Selectivity of Current Extraction Techniques for Flavonoids from Plant Materials

Abstract

Flavonoids have a broad spectrum of established positive effects on human and animal health. They find an application in medicine for disease therapy and chemoprevention, whence the interest in flavonoids increases. In addition, they are used in food and cosmetic industries as pigments and biopreservatives. Plants are an inexhaustible source of flavonoids. The most important step of plant raw material processing is extraction and isolation of target compounds. The quality of an extract and efficiency of a procedure are influenced by several factors: Plant material and pre-extracting sample preparation, type of solvent, extraction technique, physicochemical conditions, etc. The present overview discusses the common problems and key challenges of the extraction procedures and the different mechanisms for selective extraction of flavonoids from different plant sources. In summary, there is no universal extraction method and each optimized procedure is individual for the respective plants. For an extraction technique to be selective, it must combine an optimal solvent or mixture of solvents with an appropriate technique. Last but not least, its optimization is important for a variety of applications. Moreover, when the selected method needs to be standardized, it must achieve acceptable degree of repeatability and reproducibility.

Extraction of Bioactive Compounds from Medicinal Plants and Herbs

“…EAE enhance the extraction efficiency due to the hydrolytic action of the enzymes on the components of the cell wall and membrane and the macromolecules inside the cell, which facilitate the release of the natural products. Cellulose, α-amylase, and pectinase are hydrolyzing enzymes usually employed in EAE [47,82]. This procedure is suitable for extracting various bioactive substances from plant matrices, but after filtration the obtained fraction is rich in small water-soluble molecules that include polyphenols and flavonoids [82].…”

“…Cellulose, α-amylase, and pectinase are hydrolyzing enzymes usually employed in EAE [47,82]. This procedure is suitable for extracting various bioactive substances from plant matrices, but after filtration the obtained fraction is rich in small water-soluble molecules that include polyphenols and flavonoids [82].…”

“…They can be simple phenols, benzoic and cinnamic acid derivatives, coumarins, tannins, lignins, lignans, and flavonoids [124]. Flavonoids are a group of plant constituents, the most common phenolic compound produce by plants as secondary metabolites in response to diverse biotic and abiotic factors [63,82,124]. They are responsible for the characteristics of flavor, color and pharmacological activities [67,80,125].…”

“…There is no universal extraction method and each optimized procedure is unique [82]. Due to the complex nature of the sample matrix and diverse chemical characteristics of flavonoids, it is consensual among scholars that there is no single or/and standard method to be used for every material or flavonoids to be extracted at present [67].…”

Catechin Hydrate Desorption From Newly-Synthesized Catechin-Loaded Biopolymer Particles

“…Catechins have been acknowledged as naturally derived biomolecules exhibiting profusive pharmacological and therapeutic activities like antiinflammatory, antimicrobial, antitumor, antiaging, antioxidant, etc. [1][2][3] This wide array of health effects, however, is significantly hampered due to the poor bioavailability, short half-life, stability issues, short shelf life, sensitivity to oxidation, limited gastrointestinal tract absorption and reduced biological activity of the bioflavanols [4]. Modern scientific studies have recently developed various advanced methodologies to surmount these limitations and to reveal the full therapeutic potential of catechins by modulation of innovative encapsulation technologies and subsequent release studies [5,6].…”