Investigating the Antimycobacterial, Antibiofilm, and Antioxidant Activities of Plant Extracts Against.
Ramokone Mothupi, Mashilo Matotoka, Gabriel Mashabela, Peter Masoko
Microorganisms · 2026-05
Abstract
The persistence ofwithin biofilm-like structures underscores the need for alternative drug discovery strategies aimed at resistance mechanisms. Medicinal plants provide a rich source of chemically diverse compounds with broad biological activities, including potential antimycobacterial properties. This study investigated acetone stem extracts from,, andsubsp.for their phytochemical composition, antioxidant capacity, and antimycobacterial activity against planktonic and biofilm forms of. Phytochemical profiles were analyzed using liquid chromatography-mass spectrometry and quantified through colorimetric assays. Antioxidant activity was assessed using DPPH radical scavenging and ferric reducing power assays, while antimycobacterial effects at MIC and sub-MIC levels were determined through microdilution and growth kinetic assays. Phytochemical composition and concentrations varied among extracts, withexhibiting the highest levels of tannins (287.18 ± 0.19 mgGAE/g extract) and flavonoids (16.48 ± 0.05 mgQE/g extract) and showing the strongest antioxidant activity (17.66 ± 5.396 and 399.1 ± 3.717 µg/mL).had a notable antimycobacterial activity with an MIC of 0.16 mg/mL followed byandsubsp.with MIC values of 0.31 and 0.63 mg/mL, respectively. All extracts significantly inhibited early biofilm formation by over 80% at sub-MICs. However, the mature biofilms and sliding motility were less susceptible to the extracts. Overall, the results confirm the antioxidant and antimycobacterial potential of the selected plant extracts, while highlighting challenges in targeting mycobacterial biofilms.