Phytochemical Analysis and Bioactivities of Dombeya rotundifolia and Lippia javanica

Tuberculosis (TB) remains a major global health challenge, compounded by rising drug resistance. Traditional medicinal plants used for TB-related symptoms represent a valuable yet underexplored source of potential antimycobacterial agents. In this study, the phytochemical content and biological activities of Dombeya rotundifolia and Lippia javanica were evaluated, and antimycobacterial compounds were isolated through bioassay-guided fractionation. Plant leaves were collected, extracted with solvents of varying polarity, and screened for phenolics and flavonoids. Antioxidant activity was assessed using DPPH and ferric reducing power assays, antimycobacterial activity was tested against Mycobacterium smegmatis, anti-inflammatory activity was determined by the egg albumin denaturation method, and cytotoxicity was evaluated in THP-1 cells using the MTT assay. Extraction yields varied, with water extracts of L. javanica showing the highest yield and hexane extracts of D. rotundifolia the lowest. Both plants contained bioactive phytochemicals with measurable antioxidant activity, while acetone and dichloromethane extracts of D. rotundifolia displayed the strongest antimycobacterial activity with MIC values of 0.16 mg/mL. Cytotoxicity assays indicated moderate toxicity at higher extract concentrations. Bioassay-guided isolation led to the identification of two fatty acid fractions with tentative characterization, which showed notable antimycobacterial activity (MIC 0.25 mg/mL). These findings provide preliminary support for the ethnomedicinal use of D. rotundifolia in respiratory conditions traditionally associated with tuberculosis and suggest a potential contribution of its fatty acids to its observed antimycobacterial activity.