Extraction and characterization of phenolic compounds and their potential antioxidant activities

Abstract

For thousands of years, plant has been widely applied in the medical area and is an important part of human diet. A high content of nutrients could be found in all kinds of plants, and the most outstanding group of nutrients that attracts scientists’ attention is the high level of phenolic compounds. Due to the relationship between high phenolic compound content and high antioxidant capacity, plant extracts are expected to become a potential treatment for oxidation stress diseases including diabetes and cancer. However, according to the instability of phenolic compounds to light and oxygen, there are certain difficulties in the extraction of such compounds. But after many years of development, the extraction technology of phenolic compounds has been quite stable, and the only problem is how to obtain high-quality extracts with high efficiency. To further enhance the value of plant extracts, concentration and separation methods are often applied, and when detailed analysis is required, characterization methods including HPLC and LC/GC–MS will be applied to evaluate the number and type of phenolic compounds. A series of antioxidant assays are widely performed in numerous studies to test the antioxidant capacity of the plant extracts, which is also an important basis for evaluating value of extracts. This paper intends to provide a view of a variety of methods used in plants’ phenolic compound extraction, separation, and characterization. Furthermore, this review presents the advantages and disadvantages of techniques involved in phenolic compound research and provides selected representative bibliographic examples.

HPLC-DAD Phenolic Composition, Antioxidant, Anticholinesterase, Antidiabetic and Anti-quorum Sensing Properties of Bitter Kola (Garcinia kola) and Kolanut (Cola acuminata)

“…[48] The water and hydroethanol solvent are considered suitable for phenolic extraction from plant material especially from foods since they are green and non-toxic solvents and additionally, ultrasonic method is considered a green method for phenolic extraction. [49][50][51] The ultrasound-assisted method used in this study with a water-ethanol solvent is therefore suitable for the extraction of phenolic compounds from both plants as reflected in the amounts of the quantified phenolic compounds. The process of extracting phenolics from plant matrices is challenging and each step of extraction can influence the recovery of phenolic compounds, thus, selection of an appropriate extraction method is crucial to targeted phenolic compounds in good yields and amounts.…”

“…[63][64][65][66] Usually, there is a correlation between phenolic compounds and antioxidant capacity as well as ability to quench harmful reactive oxygen species and reactive nitrogen species and reduce oxidative stress diseases such as Alzheimer's disease and diabetes. [19,50] Alzheimer's Disease (AD) is a leading cause of death resulting from severe neurodegeneration. The cholinergic hypothesis suggests that inhibiting Acetylcholinesterase (AChE) and Butyrylcholinesterase (BChE) can relieve cholinergic functions by increasing the levels of acetylcholine in the synapse necessary for neurotransmission and this is a suitable strategy to overcome AD.…”

The Hepatoprotective Effect of Two Date Palm Fruit Cultivars’ Extracts: Green Optimization of the Extraction Process

“…Accordingly, the green use of water as a solvent in this study was assisted using three physical “factors”; time, temperature, and rotation to produce a “water bath-assisted extraction (WAE)” method. Generally, using WAE, combined with the three factors mentioned above, is typical for extracting natural products as these physical assists help to lessen the handling time and energy and to enlarge the natural extracts’ quality, quantity, and safety [ 45 ]. However, very few studies have applied pure water to extract date palm fruits with or without any physical aids.…”

Application of Doehlert Experimental Design for Optimization of a New-Based Hydrophilic Interaction Solid-Phase Extraction of Phenolic Acids from Olive Oils

“…They represent a large and diverse group of substances abundantly present in most fruits, herbs, and vegetables [ 1 ]. Phenolics are secondary metabolites that are naturally present in several different plants and fruits [ 1 , 2 ], as well as in olives and olive oils. Polyphenols provide an antioxidant capacity, which has many health effects and are expressed in the form of inhibiting the oxidative process by scavenging free radicals and reactive oxygen species, which can help prevent oxidative stress [ 2 ].…”

“…Phenolics are secondary metabolites that are naturally present in several different plants and fruits [ 1 , 2 ], as well as in olives and olive oils. Polyphenols provide an antioxidant capacity, which has many health effects and are expressed in the form of inhibiting the oxidative process by scavenging free radicals and reactive oxygen species, which can help prevent oxidative stress [ 2 ]. Many researchers had developed new methods for the identification and extraction of these polyphenols from natural and medicinal plants and agro-food products [ 3 , 4 , 5 ].…”