Pharmacognostic Standardization and In vitro Evaluation of Citrus sinensis (L.) Osbeck Fruit Peel Extract Against Selected Gram-Negative Organisms.

Abstract

The increasing prevalence of antibiotic-resistant bacterial infections has become a significant global health challenge, necessitating the exploration of alternative therapeutic approaches. This study aimed to standardize the Citrus sinensis (sweet orange) fruit peel, and investigate its anti-bacteria potential against selected Gram-negative organisms The peels were collected, authenticated, processed, and extracted using water and ethanol. Pharmacognostic analysis including morphological, microscopical, physicochemical, and phytochemical evaluations were carried out to establish quality. Anti-bacteria sensitivity testing was assessed using agar well diffusion and broth microdilution methods. The physicochemical results revealed a moisture content of 0.85%, total ash value of 4.25%, acid-insoluble ash of 1.32%, and the highest extractive value in water (18.45%). Qualitative and quantitative phytochemical screening showed the presence of flavonoids, tannins, saponins, alkaloids, steroids, and terpenoids, with saponins (59.94%) and tannins (27.17%) being the most abundant. The extracts demonstrated concentration-dependent inhibitory effects on all tested organisms, with inhibition zones ranging from 8.5–19 mm. Minimum inhibitory concentration (MIC) values were 50 mg/ml for E. coli and Klebsiella spp., and 100 mg/ml for P. aeruginosa. These findings indicate that C. sinensis peel possesses appreciable antimicrobial activity attributable to its rich phytochemical composition. The study highlights the potential of citrus peel, an abundant agricultural byproduct, as a natural and sustainable source of bioactive compounds with promising application in the development of alternative antimicrobial agents.