**2.11 Analgesic effect**

*P. integerrima* bark's methanolic extract significantly reduced the induced writhing in mice representing the painkiller potential in this plant. This attenuation of acetic acid-induced writhing at the dose of 100 mg/kg reflects the peripheral analgesic effect of plant extract [38]. *P. integerrima* gall's extract demonstrated significant analgesic effect against acid-induced writhing, formalin-induced pain, and thermal-induced central algesia. The extract also attenuated the thermalinduced pain [40]. The gall analgesic effect was due to the presence of analgesic flavonoids [41]. The *P. vera* leaves extract proved central and peripheral analgesic in animal models [42]. The oil of *P. atalantica* fruits attenuated acetic acid-induced writhing in rats [43]. The *P. atlantica* was also reported to have a good painker in another study [44, 45]. Pestagremic acid is one of the potential analgesic constitutes of the *P. integerrima* bark [46]. The oleoresin demonstrated the antiinflammatory effect while rest of the samples were devoid of analgesic potential [47]. The gold nanoparticles *P. integerrima* gall have been tested for analgesic effect at the tested doses of 10 and 20 in acetic acid-induced pain model. Results

*Pharmacological Investigation of Genus* Pistacia *DOI: http://dx.doi.org/10.5772/intechopen.97322*

demonstrated significant analgesic potential [48]. These research data reflect that this genus has central and peripheral analgesic potential. The opioids receptors mediate the central pain, while peripheral pain receptors or COX inhibition are responsible for the peripheral analgesic effect. The available synthetic drugs having a good analgesic effect but are associated with side effects like a peptic ulcer. To find the analgesic remedy free of side effects is a big challenge to the researcher in the current modern era. The above-tested extract or constitutes needs to inter in the clinical trial to find more useful analgesic drugs.
