In-vitro studies on α-amylase, α-glucosidase and aldose reductase inhibitors found in endophytic fungi isolated from Ocimum sanctum

摘要

Eighty four endophytic fungi were isolated from Ocimum sanctum. Secondary metabolites extracted from these endophytic fungi were tested for the inhibitors of enzymes responsible for the glycaemic index and polyol pathway. Six isolates were positive for both α-glucosidase and α-amylase inhibitors. Secondary metabolites from four endophytic fungal isolates inhibited aldose reductase enzyme extracted from rat lens. Crude extracts of fungal isolates POST075 and POST083 were found to be the most potent α-glucosidase inhibitors among the active isolates with IC50 values of 29.51 and 31.26 μg/mL respectively. Whereas, ethyl acetate extracts of fungal isolates POST034 and POST075 showed highest inhibition for pancreatic α-amylase enzyme in-vtiro with an IC50 value of 27.34 and 40.73 μg/mL respectively. The IC50 value for α-amylase enzyme inhibitors of POST034 and POST075 was very close to IC50 value of standard drug acarbose (25.7 μg/mL) tested under similar conditions. Crude extract of endophytic fungal isolate POST047 was found to be an effective aldose reductase inhibitor with an IC50 value of 29 μg/mL when compared to the IC50 value of standard drug quercetin that has an IC50 value of 15 μg/mL under similar condition. Fungal isolates with best inhibition activity were identified as Alternaria tenuissima (POST34), Trichoderma sp. (POST047), Diaporthe sp (POST075) and Colletotrichum gloesporioides (POST083) by the rDNA molecular method.