Metabolite profiling, In-vitro and insilico assessment of antibacterial and anticancer activities of Alternaria alternata endophytic in Jatropha heynei

Abstract

Abstract Endophytic fungi are the plant symbiont with highly diverse nature and poorly defined ecological importance in host fitness. Although there are the reports on the isolation and characterization of fungal endophytes from a variety of hosts, there is still no report of Alternaria alternata from Jatropha heynei. Among numerous natural alternative sources, fungal endophytes produce a wide range of structurally diverse bioactive metabolites including antibacterial and anticancer compounds. In this study, an endophytic A. alternata was isolated from J. heynei. The ethylacetate extract of A. alternata was characterized by QTOF-HRLCMS analysis resulted in detection of bioactive compounds include kigelinone, levofuraltadone with antibacterial property and 2-hydroxychrysophanol, isoathyriol, glycophymoline, columbianetin and kaempferol 3-O-β-D- galactoside with cytotoxic properties. The metabolites of A. alternata showed significant antibacterial activity against tested clinical bacterial strains by well diffusion method. The high zone of inhibition recorded against Gram positive Enterococcus faecalis (14 ± 00 mm), and Gram-negative Pseudomonas syringae (19.66 ± 0.57 mm) and Klebsiella pneumoniae (14.66 ± 0.57 mm). The in-vitro anticancer activity of fungal extract by MTT assay displayed significant cytotoxic effect towards Human lung carcinoma cancer cells (A549) with IC50 value of 393.52 µgml− 1 and no cytotoxic effect to Human breast cancer cells (MCF-7) was observed. Further, antibacterial and anticancer spectral compounds of A. alternata were subjected molecular docking analysis with antibacterial target proteins such as tellurite resistance protein (2JXU), Indole-3-acetaldehyde Dehydrogenase (5IUU), Alkyl hydroperoxide reductase (5Y63) and with anticancer target human apoptotic regulator protein (1G5M). Results of the docking study demonstrated that spectral compounds Kigelinone, Levofuraltadone, 2-Hydroxychrysophanol and Isoathyriol have significant binding modes, with the best binding energy score with their respective antibacterial and anticancer target proteins. The endophytic fungi A. alternata in J. heynei can be a promising fungus that has broad spectrum antibacterial activity and anticancer property may provide future insight towards the production of bioactive ompounds.