Preliminary phytochemical profiling and in vitro antibacterial activity of Lycium edgeworthii (Solanaceae) leaf extract against multidrug-resistant bacterial pathogens

The escalating global crisis of antimicrobial resistance (AMR) necessitates the urgent discovery of novel therapeutic agents from underexplored plant sources. The genus Lycium (Solanaceae) is renowned for its rich phytochemistry, yet Lycium edgeworthii Dunal remains scientifically unexplored. This study presents the first comprehensive phytochemical profiling and antibacterial evaluation of L. edgeworthii leaf ethanolic extract against clinically relevant multidrug-resistant (MDR) bacterial pathogens. The extract was prepared via Soxhlet extraction (yield: 8.7% w/w) and subjected to qualitative phytochemical screening using standard protocols. Antibacterial activity was evaluated against Gram-positive (Staphylococcus aureus MTCC 96, Bacillus subtilis MTCC 121) and Gram-negative (Escherichia coli MTCC 443, Pseudomonas aeruginosa MTCC 424) bacteria using agar well diffusion and resazurin-based microdilution broth assays to determine zones of inhibition (ZOI) and minimum inhibitory concentrations (MICs). Phytochemical analysis confirmed the presence of alkaloids, flavonoids, terpenoids, saponins, coumarins, and glycosides. The extract exhibited significant, dose-dependent antibacterial activity. In the well diffusion assay, the largest inhibition zone was observed against P. aeruginosa (12.3 ± 0.6 mm at 100 mg/mL). However, MIC determination revealed greater efficacy against S. aureus (MIC = 0.39 mg/mL) and E. coli (MIC = 0.78 mg/mL), with higher MICs for P. aeruginosa and B. subtilis (1.56 mg/mL). This discrepancy between ZOI and MIC highlights the importance of employing complementary assays and suggests differential compound diffusion properties. The ethanolic leaf extract of L. edgeworthii possesses a diverse phytochemical profile and demonstrates significant, broad-spectrum antibacterial activity in vitro. Its notable efficacy against MDR pathogens, particularly S. aureus and E. coli, validates its ethnobotanical potential and positions it as a promising candidate for bioassay-guided isolation of novel antimicrobial leads. Future studies should focus on compound characterization, mechanistic investigations, and cytotoxicity evaluation.