Antiviral and antioxidant potential of fungal endophytes of Egyptian medicinal plants

Abstract

This study aimed to explore the antioxidant potential and antiviral activity of endophytic fungi which were isolated from healthy living tissues of medicinal plants. Endophytic strains (29 different taxa) were isolated from 18 Egyptian medicinal plants collected from Saint Katherine Protectorate, Egypt. The fungal endophytes were identified based on morphological characters. All isolates were identified as ascomycetes, except two Zygomycetes strains (Absidia corymbifera and Mucor fuscus). Isolated endophytes were cultivated on potato dextrose media. The fungal metabolites were extracted by ethyl acetate and examined for their biological activities. Among 99 total extracts, only Chaetomium globosum, which was isolated from Adiantum capillus, showed a promising DPPH (1,1-diphenyl-2-picrylhydrazyl) scavenging activity (99% at 100 µg/mL). Fifteen extracts prohibited the reproduction of HSV-2 virus. On the other hand, the reproduction of VSV-virus was inhibited by sixteen endophytic extracts. The promising anti-(HSV-2 and VSV) extract of endophytic Pleospora tarda strain; that was originally isolated from the medicinal plant Ephedra aphylla, showed viral inhibitory activity of 40.7% and 15.2%, respectively. Two compounds, for which antiviral activates could be attributed, were isolated and identified as alternariol and alternariol-(9)-methyl ether using different NMR techniques from P. tarda extract. For the first time, we report here the ability of the endophytic fungus P. tarda to produce alternariol and alternariol-(9)-methyl ether. The results indicate that the endophytic fungi from medicinal plants are promising sources of bioactive compounds.