In vitro biological effects of two anti-diabetic medicinal plants used in Benin as folk medicine
1 Clermont University, Université d’Auvergne, IMTV, F-63000, Clermont-Ferrand, France
2 INSERM, UMR 990, IMTV, F-63005, Clermont-Ferrand, France
3 University of Abomey Calavi, Laboratoire d’étude et de Recherche en chimie Appliquée, Ecole Polytechnique d’Abomey Calavi, Cotonou, Benin
4 Clermont University, Université d’Auvergne, Laboratoire Microorganismes: Génome et Environnement (LMGE), BP 10448, F-63000, Clermont-Ferrand, France
5 CNRS, UMR 6023, LMGE, F-63177, Aubiere, France
BMC Complementary and Alternative Medicine 2013, 13:51 doi:10.1186/1472-6882-13-51Published: 1 March 2013
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 α-glucosidase inhibition, antioxidant and antibacterial activities of those plants extract: Polygonum senegalensis leaves, and Pseudocedrela kotschyi root.
Hydro-alcoholic (50%) extracts were analyzed for their phytochemical content and tested for their inhibition potency on α-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.
Each extract presented significant α-glucosidase inhibition and antioxidant activities. Polygonum senegalensis leaf extracts were the most active in each in vitro assay with an IC50 = 1.5 μg/ml for α-glucosidase inhibition and an IC50 = 6.8 μg/ml for DPPH scavenging, - 4.5 μmol Fe II/g of dry matter - 9366 μmol Trolox / g DW - for FRAP and ORAC values, respectively. IC50 = 2.3 μg 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.
The results showed that the semi alcoholic extract of the two studied plants possess α-glucosidase inhibitory activity, antioxidant potency, and low antibacterial effect.