Lutein and lutein esters in marigold flowers by high performance chromatography

Lutein and lutein esters in marigold flowers was quantitatively determined by high performance chromatography (HPLC) with ODS-C18 column. A mixture of CH3CN-CH3OH-CH3COOCH2CH2 with volume ratio of 55:1:44 was used as mobile phase at a flow rate of 1.0mL/min and detection was carried out at 480 nm. The column temperature was about 20℃. The contents of lutein and lutein esters were determined by analytical curve of lutein since lutein and lutein esters have the same spectral characteristics. Determination results of hexane extracts and saponified samples of lutein show that the saponification transforms the esters into free lutein. The increase of the content of dipalmitate and palmitate stearate reveals that the reaction includes transesterifications.     

Utilisation of spontaneous emulsification to fabricate lutein‐loaded nanoemulsion‐based delivery systems: factors influencing particle size and colour

Factors influencing the formation and properties of lutein‐loaded nanoemulsions fabricated using spontaneous emulsification (SE) were investigated. Nanoemulsion formation depended on oil type: small droplets (diameter ≈ 200 nm) with a narrow monomodal particle size distribution (polydispersity index ≈ 0.23) could be formed using medium‐chain triglycerides (MCT), but not long‐chain triglycerides. Nanoemulsion formation also depended on surfactant type and concentration, with Tween 80 being the most effective surfactant. Optimisation of lutein‐loaded nanoemulsions formed by SE led to systems with a final composition of 10 wt% oil phase (0.12 wt% lutein + 9.88 wt% MCT), 10 wt% Tween 80, and 80 wt% aqueous phase. The nanoemulsions were stable to droplet aggregation when stored at ambient temperature for up to 1 month; however, some colour fading occurred due to lutein degradation. This study indicated the potential of nanoemulsion‐based delivery system fabricated using a low‐energy method for encapsulation and protection of lutein.     

超临界流体抗溶剂法制备叶黄素/羟丙甲纤维素邻苯二甲酸酯纳米微胶囊

Lutein was nano-encapsuled with hydroxypropylmethyl cellulose phthalate (HPMCP) to maintain its bioactivity and to avoid thermal/light degradation. Supercritical antisolvent precipitation was applied to prepare lutein/HPMCP nano-capsule. The effects of several operating parameters on the yield, lutein loading, encapsulation efficiency, particle size and particle size distribution of the nanocapsule were investigated. The mean diameter of nanocapsules ranged from 163 nm to 219 nm under appropriate experimental conditions. The result of scanning electron microscope showed that the nanocapsules were nearly spherical. The highest yield reached 95.35% when the initial concentration of lutein was saturated. The highest lutein loading of 15.80% and encapsulation efficiency of 88.41% were obtained under the conditions of 11 MPa, 40C and CHPMCP︰Clutein 5︰l. The results may pro-mote the application of lutein in food industry.     

万寿菊叶黄素提取分离研究

本文研究了由万寿菊提取叶黄素的条件,包括皂化处理NaOH浓度,提取时间与次数对提取效率的影响,并通过薄层层析对产品进行了分析。     

Provitamin‐A and xanthophyll carotenoids in vegetables and food grains of nutritional and medicinal importance

This study reports carotenoid composition of vegetables (n = 56), cereals (n = 12), pulses and legumes (n = 12), analysed by HPLC. It was hypothesised that food grains, like vegetables may be good sources of carotenoids. Amongst vegetables, higher level (mg/100 g dry weight) of lutein (210–419) was detected in green/red/capsicum and yellow zucchini, whilst zeaxanthin was dominant in kenaf (4.59). β‐Carotene (mg/100 g dry weight) was higher in green capsicum and kenaf (48,159) whilst carrot, ivy gourd and green capsicum contain α‐carotene (22–110). Amongst food grains, chickpea, split red gram and flaxseed contain higher levels (μg/100 g dry weight) of lutein (185–200) whilst zeaxanthin level was highest in puffed chickpea (1.8). Red unpolished parboiled rice was richest (μg/100 g dry weight) in β‐carotene (67.6) whilst whole black gram contained higher levels of α‐carotene (52.7). Thus, results indicate that chickpea and red unpolished parboiled rice are good sources of carotenoids. These carotenoid‐rich vegetables and grains may be exploited to meet the lutein and β‐carotene requirement.     

叶黄素分析方法研究进展

叶黄素是一种极具商业开发价值的天然类胡萝卜素,它具有保护视力、增强免疫力、抗氧化、抗肿瘤等良好的生物学功能,本文对国内外有关叶黄素的分析方法进行了综述。     

巯基-烯点击化学法合成两亲性叶黄素

叶黄素是一种含氧的类胡萝卜素,适量摄入叶黄素可以减少白内障的发生,叶黄素还可以调节人和动物的免疫能力并且具有预防癌症的作用,但是,叶黄素的低水溶性限制了其在食品和制药行业中的应用。本文研究了利用巯基-烯点击化学法对叶黄素进行亲水性修饰,为叶黄素的化学改性提供了一种新方法。首先以三乙胺为缚酸剂,使叶黄素与丙烯酰氯酯化反应得到两端以乙烯基为端基的中间体,再在紫外光照射下以2,2-二甲氧基-2-苯基苯乙酮为催化剂,使中间体与L-半胱氨酸通过巯基-烯点击化学反应在叶黄素的两端引入亲水性的氨基和羧基,得到两亲性叶黄素。通过UV、IR对产物进行表征,结果表明成功合成了两亲性叶黄素,通过TEM观察两亲性叶黄素在水中自组装形成球形胶束,平均粒径为85nm,有望会大大增加叶黄素在生物体内的吸收率。     

Determination of Lutein from Fruit and Vegetables Through an Alkaline Hydrolysis Extraction Method and HPLC Analysis

A simple and rapid analytical method for the determination of lutein content, successfully used for cereal matrices, was evaluated in fruit and vegetables. The method involved the determination of lutein after an alkaline hydrolysis of the sample matrix, followed by extraction with solvents and analysis by normal phase HPLC. The optimized method was simple, precise, and accurate and it was characterized by few steps that could prevent loss of lutein and its degradation. The optimized method was used to evaluate the lutein amounts in several fruit and vegetables. Rich sources of lutein were confirmed to be green vegetables such as parsley, spinach, chicory, chard, broccoli, courgette, and peas, even if in a range of variability. Taking into account the suggested reference values these vegetables can be stated as good sources of lutein.     

Supercritical CO2 extraction of pigment components with pharmaceutical importance from Chlorella vulgaris

BACKGROUND: Chlorella vulgaris is a green microalgae that contains various pigment components of carotenoids and chlorophylls. Supercritical CO₂ is widely used for extraction of pharmaceutical compounds because it is non‐oxic and easily separated from extracted material by simply depressurizing. In this work, pharmaceutical compounds from Chlorella vulgaris have been extracted using supercritical CO₂ with or without entrainer at various extraction conditions. RESULTS: Based on high performance liquid chromatography (HPLC) analysis, the extracts contained pigment components, such as lutein, β‐carotene, chlorophyll a and b. Higher extraction pressure and temperature promoted higher lutein extraction by supercritical CO₂. The optimum pressure and temperature for extraction were obtained as 50 MPa and 80 °C. Ethanol as an entrainer was more effective than acetone for the extraction of pigment components. Pigment components in the extract obtained by supercritical CO₂ with and without entrainer were compared with the extract obtained by a conventional extraction method. CONCLUSION: Supercritical CO₂ has been successfully applied for the extraction of pigment components from Chlorella vulgaris. Supercritical CO₂ enabled high selectivity for lutein extraction; however, the lutein yield was lower than that obtained by extraction using supercritical CO₂ with ethanol and soxhlet. Copyright © 2008 Society of Chemical Industry