薬理と治療

Abstract

Objective　The aim of this study was to establish the functionality of oral ingestion of Kaempferia parviflora extract（SIRTMAX®）-containing diet and to examine the safety in case of excessive intake. Methods　The study was performed from July 2018 to January 2019. A randomized, double-blind, placebo-controlled parallel-group comparison study was performed on 30 healthy Japanese adults（15 males and 15 females）. All subjects were randomly allocated into the test product group（n＝15）or the placebo group（n＝15）using a computerized random-number generator. The subjects ingested either the placebo or the test product including 100 mg/day SIRTMAX® for 8 weeks, and the effects on fasting blood glucose level as a primary outcome, hemoglobin A1c（HbA1c）, glycoalbumin, insulin, and plasma pentosidine levels, vascular age, eye dryness, subjective symptoms, and sirtuin gene expression were examined. In addition, the subjects ingested 5 times the daily dosage of SIRTMAX®（ 500 mg╱day）for 4 weeks following the 8-week normal ingestion to examine the safety of excessive intake. Results　Twenty-eight subjects completed the trial and 14 subjects in each group were analyzed. In the efficacy test on all subjects, sirtuin expression showed increasing tendency（P＝0.08）in the test product group compared to that in the placebo group after the 8-week normal ingestion period. No other factors improved in the test product group compared to those in the placebo group. In the subgroup analysis, HbA1c level of the male test product group decreased significantly（P＝0.02）compared to that in the placebo group. In addition, the test product group showed a significant increase in Schirmer value in the left eye（P＝0.02）and non-dominant eye （P＝0.04） in the analysis of aged subjects. In the female test product group, “conspicuous crowʼs feet”“, dull skin（yellowish and brownish）”and“makeup sitting bad on skin”improved significantly compared to those in the placebo group after the 8-week normal ingestion period（P＝0.03, P＝0.007, and P＝0.008, respectively）. In the safety study, no adverse event was observed during the first 8 weeks of ingestion and the subsequent excessive ingestion for 4 weeks. Conclusion　The test product improved HbA1c level in healthy male adults and the amount of pertear in aged subjects. Moreover, the results suggested a significant improvement in skin condition such as wrinkles around eyes and makeup sitting in females. In addition, the test product appeared to be safe under the conditions employed in the present study. Trial Registration　UMIN-CTR: UMIN000033426 Funding　Tokiwa Phytochemical Co., Ltd.