Phytochemical Isolation and Antimicrobial, Thrombolytic, Anti-inflammatory, Analgesic, and Antidiarrheal Activities from the Shell of Commonly Available Citrus reticulata Blanco: Multifaceted Role of Polymethoxyflavones.

Abstract

Fruit wastes are becoming popular as treasures for drug discovery in different classes of therapeutics. This research aimed to investigate the phytochemicals and potential bioactivities, such as antimicrobial, thrombolytic, anti-inflammatory, analgesic, and antidiarrheal properties of commonly available mandarin orange (Citrus reticulata Blanco) peel through experimental and computational techniques. Extensive chromatographic and ¹H-NMR spectroscopic analysis was employed to isolate four purified compounds, which were characterized as tangeretin (A), nobiletin (B), limonin (C), and β-sitosterol (D). Furthermore, GC-MS/MS analysis detected over 90 compounds with a notable number of polymethoxyflavones, including nobiletin (29.04%), tangeretin (15.55%), artemetin (8.1%), 6-demethoxytangeretin (1.28%), sinensetin (0.95%), demethylnobiletin (0.14%), pebrellin (0.10%), and salvigenin (0.04%). Dichloromethane soluble fraction (DCMSF) exerted the highest antimicrobial potency Candia albicans against (20 mm zone of inhibition) in the disk diffusion assay method. The aqueous soluble fraction (AQSF) exhibited 34.71% and 48.14% inhibition in hypotonic solution-induced and heat-induced hemolysis in the membrane stabilizing assay. Similarly, the AQSF exhibited the highest anti-thrombotic property with 32.57% clot lysis. The investigated 3 doses of the methanolic extracts (100, 200, and 400 mg/kg body weight) exerted statistically significant in vivo central analgesic effects in a tail-flicking method in a time-dependent manner. Moreover, all the doses exhibited significant efficacy in inhibiting acetic acid-induced abdominal writhing and castor oil-induced diarrheal episodes in mouse models. The molecular docking studies corroborated the existing in vitro and in vivo findings by demonstrating better or comparable binding affinities toward the respective receptors and favorable pharmacokinetic properties and toxicological profiles. The present findings indicate that C. reticulata is a rich source of polymethoxyflavones, demonstrating potential efficacy against microbial infections, thrombosis, inflammation, pain, and diarrhea. Nonetheless, comprehensive phytochemical screening is imperative to identify additional bioactive compounds and evaluate their pharmacological effects against several chronic health conditions, grounded in their traditional uses and current evidence.