Phytochemical profile, antibacterial activity and acute toxicity of Rhoicissus tridentata used to manage dog bites

Abstract

Dog bites often result into polymicrobial wound contamination, which pose several health risks including bacterial infections. In Uganda, Rhoicissus tridentata is traditionally used to manage dog bites, yet its secondary metabolite profile, antibacterial efficacy, and in-vivo toxicity had remained unexplored. Thus, the metabolites and the scientific evidence to validate the antibacterial activity and safety of the plant was limited. Identification of potent antibacterial agents could be crucial to manage dog-bite-related bacterial infections. The root extracts were analyzed using UHPLC–HRMS/MS—qTOF, followed by MZmine processing, and the metabolites characterized with GNPS Feature-Based Molecular Networking. For the first time, the high-resolution metabolomic approach resulted into annotation of 15 bioactive polyphenols like flavonoids, tannins. The antibacterial activity of the extracts was evaluated against standard strains of the zoonotic oral bacteria commonly associated with dog bites, namely: Enterococcus faecalis (ATCC 29,212), Streptococcus aureus (ATCC 25,932), Streptococcus mutans (ATCC 25,175), Proteus mirabilis (ATCC 25,933), Klebsiella pneumoniae (ATCC 700,603), and Escherichia coli (ATCC 25,922). The extracts exhibited moderate antibacterial activity against all the strains. The MIC and MBC ranged from (0.78 to 6.25) and (1.56 to 12.5) mg/mL respectively. The MBC/MIC ratios were between 1.9 and 2, signifying bactericidal extracts. In vivo acute toxicity testing, the extract showed no adverse signs of toxicity at doses up to 5000 mg/kg (LD50 > 5000 mg/kg), suggesting a favorable safety margin. These findings support the ethnopharmacological use of R. tridentata in managing dogbite-related bacterial infections and merit further investigations on its bioactive constituents identified for future antibacterial discovery.