The antinociceptive property of Centella asiatica extracts is known but the analgesic activity of its bioactive constituent asiaticoside has not been reported. We evaluated the antinociceptive activity of orally (p. o.) administered asiaticoside (1, 3, 5, and 10 mg/kg) in mice using the 0.6% acetic acid-induced writhing test, the 2.5% formalin-induced paw licking test, and the hot plate test. The capsaicin- and glutamate-induced paw licking tests were employed to evaluate the involvement of the vanilloid and glutamatergic systems, respectively. Asiaticoside (3, 5, and 10 mg/kg, p. o.) reduced the rate of writhing (p < 0.0001) by 25.3, 47.8, and 53.9%, respectively, and increased the latency period (p < 0.05) on the hot plate at 60 min post-treatment until the end of the experiment. Moreover, asiaticoside (3, 5, and 10 mg/kg, p. o.) shortened the time spent in licking/biting the injected paw (p < 0.0001) in the early phase of the formalin test by 45.7, 51.4, and 52.7%, respectively, and in the late phase (p < 0.01) by 23.6, 40.5, and 50.6%, respectively. Antinociception induced by asiaticoside (10 mg/kg) was not antagonized by naloxone in both the 2.5% formalin-induced nociception and the hot plate test, indicating a nonparticipation of the opioidergic system. Asiaticoside (1, 3, 5, and 10 mg/kg, p. o.) reduced the duration of biting/licking the capsaicin-injected paw (p < 0.0001) by 40.5, 48.2, 59.5, and 63.5%, respectively. Moreover, asiaticoside (5 and 10 mg/kg) shortened the time spent in biting/licking the glutamate-injected paw (p < 0.01) by 29.9 and 48.6%, respectively. Therefore, asiaticoside (5 and 10 mg/kg, p. o.) induces antinociception possibly through the vanilloid and glutamatergic systems.

中文翻译：

---

积雪草苷在诱导伤害感受小鼠模型中的抗伤害活性

积雪草提取物的镇痛特性是已知的，但其生物活性成分积雪草苷的镇痛活性尚未报道。我们使用 0.6% 乙酸诱导的扭体试验、2.5% 福尔马林诱导的舔爪试验和热板测试。采用辣椒素和谷氨酸诱导的舔爪试验分别评估香草酸和谷氨酸能系统的参与。积雪草苷（3、5 和 10 mg/kg，口服）分别使扭体率 (p < 0.0001) 降低 25.3%、47.8 和 53.9%，并延长热板上的潜伏期 (p < 0.05)。处理后60分钟直至实验结束。此外，积雪草苷（3、5 和 10 mg/kg，口服）使福尔马林试验早期阶段舔/咬注射爪子的时间分别缩短了 45.7%、51.4 和 52.7%（p < 0.0001）。和后期 (p < 0.01) 分别增加 23.6%、40.5% 和 50.6%。在 2.5% 福尔马林诱导的伤害感受和热板试验中，积雪草苷 (10 mg/kg) 诱导的镇痛作用不被纳洛酮拮抗，表明阿片类药物系统不参与。积雪草苷（1、3、5 和 10 mg/kg，口服）分别使注射辣椒素的爪子咬/舔的持续时间（p < 0.0001）减少了 40.5%、48.2、59.5 和 63.5%。此外，积雪草苷（5 mg/kg 和 10 mg/kg）分别缩短了咬/舔注射谷氨酸的爪子的时间（p < 0.01）29.9% 和 48.6%。因此，积雪草苷（5 和 10 mg/kg，口服）可能通过香草酸和谷氨酸能系统诱导镇痛作用。