Antimicrobial secondary metabolites and antioxidant activities of fungal endophytes associated with <i>Ziziphus spina-christi</i> (L.) Desf. (Nabq) leaves

Abstract

A total of 20 endophytic fungi were isolated (ZSEFL1-ZSEFL20) from <i>Ziziphus spina-christi</i> (L.) Desf. (Nabq) leaves. Four isolates A2/ZSEFL2, <i>Alternaria alternata</i>, D/ZSEFL14, <i>Aspergillus niger</i>, E/ZSEFL15, <i>Epicoccum nigrum</i>, and S/ZSEFL19, <i>Penicillium crustosum</i> were found to show the most promising antimicrobial activities either in plug or disc diffusion screening assays against Gram-positive, Gram-negative bacteria and pathogenic fungi. Antimicrobial activity was tested against <i>Pseudomonas aeruginosa</i> ATCC 27853, <i>Staphylococcus aureus</i> ATCC 29213, <i>Serratia marcescens</i> ATCC 14764, <i>Klebsiella pneumonia</i>e ATCC 700603, <i>Candida albicans</i> ATCC 10231, and <i>Fusarium oxysporum</i> ATCC417. <i>In vitro</i> antioxidant activity assay was conducted using the ABTS [2,2'-Azino-bis (3-Ethylbenzthiazoline-6-Sulfonic Acid)] free radical scavenging method. EtOAc extracts of all isolated endophytic fungi showed antioxidant activities. This study would be one of the first reports to measure the antioxidant activity of <i>Z. spina-christi</i> (L.) Desf. endophytic fungi. Therefore, these isolated endophytic fungi can provide additional information for medicinal sources of natural antioxidants and antimicrobial agents.