薬理と治療

Abstract

Objectives The aim of this study was to evaluate the efficacy of ripe kumquats on various effects such as natural killer（NK）cell activity, fatigue, and stress in healthy adults with fatigue. Methods In an open-label, uncontrolled exploratory study, 9 healthy subjects with fatigue consumed one kumquat per day for 4 weeks. The subjects were advised to restrict intake of foods containing rich β-cryptoxanthin（CRX）such as Satuma mandarin orange during the clinical study. The primary endpoint was NK cell activity. The secondary endpoints were efficacy:e. g., bone metabolism, fatigue-related scales, and health-related quality of life（QOL）, adverse events, and serum β-CRX levels. All tests were performed at weeks 0（baseline）, 1, and 4 after kumquat ingestion and at 4 weeks follow-up, except in the case of adverse events. Results NK cell activity and serum β-CRX levels significantly decreased after the 4-week ingestion period onwards. For efficacy assessment, the total scores on the Chalder fatigue scale were measured and the fatigue-related scales significantly improved after 1 and 4 weeks ingestion. Moreover, mental health component summary scores in the SF-36 as health-related QOL also significantly improved, starting from 1 week after ingestion. No adverse events were related to the kumquat ingestion. Conclusions Ingestion of one ripe kumquat per day decreased both NK cell activity and serum β-CRX levels because of low ingestion of kumquat. Meanwhile, kumquats may have anti-fatigue and anti-stress effects. Further clinical studies of ripe kumquat are needed to determine the optimal dosing and efficacy in placebo-controlled trials.