Determination of in vitro bioaccessibility of Pb, As, Cd and Hg in selected traditional Indian medicines

Bioaccessibility, exposure and risk assessment of potentially toxic elements and essential micronutrients in ayurvedic, traditional Chinese and Ghanaian medicines

Potentially toxic constituents in traditional medicines remain a concern due to health risks posed to consumers. Thirty-six traditional medicines (TM) consisting of 14 Indian Ayurvedic Medicines, 11 Chinese Traditional Medicines and eleven Ghanaian Traditional Medicines were evaluated using Total Reflection X-ray Fluorescence Spectrometer (T-XRF) after microwave assisted acid digestion. Physiologically Based Extraction Test (PBET) was used to obtain bioaccessible elemental concentrations. Merck XVI multi-element standard were used to evaluate the accuracy of the analytical method. The concentrations of the elements were quantified in (mg kg-1): Cr (0.01-698), Mn (0.01-1140), Fe (15-73300), Ni (1-1340), Cu (3-8160), Zn (0.01-224). The greatest bioaccessible concentrations of arsenic was 0.80 mg kg-1 and 0.44 mg kg-1 in the gastric and intestinal phases respectively. In order to evaluate the human health risks from ingesting these TM, the Acceptable Daily Intake (ADI) was calculated for each medicine based on element-specific bioaccessibility-adjusted concentrations and results compared with the United States Environmental Protection Agency (USEPA) Reference Dose (RfD) limits. The Acceptable Daily Intake (ADI) values for risks were within the USEPA RfD. Hazard quotients (HQ) of TM were < 1, meaning elemental concentrations do not pose non-carcinogenic risks to adult consumers. In summary the methods applied in the study gives a new insight on human health risks of potentially toxic and essential micronutrients elements in TM.

Elemental and Chemical Phase Analyses of Ras-Family Ayurvedic Medicinal Products

Fifteen Ayurvedic medicines of Ras-family (herbo-mineral-metallic preparations) from three reputed manufactures were analysed for elemental quantification and their chemical phase identification using the energy-dispersive (ED) and wavelength-dispersive (WD) X-ray fluorescence (XRF) techniques, and powder X-ray diffraction (XRD) technique, respectively. The low-Z elements C, H, N, S and O constituting a major portion of these medicines were also determined by CHNSO analyser and further used as input for XRF analyses. The elements of concern, Hg, Pb and As, are identified in different medicine products with disquiet concentration values (maximum concentration values range ~ 4-10%) and that too with substantial variations in the products from different manufacturers. These elements are identified mainly in the cinnabar (α-HgS)/metacinnabar (β-HgS), litharge (PbO) and alacranite (As₄S₄) phases in different medicines. Keeping in view the high concentration of chemicals of the Hg, Pb and As elements in the Ras-family medicines, it is vitally required to investigate their bioaccessibility and surmise the associated toxicological aspects. It is suggested that the formation of the bioaccessible toxic chemical forms of the Hg, Pb and As elements be avoided during preparation of the mineral ingredients or these soluble chemical forms be removed at suitable stage of the preparation. In view of large variations observed for the Hg, Pb and As based ingredients in the Ras family Ayurvedic medicine products from different manufacturers, adequate quality control mechanisms and production regulations are recommended.

Compatibility of Niuhuang Jiedu Tablets Results in Attenuated Arsenic Bioaccumulation and Consequent Protection against Realgar-Induced Toxicity in Mice

Niuhuang Jiedu Tablets (NJT) is a popular over-the-counter traditional Chinese medicine (TCM) preparation. It is composed of realgar (As₂S₂) and seven other TCMs. The safety of NJT is of growing concern because arsenic (As) is carcinogenic to humans. The toxicity of realgar in vivo can mainly be attributed to the absorbed and accumulated As. This study investigated the correlation between the detoxification effects of the other TCMs in NJT on realgar and their influences on arsenic accumulation of realgar in mice. Histopathological examination, clinical biochemical test, and metabolic profiling analysis were used to evaluate the toxicity of realgar. The concentration of arsenic in mice whole blood as the hazard indicator was determined by inductively coupled plasma mass spectrometry (ICP-MS). The compatibility of NJT could decrease arsenic bioaccumulation of realgar in mice whole blood and consequently reduce the toxicity of realgar, which could be considered as one detoxification mechanism to realgar in NJT. The combination of Rhei Radix et Rhizoma, Scutellariae Radix, Platycodonis Radix, and Glycyrrhizae Radix et Rhizoma exhibited almost the same effects as NJT in regulating the serum biochemical parameters and metabolic profiles disturbed by realgar and in reducing arsenic accumulation of realgar in mice whole blood.

Mobility and accessibility of Zn, Pb, and As in abandoned mine tailings of northwestern Mexico

Generation, storage, and management of waste coming from industrial processes are a growing worldwide problem. One of the main contributors is the mining industry, in particular tailings generated by historical mining, which are barely maintained, especially in developing countries. Assessing the impact of a mining site to surrounding soils and ecosystems can be complex, especially when determining mobility and accessibility of the contaminants is required to perform ecological and human health risk assessment. As an effort to obtain information regarding mobility and accessibility of some potentially toxic elements (Zn, Pb, and As) from an historical mining site of northwestern Mexico, the abandoned mine tailings of San Felipe de Jesús in central Sonora and adjacent agricultural soils were investigated. Mobility and accessibility were assessed by means of sequential extraction procedures and using simulated physiological media. Additionally, an assessment of accidental oral intake was calculated considering the bioaccessible fractions. Results show that higher concentrations of contaminants were found in sulfide-rich tailings (Zn = 92,540; Pb = 21,288; As = 19,740 mg kg^-1) compared with oxide-rich tailings (Zn = 43,240; Pb = 14,763; As = 13,401 mg kg^-1). Concentrations in agricultural soils were on average Zn = 4755, Pb = 2840, and As = 103 mg kg^-1. Zinc was mainly recovered from labile fractions in oxide-rich tailings (~ 60%) and in a lower amount from sulfide-rich tailings (~ 30%). Pb and As were mainly associated with residual fractions (80-95%) in both types of tailings. The percentage of mobile fractions (sum of water-soluble, exchangeable, and bound to carbonate fractions) in agricultural soils was as follows: Zn ~ 60%, Pb ~ 15%, and As ~ 70%. Regarding the phytoaccessible fraction, the studied elements in mine tailings and agricultural soil samples exceeded the threshold limits, except for As in agricultural soils. According to data obtained, toxic effects were also calculated. As for daily oral intake for non-carcinogenic effects in adults and children, only Pb and As exceeded reference dose values, especially in children exposed to sulfide-rich tailings and agricultural soils. Regarding carcinogenic effects of Pb and As, most of the samples were above acceptable risk values.

Chemical Compositions of Metals in Bhasmas and Tibetan Zuotai Are a Major Determinant of Their Therapeutic Effects and Toxicity

Minerals are alchemically processed as Bhasmas in Ayurvedic medicines or as Zuotai in Tibetan medicines. Ayurveda is a knowledge system of longevity and considers the mineral elixir made from “nature” capable of giving humans perpetual life. Herbo-metallic preparations have a long history in the treatment of various diseases in India, China, and around the world. Their disposition, pharmacology, efficacy, and safety require scientific evaluation. This review discusses the Bhasmas in Ayurvedic medicines and Zuotai in Tibetan medicines for their occurrence, bioaccessibility, therapeutic use, pharmacology, toxicity, and research perspectives. A literature search on Mineral, Bhasma, Ayurvedic medicine, Zuotai, Tibetan medicine, and Metals/metalloids from PubMed, Google and other sources was carried out, and the relevant papers on their traditional use, pharmacology, and toxicity were selected and analyzed. Minerals are processed to form Bhasma or Zuotai to alter their physiochemical properties distinguishing them from environmental metals. The metals found in Ayurveda are mainly from the intentional addition in the form of Bhasma or Zuotai. Bhasma and Zuotai are often used in combination with other herbals and/or animal-based products as mixtures. The advanced technologies are now utilized to characterize herbo-metallic preparations as Quality Assurance/Quality Control. The bioaccessibility, absorption, distribution, metabolism, and elimination of herbo-metallic preparations are different from environmental metals. The pharmacological basis of Bhasma in Ayurveda and Zuotai in Tibetan medicines and their interactions with drugs require scientific research. Although the toxic potentials of Bhasma and Zuotai differ from environmental metals, the metal poisoning case reports, especially lead (Pb), mercury (Hg), and arsenic (As) from inappropriate use of traditional medicines, are increasing, and pharmacovigilance is desired. In risk assessment, chemical forms of metals in Bhasma and Zuotai should be considered for their disposition, efficacy, and toxicity.

Speciation and bioaccessibility of arsenic in traditional Chinese medicines and assessment of its potential health risk

Arsenic in traditional Chinese medicines (TCMs) has caused public concerns about its health risk in recent years due to the high toxicity of arsenic and widespread use of those medicines throughout the world. However, in previous studies the arsenic toxicity was usually overestimated by considering the total arsenic concentration only. This work investigated the total concentration, speciation and bioaccessibility of arsenic in 84 commonly used traditional Chinese patent medicines (CPMs) and Chinese herbal medicines (CHMs) to evaluate arsenic's potential health risks to human. Arsenic was found in all the CPMs and 88% of CHMs at concentrations ranging from 0.033 to 91,000mgkg^-1 and 0.012 to 6.6mgkg^-1, respectively. The bioaccessibility of arsenic varied significantly and was in the range of 0.21%-90% in the CPMs and 15%-96% in the CHMs, with inorganic arsenic as the predominant species. The average daily intake dose (ADD) and hazard quotient (HQ) of arsenic in most of medicines were within the safe limits, while in certain medicines, they exceeded the safe threshold level. These excesses remind us that the potential health risk by consumption of several medicines may not be negligible and more control and monitoring of arsenic in medicines should be carried out.

Bioaccessibility and health risk assessment of mercury in cinnabar containing Traditional Chinese Medicines

Cinnabar (α-HgS), has been formulated in Traditional Chinese Medicines (TCMs) for thousands of years. Since the total Hg content was accepted widely as the toxicity criteria, the safety alerts have been issued about the cinnabar containing TCMs for exceeding Hg limits. However, cinnabar is almost insoluble in water, the oral absorption is extremely low. Hence, it is not suitable to use the total Hg content alone to evaluate the toxicity of cinnabar containing TCMs. In instead, the bioaccessible Hg is a much reasonable safety indicator. In this study, bioaccessible Hg contents of 29 cinnabar containing TCMs were determined by cold vapor-atomic fluorescence spectrometry after in vitro extractions with the simulated gastrointestinal fluids, while the total Hg contents were determined after acid digestion. According to the daily dosages, the bioaccessible Hg exposures of these TCMs were evaluated, and most of them were within the permitted daily exposure set by the International Council for Harmonisation, demonstrating that these TCMs are safe when administrated following the instructions. However, the obtained results also suggested that the Hg exposure could also be influenced by the herbal ingredients in TCMs and the bioactivities in gastrointestinal tract, indicating the possible health risks after excessive or long-term medication of cinnabar containing TCMs. Considering the influencing factors of the Hg intakes after oral administration of cinnabar containing TCMs, the bioaccessible Hg exposure should be considered as a more rational criterion for evaluating the health risks than the total Hg content. Furthermore, precautions should also be taken to ensure safe usages of cinnabar containing TCMs from both the cinnabar contents and the processing procedures points of view, as well as the daily dosage regimen, for all of them are directly related with the bioaccessible Hg exposures.

Sources, distribution, bioavailability, toxicity, and risk assessment of heavy metal(loid)s in complementary medicines

The last few decades have seen the rise of alternative medical approaches including the use of herbal supplements, natural products, and traditional medicines, which are collectively known as 'Complementary medicines'. However, there are increasing concerns on the safety and health benefits of these medicines. One of the main hazards with the use of complementary medicines is the presence of heavy metal(loid)s such as arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg). This review deals with the characteristics of complementary medicines in terms of heavy metal(loid)s sources, distribution, bioavailability, toxicity, and human risk assessment. The heavy metal(loid)s in these medicines are derived from uptake by medicinal plants, cross-contamination during processing, and therapeutic input of metal(loid)s. This paper discusses the distribution of heavy metal(loid)s in these medicines, in terms of their nature, concentration, and speciation. The importance of determining bioavailability towards human health risk assessment was emphasized by the need to estimate daily intake of heavy metal(loid)s in complementary medicines. The review ends with selected case studies of heavy metal(loid) toxicity from complementary medicines with specific reference to As, Cd, Pb, and Hg. The future research opportunities mentioned in the conclusion of review will help researchers to explore new avenues, methodologies, and approaches to the issue of heavy metal(loid)s in complementary medicines, thereby generating new regulations and proposing fresh approach towards safe use of these medicines.

Comparative analysis of speciation and bioaccessibility of arsenic in rice grains and complementary medicines

In many countries, rice grains and complementary medicines are important sources of arsenic (As) consumption. The objective of this study was to compare the speciation and bioaccessibility of As in selected rice grains and complementary medicines. A number of rice grain samples, and a range of herbal and ayurvedic medicines were analyzed for total As, speciation of As using sequential fractionation and extended x-ray absorption fine structure (EXAFS) techniques, and bioaccessibility of As using an in vitro extraction test. The daily intake of As through the uptake of these As sources was compared with the safety guidelines for As. The results demonstrated higher levels of As in ayurvedic medicines compared to herbal medicines and rice grains. The sequential fractionation showed the dominance of organic-bound As species in rice grains and herbal medicines, however, inorganic-bound As species dominated the ayurvedic medicines. This implies that As is derived from plant uptake in herbal medicines and rice grains, and from inorganic mineral input in ayurvedic medicines. Arsenic bioaccessibility was higher in ayurvedic than herbal medicines and rice grains, suggesting that inorganic As added as a mineral therapeutic input is more bioaccessible than organic As species derived from plant uptake. This study also showed a positive relationship between soluble As fractions and bioaccessibility indicating that solubility is an important factor controlling bioaccessibility. The daily intake values for As as estimated by total As content are likely to exceed the safe threshold level in rice grains that are enriched with As.

Speciation and bioavailability of lead in complementary medicines

Complementary medicines have associated risks which include toxic heavy metal(loid) and pesticide contamination. The objective of this study was to examine the speciation and bioavailability of lead (Pb) in selected complementary medicines. Six herbal and six ayurvedic medicines were analysed for: (i) total heavy metal(loid) contents including arsenic (As), cadmium (Cd), Pb and mercury (Hg); (ii) speciation of Pb using sequential fractionation and extended x-ray absorption fine structure (EXAFS) techniques; and (iii) bioavailability of Pb using a physiologically-based in vitro extraction test (PBET). The daily intake of Pb through the uptake of these medicines was compared with the safety guidelines for Pb. The results indicated that generally ayurvedic medicines contained higher levels of heavy metal(loid)s than herbal medicines with the amount of Pb much higher than the other metal(loid)s. Sequential fractionation indicated that while organic-bound Pb species dominated the herbal medicines, inorganic-bound Pb species dominated the ayurvedic medicines. EXAFS data indicated the presence of various Pb species in ayurvedic medicines. This implies that Pb is derived from plant uptake and inorganic mineral input in herbal and ayurvedic medicines, respectively. Bioavailability of Pb was higher in ayurvedic than herbal medicines, indicating that Pb added as a mineral therapeutic input is more bioavailable than that derived from plant uptake. There was a positive relationship between soluble Pb fraction and bioavailability indicating that solubility is an important factor controlling bioavailability. The daily intake values for Pb as estimated by total and bioavailable metal(loid) contents are likely to exceed the safe threshold level in certain ayurvedic medicines. This research demonstrated that Pb toxicity is likely to result from the regular intake of these medicines which requires further investigation.

Estimation of bioaccessibility and potential human health risk of mercury in Chinese patent medicines

Mercury (Hg), mainly in cinnabar species, has been used in medicine for thousands of years in China, and worldwide concern has been raised on its toxicity. In this work, the amount of bioaccessible mercury in 16 Chinese patent medicines (CPMs) was measured by using an in vitro simulated digestion system, consisting of simulated gastric and intestinal fluid, to investigate the bioavailability of mercury in CPMs and evaluate its potential risk to human health. Total mercury and mercury in the gastrointestinal extracts were measured by inductively coupled plasma mass spectrometry (ICP-MS). The levels of total Hg in 16 CPMs ranged from not detected to 11.89 mg/g, with a mean value of 1.13 mg/g, while the extractable Hg ranged from not detected to 4.37 μg/g, with a mean value of 0.42 μg/g. Mercury bioaccessibility varied significantly in the investigated CPMs, depending on the ingredient. Compared to the CPMs without cinnabar (2.5%-30.9%), the percentage of mercury in the gastrointestinal supernatants for CPMs with cinnabar was quite a bit lower (0.037%). By comparing with the Food and Agricultural Organization/World Health Organization Joint Expert Committee on Food Additives (FAO/WHO) safety guideline, the average daily intake dose (ADD) of Hg in the medicines was then calculated to access the risk of mercury to human health from taking CPMs.

Bioaccessibility versus bioavailability of essential (Cu, Fe, Mn, and Zn) and toxic (Pb) elements from phyto hyperaccumulator Pistia stratiotes: potential risk of dietary intake

Aquatic weeds are widely used as animal feed in developing countries. However, information about element bioavailability from these plants is lacking. A combination of an in vitro method [physiologically based extraction test (PBET)] and an in vivo feeding trial was used in this study to investigate potential element bioaccessibility and estimated bioavailability of Pistia stratiotes (PS). Cu, Fe, Mn, Zn, and Pb concentrations in PS biomass, artificial gastrointestinal fluids, and rat tissues were determined using atomic absorption spectrometry with electrothermal atomization and inductively coupled plasma-atomic emission spectrometry. PS exhibited elevated Fe, Mn, and Pb levels. The PBET revealed high bioaccessibility of all monitored elements from PS biomass. The results of the in vivo trial were inconsistent with those of the PBET, because animals fed PS exhibited low levels of essential elements in the tissues. The consumption of a PS-supplemented diet significantly decreased total Fe levels and increased the total level of accumulation of Pb in exposed animals. Significantly reduced amounts of essential elements in the intestinal walls indicated a potential disruption in nutrient gastrointestinal absorption in animals fed PS.

Bioaccessibility of mercury in selected Ayurvedic medicines

Five Ayurvedic medicines with mercury concentrations of 85mg/kg and higher were characterized with respect to their speciation and their bioaccessibility. X-ray absorption spectroscopy revealed that the mercury in the Ayurvedic medicines was inorganic and best matched to cinnabar, even in samples that had been hypothesized to contain mercury through plant sources only. The bioaccessibility (bioaccessible concentrations and percent bioaccessibility) was measured using two methods: a two-phase physiologically based extraction test (PBET gastric, G and gastric+intestinal phase, GI); and the fed organic estimation human simulation test (FOREhST). The percent bioaccessibility of mercury in all Ayurvedic samples was very low (<5%), corresponding to the low solubility of cinnabar, but it increased with increasing dissolved organic carbon content of the bioaccessibility solutions (PBET-G<PBET-GI<FOREhST). Filtration of FOREhST solutions reduced the bioaccessible mercury concentrations to undetectable values for most of the Ayurvedic samples. Incorporation of percent relative bioaccessibility of mercury into risk calculations decreased daily intake estimates by 29-900 times, and reduced them to acceptable levels for three of the five medicines.

Determination of mercury in ayurvedic dietary supplements that are not rasa shastra using the hydra-C direct mercury analyzer

Mercury has been determined in Ayurvedic dietary supplements (Trifala, Trifala Guggulu, Turmeric, Mahasudarshan, Yograj, Shatawari, Hingwastika, Shatavari, and Shilajit) by inductively coupled plasma-mass spectrometry (ICP-MS) and direct mercury analysis using the Hydra-C direct mercury analyzer (Teledyne Leeman Labs Hudson, NH, USA). Similar results were obtained from the two methods, but the direct mercury analysis method was much faster and safer and required no microwave digestion (unlike ICP-MS). Levels of mercury ranged from 0.002 to 56 μg/g in samples of dietary supplements. Standard reference materials Ephedra 3240 and tomato leaves that were from the National Institute of Standard and Technology (NIST) and dogfish liver (DOLT3) that was from the Canadian Research Council were analyzed using Hydra-C method. Average mercury recoveries were 102% (RSD% 0.0018), 100% (RSD% 0.0009), and 101% (RSD% 0.0729), respectively. Hydra-C method Limit Of Quantitation was 0.5 ng.

Bioaccessibility of lead and arsenic in traditional Indian medicines

Arsenic and lead have been found in a number of traditional Ayurvedic medicines, and the practice of Rasa Shastra (combining herbs with metals, minerals and gems), or plant ingredients that contain these elements, may be possible sources. To obtain an estimate of arsenic and lead solubility in the human gastrointestinal tract, bioaccessibility of the two elements was measured in 42 medicines, using a physiologically-based extraction test. The test consisted of a gastric phase at pH 1.8 containing organic acids, pepsin and salt, followed by an intestinal phase, at pH 7 and containing bile and pancreatin. Arsenic speciation was measured in a subset of samples that had sufficiently high arsenic concentrations for the X-ray absorption near edge structure analysis used. Bioaccessible lead was found in 76% of samples, with a large range of bioaccessibility results, but only 29% of samples had bioaccessible arsenic. Lead bioaccessibility was high (close to 100%) in a medicine (Mahayograj Guggulu) that had been compounded with bhasmas (calcined minerals), including naga (lead) bhasma. For the samples in which arsenic speciation was measured, bioaccessible arsenic was correlated with the sum of As(V)-O and As(III)-O and negatively correlated with As-S. These results suggest that the bioaccessible species in the samples had been oxidized from assumed As-S raw medicinal ingredients (realgar, As(4)S(4), added to naga (lead) bhasma and As(III)-S species in plants). Consumption at recommended doses of all medicines with bioaccessibile lead or arsenic would lead to the exceedance of at least one standard for acceptable daily intake of toxic elements.

Use of ion-molecule reactions and methanol addition to improve arsenic determination in high chlorine food samples by DRC-ICP-MS

Direct determination of trace arsenic in high chlorine food samples by ICP-MS is complicated by the presence of ArCl(+) interferences, and the high first ionization energy of As (9.81 eV) also results in low analytical sensitivity in ICP-MS. In this work, two strategies based on ion-molecule reactions were successfully used to eliminate ArCl spectral interference in a dynamic reaction cell (DRC). The interference ion ((40)Ar(35)Cl(+)) was directly removed by the reaction with methane gas, and the background signal was reduced by up to 100-fold at m/z 75. Alternatively, by using molecule oxygen as the reaction gas, (75)As(+) was effectively converted to (75)As(16)O(+) that could be detected at m/z 91 where the background is low. The poor signal intensity of As or AsO was improved 3-4 times by addition of 4% methanol in the analyzed solutions. The limit of quantitation (LOQ) for (75)As (CH(4)-DRC method) and (75)As(16)O (O(2)-DRC method) was 0.8 and 0.3 ng g(-1) and the analytical results of seaweed and yellow croaker standard reference materials were in good agreement with the certified values. As the routine arsenic monitoring method in our laboratory, it was applied to the accuracy determination of 119 high chlorine food samples from eight different markets of Beijing.