Preparative separation of phytosterol analogues from green alga Chlorella vulgaris using recycling counter-current chromatography

An Integrated Chromatographic Strategy for the Large-Scale Extraction of Ergosterol from Tulasnellaceae sp

A reliable chromatographic strategy is crucial for the extraction of target compounds from natural sources as it is related to the preparation efficiency, as well as the purity of the compounds. In this study, medium-pressure normal-phase liquid chromatography and high-pressure reverse-phase liquid chromatography were combined to prepare and purify ergosterol from Tulasnellaceae sp. of Gymnadenia orchidis. First, Tulasnellaceae sp. was extracted three times (2.0 L and 2 h each time) with ethyl acetate, and the 6.0 L of extract solution was concentrated under reduced pressure to yield 2.2 g of crude sample. Then, the crude sample was pretreated utilizing silica gel medium-pressure liquid chromatography to enrich the target ingredient (586.0 mg). Finally, high-pressure reversed-phase liquid chromatography was used to purify the target compound, and the compound was characterized as ergosterol (purity > 95%) using spectral data. Overall, the simple and reproducible integrated chromatographic strategy developed in this study has the potential for the large-scale purification of steroids for laboratory and even industrial research. To the best of our knowledge, this is also the first report of ergosterol in Tulasnellaceae sp.

Recovery and recycling of solvent of counter-current chromatography: The sample of isolation of zeaxanthin in the Lycium barbarum L. fruits

An efficient method of recovering and recycling solvent for counter-current chromatography was established by which zeaxanthin was separated from Lycium barbarum L. fruits. A column with activated carbon combined with high performance counter-current chromatography formed the recovering and recycling solvent system. Using the solvent system of n-hexane-ethyl acetate-ethanol-water (8:2:7:3, v/v) from the references, five injections were performed with an almost unchanged purity of zeaxanthin (80.9, 81.2, 81.5, 81.3, and 80.2% respectively) in counter-current chromatography separation. Meanwhile, the mobile phase reduced by half than conventional counter-current chromatography. By this present method, an effective improvement of counter-current chromatography solvent utilization was achieved.

Potential of Chlorella as a Dietary Supplement to Promote Human Health

Chlorella is a green unicellular alga that is commercially produced and distributed worldwide as a dietary supplement. Chlorella products contain numerous nutrients and vitamins, including D and B12, that are absent in plant-derived food sources. Chlorella contains larger amounts of folate and iron than other plant-derived foods. Chlorella supplementation to mammals, including humans, has been reported to exhibit various pharmacological activities, including immunomodulatory, antioxidant, antidiabetic, antihypertensive, and antihyperlipidemic activities. Meta-analysis on the effects of Chlorella supplementation on cardiovascular risk factors have suggested that it improves total cholesterol levels, low-density lipoprotein cholesterol levels, systolic blood pressure, diastolic blood pressure, and fasting blood glucose levels but not triglycerides and high-density lipoprotein cholesterol levels. These beneficial effects of Chlorella might be due to synergism between multiple nutrient and antioxidant compounds. However, information regarding the bioactive compounds in Chlorella is limited.

Optimization extraction and purification of biological activity curcumin from Curcuma longa L by high-performance counter-current chromatography

The extraction condition of curcumin from Curcuma longa L was optimized through four factors and three levels orthogonal experiment based on the results of single factor tests. Under the optimal conditions: the concentration of ethanol  80%, extraction temperature 70°C, the ratio of liquid to material 20, and extraction time 3 h, a crude extract with the yield of curcumin 56.8 mg/g could be obtained. The isolation and purification of curcuminoids from the crude extract was performed on high performance counter current chromatography employing an optimized solvent system n-hexane/ethyl acetate/methanol/water (2/3/3/1, v/v/v/v). From 97 mg crude sample (in which the purity of curmumin was 68.56%), 67 mg curmumin, 18 mg demethoxycurcumin, and 9.7 mg bisdemethoxycurcumin with a high-performance liquid chromatography purity of 98.26, 97.39, and 98.67%, respectively, were obtained within 70 min. The antioxidant activities and cytotoxicity of purified curcumin was comparable to that of the commercial product, indicating that the biological activity of curcumin could be maintained by this method.