Antinociceptive activity of cyclopeptide alkaloids isolated from Ziziphus oxyphylla Edgew (Rhamnaceae).

The current study was designed to evaluate the antinociceptive profile of five cyclopeptide alkaloids isolated from Ziziphus oxyphylla, including Oxyphylline-B 1, Oxyphylline C 2 Oxyphylline-D 3, Nummularin-C 4, and Nummularin-R 5. The effect was studied in acetic acid induced writhing and formalin induced flinching behavior tests, at 2.5 and 5mg/kg i.p. In the post-acetic acid induced writhing test, the compounds significantly ameliorated abdominal constrictions in a dose dependent manner, with compounds 1 and 5 showing 80.98% and 77.87% protection, respectively. When challenged in the formalin induced test, pretreatment of compounds significantly attenuated painful sensation in both phases. Moreover, compounds 1 and 5 were more effective with 45.32% and 75.32% for 1 and 36.77% and 71.10% protection for 5, in the 1st and 2nd phases respectively. The peripheral analgesia was strongly augmented by the central effects of these compounds. The current finding strongly supports the ethnomedicinal use of this valuable medicinal plant in various painful conditions.