Microbial Bioactives
Microbial Bioactives | Online ISSN 2209-2161
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Volume 9 Number 1 2026
REVIEWS (Open Access)
Unlocking Nature’s Pharmacy: A Systematic Review and Meta-Analysis of Bioactive Secondary Metabolites from Microbial, Marine, and Plant Sources
Eyhab R. Al-samawy 1*, Mustafa Salah Hasan 2*
Microbial Bioactives 9 (1) 1-8 https://doi.org/10.25163/microbbioacts.9110605
Submitted: 26 October 2025 Revised: 23 December 2025 Accepted: 01 January 2026 Published: 03 January 2026
Abstract
Secondary metabolites (SMs), or natural products (NPs), are structurally diverse chemical compounds produced by microorganisms, plants, and marine organisms, playing a pivotal role in drug discovery. These metabolites, although not essential for the basic survival of the producing organisms, are crucial for ecological interactions, defense mechanisms, and intercellular communication. Over the last four decades, natural products have provided the chemical foundation for numerous therapeutic agents, accounting for over 75% of newly approved drugs between 1981 and 2019. Microorganisms, particularly fungi and Actinobacteria, remain the most prolific producers of bioactive SMs, generating compounds with antimicrobial, anticancer, and immunomodulatory activities. Endophytic fungi, which inhabit plant tissues without causing disease, offer a sustainable alternative for obtaining plant-derived compounds such as taxol and camptothecin. Marine microorganisms and microalgae, including filamentous cyanobacteria and dinoflagellates, present a largely untapped reservoir of structurally novel metabolites with unique pharmacological properties. Despite the rich potential, the expression of biosynthetic gene clusters (BGCs) is often silent under laboratory conditions, posing challenges for discovery and industrial-scale production. This systematic review and meta-analysis synthesize current knowledge on the sources, chemical diversity, and biological activities of SMs, highlighting strategies such as co-culturing, OSMAC approaches, and molecular genetic tools for enhancing metabolite discovery. The findings underscore the importance of exploring diverse ecological niches and advanced biotechnological interventions to accelerate the development of safe and effective therapeutics. This work provides a comprehensive overview of current trends, challenges, and future directions in natural product research, offering actionable insights for pharmaceutical innovation.
Keywords: Secondary metabolites, Natural products, Microorganisms, Marine bioactives, Endophytes, Drug discovery, Polyketides, Alkaloids
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