Problems Associated with the Efficacy, Stability and Quality Control of Herbal Drugs
Preparations
The number of reports of patients experiencing negative health consequences
caused by the use of herbal medicines has increased in recent years [36]. Analysis
and studies have revealed a variety of reasons for such problems. One of the major
causes of reported adverse events is directly linked to the poor quality of herbal
medicines, including raw medicinal plant materials. It has therefore been recog-
nized that insufficient attention has been paid to the quality assurance and control
of herbal medicines [37].
1.4 Problems Associated with the Efficacy, Stability and Quality Control of Herbal Drugs Preparations 13
Quality control directly impacts the safety and efficacy of herbal medicinal prod-
ucts [38]. The implementation of good agricultural and collection practises for me-
dicinal plants is only the first step in quality assurance, on which the safety and ef-
ficacy of herbal medicinal products directly depend, and also plays an important
role in the protection of natural resources of medicinal plants for sustainable use.
Some reported adverse events following the use of certain herbal medicines have
been associated with a variety of possible explanations, including the inadvertent
use of the wrong plant species, adulteration with undeclared other medicines
and/or potent substances, contamination with undeclared toxic and/or hazardous
substances, overdosage, inappropriate use by health care providers or consumers,
and interactions with other medicines, resulting in adverse drug effects [39].
The safety and quality of raw medicinal plant materials and finished products de-
pend on factors that may be classified as intrinsic (genetic) or extrinsic (environ-
ment, collection methods, cultivation, harvest, post-harvest processing, transport,
and storage practises). Inadvertent contamination by microbial or chemical agents
during any of the production stages can also lead to deterioration in safety and
quality. Medicinal plants collected from the wild population may be contaminated
by other species or plant parts through misidentification, accidental contamina-
tion, or intentional adulteration, all of which may have unsafe consequences.
The collection of medicinal plants from wild populations can give rise to addi-
tional concerns related to global, regional, and/or local over-harvesting, and protec-
tion of endangered species. The impact of cultivation and collection on the envi-
ronment and ecological processes, and the welfare of local communities should be
considered [40].
It is well established that intrinsic and extrinsic factors, including species differ-
ences, organ specificity, diurnal and seasonal variation, environment, field collec-
tion and cultivation methods, contamination, substitution, adulteration, and pro-
cessing and manufacturing practises greatly affect botanical quality. Intrinsically,
botanicals are derived from dynamic living organisms, each of which is capable of
being slightly different in its physical and chemical characters due to genetic influ-
ence.
Diurnal and seasonal variations are other intrinsic factors affecting chemical ac-
cumulation in both wild and cultivated plants. Depending on the plant, the accu-
mulation of chemical constituents can occur at any time during the various stages
of growth. In the majority of cases, maximum chemical accumulation occurs at the
time of flowering, followed by a decline beginning at the fruiting stage. The time
of harvest or field collection can thus influence the quality of the final herbal prod-
uct. There are many extrinsic factors affecting the qualities of medicinal plants. It
has been well established that factors such as soil, light, water, temperature, and
nutrients can, and do, affect phytochemical accumulation in plants,
The methods employed in field collection from the wild, as well as in commer-
cial cultivation, harvest, post-harvest processing, shipping, and storage can also in-
fluence the physical appearance and chemical quality of botanical source materials.
Contamination by microbial and chemical agents (pesticides, herbicides, heavy
metals), as well as by insect, animal, animal parts, and animal excreta during any
14 1 Bioactive Phytocompounds: New Approaches in the Phytosciences
of the stages of source plant material production can lead to lower quality and/or
unsafe materials. Adulteration of herbal medicines with synthetic drugs represents
another problem in product quality.
In the following paragraphs technical aspects of medicinal plant production will
be discussed. According to the World health Organization [37] the botanical iden-
tity, scientific name (genus, species, subspecies/variety, author, and family) of
each medicinal plant under cultivation should be verified and recorded. If avail-
able, the local and English common names should also be recorded. Other relevant
information, such as the cultivar name, ecotype, chemotype, or phenotype, may al-
so be provided, as appropriate. For commercially available cultivars, the name of
the cultivar and of the supplier should be provided. It’s essential that a voucher bo-
tanical specimen used in the experiments be placed in a regional or national her-
barium for identification and further consultation by other researchers; it is almost
impossible and not advised to publish without the registration numbers.
Cultivation of medicinal plants requires intensive care and management. The
conditions and duration of cultivation required vary depending on the quality of
the medicinal plant materials required. If no scientific published or documented
cultivation data are available, traditional methods of cultivation should be followed,
where feasible. Otherwise a method should be developed through research. The
principles of good plant husbandry, including appropriate rotation of plants select-
ed according to environmental suitability, should be followed, and tillage should be
adapted to plant growth and other requirements. Risks of contamination as a result
of pollution of the soil, air, or water by hazardous chemicals should be avoided.
The impact of past land uses on the cultivation site, including the planting of pre-
vious crops and any applications of plant protection products should be evaluated.
The quality and growth of medicinal plants can also be affected by other plants,
other living organisms, and by human activities. The introduction of nonindige-
nous medicinal plant species into cultivation may have a detrimental impact on the
biological and ecological balance of the region. The ecological impact of cultivation
activities should be monitored over time, where practical.
The social impact of cultivation on local communities should also be examined
to ensure that negative impacts on local livelihood are avoided. In terms of local in-
come-earning opportunities, small-scale cultivation is often preferable to large-
scale production, especially if small-scale farmers are organized to market their
products jointly. If large-scale medicinal plant cultivation is or has been estab-
lished, care should be taken that local communities benefit directly from, for exam-
ple, fair wages, equal employment opportunities, and capital reinvestment.
Climatic conditions, for example, length of day, rainfall (water supply), and field
temperature, significantly influence the physical, chemical, and biological qualities
of medicinal plants. The duration of sunlight, average rainfall, average tempera-
ture, including daytime and night-time temperature differences, also influence the
physiological and biochemical activities of plants, and prior knowledge should be
considered.
The soil should contain appropriate amounts of nutrients, organic matter, and
other elements to ensure optimal medicinal plant growth and quality. Optimal soil
1.4 Problems Associated with the Efficacy, Stability and Quality Control of Herbal Drugs Preparations 15
conditions, including soil type, drainage, moisture retention, fertility, and pH, will
be dictated by the selected medicinal plant species and/or target medicinal plant
part. The use of fertilizers is often necessary in order to obtain large yields of me-
dicinal plants. It is, however, necessary to ensure that correct types and quantities
of fertilizers are used through agricultural research. In practise, organic and chem-
ical fertilizers are used.
Human excreta must not be used as a fertilizer owing to the potential presence
of infectious microorganisms or parasites. Animal manure should be thoroughly
composted to meet safe sanitary standards of acceptable microbial limits and to de-
stroy the germination capacity of weeds. Any applications of animal manure
should be documented. Chemical fertilizers that have been approved by the coun-
tries of cultivation and consumption should be used. All fertilizing agents should
be applied sparingly and in accordance with the needs of the particular medicinal
plant species and supporting capacity of the soil. Fertilizers should be applied in
such a manner as to minimize leaching.
Any agrochemical used to promote the growth of or to protect medicinal plants
should be kept to a minimum, and applied only when no alternative measures are
available. Integrated pest management should be followed where appropriate.
When necessary, only approved pesticides and herbicides should be applied at the
minimum effective level, in accordance with the labeling and/or package insert in-
structions of the individual product and the regulatory requirements that apply for
the grower and the end-user countries. Only qualified staff using approved equip-
ment should carry out pesticide and herbicide applications. Growers and produc-
ers should comply with maximum pesticide and herbicide residue limits, as stipu-
lated by local, regional and/or national regulatory authorities.
Medicinal plants should be harvested during the optimal season or time period
to ensure the production of medicinal plant materials and finished herbal products
of the best possible quality. The time of harvest depends on the plant part to be
used. It is well known that the concentration of biologically active constituents var-
ies with the stage of plant growth and development. This also applies to nontarget-
ed toxic or poisonous indigenous plant ingredients. The best time for harvest
(quality peak season/time of day) should be determined according to the quality
and quantity of bioactive phytocompounds rather than the total vegetative yield of
the targeted medicinal plant parts. During harvest, care should be taken to ensure
that no foreign matter, weeds, or toxic plants are mixed with the harvested medic-
inal plant materials. Medicinal plants should be harvested under the best possible
conditions, avoiding dew, rain, or exceptionally high humidity. If harvesting occurs
in wet conditions, the harvested material should be transported immediately to an
indoor drying facility to expedite drying so as to prevent any possible deleterious ef-
fects due to increased moisture levels, which promote microbial fermentation and
mold. Cutting devices, harvesters, and other machines should be kept clean and
adjusted to reduce damage and contamination from soil and other materials. They
should be stored in an uncontaminated, dry place or facility free from insects, ro-
dents, birds and other pests, and inaccessible to livestock and domestic animals.
16 1 Bioactive Phytocompounds: New Approaches in the Phytosciences
Contact with soil should be avoided as far as possible so as to minimize the mi-
crobial load of harvested medicinal plant materials. The harvested raw materials
should be transported promptly in clean, dry conditions. They may be placed in
clean baskets, dry sacks, trailers, hoppers, or other well-aerated containers and car-
ried to a central point for transport to the processing facility.
Preparations
The number of reports of patients experiencing negative health consequences
caused by the use of herbal medicines has increased in recent years [36]. Analysis
and studies have revealed a variety of reasons for such problems. One of the major
causes of reported adverse events is directly linked to the poor quality of herbal
medicines, including raw medicinal plant materials. It has therefore been recog-
nized that insufficient attention has been paid to the quality assurance and control
of herbal medicines [37].
1.4 Problems Associated with the Efficacy, Stability and Quality Control of Herbal Drugs Preparations 13
Quality control directly impacts the safety and efficacy of herbal medicinal prod-
ucts [38]. The implementation of good agricultural and collection practises for me-
dicinal plants is only the first step in quality assurance, on which the safety and ef-
ficacy of herbal medicinal products directly depend, and also plays an important
role in the protection of natural resources of medicinal plants for sustainable use.
Some reported adverse events following the use of certain herbal medicines have
been associated with a variety of possible explanations, including the inadvertent
use of the wrong plant species, adulteration with undeclared other medicines
and/or potent substances, contamination with undeclared toxic and/or hazardous
substances, overdosage, inappropriate use by health care providers or consumers,
and interactions with other medicines, resulting in adverse drug effects [39].
The safety and quality of raw medicinal plant materials and finished products de-
pend on factors that may be classified as intrinsic (genetic) or extrinsic (environ-
ment, collection methods, cultivation, harvest, post-harvest processing, transport,
and storage practises). Inadvertent contamination by microbial or chemical agents
during any of the production stages can also lead to deterioration in safety and
quality. Medicinal plants collected from the wild population may be contaminated
by other species or plant parts through misidentification, accidental contamina-
tion, or intentional adulteration, all of which may have unsafe consequences.
The collection of medicinal plants from wild populations can give rise to addi-
tional concerns related to global, regional, and/or local over-harvesting, and protec-
tion of endangered species. The impact of cultivation and collection on the envi-
ronment and ecological processes, and the welfare of local communities should be
considered [40].
It is well established that intrinsic and extrinsic factors, including species differ-
ences, organ specificity, diurnal and seasonal variation, environment, field collec-
tion and cultivation methods, contamination, substitution, adulteration, and pro-
cessing and manufacturing practises greatly affect botanical quality. Intrinsically,
botanicals are derived from dynamic living organisms, each of which is capable of
being slightly different in its physical and chemical characters due to genetic influ-
ence.
Diurnal and seasonal variations are other intrinsic factors affecting chemical ac-
cumulation in both wild and cultivated plants. Depending on the plant, the accu-
mulation of chemical constituents can occur at any time during the various stages
of growth. In the majority of cases, maximum chemical accumulation occurs at the
time of flowering, followed by a decline beginning at the fruiting stage. The time
of harvest or field collection can thus influence the quality of the final herbal prod-
uct. There are many extrinsic factors affecting the qualities of medicinal plants. It
has been well established that factors such as soil, light, water, temperature, and
nutrients can, and do, affect phytochemical accumulation in plants,
The methods employed in field collection from the wild, as well as in commer-
cial cultivation, harvest, post-harvest processing, shipping, and storage can also in-
fluence the physical appearance and chemical quality of botanical source materials.
Contamination by microbial and chemical agents (pesticides, herbicides, heavy
metals), as well as by insect, animal, animal parts, and animal excreta during any
14 1 Bioactive Phytocompounds: New Approaches in the Phytosciences
of the stages of source plant material production can lead to lower quality and/or
unsafe materials. Adulteration of herbal medicines with synthetic drugs represents
another problem in product quality.
In the following paragraphs technical aspects of medicinal plant production will
be discussed. According to the World health Organization [37] the botanical iden-
tity, scientific name (genus, species, subspecies/variety, author, and family) of
each medicinal plant under cultivation should be verified and recorded. If avail-
able, the local and English common names should also be recorded. Other relevant
information, such as the cultivar name, ecotype, chemotype, or phenotype, may al-
so be provided, as appropriate. For commercially available cultivars, the name of
the cultivar and of the supplier should be provided. It’s essential that a voucher bo-
tanical specimen used in the experiments be placed in a regional or national her-
barium for identification and further consultation by other researchers; it is almost
impossible and not advised to publish without the registration numbers.
Cultivation of medicinal plants requires intensive care and management. The
conditions and duration of cultivation required vary depending on the quality of
the medicinal plant materials required. If no scientific published or documented
cultivation data are available, traditional methods of cultivation should be followed,
where feasible. Otherwise a method should be developed through research. The
principles of good plant husbandry, including appropriate rotation of plants select-
ed according to environmental suitability, should be followed, and tillage should be
adapted to plant growth and other requirements. Risks of contamination as a result
of pollution of the soil, air, or water by hazardous chemicals should be avoided.
The impact of past land uses on the cultivation site, including the planting of pre-
vious crops and any applications of plant protection products should be evaluated.
The quality and growth of medicinal plants can also be affected by other plants,
other living organisms, and by human activities. The introduction of nonindige-
nous medicinal plant species into cultivation may have a detrimental impact on the
biological and ecological balance of the region. The ecological impact of cultivation
activities should be monitored over time, where practical.
The social impact of cultivation on local communities should also be examined
to ensure that negative impacts on local livelihood are avoided. In terms of local in-
come-earning opportunities, small-scale cultivation is often preferable to large-
scale production, especially if small-scale farmers are organized to market their
products jointly. If large-scale medicinal plant cultivation is or has been estab-
lished, care should be taken that local communities benefit directly from, for exam-
ple, fair wages, equal employment opportunities, and capital reinvestment.
Climatic conditions, for example, length of day, rainfall (water supply), and field
temperature, significantly influence the physical, chemical, and biological qualities
of medicinal plants. The duration of sunlight, average rainfall, average tempera-
ture, including daytime and night-time temperature differences, also influence the
physiological and biochemical activities of plants, and prior knowledge should be
considered.
The soil should contain appropriate amounts of nutrients, organic matter, and
other elements to ensure optimal medicinal plant growth and quality. Optimal soil
1.4 Problems Associated with the Efficacy, Stability and Quality Control of Herbal Drugs Preparations 15
conditions, including soil type, drainage, moisture retention, fertility, and pH, will
be dictated by the selected medicinal plant species and/or target medicinal plant
part. The use of fertilizers is often necessary in order to obtain large yields of me-
dicinal plants. It is, however, necessary to ensure that correct types and quantities
of fertilizers are used through agricultural research. In practise, organic and chem-
ical fertilizers are used.
Human excreta must not be used as a fertilizer owing to the potential presence
of infectious microorganisms or parasites. Animal manure should be thoroughly
composted to meet safe sanitary standards of acceptable microbial limits and to de-
stroy the germination capacity of weeds. Any applications of animal manure
should be documented. Chemical fertilizers that have been approved by the coun-
tries of cultivation and consumption should be used. All fertilizing agents should
be applied sparingly and in accordance with the needs of the particular medicinal
plant species and supporting capacity of the soil. Fertilizers should be applied in
such a manner as to minimize leaching.
Any agrochemical used to promote the growth of or to protect medicinal plants
should be kept to a minimum, and applied only when no alternative measures are
available. Integrated pest management should be followed where appropriate.
When necessary, only approved pesticides and herbicides should be applied at the
minimum effective level, in accordance with the labeling and/or package insert in-
structions of the individual product and the regulatory requirements that apply for
the grower and the end-user countries. Only qualified staff using approved equip-
ment should carry out pesticide and herbicide applications. Growers and produc-
ers should comply with maximum pesticide and herbicide residue limits, as stipu-
lated by local, regional and/or national regulatory authorities.
Medicinal plants should be harvested during the optimal season or time period
to ensure the production of medicinal plant materials and finished herbal products
of the best possible quality. The time of harvest depends on the plant part to be
used. It is well known that the concentration of biologically active constituents var-
ies with the stage of plant growth and development. This also applies to nontarget-
ed toxic or poisonous indigenous plant ingredients. The best time for harvest
(quality peak season/time of day) should be determined according to the quality
and quantity of bioactive phytocompounds rather than the total vegetative yield of
the targeted medicinal plant parts. During harvest, care should be taken to ensure
that no foreign matter, weeds, or toxic plants are mixed with the harvested medic-
inal plant materials. Medicinal plants should be harvested under the best possible
conditions, avoiding dew, rain, or exceptionally high humidity. If harvesting occurs
in wet conditions, the harvested material should be transported immediately to an
indoor drying facility to expedite drying so as to prevent any possible deleterious ef-
fects due to increased moisture levels, which promote microbial fermentation and
mold. Cutting devices, harvesters, and other machines should be kept clean and
adjusted to reduce damage and contamination from soil and other materials. They
should be stored in an uncontaminated, dry place or facility free from insects, ro-
dents, birds and other pests, and inaccessible to livestock and domestic animals.
16 1 Bioactive Phytocompounds: New Approaches in the Phytosciences
Contact with soil should be avoided as far as possible so as to minimize the mi-
crobial load of harvested medicinal plant materials. The harvested raw materials
should be transported promptly in clean, dry conditions. They may be placed in
clean baskets, dry sacks, trailers, hoppers, or other well-aerated containers and car-
ried to a central point for transport to the processing facility.
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