Phytochemical profiling, anti-virulence effects, and antibacterial mechanisms of Myrothamnus flabellifolius (Welw.) extracts

Myrothamnus flabellifolius, the "resurrection plant," traditionally used in southern Africa, shows strong potential for anti-virulence chemotherapy and for mitigating toxin-linked pathogenesis, reinforcing its enduring ethnomedicinal value.

to investigate the phytochemical composition, antibiofilm, cytoprotective and anti-haemolytic effects, and potential antibacterial mechanisms of the extracts.

Simultaneous extraction of plant material was done using hexane and aqueous acetone, followed by liquid-extraction of acetone extract. LC-MS was used for chemical profiling. Antioxidant activity was assessed. Haemolytic and cytoprotective activities were investigated against hydrogen peroxide and β-haemolytic pathogens. Antibacterial activity was assessed using broth micro-dilution, dehydrogenase and cell membrane disruption assays. Antibiofilm activity was investigated using the crystal violet, tetrazolium assays and evaluation of bacterial growth.

Taxifolin, eriodyctiol, quercetin were identified in the ethyl acetate subfractions of the leaves (LEA) and stems (SEA) and phytosterols in the hexane fractions of the leaves (LH) and stem (SH). LEA and SEA exhibited strong antioxidant activity and provided significant protection of erythrocytes against oxidative and pathogen-induced haemolysis. LEA and SEA were active against Pseudomonas aeruginosa (MIC = 160 μg/mL), LH showed similar activity against Staphylococcus aureus (MIC = 160 μg/mL). The extracts disrupted the bacterial cell envelopes and inhibited dehydrogenase-linked metabolisms. Sub-MIC of LH, SH, and SEA significantly reduced biofilm formation in P. aeruginosa and Streptococcus pyogenes, despite exerting minimal effects on planktonic growth.

M. flabellifolius shows strong multi-target antibacterial and sub-MIC antibiofilm activity, alongside notable antioxidant, cryoprotection and potential for addressing oxidative stress-linked ailments.