**6.2 Solvent extraction**

This method consists in bringing the plant material into contact with the appropriate solvent; this protocol is carried out cold or hot. Among the most used solvents for the extraction of natural products from plant elements: petroleum ether, methanol, ethanol, and hexane. ne of the glassware used for this extraction technique is soxhlet (**Figure 11**).

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*Plants' Bioactive Metabolites and Extraction Methods DOI: http://dx.doi.org/10.5772/intechopen.96698*

**6.3 Enzyme assisted extraction**

**Figure 11.** *Soxhlet.*

*6.3.1 Plant cell walls*

Enzyme Assisted Extraction is an extraction technique that consists of the destruction of the source material cell wall using specific enzymes to liberate bioactive compounds [25]. Not only does this method augment the extraction yield compared to other conventional techniques, but it also is considered environmen-

The most used enzymes are cellulases, hemicellulases, pectinases, and other hydrolytic enzymes [27]. These have the potential of catalyzing the hydrolysis of plant cell wall components such as polysaccharides and proteins. **Table 1** shows some of the useful plants metabolites and enzymes used for their extraction [26].

Due to their high insolubility and complex structure, plant cell walls are the major barrier to extracting bioactive compounds. Cellulose, the main component of cell walls, is a carbohydrate polymer that is characterized by low solubility and hydrogen- bonded crystalline fibers, which render its degradation greatly arduous. Components of the cell wall intervene in the process of extraction. Therefore, the nature of the cell wall matrix, the nature of the desired compounds, and their

Enzymatic assisted extraction is mainly based on the selectivity and ability of enzymes to intrude the matrix of the cell wall through interaction with the cell wall complex components. Thus, the release of bio-actives in the bulk solution is

tally friendly as it does not require the use of toxic solvents [26, 27].

location are key factors controlling the extraction yield [25].

*6.3.2 Principle and mechanism of action*

**Figure 10.** *Installation of Hydrodistillation.*

*Plants' Bioactive Metabolites and Extraction Methods DOI: http://dx.doi.org/10.5772/intechopen.96698*

**Figure 11.** *Soxhlet.*

*Bioactive Compounds - Biosynthesis, Characterization and Applications*

Phenolic compounds hold a variety of potential therapeutic properties ranging from antioxidant activity, anticancer [22], bacteriostatic, liver-protecting, antiinfection, cholesterol-lowering, immunity enhancement properties [23], cardioprotective and vasodilatory influences [20]. They have increasingly been part of the human diet for centuries for their benefits through the consumption of fruits and

Phenolics stand of great importance to plants. Not only are they responsible for the protection of the plants against exterior hazards [20], but they are also crucial to physiology and cellular metabolism. They play a key role in sensorial traits such as the plants' color and aroma, germination of seeds and

Hydrodistillation is a simple extraction technique which consists in putting in a flask proportional quantity of distilled water and the plant, then heating until boiling;

This method consists in bringing the plant material into contact with the appropriate solvent; this protocol is carried out cold or hot. Among the most used solvents for the extraction of natural products from plant elements: petroleum ether, methanol, ethanol, and hexane. ne of the glassware used for this extraction

the rising vapor condenses using a refrigerant to recover the distillate.

**5.3 Therapeutic usefulness**

vegetables [21, 24].

**5.4 Role for plants**

reproduction [21].

**6. Extraction methods**

*6.1.1 Principle of the method*

**6.1 Hydrodistillation**

*6.1.2 Mounting*

See **Figure 10**.

**6.2 Solvent extraction**

technique is soxhlet (**Figure 11**).

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**Figure 10.**

*Installation of Hydrodistillation.*

#### **6.3 Enzyme assisted extraction**

Enzyme Assisted Extraction is an extraction technique that consists of the destruction of the source material cell wall using specific enzymes to liberate bioactive compounds [25]. Not only does this method augment the extraction yield compared to other conventional techniques, but it also is considered environmentally friendly as it does not require the use of toxic solvents [26, 27].

The most used enzymes are cellulases, hemicellulases, pectinases, and other hydrolytic enzymes [27]. These have the potential of catalyzing the hydrolysis of plant cell wall components such as polysaccharides and proteins. **Table 1** shows some of the useful plants metabolites and enzymes used for their extraction [26].

#### *6.3.1 Plant cell walls*

Due to their high insolubility and complex structure, plant cell walls are the major barrier to extracting bioactive compounds. Cellulose, the main component of cell walls, is a carbohydrate polymer that is characterized by low solubility and hydrogen- bonded crystalline fibers, which render its degradation greatly arduous. Components of the cell wall intervene in the process of extraction. Therefore, the nature of the cell wall matrix, the nature of the desired compounds, and their location are key factors controlling the extraction yield [25].

#### *6.3.2 Principle and mechanism of action*

Enzymatic assisted extraction is mainly based on the selectivity and ability of enzymes to intrude the matrix of the cell wall through interaction with the cell wall complex components. Thus, the release of bio-actives in the bulk solution is


#### **Table 1.**

*List of bioactive compounds of industrial importance obtained by enzyme- assisted extraction from plants [26].*

enhanced. Enzymes bind to their specific substrates by conformational complementarity forming the enzyme-substrate complex and therefore, allowing the hydrolysis to occur. This process is a function of various parameters such as temperature,

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**Table 2.**

*Plants' Bioactive Metabolites and Extraction Methods DOI: http://dx.doi.org/10.5772/intechopen.96698*

enzymes and optimizing related parameters [27].

solvents nor does it harm the environment [26–28].

*6.3.3 Optimum operating conditions*

chosen (**Table 2**) [27].

release of bio-actives.

*6.3.4 Advantages of EAE*

**6.4 Steam distillation**

α-Amylase and glucoamylase

Cellulase, papain, and pectinase

Cellulase, pectinase, and protease

Pectinase and cellulase

Lipase and phospholipase

trypsin

Papain, protease, and

Alginate lyase Fucoxanthin and

lipids

*Different enzymes and their optimum operating conditions [27].*

α-Amylase Polysaccharides *Panax ginseng* —

hydrogen potential, enzyme concentration, the particle size of the substrate, and time of extraction that directly influence the efficiency of EAE. Optimizing these factors implies ensuring a high yield extraction in terms of quality and quantity [25].

The choice of enzymes is the first parameter to study. It is dependent on the chemical structure of the targeted compounds, the structural complexity of the cell wall, and the nature of the raw material. A combination of different enzymes is possible. Optimum temperature and pH are then selected based on the enzymes

Particle size is also a determinant parameter. Small particles were observed to have a better contact between enzymes and substrate and thus lead to a better

A prior understanding of the composition of the raw material, the structure of the cell wall, and the nature of the destinated compounds are necessary for the determination of the optimum operating conditions as it facilitates the selection of

Enzyme Aided Extraction is an advantageous technique and has served as an objective for countless recent studies as it remarkably improves the extraction yield, does not alternate the bio-actives properties, and selectively removes the unwanted components of raw material. Moreover, it does not require the use of toxic organic

Steam distillation is practically the oldest and most famous way of essential oils' extraction [29]. Steam distillation is a separation process for temperature sensitive

**Enzyme used Bioactive extracted Source material Conditions used** Cellulase Polysaccharides Garlic Temperature 45 °C,

Oleoresin Turmeric —

Carotenoids Tomato waste —

Polysaccharides Alfalfa Temperature 52.7 °C,

Seed oil Pumpkin Temperature 44 °C, time

Proteins Olive pulp and stone Temperature 30–40 °C,

Fatty acids *Strongylocentrotus nudus* Temperature 40–55 °C,

pH 5.0, time 80 min

pH 3.87, time 2.73 h

pH 7.0, time 15 min

pH 7.8–8.5, time 180 min

66 min

pH 6.2

*Undaria pinnatifida* Temperature 37 °C,

hydrogen potential, enzyme concentration, the particle size of the substrate, and time of extraction that directly influence the efficiency of EAE. Optimizing these factors implies ensuring a high yield extraction in terms of quality and quantity [25].
