Ching,F.P and Falodun, A.
Dept.of Pharmacology, Faculty of Basic Medical Sciences, Niger Delta University, Wilberforce Island, Yenagoa, Nigeria
Introduction: Stereospermum kunthianum is reputed for its ethnomedicinal use in the treatment of various painful and inflammatory conditions in Nigeria and other West African countries [1].
Materials and Methods: The chemical identification and isolation of the stem bark of Stereospermum kunthianum led to the isolation and characterization of an alklylated flavonoid (3,7,4/-trihydroxy-3/-(8//-acetoxy-7//-methyloctyl)-5,6-dimethoxyflavone. The structure was confirmed by 2-DNMR [2] and other spectroscopic techniques [3].
The analgesic and anti-inflammatory activities of the isolated compound were studied using the Randall-Selitto test [4], mouse writhing assay [5] and carrageenan-induced paw oedema in rats[6].
Results: Dimethoxyflavone at the dose of 25mg/kg and 50 mg/kg significantly increased (P < 0.001) the pain threshold when compared with the rats that similarly had sham treatment with distilled water. The percentage increase in pain threshold was 51.6, 66.7 and 62.3 respectively for dimethoxyflavone at 25 mg/kg, 50 mg/kg and indomethacin (10 mg/kg) respectively. In the mouse writhing assay, the writhes were significantly reduced (P < 0.001) in the dimethoxyflavone treated mice with the percentage inhibition of pain of 46.2, 58.3 and 63.1 for the flavonoid at 25 mg/kg, 50 mg/kg and aspirin (100 mg/kg) respectively. Dimethoxyflavone (25mg/kg and 50 mg/kg) caused a significant reduction (P <0.001) in the paw swelling as from the 2nd h and a much more reduction at the 3rd h post carrageenan injection compared with control rats.
Conclusion: The result of the phytochemical study led to the isolation of 3,7,4/-trihydroxy-3/-(8//-acetoxy-7//- methyloctyl)-5,6-dimethoxyflavone, a known flavonoid from Stereospermum. kunthianum stem bark which possesses both analgesic and antiinflammatory activities.
REFERENCES
[1] L. Gill, Ethnomedicinal Uses of Plants in Nigeria. University of Benin Press, Nigeria, p223, (1992).
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Phytochemistry, 66, 1927, (2005).
[4] L. O. Randall, and J.J. Selitto. Arch Int. Pharmacodyn.111, 409, (1957).
[5] R. Koster, M. Anderson, E.J. De beer, Fed. Proc. 18: 412 (1959).
[6] C.A. Winter, E.A. Risley, G.W. Nuss, Proc. Soc. Exp. Med. 111: 544. (1962).