| Abstract: |
The accelerating global crisis of antimicrobial resistance has reinvigorated the search for novel antibacterial scaffolds, and medicinal plants remain among the most prolific reservoirs of such chemistry. This review presents a comprehensive meta-analytic synthesis of past work on the phytochemical diversity and antibacterial potential of higher plants published over the past three decades. A systematic search of PubMed, Scopus, Web of Science and ScienceDirect retrieved 1,248 records; after de-duplication, screening and full-text eligibility assessment, 92 peer-reviewed studies were retained for qualitative and quantitative synthesis. The surveyed literature covers 140 plant species from 48 families, with Lamiaceae, Fabaceae, Asteraceae and Euphorbiaceae most frequently represented, and evaluates activity against Gram-positive and Gram-negative pathogens, including resistant phenotypes such as methicillin-resistant Staphylococcus aureus and ESBL-producing enterobacteria. Major bioactive classes alkaloids, flavonoids, terpenoids, phenolic acids, tannins and saponins exert antibacterial effects principally through membrane disruption, efflux-pump interference, enzyme inhibition and anti-biofilm action. Reported minimum inhibitory concentrations vary widely owing to non-standardised extraction and assay protocols, a limitation critically appraised herein. Comparative analysis reveals that purified constituents generally outperform crude extracts, that Gram-positive organisms are more consistently susceptible, and that synergistic combinations with conventional antibiotics frequently restore susceptibility in resistant strains. Methodological heterogeneity, incomplete phytochemical characterisation and sparse in-vivo validation remain the principal deficiencies of past work. The review concludes with standardised research guidelines and outlines the translational pathway from ethnobotanical leads to clinically viable adjunctive antibacterials together with the priority gaps and reporting standards needed to make future studies directly comparable. |
