Antidiarrheal and Antinociceptive Effect of Litchi chinensis Peel Extract

Abstract

Litchi (Litchi chinensis) peel has been used in traditional medicine to treat diarrhea and pain. However, these uses have not been scientifically validated. This study aimed to chemically characterize the litchi peel crude extract (CE) and evaluate its antidiarrheal and antinociceptive effects. CE showed no apparent toxicity in the acute toxicity test (LD₅₀ > 2000 mg/kg p.o.). CE was fractionated using a Sephadex LH-20 column and chemically characterized by HPLC-ESI-MS. CE (ED₅₀ = 1.56 mg/kg p.o.) and its fractions showed antidiarrheal effects in the castor oil-induced model. CE showed antinociceptive effects (ED₅₀ = 160.27 mg/kg p.o.) in the acetic acid-induced writhing model. The main compounds found in CE were caffeic acid 4-O-glucoside, procyanidin A2, and prodelphinidin B3. These compounds showed high binding affinity (−ΔG) in docking studies with targets such as COX-1 (−8.60 kcal/mol), COX-2 (−6.20 kcal/mol), and μ-opioid receptor (−10.10 kcal/mol), suggesting they could contribute to the observed effects.