Assessment of analgesic activity of Pterocarpus marsupium leaf extracts in Swiss albino mice

Introduction Traditional or herbal medicine worldwide is being reevaluated by extensive research on different plant species and their therapeutic principles. The major merits of traditional medicine seem to be their perceived efficacy, low incidence of serious adverse effects and comparatively low cost. Pterocarpus marsupium Roxb. (Leguminosae), commonly known as Bijayasara or Asana in Bengali, Bijasal in Hindi, Indian kino or Malabar kino in English, is a large deciduous tree widely distributed in the central, Western and Southern regions of India. It is an important medicinal plant of Indian traditional system of medicines and has been used in India for several medicinal purposes. It is a good source of tannins and hence used as powerful astringent and also in treatment of diarrhea and dysentery, passive haemorrhage, toothache and in diabetes. [1] It is also used as anti-inflammatory, anthelmintic, analgesic and in treatment of indigestion, diabetic anaemia, elephantiasis, erysipelas, urethrorrhea and ophthalmic complications. The role of P. marsupium as anti-diabetic has been very well established. [2] Its main chemical constituent is a glucosidal tannin namely kinotannic acid. Several other chemical constituents like pterostilbene, (-)-epicatechin, pterosupin, marsupsin, etc. have been identified and isolated. It also shows promising results in treatment of cataract and hypertriglyceridaemia. This plant also finds its use as cardiotonic and hepatoprotective agent. Studies have also been reported to demonstrate its ability as a specific COX-2 inhibitor. [3] Several pharmacological studies have been performed on this plant by the previous researchers. However, the analgesic assessment of successive petroleum ether, ethyl acetate and methanol extracts from P. marsupium leaf are still not reported. Therefore, in the present investigation we attempted these studies on the leaf extracts of P. marsupium.