilis plant displays biological activity sets it apart the most from plant others (Begum et al., 2013). It is associated with its extract and essential oils as an antifungal agent (Caputo et al., 2017), an antiviral agent, an antibacterial agent (Simić et al., 2004), an acaricidal agent (Sırıken et al., 2018) and an insecticidal agent (Fernandez et al., 2020). Knowledge of the disposal methods for helminths infected by plant extracts in laboratory animals is essential because parasites may act as variables affecting experimental outcomes. ...
Full-text available
Background: The safety of laboratory mice plays an important role in the success of laboratory experiments for correct and accurate results. Parasites are one of the most common diseases that affect most organisms. The worm Aspiculuris tetraptera is a common intestinal parasite of Mus musculus and rats, it is spread around the world. Aspiculuris tetraptera infection remains a problem for modern research groups; They should be excluded and monitored in rat populations due to their effects on animal health. Methods: The present study was conducted to assess the anthelmintic activity of Laurus nobilis extract in mice naturally infected with Aspiculuris tetraptera. Used was Thirty-six adult male and female (C57BL/6) mice, naturally infected with Aspiculuris tetraptera, were divided into six groups, each comprising six mice: Group 1, was the negative control (infected, untreated), and Groups 2, 3, 4, and 5 were treated with 50, 100, 200 and 400 ìg/ml of L. nobilis for 5 days respectively. Group 6 was treated with 10 mg/mL Albendazole for 3 days as a positive control. Different six treatments were used to test Aspiculuris tetraptera worms in vitro, Containing 4 concentrations (50, 100, 200 and 400 mg/ml) of L. nobilis extract. Ten actively moving adult worms were then placed in each petri dish at room temperature. A saline solution and 10 mg/ml of Albendazole were prepared and used as negative and positive controls. After treatment, observations were made by recording the death time for worms at 20, 40, 80, 120 and 180 minutes. Worms are considered dead if they do not move for 30 seconds after touching their body parts using a surgical needle and the petri dish is shaken. Result: The analysis of phytochemicals by FT-IR for alcoholic extracts of L. nobilis extracts revealed the presence of 15% effective chemical ingredients responsible for killing worms’ activity. In vitro, worms died in 20, 40, 80, 120 and 180 minutes. Attained 96% and 100% after 180 minutes at the highest concentrations (200 and 400 mg/ml). At the same time, the untreated group lasted for long hours. The effects of the plant extract (Laurus nobilis) on Aspiculuris tetraptera worms were studied in vivo at therapeutic doses of 50, 100, 200 and 400 mg/mL. and the concentration of 400 ml/kg showed the most lethal effects for worms, infected mice that did not receive drugs were compared with the highest concentration of the extract and the reference treatment. The attention showed significant differences P≤0.05. The results showed that the mortality rate of worms taken from the intestines of the treated mice that were slaughtered three and six sdays after giving the treatment reached 96% and 100% in the concentration of 400 ml/kg of the extract and 89% and 97%for the mice that treated in 10 ml/kg of met Albendazole respectively. This research showed that herbal remedies could lead to new parasitic disease drugs, and their derivatives can be used for medication production and bioactivity improvement.
... Laurel, also known as bay leaf, is an aromatic evergreen shrub from the Lauraceae family. It is scientifically known as Laurus nobilis and is native to the Mediterranean coast (Parthasarathy et al., 2008;Ross, 2001;Siriken et al., 2018). Commonly known as an ingredient or spices in Mediterranean and Southeast Asian cuisines, laurel is also well known for their medicinal properties (Bianchi, 2015). ...
The erroneous assumption that herbal products is generally safe for consumption, is a major factor leading to the increased of herb-induced liver injury (HILI). Even though Laurus nobilis or laurel is a commonly used spice, the safety aspect for its consumption is under-studied. To bridge this gap of knowledge, the mutagenicity, acute toxicity, and subacute toxicity of LAURESH®, which is a standardized laurel leaf extract were evaluated. Mutagenicity study using two S. typhimurium strains, TA100 and TA98 indicated that LAURESH® does not cause base substitution and frameshift mutation, thus suggesting that LAURESH® is non-mutagenic. While acute oral toxicity on mice established the LD50 at no less than 2,000 mg/kg of body weight, and a 28-day subacute toxicity test on rat revealed the NOAEL to be 1,000 mg/kg/day. Furthermore, blood chemistry, urinalysis, necropsy, and histopathological data from subacute toxicity study on rats does not show adverse event that could be attributed to LAURESH®, thus indicating that LAURESH® is unlikely to cause HILI. Taken together, the findings from this study and previous clinical study on LAURESH®, in combination with the historic use of laurel and previous toxicity studies conducted on laurel leaves extract, strongly suggest that LAURESH® is safe for human consumption.
... Overall, the findings of our current investigation are consistent with those of previous publications using the diffusion method that showed potent broad-spectrum antibacterial ability [116,117]. It is claimed that the mode of action of the EOs against target microorganisms is different from the regular antibiotics; when exposed to EOs, bacterial cells might be destroyed by the irregular disruption of the intracellular structure and the bursting of cell walls and membranes [105]. ...
Full-text available
The objectives of this work were to determine the phytochemical composition and an�tioxidant, anti-diabetic, antibacterial, anti-inflammatory, and anti-acetylcholinesterase properties of Arbutus unedo L. and Laurus nobilis L. EOs. The antioxidant effects were estimated using four comple�mentary methods. In addition, the anti-diabetic activity was assessed by targeting three carbohydrate�hydrolyzing enzymes, namely α-amylase, α-glucosidase, and lipase. The anti-inflammatory and anti-acetylcholinesterase effects were evaluated by testing the inhibitory potential of both plants on lipo-oxygenase and acetylcholinesterase (AChE), respectively. The antimicrobial activity of these oils was evaluated using disc-diffusion, minimum inhibitory concentration (MIC), and minimum lethal concentration (MLC) tests. The chemical composition of L. nobilis essential oil (EO) was dominated by eucalyptol (36.40%), followed by α-terpineole (13.05%), α-terpinyl acetate (10.61%), linalool (10.34%), and northujane (5.74%). The main volatile compounds of A. unedo EOs were decenal (13.47%), α-terpineol (7.8%), and palmitic acid (6.00%). L. nobilis and A. unedo EOs inhibited α-amylase with IC50 values of 42.51 ± 0.012 and 102 ± 0.06 µg/mL, respectively. Moreover, both oils inhibited the activity of α-glucosidase (IC50 = 1.347 ± 0.021 µg/mL and IC50 = 76 ± 0.021 µg/mL) and lipase (IC50 = 21.23 ± 0.021 µg/mL and IC50 = 97.018 ± 0.012 µg/mL, respectively). In addition, L. nobilis EO showed an anti-AChE activity (IC50 = 89.44 ± 0.07 µg/mL) higher than that of A. unedo EO (IC50 = 378.57 ± 0.05 µg/mL). Regarding anti-inflammatory activity, in vitro assays showed that L. nobilis significantly inhibits (IC50 = 48.31 ± 0.07 µg/mL) 5-lipoxygenase compared to A. unedo (IC50 = 86.14 ± 0.05 µg/mL). This was confirmed in vivo via a notable inhibition of inflammation recorded after 6 h of treatment in both plants at a dose of 50 mg/kg. The microbiological results revealed that EOs from both plants inhibited the growth of all tested organisms except P. aerugi�nosa, with the highest antimicrobial effect for L. nobilis. The results of these tests showed that these two plants possess remarkable biological and pharmacological properties, explaining their medicinal effects and suggesting them as promising sources of natural drugs.
... The greater antibacterial activity has been found in Laurus essential oil in comparison with tetracycline antibiotics [212]. It is reported that bay leave essential oil can alter membrane-embedded proteins, damage cellular membranes, enhance the permeability of the membrane, damage the transit system of the membrane [868]. The EO showed antibacterial properties may be due to the presence of terpenes. ...
Full-text available
Medicinal or herbal spices are grown in tropical moist evergreen forestland, surrounding most of the tropical and subtropical regions of Eastern Himalayas in India (Sikkim, Darjeeling regions), Bhutan, Nepal, Pakistan, Iran, Afghanistan, a few Central Asian countries, Middle East, USA, Europe, South East Asia, Japan, Malaysia, and Indonesia. According to the cultivation region surrounded, economic value, and vogue, these spices can be classified into major, minor, and colored tropical spices. In total, 24 tropical spices and herbs (cardamom, black jeera, fennel, poppy, coriander, fenugreek, bay leaves, clove, chili, cassia bark, black pepper, nutmeg, black mustard, turmeric, saffron, star anise, onion, dill, asafoetida, celery, allspice, kokum, greater galangal, and sweet flag) are described in this review. These spices show many pharmacological activities like anti-inflammatory, antimicrobial, anti-diabetic, anti-obesity, cardiovascular, gastrointestinal, central nervous system, and antioxidant activities. Numerous bioactive compounds are present in these selected spices, such as 1,8-cineole, monoterpene hydrocarbons, γ-terpinene, cuminaldehyde, trans-anethole, fenchone, estragole, benzylisoquinoline alkaloids, eugenol, cinnamaldehyde, piperine, linalool, malabaricone C, safrole, myristicin, elemicin, sinigrin, curcumin, bidemethoxycurcumin, dimethoxycurcumin, crocin, picrocrocin, quercetin, quercetin 4’-O-β-glucoside, apiol, carvone, limonene, α-phellandrene, galactomannan, rosmarinic acid, limonene, capsaicinoids, eugenol, garcinol, and α-asarone. Other than that, various spices are used to synthesize different types of metal-based and polymer-based nanoparticles like zinc oxide, gold, silver, selenium, silica, and chitosan nanoparticles which provide beneficial health effects such as antioxidant, anti-carcinogenic, anti-diabetic, enzyme retardation effect, and antimicrobial activity. The nanoparticles can also be used in environmental pollution management like dye decolorization and in chemical industries to enhance the rate of reaction by the use of catalytic activity of the nanoparticles. The nutritional value, phytochemical properties, health advantages, and both traditional and modern applications of these spices, along with their functions in food fortification, have been thoroughly discussed in this review
Full-text available
Tıbbi aromatik bitkiler binlerce yıldır ilaçların ana kaynağı ve sistematik geleneksel ilaçların temeli olarak kullanılmaktadır. Tıbbi aromatik bitkiler arasında çeşitli hastalıkların tedavisinde en yaygın kullanılan bitkilerden birisi Asteraceae familyasında bulunan Achillea sp. türleridir. Achillea türlerinin en bilinen bitkisi A. millefolium’dur. A. millefolium çeşitli cilt rahatsızlıklarını ve sindirim bozukluklarını tedavi etmek için kullanılır. Tıbbi kullanımlarına ilaveten kozmetik ve veterinerlik alanında da kullanılmaktadır. Monoterpen 1,8-sineol iyi bilinen bir terpenoit oksittir ve ayrıca klinik etki için ilgili bir anlamı olan diğer uçucu yağların bileşenidir. Anti-inflamatuar, antioksidan, serbest radikal süpürücü, mukolitik/sekretolitik, bronkodilatör, antiviral ve antimikrobiyal etkileri de dâhil olmak üzere birçok biyolojik aktivitesi bilinmektedir. Bu çalışma, Sivas’ta yetişen Achillea millefolium (civanperçemi) bitkisinin uçucu yağ bileşimi miktarını değerlendirmek amacıyla yapılmıştır. Çalışmada bitkinin uçucu yağ içeriği tespit edilmiş ve 1,8-sineol (%19.33) bileşiğinin Achillea millefolium bitkisinde bulunan diğer uçucu yağlardan yüksek olduğu belirlenmiştir. Çalışmalarda, bitki uçucu yağı analizi için Gaz Kromatografisi (GC-MS) kullanılmıştır. Bitkide, baskın olarak 15 adet uçucu yağ bileşeni belirlenmiştir ve yazımızda detaylı olarak sunulmuştur. Ayrıca, bitki uçucu yağının antimikrobiyal ve antifungal özelliği belirlenmiştir. Escherichia coli, Staphylococcus aureus, Salmonella typhimurium türlerinin inhibisyon çapları sırası ile 0.891, 0.763 ve 0.529 mm olarak bulunmuştur. Benzer şekilde, Aspergillus flavus, Fusarium solani ve Penicillium digitatum karşı uçucu yağın engelleme oranı sırasıyla %34.91, %21.47 ve %23.08 olarak bulunmuştur.
The aim of this study was to the production of an active film based on Prangos ferulacea root gum, using its leaf's essential oil (PFEO) (0-3 %) and bismuth oxide nanoparticles (Bi2O3NPs) (0-3 %). Then, the developed film was used for packaging of quail fillet. Response surface methodology was used to evaluate the effect of PFEO and Bi2O3NPs on films' properties. Optimum formulation, including 1.5 % PFEO and 1 % Bi2O3NPs, was achieved based on numerical optimization. The optimum film was produced and compared with the control film (based on Prangos ferulacea root gum, without PFEO and Bi2O3NPs). According to the results, adding PFEO and Bi2O3NPs to the film formulation increased the thickness and antioxidant activity of the film and decreased moisture content, solubility, water vapor permeability, and whiteness index (p < 0.05). The optimum film indicated high antimicrobial effects on Escherichia coli and Staphylococcus aureus. The pH, TVBN, TBA values, coliform, and total bacterial counts of quail fillet packed with the optimum film were lower and sensorial scores were higher than the control samples during the storage(p < 0.05).
Background: Ticks are destructive ectoparasites that feed on the blood of domestic animals and the spread of ticks causes significant losses in meat, milk and leather production. About 800 species of ticks are known around the world, Hyalomma dromedarii is one of the ticks that attack camels as their main host. The objective of this study was to identify the acaricidal activity of Laurus nobilis and Croton tiglium seeds extract against H. dromedarii ticks and comparison with some drugs used against external parasites. Methods: A study was performed to evaluate the acaricidal activities of methanolic extracts of two medicinal plants, namely the seeds of C. tiglium and L. nobilis, against H. dromedarii using an adult immersion test and larval bundle test. Five graduated concentrations of extracts, 6.25, 12.5, 25, 50 and 100 mg/ml, were tested at different periods and changes over time in the viability of ticks were registered for 24 hr. Distilled water and cypermethrin (0.1%) were used as a negative and positive control, respectively. Result: From 30 min after exposure, a concentration of 100 mg/ml of C. tiglium seed extract resulted in higher mortality (p less than 0.05) compared with cypermethrin. A significant rise in tick mortality began 2 hr after exposure to a concentration of 100 mg/ml of C. tiglium seed extract and cypermethrin. At 24 hr after exposure, cypermethrin and concentrations of 50 and 100 mg/ml of C. tiglium extract induced significantly higher tick mortality compared to the rest of the concentrations. A significant increase in tick mortality began 3 hr after exposure to cypermethrin and concentrations of 50 and 100 mg/ml of Laurus nobilis extract and 12 hr after exposure to concentrations of 6.25, 12.5 and 25 mg/ml L. nobilis extract. At 24 hr after the exposure time, concentrations of 50 and 100 mg/ml of the extract and cypermethrin had a comparable higher tick mortality effect compared to the remaining concentrations below 25 mg/ml (p less than 0.05). The lower concentration (6.25 mg/ml) resulted in notably higher mortality of adult ticks and larvae compared to the negative control (distilled water) at 24 hr exposure to both extracts. At 24 hr after the exposure period, the tick mortality of all estimated plant extracts also increased with raised exposure time and concentration. Therefore, studied plants can be used against H. dromedarii as a potential alternative to commercially available medicines. Further studies should include more research on separating each component and validating the materials.
Full-text available
Essential oils are natural antimicrobials that have the potential to provide a safer alternative to synthetic antimicrobials currently used in the food industry. Therefore, the aim of this study was to evaluate the antimicrobial and antioxidant activities of essential oils from white wormwood, rose-scented geranium and bay laurel against Salmonella typhimurium and Escherichia coli O157:H7 on fresh produce and to examine consumer acceptability of fresh produce treated with these essential oils. Our results showed that essential oil derived from rose-scented geranium exhibited the most effective antimicrobial activity at the same and similar minimum inhibition concentration levels (0.4%, v/v and 0.4% and 0.5%, v/v) respectively against Salmonella typhimurium and Escherichia coli O157:H7. All three essential oils showed antioxidant properties, with the highest activity occurring in bay laurel essential oil. In a sensory test, tomatoes, cantaloupe and spinach sprayed with 0.4% rose-scented geranium essential oil received higher scores by panelists. In conclusion, rose-scented geranium essential oil could be developed into a natural antimicrobial to prevent contamination of Salmonella typhimurium and Escherichia coli O157:H7 in fresh produce, plus this oil would provide additional health benefits due to the antioxidant properties of its residue.
Full-text available
Many cyclic hydrocarbons, e.g. aromatics, cycloalkanes, and terpenes, are toxic to microorganisms. The primary site of the toxic action is probably the cytoplasmic membrane, but the mechanism of the toxicity is still poorly understood. The effects of cyclic hydrocarbons were studied in liposomes prepared from Escherichia coli phospholipids. The membrane-buffer partition coefficients of the cyclic hydrocarbons revealed that these lipophilic compounds preferentially reside in the membrane. The partition coefficients closely correlated with the partition coefficients of these compounds in a standard octanol-water system. The accumulation of hydro carbon molecules resulted in swelling of the membrane bilayer, as assessed by the release of fluorescence self-quenching of fluorescent fatty acid and phospholipid analogs. Parallel to the expansion of the membrane, an increase in membrane fluidity was observed. These effects on the integrity of the membrane caused an increased passive flux of protons and carboxyfluorescein. In cytochrome c oxidase containing proteoliposomes, both components of the proton motive force, the pH gradient and the electrical potential, were dissipated with increasing concentrations of cyclic hydrocarbons. The dissipating effect was primarily the result of an increased permeability of the membrane for protons (ions). At higher concentrations, cytochrome c oxidase was also inactivated. The effective concentrations of the different cyclic hydrocarbons correlated with their partition coefficients between the membrane and aqueous phase. The impairment of microbial activity by the cyclic hydrocarbons most likely results from hydrophobic interaction with the membrane, which affects the functioning of the membrane and membrane-embedded proteins.
Full-text available
The appearance of resistant bacteria was found to reduce the efficiency of antimicrobial therapies with the current antibiotics, thereby increasing the need for more efficient drugs for the treatment of infections. Several studies have demonstrated an increase in antimicrobial activity following the interaction of several compounds with metal ions. The present study used a methodology adapted for antimicrobial bioassays using plant extracts, in compliance with the standards of the Clinical and Laboratory Standards Institute against Gram-positive and Gram-negative bacteria. The results obtained were considered appropriate for determining MIC, MBC as for performing antimicrobial sensitivity testing with good efficiency and reproducibility. The bacteria Pseudomonas fluorescens exhibited high sensitivity to the tested compounds, being efficient to evaluate the antibacterial activity. The bioassays with the metal complexes of flavonoid quercetin and Ga(III) ions, and synthetic ligand H2bbppd and Cu(II) ions showed a greater inhibitory effect than their individual ligands, thus, the addition indicated an increase in the antimicrobial activity after the coordination. Both metal complexes exhibit good antimicrobial performances, such as low minimum inhibitory concentration (MIC ≤ 250 μg/ml), bactericidal effect and a broad activity spectrum, which qualify these compounds as suitable candidates to the next step of drugs fabrication. Nevertheless, further studies on the mechanism of growth inhibition and toxicity are needed, in order to evaluate the potential of therapeutic application.
Full-text available
Abstract: The recent studies unveil more and more therapeutic properties of the essential oil of Bay leaf (Laurus nobilis L.). The aim of this study is to determine the chromatographic profile of the essential oil of Bay leaf cultivated under the climatic conditions of the Algerian East and to test its antibiotic activity, against 8 bacterial strains (Escherichia coli, Serratia sp., Proteus sp., Klebsiella pneumoniae, Staphylococcus aureus, Streptococcus D, Pseudomonas aeruginosa and Acinetobacter baumanii), by using different concentrations. The GC/MS analysis showed that the essential oil is rich in eucalyptol (35.31%), β linalool (22.52%), eugenol methyl ether (9.17%), camphene (7.37%) and 3 carene (5.39%). The antibiotic activity of the essential oil was determined by the diffusion on agar method. Measuring diameters of inhibition method of Vincent [1] indicated that bacterial strains which are very sensitive to even very diluted essential oil are Pseudomonas aeruginosa, Streptococcus D, Serratia sp. and Klebsiella pneumoniae. Staphylococcus aureus, E. coli and Acinetobacter baumanii exhibit less sensitivity and Proteus sp. is especially sensitive to the pure oil. Laurus nobilis L. is a Mediterranean endemic that presents an interesting antibacterial activity and its culture should be encouraged and expanded in Algeria. Key words: Laurus nobilis L., Algerian east, essential oil, GC/MS, antibiotic activity.
Full-text available
The aim of this study was to evaluate the antimicrobial and antioxidant activity of the essential oil (EO) extracted from the leaves of Laurus nobilis L. The oil was analyzed by gas chromatography and mass spectrometry (GC-MS). Twenty seven components were identified, representing 96.6 % of the EO. The main compounds identified were 1,8-cineole (51.8 %), α-terpinyl acetate (11.2 %), and sabinene (10.1 %). The oil was screened for possible antioxidant activity using two complementary test systems: DPPH (2,2- diphenylpicrylhydrazyl) free radical-scavenging and the β-carotene/linoleic acid assay. Both of these in vitro methods showed that the EO was a less powerful reducing agent than the well-known synthetic antioxidants, butylated hydroxytoluene and ascorbic acid. Also, the antimicrobial activity of the EO was tested against a panel of food-spoiling bacteria and one yeast strain. The minimum inhibitory concentration values for microorganisms that were sensitive to L. nobilis EO ranged from 125-2000 µg/mL.
Full-text available
Effects of laurel and myrtle extracts on the sensory, chemical and microbiological properties of vacuum-packed and refrigerated European eel (Anguilla anguilla) fillets Summary The effects of extracted natural antioxidant (laurel and myrtle) on the sensory, chemical (TVB-N, TBARS, PV, FFA and pH) and microbiological (total viable count, psychrotrophic bacteria and Enter-bacteriaceae counts) properties of vacuum-packaged European eel (Anguilla anguilla) stored at 4 AE 1 °C were investigated. The TBARS values of myrtle were significantly lower than that of other groups. The peroxide value was low for European eel treated with myrtle and laurel extract. The FFA-free fatty acid concentration increased from 0.44 (% oleic acid) (2.03) in the eel during 24 days of storage. The values of pH showed statistically significant (P < 0.05) changes for all groups. The myrtle significantly reduced bac-terial growth in fillets (P < 0.05). The microbiological limit of 7 log cfu per gram did not exceed in the treated groups. Data showed that the extracts of myrtle and laurel contain substances that inhibit oxida-tion of lipids and growth of bacteria in European eel, indicating the potential value of these extracts to extend the shelf life of fish.
The present study reports the green synthesis of zinc oxide nanoparticles using the aqueous leaf extract of Laurus nobilis (Ln-ZnO NPs) by co-precipitation method. The synthesized Ln-ZnO NPs were characterized by UV–Vis spectroscopy, FTIR, XRD, TEM, SEM and EDX. Ln-ZnO NPs were crystalline in nature, flower like and have hexagonal wurtzite structure with a mean particle size of 47.27 nm. The antibacterial activity of Ln-ZnO NPs was greater against Gram positive (Staphylococcus aureus) bacteria than Gram negative (Pseudomonas aeruginosa) bacteria. The zone of inhibition against S. aureus was 11.4, 12.6 and 14.2 mm at 25, 50 and 75 μg mL−1. The zone of inhibition against P. aeruginosa was 9.8, 10.2 and 11.3 mm at 25, 50 and 75 μg mL−1. The light and confocal laser scanning microscopic images evidenced that Ln-ZnO NPs effectively inhibited the biofilm growth of S. aureus and P. aeruginosa at 75 μg mL−1. The cytotoxicity studies revealed that Ln-ZnO NPs showed no effect on normal murine RAW264.7 macrophage cells. On the other hand, Ln-ZnO NPs were effective in inhibiting the viability of human A549 lung cancer cells at higher concentrations of 80 μg mL−1. The morphological changes in the Ln-ZnO NPs treated A549 lung cancer cells were observed under phase contrast microscope.