Medicinal plants and natural products can play a significant role in mitigation of mercury toxicity

Heavy metal stress and mitogen activated kinase transcription factors in plants: Exploring heavy metal-ROS influences on plant signalling pathways

Due to their stationary nature, plants are exposed to a diverse range of biotic and abiotic stresses, of which heavy metal (HM) stress poses one of the most detrimental abiotic stresses, targeting diverse plant processes. HMs instigate the overproduction of reactive oxygen species (ROS), and to mitigate the adverse effects of ROS, plants induce multiple defence mechanisms. Besides the negative implications of overproduction of ROS, these molecules play a multitude of signalling roles in plants, acting as a central player in the complex signalling network of cells. One of the ROS-associated signalling mechanisms is the mitogen-activated protein kinase (MAPK) cascade, a signalling pathway which transduces extracellular stimuli into intracellular responses. Plant MAPKs have been implicated in signalling involved in stress response, phytohormone regulation, and cell cycle cues. However, the influence of various HMs on MAPK activation has not been well documented. In this review, we address and summarise several aspects related to various HM-induced ROS signalling. Additionally, we touch on how these signals activate the MAPK cascade and the downstream transcription factors that influence plant responses to HMs. Moreover, we propose a workflow that could characterise genes associated with MAPKs and their roles during plant HM stress responses.

Etlingera hemisphaerica Alters One-Dimensional Profile of Serum Proteins Due to Mercury Chloride in Rats (Rattus norvegicus)

<b>Background and Objective:</b> Several previous studies have shown that leaf ethanolic extract of <i>Etlingera hemisphaerica</i> (LE3H) has the potential to reduce the toxicity and teratogenicity effects of mercury. This study aimed to describe the effects of LE3H on the protein profile of <i>Rattus norvegicus</i> serum due to treatment with HgCl₂. <b>Materials and Methods:</b> Four groups of male rats, K1 was injected intraperitoneally (IP) HgCl₂ (5 mg kg¹ b.wt.), K2 was injected IP HgCl₂ (5 mg kg¹ b.wt.) and after 24 hrs it was gavage LE3H (0.27 mg g¹ b.wt.) every day for seven days, K3 was injected IP HgCl₂ (5 mg kg¹ b.wt.), after 24 hrs was gavage LE3H (0.55 mg g¹ b.wt.) every day for seven days. The K0 as control, received double-distilled water. On the ninth day, the experimental animals were killed via CD and blood was drawn from the heart to obtain serum. Serum samples were measured for protein content using the Lowry and serum was separated using the One-Dimensional Sodium dodecyl Sulfate-Polyacrylamide gel Electrophoresis (1D SDS-PAGE) technique. <b>Results:</b> The electropherograms showed four bands, 264.77, 219.53, 98.57 and 37.29 kDa, whose intensity significantly increased due to HgCl₂ treatment and then decreased to close to the control condition with LE3H administration. The results also revealed four bands, 31.95, 28, 06, 26, 29 and 15.09 kDa, whose intensity decreased significantly due to HgCl₂ treatment and then increased to close to the control condition by LE3H administration. <b>Conclusion:</b> The LE3H change profile of the eight blood serum protein bands due to HgCl₂ approximates the control condition in <i>R. norvegicus</i>.

Honey Can Obviate Heavy Metal Toxicity: A Review

Toxicity caused by heavy metals inflicts a grave global menace to the habitat and inhabitants. Arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg) are the non-essential yet harmful heavy metals commonly associated with pollution and resultant health complications. Typical chelating/complexing agents are not worthy of combating heavy metal-induced sub-chronic and chronic toxicities. It transpires from scientific data mining that, honey obviates investigational heavy metal toxicity. This review aims to collate such investigations conducted against As, Cd, and Pb toxicity. There is a total of 19 pre-clinical works demonstrating the ameliorative effect of honey against empirical As, Cd, and Pb toxicity. Pre-clinical reports against Hg and clinical study against these heavy metals could not found. From the outcome of the current literature investigation, it seems that honey has a marked heavy metal toxicity meliorative effect which is chiefly ascribed to its innate antioxidant effect due to its diverse polyphenol content.

A Review on Experimentally Proven Medicinal Plants and Their Constituents against Fluoride Toxicity

Fluoride toxicity, principally by polluted groundwater, is regarded as a momentous global public health risk, as there is no particular and proven treatment for chronic fluoride toxicity i.e., fluorosis which leads to several serious health complications. Scientific literature reveals several medicinal plants and natural products alleviate experimentally induced fluoride toxicity. The present review attempts to collate those experimental studies on medicinal plants and plant derived natural products with fluoride toxicity ameliorative effects. Literature scrutiny was performed by using online bibliographic databases and the studies for the last 15 years were considered. Minerals and semi-synthetic or synthetic analogs of natural products were excluded. Literature study revealed that 25 medicinal plants and 17 natural products exhibited significant protection from fluoride toxicity in experimental animal models i.e., preclinical studies. Two clinical studies on medicinal plants were also found in literature showing beneficial yet poorly correlated outcome. Relevant research in this field could lead to development of a potentially useful agent in therapeutic management of fluoride toxicity in humans.

Integrated review of the nexus between toxic elements in the environment and human health

Emerging pollutants in the environment due to economic development have become a global challenge for environmental and human health management. Potentially toxic elements (PTEs), a major group of pollutants, have been detected in soil, air, water and food crops. Humans are exposed to PTEs through soil ingestion, consumption of water, uptake of food crop products originating from polluted fields, breathing of dust and fumes, and direct contact of the skin with contaminated soil and water. The dose absorbed by humans, the exposure route and the duration (i.e., acute or chronic) determine the toxicity of PTEs. Poisoning by PTEs can lead to excessive damage to health as a consequence of oxidative stress produced by the formation of free radicals and, as a consequence, to various disorders. The toxicity of certain organs includes neurotoxicity, nephrotoxicity, hepatotoxicity, skin toxicity, and cardiovascular toxicity. In the treatment of PTE toxicity, synthetic chelating agents and symptomatic supportive procedures have been conventionally used. In addition, there are new insights concerning natural products which may be a powerful option to treat several adverse consequences. Health policy implications need to include monitoring air, water, soil, food products, and individuals at risk, as well as environmental manipulation of soil, water, and sewage. The overall goal of this review is to present an integrated view of human exposure, risk assessment, clinical effects, as well as therapy, including new treatment options, related to highly toxic PTEs.

Effect of methylmercury on fetal neurobehavioral development: an overview of the possible mechanisms of toxicity and the neuroprotective effect of phytochemicals

Methylmercury (MeHg) is a global environmental pollutant with neurotoxic effects. Exposure to MeHg via consumption of seafood and fish can severely impact fetal neurobehavioral development even when MeHg levels in maternal blood are as low as about 5 μg/L, which the mother tolerates well. Persistent motor dysfunctions and cognitive deficits may result from trans-placental exposure. The present review summarizes current knowledge on the mechanisms of MeHg toxicity during the period of nervous system development. Although cerebellar Purkinje cells are MeHg targets, the actions of MeHg on thiol components in the neuronal cytoskeleton as well as on mitochondrial enzymes and induction of disturbances of glutamate signaling can impair extra-cerebellar functions, also at levels well tolerated by adult individuals. Numerous herbal substances possess neuroprotective effects, predominantly represented by natural polyphenolic molecules that might be utilized to develop natural drugs to alleviate neurotoxicity symptoms caused by MeHg or other Hg compounds.

ICP-MS determination of elemental abundance in traditional medicinal plants commonly used in the Kingdom of Saudi Arabia

Medicinal plants are widely used in the Kingdom of Saudi Arabia to treat various ailments in the form of folk medicine. Forty four such medicinal plant samples were collected from local markets and evaluated for the presence of 14 elements (Mn, Cr, Co, Ni, Cu, Mo, Al, Pb, Ba, Zn, Ag, Hg, Bi, Cd). Microwave-assisted digestion with inductively coupled plasma-mass spectrometry (ICP-MS) was applied to determine the elemental composition in these medicinal plants. Widespread occurrence of these elements was observed in all plant samples, except for Bi and Co where the lowest mean values of 0.03 ± 0.04 and 0.03 ± 0.15 were observed, respectively. The descending order for mean (μg/g) elemental occurrence observed was as follows: Ba > Al > Zn > Ni > Mn > Ba > Hg > Mo > Cu > Cr > Ag > Cd > Co > Bi, whereas the range for these elements in the 44-medicinal plants was as follows: Pb > Al > Zn > Ni > Mn > Cu > Mo > Ag > Ba > Hg > Co > Cd > Cr > Bi. Pb, Hg and Cd were found beyond the maximum limits in these medicinal plants, while the remaining elements were found well within the range of maximum limits. A number of medicinal plants showed high amounts of these elements. Some plants contained more than one element, such as Foeniculum vulgare Mill (Pb, Hg, Cd), Ricinus communis (Pb, Cd), Vigna radiata (Pb, Cd) and Sesamum indicum (Pb, Hg). The data matrix was validated through the statistical tools of principal component analysis (X² = 160.44, P = .00), Pearson's correlation (P = .01 and 0.05), and K-mean cluster analysis (F = 104.55, P = .00). The findings of the study provide baseline data for the comparative analysis of these medicinal plants, which may help select safe medicinal plants in terms of consumer-based use and its utilisation for the treatment of various ailments.

Protective Role of the Essential Trace Elements in the Obviation of Cadmium Toxicity: Glimpses of Mechanisms

Cadmium (Cd) is toxic non-essential heavy metal that precipitates adverse health effects in humans and animals. Chelation therapy, the typical treatment for cadmium toxicity, has certain safety and efficacy issues to treat long term cadmium toxicity, in particular. Recent studies have shown that essential trace elements can play important roles in obviating experimental Cd toxicity. This study organizes and reviews the prototypical evidences of the protective effects of essential trace elements against Cd toxicity in animals and attempts to point out the underlying mechanisms. Zinc, selenium, iron, and combinations thereof are reported to be active. The major mechanisms elucidated inter alia are-induction of metallothionein (MT) synthesis and Cd-MT binding (for zinc), modulation of oxidative stress and apoptosis, interference in cadmium absorption and accumulation from body-thereby maintenance of essential metal homeostasis and cytoprotection. Based on the findings, essential trace elements can be recommended for the susceptible population. The application of these trace elements appears beneficial for both the prevention and remediation of long-term Cd toxicity operative via multiple mechanisms with no or minimal adverse effects as compared to the conventional chelation therapy.

Mitigative effect of green tea extract against mercury(II) chloride toxicity in Allium cepa L. model

Mercury (Hg) is a highly toxic heavy metal for all organisms. In the present study, the mitigative role of 190 mg/L and 380 mg/L doses of green tea extract (GTex) against mercury(II) chloride (HgCI₂)-induced toxicity was evaluated in Allium cepa L. For this aim, selected physiological, genotoxicity, and biochemical parameters as well as meristematic cell injuries in the roots were investigated. Ratios of catechin and caffeine in GTex were determined by HPLC analysis. Also, free radical scavenging activity of GTex was tested against superoxide and hydrogen peroxide radicals. As a result of HgCI₂ application, germination percentage, root elongation, weight gain, and mitotic index (MI) declined, while the frequency of micronucleus (MN), chromosomal abnormalities (CAs), and meristematic cell damages increased. HgCI₂ administration also led to a significant increase in malondialdehyde content, superoxide dismutase, and catalase activities which are signs of oxidative stress. On contrary, applications of GTex together with HgCI₂ reduced HgCI₂-induced adverse effects in all parameters in a dose-dependent manner. Antioxidant components in GTex were listed as caffeine, epigallocatechin gallate, epigallocatechin, epicatechin gallate, and catechin according to their abundance. GTex exhibited a strong scavenging ability in the presence of superoxide and hydrogen peroxide radicals. The present study revealed the strong protective capacity of GTex against HgCI₂-induced toxicity in A. cepa owing to its high antioxidant content with a multifaceted perspective. With this study, a reliable starting point was established for future studies investigating the more common and diverse use of GTex against toxic substances.

Promising effects of gingerol against toxins: A review article

Ginger is a medicinal and valuable culinary plant. Gingerols, as an active constituent in the fresh ginger rhizomes of Zingiber officinale, exhibit several promising pharmacological properties. This comprehensive literature review was performed to assess gingerol's protective and therapeutic efficacy against the various chemical, natural, and radiational stimuli. Another objective of this study was to investigate the mechanism of anti-inflammatory, antioxidant, and antiapoptotic properties of gingerol. It should be noted that the data were gathered from in vivo and in vitro experimental studies. Gingerols can exert their protective activity through different mechanisms and cell signaling pathways. For example, these are mitogen-activated protein kinase (MAPK), nuclear factor-kappa B (NF-kB), Wnt/β-catenin, nuclear factor erythroid 2-related factor 2/antioxidant response element (Nrf2/ARE), transforming growth factor beta1/Smad3 (TGF-β1/Smad3), and extracellular signal-related kinase/cAMP-response element-binding protein (ERK/CREB). We hope that more researchers can benefit from this review to conduct preclinical and clinical studies, treat cancer, inflammation, and attenuate the side effects of drugs and industrial pollutants.

Leaf ethanolic extract of Etlingera hemesphaerica Blume mitigates defects in fetal anatomy and endochondral ossification due to mercuric chloride during the post-implantation period in Mus musculus

This study aimed to investigate the effectiveness of leaf ethanolic extract of Etlingera hemisphaerica (LE3H) in reducing defects in fetal anatomy and endochondral ossification in mice induced by HgCl₂ during the post-implantation period. Pregnant mice were divided into four groups, each consisting of 10 dams, and received drink and food ad libitum. The first group was administered LE3H (E1), the second one HgCl₂ (E2), the third one HgCl₂+LE3H (E3), and the fourth was control (E0), administered double-distilled water only. HgCl₂ (5 mg/kg bw) was administrated by injection intraperitoneally on gestation day (GD)9 and LE3H (0.39 mg/g bw) was administered by gavage on GD10. The treated and control animals were killed by cervical dislocation on GD18, dissected, and the morphologically normal living fetuses (MNLF) were collected. The MNLF of E0, E1, E2, and E3 from 5 dams were fixed with Bouin solution, and observed using the free hand razor blade technique for soft tissue examination. The remaining MNLF were fixed with 96% ethanol, and then stained with Alizarin Red S and Alcian Blue for ossification examination. Index of length of ossified part (ILOP) of humerus, index of width of ossified part (IWOP) of humerus, ILOP of femur, and IWOP of femur were calculated. E2 had higher cases of anatomical defects (74,6%) than E3 (48.9%), E1 (15.0%), and E0 (0%). E2 had humerus IWOP of 0.82±0.03, which was significantly lower than that of E0 (0.89±0.04) and E1 (0.89±0.03), while that of E1 and E0 was not significantly different from each other. Meanwhile, IWOP in E3 (0.88±0.03) was significantly higher than that in E2, but not different from that in E1 and E0. Thus, LE3H mitigated defects in fetal anatomy and endochondral ossification induced by HgCl₂ in mice.

Curcumin: Could This Compound Be Useful in Pregnancy and Pregnancy-Related Complications?

Curcumin, the main polyphenol contained in turmeric root (Curcuma longa), has played a significant role in medicine for centuries. The growing interest in plant-derived substances has led to increased consumption of them also in pregnancy. The pleiotropic and multi-targeting actions of curcumin have made it very attractive as a health-promoting compound. In spite of the beneficial effects observed in various chronic diseases in humans, limited and fragmentary information is currently available about curcumin’s effects on pregnancy and pregnancy-related complications. It is known that immune-metabolic alterations occurring during pregnancy have consequences on both maternal and fetal tissues, leading to short- and long-term complications. The reported anti-inflammatory, antioxidant, antitoxicant, neuroprotective, immunomodulatory, antiapoptotic, antiangiogenic, anti-hypertensive, and antidiabetic properties of curcumin appear to be encouraging, not only for the management of pregnancy-related disorders, including gestational diabetes mellitus (GDM), preeclampsia (PE), depression, preterm birth, and fetal growth disorders but also to contrast damage induced by natural and chemical toxic agents. The current review summarizes the latest data, mostly obtained from animal models and in vitro studies, on the impact of curcumin on the molecular mechanisms involved in pregnancy pathophysiology, with the aim to shed light on the possible beneficial and/or adverse effects of curcumin on pregnancy outcomes.

The Role of Probiotics in the Amelioration of Cadmium Toxicity

Cadmium is extremely toxic heavy metal, and there is no specific, safe, and efficacious therapeutic management of cadmium toxicity. Scientific literature reveals several probiotic microorganisms which alleviate experimentally induced cadmium toxicity in animals. The present review attempts to collate the experimental studies on probiotics and probiotic-derived natural products with cadmium toxicity ameliorative effects. Literature survey revealed that seven (7) types of probiotic microorganisms exhibited significant protection from cadmium toxicity in experimental pre-clinical studies. Clinical study with significant outcome was not found in literature. From the outcomes of the pre-clinical studies, it appears that probiotics have the prospect for alleviation and treatment of cadmium toxicity.

Probiotics against alleviation of lead toxicity: recent advances

Lead is a toxic heavy metal and there is no specific, safe and efficacious therapeutic management of lead toxicity. Scientific literature reported that some probiotic microorganisms alleviated experimentally induced lead toxicity. The present review attempts to collate the experimental studies on probiotics with ameliorative effects. Literature survey revealed that four (4) types of probiotic microorganisms exhibited significant protection from lead toxicity in experimental pre-clinical studies. No clinical study with significant outcome was found in the literature. From the outcomes of the preclinical studies it appears that probiotics are prospective for alleviation and treatment of lead toxicity.