Isolation characterization and process optimization of resveratrol production from endophytic fungi

Abstract

The present study focusses on the diversity of resveratrol producing fungal endophytes associated with different wine grape varieties grown in India. A total of 145 endophytic isolates were recovered of which 55 were from Pune region, 54 from Nashik while 26 were from Lucknow and 9 from Bengaluru. Only 30% isolates exhibited extracellular resveratrol production in the preliminary screening. However only 14 fungal endophytes exhibited significant resveratrol production in the range of 4.4g/L-89.1g/L in liquid cultures which was evaluated by HPLC analysis. Four potent resveratrol producing endophytes isolated were #12VVLPM; #4(P)VVLNM; #22(P) VVLPM and #19VVLPM. #12 VVLPM was identified to be Arcopilus aureus, while #22(P) VVLPM was identified to be Xylaria psidii. Both Arcopilus aureus and Xylaria psidii have so far not been reported to be resveratrol producers. The other two isolates viz. #4(P)VVLNM and #19VVLPM are generalists identified as Fusarium solani and Fusarium equiseti. Highest resveratrol production, 89.1 g/l was recorded in #12VVLPM identified as Arcopilus aureus. The fungal resveratrol exhibited a strong anti-oxidant activity in all the tested assays.The endophytic isolate #12VVLPM exhibited the best activity similar to the standards in the entire anti-oxidant assay performed during the present course of investigations. Yet another important result was the antimycotic activity against different plant as well as human pathogenic fungi tested. The highest inhibition was observed against B. cinerea (57.8± 0.8%) followed by Cercospora beticola (ATCC24888) by extracts of #12VVLPM while the least inhibition was observed in #22(P) VVLPM and #4(P) VVLNM against same pathogen. Among the resveratrol producing endophytic isolates #12VVLPM exhibited the best inhibitory activity against all the cultures tested in the panel. The fungal resveratrol was obtained in pure form ethnolic extract by eluting it in a column with mobile phase of MeOH: DCM :: 1.75:98.25.