Inhibitory effect on alpha glucosidase of herbs and local vegetables in Sakon Nakhon province

Abstract

The objective of this research is to investigate the inhibitory effect of thai traditional herbs on alpha-glucosidase activity. Eight herbs were selected by thai traditional using for anti-diabetic is Syzygium gratum (Wight) S.N.Mitra var. gratum, Cratoxylum formosum (Jack) Benth. & Hook. f. ex Dyer, Careya sphaerica Roxb, Ficus racemosa Linn, Tinospora crispa (L.) Miers ex Hook.f. & Thomson, Morinda citrifolia L., Senna siamea  (Lam.) Irwin & Barneby and Phlogacanthus pulcherrimus T.Anderson. The four extraction method are boiling ,simmer, 50% ethanol and 95%ethanol were used to prepare the plant extracts. The plant extracts that were strongly inhibitory effect were mixed and used to test synergistic effect for inhibition of alpha-glucosidase activity. The colorimetric method was applied to test alpha-glucosidase activity  by measuring absorbance of p-nitrophenol (pNP) that is the product of the reaction between alpha-glucosidase and P-nitrophenyl-α-D-glucopyranoside (pNPG). The plant extracts were different color and quantity. Phlogacanthus pulcherrimus T.Anderson is the highest %yied while Tinospora crispa (L.) Miers ex Hook.f. & Thomson is the smallest %yield. The results showed that three plants are more potent inhibitory effect than acarbose were Syzygium gratum (Wight) S.N.Mitra var. gratum, Careya sphaerica Roxb., Cratoxylum formosum (Jack) Benth. & Hook. f. ex Dyer. Therefore the three plants that have strongly inhibitory effect of alpha-glucosidase activity are suitable for further Development to anti-diabetic herbal drugs.