Assessment of Antidiarrheal Effect of Oleuropein Through µ-Oopioid Receptor Interaction Pathway: In Vivo and in Silico Studies

Abstract

Oleuropein (OLP), a compound predominantly found in olive leaves, has been known for its numerous biological activities, including antioxidant, anti-inflammatory, and antimicrobial properties. Despite its established therapeutic potential, its role in treating diarrhea has not been extensively explored. This study aimed to evaluate the antidiarrheal effects of OLP in an in vivo model and to investigate its molecular interactions using in silico docking studies, pharmacokinetic predictions, and toxicity analysis. In the in vivo study, castor oil was used to induce diarrhea in 3-day-old chicks, and the antidiarrheal effect of OLP was tested at doses of 10 and 20 mg/kg. The standard drug, loperamide (LOP) at 3 mg/kg, was used for comparison. The results showed that OLP at both doses significantly (p < 0.05) reduced diarrheal secretions and increased latency, with the 20 mg/kg dose demonstrating the most effective results. The combination of OLP (20 mg/kg) with LOP (3 mg/kg) further enhanced the antidiarrheal effect. In the in silico study, molecular docking revealed that both OLP and LOP exhibited strong binding affinities (BAs) to the key receptor, μ-opioid receptor associated with diarrhea, while OLP showed higher BA (‒8.9 kcal/mol) compared to LOP (‒8.7 kcal/mol). Pharmacokinetic analysis of OLP revealed favorable properties and toxicity studies revealed no acute toxicity, with an LD₅₀ of 2000 mg/kg. In conclusion, the findings suggest that OLP possesses significant antidiarrheal potential both in vivo and through receptor interaction, positioning it as a promising natural therapeutic agent for managing diarrhea. Further studies are warranted to fully elucidate its mechanisms of action and clinical applicability.