Anti-Nociceptive and Anti-Inflammatory Activity of Hygrophila schulli Leaves

The management of pain and inflammation with non-steroidal anti-inflammatory drugs and opioid analgesics are currently encountering severe adverse reactions. To overcome these problems, herbal remedies may offer new alternative medicines. Hygrophila schulli is a medicinal plant traditionally used for the treatment of pain and inflammation-related disorders; yet, these claims are not scientifically validated. Hence, this study was aimed to validate the traditional use of Hygrophila schulli leaves as anti-inflammatory and analgesic remedy.

In vitro anti-hyaluronidase assay and in vivo carrageenan-induced hind paw oedema model were used to evaluate the anti-inflammatory property of ethanolic leaf extract of Hygrophila schulli. Tail immersion and acetic acid-induced writhing tests were performed to determine the central and peripheral analgesic activity of the leaf extract, respectively.

The ethanolic leaf extract exhibited significant anti-hyaluronidase activity (P<0.001) and significant inhibition of carrageenan-induced paw oedema (P<0.05) compared to untreated controls. Similarly, the extract significantly prolonged the reaction time of mice (P<0.05) for the hot-water stimuli. Furthermore, an oral dose of the extract showed significant inhibition (P<0.01) of acetic acid-induced abdominal contractions of mice. Besides, the ethanolic leaf extract did not cause any obvious sign of acute toxicity at a single oral dose of 2 g/kg.

The findings of this study may partially support the acclaimed traditional use of Hygrophila schulli leaves for the treatment of pain and inflammatory conditions.