Analgesic activity of the ethanolic extract of Shorea robusta resin in experimental animals

Abstract

Aim:Shorea robusta (Sal), an important traditional Indian medicinal plant used in various ailments and rituals and the indigenous use of the resin of this plant as a medicament for treatment of various inflammatory conditions is well documented in literature. In the present study, ethanolic extract of S. robusta resin (SRE) was evaluated for its analgesic activity by making use of different central and peripheral pain models.Materials and Methods:The analgesic activity of SRE was assessed by employing different pain models such as, i) hot plate and tail flick tests for central analgesia, ii) acetic acid- induced writhing (peripheral analgesic model), iii) formalin-induced hind paw licking (both central and peripheral model), iv) carrageenan-induced hyperalgesia (peripheral analgesic model) and v) post-surgical pain (peripheral analgesic model).Results:The extract produced significant central and peripheral analgesic effects, as is evident from increase in reaction time in hot plate and tail flick tests, inhibition in writhing counts in acetic acid-induced writhing test, inhibition of licking time in formalin-induced hind paw licking, increased pain threshold in paw withdrawal latency in carrageenan-induced hyperalgesia and increased paw withdrawal threshold in post-surgical pain.Conclusion:The results of the present study demonstrate marked antinociceptive effects of SRE.

Analgesic Effect of 5-(3,4-Dihydroxyphenyl)-3-hydroxy-1-(2-hydroxyphenyl)penta-2,4-dien-1-one in Experimental Animal Models of Nociception

“…The acetic acid-induced abdominal constriction test is one of the most sensitive tests to evaluate the peripheral analgesic activities of novel drugs, compound, derivatives or synthetic substances [ 30 , 31 ]. However, the effects produced are usually deemed non-specific, as the writhing response could be attenuated by antihistamines, adrenergic blockers and muscle relaxants [ 32 , 33 ].…”

“…For instance, an intraperitoneal administration of acetic acid sensitizes the peripheral nociceptors producing pain as a result. The signals produced as a consequence to this event are transmitted to the central nervous system which will trigger the liberation of pro-inflammatory mediators such as histamine, bradykinin, serotonin, prostaglandins, substance P and endogenous enzymes such as lipoxygenase (LOX) and cyclooxygenase (COX-1 and COX-2) into the peritoneal fluid [ 30 , 31 ]. This series of events further sensitizes the nociceptors and the cycle is repeated until the algogenic agent or irritant is removed from the system or site of injury.…”

“…Consequently, neuropeptides such as substance P and bradykinin are released [ 38 , 39 , 40 ]. Pain produced during 0–5 min post formalin injection (neurogenic phase) may be mediated by the activation of transient receptor potential vanilloid 1 (TRPV1) [ 30 ]. During this phase, NSAIDs which specifically inhibit COX activity remain less effective in attenuating the nocifensive behaviour exhibited by mice compared to centrally-acting drugs such as morphine [ 41 ].…”

“…The hot-plate test is a thermally-induced pain model that evokes a spinal reflex or behavioural reaction and is often used to assess extracts or compounds that produces supra-spinal analgesia [ 30 , 34 ]. The present results showed that DHHPD at 1 and 3 mg/kg significantly prolonged the response latency in mice, confirming centrally-acting activities which correspond well with the results obtained from the formalin test.…”

Studies on analgesic, anti-inflammatory activities of stem and roots of Inula cuspidata C.B Clarke

“…It is well known fact that, the response (paw licking, jumping) by mice to noxious thermal stimuli in hot plate method is supra-spinally mediated response. 29 The analgesic effect exhibited by the extracts in hot plate test could be due to their interaction with various receptors present in supra-spinal sites.…”