Molecular profiling and antioxidant as well as anti-bacterial potential of polyphenol producing endophytic fungus-Aspergillus austroafricanus CGJ-B3

Abstract

Fungal endophytes are less studied group of microorganisms with vast therapeutic potential. A polyphenol producing endophyticfungus was isolated from Zingiber officinale rhizome. The ethyl acetate extract of Aspergillus austroafricanus (EAE) was tested against five human pathogenic bacteria by disc diffusion method. Antioxidant activity of EAE was determined by DPPH, H2O2 and nitric oxide radical-scavenging methods. DNA protection from the OH radicals was tested by agarose gel electrophoresis. High-performance liquid chromatography was used to determine the total yield of polyphenols. The identity of the endophytic fungus was established as A. austroafricanus CGJ-B3 (GenBank accession No. KT780617) based on rDNA and phylogenetic analysis. EAE showed significant antioxidant, antimicrobial activity and DNA damage protection capacity. The HPLC analysis showed the presence of polyphenols such as p-coumaric acid, ferulic acid and cinnamic acid and the content was about 0.392 ± 0.08 µg/mg, 4.35 ± 0.16 µg/mg and 1.976 ± 0.11 µg/mg, respectively. A. austroafricanus CGJ-B3 isolated from Z. officinale is a promising potential pharmaceutical agent and can be used as an alternative source of polyphenols like p-coumaric acid, ferulic acid and cinnamic acid.

Keywords

• Endophytic fungi
• Aspergillus austroafricanus CGJ-B3
• Zingiber officinale
• polyphenols
• antimicrobiol activity
• secondary metabolite