Antimicrobial Action of Sambacus nigra, Symphytum officinale, Urtica dioica, and Mentha pulegium Plant Compounds against Antibiotic Resistant Streptococcus pneumoniae

Abstract

Infections by Streptococcus pneumoniae are among the leading causes of illness and death in children below 5 years, people with underlying debilitating medical conditions, and the elderly worldwide. Over the past three decades, antimicrobial resistance in S. pneumoniae has drastically increased, with resistance reported in Penicillin, erythromycin, trimethoprim/sulfamethoxazole, vancomycin, tetracycline, chloramphenicol and ofloxacin. This phenomenon has necessitated a continuous search for alternative compounds against S. pneumoniae, such as Plants. The objective was to investigate antimicrobial natural compounds present in S. nigra, S. officinale, U. dioica, and M. pulegium against antibiotic-resistant S. pneumoniae. The study utilised cross-sectional design where S. nigra leaves, S. officinale roots, U. dioica leaves, and M. pulegium leaves were collected from Kisii highland forests. Phytochemicals were identified by gas chromatography (GC/MS). Microbiological testing of the resistant strain of S. pneumoniae was done at Jaramogi Oginga Odinga Teaching and Referral Hospital Laboratory (JOOTRHL). The MBC and MIC were determined using disk diffusion. Data was analysed using ANOVA (P<0.05). Results showed alkaloids, phenols, tannins, flavonoids, saponins, glycosides, steroids and terpenoids at different extraction solvent concentrations. S. nigra, U. dioica, S. officinale and M. pulegium phytochemical compounds showed significant differences at 0.825 < 3.01. S. nigra and U. dioica showed considerable activity on resistant strains of S. pneumoniae. The MIC of S. nigra and U. dioica were 0.625 mg/L and 1.25 mg/L, while MBC was 0.3125 mg and 0.625 mg respectively. GC/MS analysis of phytochemical compounds on S. nigra and U. dioica showed a total of 8 NIST drug compounds. GC/MS study data; thymol, metharbital, Diethyltoluamide, Cyclohexanol, 5-methyl-2-(1-methylethyl)-, (1. alpha., 2. beta., 5. alpha.)-, aspirin, Piperonyl butoxide, triamterene and Glycine, N-benzoyl- are the most effective phytochemical compound in S. nigra and U. dioica against S. pneumoniae. The study concluded that S. nigra and U. dioica leaves pose active compounds that could be further used as alternatives in the treatment of antibiotic-resistant S. pneumoniae