A comprehensive review of conventional and non-conventional solvent extraction techniques

Abstract

Phytochemicals are produced by plants during primary or secondary metabolic activities. They are the bioactive compounds playing important role in the defense of the host plant against different biotic and abiotic agents and functioning in attraction and stimulation. Most of these phytochemicals are found to be having beneficial effects on the health of human beings. All Indian traditional system of medicine like Ayurveda, Unani, and Siddha uses phytochemicals in their formulations. In the Moderns era, synthetic analogs or prototypes of natural phytochemicals are used which is however not advisable. It is always recommended to extract the phytochemicals from their natural sources scientifically. The bioactive component is recovered from raw materials by dissolving them in appropriate solvents at suitable temperatures. Phytochemicals can be extracted by various techniques; classical as well as modern. The current review attempt to bring out a comparative study of all the conventional and non-conventional techniques used for the extraction of phytochemicals.

Unlocking Therapeutic Potential: Comprehensive Extraction, Profiling, and Pharmacological Evaluation of Bioactive Compounds from Eclipta alba (L.) Hassk. for Dermatological Applications

“…Soxhlet extraction operates based on the principle of continuous solvent reflux, allowing for efficient target compound extraction [ 68 , 69 ]. This method has been used in the bioactive compound extraction process from E. alba , as described in Table 2 .…”

“…Thus, previous findings suggest future research to elucidate the specific factors influencing the extraction process for better understanding of bioactive compounds profile of E. alba plant. [68,69]. This method has been used in the bioactive compound extraction process from E. alba, as described in Table 2.…”

Essential Components from Plant Source Oils: A Review on Extraction, Detection, Identification, and Quantification

“…Different oil extraction techniques from plant sources are being practiced and work differently: cold pressing extraction (CPE) requires mechanical power and does not need organic solvents [38]; supercritical-fluid extraction (SFE) uses a supercritical fluid as a solvent; ultrasound-assisted extraction (UAE) involves ultrasonic waves [39], while microwaveassisted extraction (MAE) uses microwave energy [40], and pulsed electric field (PEF) technology uses short electricity pulses [41]; pressurized liquid extraction (PLE) uses conventional solvents under high temperatures and pressure for extraction in a short time [42]; and enzyme-assisted extraction (EAE) involves enzyme hydrolysis that allows the effective extraction and delivery of bioactive compounds [43].…”

Natural pigments (anthocyanins and chlorophyll) and antioxidants profiling of European red and green gooseberry (Ribes uva-crispa L.) extracted using green techniques (UAE-citric acid-mediated extraction)

“…In some cases, prior to applying the extraction methods, it is important to remove other compounds such as protein, lipids and contaminants from the sample matrix that may obstruct the extraction of anthocyanins and other natural pigments ( Tan et al, 2022 ). Decoction, maceration, soaking, percolation and Soxhlet extraction are some examples of conventional extraction methods, which are currently used in natural dye industries because these extraction methods have low costs of instrumentation and maintenance ( Goti and Dasgupta, 2023 ). However, despite their wide usage, these conventional extraction methods also have some limitations such as high energy consumption, use of harmful and expensive organic solvents, use of huge volumes of solvents, lower yield, use of high temperature and long extraction time, which all can deteriorate antioxidants and other compounds of interest ( Belwal et al, 2018 ).…”