Isolation, identification and antioxidant activity Aspergillus fumigatus HQD24 endophytic in Rhizophora mucronata

Abstract:

[Objective] Some of mangrove endophytic fungi inhabitated in special ecological which were enabled to secrete novel and biologically active compounds. In this study, an endophytic fungus HQD24 with antioxident activity was isolated from Rhizophora mucronata in Dong Zhai Gang-Mangrove Garden on Hainan Island and its antioxidant activity of crude extracts were evaluated. [Methods] Strain HQD24 was identified as Aspergillus fumigatus based on the morphological characteristic and ITS rDNA sequence analysis. Fermentation substrate were extracted with petroleum ether, chloroform, ethyl acetate and n-butanol successively. The antioxidant activity of were evaluated using radical scavenging activity on DPPH (2,2′-diphenyl-1-picrylhydrazyl) and ABTS (2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonicacid)), reducing Fe3+ capacity, chelating Fe2+ ability and superoxide radical-scavenging activity. [Results] The crude extract and all fractions possessed antioxidant and radical-scavenging activities in different assays. ABTS and superoxide radical-scavenging abilities were enhanced with the increase of the extract concentration. Chloroform fraction exhibited higher scavenging ability on ABTS radical reaches 71.92%, n-butanol fractions was found to be the most effective in superoxide radical scavenging reaches 62.36% with concentration of 1.5 g/L. The results indicating most of the antioxidant compounds of HQD24 are distributed in the chloroform and n-butanol fractions, followed by the ethyl acetate, and petroleum ether fraction. [Conclusion] Strain HQD24 was identified as Aspergillus fumigatus, which to be a promising resource with antioxidant activity for further investigation