Isochromophilones H-K, the new bioactive azaphilone derivatives isolated from fungal strain Diaporthe perseae associated with Pongamia pinnata plant

The phytochemical study of the Diaporthe species has revealed significant classes of mycotoxins and phomopsins. Dihydroanthracenone derivatives, chromanones and isochromophilones have also been isolated from Diaporthe sp. These findings led us to explore the Diaporthe perseae for phytochemical analysis that resulted in the isolation of four new compounds designated as isochromophilones H-K (1–4), alongside three previously identified metabolites. Using extensive spectroscopic investigations such as NMR, and Mass spectroscopy, their structures were elucidated. Furthermore, the antimicrobial and anti-diabetic potentials of all isolated compounds were assessed. Compounds 1–3 demonstrated significant antibacterial activity, while compounds 4–7 exhibited comparatively lower effectiveness than the reference antibiotics. Compounds 2–3 showed potent diabetic inhibition, displaying IC50 values of 16.3 ± 0.3 and 25.4 ± 0.3, respectively. Compounds 1, 5, and 6 displayed mild anti-diabetic effects, with IC50 values of 56.5 ± 0.8, 37.6 ± 0.4, and 48.2 ± 0.6. However, compounds 4 and 7 were found least active. Bioactive azaphilone derivatives isolated from fungal strain Diaporthe per seae associated with Pongamia pinnata plant. [Display omitted] •Extraction of four new isochromophilones along with three known compounds from mangrove fungus Diaporthe perseae.•Purification of the compounds with silica gel and sephadex columns along with HPLC.•Characterization of the compounds with spectroscopic techniques, such as UV, NMR and Mass spectroscopy.•Assessment of the antibacterial and anti-diabetic potentials of the isolated compounds.