Determination of Vitamin U in Vitamin U Preparations by a Potentiometric Titration Method / 中国药师

Objective:To improve the determination method of vitamin U in vitamin U preparations. Methods: A potentiometric titration method was established for the determination of vitamin U and the results were compared with those of the manual titration method described in the current quality standard. Results:The determination results of vitamin U by the potentiometric titration method were affected by neither the excipients and the other components contained in the preparations,nor the precipitation produced in the ti-tration process. The recoveries for two types of vitamin U ( methylmethinine sulfonium chloride and s-methy-L-methionine iodide) were 99. 47%(RSD=1. 0%,n=9) and 100. 22%(RSD=1. 4%,n=9), respectively. The determination results of 6 samples from 3 dif-ferent companies detected by the method were basically consistent to those detected by the manual titration method described in the cur-rent quality standards with the relative deviation less than or equal to 0. 5%. Conclusion:The method is simple,accurate and reliable, and can be used for the quantitative determination of vitamin U in various vitamin U preparations.

Determination of Vitamin U in Vitamin U Preparations by a Potentiometric Titration Method / 中国药师

Objective:To improve the determination method of vitamin U in vitamin U preparations. Methods: A potentiometric titration method was established for the determination of vitamin U and the results were compared with those of the manual titration method described in the current quality standard. Results:The determination results of vitamin U by the potentiometric titration method were affected by neither the excipients and the other components contained in the preparations,nor the precipitation produced in the ti-tration process. The recoveries for two types of vitamin U ( methylmethinine sulfonium chloride and s-methy-L-methionine iodide) were 99. 47%(RSD=1. 0%,n=9) and 100. 22%(RSD=1. 4%,n=9), respectively. The determination results of 6 samples from 3 dif-ferent companies detected by the method were basically consistent to those detected by the manual titration method described in the cur-rent quality standards with the relative deviation less than or equal to 0. 5%. Conclusion:The method is simple,accurate and reliable, and can be used for the quantitative determination of vitamin U in various vitamin U preparations.

Effect of Enhancers on in vitro and in vivo Skin Permeation and Deposition of S-Methyl-(L)-Methionine

S-methyl-(L)-methionine (SMM), also known as vitamin U, is commercially available as skin care cosmetic products for its wound healing and photoprotective effects. However, the low skin permeation expected of SMM due to its hydrophilic nature with a log P value of −3.3, has not been thoroughly addressed. The purpose of this study thus was to evaluate the effect of skin permeation enhancers on the skin permeation/deposition of SMM. Among the enhancers tested for the in vitro skin permeation and deposition of SMM, oleic acid showed the most significant enhancing effect. Moreover, the combination of oleic acid and ethanol further enhanced in vitro permeation and deposition of SMM through hairless mouse skin. Furthermore, the combination of oleic acid and ethanol significantly increased the in vivo deposition of SMM in the epidermis/dermis for 12 hr, which was high enough to exert a therapeutic effect. Therefore, based on the in vitro and in vivo studies, the combination of oleic acid and ethanol was shown to be effective in improving the topical skin delivery of SMM, which may be applied in the cosmetic production process for SMM.

Inhibitory Effect of Vitamin U (S-Methylmethionine Sulfonium Chloride) on Differentiation in 3T3-L1 Pre-adipocyte Cell Lines

BACKGROUND: S-methylmethionine sulfonium chloride was originally called vitamin U because of its inhibition of ulceration in the digestive system. Vitamin U is ubiquitously expressed in the tissues of flowering plants, and while there have been reports on its hypolipidemic effect, its precise function remains unknown. OBJECTIVE: This study was designed to evaluate the anti-obesity effect of vitamin U in 3T3-L1 pre-adipocyte cell lines. METHODS: We cultured the pre-adipocyte cell line 3T3L1 to overconfluency and then added fat differentiation-inducing media (dexamethasone, IBMX [isobutylmethylxanthine], insulin, indomethacin) and different concentrations (10, 50, 70, 90, 100 mM) of vitamin U. Then, we evaluated changes in the levels of triglycerides (TGs), glycerol-3-phosphate dehydrogenase (G3PDH), AMP-activated protein kinase (AMPK), adipocyte-specific markers (peroxisome proliferator-activated receptor gamma [PPAR-gamma], CCAAT/enhancer-binding protein alpha [C/EBP-alpha], adipocyte differentiation and determination factor 1 [ADD-1], adipsin, fatty acid synthase, lipoprotein lipase) and apoptosis-related signals (Bcl-2, Bax). RESULTS: There was a gradual decrease in the level of TGs, C/EBP-alpha, PPAR-gamma, adipsin, ADD-1 and GPDH activity with increasing concentrations of vitamin U. In contrast, we observed a significant increase in AMPK activity with increasing levels of vitamin U. The decrease in bcl-2 and increase in Bax observed with increasing concentrations of vitamin U in the media were not statistically significant. CONCLUSION: This study suggests that vitamin U inhibits adipocyte differentiation via down-regulation of adipogenic factors and up-regulation of AMPK activity.