Sedative, Anxiolytic, Antinociceptive, Anti-inflammatory and Antipyretic Effects of a Chloroform Extract from the Leaves of Urena sinuata in Rodents

Context: Urena sinuate L. (Malvaceae) is a well-known medicinal plant and it is used in traditional medicine systems.

Objectives: The current study unravels the neuropharmacology, antinociceptive, anti-inflammatory and antipyretic effects of the chloroform extract of Urena sinuata leaves (CEUS) in rodents and also to determine the possible mechanism of antinociception which is involved in its acute toxicity and phytochemical studies.

Materials and Methods: Neuropharmacological activities of CEUS were performed by hole cross, open field test, elevated plus-maze test and Thiopental Na induced sleeping time test. For the analgesic activity of CEUS, different methods like hot plate test, acetic acid induced test, formalin-induced test, tail immersion test and glutamate-induced nociception were used. Additionally, a possible mechanism of nociception was identified by cyclic guanosine monophosphate (cGMP) and ATP-sensitive K+ channel pathway analysis. Carrageenan-induced rat paw edema and cotton pellet-induced granuloma test were conducted to detect anti-inflammatory activity and brewer's yeast induced pyrexia test for antipyretic activity. Before 60 min of subjection to the respective test, the extracts (200 and 400 mg/kg) were given orally.

Results: The obtained results showed that CEUS produced significantly (p < 0.05) neuropharmacological, anti-inflammatory and antipyretic activity with low or no toxicity. Moreover, in all the thermal and chemical-induced nociception models, antinociceptive response was exhibited. Furthermore, it involved cyclic guanosine monophosphate (cGMP) as well as ATP-sensitive K+ channel pathway mediated antinociceptive effect.

Conclusions: These data show that CEUS has significant neuropharmacological, anti-inflammatory and antipyretic effects that appear to have a relation with the inhibition of the glutamatergic system. Thus, the leaves of Urena sinuata could be used in the treatment of several types of inflammation in intestines and bladder.