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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_6035_Библиотеки_им_академика_М_И_Перельмана.pdf
TABLE 8.1 NPs Obtained from Plants and Their Important Properties
Sr.
Natural
No.
Compound
1. Cannabidiol
2. Colchicine
3. Artemisinin
4. Epigallocatechin3-O-gallate
5. Genistein
6. Masoprocol
7. Podophyllotoxin
8. Quercetin
9. Capsaicin
10. Resveratrol
Botanical Name
(Common Name)
Cannabis sativa L. (Marijuana)
Colchicum spp. (Meadow
saffron)
Artemisia annua L. (Mugwort)
Camellia sinensis L.
(Green tea)
Genista tinctoria L. (Dyer’s
greenweed)
Larrea tridentate (Greasewood)
Podophyllum emodi Wall. And
P. peltatum L. (Devil’s Apple)
Morus alba (White mulberry)
Capsicum annum L. (Bell
pepper)
Vitisv inifera L. (Common grape)
Therapeutic Value Mechanism of Action
Antipsychotic, anticancer, antiepileptic,
and anxiolytic
Used for the treatment of gout Prevents assembly of microtubules which leads to
Used for the treatment of malaria Alkylation of essential malarial proteins by free radical
Antidiabetic, anti-inflammatory,
antifungal, antibacterial, and antiviral
activity against DNA and RNA viruses
Anticancer activity and used for the
treatment of Alzheimer’s disease
Antineoplastic activity 5-Lipoxygenase inhibition.
Antitumor properties Tubulin polymerization results in arrest of cell cycle and
Anti-inflammatory, antioxidant,
cardiovascular, antiulcer, Alzheimer’s
disease, antimicrobial, antiallergic, and
anticancer activity
Used in chronic pain syndromes like
musculoskeletal pain and postherpetic
neuralgia
Antidiabetic, antioxidant,
chemotherapeutic, and chemopreventive
agent which is used for the treatment
of cancer forms, also used in metabolic
syndrome and cardiovascular complications
⏎
153
CB1 and CB2 modulation, presence of 5HT1A
receptors in the central nervous system.
modulation of anti-inflammatory properties.
formation.
Viral membrane is the main target of any modifications
or damage to viral particles. Lipid layers in bacterial
cell walls are also disrupted, and dihydrofolate
reductase is inhibited. NF-kB signaling is inhibited and
reactive oxygen species (ROS) generation is modified
to produce anticancer action.
Apoptosis induction, inhibition of protein tyrosin
kinase, antiangiogenic and antimetastatic activity,
antioxidant property, and cell cycle arrest.
suppresses the mitotic spindle microtubule formation.
Cyclooxygenase and lipoxygenase inhibition, inhibition
of platelet aggregation and gastric secretion along with
lipid peroxidation, generation of ROS and elevation of
microRNA 21.
Transient receptor potential activates the vanilloid 1
receptor (TRPV1) in particular sensory nerve.
Multiple molecular pathway modulation in the
metabolism of xenobiotics and cancer, reduction in
oxidative stress, apoptosis induction, cell proliferation
arrest, and inflammation.
TABLE 8.1
Sr.
No.
11. Ingenol mebutate
12. Paclitaxel
13. Masoprocol
14. β-Lapachone
15. Gossypol
(Continued)
Natural
Compound
Botanical Name
(Common Name)
Euphorbia peplus L.
(Petty spurge)
Taxus brevifolia Nutt.
(Pacific yew)
Larrea tridentate
(Creosote brush)
Tabebuia avellanedae
(Lapacho tree)
Gossypium hirsutum L.
(Cotton plant)
Therapeutic Value Mechanism of Action
Actinic keratosis Local proinflammatory response, cell death necrosis
inducer. and dual mechanism.
Cancer chemotherapy Mitotic inhibitor.
Antineoplastic agent in cancer
chemotherapy
Antitrypanosoma, anticancerous,
antimalarial, and antimicrobial activity
Anticancerous, antioxidant, antimicrobial,
antiviral, and antiinfertility/male
contraceptive
Inhibition of 5-Lipoxygenase.
Anticancer activity is demonstrated by the formation
of ROS in positive NQO1 cells, a modulator of mTOR
pathway, and inhibition of topoisomerase activity.
Inhibition of Bcl-2, induction of apoptosis, DNA
topoisomerase II and polymerase inhibition, and
inhibition of sperm motility and production.
154
155
8.2 SCENARIO OF DRUG DISCOVERY
Drug development is no longer only dependent on chance or emerging technologies. Making
a substantial change requires a better grasp of diverse methodologies, crucial historical
lessons, and the proper future strategy (Schmid and Smith, 2004). Analysts predict that
pharmaceutical-biotechnology agreements will continue to be formed in order to assist
grow pipelines because the biotechnology sector has produced a significant number of
approved new medication applications in recent years (Hughes, 2009). In a similar vein,
approximately half of the small compounds authorized in this decade have come from NPs.
Changing the current drug development method from finding “ new entity medications”
to “ combining existing agents” may be advantageous, according to some. As a result, it is
thought that generating NP medications based on conventional therapies and ethnopharmacology is a very good choice for drug development.
8.3 EFFICIENT DRUG DISCOVERY ENGINES
The era of the top-selling medications appears to be a distant memory (Thayer, 2004). For
instance, the United States Food and Drug Administration (US FDA) only authorized 21
novel molecular entities in 2008, and very few of these are expected to be blockbusters.
It is possible that today’s breakthrough and me too drug distinctions are not very useful
(DiMasi and Paquette, 2004) postapproval or postmarketing removal of novel medications
persists despite extremely strict and rigorous regulatory processes. It is stated that until a
medicine has been on the market for several years, its safety cannot be determined with
assurance. This prompted a review of the drug regulating process and raised concerns
that the existing system is insufficient for safeguarding the public’s health (Ray and
Stein, 2006). The briefings given to the Drug Advisory Committee and the US FDA (US
FDA Drug Watch) on the new anticoagulant Ximelagatran from AstraZeneca, the Cox II
inhibitor V ioxx from Merck, and the case of the cancer vaccination Dendreon’ s provenance
approvals are frequently illuminating. As the pharmaceutical industry’s R&D output is
declining, societal expectations for therapeutic effectiveness and safety are growing. The
FDA’s Critical Path Initiative was established with the intention of modernizing medicine
development by integrating contemporary scientific breakthroughs. It exemplifies a proac-
tive policy strategy to boost innovation prospects in a public/private partnership paradigm
(W oodcock and Woosley, 2008). W e contend that conventional medicine may provide more
efficient means of finding, creating, and delivering novel medications with improved cost,
safety, and effectiveness profiles. To this purpose, we think that the fundamental ideas,
practical knowledge, holistic strategy, and structured database of Ayurveda may provide
practical bioprospecting tools and a successful discovery engine.
8.4 DRUG DISCOVERY APPROACHES USING PLANTS
Although the majority of these studies concentrate on screening plants for anticancer or
anti-HIV activity, there have been a number of studies on approaches for selecting plants
156
as prospective candidates for drug development programs (Kopaci, 2012). It is without
a doubt necessary that early listing of candidate species for biological activity screening
be made. According to calculations conducted by Katiyar et al. (2021), the following
techniques are now being used by researchers to achieve this goal.
8.4.1 PLANT SELECTION FOR SCREENING PURPOSE
The plant selection for active component extraction and isolation is a crucial step in the
process of creating medicines from plant sources. Despite the enormous diversity of
plant species, Fabricant and Farnsworth (2001) have noted that only a tiny portion of
those currently accessible plant species have been examined for their biological activity.
Researchers have used a variety of methods for choosing plant candidates for drug development to get around this, and these methods consist of:
• Ethnobotanical approach: The strategy to research the connections between
humans and plants is called ethnobotany . It entails analyzing the ways that knowledge
is passed down through the generations and how various cultures employ plants for
nutritional, medicinal, and other purposes. This method includes choosing plants
based on their traditional uses in local medical systems. Indigenous healers or
practitioners of traditional medicine are frequently contacted to determine which
plants have been utilized historically to cure particular conditions. This strategy
is frequently utilized as a starting point for drug development and is particularly
helpful in regions where traditional medicine is still commonly practiced.
Studies in ethnobotany concentrate on the cultural importance of plants as well as
the ecological and environmental variables that affect their variety and distribution.
To develop a comprehensive knowledge of the intricate connections between
humans and the natural world, this method combines parts of ethnography—the
study of human cultures—and botany—the study of plants. In order to record and
preserve local populations’ traditional knowledge of plants and their applications,
ethnobotanists frequently collaborate closely with indigenous and local groups.
The ethnobotanical method has significant implications for sustainability and
conservation. Researchers may develop ways to assist local livelihoods and promote
biodiversity conservation by comprehending how people utilize and value plants.
Having an understanding of ethnobotany can help in the creation of novel drugs and
other plant-based goods.
The identication of plants with possible medicinal characteristics is aided by
the ethnobotanical method, which is frequently utilized in the drug development
process. Here are some instances of how ethnobotanical knowledge has aided in the
creation of medicines:
1. Artemisinin: In Chinese medicine, the herb Artemisia annua, which yields
the chemical artemisinin, has long been used to treat fever and malaria. The
discovery of this plant as a possible source of antimalarial medications goes to
ethnobotanical research which sparked the creation of combination medicines
based on artemisinin, which are currently the first-line therapy for malaria.
157
2. Taxol: First extracted from the Pacific yew tree’s bark, taxol is a chemotherapeutic medication used to treat various cancers. The Pacific yew was discovered
to be a potential source of anticancer medications thanks to ethnobotanical
research, which also sparked the creation of Taxol.
3. Curcumin: Turmeric contains an active component called curcumin, frequently
used in conventional Indian medicine. Curcumin-based therapies were created
as a result of ethnobotanical studies that identified turmeric as a potential source
of anti-inflammatory and anticancer medications.
4. Reserpine: It is a chemical derived from the Indian snakeroot plant that has been
used to treat hypertension and other conditions in traditional Indian medicine.
Ethnobotanical investigations helped to identify Indian snakeroot as a possible
source of antihypertensive medicines, which led to the creation of reserpine.
• Chemotaxonomic approach: In order to identify the evolutionary links between
plants, the chemotaxonomic approach, a technique for classifying plants, analyzes
chemical substances found in plant tissues, such as alkaloids, flavonoids, and terpenoids. In this method, plants are chosen based on their taxonomic status and known
phytochemical components. Similar secondary metabolites are frequently found
in plants of the same family or species, and these plants may also share similar
biological functions. This method is frequently used with the ethnobotanical method
to reduce the number of plants that need to be screened. This strategy is based on the
idea that plants with similar chemical makeup are probably related.
The chemotaxonomic method has the following salient characteristics:
• Chemical evaluation: Chemotaxonomic investigations examine plant tissues to
find and measure certain chemical components. These substances serve as helpful
categorization markers since they are frequently exclusive to particular plant families or genera.
• Relationships in terms of evolution: Chemotaxonomic studies look for patterns of
chemical similarity that can be used to infer relationships in terms of plant evolution. For instance, two plants are considered to be closely related and may belong
to the same family or genus if their chemical profiles are comparable. Chemotaxonomic information can be utilized to support or contradict conventional taxonomic
classifications based on morphology and other traits. This strategy can aid in the
improvement of taxonomic classifications and the discovery of novel connections
between plant groupings.
• Applications in practice: The chemotaxonomic method has applications in practice
in the disciplines of botany , pharmacology , and agriculture. For instance, chemotaxonomic research can be used to find plants that may have medical use or to create new
plant types with desirable characteristics.
Drug development has made use of the chemotaxonomic technique to nd novel chemi-
cals with potential medicinal effects. These are a few instances:
• Vinca alkaloids: The Madagascar periwinkle plant contains compounds called vinca
alkaloids, which are used to make chemotherapy medications including vinblastine
158
and vincristine. These alkaloids were found in the plant using the chemotaxonomic
method, which led to the identification of them as possible anticancer drugs.
• Salicylates: Aspirin and other salicylates are often used as anti-inflammatory and
painkilling medications. Following their initial isolation from the willow tree’s bark,
these substances were later discovered in other plants thanks to the chemotaxonomic
method.
• Taxanes: Chemotherapy medications such as paclitaxel are known as taxanes
and are used to treat various cancers. The Pacific yew tree served as the source
of these chemicals’ first isolation, and the chemotaxonomic technique enabled the
identification of additional taxanes-containing species, including the European and
Himalayan yews.
• Quinine: It is an antimalarial medication made from the cinchona tree’s bark. The
identification of novel antimalarial chemicals was made possible by the use of the
chemotaxonomic technique, which allowed to identify the existence of quinine and
similar alkaloids in other plants.
• Random selection strategy: In this strategy , plants are chosen at random for screening
without any knowledge of their chemical or biological characteristics beforehand.
This method is frequently applied in HTS programs where the biological activity of
many plant extracts is evaluated.
• Target‑based strategy: In this strategy, plants are chosen based on their known or
suspected action against a particular target. Plants that are known to block a certain
enzyme or receptor, for instance, may be chosen for screening. In drug discovery projects
when a particular target has already been identified, this strategy is frequently utilized.
• Ecological approach: Using an ecological strategy, plants are chosen according to
their environment and ecological niche. Extreme conditions, such as deserts or high
altitudes, can cause plants to develop secondary metabolites with particular biological
properties. This method is frequently used to find new bioactive substances.
It is essential to remember that choosing which plants to screen is a crucial phase in the
drug development process. The technique to be used will rely on the precise research goals,
the resources at hand, and the characteristics of the target illness.
8.4.2 AUTHENTICATION OF PLANTS
The use of the proper herbal species and plant parts as the basis for herbal products is
ensured by the quality assurance process known as herbal authentication. Also, accurate
identification of the herbal plants that are used to create NPs is essential to the field of
research and medicine as a whole. To make sure that the raw materials used in completed
products are appropriate for their intended application, it is also important to identify
herbal plants as the raw materials (Smillie and Khan, 2010). Applying a precise authentication procedure to ensure that the herbs used as materials are correct and authentic before
any operations is also crucial if the quality and safety of the final natural goods are to be
guaranteed. The proximity of different constituents in the chemical can be determined by
the types of adulterants used as a simple procedure, which includes examining the specific
159
properties adequate to authenticate some medications organoleptically, while other drugs
may need a more involved method. As a result, it is up to researchers to select a technique
that is suited for the topic.
Popular techniques for determining the veracity of herbs include examinations at the
microscopic and macroscopic levels such as morphological and analogical examination,
organoleptic characteristics, DNA-based techniques, chemical ngerprinting, and many
others. Yet, for the purposes of authentication, various techniques will have varying roles
and some disadvantages. The rst step in the authentication procedure is to determine the
medicinal plant’s botanical origin and establish its scientic binomial name (Techen et al.,
2014. Comparing the plant material’s organoleptic features, such as shape, taste, surface
properties, color, texture, aroma, size, fracture characteristics, with recognized reference
material allows for macroscopic identication.
Typically, very identical medicinal plants are distinguished and identied by the use of
microscope. In this method, intrinsic structural properties at the tissue and cellular levels
are swiftly and simply identied. Usually, a conventional light microscope is adequate for
this purpose but sometimes polarized and uorescent microscopes are also used in order to
improve the accuracy of detection (Heinrich and Anagnostou, 2017).
Quantitative and qualitative analysis of natural compounds is carried out by chromatographic techniques including capillary electrophoresis (CE), high-performance liquid
chromatography (HPLC), thin-layer chromatography (TLC), and high-performance thin
layer chromatography. The gas chromatographic method is used to test volatile herbal
medications that include important principles. TLC provides an initial ngerprint of the
NP, and it is advantageous since it is simple and can evaluate multiple samples in one go.
Natural medicine’s volatile components offer the necessary ngerprints that can be used
to identify plants. CE is advantageous because of its high separation efciency, minimal
material requirement, and high speed of analysis. Undoubtedly higher level indicators are
DNA-based markers that are based on an investigation of the individual’s genetic makeup
since they are unaffected by aging, the environment, and physiological factors (Sgamma
et al., 2017). Because they are not tissue-specic, these markers can also be discovered at
any stage of plant growth. Because these may be automated, DNA-based technology can
provide an efcient, precise, and less expensive way to test the validity of numerous samples
at once in comparison to phenotypic and chemical indicators. The safety monitoring and
quality control of herbal medicines and nutraceuticals would signicantly increase the
medical potential and commercial feasibility of medicinal plants.
A nucleotide sequence or a gene is a genetic marker on a chromosome that can identify
between cells, humans, or species. Due to the extreme specicity of DNA sequences, these
can be recognized with the aid of particular molecular markers that can distinguish one
unique DNA sequence from a collection of unknowns.
8.4.3 TYPES OF MOLECULAR MARKERS
The most common molecular markers include amplified fragment length polymorphisms
(AFLPs), intersimple sequence repeats (ISSRs), randomly amplified polymorphic DNA
160
(RAPD), simple sequence repeats (SSRs), single nucleotide polymorphisms, sequence
characterized amplified regions (SCARs), loop-mediated isothermal amplification (LAMP)
and others (Table 8.2) (Figure 8.2). DNA barcoding, microarray-based markers, and Next
Generation Sequencing-based markers are recent breakthroughs. No DNA marker may be
regarded as optimal because each methodology faces different methodological, technological, and material challenges and is either directed at a specific region of the genome
or is wholly arbitrary. So, the research objectives determine whether to utilize a particular
marker (Table 8.3).
8.5 FRACTIONATION DIRECTED BY BIOLOGICAL ACTIVITY FOR NATURAL
COMPOUND EXTRACTION AND ISOLATION
Extraction is the first and most crucial step in creating medical plant-based drugs since it
is essential to distinguish and characterize the necessary chemical components from the
plant materials. The basic method involved steps including prewashing, freeze-drying, or
drying of plant material, grinding to provide a homogenous sample, and often enhancing
the kinetics of analytical extraction as well as increasing the contact of the sample surface
with the solvent system. In order to prevent possible active ingredients from being lost,
altered, or destroyed during the extraction of plant samples, the appropriate steps must
be taken (Harvey, 1999). As a result of the expanding interest in the plant world as a
potential source of new therapeutic medicines, numerous techniques for the extraction
and isolation of NPs have been created. There has been a lot of use of chromatographic
separation methods related to biological activity-guided fractionation and isolation. The
fractionation of the plant extract is carried out by a particular form of biological activity
instead of a component of interest and entails a sequential separation of the used plant
extract. Further fractionation and screening are carried out based on physicochemical
parameters and screening for biological activity. Only the fractions with noticeable
biological activity are processed further to obtain the pure isolate that is responsible for
the required biological activity after all fractions have first been evaluated for biological
activity. Two main approaches are used in experimental methods to find known or
unknown substances which can be used as structures of lead or drugs for the creation
of novel analogues with enhanced drug-like properties. However, alternative strategies
can also be applied depending on the situation. These two strategies are listed below
(Lawrence, 1999).
8.5.1 PARALLEL APPROACH
This strategy is employed when the biological activities of the chosen plants are known
via traditional or ethnopharmacological knowledge. As shown in Figure 8.3, the target
activity’s active components are separated from the raw plant material. In general, the
following three steps are used, that is, extraction of compounds, their isolation, and final
purification step.
161
TABLE 8.2 Different DNA Markers Comparative Analysis
Abundance in
genome
Quantity of genomic
DNA required
Inheritance pattern
Type of primers or
probes used
Polymorphism
observed
Rate of
reproducibility
Use in sequencing or
cloning
Usability
Restriction
Fragment Length
Polymorphism
(RFLP)
Highly abundant Highly
2–5 μg 15–30 ng 200–300 ng 15–30 ng 30–50 ng 30–50 ng 10–20 ng 30–50 ng
Codominant Dominant Dominant Dominant Codominant Codominant Codominant NA
Specific sequence Random
Changes in
nucleotide bases
that impact
restriction
endonuclease
specificity
Highly
reproducible
Used Not used Not used Not used Used Used Used Used
Laborious Quite easy Initially difficult Quite easy Very easy Quite easy Quite easy Quite easy
RAPD AFLP ISSR SSR SCAR LAMP DNA‑
abundant
sequence
Primer binding
sequences
which include
nucleotide base
changes
Very low
reproducible
⏎
Barcoding
Technique
Moderate Moderate Moderate Abundant Abundant Abundant
Specific to a particular
adapter sequence
Base alterations in
nucleotides that impact
restriction endonuclease
specificity and the
existence or absence of a
nucleotide complementary
to particular nucleotides
High reproducible Medium
Specific
sequence
Base changes
in nucleotides
at primers
binding
sequences
reproducible
Specific
sequence
Complete
DNA
fragment
presence or
absence
Highly
reproducible
Specific
sequence
Complete
presence
or absence
of a DNA
segment
Highly
reproducible
Specific
sequence
Complete
presence
or absence
of a DNA
segment
Highly
reproducible
Specific
sequence
Variations in
nucleotides
in universal
genes
Highly
reproducible
TABLE 8.3 Utilizing Molecular Markers to Confirm the Identity of Therapeutic Plant Species
Name of the
Authentic
Drug Source
Litchi Drupe Antifungal, anticancer,
Chocolate vine Stalk Analgesic, antiphlogistic, and
Malva Branca Leaves and
Andaliman and
Prickly ash
Velvet Leaf Entire plant
Moldavian
dragonhead
Bankakri Rhizome Antitumor characteristics
Yellow
Himalayan
fritillary
Qian Hu Rhizome Prevents or relieves cough Cow Parsley DNA-
Type of
Plant Part
Used
root system
Entire plant
is used
is used
Entire plant
is used
Bulb Expectorant and prevents or
Used for Medicinal Purpose Presence of Any Kind
anti-inflammatory, antiviral,
antioxidant, anticoagulant,
antidiabetic, and antiplatelet
properties are present in fruit
and its secondary metabolites.
diuretic properties.
Antidiabetic properties,
antioxidants, and antiinflammatory nature.
Blood purifier, reduce the
incidence of leukoderma and
stomach trouble
Fever, stomach pain, cardiac
pain, and skin conditions
Analgesic and against
coronary diseases
relieves cough
Marker Used Application References
of Adulterants or
Substituent
Not present SCAR or
RAPD marker
Clematis armandii,
Akebia trifoliata,
and Aristolochia
manshuriensis
Sida rhombifolia and
Abuliton indicum
Not present AFLP marker Species-specific authentication
Stephania japonica and
Cyclea peltata
Nepeta cataria L. and
Melissa officinalis
Podophyllum peltatum
L.
Yibeimu, Zhebeimu,
Hubeibeimu, and
Pingbeimu
SCAR or
RAPD marker
Barcoding of
DNA
RAPD marker Identification using RAPD
RFLP marker Authentication using RFLP Horn et al. (2014)
RAPD SCAR
markers
RAPD SCAR
marker
barcoding
technique
⏎
Identification by molecular
cloning and RAPD
amplification
Authentication of its species
on the basis of multiplexpolymerase chain reaction and
RAPD-derived SCAR markers
species identification using
DNA barcoding from dried and
powdered parts of plant
using AFLP markers
markers of “ Patha”
Identification and authentication
using SCAR marker
Authentication by RAPDderived DNA markers.
Authentication using
DNA-barcoding technique
Cheng
et al. (2015)
Moon et al. (2015)
Vassou et al. (2015)
Gupta and Mandi
(2013)
Vijayan et al. (2013)
Al-Shaqha et al.
(2014)
Xin
et al. (2014)
Zhou et al. (2014)
162