Abstract:Ruili lemon is China geographical indication product with high nutritive and medicinal value, which is rich in vitamins, minerals, flavonoids and other nutritional substances. High-performance liquid chromatography was applied to determine Limonin and 9 flavonoids in lemon fruit widely cultivated in hot and humid climates of Yunnan Province. Limonin and Flavonoids exhibited a wide range of biological effects, including hypolipidemic effect, lowering blood pressure and anti-cancer. The results showed that there were significant differences in limonin and flavonoids at different Development stages.The content of limonin decreased gradually during the development stoags, but the content of limonin in the fruit was still higher than the threshold of human bitterness by 6.3 times in 210 days after the flowers. Diosmin in flavonoids was the highest among all maturity stages, which accounted for 83.26% ~ 84.61% of total flavonoids, followed by hesperidin and neo-hesperidin as the main flavanone accounting for 14.18%~15.45% of the total flavonoids. PMFs were detected at lowest levels in lemon fruit, which was only 0.008% ~ 0.89% of total flavonoids, and no tangeretin were detected. It is deduced that Yunnan hot and humid environment is conducive to the accumulation of diosmin components, but the accumulation and transformation mechanism of flavonoids needs further study.
