I.The effects of extracts of Scutellaria radix, Paeoniae lactiflorae radix, and Gardenia fructus and their hydrolysates on melaninII.Determination of anthraquinone glycosides in Rhei rhizome, Polygoni multiflori radix, and Cassiae torae semen

• Main Authors: Hui-Ting Tsao, 曹惠婷
• Other Authors: Kuo-Ching Wen
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/82110154525342851291

碩士 === 中國醫藥大學 === 中國藥學研究所碩士班 === 95 === I. From the ancient times, humans prefer different skin colors and try diverse methods to modify them. Skin colors are related to the numbers, types and distribution of melanins, which are produced by the melanocyte on the basal layer of epidermal. In the process of melanins formation, tyrosinase dominates the rate limiting steps to transform tyrosine into dopaquinone. Nowadays, whitening agents as arbutin and hydroquinone are not satisfied, and scientists have been making an efforts to find whitening agents from natural products. According to the reports, aglycones have better bioactivity than glycosides. In this study, the decoctions and hydrolysates of Scutellaria radix (SR), Paeoniae lactiflorae radix (PLR), and Gardenia fructus (GF) on melanin synthesis were investigated. The inhibition activities were screened with mushroom tyrosinase, and then the effects on melanin formation and cell proliferation were investigated by mouse melanoma cells (B16-F0). The effects on the expression level of tyrosinase in B16-F0 cells were also carried out by western blot assay. The results showed that the hydrolysate of SR (IC50 18.6 mg/mL), decoction (IC50 17.0 mg/mL) and hydrolysate (IC50 7.3 mg/mL) of PLR, and decoction of GF (IC50 21.8 mg/mL) inhibited mushroom tyrosinase whereas the decoctions of SR and GF had little effects. However, all of these three decoctions had no effect on melanin formation. The hydrolysate of PLR inhibited melanogenesis whereas the hydrolysate of SR promoted it. As for tyrosinase in B16-F0 cells, the decoction and the hydrolysate of SR showed promoted effects, the hydrolysate of PLR showed inhibited effects, and the decoction of PLR and GF had little effects on it. In this study, the hydrolysate of PLR presents the strongest whitening effect by the inhibition of tyrosinase activity, and the hydrolysate of SR enhanced melanogenesis by promoting the activity and expression level of tyrosinase. II. Polyphenols are predominantly present as glycosides in Chinese herbs, and many of them are hydrolyzed to less polar aglycones by enzymes or bacteria in intestine and then became absorbable. Therefore, for quality control of Chinese herbs, the amount of total glycosides is more appropriate to serve as a standard since most glycosides are assimilated with aglycone form after oral administration. Currently there are limited requirements for the quality control of crude drugs in pharmacopoeias of many countries and only assay of one glycoside or aglycone are required. However, these requirements cannot ensure the efficacy of Chinese herbs. This study attempted to determine the contents of algycones in Rhei rhizome (RR), crude Polygoni multiflori radix (cPM), processed Polygoni multiflori radix (pPM), and Cassiae torae semen (CS) after acid hydrolysis to investigate the total amount of absorbable components. The decoctions of these four Chinese herbs were hydrolyzed by adding hydrochloric acid and heat. The contents of aloe-emodin, rhein, emodin, chrysophanol and physcion from RR, emodin and physcion from cPM and pPM, and chrysophanol and physcion from CS were determined by HPLC before and after hydrolysis. The total glycoside contents were calculated by subtracting the amounts of aglycones in decoction from those in hydrolysate. The results showed that the contents of aloe-emodin, emodin, and chrysophanol in RR after acid hydrolysis were increased by 154%, 145%, 127% and 95%, respectively. Emodin and physcion in cPM were increased by 1176% and 800%, respectively. Chrysophanol and physcion in CS existed solely as glycoside forms. However, emodin and physcion in pPM had no significant difference between decoction and hydrolysate. The methods developed in this study are applicable for the determination of total glycosides in RR, cPM, and CS, whereas pPM was suggested to determine the contents of aglycones directly.