维生素E琥珀酸酯的酶促合成及优化

在有机溶剂中以维生素E和琥珀酸酐为底物在脂肪酶的催化下合成了维生素E琥珀酸酯。首先对酶促反应的脂肪酶、反应介质和反应温度进行了考察,在所选的几种脂肪酶中,假丝酵母脂肪酶(Candidasp.)的催化活性最好;叔丁醇和DMSO组成的混合溶剂(体积比为2∶3)为最合适的反应介质;30℃为适宜的反应温度。并采用Box-Behnken实验设计和响应面因子分析法对底物摩尔比等其他反应条件进行了优化。维生素E琥珀酸酯最优反应条件为:维生素E浓度0.26mmol.ml-1,维生素E和琥珀酸酐摩尔比1∶5,在5ml叔丁醇和DMSO混合溶剂(体积比为2∶3)中,30℃下在0.02gCandidasp.脂肪酶的催化下反应71h,维生素E琥珀酸酯产率达到98.71%。     

维生素E琥珀酸酯的合成及其稳定性研究

以4-二甲氨基吡啶为催化剂,以维生素E和琥珀酸酐为原料合成维生素E琥珀酸酯.采用正交设计法对工艺进行优化,并采用HPLC法对产品进行了分析.研究了原料配比、催化剂用量、溶媒用量、反应温度、反应时间等因素对产率的影响及维生素E琥珀酸酯在不同贮藏条件下的稳定性.结果表明,在优化的条件下,维生素E琥珀酸酯的平均产率达88.57%;维生素E琥珀酸酯对光和热均不稳定,应在低温、避光条件下制备和保存.     

离子交换树脂法提纯维生素C磷酰化反应液

采用D301大孔弱碱阴离子交换树脂分离提纯维生素C磷酰化反应液.测定了室温下D301树脂吸附维生素C磷酸酯钠的动力学曲线和吸附等温线,考察了溶液pH值、温度、盐酸洗脱液浓度等因素对吸附的影响.最后用D301树脂对磷酰化反应液进行梯度洗脱,并用HPLC进行分析.结果表明D301树脂吸附维生素C磷酸酯钠约60 min达到平衡,Freundlich方程可以较好地描述树脂对维生素C磷酸酯钠的吸附.在室温下将磷酰化反应液调节pH至1～2后上柱吸附,依次用0.05 mol/L、0.2 mol/L、2.0 mol/L的盐酸溶液洗脱,收集0.2 mol/L盐酸洗脱液,用HPLC分析,结果其维生素C磷酸酯含量大于97%.     

加入维生素为个人洁肤品增值

综述了亚太地区的个人清洁用品市场 ,提出加入维生素来改善个人洁肤产品性能的概念。维生素E和泛醇 (维生素原B5)能够柔软皮肤并使皮肤不干燥。这些性能在香皂中已被气体轴承电动肌力计 (GasBearingElectrodymometer )试验所证实。在配方中 ,泛醇的用量范围为 2 %～5 % ,维生素E醋酸酯为 0 2 %～ 5 %     

维生素C与维生素E对辛基酚抑制效应的拮抗作用

探讨了辛基酚对活性污泥的抑制效应以及维生素C、维生素E单独和联合作用时对抑制效应的拮抗作用。实验结果表明,辛基酚浓度达到64 mg/L时,对本实验系统的活性污泥的比耗氧速率抑制率可达79.7%。维生素E对辛基酚抑制效应有较好的拮抗作用,而维生素C对辛基酚抑制效应的拮抗作用不明显,且高浓度反而会减弱污泥活性。低浓度维生素C与维生素E联合,对污泥抵抗辛基酚抑制效应起协同作用。     

3-O-乙基维生素C热稳定性及抗氧化性的研究

采用高效液相色谱法跟踪测定,评价3-0-乙基维生素C的热稳定性.通过清除有机自由基1,1-二苯基苦基苯肼(DPPH)法,评价3-0-乙基维生素C的抗氧化性能.结果表明:在水溶液中60℃保持6周后,3-0-乙基维生素C的保存率为95.5%,维生素C磷酸酯镁保存率为70.6%,维生素C保存率0.01%.维生素C、3-0-乙基维生素C、维生素C磷酸酯镁去除自由基DPPH的IC50值分别为8.42μg、10.35μg、163.44μg,维生素C、3-O-乙基维生素C、维生素C磷酸酯镁对自由基DPPH的实际清除量分别为2.82 g·g-1、2.29 g·g-1、0.15 g·g-1.     

高效液相色谱法测定脂溶性维生素的含量

采用高效液相色谱法，在C18柱上，以甲醇-乙酸乙酯(95／5，体积分数)为流动相，检测器波长为275nm，测定了维生素A醋酸酯，维生素D3和维生素E醋酸酯的含量。该方法简便、快速，用于实际样品测定，获得满意的结果。     

纳能托[注]超微载体系统的透皮性能研究

研究了质量分数为 2 %维生素E醋酸酯分别在纳能托[注 ] 超微载体系统、超小脂质体系统以及辛酸 /癸酸甘油三酯溶液中的体外活皮肤渗透性能。精确测定了皮肤不同深度层面区间中总维生素E以及纯维生素E的含量。研究发现 :含有维生素E醋酸酯的纳能托[注 ] 超微载体—天来达[注 ] E能够以其超小的体积 (d平均 <3 0nm )和紧密的结构有效通过人体皮肤的角质层屏障到达表皮层、真皮层、皮下组织以及深达 12 5 0 μm的皮肤脂肪层 ,并能够在皮肤中活性酶的作用下大量转化成为具有活性的纯维生素E (即维生素E醇 ) ,从而有效营养皮肤 ,防止皮肤细胞质的氧化及紫外线引起的自由基老化等     

菜籽油馏出物中维生素E的分子蒸馏工艺研究

介绍了菜籽油馏出物中维生素E的分子蒸馏工艺过程,考察了分子蒸馏各操作参数对维生素E的含量和收率的影响。研究结果表明:当操作压力为0.1Pa,蒸馏温度为180℃,进料流量250mL/h,进料温度170℃,刮膜速度150 r/min时,维生素E的一次收率可达65.38%,可得含量为51.72%的维生素E产品。利用分子蒸馏多级操作,可满足维生素E的进一步提纯要求。     

我国维生素工业现状及发展趋势

在维生素产品中 ,应用最为广泛的是维生素E、维生素C、维生素A、维生素B和维生素D。我国维生素特别是饲料级维生素依靠进口的局面现已完全改变 ,国内市场几乎所有的维生素由国内独资或合资企业生产 ,其中很大一部分出口 ,中国已成为国际市场重要的维生素供应商。我国维生素市场需求主要体现在饲料和保健品2方面 ,维生素保健品市场正快速形成 ,多维和预混料饲料用维生素产品增长快速。     

维生素C-K盐结晶工艺优化

以维生素C(VC)和K2CO3为主要原料,合成维生素C-K盐,最佳结晶条件为乙醇滴加量2∶1(乙醇量∶反应液量)、结晶温度-2℃、结晶时间6h。实验证明在此试验条件下,收率可提高到95%,含量99.6%以上。     

高效液相色谱法测定化妆品中VD2及VD3

采用高效液相色谱法对VD2及VD3进行测定,以甲醇/乙腈(90∶10)为流动相,流速为1.0 mL/min,DAD检测器,C18柱,检测波长260 nm,得到在0.50～50.0 mg/L浓度范围内有较好的线性关系,相关系数分别为rVD2=0.999 4和rVD3=0.999 5,回收率为96.9%～100.6%,方法检出限VD2为0.13 mg/L,VD3为0.06 mg/L。该方法快速方便,可用于化妆品VD2及VD3的检测。     

光化学合成维生素D2和D3

综述了光化学法合成维生素Ｄ２和Ｄ３的研究进展。     

化学修饰Novozym-435酶催化合成维生素E琥珀酸酯的研究

Vitamin E succinate was synthesized in organic solvents using a modified Novozym-435 as catalyst.In order to improve the catalytic performance of Novozym-435,the enzyme was modified using acetic anhydride, propionic anhydride and succinic anhydride separately.We found that both the hydrolytic activity and the thermal stability of the modified Novozym-435 were enhanced compared with the unmodified enzyme.The modified Novozym-435 catalysts were used to synthesize the succinate derivative of vitamin E.Compared with the native Novozym-435,the catalytic activity of the modified novozym-435 in promoting the synthesis of vitamin E succinate was dramatically increased,with the novozym-435 modified with succinic anhydride(N435-S)as the most active catalyst.Conditions for the synthesis of vitamin E succinate were also optimized.A mixture of tert-butanol and DMSO(volume ratio of 2︰3)was the most suitable medium for the reaction,whereas the appropriate molar ratio of vitamin E to succinic anhydride and reaction temperature were 1︰5 and 40°C,respectively.Under these reaction conditions,the yield of vitamin E succinate reached 94.4%.N435-S could be reused for five batches.     

Synthesis of Vitamin A Esters by Immobilized Candida sp. Lipase in Organic Media

Vitamin A ester was synthesized in organic solvents with immobilized lipase from Candida sp. The types of lipases, influences of solvent, the molar ratio of substrates, the reaction temperature and the water activity in the reaction were studied in detail in order to obtain the optimum conditions for Vitamin A palmitate synthesis. In a system of hexane, 100mg immobilized Candida sp. lipase was used in the presence of 1.2mmol vitamin A acetate and 3.6mmol palmitic acid. The yield of vitamin A palmitate reached 81% in 12h at 25℃. The immobilized Candida sp. lipase was prepared by adsorbing Cand/da sp. fermentation broth on pretreated textile and could be reused for at least six batches.     

降膜蒸发器在维C工业中的应用

用多效降膜蒸发器代替单效石墨列管升膜蒸发器对维Ｃ原料进行浓缩，解决了耐腐蚀的性能要求，不仅产品质量好，而且降低了操作费用和维护费用。对促进维Ｃ工业的发展与技术进步是很有意义的     

脂肪酶催化合成维生素A酯

研究了有机溶剂中脂肪酶催化合成维生素A酯。对催化合成维生素A棕榈酸酯反应的脂肪酶和反应介质进行了比较,同时对影响合成维生素A棕榈酸酯反应的因素(温度、初始水含量、底物摩尔比、反应时间和酶量等)进行了探讨,优化了反应条件:在10mL不含水分的正己烷中,0.200g维生素A醋酸酯和0.468g棕榈酸在酶量为10%(指固定化酶与维生素A醋酸酯的质量比)的固定化脂肪酶催化下,在30℃、190r/min下反应6h,转化率可以达到75%,固定化酶可连续使用6次以上。     

Vitamin D-Binding Protein and the Free Hormone Hypothesis for Vitamin D in Bio-Naïve Patients with Psoriasis

High levels of vitamin D-binding protein (DBP) have been reported in patients with psoriasis and the possibility of DBP as a marker of inflammation has been discussed. Furthermore, high DBP levels might negatively affect free 25(OH)D concentrations. According to the free hormone hypothesis, only the free fraction of a steroid hormone is capable of exerting biological action. Thus, free 25(OH)D level could be a better biomarker of vitamin D status than total 25(OH)D level. The objectives of this study were to identify the strongest determinants for DBP levels and to test the free hormone hypothesis for vitamin D in psoriasis. Additionally, we also aimed to investigate correlations between directly measured free 25(OH)D levels in serum and psoriasis disease severity compared to total 25(OH)D levels. This was a retrospective cross-sectional study including 40 bio-naïve patients with mild to severe plaque psoriasis. Psoriasis disease severity was evaluated using high sensitivity C-reactive protein (hsCRP), Psoriasis Area Severity Index (PASI) and visual analogue scale (VAS). Vitamin D metabolites including directly measured free 25(OH)D and serum DBP levels were measured. DBP levels were higher in patients with self-reported arthropathy than those without irrespective of confounding factors like sex, age and body weight. Total and free 25(OH)D levels correlated well (ρ = 0.77, p < 0.0001) and both were inversely correlated to intact parathyroid hormone (iPTH) (ρ = −0.33, p = 0.038 for total 25(OH)D and ρ = −0.40, p = 0.010 for free 25(OH)D). Only total 25(OH)D correlated to serum calcium levels (ρ = 0.32, p = 0.047). No correlations between any of the vitamin D metabolites and psoriasis disease severity were observed. In conclusion, DBP might be a new inflammatory biomarker in psoriasis, especially in psoriatic arthritis. Total 25(OH)D was a reliable measure for vitamin D status in this psoriasis cohort. However, evaluation of free 25(OH)D in patients with psoriatic disease and multiple co-morbidities and/or ongoing biologic treatment should be considered.