BIOPROSPECTING OF THE ENDOPHYTIC FUNGI FROM STEVIA REBAUDIANA FOR THE PRODUCTION OF STEVIOSIDE AND REBAUDIOSIDE A: SCREENING AND CHROMATOGRAPHIC CHARACTERIZATION

Abstract

Bioactive secondary metabolites produced from the endophytic fungi offering a significant potential in pharmaceutical sectors. Steviol glycosides are the diterpenoids secondary metabolites which are found inside the plant Stevia rebaudiana Bertoni. This study represents a systematic and structural framework for the extraction, preliminary screening and chromatographic analysis of the bioactive SMs derived from the endophytic fungal isolates. Total 108 endophytic fungal isolates obtained from plant S.rebaudiana in which 48 isolates were morphologically different subjected to the Richard’s culture broth fermentation for synthesizing the steviol glycosides followed by thoroughly extraction of secondary metabolites by ethyl acetate in 1:1. The resulting crude extracts were initially screened by anthrone and salkwoski test to identify fungal isolates capable of producing carbohydrate and terpenoid associated secondary metabolites. Selected two positive samples were further analyzed on TLC Silica gel 60 F254 plate by using solvent phase ethyl acetate, methanol, formic acid (93:40:1 v/v/v). High performance liquid chromatography showed two different Rt value for both stevioside and rebausdioside A in solvent ACN and water (80:20) by using column 2.50 mm × 4.6 mm. The current findings demonstrate that endophytic fungi resides inside the plant S.rebaudiana is a promising microbial resource for identifying alternative routes for the production of stevioside and rebaudioside