What is the most efficient method for extracting bioactive compounds, particularly phenolics, from plant materials?

Answer from top 10 papers

The extraction of bioactive compounds, particularly phenolics, from plant materials is a significant area of research due to the potential health benefits these compounds offer. Microwave-assisted extraction (MAE) has been highlighted as an efficient technique for extracting phenolic compounds, as demonstrated in studies on torbangun leaves and Vernonia amygdalina leaf, where MAE yielded higher phenolic and flavonoid contents compared to conventional methods (Oman et al., 2013; Tanase et al., 2019). Additionally, the use of ethanol as a solvent in MAE has been shown to be effective in extracting a wide range of phytochemicals, including phenolics, from Moringa concanensis (Quintana et al., 2021).
Contradictorily, while MAE is efficient, other novel extraction techniques such as supercritical CO2 extraction and pressurised liquid extraction have been identified as sustainable and green methods, particularly effective for apolar and polar compounds respectively (Khoddami et al., 2013; Uwineza & Waśkiewicz, 2020). The choice of extraction method is influenced by the nature of the bioactive compound of interest and the plant matrix (Izza et al., 2022). Furthermore, the application of non-thermal pre-treatment techniques can enhance the extraction of bioactive compounds (Khoddami et al., 2013).
In summary, the extraction of phenolic compounds from plant materials can be optimized by selecting appropriate extraction techniques, such as MAE or supercritical CO2 extraction, depending on the polarity of the compounds and the plant matrix. These methods offer improved efficiency and sustainability compared to traditional extraction methods, and their optimization is crucial for maximizing the yield of bioactive compounds (Izza et al., 2022; Khoddami et al., 2013; Oman et al., 2013; Quintana et al., 2021; Tanase et al., 2019; Uwineza & Waśkiewicz, 2020).

Source Papers

A Critical Review of Phenolic Compounds Extracted from the Bark of Woody Vascular Plants and Their Potential Biological Activity.

Polyphenols are one of the largest and most widespread groups of secondary metabolites in the plants world. These compounds are of particular interest due to their occurrence and the properties they possess. The main sources of phenolic compounds are fruits and vegetables, but lately, more and more studies refer to woody vascular plants, especially to bark, as an important source of phenolic compounds with a potential biological effect. This study aims to bring together information on the phenolic compounds present in the bark of woody vascular plants by discussing extraction methods, the chemical composition of the extracts and potential biological effects. The literature data used in this paper were collected via PubMed (2004–2019). Search terms were: bark, rhytidome, woody vascular plant, polyphenols, phenolic compounds, biologic activity, antioxidant, immunostimulatory, antimutagenic, antibacterial, anti-inflammatory, and antitumoral. This paper intends to highlight the fact that the polyphenolic extracts obtained from the bark of woody vascular plants represent sources of bioactive compounds with antioxidant, immunostimulatory, antimutagenic, antibacterial properties, etc. Future research directions should be directed towards identification and isolation of bioactive compounds. Consequently, biologically active compounds obtained from the bark of woody plants could be exploited on an industrial scale.

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Open Access
Extraction of Phenolic Compounds from Coleus amboinicus Leaves by Microwave-assisted Extraction: Optimization of the Operating Condition

Torbangun (Coleus amboinicus L) leaf is one of the herbs from Indonesia that has been reported to have many bioactive compounds for human health. These phytochemicals are predominantly incorporated into phenolics, such as flavonoids. An extraction process is needed to obtain all the valuable compounds, and conventional solvent extraction, such as heating and maceration, could be easily applied because of its simplicity. However, this method requires high energy, a longer extraction time, and a large amount of solvent. To overcome these limitations, in this study, microwave-assisted extraction (MAE) was utilized to extract phenolic compounds, including flavonoids from torbangun leaves. Three factors (solvent to feed ratio, microwave power, and extraction time) were evaluated to affect the three responses (extract volume, TPC, and TFC). The extraction process optimization was carried out to get a higher response. The Box-Behnken experiment design and Response Surface Methodology (RSM) determined the optimal operating condition. The result shows 30 ml/g of solvent to feed ratio, 300 W of microwave power, and 4.6 minutes of extraction time as the optimum condition. Applying those conditions, the extract is expected to reach 10.13 ml of extract volume, 9.17 mg GAE/ ml extract of total phenolic, and 3.62 mg QE/ ml extract of total flavonoid. In sum, MAE was useful for extracting phenolic compounds from torbangun leaves and could be an alternative method due to its high efficiency.

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Open Access
Extraction and characterization of bioactive compounds in Vernonia amygdalina leaf ethanolic extract comparing Soxhlet and microwave-assisted extraction techniques

The bioactive compounds in Vernonia amygdalina leaf were extracted using ethanol through Soxhlet and microwave-assisted extraction (MAE) techniques. The phytochemical analysis was carried out on the ethanolic extracts using the standard techniques. This analysis revealed the presence of flavonoids, alkaloids, steroids, terpenoids, glycosides, tannins, phenols, saponins, and the absence of anthraquinones. Furthermore, gas chromatography-mass spectroscopy (GC-MS) analysis results revealed the presence of more phytochemicals in the extract obtained through MAE compared to Soxhlet extraction technique, whereby phytol was present in a higher percentage. Fourier transform infrared spectroscopy analysis confirmed the presence of phytochemicals in the extracts. Moreover, the IC50 values of the extracts antioxidant activities were evaluated using DPPH and ABTS assays. There exists a clear correlation between total phenolic content, total flavonoid content and antioxidant activity of the extracts. Therefore, this study suggested that higher phenolic compounds responsible for natural antioxidant could be obtained from V. amygdalina leaf using the microwave-assisted extraction technique.

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Open Access
EXPLORING APPROACHES FOR INVESTIGATING PHYTOCHEMISTRY: METHODS AND TECHNIQUES

The extraction, isolation, and analysis of bioactive compounds from plants are fundamental in the study of medicinal plants. This review explores various techniques and methods used for the extraction, isolation, and analysis of bioactive compounds from plant materials. Traditional methods such as maceration, percolation, and Soxhlet extraction are commonly used, but novel techniques have emerged to enhance efficiency and selectivity. Microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE), pressurized liquid extraction (PLE), supercritical fluid extraction (SFE), and enzyme-assisted extraction are modern approaches that offer improved yields and efficiency. After extraction, bioactive compounds need to be characterized and analyzed. Chromatographic techniques, such as high-performance liquid chromatography (HPLC) and gas chromatography (GC), are commonly employed for separation and quantification. Spectroscopic techniques, including nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS), provide valuable structural information. The continuous development of extraction and analytical techniques contributes to the discovery and utilization of bioactive compounds from plants in various applications. Future research can explore metabolomics, high-throughput screening, chemoinformatics, network pharmacology, multivariate data analysis, and computational modeling to enhance phytochemical investigations. The proposed methods and techniques complement traditional approaches, expanding our understanding of plant chemistry and its potential applications.

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Open Access