Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5217_Библиотеки_им_академика_М_И_Перельмана.pdf
Phytovolatilization
Phytoaccumulation/
phytoextraction
Phytodegradation
Rhizodegradation
Methods Used in Organic
Pollutants
Phytodegradation
Rhizodegradation
Phytovolatilization
Contaminants uptake
Phytostabilization
Phytoextraction
Methods Used in Metal
Contaminants
Rhizofiltration
Phytostabilization
PHYTOROMEDIATION TYPES
Figure 7.8: Uptake mechanisms by plants with phytoremediation technology [77].
Chapter 7 Impact of heavy metal on the medicinal and aromatic plants’ biochemistry 283
Hyperaccumulation is a process in which certain plants absorb significant amounts of
heavy metals and store them within their tissues [77]. This mechanism is particularly
effective for plant species thriving in metal-contaminated soils. Studies have identified plants such as Brassica juncea, Helianthus annuus, and Thlaspi caerulescens as
highly efficient at extracting heavy metals from the soil and accumulating them
within their tissues [78]. These species play a crucial role in remediating soils polluted
with metals like cadmium, lead, zinc, and copper.
nated soils involves the application of soil amendments. These substances help reduce the mobility and bioavailability of heavy metals in the soil. For example, adding organic materials such as compost and biofertilizers assists in stabilizing heavy
metals and limiting their movement. Likewise, using mineral amendments like lime
and gypsum can alter soil pH levels, thereby decreasing heavy metal availability to
plants [79].
Beyond phytoremediation, another effective method for detoxifying contami-
Figure 7.9: Flower spike of Lavandula angustifolia.
284 Negar Valizadeh and Gülen Özyazıcı
7.11 Selection of heavy metal-resistant plants
An effective approach to mitigating the adverse effects of heavy metals is the selection
of plant species that exhibit natural resistance to these contaminants. Such plants
have evolved specialized mechanisms to cope with heavy metal stress, either by absorbing and isolating these metals within their tissues or by preventing their uptake
at the cellular level. Among medicinal and aromatic plants, species such as Lavandula
angustifolia (lavender), Mentha piperita (peppermint), and Ocimum basilicum (basil)
have shown significant resilience to heavy metal exposure. These plants are capable
of growing and adapting even in environments with contaminated soils (Figure 7.9).
Plants employ various mechanisms to resist heavy metal stress, including the production of antioxidant compounds, alterations in metal transport pathways, and the synthesis of chemical substances that confine heavy metals within specific tissues. For example, certain medicinal plants can limit heavy metal absorption or stabilize these
contaminants in the soil by secreting compounds such as organic acids and phosphates
[80, 81].
A study by Pandey et al. [81] investigated the adaptation mechanisms of clary sage
(Salvia sclarea L.) when exposed to high zinc concentrations (900 micromoles of Zn) over
an eight-day period in a hydroponic system. The research aimed to understand the plant’s
zinc tolerance strategies by assessing factors such as nutrient absorption, leaf pigmentation, phenolic compound content, photosynthetic efficiency, and structural changes in the
leaves. To analyze zinc distribution and essential element levels – including calcium, magnesium, iron, manganese, and copper – the study utilized inductively coupled plasma
mass spectrometry (ICP-MS). Findings revealed that S. sclarea, as a zinc-accumulating species, counteracts toxic zinc levels by increasing the concentrations of iron, calcium, and
manganese ions in its leaves. This adjustment helps sustain photosynthetic efficiency and
supports the functionality of photosystems I (PSI) and II (PSII).
Chapter 7 Impact of heavy metal on the medicinal and aromatic plants’ biochemistry 285
Furthermore, increased zinc levels notably boosted the synthesis of phenolic compounds and anthocyanins in the leaves, which play a vital role in detoxifying zinc and
reducing oxidative stress. Although the plants were exposed to high zinc concentrations, indicators of damage, including lipid peroxidation and electrolyte leakage, exhibited only slight elevations. These results suggest that S. sclarea could be a practical
and cost-efficient option for phytoextraction or phytostabilization of zinc-polluted
soils. Moreover, genetic engineering holds great promise for enhancing plant tolerance to heavy metals. The incorporation of specific genes that aid in detoxifying
heavy metals can strengthen a plant’s capacity to absorb and neutralize these contaminants. For instance, introducing MT and HMA genes into medicinal plants has been
found to improve their resistance to heavy metals such as cadmium and lead [74, 82].
7.12 Case studies
Extensive research has explored the impact of heavy metals like cadmium, lead, and copper, which are major contaminants in agricultural soils. For example, Es-Sabihi et al. [83]
studied the role of SA in alleviating copper toxicity in Salvia officinalis L. Their findings
indicated that copper stress significantly hindered both stem and root growth while also
depleting calcium, phosphorus, and potassium levels in leaves and roots. Interestingly,
exposure to copper stress increased essential oil yield by 16.66% compared to control
plants. However, the application of SA enhanced plant growth and replenished calcium,
phosphorus, and potassium content in leaves and roots. Notably, treatment with 0.5 mM
SA led to a 116.66% increase in essential oil content relative to untreated plants under
copper stress. In terms of essential oil composition, copper stress resulted in a 19% decline in oxygenated monoterpenes, particularly α-thujone, camphor, and 1,8-cineole.
However, SA application effectively restored these compounds to levels observed in nonstressed plants. These findings indicate that SA, especially at 0.5 mM concentration, can
effectively mitigate copper-induced stress while enhancing growth, yield, and essential
oil quality in S. officinalis L.
A study by Pirooz et al. [84] examined the effects of nitric oxide and silicon, both
separately and together, on rosmarinic acid and essential oil production in S. officinalis
leaves under normal and copper-stressed conditions. The findings revealed that high
copper levels led to a decline in biomass and polyphenol content. However, moderate
copper concentrations, particularly at 200 µM, were associated with an increase in polyphenol levels, essential oil production, and antioxidant activity in the leaves.Similarly,
research by Elzaawely et al. [85] found that treating shell ginger (Alpinia zerumbet
(Pers.) B.L. Burtt & R.M. Sm.) with 500 mM copper sulfate resulted in a reduction in total
essential oil yield. Interestingly, despite the overall decrease, certain essential oil components, including 1,8-cineole, linalool, camphor, borneol, and cumin aldehyde, showed increased concentrations.
286 Negar Valizadeh and Gülen Özyazıcı
Lajayer et al. [86] investigated the impact of different copper and zinc concentrations on the growth, nutrient composition, and essential oil production of Mentha pu-
legium L. Their study revealed that the best growth outcomes, including plant height,
shoot dry weight, essential oil content, and yield, were observed when 5 mg/kg copper
and 10 mg/kg zinc were applied. The combined use of these metals at these concentrations enhanced the uptake of essential nutrients such as potassium, manganese, iron,
copper, and zinc in the aerial parts of the plants. Moreover, notable increases were
recorded in essential oil constituents, including pulegone, cis-isopulegone, α-pinene,
sabinene, 1,8-cineole, and thymol. These findings suggest that appropriate levels of
copper and zinc not only promote plant growth and nutrient absorption but also
boost essential oil yield and quality in M. pulegium L.
Babashpour-Asl et al. [87] examined the impact of selenium nanoparticles on Cor-
iandrum sativum L. under cadmium-induced stress. Cadmium was introduced at concentrations of 0, 4, and 8 mg/L, while selenium nanoparticles were applied as a foliar spray
at 0, 20, 40, and 60 mg/L. The findings revealed that cadmium stress led to increased
cadmium accumulation in both roots and shoots of coriander; however, the application
of selenium nanoparticles significantly reduced this uptake. Exposure to the highest cadmium concentration resulted in decreased root and shoot biomass, chlorophyll content,
and relative water content (RWC), whereas selenium nanoparticles improved these parameters. Additionally, cadmium stress elevated proline and malondialdehyde (MDA)
levels, while selenium nanoparticle treatment lowered MDA levels, thereby reducing
lipid peroxidation. Changes in essential oil composition were also observed, particularly
in compounds such as n-decanal, 2E-dodecanal, 2E-decanal, and n-nonane, in response
to cadmium stress and selenium supplementation. The study concluded that selenium
nanoparticles alleviated cadmium-induced stress by enhancing growth, biochemical
properties, and essential oil quality in coriander plants.
Farajzadeh Memari-Tabrizi et al. [88] investigated the effects of silicon nanoparticles on Satureja hortensis L. cultivated in cadmium-contaminated soil. Cadmium
stress significantly reduced root and shoot biomass, along with RWC, while increasing
cadmium accumulation in plant tissues and proline levels. Interestingly, moderate
cadmium stress led to an increase in total phenolic content (TPC), total flavonoid content (TFC), and essential oil production. Foliar application of silicon nanoparticles (1.5
and 2.25 mM) under cadmium stress improved plant growth and boosted essential oil
yield. Key essential oil components, including carvacrol, γ-terpinene, p-cymene, and
thymol, were influenced by both cadmium stress and silicon nanoparticle treatments.
Overall, the study suggested that applying silicon nanoparticles at concentrations of
1.5–2.25 mM mitigated cadmium-induced stress by enhancing physiological and biochemical characteristics in S. hortensis L.
A study examined the effects of cadmium and lead on seed germination, growth
characteristics, and essential oil composition in Ocimum basilicum L [89]. Soil was
treated with cadmium (0, 5, 10, and 20 mg/kg) and lead (0, 100, 200, and 400 mg/kg) over
a 2-month period. The findings indicated that exposure to these heavy metals adversely
Chapter 7 Impact of heavy metal on the medicinal and aromatic plants’ biochemistry 287
impacted seed germination, flowering, stem growth, leaf area, and dry biomass. Gas
chromatography-mass spectrometry (GC-MS) analysis identified 38 compounds in the
essential oil, with major constituents including estragole, 2,6-octadienal, caryophyllene
oxide, caryophyllene, phthalic acid, and geranial. Although cadmium and lead stress
negatively affected plant growth and morphology, they also enhanced essential oil yield
and modified its composition. These results suggest that O. basilicum may hold promise
for phytoremediation in contaminated soils.
Poursaeid et al. [90] also reported that cadmium exposure stimulated essential oil
production in basil. Their study found that different cadmium concentrations increased the synthesis of key compounds such as geranial, linalool, and estragole in a
dose-dependent manner. These findings indicate that cadmium stress, at specific levels, can influence the biosynthesis of active metabolites in basil plants.
Similarly, Mohammed et al. [91] investigated the effects of cadmium-contaminated
irrigation on two mint species: spearmint (Mentha × piperita L.) and mint (M. spicata
var. crispa L.). Their research revealed significant phytotoxic effects, including abnormal growth patterns and a decline in total chlorophyll levels due to cadmium exposure.
Youssef [92] also observed that applying cadmium (5, 10, 15, 20, and 25 ppm) and
lead (100, 350, 750, 1,000, and 1,500 ppm) to Ocimum basilicum L. (basil) increased essential oil yield. However, a separate study on Melissa officinalis L. (lemon balm)
found that soil contamination with cadmium at concentrations of 10, 20, and 30 mg/kg
over 3 months led to a significant decrease in essential oil production [93]. This decline was likely attributed to structural and functional damage that interfered with
essential oil biosynthesis.
Another study assessed the essential oil yield of vetiver grass cultivated in Botswana’s mine tailings and explored the effects of chelating agents such as ethylenediaminetetraacetic acid (EDTA) and arbuscular mycorrhizal fungi (AMF) on oil production. The findings revealed that vetiver grass grown in mine tailings produced a
higher quantity of essential oil compared to those in uncontaminated soils. In sterilized soil, the oil yield was only 0.26%, whereas it increased to 0.86% in mine tailings.
Further enhancements were observed with the addition of EDTA or AMF, raising the
yield to 0.95% and 0.89%, respectively. These improvements were attributed to greater
heavy metal uptake, which induced stress in the plants and stimulated the production
of secondary metabolites, including essential oils. Notably, despite the elevated heavy
metal concentrations in mine tailings, the extracted essential oils contained negligible
amounts of these metals, highlighting the suitability of vetiver grass for thriving in
polluted environments while producing high-quality essential oils [94].
Amirmoradi et al. [95] examined how different concentrations of cadmium (10,
20, 40, 60, 80, and 100 ppm) and lead (100, 300, 600, 900, 1,200, and 1,500 ppm) in irrigation water affected peppermint (M. piperita). Their study demonstrated that as cadmium and lead levels increased, essential oil content decreased significantly, accompanied by visible symptoms of phytotoxicity. Likewise, Azimychetabi et al. [96]
investigated the impact of cadmium on peppermint and found that it altered the com-
288 Negar Valizadeh and Gülen Özyazıcı
position of essential oils. Specifically, pulegone and menthofuran concentrations rose,
whereas menthol levels declined.
Kunwar et al. [65] investigated the effects of lead (500, 600, 750, and 900 ppm), copper (270, 300, 500, and 700 ppm), and cadmium (6, 10, 20, and 30 ppm) on M. spicata and
O. basilicum. Their findings indicated that in O. basilicum, total essential oil yield, particularly its main component linalool, increased, whereas methyl chavicol levels declined.
In contrast, M. spicata exhibited no significant alterations in either essential oil content
or composition.
Additionally, Sulastri and Tampubolon [97] examined cadmium’s influence on
various plant species, including Vetiveria zizanioides, Cymbopogon citratus, C. nardus,
Curcuma xanthorrhiza, Pogostemon cablin, and Alpinia galanga. The study highlighted
species-specific variations, with essential oil production in V. zizanioides doubling,
while other species showed minimal or no significant changes.
Sa et al. [98] investigated how different lead concentrations in soil influenced the
growth of Mentha crispa. Their findings showed that increased lead contamination
significantly enhanced essential oil production and modified its chemical profile. Notably, the proportion of carvone, the dominant component of mint essential oil, increased to 90% in lead-contaminated soils. Prasad et al. [99] carried out a pot culture
experiment to assess how increasing chromium and lead levels (30.0 and 60.0 mg/kg
of soil) influenced yield, essential oil composition, and heavy metal accumulation in
three mint species: M. piperita, M. arvensis, and M. citrata. The study found that while
M. arvensis exhibited no significant changes in fresh weight yield under chromium
and lead exposure, its essential oil yield declined considerably compared to the control. Conversely, M. piperita demonstrated increased fresh weight yield, root biomass,
and essential oil production under higher heavy metal concentrations, whereas
M. citrata experienced reductions in these parameters.
The application of chromium and lead also led to significant alterations in essential oil composition. In M. arvensis and M. piperita, levels of α-pinene, β-pinene, sabinene, β-myrcene, limonene, menthone, and isomenthone changed notably, while in
M. citrata, sabinene, pinene, and linalyl acetate concentrations were affected. Additionally, heavy metal accumulation in both the aerial parts and roots increased across
all three mint species, with the highest levels observed in the roots. Based on these
results, M. piperita was identified as the most suitable species for cultivation in chromium- and lead-contaminated soils, followed by M. arvensis and M. citrata.
Zheljazkov et al. [100] examined how cadmium, lead, copper, and their combinations affected Anethum graveolens L. (dill), Mentha × piperita L. (mint), and Ocimum
basilicum L. (basil). Their findings indicated that exposure to these heavy metals led
to a reduction in menthol content within mint essential oil and a decline in total oil
yield in basil. Likewise, at the highest tested copper concentration (150 mg/L), a significant decrease in dill oil content was observed.
In a separate study, Nabi et al. [101] explored the impact of nickel on menthol
mint (Mentha arvensis L.) by growing seedlings in soils treated with nickel at concen-
Chapter 7 Impact of heavy metal on the medicinal and aromatic plants’ biochemistry 289
trations of 20, 40, 60, 80, and 100 mg/kg. The results revealed a biphasic response,
where lower nickel levels (20 mg/kg) stimulated essential oil production, while higher
concentrations led to a decline. Interestingly, at 20 mg/kg, menthol content decreased,
whereas menthone and menthyl acetate levels increased.
Biswas et al. [102] investigated the effects of arsenic exposure using disodium hydrogen arsenate [Na₂HAsO₄•7 H₂O] at soil concentrations of 10, 50, and 150 ppm. Their
study on basil (Ocimum basilicum) demonstrated a dose-dependent effect on essential
oil production. While lower arsenic concentrations (10 and 50 ppm) increased oil
yield, a higher level (150 ppm) resulted in a decline. Additionally, arsenic exposure
influenced oil composition, with linalool levels rising and 1,8-cineole and methyl eugenol concentrations decreasing.
Several studies have investigated the impact of soils contaminated with complex
heavy metal mixtures on essential oil content. For example, Scora and Chang [103]
found that the composition of peppermint (Mentha piperita) essential oil remained
unchanged when the plant was cultivated in soils containing cadmium, chromium,
copper, nickel, lead, and zinc. Similarly, Pandey et al. [104] studied Cymbopogon mar-
tinii (palmarosa) grown in soil contaminated with tannery effluent, which contained
substantial amounts of chromium, nickel, lead, and cadmium. Their results indicated
that despite the presence of these heavy metals, palmarosa’s essential oil yield remained unaffected.
In another study, Gautam and Agrawal [105] examined Cymbopogon citratus (lemongrass) cultivated in soil mixed with sludge containing heavy metals and supplemented
with wastewater effluent at different concentrations (5%, 10%, and 15% by weight). The
findings suggested that lower concentrations (5% and 10%) enhanced total essential oil
production, while the effects of higher concentrations were not specified.
Additionally, Gharib et al. [106] conducted a comparative analysis of wild mint
(Mentha longifolia) collected from both polluted and non-polluted areas along the Nile
River in Egypt. Their study revealed that plants from polluted regions produced
higher essential oil yields. Furthermore, antioxidant activity, assessed using the DPPH
(2,2-diphenyl-1-picrylhydrazyl) free radical scavenging assay, was significantly greater
in oils from polluted sites. However, the oil composition varied, with menthone levels
increasing and pulegone concentrations decreasing in plants exposed to pollution.
Givianrad and Hashemi [107] analyzed the chemical makeup of Tanacetum poly-
cephalum Sch.Bip., a species belonging to the Asteraceae family. The plant samples
were collected from different distances around the Veshnavah mine in Qom, Iran.
Their study found that the concentration of chemical compounds increased as the distance from the mine increased. The primary heavy metals detected in the soil samples
from these regions were copper and silver. The research suggests that heavy metals
significantly impact essential oil production and composition, depending on factors
such as the type and concentration of the metal, the plant species, and surrounding
environmental conditions. At lower concentrations, certain metals, including copper,
cadmium, and lead have been shown to enhance both the total yield of essential oils
290 Negar Valizadeh and Gülen Özyazıcı
and the presence of specific components within them. For instance, increased essential oil production has been noted in plants such as sage, coriander, and wild mint
when exposed to minimal levels of heavy metals.
On the other hand, when present in higher concentrations, these metals exhibit phytotoxic effects, leading to inhibited growth, disruptions in essential oil biosynthesis, and
undesirable changes in the oils’ chemical composition. Additional negative effects include
reduced chlorophyll content and indications of cellular toxicity. For example, in plants
like shell ginger (Alpinia zerumbet) and basil (Ocimum basilicum), excessive heavy metal
exposure resulted in lower essential oil yields, although certain compounds showed an
increase under these conditions. Studies also indicate that plant responses to heavy metals vary considerably between species. Some, such as Mentha piperita and Vetiveria ziza-
nioides, display greater tolerance or even utilize heavy metals to enhance essential oil
production. In contrast, species like Melissa officinalis experience a significant decline in
essential oil yield when exposed to the same conditions. In summary, while low levels of
heavy metals can enhance essential oil production, excessive amounts generally lead to
reduced yields and alterations in chemical composition. These findings emphasize the importance of evaluating environmental conditions, metal concentrations, and plant species
when dealing with contaminated soils. Furthermore, although low levels of heavy metals
may offer benefits, their potential risks to both the environment and human health must
be carefully considered.
7.13 Conclusions
Plants exhibit various responses to heavy metal-induced stress, ranging from inhibited growth to biochemical adjustments, such as changes in antioxidant enzyme activity. Secondary metabolites, including essential oils, play a vital role in shielding plants
from harmful substances and are notably influenced by these stressors. Research suggests that exposure to heavy metals, known for their toxicity, can impact both the
quantity and composition of essential oils. However, the results remain inconsistent,
with no definitive patterns identified. The fluctuations in essential oil yield and composition in medicinal plants under heavy metal stress are influenced by multiple factors, such as the plant species, the type of essential oil, and the concentration of heavy
metals. Studies indicate that while low levels of heavy metals may promote essential
oil production, higher concentrations generally have an inhibitory effect.
This decline is linked to disruptions in the metabolic pathways responsible for
essential oil synthesis, which may arise from factors such as altered enzymatic activity, increased free radical production, or direct effects on genes regulating these processes. Due to the limited scope of research and the small number of species studied,
two important aspects require further investigation. Firstly, heavy metals impact
gene expression, particularly those involved in essential oil biosynthesis, leading to
Chapter 7 Impact of heavy metal on the medicinal and aromatic plants’ biochemistry 291
either upregulation or downregulation and modifications in associated biochemical
pathways. Secondly, recent studies have explored the feasibility of growing medicinal
plants in heavy metal-contaminated soils as an alternative to food crops. Research on
heavy metal bioaccumulation indicates that many medicinal plants can absorb substantial amounts of these metals; however, this contamination typically does not extend to their essential oils. Despite this, cultivating or harvesting plants in polluted
environments poses challenges, as it may lead to unpredictable variations in essential
oil yield and composition, potentially affecting their quality and therapeutic properties. The limited research available and the narrow focus on specific plant species hinder the broader applicability of findings, highlighting significant knowledge gaps.
To overcome these limitations, future studies should explore the effects of heavy
metals on a wider variety of medicinal plant species and further examine the underlying mechanisms driving these impacts. A deeper understanding of this subject could
aid in developing strategies to sustainably cultivate medicinal plants in contaminated
environments while ensuring the preservation of their beneficial properties.
References
[1] Vaou, N., Stavropoulou, E., Voidarou, C., Tsigalou, C. and Bezirtzoglou, E. (2021). Towards advances
in medicinal plant antimicrobial activity: A review study on challenges and future perspectives.
Microorganisms, 9(10), 2041.
[2] Aware, C. B., Patil, D. N., Suryawanshi, S. S., Mali, P. R., Rane, M. R., Gurav, R. G. and Jadhav,
J. P. (2022). Natural bioactive products as promising therapeutics: A review of natural productbased drug development. South African Journal of Botany, 151(Part B), 512–528.
[3] Boukhatem, M. N. and Setzer, W. N. (2020). Aromatic herbs, medicinal plant-derived essential oils,
and phytochemical extracts as potential therapies for coronaviruses: Future perspectives. Plants,
9(6), 800.
[4] Hubai, K. and Kováts, N. (2024). Interaction between heavy metals posed chemical stress and
essential oil production of medicinal plants. Plants, 13(20), 2938.
[5] Rubio, C., Lucas, J. R. D., Gutiérrez, A. J., Glez-Weller, D., Pérez Marrero, B., Caballero, J. M., Revert,
C. and Hardisson, A. (2012). Evaluation of metal concentrations in Mentha herbal teas (Mentha
piperita, Mentha pulegium, and Mentha species) by inductively coupled plasma spectrometry. Journal
of Pharmaceutical and Biomedical Analysis, 71, 11–17.
[6] Ali, B. and Gill, R. A. (2022). Editorial: Heavy metal toxicity in plants: Recent insights on physiological
and molecular aspects, volume II. Frontiers in Plant Science, 13, 1016257.
[7] Zhao, K., Fu, W., Ye, Z. and Zhang, C. (2015). Contamination and spatial variation of heavy metals in
the soil-rice system in Nanxun County, Southeastern China. International Journal of Environmental
Research and Public Health, 12(2), 1577–1594.
[8] Sharma, P. and Dubey, R. S. (2005). Lead toxicity in plants. Brazilian Journal of Plant Physiology,
17(1), 1–19.
[9] Nagajyoti, P. C., Lee, K. D. and Sreekanth, T. V. M. (2010). Heavy metals, occurrence and toxicity for
plants: A review. Environmental Chemistry Letters, 8(3), 199–216.
[10] Kaur, R., Sharma, R., Thakur, S., Chandel, S. and Chauhan, S. K. (2024). Exploring the combined
effect of heavy metals on accumulation efficiency of Salix alba raised on lead and cadmium
contaminated soils. International Journal of Phytoremediation, 26(9), 1486–1499.
292 Negar Valizadeh and Gülen Özyazıcı
[11] Chen, Y.-G., He, X.-L.-S., Huang, J.-H., Luo, R., Ge, H.-Z., Wołowicz, A., Wawrzkiewicz, M.,
Gładysz-Płaska, A., Li, B., Yu, Q.-X., Kołodyńska, D., Lv, G.-Y. and Chen, S.-H. (2021). Impacts of heavy
metals and medicinal crops on ecological systems, environmental pollution, cultivation, and
production processes in China. Ecotoxicology and Environmental Safety, 219, 112336.
[12] Dinu, C., Gheorghe, S., Tenea, A. G., Stoica, C., Vasile, G. G., Popescu, R. L., Serban, E. A. and Pascu,
L. F. (2021). Toxic metals (As, Cadmium, Ni, Pb) impact in the most common medicinal plant (Mentha
piperita). International Journal of Environmental Research and Public Health, 18(8), 3904.
[13] Asiminicesei, D.-M., Fertu, D. I. and Gavrilescu, M. (2024). Impact of heavy metal pollution in the
environment on the metabolic profile of medicinal plants and their therapeutic potential. Plants,
13(6), 913.
[14] Luo, L., Wang, B., Jiang, J., Fitzgerald, M., Huang, Q., Yu, Z. et al. (2021). Heavy metal contaminations
in herbal medicines: Determination, comprehensive risk assessments, and solutions. Frontiers in
Pharmacology, 11, 595335.
[15] Abou-Arab, A. A. K. and Abou Donia, M. A. (2000). Heavy metals in Egyptian spices and medicinal
plants and the effect of processing on their levels. Journal of Agricultural and Food Chemistry,
48(6), 2300–2304.
[16] Tchounwou, P. B., Yedjou, C. G., Patlolla, A. K. and Sutton, D. J. (2012). Heavy metal toxicity and the
environment. Experientia Supplementum, 101, 133–164.
[17] Singh, N. K., Raghubanshi, A. S. and Upadhyay, A. K. (2016). Arsenic and other heavy metal
accumulation in plants and algae growing naturally in contaminated area of West Bengal, India.
Ecotoxicology and Environmental Safety, 130, 224–233.
[18] Zhao, H., Guan, J., Liang, Q., Zhang, X., Hu, H. and Zhang, J. (2021). Effects of cadmium stress on
growth and physiological characteristics of sassafras seedlings. Scientific Reports, 11, 9913.
[19] Xu, J., Zhang, J., Lv, Y., Xu, K., Lu, S., Liu, X. and Yang, Y. (2020). Effect of soil mercury pollution on
ginger (Zingiber officinale Roscoe): Growth, product quality, health risks and silicon mitigation.
Ecotoxicology and Environmental Safety, 195, 110472.
[20] Usman, K., Abu-Dieyeh, M. H., Zouari, N. and Al-Ghouti, M. A. (2020). Lead (Pb) bioaccumulation and
antioxidative responses in Tetraena qataranse. Scientific Reports, 10, 17070.
[21] Ibrahim, M. H., Chee Kong, Y. and Mohd Zain, N. A. (2017). Effect of cadmium and copper exposure
on growth, secondary metabolites and antioxidant activity in the medicinal plant sambung nyawa
(Gynura procumbens (Lour.) Merr). Molecules, 22(10), 1623.
[22] Fu, H., Yuan, J., Liu, R. and Wang, X. (2023). Effects of cadmium on the synthesis of active
ingredients in Salvia miltiorrhiza. Open Life Sciences, 18(1), 20220603.
[23] Chizzola, R. and Lukas, B. (2005). Variability of the cadmium content in Hypericum species collected
in eastern Austria. Water, Air, & Soil Pollution, 170(1–4), 331–343.
[24] Pinto, A. P., Mota, A. M., De Varennes, A. and Pinto, F. C. (2004). Influence of organic matter on the
uptake of cadmium, zinc, copper and iron by sorghum plants. The Science of the Total Environment,
326(1–3), 239–247.
[25] Salamon, I., Labun, P., Skoula, M. and Fabian, M. (2007). Cadmium, lead and nickel accumulation in
chamomile plants grown on heavy metal-enriched soil. Acta Horticulturae, 749, 231–237.
[26] Schneider, M. and Marquard, R. (1996). Aufnahme und Akkumulation von Cadmium und weiterer
Schwermetalle bei Hypericum perforatum L. und Linum usitatissimum L. Zeitschrift Für Arznei- &
Gewürzpflanzen, 1(2), 111–116.
[27] Doroszewska, T. and Berbeć, A. (2004). Variation for cadmium uptake among Nicotiana species.
Genetic Resources and Crop Evolution, 51(4), 323–333.
[28] Lugon-Moulin, N., Martin, F., Krauss, M. R., Ramey, P. B. and Rossi, L. (2006). Cadmium
concentration in tobacco (Nicotiana tabacum L.) from different countries and its relationship with
other elements. Chemosphere, 63(7), 1074–1086.