ISOLATION AND CHARACTERIZATION OF t-RESVERATROL AND α-VINIFERIN, A BIOACTIVE SECONDARY METABOLITE OF AN ENDOPHYTIC FUNGUS ASPERGILLUS STELLIFER AB4, FROM VITIS VINIFERA

Abstract

The secondary metabolite t-resveratrol and α-viniferin is widely recognized bioactive molecules that is known for preventing and slowing the occurrence of many diseases, have attracted great research interest. The aim of this work is to isolate the endophytic microorganisms that possess t-resveratrol and α-viniferin producing capability from the plants of Vitaceae family: Vitis vinifera , Vitis quinquangularis Rend and Cayratia trifolia. Twenty isolates were obtained from the different tissues of all the three plants and all were able to produced t-resveratrol and α-viniferin in different concentrations in their consecutives second subcultures. Aspergillus stellifer AB4 isolated from leaf of Vitis vinifera had shown stable production capability of t-resveratrol 288 μg/L and α-viniferin 301 μg/L in liquid culture, while 19 isolates producing capability diminished after third subculture. Optimization of the conditions for t-resveratrol and α-viniferin production by A. stellifer AB4 were studied, an inoculum size of 10% v/v (2x104) spore number/ml, a rotation speed of 100 rpm, and a temperature of 28°C and pH 7 was optimum for the production of t-resveratrol and α-viniferin. Growth of A. stellifer AB4 increased during cultivation, reached high level of biomass 1.98± 1.7 on 7th day and the highest production of t-resveratrol 300 μg/L and α-viniferin 324 μg/L was reached on 9 day of fermentation. This work indicates that endophytic fungi A. stellifer AB4 is expected to be potential source of bioactive molecules t-resveratrol and α-viniferin.