V D'Angelo

Julphar School of Pharmacy, Italy, Texas, United States

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Publications (14)29.47 Total impact

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    ABSTRACT: In this study, a methanolic extract of Betula pendula leaves (BLE) was investigated for its gastroprotective effects against 90% ethanol-induced ulcer in rats. Oral pretreatment of rats with BLE (100, 200 and 400 mg kg(- 1)) significantly reduced the incidence of gastric lesions induced by ethanol administration as compared with misoprostol (0.50 mg kg(- 1)). Furthermore, BLE inhibited the increase in malondialdehyde (MDA) and prevented depletion of total sulhydryl and non-protein sulhydryl groups in rat stomach homogenate when compared with ethanol group. With regard to the effect of lipid peroxidation in vitro, BLE showed the ability to reduce methyl linoleate autoxidation. Chemical characterisation of the main biologically active constituents of BLE was also achieved by means of high-performance liquid chromatography with photodiode array and mass spectrometry detection, showing the presence of myricetin-3-O-galactoside, quercetin glycosides, kaempferol glycosides.
    Natural product research 11/2012; · 1.01 Impact Factor
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    ABSTRACT: The research of new tyrosinase inhibitors is currently important for the development of skin whitening agents; particularly, birch leaves extracts are included in many skin cosmetic products. In this study, the potential ability of Betula pendula leaves ethanolic extract (BE) was evaluated on mushroom tyrosinase activity. Results showed that BE was capable to inhibit dose-dependently l-DOPA oxidation catalyzed by tyrosinase. The inhibition kinetics, analyzed by Lineweaver-Burk plots, showed a noncompetitive inhibition of BE towards the enzyme, using l-DOPA as substrate. The inhibitory mechanism of BE as studied by spectrophotometric analysis, demonstrated its ability to chelate copper ion in the active site of tyrosinase. In addition, BE exhibited Fe(2+)-chelating ability (IC(50)=614.12±2.14 μg/mL), reducing power and radical-scavenging properties (IC(50)=137.22±1.98 μg/mL). These results suggest the usefulness of birch leaves extracts in cosmetic and pharmaceutical industries for their skin-whitening and antioxidant effects. Determination of the polyphenolic compounds in BE extracts was afterward achieved by means of high-performance liquid chromatography (HPLC) with photodiode array (PDA) and mass spectrometry (MS) detection. A total of 25 compounds were positively identified, through the complementary analytical information, and are reported in such a matrix for the first time. Knowledge on the qualitative composition and contents of these natural sources in fact represents mandatory information, for rational consumption and correlation of the beneficial effects to the specific amounts.
    Fitoterapia 03/2012; 83(5):877-82. · 2.23 Impact Factor
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    ABSTRACT: Pteleopsis suberosa Engl. et Diels (Combretaceae) is a tree distributed in many African countries. The decoction from the stem bark is orally administered for the treatment of gastric ulcers in traditional medicine. Previous pharmacological studies reported the anti-ulcer activity of extracts from P. suberosa stem bark. In the present study, the anti-ulcer and anti-inflammatory effects of the n-butanol fraction (RBuOH) obtained from a methanol extract of P. suberosa bark were investigated on ethanol-induced gastric ulcers in rats and carrageenan-induced paw oedema in mice. Misoprostol (0.50 mg/kg, p.o.) and indomethacin (8.00 mg/kg, p.o.) were used as positive controls for anti-ulcer and anti-inflammatory activities, respectively. Results showed that RBuOH treatment significantly reduced the incidence of gastric lesions (50 mg/kg, P<0.05; 100 and 200 mg/kg, P<0.01) and restored the decreased levels of total sulfhydryl groups (T-SH) and non-protein sulfhydryl groups (NP-SH) (50, 100 mg/kg, P<0.05; 200 mg/kg, P<0.01) in the stomach homogenate. Moreover, RBuOH treatment attenuated MDA levels as index of lipid peroxidation in gastric mucosa. Administration of RBuOH at the same dosage (50, 100 and 200 mg/kg) reduced significantly (P<0.01) carrageenan-induced paw oedema in dose-dependent manner (from 42.81% to 87.81% inhibition, 5h after carrageenan injection). The anti-inflammatory effect of RBuOH at 200 mg/kg was comparable with that of indomethacin. Finally, RBuOH proved to possess elevated free radical scavenger capacity on 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay (IC(50) 23.48 microg/ml) which may contribute to the observed anti-ulcer and anti-inflammatory activities.
    Journal of Ethnopharmacology 01/2008; 115(2):271-5. · 2.76 Impact Factor
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    ABSTRACT: Thirteen oleanane saponins (1-13), four of which were new compounds (1-4), were isolated from Pteleopsis suberosa Engl. et Diels stem bark (Combretaceae). Their structures were determined by 1D and 2D NMR spectroscopy and ESI-MS spectrometry. The compounds were identified as 2alpha,3beta,19alpha,23,24-pentahydroxy-11-oxo-olean-12-en-28-oic acid 28-O-beta-D-glucopyranosyl ester (1), 2alpha,3beta,19beta,23,24-pentahydroxy-11-oxo-olean-12-en-28-oic acid 28-O-beta-D-glucopyranosyl ester (2), 2alpha,3beta,19alpha,23-tetrahydroxy-11-oxo-olean-12-en-28-oic acid 28-O-beta-D-glucopyranosyl ester (3), and 2alpha,3beta,6beta,19alpha,24-pentahydroxy-11-oxo-olean-12- en-28-oic acid 28-O-beta-D-glucopyranosyl ester (4). The presence of alpha,beta-unsaturated carbonyl function was not common in the oleanane class and the aglycons of these compounds were not found previously in the literature. Moreover, the isolated compounds were tested against Helicobacter pylori standard and vacA, and cagA clinical virulence genotypes. Results showed that compound 6 has an anti-H. pylori activity against three metronidazole-resistant strains (Ci 1 cagA, Ci 2 vacA, and Ci 3).
    Phytochemistry 04/2007; 67(24):2623-9. · 3.35 Impact Factor
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    ABSTRACT: Trichilia emetica Vahl. is commonly used in folk medicine of Mali for the treatment of various diseases. In this study, the content and the antioxidant activity of phenolic acids from Trichilia emetica root were evaluated. Free phenolic acids were extracted with a mixture of methanol and 10% acetic acid. Bound phenolic acids were released using first alkaline and then acid hydrolysis. All fractions were quantified separately by HPLC. After alkaline hydrolysis, a remarkable increase in caffeic acid, ferulic acid, p-coumaric acid, syringic acid, vanillic acid, protocathecuic acid and gallic acid content was observed, showing that most of phenolic acids in the drug are present as bound forms. Moreover, the extracts submitted to alkaline hydrolysis showed high antioxidant properties in two in vitro assays: autooxidation of methyl linoleate (MeLo) and ascorbate/Fe(2+)-mediated lipid peroxidation in rat microsomes. An in vivo study was also performed to investigate the intestinal absorption of phenolic acids after oral administration of Trichilia emetica extracts. Results showed high levels of phenolic acids, free or conjugated to glucuronide, in the plasma of rats treated with the hydrolyzed extract. Due to the absence of chlorogenic acid in plasma samples, the presence of caffeic acid seems to be derived from hydrolysis of chlorogenic acid in the gastrointestinal tract.
    Journal of Ethnopharmacology 06/2006; 105(3):368-73. · 2.76 Impact Factor
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    ABSTRACT: Trichilia emetica Vahl. (Meliaceae) is a tree widely distributed in Tropical Africa. It has been used in Mali folk medicine for the treatment of various illnesses. The aim of this work was to study the hepatoprotective and antibacterial effects of a crude aqueous extract from Trichilia emetica root. An ethyl ether fraction from the aqueous extract was also prepared and studied. We have examined the hepatoprotective activity of the extracts on CCl4-induced damage in rat hepatocytes, their toxicity using the brine shrimp bioassay and their antibacterial activity against clinical isolated bacterial strains, which are commonly responsible for respiratory infections. A preliminary phytochemical analysis showed a high polyphenolic content in the aqueous extract and the presence of limonoids in the ethyl ether fraction. These latter compounds may be considered responsible for the good activity against the bacterial strains tested. Trichilia emetica extracts exerted also a significant (P<0.05) hepatoprotective effect at a dose of 1000 microg/ml both on plasma membrane and mitochondrial function as compared to silymarin used as a positive control. These activities may be a result of the presence of either polyphenols or limonoids. Finally, both the aqueous extract and its ethyl ether fraction did not show toxicity (LC50>1000 microg/ml) in the brine shrimp bioassay.
    Journal of Ethnopharmacology 01/2005; 96(1-2):227-32. · 2.76 Impact Factor
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    ABSTRACT: The antioxidant activity of extracts from Capparis spinosa L. buds was evaluated using different in vitro tests: ascorbate/Fe(2+)-mediated lipid peroxidation of microsomes from rat liver; bleaching of 1,1-diphenyl-2-picryl-hydrazyl radical; and autoxidation of Fe(2+) ion in the presence of bathophenanthroline disulfonate. The methanolic extract showed strong activities in all of these in vitro tests. The amount of total phenols was determined in the methanolic extract. In addition, the level of rutin was calculated as 0.39% (w/w) by HPLC analysis. Our findings indicate the following: (a) the antioxidant efficiency of the methanolic extract may be attributed to its phenolic content; and (b) the antioxidant activity of the methanolic extract was maintained after removal of glucosinolates, confirming that these compounds do not interfere with the antioxidant properties of the extract. The results obtained from this study exalt the nutritional value of the flowering buds (capers) which are widely used as a source of flavor.
    Journal of Agricultural and Food Chemistry 03/2002; 50(5):1168-71. · 3.11 Impact Factor
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    ABSTRACT: Trichilia roka Chiov. (Meliaceae) is a tree widely distributed in tropical Africa. It has been used in Mali folk medicine for the treatment of various illnesses. A decoction of the roots is taken as a remedy for colds and pneumonia, and it is used as a diuretic and in hepatic disorders. We have evaluated the hepatoprotective effects of a decoction of Trichilia roka root on CCl4-induced acute liver damage in rats. Treatment with the decoction showed a significant protective action made evident by its effect on the levels of glutamate oxalacetate transaminase and glutamate pyruvate transaminase in the serum, on the protein content and lipid peroxidation levels in the liver homogenate. Histopathological changes produced by CCl4, such as necrosis, fatty change, ballooning degeneration and inflammatory infiltration of lymphocytes around the central veins, were clearly recovered by the treatment with Trichilia root decoction. On fractionating this extract into diethyl ether-soluble and water-soluble fractions, the activity was retained in the diethyl ether-soluble fraction. Moreover, the administration of decoction prevented a preferential deposition of collagen around the sinusoidal cell layer, which is responsible for the perisinusoidal fibrosis in the early stage of CCl4 damage. This study showed that treatment with Trichilia roka extracts or silymarin (as reference) appeared to enhance the recovery from CCl4-induced hepatotoxicity. The hepatoprotective properties of Trichilia roka may be correlated to polyphenol content of the decoction and its diethyl ether-soluble fraction.
    Journal of Pharmacy and Pharmacology 12/2001; 53(11):1569-74. · 2.03 Impact Factor
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    ABSTRACT: The effect of cannabinoid drugs (i.p.) on cold/restraint stress-induced gastric ulcers was studied in rats. The cannabinoid receptor agonist (WIN 55,212-2, 0.1-1 mg/kg), but not the less active isomer WIN 55,212-3 (1 mg/kg), reduced gastric ulceration. The protective effect of WIN 55,212-2 (1 mg/kg) was counteracted by the cannabinoid CB1 receptor antagonist SR141716A, but not by the cannabinoid CB2 receptor antagonist SR144528. These results indicate that the antiulcer effect of the cannabinoid receptor agonist WIN 55,212-2 is mediated by cannabinoid CB1 receptors.
    Archiv für Experimentelle Pathologie und Pharmakologie 03/2001; 363(2):241-4. · 2.15 Impact Factor
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    ABSTRACT: The dried aqueous extract of Trichilia roka Chiov. (Meliaceae) root was evaluated for its potential antipyretic activity on yeast-induced hyperthermia in rats. The drug showed a significant reduction of body temperature when administered orally at the doses of 0.25, 0.5 and 1.0 g/kg. The antipyretic activity of T. roka was compared to indomethacin treatment (50 mg/kg), used as a reference drug. The results of this study confirm the validity of traditional usage of T. roka as an antipyretic agent. Moreover, micromorphological investigations were carried out by scanning electron microscopy obtaining useful phytognostic elements for the correct identification of the drugs both in scraped and powdered forms because this is of great interest for quality control in basic research and drug production, especially for imported items and for raw material sold by traditional herborists.
    Il Farmaco 01/2001; 56(5-7):357-60.
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    ABSTRACT: A comparative study on the antimicrobial properties of extracts from medicinal plants obtained by two different methods was carried out. The screening of the antimicrobial activity of extracts from six plants was conducted by a disc diffusion test against Gram-positive, -negative and fungal organisms. The most active extracts (inhibition diameter >/=12 mm) were assayed for the minimum inhibitory concentration and submitted to phytochemical screening by thin-layer chromatography and bioautography. The results obtained indicate that the diethyl ether extracts were the most efficient antimicrobial compounds. The activity was more pronounced against Gram-positive and fungal organisms than against Gram-negative bacteria. Bioautography showed that the antimicrobial activity was probably due to flavonoids and terpenes.
    Letters in Applied Microbiology 05/2000; 30(5):379-84. · 1.63 Impact Factor
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    ABSTRACT: The antimicrobial activity of a methanol extract and isolated constituents of Mitracarpus scaber, a species used in folk medicine by West African native people, was evaluated against Staphylococcus aureus and Candida albicans strains. The mitracarpus methanol extract possesses both antibacterial and antimycotic activities (minimum inhibitory concentration-MIC 31.25 and 62.50 microg ml-, respectively). This extract was subsequently fractioned and monitored by bioassays leading to the isolation of seven compounds screened for antibacterial and antimycotic activities. Among these compounds, gallic acid and 3,4,5-trimethoxybenzoic acid inhibited the growth of Staph. aureus (MIC 3.90 and 0.97 microg ml-). 4-Methoxyacetophenone and 3,4,5-trimethoxyacetophenone effectively inhibited C. albicans (MIC 1.95 microg ml-). The other compounds (kaempferol-3-O-rutinoside, rutin and psoralen) which were also isolated showed low antibacterial and antimycotic activities (125-500 microg ml-).
    Letters in Applied Microbiology 03/2000; 30(2):105-8. · 1.63 Impact Factor
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    ABSTRACT: Crossopteryx febrifuga, Pteleopsis suberosa and Entada africana are used in Mali traditional medicine for fever and various respiratory diseases. We have investigated the effects of these three drugs in the form of a decoction on the respiratory tract using different experimental models. On citric acid-induced cough in guinea-pigs, the three drugs significantly decreased the number of coughs at the doses of 250 (P < 0.01), 500 (P < 0.05; P < 0.01) and 1000 (P < 0.01) mg kg(-1). The percent inhibition was respectively 62.86, 69.03 and 77.44% for C. febrifuga, 57.80, 53.90 and 61.40% for E. africana, and 37.13, 42.44 and 73.72% for P. suberosa. Codeine phosphate (10 mg kg(-1)) used as reference drug showed an inhibition of 76.32%. E. africana (1000 mg kg(-1)) reduced (65% inhibition) significantly (P < 0.05) bronchoconstriction induced by histamine (99.25% and 34.00% for control and extract, respectively). Furthermore, E. africana (1000 mg kg(-1)) provoked a bronchodilatation response when administered under basal conditions. On antigen-induced bronchospasm, C. febrifuga protected (54% inhibition) sensitized guinea-pigs with a pulmonary ventilation pressure (PVP) of 24.87% (control value < 55.00%). P. suberosa was inactive in both experimental models. The reference drug, disodium cromoglycate (10 mg kg(-1), i.v.) protected significantly (P < 0.05) with a PVP of 12.00% (78% of inhibition). This study confirmed the traditional use of these plants in the treatment of cough and other respiratory disorders.
    Journal of Pharmacy and Pharmacology 12/1999; 51(11):1299-303. · 2.03 Impact Factor
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    ABSTRACT: The effect of Mitracarpus scaber on carbon tetrachloride-induced acute liver damage in the rat has been evaluated. Results showed that treatment with Mitracarpus scaber decoction resulted in significant hepatoprotection against CCl4-induced liver injury both in-vivo and in-vitro. In-vivo, Mitracarpus scaber pretreatment reduced levels of serum glutamate-oxalate-transaminase (P < 0.01 for 250, 500 and 1000 mg kg(-1)) and serum glutamate-pyruvate-transaminase (P < 0.05 for 250 mg kg(-1) and P < 0.01 for 1000 mg kg(-1)) previously increased by administration of CCl4. In-vitro results indicated that addition to the culture medium of Mitracarpus scaber extracts significantly reduced glutamate-oxalate-transaminase (P < 0.05 for 100 microg mL(-1) and P < 0.01 for 10 and 1000 microg mL(-1)) and lactate dehydrogenase activity (P < 0.05 for 10 microg mL(-1)). Mitracarpus treatment also resulted in a good ( > 93%) survival rate for the CCl4-intoxicated hepatocytes as demonstrated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. Moreover, as in the in-vitro assay, Mitracarpus scaber had radical-scavenging properties, shown by its reaction with the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical (EC50, the extract concentration resulting in a 50% reduction in the absorbance of DPPH blank solution, = 41.64+/-1.5 microg mL(-1)). The results of this study showed that Mitracarpus scaber had antihepatotoxic potential, a finding which supports the validity of traditional usage of this drug in Mali for the treatment of liver diseases.
    Journal of Pharmacy and Pharmacology 07/1999; 51(6):729-34. · 2.03 Impact Factor