Production of Non-Volatile Metabolites from Sooty Molds and Their Bio-Functionalities

Abstract

In the current study, eleven sooty mold isolates were collected from different tropical host plants. The isolates were identified under Capnodium, Leptoxyphium and Trichomerium, based on morphology and phylogeny. For the secondary metabolite analysis, the isolates were grown on Potato Dextrose Broth (PDB). The well-grown mycelia were filtered and extracted over methanol (MeOH). The metabolites in the growth medium (or filtrate) were extracted over ethyl acetate (EtOAc). The antifungal activities of each crude extract were tested over Alternaria sp., Colletotrichum sp., Curvularia sp., Fusarium sp. and Pestalotiopsis sp. The metabolites were further tested for their total phenolic, flavonoid and protein content prior to their antioxidant and anti-fungal potential evaluation. The MeOH extracts of sooty molds were enriched with proteins and specifically inhibited Curvularia sp. The total phenolic content and 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) activity was largely recovered from the filtrate corresponding to the inhibition of Alternaria sp.; while the flavonoid and free radical reduction suggested a relative induction of growth of the Fusarium sp., Colletotrichum sp. and Pestalotiopsis sp. Hence, this study reveals the diversity of sooty molds in Thailand by a modern phylogenetic approach. Furthermore, the preliminary screening of the isolates reveals the potential of finding novel compounds and providing insights for the future research on secondary metabolites of bio-trophic fungi and their potential usage on sustainable agriculture.