Human bitter taste-sensing type 2 receptors (hTAS2Rs) are expressed in various human tissues and may be associated with various cell signaling pathways, cell progression, and cell physiology in each tissue. hTAS2Rs can be a potential drug target because it is also expressed in some cancer cells. Xanthorrhizol (XNT) has various biological activities, such as anticancer, antimicrobial, anti-inflammatory, and antioxidant. XNT produces a bitter taste, but the specific hTAS2R activated is unknown, and the hTAS2R-mediated effect of XNT on cancer cells has not been studied. This study discovered the target receptor of XNT among 25 hTAS2Rs and confirmed the possibility of the hTAS2R-mediated inhibition of cancer cell proliferation. XNT activated only one receptor, hTAS2R38 (EC50=1.606±0.021 g/mL), and its activity was inhibited by probenecid, a hTAS2R38 antagonist. When HepG2 and MCF-7 cells were treated with XNT or phenylthiocarbamide (PTC), a known hTAS2R38 agonist, both chemicals inhibited cancer cell proliferation. XNT targets the human bitter taste receptor TAS2R38 and inhibits the proliferation of HepG2 and MCF-7 cells mediated by TAS2R38. This suggests that TAS2R38 may be a new target for disease treatment and a potential new factor for drug development.

The objective of this study was to evaluate the antifungal properties of xanthorrhizol (extract from curcuma xanthorrhiza) against Candida albicans. Some of the commercial products were evaluated for their ability to inhibit growth of C. albicans. OTC product containing povidone iodide and cosmetic grade product with surfactants were tested. Antifungal activity was shown in 1.56% of OTC product, however, there was no antifungal effect in cosmetic product. For the comparison, we tested several materials. Povidone iodide, lemon tea tree oil and xanthorrhizol showed antifungal activities against C albicans in 0.25, 0.062 and 0.007%, respectively. We also tested the antifungal effects of povidone iodide and xanthorrhizol in surfactant base. Test results revealed that 2.5% of povidone iodide and 0.156% of xanthorrhizol showed similar antifungal effects. These findings support the application of xanthorrhizol for vaginal cleanser or personal cares using antifungal effect.

Anti-microbiological effects of xanthorrhizol, ie., extract from curcuma xanthorrhiza and extract from houttuynia cordata Thunb. against influenza virus and E. coli O157 were tested. From the influenza experiments, the effects were shown above 93 % in case of houttuynia cordata Thunb. extract, however, the effects was not shown in case of xanthorrhizol. The effects were sustained in mixtures of houttuynia cordata Thunb. and curcuma xanthorrhiza extracts. We also tested the anti-microbiological effects of hand sanitizer containing houttuynia cordata Thunb. and xanthorrhizol. The effect of hand sanitizer containing 2,000 ppm of xanthorrhizol and 500 ppm of houttuynia cordata Thunb. extract was better than that of commercialized foreign product.