Biocosmetic Potential of Xylaria psidii, an Endophyte of Aegle marmelos

Globally, there is an impetus for natural and safe cosmetics, with cosmeceutical companies mainly seeking ingredients that offer minimal side effects. Biocosmetics are derived from plants, animals, microorganisms (bacteria/fungi), which are generally considered safer than synthetic chemical entities. Skin-lightening or hyperpigmentation-reducing agents are in great demand, which is largely based on the inhibition of tyrosinase, an enzyme essential for melanin biosynthesis. Fungi, in particular, are a rich source of bioactive compounds used in pharmaceuticals and cosmeceuticals. To the best of our knowledge, this is the first report evaluating the tyrosinase inhibitory and antioxidant properties of endophytic fungi isolated from Aegle marmelos (L.) Corrêa, offering a novel perspective on the cosmetic potential of its microbial associates. A novel agar plate screening platform was used to preliminarily screen the recovered culturable endophytes, followed by a spectrophotometric assay. Extract of one isolate, #4-2AMLGP5-1, exhibited a significant reduction of o-monophenolase and o-diphenolase activity with an IC50 of 123.9 and 139.9 µg/ml, respectively, as compared to 94.5 and 103.6 µg/ml of Kojic acid. The isolate also demonstrated antioxidant potential in DPPH, ABTS, and H2O2 scavenging assays, with IC50 values of 107.5, 87.6, and 115.1 µg/ml, respectively, compared to controls, Quercetin, Trolox, and Ascorbic acid. Multi-locus phylogenetic analysis revealed isolate #4-2AMLGP5-1 as Xylaria psidii, which holds promise as a natural tyrosinase inhibitor with antioxidant properties for future commercial applications.