Nitric oxide inhibitory substances from <i>Curcuma mangga</i> rhizomes

Abstract

Curcuma mangga Val. & Zijp. is a member of the Zingiberaceae family commonly grown in Thailand. It is locally known as mango tumeric because of its mango-like smell when the fresh rhizomes are cut. C. mangga is a popular vegetable, the tips of the young rhizomes and shoots are consumed raw with rice. Medicinally, the rhizomes are used as a stomachic and for chest pains, fever, and general debility. It is also used in postpartum care. In the present study, we investigated the anti-inflammatory effect of the extract and compounds from C. mangga rhizomes against lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW 264.7 cell line. From bioassay-guided fractionation, the chloroform fraction exhibited the most potent inhibitory activity with an IC50 value of 2.1 g/ml, followed by the hexane fraction (IC50 = 3.8 g/ml) and the ethyl acetate fraction (IC50 = 23.5 g/ml), respectively. Demethoxycurcumin (1) and 3-buten-2-one, 4-[(1R, 4aR, 8aR)-decahydro-5, 5, 8a-trimethyl-2-methylene-1-naphthalenyl]-, (3E)-rel- (2) were isolated from the chloroform- and hexane fractions, respectively. Bisdemethoxycurcumin (3) whose structure is similar to that of 1 was also tested for NO inhibitory activity. Of the tested compounds, compound 1 exhibited the highest activity with an IC50 value of 12.1 μM, followed by 3(IC50 = 16.9 M) and 2 (IC50 = 30.3 M). These results suggest that C. mangga and its compounds exert NO inhibitory activity and have a potential to be developed as a pharmaceutical preparation for treatment of inflammatory-related diseases. Moreover, this is the first report of compound 2 that was isolated from C. mangga rhizomes.

Keywords

• RAW264.7 cell
• nitric oxide
• <i>Curcuma mangga</i>
• Zingiberaceae