Endophytic fungi associated with Philippine endemic Annonaceae species yield extracts with anti-ESKAPE, antitubercular, and antioxidant activities

Rising cases of antibacterial resistance and oxidative stress-related disorders prompted the search for new compounds. In this study, endophytic fungi isolated from Philippine endemic Annonaceae plants were investigated as potential sources of antibiotic and antioxidant mycochemicals. Twelve isolates were cultured in four media (YM 6.3, ZM ½, Q6 ½, BRFT), extracted with ethyl acetate and methanol, yielding 48 crude extracts. Antibacterial activity was assessed using REMA for ESKAPE pathogens, and MABA MIC90 for Mycobacterium tuberculosis H37Rv, while antioxidant potential was determined via the DPPH assay. Twenty-three extracts were found to be inhibitory against ESKAPE pathogens, two against M. tuberculosis H37Rv, and 18 demonstrated free-radical scavenging properties. Morphological characterization and ITS-based phylogenetic analysis with MEGA X identified 11 distinct endophytic fungi as the sources of these bioactive extracts. Notably, the BRFT extract from Chromolaenicola sp. exhibited strong anti-ESKAPE activity (MIC = 250–7.81 µg/mL), while BRFT extracts from Diaporthe longicolla and Endomelanconiopsis sp. inhibited M. tuberculosis H37Rv by 90% and 96% at 64 µg/mL, respectively. In addition, the ZM extract from Chaetomium sp. (IC50 = 56.03 µg/mL) exhibited radical scavenging activity comparable to BHT (IC50 = 24.57 µg/mL), and ascorbic acid (IC50 = 1.18 µg/mL). Among the tested media, BRFT supported the highest metabolite production. Mycochemical screening revealed anthrones, terpenes, sterols, and indoles as major constituents. This study provides the first documentation of Chromolaenicola sp. and D. longicolla from O. cumingiana and Endomelanconiopsis sp. from A. cagayanensis, representing novel records of these genera in Annonaceae, and as promising sources of novel antibiotics and antioxidants.