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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. · 1.85 Impact Factor
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ABSTRACT: The effect of the lyophilized decoction of Salvadora persica on ulceration induced by ethanol, indomethacin and cold restraint stress was investigated in rats. Pre-treatment tests in rats revealed that the extract possessed significant protective action against ulcers induced by ethanol or stress. The protective effect was not altered by indomethacin, administered as a prostaglandin biosynthesis inhibitor. Salvadora persica shows some increase in gastric mucus with a certain diminution in the ulcer index in cold stress-induced ulcers. However, the drug failed to heal ethanol and indomethacin-induced ulcers.
09/2008; 37(5):325-328.
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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. · 3.01 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. · 3.01 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. · 3.01 Impact Factor
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ABSTRACT: There is evidence of hepatotoxic effects caused by Perchloroethylene (PCE), presumably due to reactive metabolic intermediates; lipid peroxidation is under study as a potential mechanism of toxicity. We aimed to verify if PCE levels comparable to those reached in the blood of exposed subjects can cause cell damage and lipid peroxidation. The association of PCE with lipid peroxidation inducing drugs (cyclosporine A, valproic acid and amiodarone) was also tested on rat isolated hepatocytes. AST and LDH release, MTT test and lipid peroxidation assay showed that PCE determines dose-dependent effects on rat isolated hepatocytes. The toxic potential resulting from our data would be valproic acid < cyclosporine A < amiodarone. While valproic acid and cyclosporine caused a mild toxicity, the effects of amiodarone were more severe; in particular, the association of PCE with amiodarone showed a clear additive effect. The role of lipid peroxidation in the liver toxicity exerted by the tested compounds was confirmed by our data, and resulted relevant after treatment of cells with amiodarone and PCE. Extrapolating these results to human, we can suggest that a subject professionally exposed to PCE, who chronically assumes a lipid peroxidation inducing drug like amiodarone, may be potentially exposed to a higher risk of liver toxicity.
Toxicology in Vitro 03/2004; 18(1):37-44. · 2.78 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. · 2.17 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. · 2.65 Impact Factor
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ABSTRACT: The topoisomerase I inhibitors are a new class of antineoplastic agents currently under clinical development. Among these compounds there are some camptothecin (CPT) derivatives with improved toxicity profiles and antitumor activity: irinotecan (CPT-11) and topotecan (TPT), particularly active against colon, lung and ovarian cancer. The aim of this study was to evaluate the cytotoxicity of CPT, CPT-11, its metabolite SN38 and TPT in a primary culture system of rat hepatocytes. Cytotoxicity was evaluated by measuring the leakage of lactate dehydrogenase (LDH) into the medium and by assessing cell viability in terms of tetrazolium salts (MTT) reduction by mitochondrial dehydrogenase activity. Our results showed that cytotoxicity was limited in the case of short drug exposure. There was a significant and time-dependent increase in LDH leakage and a significant time- and dose-dependent decrease in MTT reduction after 3 h of incubation (p<0.01). In the treatments with doses related to peak plasma levels, CPT-11 was less responsible for the observed in vitro hepatotoxicity than its metabolite SN38; TPT had lower LDH leakage compared to SN38 and CPT-11 but showed significant and early (3 h) decrease in MTT reduction: this may mean a different mechanism of cellular damage. These results demonstrate that CPT derivatives are directly toxic to liver cells in a distinct time- and dose-related response.
Journal of chemotherapy (Florence, Italy) 08/2000; 12(4):345-51. · 1.08 Impact Factor
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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. · 1.62 Impact Factor
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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 04/2000; 30(5):379 - 384. · 1.62 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. · 1.62 Impact Factor
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ABSTRACT: We have studied the effect of WIN 55,212-2 (a psychoactive cannabinoid agonist), cannabinol (a nonpsychoactive cannabinoid agonist), SR141716A, a cannabinoid CB1 antagonist, and SR144528, a cannabinoid CB2 antagonist, on gastric emptying in the rat. WIN 55,212-2 (0.1-5 mg/kg, i.p.) and cannabinol (0.1-25 mg/kg, i.p.) dose-dependently delayed gastric emptying while SR141716A (1 mg/kg and 5 mg/kg) and SR144528 (1 mg/kg) were without effect. SR141716A (1 mg/kg), but not SR144528 (1 mg/kg), counteracted the inhibitory effect of the two cannabinoid agonists. These results suggest that cannabinoid agonists delay gastric emptying through activation of cannabinoid CB1 receptors, while the endogenous cannabinoid system does not seem to modulate gastric motility.
Archiv für Experimentelle Pathologie und Pharmakologie 09/1999; 360(2):221-3. · 2.65 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. · 2.17 Impact Factor
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ABSTRACT: The antimicrobial properties of a decoction and methanol extract of 13 plant species used in the traditional medicine of Mali, for fever and respiratory tract diseases, have been tested for in vitro antibacterial activity against clinically isolated bacterial strains: Haemophilus influenzae (6 strains); Staphylococcus aureus (5 strains); Streptococcus pneumoniae (3 strains); Streptococcus pyogenes (8 strains) and Moraxella catarrhalis (5 strains) responsible for respiratory infections.The results obtained showed that the extracts from Anogeissus leiocarpus, Guiera senegalensis (Combretaceae) and Diospyros mespiliformis (Ebenaceae), have a significant activity against all strains of bacteria tested. Crossopteryx febrifuga and Pteolopsis suberosa showed moderate activity only against S. aureus. © 1998 John Wiley & Sons, Ltd.
Phytotherapy Research 12/1998; 12(S1):S154 - S156. · 2.09 Impact Factor
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ABSTRACT: The leaf decoction of Guiera senegalensis possesses an antitussive activity. The antitussive activity of Guiera was evaluated using the classical citric acid-evoked cough model in guinea-pigs. The leaf decoction of the leaves of Guiera dose-dependently decreased the number of coughs. The cytotoxicity test showed that the acute cytotoxic concentration of Guiera decoction was >1000 μg/mL. © 1998 John Wiley & Sons, Ltd.
Phytotherapy Research 12/1998; 12(2):132 - 134. · 2.09 Impact Factor
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ABSTRACT: Pteleopsis suberosa Engl. et Diels was used in the traditional medicine of Mali for the treatment of gastric and duodenal ulcers. In an ethnopharmacological approach, Pteleopsis suberosa extracts of the stem bark were investigated for antiulcer and antibacterial activity against Helicobacter pylori standard strains and clinical isolates. The decoction, the traditional form of administration of the drug in Mali, and the methanolic extract were active against all the bacterial strains tested. The minimum inhibitory concentrations ranged from 62.5 to 500 microg/ml for the decoction and from 31.25 to 250 microg/ml for the methanolic extract. The results indicate that Pteleopsis suberosa may be a source of compounds with a therapeutic potential against gastric ulcers associated with Helicobacter pylori infections.
Journal of Ethnopharmacology 01/1998; 59(3):167-72. · 3.01 Impact Factor
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R Ficarra,
P Ficarra,
S Tommasini,
M Carulli,
S Melardi,
M R Di Bella,
M L Calabrò,
R De Pasquale, M P Germanò,
R Sanogo,
F Casuscelli
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ABSTRACT: A combination of thin-layer chromatography, high-performance liquid chromatography, UV spectroscopy and NMR spectrometry techniques for analysis of flavonoid content of Guiera senegalensis J.F.Gmel. (Combretaceae) leaves is described. Four components, catechin, myricitrin, rutin and quercetin were evidenced and determined by HPLC.
Bollettino chimico farmaceutico 06/1997; 136(5):454-9.
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ABSTRACT: Different extracts of Mitracarpus scaber aerial parts were investigated for in vitro antibacterical and antimycotic activities against strains of laboratory microorganisms and clinical isolates responsible for skin infections. The diethyl ether extract possesses a rather good activity: the minimum inhibitory concentration ranged from 15.6-31.25 μg/ml against standard strains of Candida sp. and from 7.8-125 μg/ml against clinical isolates strains. Staphylococci were inhibited at 3.9-62.5 μg/ml (standard strains) and at 1.9-15.6 μg/ml (clinical isolates). The results confirm the rationale of the folkloric use of Mitracarpus in treating fungal and bacterial infections.
Phytomedicine 01/1996; 2(3):265-8. · 3.27 Impact Factor
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ABSTRACT: The effects of high levels of cadmium in soil and in the atmosphere on the plants of Coriandrum sativum L. (Umbellifereae) were investigated. Plants grown in contaminated soil (0, 10, 100 ppm of cadmium) showed a significant reduction in the length of the stems and roots and the number of the umbels, a yellowing and ultrastructural alterations of the leaves and a significant decrease in the essential oil composition. Similar effects were observed in the plants exposed to a simulated atmospheric pollution (plants were sprayed with CdCl2 solutions containing Cd 0, 10, 100 mg/L). The effects are related to a degree of environmental contamination.
Water Air and Soil Pollution 08/1995; 84(1):147-157. · 1.63 Impact Factor
