Antibacterial and Phytochemical Analysis of Garden Egg (Solanum aethiopicum) Leaf on Bacterial Isolates Among Patients with Conjunctivitis

Background: Resistance of microorganisms to conventional antibiotic therapy have become a major global problem and a threat to the efficacious treatment of infectious diseases that affect the body. Medicinal Plants have been reported as Promising Sources of antibacterial drugs due to their potent biochemical active compounds. This study was carried out to identify the phytochemicals and assess the antibacterial activity of Solanum aethiopicum leaf extracts for potential treatment of systemic and ocular bacterial infections. Methods: This was a clinical study carried out using the convenient sampling method at the molecular laboratory and Department of Optometry Teaching clinic of the Federal University of Technology Owerri, Imo State, Nigeria. Ethanolic and Aqueous extracts of Solanum aethiopicum leaf were prepared using Soxhlet extraction and cold maceration methods respectively. Quantitative and qualitative phytochemical analysis of the extracts were carried out. Swabs were taken from the Conjunctiva of 20 subjects with infected eye. Bacteria species of gram positive and negative stains were isolated and cultured. The organisms were identified using the agar-well diffusion method. The leaf extracts were prepared at different concentrations of 100mg/ml, 50mg/ml, 25mg/ml, 12.5mg/ml and 6.25mg/ml. the antibacterial activities of the leaf extracts were tested against gram positive isolates which included Staphylococcus aureus, Streptococcus pyogenes, Micrococcus luteus, Bacilli spp. and the gram-negative isolates, namely, Klebsiella pneumoniae, Shigella flexneri, Enterobacter cloacae, and Escherichia coli. The zones of inhibition of the microbes were measured. The minimum inhibitory concentration (MIC) and minimum bacterial concentration (MBC) were determined. Ciprofloxacin, a standard antibiotic, was used as a positive control to determine the potency of the leaf extracts. Data was analyzed using t-test and ANOVA. Results: The phytochemical analysis revealed that the ethanol extract of Solanum aethiopicum contains greater content of bioactive ingredients in the order, flavonoid, saponin, oxalate, steroid, cardiac glycosides, hydrogen cyanide, tannin, alkaloid, Phytate and phenol. All tested isolate showed significant antibacterial activity with p value = 0.001. There was no significant difference in the antibacterial activity of ethanol and aqueous extracts P value= 0.056. There was a significant difference between the leaf extracts (ethanol and aqueous) and the positive control (Ciprofloxacin) P value 0.0001. On multiple comparison of the antibacterial activities of the ethanol extract, aqueous extract and the positive control on the gram positive and the gram-negative bacteria isolates, the gram-positive bacteria isolates were found to be more susceptible than the gram-negative bacteria stains P value = 0.001. Minimum inhibitory concentrations were significant across the aqueous extract, ethanol extract and positive control P value= 0.0001, with mean value 100mg/dl, 10.2mg/dl and 6.25mg/dl respectively. Discussion: The above results has revealed the order of superiority in the antibacterial efficacies of the extracts of Solanum aethiopicum and the control antibiotics; highlighting the ciprofloxacin as the highest, followed by the ethanol and aqueous extract with significant susceptibility of the gram-positive strains than the negative bacterial strains. Conclusion: The study concluded that the ethanoic and aqueous leaf extracts of Solanum aethiopicum could serve as a potent broad spectrum antibacterial agent for systemic and ocular bacterial infection. Recommendation: Studies should be carried out to assess other parts of the plant model. Key words: Solanum aethiopicum, Minimum inhibitory concentration, Minimum bacteria concentration.