Phytochemical Fingerprinting of Nigerian Versus South African Loranthus micranthus Linn. Extracts and Their Antimicrobial Potentials Against Five Resistant Bacteria

Background: Loranthus micranthus has been traditionally used in ethnomedicine for managing diabetes, hypertension, and schizophrenia. In response to the escalating issue of antibiotic resistance and the desire for alternatives with fewer side effects, attention has shifted towards natural medicines. This study investigated phytochemical fingerprinting and antibacterial activity of the plant from both Nigeria and South Africa because samples from both countries are classified as African. Methods: Standard techniques, including thin-layer chromatography and ultra-high-performance liquid chromatography–mass spectrometry, were used for chemical fingerprint profiling. Minimum inhibitory concentrations assay evaluated the antimicrobial potential of extracts and standards. Results: Notably, thin-layer chromatography analysis unravelled an identical chemical signature for samples from both countries. Distinct colours indicated the presence of anthracene derivatives, coumarins, and phenolic carboxylic acids, among others. The ultra-performance liquid chromatography–mass spectrometry results mirrored that of the thin-layer chromatography, that is, identical chemical signature and identified peaks including but not limited to stearic acid, quercetin, isoreserpin, and tiamulin in the dichloromethane extracts. Meanwhile, the methanol extracts exhibited compounds like 4-hydroxyhygric acid, quercetin, and catechin-3’-glycoside, among others. The antibacterial activity against Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus strains, Escherichia coli, and Streptococcus pyogenes afforded minimum inhibitory concentration values of 1.5 × 10−2 mg/mL for all the bacterial strains except Streptococcus pyogenes with minimum inhibitory concentration = 7.5 × 10−3 mg/mL when compared with ciprofloxacin positive control with a minimum inhibitory concentration = 0.0039 mg/mL. Conclusion: The apparent mono-directional thin-layer chromatography, ultra-performance liquid chromatography–mass spectrometry chemical signature, as well as the minimum inhibitory concentration values obtained from all the samples supported the classification of Loranthus micranthus Linn from both countries as African, and the extracts have the potential to inhibit resistant Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus strains, Escherichia coli, and Streptococcus pyogenes species.