In Vitro Anti-Inflammatory, Anti-Oxidant, and Cytotoxic Activities of Four Curcuma Species and the Isolation of Compounds from Curcuma aromatica Rhizome

The genus Curcuma is part of the Zingiberaceae family, and many Curcuma species have been used as traditional medicine and cosmetics in Thailand. To find new cosmeceutical ingredients, the in vitro anti-inflammatory, anti-oxidant, and cytotoxic activities of four Curcuma species as well as the isolation of compounds from the most active crude extract (C. aromatica) were investigated. The crude extract of C. aromatica showed 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity with an IC(50) value of 102.3 μg/mL. The cytotoxicity effect of C. aeruginosa, C. comosa, C. aromatica, and C. longa extracts assessed with the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay at 200 μg/mL were 12.1 ± 2.9, 14.4 ± 4.1, 28.6 ± 4.1, and 46.9 ± 8.6, respectively. C. aeruginosa and C. comosa presented apoptosis cells (57.7 ± 3.1% and 32.6 ± 2.2%, respectively) using the CytoTox-ONE™ assay. Different crude extracts or phytochemicals purified from C. aromatica were evaluated for their anti-inflammatory properties. The crude extract of C. aromatica showed the highest potential to inhibit NF-κB activity, followed by C. aeruginosa, C. comosa, and C. longa, respectively. Among the various purified phytochemicals curcumin, germacrone, curdione, zederone, and curcumenol significantly inhibited NF-κB activation in tumor necrosis factor (TNF) stimulated HaCaT keratinocytes. Of all compounds, curcumin was the most potent anti-inflammatory.