Abstract

The species, Herissantia crispa (L.) Brizicky, popularly known as malvaísco, is a plant belonging to the Malvaceae family. There are many reports on the pharmacological activity of other species of the Malvaceae family in traditional medicine showing anti-inflammatory, antinociceptive, and diuretic activities. In this study, the antinociceptive effect of the ethanol extract of H. crispa (EEHc) was observed in mice. The results showed that EEHc at all doses did not significantly change the latency to thermal stimulus 30, 60 or 120 min after treatment in the hot plate test. The EEHc in the acetic acid-induced writhing test, decreased significantly the number of contortions in the following doses: 250 (1.22 ± 0.57), 500 (2.2 ± 0.87) or 750 mg/kg (3.6 ± 1.42) as compared to the control group (17.78 ± 1.84). EEHc significantly reduced paw licking time at all doses tested in the early and late phase of the formalin test similar to the morphine treated group. The 750 mg/kg dose showed the best effect on phase 1 (54.33 ± 4.95) and phase 2 (13.5 ± 10.68) as compared to the control (95.3 ± 5.32 and 222.8 ± 23.39, subsequently). However, naloxone (NLX) did not reverse the antinociceptive effect of EEHc. Therefore, EEHc showed an antinociceptive activity, but this effect does not involve the opioid system.

Key words: Herissantia crispa, Malvaceae, antinociceptive activity, analgesia, natural product