In vitro Antibacterial Potential of African Mistletoe (Tapinanthus bangwensis) against Gram-positive and Gram-negative Bacteria

Abstract

Background: The global rise in antimicrobial resistance (AMR) has intensified the search for alternative antimicrobial agents from plant sources. Tapinanthus bangwensis (African mistletoe) is widely used in traditional medicine, yet its antibacterial efficacy requires further scientific validation. Aim: This study investigated the comparative antibacterial efficacy of ethanolic and aqueous extracts of Tapinanthus bangwensis using quantitative in vitro assays against clinically relevant Gram-positive and Gram-negative bacterial pathogens. Methods: Plant extracts were prepared via cold maceration using ethanol and distilled water. Antibacterial activity was evaluated using the agar well diffusion method at concentrations of 25–100 mg/mL. Minimum inhibitory concentrations (MICs) were determined using the broth microdilution technique. Experiments were conducted in triplicate, and data were analyzed using one-way ANOVA with Tukey’s post hoc test at p < 0.05. Results: Both extracts exhibited concentration-dependent antibacterial activity, though the overall effect was limited. The ethanolic extract showed higher activity, with maximum inhibition zones of 8.3 ± 0.6 mm against S. aureus and 7.1 ± 0.5 mm against E. coli at 100 mg/mL. The aqueous extract demonstrated slightly lower activity. At concentrations ≤50 mg/mL, inhibition zones were comparable to the well diameter (6 mm), indicating minimal antibacterial effect. MIC values for both extracts were ≥50 mg/mL. In contrast, ciprofloxacin produced substantially larger inhibition zones (>21 mm). Statistical analysis indicated significant differences across concentrations (p < 0.05). Conclusion: Tapinanthus bangwensis exhibits weak but measurable antibacterial activity. Further studies involving purification and characterization of active compounds are required to elucidate its therapeutic potential.