Evaluation of Anti-inflammatory and Analgesic Effects of the n-hexane Fraction from Piper Betle Plant in Experimental Models

Abstract

Background: Piper betle L. plant has been reported to possess analgesic and anti-inflammatory properties; however, evidence regarding the in vivo pharmacological activity of their non-polar fraction remains limited. This study evaluated the analgesic and anti-inflammatory effects of the n-hexane fraction obtained from an ethanol fraction of Piper betle L. plant (PB-Hex) in experimental animals. Methods: The analgesic activity of PB-Hex was evaluated using the acetic acid-induced writhing test in Swiss albino mice. Animals received vehicle, aspirin at 100 mg/kg, or PB-Hex at 100 or 300 mg/kg orally once daily for five consecutive days. Anti-inflammatory activity was assessed in Wistar rats using carrageenan-induced paw edema and carrageenan–formaldehyde-induced peritonitis. Rats received vehicle, aspirin at 150 mg/kg, or PB-Hex at 50 or 150 mg/kg using the same treatment schedule. The evaluated outcomes included the number of writhing responses, changes in paw volume, percentage inhibition of paw edema, peritoneal exudate volume, protein concentration, and total leukocyte count. Results: PB-Hex-treated mice showed lower numbers of acetic acid-induced writhing responses than the vehicle-treated model control group, with a more consistent numerical effect at 100 mg/kg than at 300 mg/kg. In the carrageenan-induced paw-edema model, PB-Hex attenuated the increase in paw volume, particularly at 50 mg/kg, whereas the 150 mg/kg dose showed its greatest apparent effect at an earlier time point. In the peritonitis model, both PB-Hex doses were associated with lower peritoneal exudate volume, protein concentration, and total leukocyte count than the model control treatment. No clear dose-dependent response was observed across the experimental endpoints. Conclusion: PB-Hex showed preliminary analgesic and anti-inflammatory effects in the experimental models employed.