Fungal endophytes associated with mangroves – Chemistry and biopharmaceutical potential

Fungal endophytes are attracting much attention and increasingly recognized for their biopharmaceutical potential, especially when their host plants are traditionally used for their medicinal purposes. The relationship between endophytes and their host plants has fascinated many among us especially for their ability to produce structurally unique phytocompounds of significant biopharmaceutical and biomedical importance. This review attempts at providing a comprehensive account on the mangrove fungal endophytic community by compiling research and review articles (from 1990 to 2019). It also covers past and recent publications related to antioxidant, antimicrobial and cytotoxicity properties and emphasizing the potential of isolated metabolites from numerous mangrove fungal endophytes against a panel of human pathogenic microbes and cancer cell lines. It was found that mangrove endophytic fungi are capable to produce an impressive panoply of metabolites with promising biological activities including antioxidant, antimicrobial and anticancer. For instance, Sumalarins A–C isolated from Penicillium sumatrense of Lumnitzera racemosa Willd. and dimethylincisterol, ergosta-5,7,22-trien-3-ol, stigmast-4-en-3-one, stigmast-4-en-6,3-one, flufuran isolated from Pestalotiopsis sp. recovered from Rhizophora mucronata Lam. displayed potent cytotoxic activities against a panel of human cancer cell lines. However, there is still a dearth of knowledge that necessitates deeper investigation to further understand the relationship between mangrove endophytes and their host plants, especially those pertaining to phytochemicals. The endophytic fungi associated with mangroves are still at an infancy stage since only 27 mangrove species have been pharmacologically validated in terms of their endophytic fungi and thus this marked gap requires more in-depth investigations for a better understanding and clarification of their mechanisms of action.