Alpha·Glucosidase Inhibitor Activity And Characterization Of Endophytic Actinomycetes Isolated From Some Indonesian Diabetic Medicinal Plants

Abstract

An alpha glucosidase inhibitor is one of the compounds for the treatment or diabetes. This inhibitor can retard the liberation of glucose from dietary complex carbohydrates and delay glucose absorption. resulting in reduced postprandial plasma glucose levels and suppress postprandial hyperglycaemia. The purpose of this study was to isolate and select alpha glucosidase inhibitor-producing endophytic actinomycetes from various diabetic medicinal plants. Endophytlc actinomycetes were isolated from the roots, leaves and stems of diabetic medicinal plants: A//oe vera, Tinosporo crispa, Phalerio mocrocorpa. Curcumo oeru9inoso, Centela aslatica, Xoncus orvensis, Andro9rophis ponicu/ata, Caesa/plnia sappan, Curcumo xanthoriza, Parcia speciosa. Gynura procumbens, Physolis peruviana and Hibiscus sabdariffa. Sterilized plant sample were inoculated on the HV Agar medium containing 50 ppm cycloheximide and 30 ppm nalid1x1c acid and were incubated for 2-3 weeks at room temperature. Sixty-five isolates were obtained and tested for their ability to inhibit the alpha·glucosidase. Identification for the selected isolates was based on 16S rDNA sequences. The inhibitor activity to alpha glucosidase was determined spectrophotometrically at 400 nm usmg p·N1trophenyl-alpha-D-glucopyranoside as a substrate, and acarbose as a positive c;ontroL The results showed that endophytic actinomycetes isolated from selected antidiabetic plants produced various inhibition activities. The highest inhibition activity to alpha·glucosidase was shown by BWA65 found from Tmospora cnspa. Production of alpha·glucosidase inhibitor compounds in this plant largely related with the contribution of its actinomycetes endophytes. The molecular Identification based on 16S rONA sequence revealed that the potential BWA65 isolate showed 92% similarity to Streptomyces olivochromogenes.