Connecting the Dots in Secondary Metabolite Detection for Next-Generation Therapeutics: Combating Antibiotic Resistance and Cytotoxic Challenges

Secondary metabolites (SMs) are the bioactive compounds produced mainly by microorganisms and fungi, comprising with ecological and physiological roles. They have been recognized as a primary clinically important source for antibiotics, anticancer agents, and immunosuppressants. However, with the increasing emergence of antibiotic resistance the situation has been intensified, and there is a need for novel natural products with antimicrobial and cytotoxic potential globally. This review depicts the need of microbial and fungal secondary metabolites, with the strong emphases on their biosynthesis, regulation, and therapeutic applications. Particular attention is given to fungal metabolites such as beauvericin, gliotoxin, and chaetoglobosins, which exhibit potent cytotoxic activity against tumor cells. Furthermore, the review also draws the picture of endophytic fungi contributing as an unexplored reservoir of new metabolites, with advances in genome mining, and CRISPR-Cas-based activation of silent gene clusters to promote the discovery of bioactive compounds. The antimicrobial and cytotoxic functions together of several secondary metabolites underline their potential as next-generation therapeutics. Understanding their biogenesis, mechanism of action, and resistance modulation can significantly contribute to combating infectious and neoplastic diseases in the post-antibiotic era.