The pervasive rise of antimicrobial resistance has reinvigorated scientific interest in plant‑derived compounds as alternative or complementary antimicrobial agents. Medicinal plants such as Andrographis paniculata, Rauwolfia tetraphylla, and other species exhibit diverse bioactive secondary metabolites that confer significant antimicrobial properties. In addition, plant tissue culture technology, particularly induction of callus cultures, can enhance the yield of such metabolites, mitigating constraints associated with slow plant growth and overharvesting. This manuscript integrates historical pharmacognostic knowledge with contemporary empirical research to assess and compare antimicrobial activity in natural plant extracts and their in‑vitro generated callus counterparts. Key methodologies for extraction, culture conditions, and antimicrobial evaluation (including disk diffusion and standardized assays) are examined, along with phytochemical characterization of active compounds. Results from multiple investigations reveal that callus extracts often exhibit higher phenolic and flavonoid content and enhanced antibacterial activity compared to leaf extracts, although variability exists depending on species and culture conditions. Furthermore, bioactive compounds such as andrographolide demonstrate efficacy against both Gram‑positive and Gram‑negative bacteria, with emerging data suggesting effects on resistant clinical isolates. Limitations in antifungal potency and variability among extraction protocols are also discussed. These findings support the integration of plant tissue culture and phytochemical screening as promising strategies for identifying novel antimicrobial agents amid escalating resistance patterns.

antimicrobial activity, Andrographis paniculata, callus culture, phytoconstituents, antibacterial efficacy, plant extracts

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