ArticlePDF Available

Abstract

Secondary metabolites (SM) are compounds that are not necessary for a cell (organism) to live, but play a role in the interaction of the cell (organism) with its environment. These compounds are often involved in plants protection against biotic or abiotic stresses. Secondary metabolites are from different metabolites families that can be highly inducible in response to stresses. Primary metabolites perform essential metabolic roles by participating in nutrition and reproduction. A few SMs are used as especially chemical such as drugs, flavours, fragrances, insecticides, and dyes and thus have a great economic value. These new technologies will serve to extend and enhance the continued usefulness of the higher plants as renewal sources of chemicals, especially medicinal compounds. A continuation and intensification efforts in this field is expected to lead to successful biotechnological production of specific, valuable and as yet unknown plant chemicals. © 2015 Current Trends in Biotechnology and Pharmacy. All rights reserved.
www.IndianJournals.com
Members Copy, Not for Commercial Sale
Downloaded From IP - 117.240.114.66 on dated 11-Aug-2016
Current Trends in Biotechnology and Pharmacy
Vol. 9 (3) 293-304 July 2015, ISSN 0973-8916 (Print), 2230-7303 (Online) 294
Abstract
Secondary metabolites (SM) are
compounds that are not necessary for a cell
(organism) to live, but play a role in the interaction
of the cell (organism) with its environment. These
compounds are often involved in plants protection
against biotic or abiotic stresses. Secondary
metabolites are from different metabolites
families that can be highly inducible in response
to stresses. Primary metabolites perform
essential metabolic roles by participating in
nutrition and reproduction. A few SMs are used
as especially chemical such as drugs, flavours,
fragrances, insecticides, and dyes and thus have
a great economic value. These new technologies
will serve to extend and enhance the continued
usefulness of the higher plants as renewal
sources of chemicals, especially medicinal
compounds. A continuation and intensification
efforts in this field is expected to lead to
successful biotechnological production of
specific, valuable and as yet unknown plant
chemicals.
Keywords: Secondary metabolites, drugs,
flavours, fragrances, biotechnology
Introduction
Plants possess capacity to synthesize
different organic molecules called secondary
metabolites. Unique carbon skeleton structures
are basic properties of plant secondary
metabolites. Secondary metabolites are not
necessary for a cell (organism) to live, but play a
role in the interaction of the cell (organism) with
its surroundings, ensuring the continued
existence of the organism in its ecosystems.
Formation of SMs is generally organ, tissue and
cell specific and these are low molecular weight
compounds. These compounds often differ
between individuals from the same population
of plants in respect of their amount and types.
They protect plants against stresses, both biotic
(bacteria, fungi, nematodes, insects or grazing
by animals) and abiotic (higher temperature and
moisture, shading, injury or presence of heavy
metals). SMs are used as especially chemical
such as drugs, flavours, fragrances, insecticides,
and dyes by human because of a great economic
value.
In plants, SMs can be separated into three
groups (Terpenoids, Polyketides and
Phenypropanoids) based on their biosynthesis
origin (1). Alkaloids are additional class of SMs,
which are nitrogenous organic molecules
biosynthesized mainly from amino-acids, e.g.,
tryptophan, tyrosine, phenylalanine, lysine and
arginine using many unique enzymes (2). Many
of the most important therapeutic agents are
alkaloids. The sites of biosynthesis are
compartmentalised at cellular or sub-cellular
level. However SMs can be transported long
distances and accumulate from their location of
synthesis.
Primary Vs Secondary Metabolites : Primary
metabolites are found in all plants and execute
vital metabolic responsibilities, by participating in
Secondary Metabolites of Plants and their Role:
Overview
Saurabh Pagare1*, Manila Bhatia1, Niraj Tripathi2, Sonal Pagare3 and Y.K. Bansal1
1Department of Biological Science, Rani Durgavati Vishwavidyalaya,
Jabalpur (M.P.)-482001, India
2Directorate of Weed Science Research, Jabalpur (M.P.)-482004, India
3NTPC Hospital,Korba (C.G.)-495450, India
*For Correspondence - saurabhhind@gmail.com
Secondary Metabolites of Plants and their Role
www.IndianJournals.com
Members Copy, Not for Commercial Sale
Downloaded From IP - 117.240.114.66 on dated 11-Aug-2016
Current Trends in Biotechnology and Pharmacy
Vol. 9 (3) 293-304 July 2015, ISSN 0973-8916 (Print), 2230-7303 (Online) 295
nutrition and reproduction (2). Sometimes it is
hard to discriminate primary and secondary
metabolites. For example, both primary and
secondary metabolites are found among the
terpenoids and the same compound may have
both primary and secondary roles. Secondary
metabolites are broad range of compounds from
different metabolite families that can be highly
inducible in stress conditions. Carotenoids and
flavonoids are also involved in cell pigmentation
in flower and seed, which attract pollinators and
seed dispersers. Therefore, they are also
involved in plant reproduction (3). Plant primary
products refer to the compounds of nucleic acids,
proteins, carbohydrates, fats and lipids and are
related to structure, physiology and genetics,
which imply their crucial role in plant
development. In contrast, secondary metabolites
usually take place as minor compounds in low
concentrations. Primary metabolism refers to the
processes producing the carboxylic acids of the
Krebs cycle. Secondary metabolites, on the other
hand, are non-essential to life but contribute to
the species’ fitness for survival. In fact, the
specific constituents in a certain species have
been used to help with systematic determination,
groups of secondary metabolites being used as
markers for botanical classification
(chemotaxonomy). Plants secondary metabolites
can be divided into three chemically distinct
groups viz: Terpenes, Phenolics, N (Nitrogen) and
S (sulphur) containing compounds.
I)Terpenes : Terpenes comprise the biggest
group of secondary metabolites and are free by
their common biosynthetic origin from acetyl-coA
or glycolytic intermediates. An immense bulk of
the diverse terpenes structures produced by
plants as secondary metabolites that are
supposed to be concerned in defense as toxins
and feeding deterrents to a large number of plant
feeding insects and mammals. Terpenes are
divided into monoterpenes, sesquiterpenes,
diterpene, Triterpenes and polyterpenes. The
pyrethroid (monoterpenes esters) occur in the
leaves and flowers of Chrysanthemum species
show strong insecticidal responses to insects like
beetle, wasps, moths, bees, etc and a popular
ingredient in commercial insecticides because
of low persistence in the environment and low
mammalian toxicity. In Gymnoperms (conifers)
á-pinene, â-pinene, limonene and myrecene are
found. A number of sesquiterpenes have been
till now reported for their role in plant defense
such as costunolides are antiherbivore agents
of family composite characterized by a five
member lactone rings (a cyclic ester) and have
strong feeding repellence to many herbivorous,
insects and mammals. ABA is also a
sesquiterpene plays primarily regulatory roles in
the initation and maintenance of seed and bud
dormancy and plants response to water stress
by modifying the membrane properties and act
as a transcriptional activator (4). Abietic acid is a
diterpene found in pines and leguminous tress.
It is present in or along with resins in resin canals
of the tree trunk . Another compound phorbol
(Diterpene ester), found in plants of
euphorbiaceae and work as skin irritants and
internal toxins to mammals. The milkweeds
produce several better tasting glucosides
(sterols) that protect them against herbivors by
most insects and even cattle. Several high
molecular weight polyterpenes occur in plants.
The principal tetraterpenes are carotenoids
family of pigments.
(II) Phenolic compounds : Plants produce a
large variety of secondary products that contain
a phenol group, a hydroxyl functional group on
an aromatic ring called Phenol, a chemically
heterogeneous group also. They could be an
important part of the plants defence system
against pests and disease including root parasitic
nematodes (5). Elevated ozone (mean 32.4ppb)
increased the total phenolic content of leaves and
had minor effects on the concentration of
individual compounds (6).Coumarin are simple
phenolic compounds widespread in vascular
plants and appear to function in different
capacities in various plant defense mechanisms
against insect herbivores and fungi. They derived
from the shikimic acid pathway, common in
bacteria, fungi and plants but absent in animals
Saurabh Pagare et al
www.IndianJournals.com
Members Copy, Not for Commercial Sale
Downloaded From IP - 117.240.114.66 on dated 11-Aug-2016
Current Trends in Biotechnology and Pharmacy
Vol. 9 (3) 293-304 July 2015, ISSN 0973-8916 (Print), 2230-7303 (Online) 296
(7). Some coumarin derivatives have higher anti-
fungal activity against a range of soil borne plant
pathogenic fungi and exhibit more stability as
compared to the original coumarin compounds
alone (7). Furano is Also a type of coumarin with
special interest of phytotoxicity, abundant in
members of the family umbelliferae including
celery parsnip and parsley. Psoraline, basic linear
furacoumarin, known for its use in the treatment
of fungal defence and found very rarely in SO2
treated plants (8). Ligin is a highly branched
polymer of phenyl- propanoid groups, formed
from three different alcohols viz., coniferyl,
coumaryl and synapyl which oxidized to free
radical (ROS) by a ubiquitous plant enzyme-
peroxidises, reacts simultaneously and randomly
to form lignin. Its physical toughness deters
feeding by herbivorous animals and its chemical
durability makes it relatively indigestible to
herbivorous and insects pathogens. Lignifications
block the growth of pathogen and are a frequent
response to infection or wounding. Flavanoids
perform very different functions in plant system
including pigmentation and defence. Two other
major groups of flavanoids found in flowers are
flavanones and flavanols function to protect cell
from UV-B radiation because they accumulate
in epidermal layers of leaves and stems and
absorb light strongly in the UV-B region while
letting visible (PAR) wavelengths throughout
uninterrupted (9). In addition exposure of plants
to increased UV-B light has been demonstrated
to increase the synthesis of flavanones and
flavanols suggesting that flavanoids may offer
measures of protection by screening out harmful
UV-B radiation (6). Isoflavanoids are derived from
a flavanones intermediate, naringenin,
ubiquitously present in plants and a play a critical
role in plant developmental and defence
response. They secreted by the legumes and play
an important role in promoting the formation of
nitrogen fixing nodules by symbiotic rhizobia (10).
Moreover, it seems that synthesis of these
flavanoids is an effective strategy against reactive
oxygen species (ROS). The analysis of activity
of antioxidant enzymes like SOD, CAT, POX,
APX, GPX and GR suggested that peroxidases
were the most active enzymes in red cabbage
seedlings exposed to Cu++ stress (11).Tannins
included in the second category of plant phenolic
polymers with defensive properties. Tannins are
general toxins that significantly reduce the growth
and survivorship of many herbivores, and also
act as feeding repellents to a great diversity of
animals.
(III) Sulphur containing secondary
metabolites: They include GSH, GSL,
Phytoalexins, Thionins, defensins and allinin
which have been linked directly or indirectly with
the defence of plants against microbial pathogens
(12,13,14). GSH is the one of the major form of
organic sulphur in the soluble fraction of plants
and has an important role as a mobile tool of
reduced sulphur in the regulation of plant growth
and development and as a cellular antioxidants
in stress responses (15), reported as a signal of
plant sulphur sufficiency that down regulates
sulphur assimilation and sulphur uptake by roots.
GSL is a group of low molecular mass N
(nitrogen) and S (sulphur) containing plant
glucosides that produced by higher plants in order
to increase their resistance against the
unfavourable effects of predators, competitors
and parasites because their break down products
are release as volatiles defensive substances
exhibiting toxic or repelient effects for example,
mustard oil glucosides in cruciferae and allyl cys
sulfoxides in alllum (16). They are metabolised
and absorbed as isothiocyanates that can affect
the activity of enzymes involved both in the
antioxidant defence system and in the
detoxification from zenobiotics abd significantly
affect GST activity and cell protection against
DNA damage (17) whereas toxicity of
glucosinolatic products is well documented but
their mode of action has not yet been elucidated
and results from experiments with Brassica
plants modified in GSL content generated doubts
about their contribution to plant defences.
Phytoalexins are synthesized in response
to bacterial or fungal infection or other forms of
stress that help in limiting the spread of the
Secondary Metabolites of Plants and their Role
www.IndianJournals.com
Members Copy, Not for Commercial Sale
Downloaded From IP - 117.240.114.66 on dated 11-Aug-2016
Current Trends in Biotechnology and Pharmacy
Vol. 9 (3) 293-304 July 2015, ISSN 0973-8916 (Print), 2230-7303 (Online) 297
invading pathogens by accumulating around the
site of infection, appears to a common
mechanism of resistance to pathogenic microbes
in a wide range of plants. Many of these changes
are linked to a rapid apoptotic response, resulting
in death of one or a few invaded plant cells,
known as the hypersensitive response (HR).
Most plant families produce organic phytolexins
of diverse chemistry; these groups are often
associated with a family, for example
sesquiterpenoids of Solanaceae, isoflavonoids
of Leguminosae, while phytoalexins from
Brassica have an indole or related ring system
and one S atom as common structural features.
Crucifereae appears to be the only plant family
producing these S metabolites, which are clearly
different from the other well- known
GSL.Cruciferous crops are cultivated worldwide
because they are extremely valuable and for the
last decades, various research groups have
investigated cruciferous phytoalexins as well as
their biological activity.Typically, there are multiple
responses involving several related derivatives
such as up to nine wyerone (Furano-acetylenic
derivatives) forms in Vicia fava and several forms
of phaseollin in Phaseolus vulgaris and glyceollin
in Glycine max, postin in Pisum sativum pods,
Ipomearone in sweet pototo, orchinol in orchid
tubers, trifolirhizin in red clover. Defensins,
thionins and lectins are S-rich non-storage plant
proteins synthesize and accumulate after
microbial attack and such related situations. They
inhibit growth of a broad range of fungi.
Additionally defensins genes are partly pathogen-
inducible and others that are involved in
resistance can be expressed constitutively. Some
plant species produce lectins as defensive
proteins that bind to carbohydrates or
carbohydres containing proteins.
(IV) Nitrogen containing secondary
metabolites: They include alkaloids, cyanogenic
glucosides, and non-proteins amino-acids. Most
of them are biosynthesized from common amino-
acids. Alkaloids found in approximately 20% of
the species of vascular plants, most frequently
in the herbaceous dicot and relatively a few in
monocots and gymnosperms. Generally, most of
them, including the pyrrolizidine alkaloids (PAs)
are toxic to some degree and appear to serve
primarily in defense against microbial infection
and herivoral attack. Cyanogenic glucosides
constitue a group of N-containing protective
compounds other than alkaloids, release the
poison HCN and usually occur in members of
families viz., Graminae, Roosaceae and
leguminosesae. They are not themselves toxic
but are readily broken down to give off volatile
poisonous substance like HCN and volatile H2S
when the plant crushed; their presence deters
feeding by insects and other herbivorous such
as snails and slugs. Amygdalin, the common
cynogenic glucoside found in the seeds of
almonds, apricot, cherries and peaches while
Dhurrin, found in Sorghum bicolar.
Many plants also contain unusual amino acids
called non-protein amino-acids that incorporated
into proteins but are present as free forms and
act as protective defensive substance. For
examples, canavanine and azetidine-2 carboxylic
acid are close analogs of arginine and proline
respectively. They exert their toxicity in various
ways. Some block the synthesis of or uptake of
protein amino acid while others can be mistakenly
incorporated into proteins. Plants that
synthesized non-protein amino acid are not
susceptible to the toxicity of these compounds
but gain defence to herbivorous animals, insects
and pathogenic microbes.
Transport, Storage and Turnover: SMs can
be water soluble (hydrophilic) compounds or
lipophilic (needs organic solvents), therefore
needs different cellular mechanism for their
transport, storage and turnover. Most substances
are synthesized in the cytoplasm, the ER or in
the organelles. Hydrophilic SMs are usually
stored in the vacuole after their formation in
cytoplasm, whereas lipophilic substances are
sequestered in resin ducts, laticifers, glandular
hairs, trichomes, thylakoid membranes or on the
cuticle. Hydrophilic SMs have to pass the
tonoplast, which is impermeable to many of the
polar secondary metabolites. For some alkaloids
Saurabh Pagare et al
www.IndianJournals.com
Members Copy, Not for Commercial Sale
Downloaded From IP - 117.240.114.66 on dated 11-Aug-2016
Current Trends in Biotechnology and Pharmacy
Vol. 9 (3) 293-304 July 2015, ISSN 0973-8916 (Print), 2230-7303 (Online) 298
and flavanoids, a specific transporter has been
described, which pumps the compounds into the
vacuole. In order to avoid autotoxicity, plants
cannot store these compounds in the vacuole
but usually sequester them on the cuticle, in dead
resin ducts or cells which are lined by a
biomembrane but an impermeable solid barrier.
In many instances, the site of biosynthesis is
restricted to a single organ such as roots, leaves
or fruits, but an accumulation of the
corresponding products can be detected in
several other plant tissues. Long distance
transport must take place in these instances. The
xylem or phloems are likely transport routes but
an apoplastic transport can also be involved.
Storage can also be tissue and cell- specific,
depending upon the protection providing to the
plants.In a number of plants, specific idioblasts
have been detected that contain tannins,
alkaloids or glucosinolates. More often, SMs are
concentrated in trichomes or glandular hairs
(many terpenoids in Labiatae, Asteraceae),
stinging hairs (many amines in urticaceae) or the
epidermis itself (many alkaloids, flavanoids,
anthocyanins, cynogenic glycosides, coumarins,
etc.) flowers, fruits and seeds are usually rich in
SMs, especially in annual plants. In perennial
species, high amounts of SMs found in bulbs,
roots, rhizomes and the bark of roots and stems.
It is well-established that profiles of SMs vary with
time, space and developmental stage. Since
related plant species often show similarities in
the profiles of their SMs, they have been used
as taxonomic tool in plant systematic. However,
profiles of closely- related plants quite often differ
substantially or those of unrelated plant group
show strong similarities; this clearly shows that
SM patterns are not unambiguous systematic
markers but that convergent evolution and
selective gene expression are common themes.
Extraction of Secondary Metabolites from
Plant : Plant secondary metabolites are currently
the subject of much research interest, but their
extraction as part of phytochemical or biological
investigations presents specific challenges that
must be addressed throughout the solvent
extraction process. Successful extraction begins
with careful selection and preparation of plant
samples. During the extraction of plant material,
it is important to minimize interference from
compounds that may coextract with the target
compounds, and to avoid contamination of the
extract, as well as to prevent decomposition of
important metabolites or artifact formation as a
result of extraction conditions or solvent
impurities. Researchers from a variety of
scientific disciplines are confronted with the
challenge of extracting plant material with
solvents, often as a first step toward isolating and
identifying the speciûc compounds responsible
for biological activities associated with a plant
or a plant extract. The impetus for this research
arises largely because plants form the foundation
of traditional pharmacopeias, and because many
of our currently important pharmaceutical drugs
are obtained from plants. Further interest arises
from the growing awareness that many of the
secondary metabolites of organisms, including
plants, serve important biological and ecological
roles, mainly as chemical messengers and
defensive compounds. Investigators engaged in
the isolation of secondary metabolites from plants
soon discover the need for considerable
laboratory finesse in the apparently routine
‘‘sample preparation’’ steps that convert crude
plant material into an extract suitable for chemical
analysis, biological testing, or chromatographic
separation.
Major Secondary Metabolite Pathways : In
plants particularly three pathways are the source
of most secondary metabolites: The shikimate
pathway, the isoprenoid pathway and the
polyketide pathway. After the formation of the
major basic skeletons, further modifications
result in plant species specific compounds. The
shikimate pathway is the major source of
aromatic compounds. It is found in
microorganisms and plants, but not in mammals,
making it an interesting target for herbicides and
antibiotics, as these compounds are expected
not to have any effect on the mammalian system.
Glyphosate is a well known example. The
Secondary Metabolites of Plants and their Role
www.IndianJournals.com
Members Copy, Not for Commercial Sale
Downloaded From IP - 117.240.114.66 on dated 11-Aug-2016
Current Trends in Biotechnology and Pharmacy
Vol. 9 (3) 293-304 July 2015, ISSN 0973-8916 (Print), 2230-7303 (Online) 299
enzymes channeling chorismate into the
aromatic amino acids pathways are chorismate
mutase and anthranilate synthase. Although, in
several plant species for both chorismate mutase
and anthranilate synthase more than one gene
has been cloned, only in case of chorismate
mutase a plastidial and a cytosolic enzyme have
been found. The phenylpropanoid pathway is one
of the most important metabolic pathways in
plants in terms of carbon flux. In a cell more than
20% of the total metabolism can go through this
pathway, the enzyme chorismate mutase is an
important regulatory point. The importance of this
pathway is due to the fact that it leads to among
others lignin, lignans, flavonoids, and
anthocyanins. Key to these products is the
enzyme phenylalanine ammonia lyase (PAL),
which converts phenylalanine into trans-cinnamic
acid by a non-oxidative deamination. This
enzyme can be found in all plants, in some plants
a single enzyme is found, whereas others may
have several iso-enzymes. The other important
pathway in plants is that of the terpenoids, also
known as isoprenoid pathway. Terpenoids include
more than one third of all known secondary
metabolites. Moreover, the C5-building block is
also incorporated in many other skeletons, e.g.
in anthraquinones, naphtoquinones,
cannabinoids, furanocoumarines, and terpenoid
indole alkaloids. In the “decoration” type of
reactions in various types of secondary
metabolites C5-units are attached to the basic
skeleton, e.g. hop bitter acids, flavonoids and
isoflavonoids.
Functions of Secondary Metabolites : Many
secondary compounds have signalling functions
influence the activities of other cells, control their
metabolic activities and co-ordinates the
development of the whole plant. Other
substances such as flower colours serve to
communicate with pollinators or protect the plants
from feeding by animals or infections by
producing specific phytoalexines after fungi
infections that inhibit the spreading of the fungi
mycelia within the plant (18). Plants use
secondary metabolites (such as volatile essential
oils and colored flavonoids or tetraterpenes) also
to attract insects for pollination or other animals
for seed dispersion, in this case secondary
metabolites serve as signal compounds.
Compounds belonging to the terpenoids,
alkaloids and flavonoids are currently used as
drugs or as dietary supplements to cure or
prevent various diseases (19) and in particular
some of these compounds seem to be efficient
in preventing and inhibiting various types of
cancer (20, 21). It has been estimated that 14-
28% of higher plant species are used medicinally
and that 74% of pharmacologically active plant
derived components were discovered after
following up on ethno-medicinal use of the plants
(22). Secondary metabolites are a metabolic
intermediates or product, found as a
differentiation product in restricted taxonomic
groups, not essential to growth and life of the
producing organism and biosynthetized from
one or more general metabolites by wider variety
of pathways than is available in general
metabolism.
Presence of volatile monoterpenes or
essential oils in the plants provides an important
defense strategy to the plants, particularly against
herbivorous insect pests and pathogenic fungi.
These volatile terpenoids also play a vital role in
plant-plant interactions and serve as attractants
for pollinators (23). They act as signalling
molecules and depict evolutionary relationship
with their functional roles. Soluble secondary
compounds such as cyanogenic glycosides
isoflavoids and alkaloids can also be toxic to
animals.
Biotechnology and Secondary Metabolites :
Since SM have evolved as compounds that are
important for the ûtness of the organisms
producing them, many of them interfere with the
pharmacological targets, which make them
interesting for several biotechnological
applications. Controlled clinical studies have
shown the efficacy of several, for example
extracts from Ginkgo biloba, Hypericum
perforatum, Piper methysticum, Chamomilla
recutita, Crataegus monogyna, Silibum
Saurabh Pagare et al
www.IndianJournals.com
Members Copy, Not for Commercial Sale
Downloaded From IP - 117.240.114.66 on dated 11-Aug-2016
marianum, Melissa ofûcinalis, Mentha piperita,
Valeriana ofûcinalis.
The use of stimulants (such as caffeine,
nicotine, ephedrine), fragrances (several
essential oils), ûavours (essential oils, capsaicin,
piperine, etc.), natural dyes, poisons (strychnine)
and hallucinogens (morphine, heroin, cocaine,
tetrahydro cannabinol) is based on SM. Since
many SM are insecticidal, fungicidal and
phytotoxic, they may be used in agriculture as
natural plant protectants. Before the advent of
synthetic pesticides about 60 years ago, plant-
derived insecticides (including nicotine, rotenone,
quassin, ryanodine, pyrethrins and azadirachtins)
were a common theme. Applications
unequivocally showed that these natural
insecticides worked. One ecological advantage
is that SM are readily degraded in plants and in
soil, is also their disadvantage and synthetic
pesticides are more resistant and persistent.
Moreover, modern pesticides are usually more
potent than biopesticides. On the other hand,
plants are easy to grow and biopesticides could
be a sustainable source of plant protectants for
farmers in countries that do not have access to
Western synthetic pesticides. Unfortunately,
legislation does not favour mixtures of
compounds to be used as pesticides; therefore,
the development of biorational pesticides has to
face many obstacles. Nevertheless, natural
compounds do provide an underexplored
alternative. As a consequence of these various
applications, a world market for plant extracts
and isolated SM exists, which exceeds 10 billion
US dollars annually. Therefore, it is a challenge
for biotechnologists to find ways to produce these
compounds in sufûcient quantity and quality.
The main and traditional way is to grow the
respective plants in the ûeld or in greenhouses
and to extract the products from them. For
several species, new varieties have been
selected with improved yields and quality. In this
context, cell and organ culture are important
techniques for in vitro propagation. In a few
instances, genetic engineering of secondary
metabolism has already had a direct inûuence
for example, when Atropa belladonna plants were
transformed with the gene that encodes the
enzymes converting L-hyoscyamine into L-
scopolamine, new plants were generated which
produced scopolamine as the major product.
More often, ûavonoid metabolism has been
altered genetically, producing plants with different
ûower colours. It is a challenge for future
research to isolate the genes of biosynthetic
pathways and to express them either in
transgenic plants or in microbes.
If successful, recombinant bacteria or
yeasts might be grown someday, which will
produce valuable plant SM. Combinatorial
biosynthesis might then be an open field. Using
genes encoding enzymes for the biosynthesis of
antibiotics, this strategy has already been
successful. It has also brought about renewed
interest in the regulation of SM synthesis and in
the location and means of sequestration of these
substances within the plant. In recent years,
attempts have been made to express the genes
of alkaloid biosynthesis in microorganisms.
Ultimately, it might be possible to produce
valuable alkaloids from recombinant bacteria or
yeast. If the corresponding SM (both from plant
or microbial origin) confers resistance to insects
or pathogens, genetic transformation of
susceptible crop plants could be another valuable
avenue for Exploitation. For more than two
decades, scientists around the world have tried
to produce valuable SM in cell or organ cultures.
Whereas undifferentiated cell cultures have often
failed to produce such a compound in reasonable
yields, differentiated organ cultures (e.g.
transformed root cultures) are often as active as
the intact plant .Cell- and tissue-speciûc gene
expression appears to control these processes.
In addresses the production of SM in vitro (Table
1).
It is possible that genetic engineering may
help to improve plant cell cultures as
biotechnological production systems in the future.
Secondary Metabolites of Plants and their Role
www.IndianJournals.com
Members Copy, Not for Commercial Sale
Downloaded From IP - 117.240.114.66 on dated 11-Aug-2016
Table1. Secondary Metabolites from Plant Cell, Tissue and Organs Cultures
Plant Name Active Ingredient Culture Type
Adhatoda vasica Vasine Shoot culture(24)
Agastache rugosa Rosmarinic acid Hairy root(25)
Ammi majus Umbelliferone Shootlet(26)
Triterpenoid Suspension(27)
Angelica gigas Deoursin Hairy root(28)
Arachis hypogaea Resveratol Hairy root(29)
Artemisia annua Artemisinin Callus(30)
Aspidosperma ramiflorum Ramiflorin Callus(31)
Azadirachta indica Azadirachtin Suspension(32)
Brucea javanica Cathin Suspension(33)
Bupleurum falcatum Saikosaponins Root(34)
Camellia chinensis Flavones Callus(35)
Capsicum annum Capsiacin Callus(36)
Cassia acutifolia Anthraquinones Suspension(37)
C. senna Anthraquinone Hairy root(38)
Catharanthus roseus Indole alkaloids Suspension(39)
Vincristine Suspension(40)
Catharathine Suspension(41)
Cayratia trifoliata Stilbenes Suspension(42)
Centella asiatica Asiaticoside Hairy root(43)
Callus(44)
Drosera rotundifolia 7-Methyljuglone Shoot culture(45)
Eleutherococcus senticosus Eleuthrosides Suspension(46)
Eriobotrya japonica Triterpenes Callus(46)
Fabiana imbricata Rutin Callus and Suspenson(47)
Fagopyrum esculentum Rutin Hairy root(48)
Fritillaria unibracteata Alkaloids Multiple shoot(49)
Gentiana macrophylla Glucoside Hairy root(50)
Gentianella austriaca Xanthone Multiple shoot(51)
Glycyrrhiza glabra Glycyrrhizin Hairy root(52)
Gymnema sylvestre Gymnemic acid Callus(53)
Hemidesmus indicus Lupeol, Rutin Shoot culture(54)
Hypericum perforatum Hypericin Multiple shoot(55)
Mentha arvensis Terpenoid Shoot(56)
Momordica charantia Flavonoid Callus(57)
Saurabh Pagare et al
www.IndianJournals.com
Members Copy, Not for Commercial Sale
Downloaded From IP - 117.240.114.66 on dated 11-Aug-2016
Conclusion
This review has dealt with a small
selection of plant secondary- metabolites and
their potential roles in defence mechanisms and
ecological adaptation, in addition to the topics
we have covered. there is an enormous range of
other compounds present in the plant kingdom,
with a very varied distribution. Plant secondary
metabolism produces products that aid in the
growth and development of plants but are not
required for the plant to survive. Secondary
metabolites have important ecological functions
in plants: They protect plants against being eaten
by herbivores and against being infected by
microbial pathogens. They serve as attractants
(odor, color, taste) for pollinators and seed-
dispersing animals. They function as agents of
plant-plant competition and plant-microbe
symbioses. The ability of plants to compete and
survive is therefore profoundly affected by the
ecological functions of their secondary
metabolites. Biotechnological approaches are
also involved in production of secondary
metabolites through genetic engineering process.
Plant tissue culture may also play a major role
for the same.
References
1. Verpoorte, R. and Alfermann, A.W. (2000)
Metabolic engineering of plant secondary
metabolism. Dordrecht, The Netherlands:
Kluwer Academic Publishers.
2. Croteau, R., Kutchan, T.M. and Lewis, N.G.
(2000) Natural Products (Secondary
metabolites).In: Buchanan BB, Gruissem w,
Jones RL, editors. Biochemistry & molecular
biology of plants.USA: Courier companies,
Inc pp 1250-1318
3. Winkel-Shirley, B. (2001). Flavonoid
Biosynthesis. A colourful Model for
Genetiecs, Biochemistry, Cell Biology and
Biotechnology. Plant Physiol. 126:485-493
4. Berli, F.J., Moreno, D., Piccolo, P.,
Hespanhol-Viana, L., Silva, M.F., Bressan-
Smith, R., Cavarnaro, J.B. and Bottini, R.
(2010). Abscisis acid is involved in the
response of grape (Vitis vinifera L.)
cv.Malbec leaf Tissues to ultraviolet-B
radiation by enhancing ultraviolet –
absorbing compounds, antioxidant enzymes
and membrane sterols. Plant cell Environ.
33(1):1-10
5. Wuyts, N., De waele, D. and Swennen, R.
(2006). Extraction and partial characteriza-
-tion of polyphenol oxidase from banana
(Musa acuminate grandr naine) roots. Plant
Physiol Biochem. 44:308-314
6. Savirnata, N.M., Jukunen-Titto, R.,
Oksanen, E. and Karjalainen, R.O. (2010).
Leaf Phenolic compounds in red clover
(Trfolium Pratense L.) induced by exposure
to moderately elevated ozone. Environ
Pollution. 158(2):440-446
7. Brooker, N., Windorski, J. and Blumi, E.
(2008) Halogenated coumarins derivatives
as novel seed protectants. Commu Agri Appl
Biolog Sci. 73(2):81-89
8. Ali, S.T., Mahmooduzzafar-Abdin, M.Z. and
Iqbal, M. (2008). Ontogenetic changes in
Folier features and psoralen content of
Psoralea corylifolia Linn. Exposed to SO2
stress. J Environ Biol. 29(5): 661-668.
9. Lake, J.A., Field, K.J., Davey, M.P., Beerling,
D.J. and Lomax, B.H. (2009) Metabolomic
and physiological responses reveal multi-
phasic acclimation of Arabidopsis thaliana
to chronic UV radiation. Plant cell Environ.
32(10):1377-1389
10. Sreevidya, V.S., Srinivasa, R.C., Rao, C.,
Sullia, S.B., Ladha, J.K. and Reddy, P.M.
(2006). Metabolic engineering of rice with
soyabean isoflavone synthase for promoting
nodulation gene expression in rhizobia. J
Exp Bot. 57(9):1957-1969
11. Posmyk MM, Kontek R, Janas KM (2009)
Antioxidant enzymes activity and phenolic
compounds content in red cabbage
seedlings exposed to copper stress.
Ecotoxicol Environ Safety. 72(2):596-602
Secondary Metabolites of Plants and their Role
www.IndianJournals.com
Members Copy, Not for Commercial Sale
Downloaded From IP - 117.240.114.66 on dated 11-Aug-2016
12. Saito, K. (2004) Sulfur assimilatory
metabolism. The long and smelling road.
Plant Physiol. 136:2443-2450
13. Grubb, C. and Abel, S. (2006) Glucosinolate
metabolism and its control. Trends Plant Sci.
11:89-100
14. Halkier, B.A. and Gershenzon, J. (2006).
Biology and biochemistry of glucosinolates.
Annual Rev Plant Biol. 57: 303-333
15. Kang, S.Y. and Kim, Y.C. (2007). Decursinol
and decursin protect primary cultured rat
cortical cells from glutamate-induced
neurotoxicity. J Pharmacy Pharmacol.
59(6):863-870
16. Leustek, T. (2002). Sulfate metabolism.
Somerville CR, Meyerowitz EM, eds, The
Arabidopsis Book. American Society of
Plant Biologists, Rockville, MD, doi/10.1199/
tab.0009
17. Lipka, U., Fuchs, R.., Kuhns, C.,
Petutschnig, E. and Lipka, V. (2010). Live
and let die-Arabidopsis non-host resistance
to powdery mildews. Eur J Cell Biol.
89(2):194-199
18. Mansfield, J.W. (2000). Antimicrobial
compounds and resistances. The role of
phytoalexins and phytoanticipins. In:
slusarenko A. J., fraser R.S.S., vanloon L.C.
and fraser R.S. (eds). Mechanism of
resisyance to plant diseases. Springer-
verlag New York., pp325-363
19. Raskin, I., Ribnicky, D.M., Komarnytsky, S.,
Ilic, N., Poulev, A., Borisjuk, N., Brinker, A.,
Moreno, D.A. and Yakoby, R..N. (2002).
Plant and human health in the twenty-first
century. Trends Biotechnol. 20:522-531
20. Watson, A.A., Fleet, G.W.J., Asano, N.,
Molyneux, R.J. and Nash, R.J. (2001).
Polyhydroxy latedalkaloid –natural
occurrence and therapeutic applications.
Phytochemistry. 56:265-295
21. Reddy, L., Odhav, B. and Bhoola, K.D.
(2003). Natural product for cancer
prevention: global perspective. Pharmacol
Theraput. 99:1-13
22. Ncube, N.S., Afolayan, A.J. and Okoh, A.I.
(2008). Assessment techniques of
antimicrobial properties of natural
compounds of plant origin: current methods
and future trends. African J Biotechnol. 7
(12):1797-1806
23. Tholl, D. (2006). Terpene Synthases and the
regulation, diversity and biological roles of
terpene metabolism. Curr Opinion Plant
Biol. 9:297-304
24. Shalaka, D.K. and Sandhya, P. (2009).
Micropropagation and organogenesis in
Adhatoda vasica for the estimation of
vasine. Pharmacog Magaz. 5:539-363
25. Lee, S.Y., Xu, H., Kim, Y.K. and Park, S.U.
(2007). Rosmarinic acid production in hairy
root cultures of Agastache rugosa Kuntze.
World J Microbiol Biotechnol. 20:969-972
26. Krolicka, A., Kartanowicz, R.,Wosinskia, S.,
Zpitter, A., Kaminski, M. and Lojkowska, E.
(2006). Induction of secondary metabolite
production in transformed callus of Ammi
majus L. grown after electromagnetic
treatment of the culture medium. Enz Microb
Technol. 39: 1386 -1389
27 Staniszewska, I., Krolicka, A., Mali, E.,
Ojkowska, E. and Szafranek, J. (2003).
Elicitation of secondary metabolites in in
vitro cultures of Ammi majus L. Enz
Microbiol Technol. 33:565-568
28. Xu, H., Kim, Y.K., Suh, S.Y., Udin, M.R.,
Lee, S.Y. and Park, S.U. (2008). Deoursin
production from hariy root culture of
Angelica gigas. J Korea Soc Appl Biol
Chem. 51:349-351
29. Kim, J.S., Lee, S.Y. and Park, S.U. (2008).
Resveratol production in hairy root culture
of peanut, Arachys hypogaea L. transformed
Saurabh Pagare et al
www.IndianJournals.com
Members Copy, Not for Commercial Sale
Downloaded From IP - 117.240.114.66 on dated 11-Aug-2016
Current Trends in Biotechnology and Pharmacy
Vol. 9 (3) 293-304 July 2015, ISSN 0973-8916 (Print), 2230-7303 (Online) 304
with differet Agrobacterium rhizogenes
strains. Afr J Biotechnol. 7:3788-3790
30. Baldi, A. and Dixit, V.K. (2008). Enhanced
artemisinin production by cell cultures of
Artemisia annua. Curr. Terends Biotechnol
Pharmacol. 2:341-348
31. Olivira, A.J.B., Koike, L., Reis, F.A.M. and
Shepherd, S.L.K. (2001). Callus culture of
Aspidosperma ramiflorum Muell.-Arg.:
growth and alkaloid production. Acta
Scientia. 23:609-612
32. Sujanya, S., Poornasri, D.B. and Sai, I.
(2008). In vitro suspension cultures of
Azadirachta indica. J Biosci. 33:113-120
33. Wagiah, M.E., Alam, G., Wiryowidagdo, S.
and Attia, K. (2008). Imporved production
of the indole alkaloid cathin-6-one from
cell suspension cultures of Brucea javanica
(L.) Merr. Ind J Sci Technol. 1:1-6
34. Kusakari, K., Yokoyama, M. and Inomata,
S. (2000) Enhanced production of
saikosaponins by root culture of Bupleurum
falcatum L. using two step control of sugar
concentration. Plant Cell Rep. 19:1115-1120
35. Nikolaeva, T.N., Zagoskina, N.V. and
Zaprometov, M.N. (2009). Production of
phenolic compounds in callus cultures of
tea plant under the effect of 2,4-D and NAA.
Russ J Pl Physiol. 56:45-49
36. Umamaheswai, A. and Lalitha, V. (2007).
In vitro effect of various growth hormones
in Capsicum annum L. on the callus
induction and production of Capsiacin. J
Plant Sci. 2:545-551
37. Nazif, N.M., Rady, M.R. and Seif, M.M.
(2000). Stimulation of anthraquinone
production in suspension cultures of Cassia
acutifolia by salt stress. Fitoterapia. 71:34-
40
38. Shrivastava, N., Patel, T. and Srivastava,
A. (2006). Biosynthetic potential of invitro
grown callus cells of Cassia senna L. var.
senna. Curr Sci. 90:1472-1473
39. Zhao, J., Zhu, W. and Hu, Q. (2001).
Enhanced catharanthine production in
Catharanthus roseus cell cultures by
combined elicitor treatment in shake flasks
and bioreactors. Enz Microb Technol.
28:673-681
40. Lee-Parsons, C.W.T. and Rogce, A.J.
(2006). Precursor limitations in methyl
jasmonate-induced Catharanthus roseus
cell cultures. Plant Cell Rep. 25:607-612
41. Ramani, S. and Jayabaskaran, C. (2008).
Enhanced catharathine and vindoline
production in suspension cultures of
Catharanthus roseus by ultraviolet-B light.
J Mol Signal. 3:9-14
42. Roat, C. and Ramawat, K.G. (2009). Elicitor
induced accumulation of stilbenes in cell
suspension cultures of Cayratia trifoliata (L.)
Domin. Plant Biotechnol Rep. 3:135-138
43. Kim, O.T., Bang, K.H., Shin, Y.S., Lee, M.J.,
Jang, S.J., Hyun, D.Y., Kim, Y.C., Senong,
N.S., Cha, S.W. and Hwang, B. (2007).
Enhanced production of asiaticoside from
hairy root cultures of Centella asitica (L.)
Urban elicited by methyl jasmonate. Plant
Cell Rep. 26:1914- 1949
44. Kiong, A.L., Mahmood, M., Fodzillan, N.M.
and Daud, S.K. (2005). Effects of precursor
supplementation on the production of
triterpenes by Centella asiatica callus
culture. Pak J BiolSci. 8:1160-1169
45. Hohtola, A., Jalonen, J., Tolnen, A., Jaakola,
L., Kamarainen, T., Pakonen, M., Karppinen,
K., Laine, K., Neubauer, P., Myllykoshi, L.,
Gyorgy, Z., Rautio, A. and Peltonen, O.
(2005), Natural product formation by
plants, enhancement, analysis, processing
and testing. In : Sustainable use renewable
natural resources – from principles to
practices (Eds. Jalkanen, A. and Nygren,
P). University of Helsinki Publication. pp. 34-
69
Secondary Metabolites of Plants and their Role
www.IndianJournals.com
Members Copy, Not for Commercial Sale
Downloaded From IP - 117.240.114.66 on dated 11-Aug-2016
Current Trends in Biotechnology and Pharmacy
Vol. 9 (3) 293-304 July 2015, ISSN 0973-8916 (Print), 2230-7303 (Online) 305
46. Shohael, A.M., Chakrabarty, D., Yu, K.W.,
Hahn, E.J. and Paek, K.Y. (2005).
Application of bioreactor system for large-
scale production of Eleutherococcus
sessiliflorus somatic embryos in an air-lift
bioreactor and production of eleutherosides.
J. Biotechnol. 120: 228-236.
47. Schmeda-Hirschmann, G., Jordan, M.,
Gertn, A., Wilken, D., Hormazabal, E. and
Tapia, A.A. (2004). Secondary metabolite
content in Fabiana imbricate plants and in
vitro cultures. Z Naturforsch. 5:48-54
48. Lee, S.Y., Cho, S.J., Park, M.H., Kim, Y.K.,
Choi, J.I. and Park. S.U. (2007). Growthand
rutin production in hairy root culture of buck
weed (Fagopyruumesculentum) Prep.
Biochem Biotechnol. 37:239-246
49. Gao, S.L., Zhu, D.N., Cai, Z.H., Jiang, Y.
and Xu, D.R. (2004). Organ culture of a
precious Chinese medicinal plant –
Fritillaria unibracteata. Plant Cell Tiss Org
Cult. 59:197- 201
50. Tiwari, K.K., Trivedi, M., Guang, Z.C., Guo,
G.Q. and Zheng, G.C. (2007). Genetic
transformation of Gentiana macrophylla with
Agrobacterium rhizogenes : growth and
production of secoiridoid glucoside
gentiopicroside in transformed hairy root
cultures. Plant Cell Rep. 26:199-210
51. Vinterhalter, B., Jankovic, T., Sovikin, L.,
Nikolic, R. and Vinterhalter, D. (2008)
Propagation and xanthone content of
Gentianella austiaca shoot cultures. Plant
Cell Tiss Org Cult. 94:329-335
52. Mehrotra, S., Kukreja, A.K., Khanuja, S.P.S.
and Mishra, B.N. (2008). Genetic
transformation studies and scale up of hairy
root culture of Glycyrrhiza glabra in
bioreactor. Elec J Biotechnol. 11:717-728
53. Gopi, C. and Vatsala, T.M. (2006). In vitro
studies on effects of plant growth regulators
on callus and suspension culture biomass
yield from Gymnema sylvestre R.Br. Afr J
Biotechnol. 5:1215-1219
54. Misra, N., Misra, P., Datta, S.K. and
Mehrotra, S. (2005). In vitro biosynthesis of
antioxidants from Hemidesmus indicus
R.Br. cultures In vitro. Dev Biol Plant.
41:285-290
55. Kornfeld, A., Kaufman, P.B., Lu, C.R.,
Gibson, D.M., Bolling, S.F., Warber, S.L.,
Chang, S.C. and Kirakosyan, A. (2007). The
production of hypericins in two selected
Hypericum perforatum shoot cultures is
related to differences in black gland culture.
Plant Physiol Biochem. 45:2432
56. Phatak, S.V. and Heble, M.R. (2002).
Organogenesis and terpenoid from plant
tissue culture.Oxford: Claredon Press, pp.
1-21.
57. Agarwal, M. and Kamal, R. (2007). Studies
on flavonoid production using invitro cultures
of Momordica charantia L. Ind J Biotechnol.
6:277-279
Saurabh Pagare et al
... These compounds positively impact human health by enhancing metabolism, boosting immunity, and improving cellular function. Additionally, they contribute to ecosystem stability by attracting pollinators and beneficial organisms, thereby aiding in the reproduction and dispersal of plants (Guerriero et al., 2018;Pagare et al., 2015). Plant secondary metabolites are also of significant industrial importance, widely used in the production of fragrances, essences, and dyes, and are favored for their biocompatibility and low toxicity . ...
... Advances in genomics and biotechnology have enabled more effective plant genetic improvement, focusing on the synthesis pathways of secondary metabolites, thus enhancing the plant's ability to produce specific secondary metabolites through genetic engineering. This not only improves the plant's disease resistance and nutritional value but also opens new avenues for the development of novel drugs (Pagare et al., 2015;Thirumurugan et al., 2018). ...
Article
Full-text available
As an efficient gene editing tool, the CRISPR/Cas9 system has been widely employed to investigate and regulate the biosynthetic pathways of active ingredients in medicinal plants. CRISPR technology holds significant potential for enhancing both the yield and quality of active ingredients in medicinal plants. By precisely regulating the expression of key enzymes and transcription factors, CRISPR technology not only deepens our understanding of secondary metabolic pathways in medicinal plants but also opens new avenues for drug development and the modernization of traditional Chinese medicine. This article introduces the principles of CRISPR technology and its efficacy in gene editing, followed by a detailed discussion of its applications in the secondary metabolism of medicinal plants. This includes an examination of the composition of active ingredients and the implementation of CRISPR strategies within metabolic pathways, as well as the influence of Cas9 protein variants and advanced CRISPR systems in the field. In addition, this article examines the long-term impact of CRISPR technology on the progress of medicinal plant research and development. It also raises existing issues in research, including off-target effects, complexity of genome structure, low transformation efficiency, and insufficient understanding of metabolic pathways. At the same time, this article puts forward some insights in order to provide new ideas for the subsequent application of CRISPR in medicinal plants. In summary, CRISPR technology presents broad application prospects in the study of secondary metabolism in medicinal plants and is poised to facilitate further advancements in biomedicine and agricultural science. As technological advancements continue and challenges are progressively addressed, CRISPR technology is expected to play an increasingly vital role in the research of active ingredients in medicinal plants.
... Secondary metabolites play crucial roles in plant defense, adaptation, and growth. In dormant buds, these metabolites (including alkaloids, flavonoids, and phenolic compounds) assist in plant survival under unfavorable environmental conditions [33]. The organization of the cytoskeleton is essential for cell morphology and division; during bud germination, cytoskeletal reorganization is necessary for the formation and expansion of new cells [34]. ...
Article
Full-text available
The walnut (Juglans regia) is an important oilseed tree species characterized by its extensive distribution, high oil yield, and nutrient-dense kernels, which provide substantial economic benefits. However, the rising incidence of late-spring frosts, exacerbated by global climate change, has adversely affected walnut yields. A comprehensive understanding of the regulatory mechanisms involved in bud dormancy, germination, and development is essential for developing strategies to mitigate the effects of late-spring frosts and for breeding frost-resistant cultivars. This study focused on W13, a protogynous walnut variety with early germination of dormant buds in spring, employing a combination of transcriptomic and hormone metabolomic analyses. Our results emphasized four key biological processes—cellular response to ethylene stimulus, phenylpropanoid metabolic process, ethylene-activated signaling pathway, and monooxygenase activity—along with several relevant pathways, including plant hormone signal transduction, flavone and flavonol biosynthesis, biosynthesis of secondary metabolites, and MAPK signaling pathway, all crucial for walnut bud germination. Additionally, bud germination is closely associated with alterations in various hormone signaling pathways, including abscisic acid, auxin, cytokinin, ethylene, gibberellins, jasmonic acid, and salicylic acid. By assessing hormone levels and gene expression at different developmental stages, we pinpointed potential regulatory genes and critical hormones associated with bud germination. Furthermore, through weighted correlation network analysis, we constructed a co-expression network, identifying gene modules specifically expressed during dormancy, germination, budding, and leafing phases. The hub genes within these modules are likely pivotal in regulating walnut bud germination. Our analysis also revealed that genes from various transcription factor families are central within the co-expression network, indicating their significant roles in the bud germination process. Correlation network analysis of hormone and gene further illuminated the mechanisms through which genes and hormones jointly influence walnut bud germination. These findings establish a crucial molecular basis for a more comprehensive understanding of the mechanisms governing germination and development in dormant walnut buds.
... While many species have traditional applications as spices or ornamentals, they are also valued as herbal medicine [2]. The therapeutic properties of numerous members of this family are largely attributed to their abundant bioactive compounds [4,5], such as terpenes, terpenoids, and flavonoids [6][7][8]. In the plant, some of these compounds serve to deter herbivores, combat microbial infections, or protect against solar radiation, while others attract pollinators through color or scent [6,7,9]. ...
Article
Full-text available
Hornstedtia scyphifera ( J.Koenig) Steud. represents a lesser-known member of the ginger family (Zingiberaceae) that is used in Malaysia as spice and traditional medicine. The phytochemical investigation of leaves from this species utilizing diverse analytical methods has provided comprehensive insights into its chemical profile for the first time. Headspace gas chromatography-mass spectrometry (HS-GCMS) and GCMS analyses of essential oil and nonpolar extracts verified α -pinene, camphene, p -cymene, and camphor as main volatile compounds. Metabolite profiling of the crude extract by ultra-high-performance-liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS) unveiled terpenoids, flavonoids and other phenolics as major compound classes. Isolation and follow-up structure elucidation, involving 1D and 2D NMR, HRMS, UV and CD analysis, yielded two new sesquiterpenoids, (1 R ,5 S ,6 S ,7 R ,10 R )-mustak-14-oic acid ( 1 ) and (1 R ,6 S ,7 S ,10 R )-6-hydroxy-anhuienosol ( 2 ), along with 24 known compounds (seven terpenoids, seven flavonoids, ten phenolics), 21 of these never reported for H. scyphifera . Additionally, the crude extract and fractions from the purification process were screened for antibacterial and antifungal activity. This is supplemented by an extensive literature research for described bioactivities of all isolated compounds. Our results support and explain previously detected antimicrobial, antifungal and neuroprotective effects of H. scyphifera extracts and provide evidence for its potential pharmacological importance.
Article
Full-text available
The hybridization phenomenon increases genetic diversity and modifies recombinant individuals’ secondary metabolite (SMs) content, affecting the canopy-dependent community. Hybridization events occur when Quercus rugosa and Q. glabrescens oaks converge in sympatry. Here, we analyzed the effect of the genetic diversity (He) and SMs of Q. rugosa, Q. glabrescens and hybrids on the community of gall-inducing wasps (Cynipidae) and their parasitoids on 100 oak canopy trees in two allopatric and two hybrid zones. Eighteen gall wasp species belonging to six genera and six parasitoid genera contained in four families were identified. The most representative parasitoid genera belonged to the Chalcidoidea family. Abundance, infestation levels and richness of gall wasps and their parasitoids registered the next pattern: Q. rugosa higher than the hybrids, and the hybrids equal to Q. glabrescens. Oak host genetic diversity was the variable with the highest influence on the quantitative SMs expression, richness and abundance of gall wasps and their parasitoids. The influence of SMs on gall wasps and their parasitoids showed the next pattern: scopoletin > quercitrin > rutin = caffeic acid = quercetin glucoside. Our findings indicate that genetic diversity may be a key factor influencing the dynamics of tri-trophic interactions that involve oaks.
Article
Full-text available
Haworthia truncata, a species native to South Africa, is characterized by its limited growth and scarcity, contributing to high production costs. Countries like China and Turkey are known for exporting Haworthia globally. Tissue culture offers an efficient method for mass-producing unique and beautiful species such as H. truncata. This study tested Murashige and Skoog (MS) basal media supplemented with various concentrations of IBA (0.05–1.5 mg/L), NAA (0.05–0.25 mg/L), and BA (0.25–1.5 mg/L) to promote shoot proliferation. MS medium without plant growth regulators (PGRs) was also tested as a control. Different explant types (leaf, root, and inflorescence) were analyzed for their potential in direct and indirect regeneration. Inflorescence explants showed the highest callus induction with 1.5 mg/L IBA, while optimal shoot proliferation occurred at 1 mg/L IBA. Callus induction was optimal for leaf explants with 0.05 mg/L NAA and 0.25 mg/L BA, and shoot proliferation was highest at 0.05 mg/L NAA and 1 mg/L BA. Root explants achieved maximum callus induction with 0.25 mg/L BA and 0.25 mg/L NAA, with the best shoot proliferation using 0.05 mg/L NAA and 1 mg/L BA. The highest rooting percentage of regenerated shoots was obtained on ½ MS medium with 1.5 mg/L IBA.
Article
Full-text available
Rhizophoramucronata Lam., a plant with a rich history of traditional use in various cultures, was subjected to chemical investigation, resulting in the isolation of five terpenoids and derivatives. The structures of these compounds, namely, 1,1,5,7-tetramethyl-4,5-dihydroacenaphthylen-3(1H)-one (1), 3β-hydroxy-11-oxo-olean-12 enyl palmitate (2), taraxerol (3), 3-(Z)-coumaroyltaraxerol (4), and 3β-(E)-coumaroyltaraxerol (5), were elucidated through extensive NMR spectroscopic analysis like ¹H NMR, ¹³C NMR, COSY, HSQC, and HMBC, as well as comparison with those of similar compounds described in the literature. These phytochemicals were subjected to computational assessment through molecular docking against superoxide dismutase (SOD), glutathione peroxidase (GPX), catalase (CAT), cyclooxygenase-2 (COX-2), epidermal growth factor receptor (EGFR), and cyclin-dependent kinase 2 (CDK-2), in addition to ADME/T analyses. Molecular dynamics (MD) simulation was conducted for the compounds showing highest binding affinity toward respective receptor. Different fractions of the crude methanol (MeOH) extract were evaluated for their antioxidant, cytotoxicity, thrombolytic, and anti-inflammatory activities. The ethyl acetate soluble fraction (RME) exhibited the highest DPPH free radical scavenging activity, with an IC50 value of 1.73 μg/mL, compared to the standard (1.68 μg/mL). In the brine shrimp lethality cytotoxicity, the chloroform soluble fraction (RMC) and RME demonstrated substantial lethality, with LC50 values of 0.95 and 1.17 μg/mL, respectively, in comparison to the standard (0.35 μg/mL). Furthermore, the petroleum ether soluble fraction (RMP) and RME displayed substantial activity in the thrombolytic assay, with 86.12% and 73.12% clot lysis, respectively (p<0.001), compared to the standard (97.11%). In the membrane stabilizing assay, the RMC and RME exhibited significant inhibition of hypotonic solution and heat-induced hemolysis. The isolated compounds demonstrated impressive binding scores when interacting with SOD, GPX, CAT, and EGFR receptors. However, their performance was notably lacking when it came to binding with COX-2 and CDK-2 receptors.
Chapter
Electrochemical redox reactions are fundamental processes involving electron transfer that occur at the interface between electrodes and electrolytes, playing a crucial role in various scientific fields. This chapter explores the significance of these reactions, particularly in the context of electrochemical sensors, and discusses their applications in chemistry, materials science, and energy conversion. Various electrochemical techniques, such as cyclic voltammetry and chronoamperometry, are introduced to analyze redox reactions and develop practical applications. The study of bioactive molecules in electrochemistry is of paramount importance, given its wide-ranging applications. These molecules, including neurotransmitters, antioxidants, metabolites, and biomarkers, are pivotal in biological processes, healthcare, disease diagnosis, and environmental monitoring. Understanding the electrochemical behavior of bioactive molecules enables the development of diagnostic tools, neuroscience research, antioxidant assessment, metabolism monitoring, environmental protection, and food safety. Furthermore, it contributes to drug development and biotechnology applications, underscoring its interdisciplinary significance. Mechanically alloyed modifiers play a crucial role in enhancing the electrochemical performance of materials and electrodes. Mechanical alloying, a process involving powder milling and blending, creates alloyed or composite materials with improved properties. These modifiers enhance conductivity, increase surface area, catalyze reactions, improve stability, and enable selective sensing. They find applications in energy storage, environmental sensing, biomedical devices, and more, making them invaluable for tailoring electrode materials and advancing electrochemical systems. This chapter sheds light on the importance of understanding electrochemical redox reactions, especially concerning bioactive molecules, and highlights the role of mechanically alloyed modifiers in advancing sensor technology and a diverse range of applications. It underscores the interdisciplinary nature of electrochemistry and its pivotal role in addressing critical challenges in healthcare, environmental protection, and materials science.
Article
Full-text available
Biofilms are bacterial communities on surfaces within an extracellular matrix. Targeting biofilm-specific bacteria is crucial, and natural compounds with reported antibiofilm activity have garnered significant interest. The study evaluated the antibacterial and antibiofilm activity of Erythrina senegalensis leaf extract against multidrug-resistant (MDR) Gram-negative bacteria, including S. Typhimurium, S. Typhi, S. Enteritidis, Klebsiella pneumoniae, and Pseudomonas aeruginosa. The leaf extract was prepared using aqueous and ethanol solvents, and qualitative phytochemical screening revealed the presence of various bioactive compounds such as tannins, saponins, cardiac glycosides, flavonoids, terpenoids, alkaloids, anthraquinone, reducing sugar, and ketones. A Kirby–Bauer disc diffusion assay was performed to test the susceptibility of antibiotics, and the antibacterial efficacy of the aqueous and ethanol extracts of E. senegalensis was determined using the cup-plate method, while the antibiofilm activities were determined using the crystal violet titer-plate method. The aqueous and ethanol extracts of E. senegalensis revealed the presence of tannins, saponins, cardiac glycosides, flavonoids, terpenoids, alkaloids, anthraquinone, reducing sugar, and ketones. The study found that the Gram-negative bacteria isolates that were MDR were S. Typhimurium, S. Enteritidis, and P. aeruginosa, while K. pneumoniae was resistant to beta-lactam and fluoroquinolones, and S. Typhi was susceptible to all antibiotics tested. Statistically, susceptibility to antibiotics had an inverse, weak, and significant relationship with biofilm production (r = −0.453, −0.106, −0.124, −0.106, −0.018, n = 10, p < 0.05). The aqueous extract showed good biofilm inhibition against K. pneumoniae and P. aeruginosa, and poor biofilm inhibition against S. Enteritidis, while S. Typhimurium and S. Typhi exhibited no biofilm inhibition. The ethanol extract did not demonstrate any antibiofilm activity against the tested Gram-negative pathogens. The study suggests that the Gram-negative bacteria’s capacity to form biofilms is negatively associated with their antibiotic resistance phenotypes, and the aqueous extract of E. senegalensis exhibited moderate antibiofilm activity against K. pneumoniae, P. aeruginosa, and S. Enteritidis.
Article
Full-text available
Callus cultures were initiated from nodal segments and leaf explants of Gymnema sylvestre on Murashige and Skoog (1962) medium containing basic salts and 30 g/l sucrose supplemented with different concentrations (0.10, 0.25, 0.5, 1.0, 2.0 and 5.0 mg/l) of 2,4-dichlorophenoxy acetic acid (2,4-D), α-naphthalene acetic acid (NAA), indole-3-acetic acid (IAA), indole-3-butyric acid (IBA), kinetin (KN) and 6-benzyladenine (BA). Callus induction was observed in 0.5 mg/l of 2, 4-D supplemented medium for both explants. At the initial stage, some parts of explants enlarged and gave raise to pale yellowish calli after 2-3 weeks of incubation. The harvested cell biomass was subjected to extraction of active principles. In this study, cell biomass extracts were compared with extracts from leaves of naturally growing gymnema plants. HPLC analysis of these extracts showed that the main components of the active principles namely gymnemic acids and gymnemagenin were present in sufficiently large amounts in the cultured undifferentiated cells.
Article
Full-text available
Callus cultures and in vitro plant development of Momordica charantia L. were establishment on Murashige and Skoog's (MS) medium using different concentrations and combinations of auxins and cytokinins. Further, qualitative and quantitative production of flavonoids in callus cultures and different in vitro developmental stages were studied by using thin layer chromatography and spectrophotometric analysis. Presence of three flavonoids was detected and the maximum amount of total flavonoid content was observed in 6-wkold callus cultures (2.90 mg/g dry wt). While in different in vitro morphogenetic stages, the maximum amount of total flavonoid content was observed in multiple shoots (2.96 mg/g dry wt).
Article
Full-text available
In an attempt to increase the productivity of the pharmaceutical compound canthin-6-one from cell suspension culture of Brucea javanica, a high cell density culture and improved culture conditions have been investigated. Various culture conditions and culture stage of growth, especially addition of tryptophan as a stimulant on the production of canthin-6-one were of particular interest in this study. The highest yield of canthin-6-one, 26.72 mg g-l dry cell, was produced intracellular in 50 g L-1 cell mass. The established cell suspensions were harvested at the age of 40 days and placed into MS medium containing 1.0 mg L-1 2,4-D, 1.0 mg L-1 NAA and 0.1 mg L-1 Kinetin and 10 mg L-1 tryptophan for 33-40 days, approximately when the cultures were at their late stationary phase of growth. Addition of 20 mg L-1 tryptophan did not show a significant difference in canthin-6-one production (p>0.05). Higher than 10 mg L-1 of tryptophan showed adverse effect on the concentration of canthin-6-one alkaloid (p=0.01). Qualitative analysis of chloroform-extracts of dried cells from suspension cultures revealed spots on TLC; and the identity of canthin-6-one was established by comparison of its Rf value (Rf=0.37), its colour reaction with Dragendorff reagent and ammonium sulphate and its behaviour in UV with an authentic sample. Quantification of canthin-6-one alkaloid using TLC-densitometry scanner in response to different concentration of tryptophan as a precursor showed a concentration-dependent response. The production of canthin-6-one at 26.72 mg g-1 dried cell weight in this study, establishes a methodology of an improved procedure compared to those previously reported and offers an opportunity for production of canthin-6-one alkaloid at an industrial level. Keywords: Canthin-6-One, cell Suspension, Brucea javanica, secondary metabolites.
Book
Plant secondary metabolism is an economically important source of fine chemicals, such as drugs, insecticides, dyes, flavours, and fragrances. Moreover, important traits of plants such as taste, flavour, smell, colour, or resistance against pests and diseases are also related to secondary metabolites. The genetic modification of plants is feasible nowadays. What does the possibility of engineering plant secondary metabolite pathways mean? In this book, firstly a general introduction is given on plant secondary metabolism, followed by an overview of the possible approaches that could be used to alter secondary metabolite pathways. In a series of chapters from various authorities in the field, an overview is given of the state of the art for important groups of secondary metabolites. No books have been published on this topic so far. This book will thus be a unique source of information for all those involved with plants as chemical factories of fine chemicals and those involved with the quality of food and ornamental plants. It will be useful in teaching graduate courses in the field of metabolic engineering in plants.
Article
Medicinal plants have recently received the attention of the pharmaceutical and scientific communities and various publications have documented the therapeutic value of natural compounds in a bid to validate claims of their biological activity. Attention has been drawn to the antimicrobial activity of plants and their metabolites due to the challenge of growing incidences of drug-resistant pathogens. Some plants have shown the ability to overcome resistance in some organisms and this has led to researchers’ investigating their mechanisms of action and isolating active compounds. Particular focus is on establishing the effect of the plant(s) extracts in terms of their microstatic and microcidal action and the spectrum of organisms affected. This has enabled exploitation of plants for the treatment of microbial infections and in the development of new antimicrobial agents. This requires rigorous research and it is therefore imperative to follow standard methods to authenticate claims of antimicrobial action. Results comparability is largely dependent on the techniques employed in the investigations and conclusive results can only be obtained if methods are standardized and universal. This paper reviews the current methods used in the investigations of the efficacy of plants as antimicrobial agents and points out some of the differences in techniques employed by different authors.
Article
The present study was aimed to develop a novel protocol for the in vitro induction of callus for the production of capsaicin from Capsicum annuum L. For callus production young leaves, growing shoots, nodal region from the sterile germinated seedlings and placental regions and pericarp tissue from the fruit pods were used as explants. They were cultured on MS Medium supplemented with the various combinations of GA, IAA, NAA, 2, 4-D and Kin. Of all tried combinations of growth hormones, MS Medium with 2.0 mg L-1 2, 4-D and 0.5 mg L-1 Kin was producing significant callus induction and proliferation in placental explants. The placental callus extract was taken for the estimation of capsaicin by colorimetric method. Extract had 1.6 mg -1 of capsaicin g-1 fresh weight of the callus. This could be an efficient protocol for capsaicin production from the placental calli and used for the large scale commercial production of capsaicin.
Article
Five different strains of Agrobacterium rhizogenes differed in their ability to induce peanut (Arachis hypogaea L.) hairy roots and also showed varying effects on the growth and resveratrol production in hairy root cultures. A. rhizogenes R1601 is the most effective strain for the induction (75.8%), growth (7.6 g/l) and resveratrol production (1.5 mg/g) in hairy root of peanut. Our results demonstrate that the use of suitable strains of A. rhizogenes may allow study of the regulation of resveratrol biosynthesis in hairy root cultures of A. hypogaea.