Study of factors influencing pressurised solvent extraction of polar steroids from plant material. Application to the recovery of withanolides

Total Phenols from Grape Leaves Counteract Cell Proliferation and Modulate Apoptosis-Related Gene Expression in MCF-7 and HepG2 Human Cancer Cell Lines

Grape leaves influence several biological activities in the cardiovascular system, acting as antioxidants. In this study, we aimed at evaluating the effect of ethanolic and water extracts from grape leaves grown in Algeria, obtained by accelerator solvent extraction (ASE), on cell proliferation. The amount of total phenols was determined using the modified Folin-Ciocalteu method, antioxidant activities were evaluated by the 2,2-diphenyl-l-picrylhydrazyl free radical (DPPH*) method and ^·OH radical scavenging using electron paramagnetic resonance (EPR) spectroscopy methods. Cell proliferation of HepG2 hepatocarcinoma, MCF-7 human breast cancer cells and vein human umbilical (HUVEC) cells, as control for normal cell growth, was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reduction assay (MTT). Apoptosis- related genes were determined by measuring Bax and Bcl-2 mRNA expression levels. Accelerator solvent extractor yield did not show significant difference between the two solvents (ethanol and water) (p > 0.05). Total phenolic content of water and ethanolic extracts was 55.41 ± 0.11 and 155.73 ± 1.20 mg of gallic acid equivalents/g of dry weight, respectively. Ethanolic extracts showed larger amounts of total phenols as compared to water extracts and interesting antioxidant activity. HepG2 and MCF-7 cell proliferation decreased with increasing concentration of extracts (0.5, 1, and 2 mg/mL) added to the culture during a period of 1⁻72 h. In addition, the expression of the pro-apoptotic gene Bax was increased and that of the anti-apoptotic gene Bcl-2 was decreased in a dose-dependent manner, when both MCF-7 and HepG2 cells were cultured with one of the two extracts for 72 h. None of the extracts elicited toxic effects on vein umbilical HUVEC cells, highlighting the high specificity of the antiproliferative effect, targeting only cancer cells. Finally, our results suggested that ASE crude extract from grape leaves represents a source of bioactive compounds such as phenols, with potential antioxidants activity, disclosing a novel antiproliferative effect affecting only HepG2 and MCF-7 tumor cells.

Rice bran nutraceutics: A comprehensive review

Agro-industry yields ample quantity of several byproducts with considerable importance. These byproducts are mostly under-utilized, often used as animal feed or rejected as waste; hence their true potential is not harnessed. The use of such superfluous resources is of not only economic significance but also a form of commercial recycling. Rice bran is an important byproduct of rice milling industry with a global potential of 29.3 million tons annually. It is gaining great attention of the researchers due to its nutrient-rich composition, easy availability, low cost, high antioxidant potential, and promising effects against several metabolic ailments. Bioactive components of rice bran, mainly γ-oryzanol, have been reported to possess antioxidant, anti-inflammatory, hypocholesterolemic, anti-diabetic, and anti-cancer activities. Rice bran oil contains appreciable quantities of bioactive components and has attained the status of "Heart oil" due to its cardiac-friendly chemical profile. Nutraceutics have successfully been extracted from rice bran using several extraction techniques such as solvent extraction, supercritical fluid extraction, microwave-, and ultrasonic-assisted extraction. Current paper is an attempt to highlight bioactive moieties of rice bran along with their extraction technologies and health benefits.

Pressurized liquid extraction as a green approach in food and herbal plants extraction: A review

Pressurized liquid extraction is a "green" technology for the extraction of nutraceuticals from foods and herbal plants. This review discusses the extraction principles and the optimization of the extraction parameters that improves the extraction efficiency. The use of different solvent mixtures and other extraction additives to enhance the efficiency of the extraction are discussed. Dynamic mode of extraction in Pressurized liquid extraction, and the use of combined and hyphenated sample preparation and analytical techniques are presented. This work discusses how different studies used Pressurized liquid extraction to enrich phenolic compounds, lignans, carotenoids, oils and lipids, essential oils and other nutraceuticals from foods and herbal plants.

Natural product isolation

Since the 1990s, interest in natural product research has increased considerably. Following several outstanding developments in the areas of separation methods, spectroscopic techniques, and sensitive bioassays, natural product research has gained new attention for providing novel chemical entities. This updated review deals with sample preparation and purification, recent extraction techniques used for natural product separation, liquid-solid and liquid-liquid isolation techniques, as well as multi-step chromatographic operations. It covers examples of papers published since the NPR review 'Modern separation methods' by Marston and Hostettmann,1 with major emphasis on methods developed and the research undertaken since 2000.

Protocols on safety, efficacy, standardization, and documentation of herbal medicine (IUPAC Technical Report)

This Technical Report compiles and analyzes the current scientific knowledge on herbal medicine and highlights the practical ways for ensuring the safety of herbal preparations and evaluating their claimed efficacy. Emphasis has been given to the methods for standardization of herbal medicine and the ways and means for moving forward to achieve the difficult goal of preparing herbal medicines of consistent quality and effects. Pragmatic approaches have been recommended to overcome the difficulties in (i) protecting intellectual property rights (IPR); (ii) producing safe, potent, standardized, and affordable herbal medicine; and (iii) documenting the knowledge base on herbal medicine in an easily accessible format.

Recent extraction techniques for natural products: microwave-assisted extraction and pressurised solvent extraction

In the last 10 years there has been an increased interest in using techniques involving microwave-assisted extraction and pressurised solvent extraction in analytical laboratories. This review gives a brief overview of both methods, and reports on their application to the extraction of natural products. The influence of parameters such as the nature of the solvent and volume, temperature, time and particle size of the matrix is discussed. Through numerous examples, it is demonstrated that both techniques allow reduced solvent consumption and shorter extraction times, while the extraction yields of the analytes are equivalent to or even higher than those obtained with conventional methods.