Phenolic content and in vitro inhibitory effects on oxidation and protein glycation of some Thai medicinal plants.

Department of Pharmaceutical Sciences, Chiang Mai University, Chiang Mai 50200, Thailand.
Pakistan journal of pharmaceutical sciences (Impact Factor: 0.95). 10/2010; 23(4):403-8.
Source: PubMed

ABSTRACT Fifteen medicinal plant extracts were investigated for: total phenolic content and free radical scavenging effect by DPPH and ABTS assays; anti-lipid peroxidation activity by TBARS; and for antiglycation activity. The results revealed that the total phenolic content showed good correlation with free radical scavenging by ABTS (r = 0.721) and anti-lipid peroxidation by TBARS (r = -0.659), but showed no correlation with antiglycation. Three extracts from Tamarindus indica, Camellia sinensis and Artocarpus lakoocha demonstrated a significant antioxidant effect, and also showed a promising antiglycation effect. The IC50 (mg/ml) were 0.9-0.16 for the DPPH method; TEAC values (mg Trolox/mg sample) of 1.72-2.83 for the ABTS method; IC50 (mg/ml) of 0.64-1.22 for the TBARS method; and IC50 ranging from 0.01 to 3.20 for the antiglycation method. These three herbs were found to possess effective antioxidant and antiglycation activities, and could be further developed for use in anti-aging cosmetics.

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    ABSTRACT: Garcinia atroviridis is a seasonal fruit plant found in many parts of South East Asia. The fruit rind is used in cooking and traditionally consumed for various reasons including to lower blood cholesterol. A comparative study was undertaken to investigate the influence of extraction solvents and plant parts used on the lipid lowering and antioxidant activities of Garcinia atroviridis. Aqueous extracts showed better antihyperlipidemic activity than the methanol extracts. Aqueous extract of ripe fruit showed the most potent antihyperlipidemic activity, comparable to that of atorvastatin. It significantly reduced the total cholesterol (p<0.05), triglycerides (p<0.01), low density lipoprotein (p<0.01), very low density lipoprotein (p<0.01) and atherogenic index (p<0.01). In contrast, antioxidant activities of methanol extracts of all parts of G. atroviridis were higher than their respective aqueous extracts, whereby the stem and leaves showed extracts better antioxidant activities than the fruits. Aqueous and methanol extracts of G. atroviridis showed higher antihyperlipidemic and antioxidant effects, respectively. Total phenolic and flavonoid contents showed significant correlations with antioxidant but not with antihyperlipidemic activities, indicating the involvement of other compounds. In contrary to the traditional belief, the present findings suggest that the fruit has higher antihyperlipidemic potential than the fruit rind.
    Journal of the Science of Food and Agriculture 10/2013; · 1.76 Impact Factor
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    ABSTRACT: BACKGROUND: Advanced glycation end-products (AGEs) are the final products derived from the non-enzymatic glycation process. AGEs are involved in the development of several health complications associated with diabetes and aging. Searching for anti- AGE extracts is necessary to mitigate the effects of age-related pathologies. RESULTS: The antioxidant and antiglycative activities of eight aqueous extracts of fruit and vegetable seeds were evaluated. All seed extracts (3.6 mg mL(-1) ) exhibited anti-AGE activity in protein-glucose assay, ranging from 20 to 92% inhibition compared with aminoguanidine (4.87 mmol L(-1) ). Green pepper extract exerted the highest anti-AGE activity. However, peach and pomegranate extracts exhibited the highest anti-AGE activity in protein-methylglyoxal assay, ranging from 0 to 79% inhibition. Hazelnut, almond and sesame extracts were not effective when methylglyoxal was the promoter. Apricot and peach extracts appeared to inhibit the formation of AGEs through their capacity for direct trapping of 1,2-dicarbonyls (IC(50) =0.14 mg mL(-1) ). No relationship between antioxidant and phenolic compound content and antiglycative activity was found. Therefore other hydrophilic constituents in addition to phenolic acids must be involved in the antiglycative activity of the extracts. CONCLUSION: Aqueous extracts of fruits and vegetables can be considered in the prevention of glycation-associated complications of age-related pathologies. © 2012 Society of Chemical Industry.
    Journal of the Science of Food and Agriculture 11/2012; · 1.76 Impact Factor
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    ABSTRACT: BACKGROUND: Extracts from Polygonum senegalensis (Polygonaceae) and Pseudocedrela kotschyi (Meliaceae) are two important traditionally used medicinal plants in rural Benin to treat many diseases and notably type 2 diabetes. The aim of the study was to investigate the alpha-glucosidase inhibition, antioxidant and antibacterial activities of those plants extract: Polygonum senegalensis leaves, and Pseudocedrela kotschyi root. METHODS: Hydro-alcoholic (50%) extracts were analyzed for their phytochemical content and tested for their inhibition potency on alpha-glucosidase from Saccharomyces cerevisiae. Antioxidant activities were assessed using the DPPH, ORAC, FRAP and DCFH-DA (cell based) assay. Finally, the antibacterial activity was evaluated using MIC determination on four Gram-positive cocci (Bacillus subtilis, Clostridium difficile, Enterococcus faecalis, Staphylococcus aureus), three Gram-negative bacilli (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae), and the yeast Candida albicans. RESULTS: Each extract presented significant alpha-glucosidase inhibition and antioxidant activities. Polygonum senegalensis leaf extracts were the most active in each in vitro assay with an IC50 = 1.5 mug/ml for alpha-glucosidase inhibition and an IC50 = 6.8 mug/ml for DPPH scavenging, - 4.5 mumol Fe II/g of dry matter - 9366 mumol Trolox / g DW - for FRAP and ORAC values, respectively. IC50 = 2.3 mug GA / ml for DCFH-DA assay. Concerning its antibacterial activity, a growth inhibitory effect was observed only against three Gram negative bacilli: B. subtilis, E. faecalis, S. aureus and the yeast C. albicans at high concentration. CONCLUSION: The results showed that the semi alcoholic extract of the two studied plants possess alpha-glucosidase inhibitory activity, antioxidant potency, and low antibacterial effect.
    BMC Complementary and Alternative Medicine 03/2013; 13(1):51. · 2.08 Impact Factor

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