In vitro Antidiabetic Studies of Aqueous Extract of Pleurotus ostreatus Grown on Different Substrates

Abstract

Background and Objective: Nature-derived products are finding increased application for therapeutic purposes. Apart from their use as food, mushrooms have been reported in various research to contain bioactive compounds with medicinal capabilities. This study evaluated the in vitro antidiabetic and antioxidant activities of an aqueous extract of Pleurotus ostreatus (mushroom) cultivated on rice bran/sawdust (RB/SD, 70:30 w/w) mixture and sawdust (SD) substrates. Materials and Methods: Pleurotus ostreatus was cultivated on two different substrates followed by aqueous extraction of mature mushrooms.In vitro antidiabetic, (α-amylase and α-glucosidase inhibition) and antioxidant (DPPH radical-scavenging assay and ferric reducing power (FRAP) activities were done using standard methods. Results were analyzed using IBM Statistical Product and Service Solutions (SPSS) software, version 23 and the significance level was established at p<0.05. Results: The extracts showed a concentration-dependent inhibitory effect on α-amylase and α-glucosidase activities in vitro. There was a stronger inhibition of α-amylase activity by the RB/SD sample when compared to SD and a weaker inhibitory effect of the RB/SD sample on α-glucosidase activity when compared to SD. Again, the samples showed a concentration-dependent antioxidant effect with increased DPPH-scavenging activity and FRAP observed with the SD sample compared to the RB/SD sample. The GC-FID analysis of the P. ostreatus samples also revealed the presence of a number of bioactive compounds in different concentrations. Conclusion: These results highlight the effect of cultivation substrate on the potential therapeutic effect of mushrooms the aqueous extract of P. ostreatus could be a promising raw material for the development of anti-diabetes therapeutics.