Добавил:

Sekretar kiopkiopkiop18@yandex.ru t.me/Prokururor I Вовсе не секретарь, но почту проверяю Опубликованный материал нарушает ваши авторские права? Сообщите нам.

Вуз:

Ростовский Государственный Медицинский Университет

Предмет:

Медицина общая

Файл:

Книга_5850_Библиотеки_им_академика_М_И_Перельмана

.pdf

Скачиваний:

Добавлен:

30.08.2026

Размер:

49 Мб

Скачать

☆

<<< < Предыдущая 1 2 3 4 5 67 / 507 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 > Следующая >>>

https://t.me/medicina_free

J. Tchamgoue et al.

Fig. 5 Pictures of selected plants used in the treatment of hypertension

Table 5 Antihypertension, chemical constituents, and mechanisms of action of selected medicinal plants

Plant species Chemical constituents Biological activities Mechanism of actions References Allium cepa

(Amaryllidaceae) Apium graveolens

(Apiaceae) Olea europaea

(Oleaceae) Ocimum gratissimum

(Lamiaceae) Terminalia superba

(Combretaceae)

products for the treatment of obesity [116]. Growing research efforts demonstrate the ability of plants and their chemical constituents in preventing and managing obesity, in synergy or individually [117]. Formulations for obesity management have been developed using secondary metabolites such as avonoids, polyphenols, saponins, and alkaloids derived from different plants around the world [117]. In this section, plants frequently used in treating and managing obesity will be presented.

Sulfur compounds, avonoids, and saponins

Monoterpenes Hypotensive Lower systolic and diastolic blood

Polyphenols and avonoids Phenolic compounds,

Polyphenolic acids and avonoids

Tannins, avonoids, saponins, and free anthracene derivatives

Antihypertension and hypotensive

coumarins, triterpenes Antihypertensive Reduces blood pressure in DOCA

Antihypertensive Prevents the increase in blood

Inhibitory action on platelet aggregation

pressure Antihypertensive and

anti-atherosclerotic

salt-conscious hypertensive rats

pressure

lesterol, serum triglycerides, glucose, hepatic lipid accumulation, low-density lipoprotein, adipocyte vacuolization, free fatty acids, and body weight as a result of treatment with S. miltiorrhiza. The observed results were related with elevated levels of lipid factors like hormone-sensitive lipase, cyclic adenosine monophosphate, and protein kinase A in both adipose tissue and liver, and the improvement of lipid metabolism and intestinal integrity [118]. The chemical exploration of S. miltiorrhiza revealed phenolic acids and their deriva-

[102,103]

[104–107]

[109]

[110–112]

[113,114]

tives to be its main constituents. More specically, the fol-

2.6.1 Salvia miltiorrhiza (Lamiaceae)

Salvia miltiorrhiza (popularly called Sal) extract, a common herbal medicine has been shown to be active against obesity, hyperlipidemia, atherosclerosis, and dyslipidemia associated diseases [118]. A report highlighted a decrease in total cho-

lowing compounds caffeic acid, protocatechuic acid, salvianolic acid A&B, protocatechuic aldehyde, ferulic acid, rosmarinic acid, isoferulic acid, przewalskin, cryptotanshinone, dihydrotanshinone I, and tanshinone I and IIA were identied in S. miltiorrhiza extracts [119].

Extraction ofPhytoconstituents forLifestyle Diseases

https://t.me/medicina_free

2.6.2 Ficus carica (Moraceae)

Ficus carica originates from Mediterranean and western Asia where it was cultivated since antiquity. Nowadays, it is extensively grown worldwide as a fruit and ornamental plant. F. carica has already shown antioxidant, antidiabetic, and antiobesity effects invitro (due to its anti-lipase capacity) [120]. Another study highlighted a reduction in animal weight, locomotion, triglycerides, fat body weight (uterine fat, kidney fat, and mesenteric fat), LDL and VLDL levels, cholesterol, and greater HDL levels [121]. Phytochemical studies of the plant have revealed the presence of phenolic compounds and avonoids, steroids, ceramides, pentacyclic triterpenes, and cerebrosides. In addition, the investigation of the most active fraction of F. carica by means of advanced analytical meth- ods including LC-MS and NMR demonstrated that the fraction was rich in oligosaccharides and contained large amounts of oligomeric α-glucopyranosides [122].

2.6.3 Hoodia gordonii (Apocynaceae)

Hoodia gordonii is eaten worldwide for appetite suppression and its subsequent weight loss effects have already been documented. A study found that rats supplemented with H.Gordonii lost weight, which could be attributed to reduced adipocyte size and skeletal muscle ber size [123]. Steroid glycosides are abundant in H. gordonii and hoodigoside L was found to be the major constituent of its organic extract [124]. However, 12-tigloyloxy-14-hydroxypregn5-en-20-one was identied as the constituent responsible for its appetite suppressant property [125].

2.6.4 Moringa stenopetala (Moringaceae)

Popularly called “African moringa” or “cabbage tree,” Moringa stenopetala is a plant native to Kenya and Ethiopia. It is among the most domesticated edible plant with numerous nutritional and medicinal assets [126]. The extract of its seed oil was reported to considerably ameliorate resistin and leptin reduction, as well as metabolic disturbances and HFDinduced hematologic. These effects were exerted through antioxidant enzymes promotion, inammatory cytokines, and lipid peroxidation reduction and iNOS protein expression [127]. Chemical composition revealed the occurrence of carbohydrates, phenols and avonoids, alkaloids, saponins in M. stenopetala leaf powder [128].

2.6.5 Origanum vulgare (Lamiaceae)

Origanum vulgare, also known as wild marjoram, is a typical North American edible and medicinal plant [129]. A metabolite of an 80% ethanolic extract of O. vulgare prevents lipid droplet accretion in differentiating his 3T3-L1 preadipocytes in a concentration-dependent manner [130]. Moreover, the relative mRNA and protein expression levels of c/ebpα, pparγ,srebp-1c, and fas, associated with adipogenesis were lower in the O. vulgare group. Over hundred non-volatile

and volatile compounds were identied in the oil and extracts of this plant with rosmarinic acid being the major phenolic acid [130] (Fig.6 and Table6).

3 Extraction Techniques

ofPhytoconstituents Involved intheManagement ofLifestyle Diseases

3.1 Overview ofExtraction Techniques

Medicinal plants produce various categories of bioactive natural products with different functional groups and polarities. The most important classes of bioactive compounds obtained after extraction from plant are terpenoids, alkaloids, and phenolics [131]. Extraction is a technique used pharmaceutically to separate bioactive parts of plant materials from the bioinactive or inert constituents by means ofsuitable solvents through usual procedures [132]. Several extraction processes are employed for the extraction of bioactive constituents in plants, namely distillation method (for volatile components), sublimation, pressing, and solvent extraction. The latter being the most utilized method for the separation of plant soluble natural products from the insoluble cellular marc [133, 134]. Several studies have reported that the extraction efciency was affected by the plant materials size, its properties, the solvent’s ratio in the raw constituents, temperature, and time of extraction. Increasing time lead to rise in the percentage and efcacy of extraction. In this method, the solubility, selectivity, safety, and cost of the solvent play an important role. Therefore, natural products with the same polarity as the solvents will lead to a greater extraction percentage. The solubility and stability of bioactive compounds are affected by a high temperature, which can result to the degradation of thermo-labile bioactive components in the solvents [135]. The extraction processes of plants natural products using solvents comprise infusion, maceration, soxhlet extraction, decoction, percolation, microwave and ultrasound-assisted extractions, supercritical uid extraction, enzyme-assisted extraction, and pressurized liquid extraction [133, 134].

3.1.1 Maceration

In this method, the powdered plant raw material is soaked with a solvent at room temperature for 72h and is shaken frequently to facilitate dissolution of the soluble matter. The mixture is then ltered and the solvent evaporated to afford the crude plant extract [135, 136].

3.1.2 Infusion

Infusion is an adequate method for the extraction of plants rich in volatile constituents or that easily release their bioactive

https://t.me/medicina_free

J. Tchamgoue et al.

Fig. 6 Pictures of selected plants used in the treatment of obesity

Table 6 Anti-obesity, chemical constituents, and mechanisms of action of selected medicinal plants

Biological

Plant species Chemical constituents Salvia miltiorrhiza

(Lamiaceae)

Ficus carica (Moraceae)

Hoodia gordonii (Apocynaceae)

Moringa stenopetala

(Moringaceae) Origanum vulgare

(Lamiaceae)

Phenolic acids and derivatives Anti-

Phenolic compounds and avonoids, steroids, ceramides, pentacyclic triterpenes, and cerebrosides

Steroidal glycosides Anti-

Carbohydrates, avonoids, phenols, alkaloids, saponins

Phenolic acid derivatives Anti-

compounds in solvents (berries, dried owers or herbs). The liquid is usually brought to another suitable temperature and then poured onto the plant material, which is then left to soak in the solvent for some time. Claried solvents are obtained by

activities Mechanism of actions References

Elevate levels of lipid factors including HSL, cAMP, and

obesity

Antiobesity

obesity Anti-

obesity

PKAin adipose tissue Ameliorate lipid metabolism and gut integrity

Anti-lipase, decrease in triglycerides, LDL, cholesterol, and VLDL levels. Increase in HDL levels

Reduce adipocyte size and skeletal muscle ber size was shown

Promotes antioxidant enzymes Reduces lipid peroxidation, inammatory cytokines, and iNOS protein expression

Inhibits lipid droplet accumulation in differentiating 3T3-L1 preadipocytes and reduces the relative expression levels of pparγ, c/ebpα, fas, and srebp-1c mRNAs and proteins associated with adipogenesis

extracted. Usually, infusion should be done for less than 30min or until the liquid cools. The volume of the solvent depends on the quantity of the raw plant materials and required

concentration of the resulting infusion [135, 137]. ltration or the marc is simply retrieved from the liquid. The length of time plant materials are left in the solvent depends on the reason for which the infusion is prepared. The choice of the solvent depends on the nature of the compound to be

3.1.3 Percolation

This extraction method involves soaking for about 4h the

raw material in a closed container with the required amount

[118,

119]

[120–122]

[124,

125]

[126–128]

[129,

130]

Extraction ofPhytoconstituents forLifestyle Diseases

https://t.me/medicina_free

of solvent. Due to an additional solvent which is poured on the raw materials, the maceration is left for 24h in the closed container. The dripwise extract is poured out using an opening percolator. Additional solvent is added until the percolate is approximately three quarters of the required amount of the nal product. The marc is squeezed and the resulting solvent is appended to the percolate. The required volume is produced using additional solvent and the ltration or decantation affordsa mixed claried liquid [134, 137].

3.1.4 Decoction

The bioactive no thermo-labile (no heat stable) natural products can be extracted using decoction method. This method is frequently used for the preparation of herbal drugs in traditional medicine. The process involves boiling for about 15min to up to an hour the plant material depending on the plant’s part and its bioactive constituents. The desired volume is obtained after cooling, straining, and addition of enough cold solvent through plant materials. Therefore, the leaves, roots, stems, and owers are boiled for approx. 15min, while other hard parts such as branches require a longer boiling time during which the evaporated solvent must be replaced [134].

3.1.5 Soxhlet Extraction or Hot Continuous

Extraction

In this process, a powdered sample to be extracted is placed in a porous cartridge made of solid lter paper or cellulose and located in a chamber of the Soxhlet apparatus. The bottom ask is used to heat organic solvents to reux and are evaporated in the sample cartridge. After condensation, the runoff results in the extraction of biological active constituents from the plant [135, 136, 138].

can be completed in minutes with higher extraction rates,

streamlined processing, high capacity for the nal product,

while reduced input of solvent and post-extraction waste-

water treatment disposal. It uses of fossil energy is reduced

as compared to commonly used methods such as soxhlet,

maceration, and distillation[139, 140]. The advantage of

this method is that it signicantly increases the solvent

extraction of natural products from plants. In addition, the

duration of the process is reduced and higher extraction

yield and quality were obtained using UAE [139]. The

extraction of bioactive components depends on the nature

of the solvent, agitation, and heat. This method is suitable

for extracting bioactive secondary metabolites from spices

and herbs, proteins, and oil from soy and seeds, respec-

tively [139, 141].

3.1.8 Supercritical Fluid Extraction (SFE)

This technique allows the extraction of targeted compounds

using supercritical carbon dioxide as a solvent at high pres-

sure and temperature above its critical values (7380kPa and

31.1°C) [134, 139]. The undesired materials can be removed

from the product using this method [137]. Using supercriti-

cal uid provides this method with numerous advantages

compared to conventional techniques because, these solvents

possess diverse physico-chemical assets including viscosity,

dielectric constant, density, and diffusivity. Supercritical

CO2 diffuses easily through solid matrices and has low vis-

cosity, high diffusivity, and enhanced transport abilities that

greatly increase its extraction rates [142]. Supercritical uid

possesses low solubility for polar natural products. This

problem of solubility of polar compounds can be solved by

adding methanol or ethanol. In addition, CO2 has low toxic-

ity, is cheap and available [141].

3.1.6 Microwave-Assisted Extraction (MAE)

The partition of analytes from the sample matrix into the solvent are facilitated in this method by the use of microwave energy. Microwave radiation with a frequency of 300MHz to 300GHz and a wavelength of 1mm to 1m acts directly on polarizable and polar materials such as solvent. A resulting plant sample is heated near the surface of the materials and conduction is used to transfer the heat. This method is used for the extraction different bioactive natural products from plant materials. It is a very rapid and cost-effective method as compared to other common methods [137].

3.1.7 Ultrasound-Assisted Extraction (UAE) or

Sonication Extraction

UAE is known as a green extraction technique for plants secondary metabolites. Its waves frequency range from 20 to 2000kHz [135, 139]. A green extraction technique of bioactive secondary metabolites is known as UAE.A complete extraction of bioactive natural products using UAE

3.1.9 Enzyme-Assisted Extraction (EAE)

It is an enzymatic process where a specic hydrolyzing

enzyme, namely α-amylase, pectinase, or cellulase, is

added during the extraction step [143]. In some plants,

hydrogen or hydrophobic bonding is used to retain natural

products in the polysaccharide-lignin network. Thus, a sol-

vent extraction process is not accessible to secondary

metabolites. In order to effectively free the bounded natural

products and improve their total yield, an enzyme pretreat-

ment is necessary [131]. It is a novel and effective method

for the extraction of antioxidant natural products from nat-

ural resources [144]. The temperature, time of extraction,

system’s pH, concentration of the enzyme, and the size of

substrate particles are numerous parameters for the effec-

tiveness of the extraction process. Nevertheless, the bioac-

tive compounds were reported to be extracted from plant

materials by means of a mixture of cellulolytic enzymes

and pectinolytic (1:2 ratio), at 40°C, 4.0 pH, and for 2h

treatment [136, 145].

https://t.me/medicina_free

J. Tchamgoue et al.

3.1.10 Pressurized Liquid Extraction (PLE)

The effective extraction of targeted compounds in this method requires using high pressure (2–20MPa) and temperature (up to 200°C) liquid solvent. The high solvent penetration into the matrix is due to the high diffusion and solubility rates of hydrophobic compounds into the solvent, which reduces solvent requirements and extraction time. Several research teams have described PLE as accelerated solvent or uid extraction, “high-pressure solvent extraction (HSPE),” and “enhanced solvent extraction (ESE).” By comparison to the conventional soxhlet extraction, this method considerably decreases solvent and time consumption. It is a potential substitute to SFE [134, 136, 139, 146] (Table7 and Scheme 1).

3.2 Specic Procedures forExtracting

Some Classes ofCompounds Involved intheManagement ofLSD

Several medicinal plants were reported to possess benecial effects on lifestyle diseases. Their chemical and biological investigation have provided numerous compounds which have ascertain the claim pharmacological properties of these plants. As highlighted in the previous sections, these compounds belong to various classes of compounds including phenolics, alkaloids, and terpenoids. This section will focus on specic techniques for extracting these classes of compounds.

3.2.1 Extraction ofPhenolic Compounds

This class of secondary metabolites represents one of the largest group of compounds found in plants. They have in

common benzene ring substituted by one or more hydroxyl

groups. Based on their basic structures, they can be divided

in two main classes, namely avonoids and non-avonoids.

The specic substituent in the basic structure gave rise to

phenolic subclasses. Non-avonoid phenolic compounds are

divided into the following subgroups based on their carbon

skeleton: coumarins, tannins, etc. [145].

3.2.1.1 Flavonoids

The general basic skeleton of avonoids consists of 15 car-

bons grouped into two benzene rings (A and B) linked by

three linear carbons (C6-C3-C6) which could bridge with an

oxygenated heterocycle to give a third ring (C) [148, 149].

Their classication is based on changes observed in C-ring

heterocyclic structure and over 7000 avonoids have been

identied from natural sources [150]. Due to their interesting

biological properties, the number of identied avonoids

keeps on rising. Based on their structure (which differs from

the central structure of the avans by the central motif of the

heterocyclic pyran ring), they are allocated in seven sub-

classes including anthocyanins, avones, isoavones, avo-

nols, avanonols, avan-3-ols, and avanones [148, 149].

Flavonoids could exist in free state but are often prenylated,

methylated, acetylated, or glycosylated. In addition, several

polyavonoids have been identied [151]. The extraction

and recovery of avonoids has increased in recent years due

to demographic trends toward better lifestyles and the

inclusion of antioxidants in LSD management. Thus numer-

ous avonoid extraction techniques have been implemented

to improve yield of extractions and reduce processing costs

of these important bioactive natural products [148, 149].

Various extraction methods have been implemented, includ-

ing infusion, decoction, maceration, percolation, steeping,

Table 7 Extraction methods of natural products [135]

Required

Methods Solvents Pressure Temperature Time Maceration Water, aqueous and

non-aqueous solvents Decoction Water Atmospheric Under heat Moderate None Polar compounds Soxhlet extraction Organic solvents Atmospheric Under heat Long Moderate Dependent on

Percolation Water, aqueous and

non-aqueous solvents Pressurized liquid

extraction Microwave-assisted

extraction Ultrasound-assisted

extraction Supercritical uid

extraction

Enzyme-assisted extraction

Water, aqueous and

non-aqueous solvents

Water, aqueous and

non-aqueous solvents

Water, aqueous and

non-aqueous solvents

Water, aqueous and

non-aqueous solvents

Atmospheric Ambient temperature Long Large Depend on

Atmospheric Ambient temperature,

occasional heat

High Under heat Short Small Dependent on

Atmospheric Ambient temperature Short Moderate Dependent on

Atmospheric Ambient temperature or under

heat

High Near ambient temperatures Short None or

Atmospheric Ambient temperature or

heated after enzyme treatment

Long Large Dependent on

Short Moderate Dependent on

Moderate Moderate Dependent on

volume Compounds polarity

extracting solvent

extracting solvent Non-polar to

small

moderate compounds

extracting solvent

Extraction ofPhytoconstituents forLifestyle Diseases

https://t.me/medicina_free

Selection of plant species:

 Preliminary screening of traditionally used plants  Literature review and scientific result  Authentication of data for their validity and comprehensiveness  Decision regarding the necessity of testing

Biological activity:

 Selection of suitable biological test  Develop protocol for biological test  Analyze biological activity in vitro  Determine level and type of biological activity

Isolating bioactive secondary metabolites:

 Isolation and characterization of bioactive natural products  Evaluation of bioactive compounds singulary and in

combination with others to explore existence of activity and / or synergy of biological effect

Evaluation of toxicity:

 Gather data concerning toxicity and if demonstrate no toxicity

then proceed to next step

 If toxicity data is absent, select an appropriate test for toxicity

analysis

 Develop and prepare bioassay protocol for safety and toxicity

Preparation of plant sample and elemental analysis:

 Collection of plant materials  Extraction

 Use various extraction methods  Compare the selectivity and yield

 Analysis for elemental components

In vivo analysis:

 Use animal model for bioactivity analysis of

bioactive natural products

 Analyse again safety and toxicity but in vivo  Conduct humane studies

Commercialization:

 Develop appropriate dose delivery system  Analyse cost effectiveness  Sustainable industrial production

Scheme 1 The ow chart of medicinal plant study and position of extraction techniques [147]

and soxhlet. The latter is most often used and suitable technique for the extraction of avonoids owing to its low solvent content, easiness, low cost, and ease of maintenance. The type of avonoids extracted is inuenced by the nature of the extraction solvent which affects the bioactivity of the obtained compounds. Thus, different solvents including ethanol, methanol, ethyl acetate, chloroform, petroleum ether, etc. were assessed for their avonoid extraction potential and it resulted that ethanol and methanol are the most suitable solvents for the extraction of this class of compounds. Moreover, liquid–liquid and solid–liquid extractions are the most used techniques for extracting avonoids [150]. Extraction methods involving heat might result in the denaturation of avonoids and thus to an observed decrease in their bioactivity [148–150] (Schemes 2 and 3).

metabolites attractive for further skeletal derivatization and screening as new therapeutics [153, 156]. Scientists have reported several methods for extracting coumarins and their glycosides. Extraction with high polarity solvents such as methanol, ethanol, and water have been proven to be more efcient. Greater amounts of free coumarins are obtained when water extraction is done at ambient temperature rather than at 100°C.Extractions of courmarins and their glycosides with medium and low polarity solvents such as diethyl ether, EtOAc, and CHCl3 are very poor. Regarding furanocoumarins, the best extraction is achieved with solvent reux or soxhlet extraction techniques using boiling methanol as solvent. Similar results were obtained with H2O, CHCl3 at room temperature, EtOAc, and MeOH.The lower extraction yield of furanocoumarins was obtained with diethyl ether while the extraction with water gave similar results with

3.2.1.2 Coumarins

Coumarins are natural phenolic products found in specic

methanol, making the latter a very interesting solvent for the

extraction of furanocoumarins [154, 156]. plants families and genus. It comprises a benzene ringbonded to a lactone ring. They are derivatives of 1,2-benzopyrone and known for their pleasant vanilla odor [153–156]. There are four principal subclasses of coumarins, namely simple coumarins, pyranocoumarins, furanocoumarins, and pyronesubstituted coumarins. They can be alkoxylated, glycosylated, hydroxylated, and alkylated. They attract great attention owing to their pharmaceutical assets, physiological, antitumor, and bacteriostatic activity which makes these secondary

3.2.1.3 Tannins

Tannins are phenolic compounds with high molecular weight

and numerous hydroxyl groups. More than 8000 different

tannins have been reported. In plant cells with molecular

weights of up to 500Da, they exist in free and bound forms.

They have very diverse and different chemical structures.

Phenolic acids such as gallic and ellagic acids can be obtained

after hydrolysis of some tannins. Tannins are normally

https://t.me/medicina_free

J. Tchamgoue et al.

Scheme 2 Extraction ow chart of Flavonoids [136]

Step 1: what are the goals of the conducted research?

Medicinal use or food supplements

Standard and validationextraction procedure

Plant materials

(medicinal or edible plant species)

Research and development of flavonoid fractions with narrow range of physiological effects

Step 2: selecting a pre-extracting sample preparation

a. Fresh or dried sample b. Grinded or powdered samples

Step 3 : Selecting a solvent

a. Non polar solvent b. Organic solvent mixture c. Alcohol d. Alcohol water mixture e. Water

Identification of extract Ingredients of new plant species

Quantitative extracting procedure using alcoholic solvents

divided into two classes of chemical compounds, namely hydrolyzable and condensed tannins. Chemically, hydrolyzable tannins are heteropolymers composed of polyphenolic acids and their derivatives, esteried to a polyol while condensed tannins are polymeric avonoids [157–159]. Tannin content generally ranges from 0.2 to 25 dry weight and depends different factors including extraction methods. Tannins were reported to possess several bioactivities such as antioxidant, antitumor, etc. which are important in the management of LSD. The number of aromatic rings and hydroxyl radicals greatly inuences the biological potentials of tannins [157, 158].

The valorization of tannin extraction method remains the greatest challenge due to the fact that tannin extraction is not performed in a single process. The extracted tannins generally contain various kinds of impurities such as stilbenes, sugars, and minerals which are due to the extraction process. Processing factors such as size of particles, pressure, temperature, time, the amount of solid and extraction solvent, and the nature of the solvent impact the amount of impuri-

Step 4 : Selecting an extraction technique

a. Maceration b. Soxhlet extraction c. Microwave assisted extraction (MAE) d. Supercritical fluid extraction (SFE) e. Ultrasonic assisted extraction (UAE) f. Pressurized liquid extraction (PLE) g. Enzyme assisted extraction (EAE)

ties. These operational parameters need to be carefully controlled in order to extract tannins. Hot water or water with other solvents are generally utilized for the extraction of tannins from natural sources. Ethanol, methanol, acetone, ethyl acetate, ethyl ether, diisopropyl ether, sodium sulte, and sodium hydroxide have been used as solvents with or without water by various scientists. Based on these studies, methanol extraction gave a better yield compared to water extraction. Yet, due to its simplicity and lower cost, extraction with hot water remains very common and widely employed in industries and laboratories for tannin extraction. The yield of extracted hydrolyzable and condensed tannins was reported to be higher using hot water. The temperature of water depends on the plant material, the extraction technique and the size of particles to be extracted [155].

3.2.2 Extraction ofAlkaloids

Alkaloids are nitrogen-containing alkaline secondary metabolites and are well known for their physiological properties. They mostly originate from plants, particu-

Extraction ofPhytoconstituents forLifestyle Diseases

https://t.me/medicina_free

Scheme 3 Extraction ow chart of polyphenols and tannins [152]

Powdered plant materials

Filtrate of crude extract

2nd Extraction tannin with diethyl ether

Organic fraction

Extraction of polyphenols using H2O/MeOH (1/4) (solid: liquid, 1:20, g/mL)

Methanolevaporation (40 °C)

Addition of two drops of HCl(6N) in the aqueous sample

Extracting phenolic components with diethyl ether

Decantation and separation phase

Aqueous fraction

3rd Extracting tannin with diethyl ether

Organic fraction

Drying sample with anhydrous Na

Evaporation of diethyl ether

Polyphenolic fraction

Aqueous fraction

Sample dry with anhydrou sodium sulfate

2SO4

larly higher plants [160, 161]. Alkaloids rich herbal drugs contain both active and toxic components. The weakly alkaline alkaloids exist in the free form, such as amide alkaloids. Alkaline alkaloids occur mainly as organic salts such as succinate, citrate, oxalate, tartrate, oxalate, etc. Few exist as inorganic salts such as morphine sulfate or berberine. There are other forms of N-oxide alkaloid glycosides [158]. Alkaloidal extracts have extensively been used in pharmaceutical formulations [159]. To improve their therapeutic effects, natural products should be efciently extracted while eliminating the inactive and toxic constituents. In this light, alkaloids extraction has drawn more consideration due to their huge market demand, resulting in an upswing of research work on their extraction procedure [160, 162]. The choice of an extraction process principally depends on the type and occurrence of the alkaloids in plants. Generally, the solvent extraction process is mostly used due to their solubility, which is a signicant basis for extraction. The frequently used technique include alcohol-solvent and acid-water extractions, percolation, soxhlet, lipophilic organic solvent extraction, ultrasound- assisted extraction, microwave extraction, supercritical uid extraction, and enzymatic method, etc. [160, 162] (Scheme 4).

Test sample for determination of

condensed and hydrolysables

3.2.3 Extraction ofTerpenoids

They are an important group of natural products by some plants and animals [163–165]. More than 80,000 types of terpenoids have been discovered to date. Thus, it is known that the structural diversity of terpenoids is responsible of the pharmacological applications of chemicals extracted from plants. Depending on the number of isoprene units, terpenoids are classied as saponins, cardiac glycosides, steroids, etc. [164, 165].

Saponins are natural bioorganic secondary metabolites containing one or more glycosidic bond on carbon C-3 between the aglycone and a sugar chain [166, 167]. The aglycone moiety, also called sapogenin or simply genin, is either a steroid, triterpenoid or an alkaloid [164]. They can be called mono-, di-, or tridesmosidic if one, two, or three sugar chains are linked to the sapogenin [163]. The extraction procedure of saponins from natural sources have been widely studied and this may be due to increased public health awareness. In general, traditional and green technologies are the two categories of extraction techniques used for extracting saponins from medicinal plants [166, 168].

Cardiac glycosides are a group of closely related natural substances with a strong specic and powerful effect on the heart muscle. Their action on the heart is through direct and

https://t.me/medicina_free

J. Tchamgoue et al.

Scheme 4 Extraction ow chart of total alkaloids [160]

Insoluble matter

Powdered plant materials

Crude extract

Aqueous fraction Organic fraction

- Adjust pH = 10 using appropriate base (NH4OH, …)

- Extract with suitable organic solvent (ethyl acetate, chloroform,…)

- Solvent removal

Alkaloid fraction

indirect mechanisms to increase the strength and speed of contraction. In high doses they can be toxic while smaller amounts could have useful stimulation effect on the heart. They have shown effects on myocardial tone, excitability and contractility, and diuretic activity [166]. Medicinal plants extracts rich in cardiac glycosides and their derived formulations were utilized since antiquity as medicines and poisons. The frequently employed method for extracting this class of compound is by protecting the raw plant material beforehand through maceration at 25–37°C in toluene for several days in order to avoid enzymatic hydrolysis. An extensive extraction with a hydro-alcoholic mixture is further done and the resulting extract is evaporated under vacuum at 50°C to a small volume. Fats are further removed by extracting with petroleum ether and aqueous glycoside syrup diluted in an equal volume of water. Acidic products including tannic acid and polyphenols are precipitated with prepared lead hydroxide and the resulting mixture ltered through hyosuper gel. The pH of the ltrate is adjusted to 6 which is further concentrated in vacuo and successively extracted with petroleum ether, CHl3, CHl3/alcohol (2:1) and (3:2) [169, 170].

Steroids are primarily composed of lipophilic compounds with a variety of biological and physical properties. They contain natural polycyclic isopentenoids whose basic 1,2-cyclopentanophenthrene structure is modied on the side chain by the addition of lipophobic or hydrophilic or polar groups. Steroids are essential group of natural products found in most cells and rampant in medicinal plants. Several steroids have also already been synthesized. Regarding their extraction process from natural sources, their polarity and interaction with binding proteins must be considered [171–

173]. The extraction solvent must completely break the bond

between the protein and the steroid and facilitate quantitative

- Appropriate extraction method (maceration, percolation, etc)

- Suitable solvent (methanol, ethanol, etc)

Dissolved in suitable acid solution (HCl, …),with pH = 2.0 and filtered

Filtrate

Partition using non polar organic solvente.g. n-hexane chloroform,…

extraction of the targeted steroids, leaving other steroids and non-desirable substances in the aqueous medium. Practically this is impossible as the solvent will also extract other compounds with analogue polarity which indeed affect the nal yield. In the case of steroids linked to lipoproteins (e.g., vitamin D and cholesterol), the addition of chemical which will break down the lipoproteins prior to extraction might be necessary. Better extraction yields of bile acids and their conjugates linked to proteins are often obtained from alkaline media instead of acidic aqueous media. The extraction of more polar steroids such as sulfate conjugates, glucuronide, and polyhydroxy steroids is sometimes not efcient with very polar solvents [170] (Scheme 5).

3.2.4 Extraction ofOthers Classes ofCompounds

Ceramides are specic bioactive sphingolipid metabolites formed from a fatty acid linked through an amide function to a long-chain amine called a sphingoid. The predominant long sphingoid chain bases in plants are the C18 amino alcohols. Long-chain dihydroxy-sphinganine and long-chain trihydroxy- 4-hydroxysphinganine are found not only as generally minor components of complex sphingolipids, but also as long-chain free bases in plant tissues. Plant ceramides exist primarily in acylated, glycosylated, or polyhydric fatty acid forms and exhibit good biological activity. They have been identied as lipid compounds [174–176]. These amides reside in the cytoplasmic membrane where their role in cells development and growth are vital. Therefore, cancer, some skin diseases, and other dysfunctional cellular diseases can be caused by decreasing their levels. Ceramides and their glycosides are sphingolipids that constitute an important part (about 10%) of higher plant lipids. Thus far about 200 plant lipids have been described and several others are still on their

Extraction ofPhytoconstituents forLifestyle Diseases

https://t.me/medicina_free

Scheme 5 Extraction ow chart of total saponins

n-hexane or petroleum ether fraction

Precipitated saponins fraction

Powdered plant materials

Aqueous fraction

Partition with saturated n-butanol

n-butanol fraction

Addition of acetone or petroleum ether

way. The diversity of their structures eases their role in different cellular processes resulting in their involvement in numerous activities such as the formation of membrane domains, structural integrity of membranes, and plant response to hypoxia and pathogen attack [173]. Besides commonly applied extraction procedures, supercritical uid extraction (SFE) could also be used for extracting ceramides, but this method is very expensive. Thus, techniques such as ultrasonic-assisted extraction and enzyme-assisted extraction have become prominent [172].

Sulfur is an essential plant macronutrient that is a prominent component of amino acids and several metabolites. It also plays a great role in different cellular metabolic processes and is frequently responsible for the structure and biological activity of proteins [174, 175, 177]. Sulfur derive compounds play a vital role in plants life cycle and in their protection against pathogens and environmental stresses [175, 176]. Organo-sulfur compounds and particularly those from Allium species are low molecular weight molecules. These bioactive natural substances can be obtained using conventional or modern extraction methods, however, extraction by hydro-distillation or maceration with ethanol or water at ambient temperature have been proven to be very efcient [177].

4 Conclusion andOutlooks

This chapter has given insights into medicinal and edible plants with benecial properties against lifestyle diseases, their mechanisms of action as well as their phytoconstituents.

- Appropriate extraction method (maceration, percolation, etc)

- Suitable solvent (methanol, ethanol, etc)

Crude extract

- Dissolved in water,

- Partition with n-hexane or petroleum ether

Aqueous fraction

Partition with chloroform or ethyl acetate

Chloroform or ethyl acetate fraction

The most represented classes of compounds of these phytoconstituents were alkaloids, sulfur compounds, phenolic compounds (phenolic acids, avonoids, and tannins), terpenoids, and steroids. The suitable extraction techniques of these phytoconstituents were also discussed. However, more investigations are required to quantify the bioactive components of these plants depending on the extraction method used.

Acknowledgment The authors are grateful to the Alexander von Humboldt Foundation (3.4-CMR-Hub) for the nancial support to the Centre of Competence for the Study of Antimicrobial Natural Products from Fungi (CECANAPROF).

References

1. Kshirsagar MV, Ashturkar MD. Prevalence of lifestyle diseases in Maharashtra: a comparison between NFHS-5 and NFHS-4 surveys. J Family Med Prim Care. 2022;11(6):2474–8.

2. Umereweneza S, Kirkgulhorn T, Seetangkham S. Measures to prevent disease from lifestyle. Int J Health Sci Res. 2018;12(Suppl):20–8.

3. Tabish SA. Lifestyle diseases: consequences, characteristics, causes and control. J Cardiol Curr Res. 2017;9.

4. Module for multi-purpose workers—prevention, screening and control of common NCDS_2.pdf. [cited 2023 Jan 30]. https://

main.mohfw.gov.in/sites/default/files/Module%20for%20 Multi- Purpose%20Workers%20- %20Prevention%2C%20 Screening%20and%20Control%20of%20Common%20NCDS_2. pdf.

5. Plant-based diets and their impact on health, sustainability and the environment: a review of the evidence. [cited 2023 Jan 30]. https://www.who.int/europe/publications/i/item/

WHO- EURO- 2021- 4007- 43766- 61591.

<<< < Предыдущая 1 2 3 4 5 67 / 507 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 > Следующая >>>

Соседние файлы в папке Библиотека им академика М.И. Перельмана

#
30.08.202652 Мб0Книга_5846_Библиотеки_им_академика_М_И_Перельмана.pdf
#
30.08.202652 Мб0Книга_5847_Библиотеки_им_академика_М_И_Перельмана.pdf
#
30.08.202650 Мб0Книга_5848_Библиотеки_им_академика_М_И_Перельмана.pdf
#
30.08.202649 Мб0Книга_5849_Библиотеки_им_академика_М_И_Перельмана.pdf
#
30.08.202675 Мб0Книга_585_Библиотеки_им_академика_М_И_Перельмана.pdf
#
30.08.202649 Мб0Книга_5850_Библиотеки_им_академика_М_И_Перельмана.pdf
#
30.08.202648 Мб0Книга_5851_Библиотеки_им_академика_М_И_Перельмана.pdf
#
30.08.202647 Мб0Книга_5852_Библиотеки_им_академика_М_И_Перельмана.pdf
#
30.08.202646 Мб0Книга_5853_Библиотеки_им_академика_М_И_Перельмана.pdf
#
30.08.202645 Мб0Книга_5854_Библиотеки_им_академика_М_И_Перельмана.pdf
#
30.08.202645 Мб0Книга_5855_Библиотеки_им_академика_М_И_Перельмана.pdf