- 著者
- 小林 正 康村 満枝
- 出版者
- Center for Academic Publications Japan
- 雑誌
- Journal of Nutritional Science and Vitaminology (ISSN:03014800)
- 巻号頁・発行日
- vol.19, no.2, pp.123-128, 1973 (Released:2009-04-28)
- 参考文献数
- 5
- 被引用文献数
- 10 18
In the irradiation of ergosterol, the effect of wavelength on the forma-tion of potential vitamin D2 (the sum of pre-D2 and vitamin D2) was investigated. Monochromatic UV rays obtained from a spectroirradiator were used for the irradiations and the yield of potential vitamin D2 was estimated by the GLC method as described previously (1). When an ergosterol solution in ethanol (1.0 mg/ml) was irradiated by mono-chromatic UV ray in the range 230-400mμ with the quantum of 4.0×108 erg/cm2, the figure of the relationship between yield of potential vitamin D2 and wavelengths of irradiating UV rays showed a mountain shape with a maximum at 295mμ. Ultraviolet rays in the range 285-310mμ were more effective than the other rays for the formation of potential vitamin D2 (yield: higher than 22%), whereas those either below 230mμ or above 330mμ were less effective (yield: lower than 3.5%). The gas chromatograms of TMS ethers of all the irradiated solutions showed the presence of peaks due to gyro- and isopyro-D2 (thermal cyclized products of pre-D2 and vitamin D2), lumisterol2, ergosterol and tachy-sterol2, although their peak area ratios were very different. The irradiations by various monochromatic UV rays with different quanta of energy were also examined, and the ray of 295mμ with quanta of 2.1-6.4×108 erg/cm2 was found to give the best yields of potential vitamin D2, between 31.5 and 33%. Further irradiations beyond the maxima effected a decrease in the yield.
- 著者
- 小林 正 康村 満枝 出海 裕子
- 出版者
- 公益社団法人 日本ビタミン学会
- 雑誌
- ビタミン (ISSN:0006386X)
- 巻号頁・発行日
- vol.49, no.9-10, pp.373-379, 1975-10-25 (Released:2018-03-06)
In order to clarify the influences of sunlight intensity on the yield of vitamin D by sunlight irradiation of provitamin D, an ergosterol solution was irradiated by sunlight under various circumstances and the yield of vitamin D_2 in the solution was determined according to the procedure described in the previous paper^<1)>. The results are summarized in the following : (1) When the ergosterol solution was irradiated by sunlight of fine days at Kobe in different seasons, yearly variation of the yields showed that these in summer were significantly higher than those in winter and that these in spring or autumn were nearly middle between the two classes ; (2) When the ergosterol solution was irradiated by sunlight of different weather's days at a same place in a same month, the yields of fine days were significantly higher than those of cloudy, smogy and rainy days ; (3) When the ergosterol soltuion was irradiated by sunlight of nearly same weather's days at different places in a same month, there were no significant difference each other except the cases of Shiga heights and Kobe in summer ; (4) There were significant correlations between the yields and the sunlight intensities of both 300〜400 and 300〜330nm ranges, and the correlation with these in the latter's range was higher than those in the former's ; (5) There was no significant correlatation between the yields estimated on fine days and the sulfur dioxide concentrations in atmosphere.