10-Gingerol, a component of rikkunshito, improves cisplatin-induced anorexia by inhibiting acylated ghrelin degradation

Rikkunshito (RKT), a Japanese traditional medicine, has been shown to stimulate food intake in rats with cisplatin-induced anorexia; however, the underlying mechanisms remain unknown. In this study, we investigated whether RKT is involved in the degradation of peripheral ghrelin. RKT inhibited decreases in plasma ghrelin level and enhanced acyl- to desacyl-ghrelin (A/D) ratio in cisplatin-treated rats. Several components of RKT demonstrated inhibitory activity against ghrelin deacylating enzymes. In addition, 10-gingerol, a component of RKT, inhibited exogenous ghrelin deacylation. Therefore, RKT may enhance plasma acyl-ghrelin level, at least in part, by inhibiting the circulating ghrelin degrading enzyme.

► Rikkunshito (RKT) has been shown to stimulate ghrelin level in cisplatin-treated rats. ► We hypothesised that an increase in ghrelin level would inhibit the ghrelin degradation process. ► We investigated the effects of RKT on ghrelin deacylation in normal and cisplatin-treated rats. ► RKT and its component 10-gingerol inhibit the degradation of acyl-ghrelin by carboxylesterase inhibition. ► Carboxylesterase inhibition improved cisplatin-induced anorexia.