**2. Green extraction**

A vast diversity of plants, animals, and microorganisms can produce a wide spectrum of chemical compounds with amazing health-care properties in nature. Science is steadily changing our world by finding the possibilities of natural products [7]. Natural product extraction has been practised since civilization. Extraction methods are used in the perfume, cosmetics, pharmaceutical, food, and chemicals sectors. Recent extraction technique advancements have mostly focused on creating solutions that employ lower solvents [8].

Soxhlet extraction, maceration, and hydro distillation (HD) are examples of traditional/conventional extraction processes. The choice of specific solvents has a considerable impact on any extraction rate. The polarity of the target biochemical is the most significant factor to consider, and when choosing a solvent, the solvent's molecular affinity for the solute, as well as its environmental friendliness, toxicity, and economic efficiency, must all be considered. Simple, safe, repeatable, low-cost, and adaptable to a variety of applications are all desirable characteristics in an extraction procedure. High-temperature extraction (e.g., Soxhlet technique, HD) has been shown to cause changes in the composition due to phytoconstituent degradation [9].

To circumvent the constraints of classic extraction procedures, green extraction techniques can be employed to extract phytoconstituents from plants. The majority of these include less harmful chemical synthesis, nontoxic chemicals, safe solvent aides, energy efficiency patterns, use of sustainable feedstock, fewer derivatives, catalysis, design to avoid deterioration, and time scheduling for pollution avoidance, hazardous air pollutants, and naturally safer chemistry for safety programs. The development of effective and selective technologies for extracting and isolating bioactive phytoconstituent is crucial. This article aims to provide a detailed overview of green solvents employed, as well as the methods for extracting and isolating natural compounds form natural sources. Green solvents can help to improve old procedures significantly, especially when incorporated with new and novel methodologies. Hydrolysis of cellulose from biomass with supercritical water and the extraction of hydrophobic compounds using supercritical CO2 are few examples of green extraction process.
