Aqueous Leaf Extracts of Lasianthera africana: Antibacterial activity, Acute Toxicity Testing, Effect on Gastrointestinal Microbiota and CD4+ T-lymphocyte Values of Wistar Rats Infected with Extensively Drug Resistant-Salmonella typhi

Abstract

The increasing resistance of microorganisms to antibiotics has created a need for therapeutic plants with strong antibacterial properties. The study determined the bioactive compounds, antibacterial efficacy, and acute toxicity testing (LD50) of aqueous leaf extracts of Lasianthera africana (ALELA) using gas chromatography-mass spectroscopy, disc diffusion technique, Reed and Muench, and Karber’s methods, respectively. The effect of ALELA on gastrointestinal microbiota and CD4+ values of Wistar rats with or without oral administration of ALELA and/or infected with extensively drug-resistant (XDR)- S. typhi were determined using standard protocol and the PimaTM CD4+ analyzer. The results showed that S. typhi exhibited extensively drug resistance. The ALELA had L-lactic acid, pent-4-enoic acid, 2-(2-hydroxy-3-isobutoxypropyl), and stigmastan-3, 5-diene in large amounts. The mean zone of inhibition, the MIC, and MBC values of ALELA ranged from 8.0 ± 0.0 to 18.2 ± 1.2 mm; 6.25 to 50 μg/mL and 6.25 to 100 μg/mL, respectively. The LD50 of ALELA was ≤ 2464 mg/kg, and there was a mean microbial load reduction from 4.2 ± 0.1 ×1010 to 9.7 ± 0.3 ×108 CFU/g in Wistar rats administered 1000 mg/kg ALELA and infected with XDR-S. typhi. The mean CD4+ values of Wistar rats administered with ALELA ranged from 8.2 ± 0.2 to 11.5 ± 0.5 cells/µL. The study has shown the antibacterial efficacy of ALELA against XDR-S. typhi and other gastro-intestinal flora in Wistar rats, suggesting its potential in treating bacterial gastrointestinal tract infections. Its mild toxicity suggests safety, while its effect on CD4+ T-lymphocyte values indicates immunomodulatory potential.