Antibacterial and Anti-Inflammatory Activities of Moringa oleifera: Extracts, Bioactive Compounds, and Mechanisms

Moringa oleifera (Moringaceae) is a tropical tree whose leaves and stems have long been used in South Asian and African traditional medicine for infectious and inflammatory disorders. These tissues contain a diverse array of secondary metabolites, chiefly flavonoids, phenolic acids, isothiocyanates, sterols, and peptides, and exhibit broad-spectrum antibacterial activity against Gram-positive and Gram-negative bacteria, including multidrug-resistant strains. Their anti-inflammatory effects have been attributed to the suppression of nuclear factor-κB (NF-κB)/Toll-like receptor 4 (TLR4) signaling and activation of the NF-E2-related factor 2 (Nrf2)/Kelch-like ECH-associated protein 1 (Keap1) antioxidant axis. This review synthesizes the phytochemistry of Moringa leaves and stems and critically evaluates current evidence for their antibacterial and anti-inflammatory activities, molecular targets, and potential crosstalk between the two. We further discuss extraction methods, structure–activity relationships, pharmacokinetics, safety, and applications spanning medicine, animal production, food preservation, and cosmetics. The evidence base is heterogeneous owing to variation in plant origin, extraction protocols, bacterial strains, and assay design; mechanistic and dosing data specific to leaves and stems remain preliminary. Across reports, leaf and stem extracts inhibit common Gram-positive and Gram-negative pathogens at MICs mostly in the approximate 0.2–4 mg/mL range, and isolated flavonoids and glucosinolate isothiocyanates act on bacterial membranes and quorum sensing and on host NF-κB/Nrf2 signaling; however, no study has formally quantified antibacterial–anti-inflammatory synergy within one assay system. Key gaps include standardized preparations, direct tests of antibacterial–anti-inflammatory synergy, systematic pharmacokinetic/pharmacodynamic and long-term safety studies, and high-quality clinical trials.