Effects of culture media on secondary metabolites production of Emericella variecolor Berk & Br.

Abstract

The objective of this research was to investigate effect of Malt extract broth (MEB), Malt Czapek-Dox broth (MCzB) and Czapek-Dox broth (CzB) on secondary metabolites of the endophytic fungus, Emericella variecolor Berk & Br. Metabolites of E. variecolor cultured in these three media were isolated from mycelia and broth and characterized by spectroscopic techniques. EtOAc crude of mycelium obtained from culture in MEB was isolated by column chromatography to obtain two known compounds, stellatic acid A, ergosterol B, and a novel sesterterpene, Emervaridione C1 while EtOAc crude from fermentation broth of culture in MEB was isolated to obtain two novel heptyl benzyl alcohols, varioxiranediol D1 and varitetraol A D2 and a known compound, dihydroterrein E. EtOAc crude of mycelium obtained from the culture in MCzB was isolated to obtain A, B, two known xanthones (14-methoxy tajixanthone 25-acetate F1, and tajixanthone hydrate F2), two known anthraquinones (1-hydroxy-6,8-dimethoxy-3-methylanthraquinone G1 and 4,6-dihydroxy-5,7-dimethoxy-2-methylanthraquinone G2) and two novel steroidal anthraquinones (evanthrasterol A H1 and evanthrasterol B H2), EtOAc crude of fermentation broth of the culture in MCzB was isolated to obtain two anthraquinones (G2 and dermoglaucin G3), two novel compounds (emervariodionin C2 and varitetraol B D3). EtOAc crude of mycelium obtained from culture in CzB was isolated to obtain A and B while EtOAc crude of fermentation broth extracted culture in CzB was isolated to obtain two novel compounds D3 and varitetraol C D4. The isolated metabolites were examined cytotoxic activity against HEP G2 (hepatoma), SW 20 (colon), CHAGO (lung), KATO-3 (gastric) and BT474 (braest) human cancer cell lines, antimicrobial and antioxidant activity. Compound F1 and F2 exhibited moderately cytotoxic activity and compounds G1, G2, G3, H1 and H2 were inactive.