EFFECT OF RICE BRAN OIL ON MYCELIAL BIOMASS PRODUCTION, BIOSYNTHESIS AND BIOACTIVITIES OF POLYSACCHARIDES BY OPHIOCORDYCEPS SINENSIS FUNGUS

Abstract

Ophiocordyceps sinensis (syn. Cordyceps sinensis), which is an entomopathogenic fungus, is widely known as “Dong Chong Xia Cao” in Traditional Chinese Medicine. It continues to attract scientists’ attention due to the diversity of bioactive compounds such as polysaccharides, cordycepin, adenosine, amino acids, peptides, and ergosterol. Among them, exopolysaccharides (EPS) from the culture broth has possessed many precious bioactivities, for example, immunomodulatory, antitumor, antioxidant activity, and etc. Interestingly, previous studies have demonstrated that plant oils have positive affects to the growth and biosynthesis of secondary metabolites of medicinal fungi. Therefore, the aim of this study is to enhance the biomass growth and EPS biosynthesis of O. sinensis fungus by implementing rice bran oil (RBO) at various concentrations from 1% to 8% (v/v) into the culture medium. The results illustrated that, in the RBO-added media, the biomass of mycelial and EPS production increased significantly compared to non-RBO medium. In particular, biomass yield was 26.6 g/L in medium within 6% RBO, and EPS production was 4.62 g/L in medium within 5% RBO. Importantly, inhibition of xanthine oxidase activity of the IPS and EPS crudes from the (2, 8% respectively). RBO-supplemented broths rose considerably compared to the control EPS. Besides, at 5% of RBO, the anti-inflammatory activity of EPS was highest with IC50 = 824.947 (µg/ml). In addition, the minimum IC50 value of IPS was 1529.061 (μg/ml) when added to the culture medium 4% RBO. In conclusion, these data have exposed evidence that the RBO was potential to dramatically exhibit the biomass production and EPS biosynthesis of O. sinensis fungus and improve their bioactivities.