COX 2 Inhibitory activity of Benjakul remedy and its compounds

Benjakul preparation has long been used as antiinflammatory drug in Thai traditional medicne. It compose of five plants, Piper retrofractum Vahl, Piper sarmentosum Roxb., Piper interruptum Opiz., Plumbago indica Linn. and Zingiber officinale Roscoe[1]. However, there is no report on anti-inflammatory effect of Benjakul extract on COX-2 inhibitory activity. Thus, the aim of this study was to investigate the anti-inflammatory activity of Benjakul remedy and compounds isolated from this remedy on COX2 inhibitory effect against prostaglandin E₂ (PGE2) release from RAW 264.7 macrophages [2]. Ethanol and water extracts of Benjakul were obtained by maceration in 95% ethanol and boiled in water, respectively. The extracts were tested for inhibitory activity on PEG2 release in RAW 264.7. The ethanol extract of Benjakul remedy showed high COX2 inhibitory effect; however, its activity is less than indomethacin as a positive control [IC₅₀ value of 5.82 and 0.28 µg/ml respectively]. The water extract had no activity. Five compounds were isolated from the ethanol extract of Benjakul remedy by bioassay-guided isolation: piperine (1), gingerol (2), plumbagin (3), methylpiperate (4) and myristicin (5). Compounds 3, 4, and 5 showed the highest COX2 inhibitory effect with IC₅₀ values of 0.08, 1.03 and 1.80 µg/ml, respectively. In conclusion, Benjakul remedy extract showed potent anti-inflammatory activity against PGE2 release from macrophages and the results further demonstrate that plumbagin, methylpiperate and myristicin should be used as anti-inflammatory markers for analysis of Benjakul extract.

Acknowledgements: This work was supported by the National Research University Project of Thailand Office of Higher Education Commission, Center of Excellence in Applied Thai Traditional Medicine, Faculty of Medicine, Thammasat University and National Research Council of Thailand.

Keywords: Benjakul, antinflammatory activity, COX-2, PEG2, Thai Traditional medicine.

References:

[1] Burodom, A., Itharat, A. Inflammatory suppressive effect of Benjakul, a Thai traditional medicine on intestinal epithelial cell line. J Med Plants Res 2013; 7: 3286 – 3291

[2] Nakatani K, Atsumi M, Arakawa T, Oosawa K, Shimura S, Nakahata N, Ohizumi Y. Inhibitions of histamine release and prostaglandin E2 synthesis by mangosteen, a Thai medicinal plant. Biol Pharm Bull 2002; 25:1137 – 1141