Protective role of quercetin against hematotoxic and immunotoxic effects of furan in rats

Phenolic profile, acute and subacute oral toxicity of the aqueous extract from Moroccan Mentha longifolia L. aerial part in Swiss Albino mice model

ETHNOPHARMACOLOGICAL RELEVANCE

Mentha longifolia (L.) (Lamiaceae) is a native plant in Morocco, traditionally used in different countries to treat several disorders notably gastrointestinal illnesses, respiratory disorders, infectious diseases, inflammatory diseases, and menstrual problems. Robust scientific evidence has confirmed multiple pharmacological properties of M. longifolia including antihemolytic, anti-inflammatory, antibacterial, hepatoprotective, anti-cancer, antidiabetic, gastroprotective effect, and antispasmodic activity.

AIM OF THE STUDY

The current study aimed to determine the phytochemical profile and assess the toxic effect of an aqueous extract of the arial parts of M. longifolia in male and female Swiss albino mice during acute and subacute oral toxicity.

MATERIALS AND METHODS

High-performance Liquid Chromatography Diode Array Detector (HPLC-DAD) was used to provide qualitative and quantitative analyses of phenolic compounds of M. longifolia aqueous extract. In acute toxicity experiments, four distinct groups of mice (n = 5/group/sex) were administered Mentha longifolia aqueous extract at single oral dosages of 0.5; 1; 2; 4, and 8 g/kg BW given by gavage and intraperitoneal for up to 14 days. Regarding the subacute toxicity investigation, Swiss albino mice were given M. longifolia aqueous extract orally at dosages of 100; 500; and 1000 mg/kg BW daily for 28 days. Body weight is measured every 7 days and suggested biochemical and hematological parameters were quantified, at the finish of 28 days of daily administration, sections of the liver, kidney, and spleen were histologically evaluated for showing damage to organs.

RESULTS

The data of High-performance Liquid chromatography analysis revealed that M. longifolia aqueous extract was rich in interesting phytochemical compounds, mainly quercetin, and rutin, followed by a hydroxybenzoic acid-like syringic acid. Regarding the acute test in mice, no mortality or symptoms of toxicity were detected following oral administration with a single dose of M. longifolia aqueous extract at any dosage limit up to 4 g/kg, which was the no-observed side effect threshold (NOAEL). The mortality rate as well as acute toxicity of the M. longifolia aqueous extract delivered intraperitoneally, are increased progressively with increasing dosage. The non-observed adverse effect level (NOAEL) for the intraperitoneal dosage was 1 g/kg BW, and the lowest observed adverse effect level (LOAEL) was 2 g/kg BW, the estimated acute toxicity (LD50) of intraperitoneally given M. longifolia aqueous extract in mice was 4.800 g/kg BW. Concerning subacute examinations in mice, the M. longifolia aqueous extract did not induce substantial modifications in biochemical or hematological indicators, preserving a slight increase in creatinine and urea levels. At the end of the experiment, a histopathological examination of the kidneys, liver, and spleen revealed normal architecture, suggesting no morphological damage.

CONCLUSION

The data we obtained indicate that acute or subacute administration of Mentha longifolia aqueous extract is relatively non-toxic in male and female Swiss albino mice.

Effects of different levels of dried onion powder on nutrient digestibility, biochemical parameters, and nitrogen balance in Wistar albino rats with induced hyperuricemia

Introduction: Onions (Allium cepa L.) are excellent sources of bioactive compounds and phytochemicals such as allicin, quercetin, fisetin, and other sulfurous compounds. Therefore, our study aimed to investigate the effects of dried onion powder on growth performance, nitrogen balance, and biochemical parameters in Wistar albino rats with induced hyperuricemia. Methods: A total of 24 rats were randomly divided into four groups, with six in each group: HU (positive control) and HOT1, HOT2, and HOT3 groups, which received a diet containing onion powder at concentrations of 11.13, 14.84, and 18.61 g/100 g, respectively. Hyperuricemia was induced in rats by administering a new formulation intraperitoneally (250 mg/kg potassium oxonate) and orally (40 mg/kg potassium bromate) daily for 14 days. After confirmation of hyperuricemia induction, rats were fed with onion-treated diets with various concentrations of quercetin for 21 days. Results: Significant decreases (p ≤ 0.05) in serum uric acid, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, total bilirubin, total cholesterol, and low-density lipoprotein were observed. An increasing trend (p ≤ 0.05) in the levels of hemoglobin (Hb), white blood cell (WBC), red blood cell (RBC), and platelet count was observed. An improvement in the levels of serum high-density lipoprotein, triglycerides, blood urea nitrogen, serum creatinine, serum total protein and neutrophils, lymphocytes, and monocytes was observed. A positive progress (p ≤ 0.05) was observed in growth performance and nutrient digestibility. Conclusion: In conclusion, a significantly lower uric acid level was observed in rats fed with HOT2 diet. Based on the ratio of the surface area (human/rat), the best recommended dose of onion for the incidence and prevention of hyperuricemia is 189.95 g, corresponding to the dose of 204 mg/day of quercetin in humans.

Adverse outcome pathway exploration of furan-induced liver fibrosis in rats: Genotoxicity pathway or oxidative stress pathway through CYP2E1 activation?

Furan is a widespread endogenous contaminant in heat-processed foods that can accumulate rapidly in the food chain and has been widely detected in foods, such as wheat, bread, coffee, canned meat products, and baby food. Dietary exposure to this chemical may bring health risk. Furan is classified as a possible category 2B human carcinogen by the International Agency for Research on Cancer, with the liver as its primary target organ. Hepatic fibrosis is the most important nontumoral harmful effect of furan and also an important event in the carcinogenesis of furan. Although the specific mechanism of furan-induced liver fibrosis is still unclear, it may involve oxidative stress and genetic toxicity, in which the activation of cytochrome P450 2E1 (CYP2E1) may be the key event. Thus, we conducted a study using an integrating multi-endpoint genotoxicity platform in 120-day in vivo subchronic toxicity test in rats. Results showed that the rats with activated CYP2E1 exhibited DNA double-strand breaks in D4, gene mutations in D60, and increased expression of reactive oxygen species and nuclear factor erythroid 2-related factor 2 in D120. Necrosis, apoptosis, hepatic stellate cell activation, and fibrosis also occurred in the liver, suggesting that furan can independently affect liver fibrosis through oxidative stress and genotoxicity pathways. Point of Departure (PoD) was obtained by benchmark-dose (BMD) method to establish health-based guidance values. The human equivalent dose of PoD derived from BMDL05 was 2.26 μg/kg bw/d. The findings laid a foundation for the safety evaluation and risk assessment of furan and provided data for the further construction and improvement of the adverse outcome pathway network in liver fibrosis.

Furan promotes cytotoxic effects through DNA damage and cell apoptosis in Leydig cells

Furan is an organic chemical that can cause adverse effects on human health and is formed as a result of the thermal decomposition of many food components during cooking, storage, and processing techniques. Studies have shown that exposure to furan causes nephrotoxicity, hepatotoxicity, immunotoxicity, and reproductive toxicity. According to our current knowledge of the literature, the genotoxic mode of action of furan is highly controversial. The genotoxic effects of furan on the male reproductive system, however, have not been studied. In this study, the TM3 Leydig cell line was treated with 750, 1500, and 3000 μM concentrations of furan for 24 h. Following the completion of the exposure period, the cytotoxicity of furan in TM3 Leydig cells was assessed using a cell viability assay and a spectrophotometric measurement of lactate dehydrogenase (LDH) enzyme levels. The double fluorescence staining method was used to demonstrate furan-induced apoptosis, and DNA damage was shown using the micronucleus, comet, and chromosomal aberration assays. The result indicated that furan administration of Leydig cells resulted in an increase in structural chromosomal aberration, comet, and micronucleus formation, reduced cell viability, increased LDH activity, and a higher incidence of apoptotic cells. These findings revealed that furan induces DNA damage in TM3 Leydig cells, causing genotoxicity and DNA damage-induced cytotoxicity.

Quercetin Mitigates Oxidative Stress, Inflammation, Apoptosis, and Histopathological Alterations Induced by Chronic Titanium Dioxide Nanoparticle Exposure in the Rat Spleen

Titanium dioxide nanoparticles (nano-TiO2) have become widespread but are accompanied by various health concerns. Quercetin (QT), a naturally occurring flavonoid in fruits and vegetables, exhibits potent antioxidant properties. This research examined the toxic impacts of nano-TiO2 on the structure and function of the spleen in adult male rats and assessed the possible protective effects of QT. A set of randomly grouped rats was established, consisting of a control group, a QT group (50 mg/kg/day), a nano-TiO2 group (300 mg/kg/day), and a QT-nano-TiO2 group. These substances were orally administered to the respective groups for 90 days. Nano-TiO2 significantly induced oxidative stress in the spleen, leading to reduced levels of serum immunoglobulins. Additionally, there was a notable increase in the expression of apoptotic markers and proinflammatory cytokines. These biochemical disturbances were accompanied by morphological changes in the spleens of rats exposed to nano-TiO2. However, coadministration of QT and nano-TiO2 effectively mitigated most nano-TiO2-induced alterations in the spleen, including apoptotic and proinflammatory responses, antioxidant imbalance, serum immunoglobulin levels, and histopathological changes. It can be concluded that QT has the potential to function as a protective agent against the detrimental impacts of nano-TiO2 on the spleen by improving the antioxidant defense mechanism and modulating the apoptotic and inflammatory responses.

Neurotoxicity of furan in juvenile Wistar rats involves behavioral defects, microgliosis, astrogliosis and oxidative stress

Evidence suggests that furan, a widespread environmental and food contaminant, causes liver toxicity and cancer, but its implications in the brain are not well defined. We measured behavioral, glial, and biochemical responses in male juvenile rats exposed orally to 2.5, 5 and 10 mg/kg furan and vitamin E after 28 days. Furan-mediated hyperactivity peaked at 5 mg/kg and did not exacerbate at 10 mg/kg. Enhanced motor defect was also observed at 10 mg/kg. Furan-treated rats elicited inquisitive exploration but showed impaired working memory. Without compromising the blood-brain barrier, furan induced glial reactivity with enhanced phagocytic activity, characterized by parenchyma-wide microglial aggregation and proliferation, which switched from hyper-ramified to rod-like morphology with increasing doses. Furan altered the glutathione-S-transferase-driven enzymatic and non-enzymatic antioxidant defence systems differentially and dose-dependently across brain regions. Redox homeostasis was most perturbed in the striatum and least disrupted in hippocampus/cerebellum. Vitamin E supplementation attenuated exploratory hyperactivity and glial reactivity but did not affect impaired working memory and oxidative imbalance. Overall, sub-chronic exposure of juvenile rats to furan triggered glial reactivity and behavioral defects suggesting the brain's vulnerability during juvenile development to furan toxicity. It remains to be determined whether environmentally relevant furan concentrations interfere with critical brain developmental milestones.

Quercetin Alleviates the Immunotoxic Impact Mediated by Oxidative Stress and Inflammation Induced by Doxorubicin Exposure in Rats

Doxorubicin (DOX) is a chemotherapeutic agent against hematogenous and solid tumors with undesirable side effects including immunosuppression. Quercetin (QUR), a natural flavonoid abundant in fruits and vegetables, has a potent antioxidant activity. The aim of the current study was to assess the impact of QUR on DOX-induced hematological and immunological dysfunctions in a rodent model. Randomly grouped rats were treated as follows: control, QUR alone (50 mg/kg for 15 days per os), DOX alone (2.5 mg/kg I/P, three times a week, for two weeks), and co-treated rats with QUR for 15 days prior to and concomitantly with DOX (for two weeks), at the doses intended for groups two and three. DOX alone significantly disrupted the erythrogram and leukogram variables. Serum immunoglobulin (IgG, IgM, and IgE) levels and the activities of catalase (CAT) and superoxide dismutase (SOD) in spleen were declined. The DNA damage traits in spleen were elevated with an upregulation of the expression of the apoptotic markers (p53 and Caspase-3 genes) and the proinflammatory cytokines (IL-6 and TNF-α genes), while the expression of CAT gene was downregulated. These biochemical changes were accompanied by morphological changes in the spleen of DOX-treated rats. Co-treatment with QUR abated most of the DOX-mediated alterations in hematological variables, serum immunoglobulins, and spleen antioxidant status, pro-inflammatory and apoptotic responses, and histopathological alterations. In essence, these data suggest that QUR alleviated DOX-induced toxicities on the bone marrow, spleen, and antibody-producing cells. Supplementation of chemotherapy patients with QUR could circumvent the DOX-induced inflammation and immunotoxicity, and thus prevent chemotherapy failure.

Study of occupational exposure to brick kiln emissions on heavy metal burden, biochemical profile, cortisol level and reproductive health risks among female workers at Rawat, Pakistan

The present study was planned to understand the heavy metal burden and its possible actions in blood of occupational females working at brick kilns at Rawat, Pakistan. A total of 232 women were included in the study, of which 114 presented control subjects. Apart from collection of demographic data, fertility indicators and body mass index (BMI), blood was collected from subjects that was later used for the determination of heavy metal concentrations using atomic absorption spectroscopy and haematological profile. Blood was centrifuged and plasma was obtained and stored at - 20° to study biochemical variables (sodium dismutase, peroxidase, reactive oxygen species, thiobarbituric acid reactive species, protein estimation), lipid profile and cortisol concentrations among the two groups. Analysis of heavy metal in blood showed elevated levels of cadmium (3.09 ± 0.01 μg/dl), chromium (4.20 ± 0.02 μg/dl) and nickel (5.59 ± 0.03 μg/dl) in worker's group as compared with control. Increased platelet count; decreased antioxidant enzyme and increased oxidants level; increased total cholesterol, low-density lipoprotein (LDL) and triglyceride (TG); decreased total protein and high-density lipoprotein (HDL); and increased cortisol levels were evident among workers as compared with the control group. The study concluded that occupational workers experience increased heavy metals burden in blood and, therefore, pose a risk to human health by causing reduction in antioxidant enzymes concentration and increase in stress conditions.

Quercetin-induced amelioration of deltamethrin stress in freshwater teleost, Channa punctata: Multiple biomarker analysis

We aimed to ascertain whether ubiquitous plant-based polyphenolic flavonoid compound quercetin (Q) was capable of alleviating deltamethrin (DM) stress in a freshwater teleost, Channa punctata, with emphasis on levels of acetylcholinesterase (AChE), reduced glutathione (GSH), glutathione-S-transferase (GST), DNA/RNA contents and hematological parameters. We measured these parameters in various tissues of fish at 7 and 21 days of exposure to DM doses (0.03 and 0.15 μL L^-1), Q (0.14 g L^-1) and their combinations (0.03 μL DM L^-1 + 0.14 g Q L^-1 and 0.15 μL DM L^-1 + 0.14 g Q L^-1). Both the DM doses altered blood parameters, lowered DNA/RNA contents, AchE activities, GSH levels and augmented GST activities as a mark of neurotoxicity and oxidative stress in fish tissues. We found that 0.14 g L^-1 Q ameliorated oxidative stress and AchE inhibitory effects, recovered DM-induced nucleic acid damage and alterations in blood parameters, with some tissue specificity and in duration-dependent manner. Thus, the results indicated that Q was capable of neuroprotection and enhancing the function of antioxidants in fish, which could be predicted to be useful for providing better protection to fish under aquaculture settings with improved Q-rich diets. Through this study with multiple biomarkers in several tissues of fish, valuable information for devising better strategies regarding pesticide risk assessment was obtained and it was recognized that an appropriate dose of Q was essential for its better functioning.

Combination of quercetin and Adriamycin effectively suppresses the growth of refractory acute leukemia

The present study aimed to investigate the effect of combined treatment with quercetin and Adriamycin (doxorubicin) on the development of refractory acute leukemia. Primary leukemic cells were isolated from patients with refractory drug-resistant acute leukemia. The Cell Counting Kit-8 assay was used to detect the proliferation of cells treated with a range of doses of Adriamycin, quercetin and a combination of the two drugs. Non-irradiated mice were used to establish a T cell acute lymphoblastic leukemia (T-ALL) model, which was subsequently treated with Adriamycin, quercetin and a combination of the two drugs. The survival time was recorded, and white and red blood cells and platelets in mouse peripheral blood were counted. Superoxide dismutase (SOD) activity and malondialdehyde (MDA) content of cardiac tissues were measured as indicators of oxidative stress and damage. Proliferation of primary leukemic cells was reduced by Adriamycin depending on the dose (0.06, 0.6 or 6 µg/ml) and treatment duration (24, 48 or 72 h) compared with the vehicle treated group. Co-treatment with quercetin achieved a similar suppression of leukemic cell proliferation when a lower dose of Adriamycin (0.03, 0.3 or 3 µg/ml) was administered for the same duration. The survival of non-irradiated mice with T-ALL was improved by co-treatment with a high dose of Adriamycin and quercetin compared with either treatment alone. Compared with treatment with Adriamycin alone, the combined treatment with Adriamycin and quercetin significantly enhanced the SOD activity and reduced the MDA content in the heart. Therefore, quercetin may enhance the effects of Adriamycin on refractory acute leukemia.

Differential susceptibility of kidneys and livers to proliferative processes and transcriptional level of the genes encoding desmin, vimentin, connexin 43, and nestin in rats exposed to furan

In this study, we aimed to assess the differential toxic impact, induced by furan exposure, on the liver and kidney tissues by estimating reactive oxygen species (ROS) level, total antioxidant capacity (TAC), oxidative damage, and the tissue injury markers in a male rat model. To explain such impacts, 20 rats were assigned into two groups: a control group, where rats were administered corn oil as a vehicle, and a furan-administered group, where furan was orally administered to rats at a dose of 16 mg/kg b wt/day (five days per week over eight weeks). The transcriptional levels of intermediate filament proteins (desmin, vimentin, nestin, and connexin 43) were assessed by using quantitative real-time polymerase chain reaction (PCR), and the cell proliferation markers (proliferating cell nuclear antigen [PCNA] and proliferation-associated nuclear antigen [Ki-67]) were recognized by immunohistochemical analysis. Furthermore, the ultrastructural changes of liver and kidney were monitored using electron microscopy. Our findings showed that furan exposure could induce hepatic and renal damage to different extents. Furan can increase the ROS content, oxidative damage indices, and liver tissue injury indices but not kidney injury indices. Furthermore, it decreases the TAC in the serum of exposed rats. In addition, furan exposure was associated with changes in the mRNA expression pattern of intermediate filament proteins in both kidney and liver tissues. Moreover, furan enhances the expression of PCNA and Ki-67 in the liver tissues but not in the kidney tissues. The ultrastructure evaluation revealed the incidence of glomerular podocyte degeneration and hepatocyte injury. These results conclusively demonstrate that the deleterious effects of furan are caused by promoting fibrosis and hepatocyte proliferation in liver tissues and triggering podocyte injury in the kidney tissues.

Thermal processing food-related toxicants: a review

Heterocyclic aromatic amines, acrylamide, 5-hydroxymethylfurfural, furan, polycyclic aromatic hydrocarbons, nitrosamines, acrolein, chloropropanols and chloroesters are generated toxicants formed in some foodstuffs, mainly starchy and protein-rich food during thermal treatment such as frying, roasting and baking. The formation of these chemical compounds is associated with development of aromas, colors and flavors. One of the challenges facing the food industry today is to minimize these toxicants without adversely affecting the positive attributes of thermal processing. To achieve this objective, it is essential to have a detailed understanding of the mechanism of formation of these toxicants in processed foods. All reviewed toxicants in that paper are classified as probable, possible or potential human carcinogens and have been proven to be carcinogenic in animal studies. The purpose of that review is to summarize some of the most frequent occurring heat-generated food toxicants during conventional heating, their metabolism and carcinogenicity. Moreover, conventional and microwave heating were also compared as two different heat treatment methods, especially how they change food chemical composition and which thermal food toxicants are formed during specific method.

Effects of Astragalus polysaccharides (APS) and chitooligosaccharides (COS) on growth, immune response and disease resistance of juvenile largemouth bass, Micropterus salmoides

The effects of oral administration of Astragalus polysaccharides (APS) and chitooligosaccharides (COS), single or combined, on the growth performance, immunity and disease resistance of M. salmoides were investigated. Largemouth bass juvenile were divided into 4 groups and each group was fed with diets supplemented with or without immunostimulant for 8 weeks. After 8 weeks of feeding trial, five fish per tank were sampled for immunity determination, ten fish per tank were challenged by A. hydrophila. The results showed that the largemouth bass fed with two immunostimulants alone or in combination significantly enhanced the final weight and specific growth rate (SGR), decreased feed conversion ratio (FCR) (P < 0.05). However, there were no significant differences (P < 0.05) in specific growth rate (SGR) between dietary COS and dietary APS. In addition, both COS and APS upregulated respiratory burst activity (RBA), phagocytic activity (PA), lysozyme activity and superoxide dismutase (SOD) activity. Meanwhile, COS also exhibited a increase in total leukocyte count, nitric oxide (NO) content and inducible nitric oxide synthase (iNOS) activity compared to the control. When challenged with A. hydrophila, the mortality of groups fed with COS and/or APS was lower than the control (P < 0.05). Under the experimental conditions, dietary APS and COS had a synergistic effect on lysozme activity, iNOS activity, NO content and disease resistance of fish (P < 0.05).

Risks for public health related to the presence of furan and methylfurans in food

The European Commission asked EFSA for a scientific evaluation on the risk to human health of the presence of furan and methylfurans (2-methylfuran, 3-methylfuran and 2,5-dimethylfuran) in food. They are formed in foods during thermal processing and can co-occur. Furans are produced from several precursors such as ascorbic acid, amino acids, carbohydrates, unsaturated fatty acids and carotenoids, and are found in a variety of foods including coffee and canned and jarred foods. Regarding furan occurrence, 17,056 analytical results were used in the evaluation. No occurrence data were received on methylfurans. The highest exposures to furan were estimated for infants, mainly from ready-to-eat meals. Grains and grain-based products contribute most for toddlers, other children and adolescents. In adults, elderly and very elderly, coffee is the main contributor to dietary exposure. Furan is absorbed from the gastrointestinal tract and is found in highest amounts in the liver. It has a short half-life and is metabolised by cytochrome P450 2E1 (CYP2E1) to the reactive metabolite, cis-but-2-ene-1,4-dialdehyde (BDA). BDA can bind covalently to amino acids, proteins and DNA. Furan is hepatotoxic in rats and mice with cholangiofibrosis in rats and hepatocellular adenomas/carcinomas in mice being the most prominent effects. There is limited evidence of chromosomal damage in vivo and a lack of understanding of the underlying mechanism. Clear evidence for indirect mechanisms involved in carcinogenesis include oxidative stress, gene expression alterations, epigenetic changes, inflammation and increased cell proliferation. The CONTAM Panel used a margin of exposure (MOE) approach for the risk characterisation using as a reference point a benchmark dose lower confidence limit for a benchmark response of 10% of 0.064 mg/kg body weight (bw) per day for the incidence of cholangiofibrosis in the rat. The calculated MOEs indicate a health concern. This conclusion was supported by the calculated MOEs for the neoplastic effects.

Protective role of quercetin against manganese-induced injury in the liver, kidney, and lung; and hematological parameters in acute and subchronic rat models

Manganese (Mn) is an important mineral element required in trace amounts for development of the human body, while over- or chronic-exposure can cause serious organ toxicity. The current study was designed to evaluate the protective role of quercetin (Qct) against Mn-induced toxicity in the liver, kidney, lung, and hematological parameters in acute and subchronic rat models. Male Sprague Dawley rats were divided into control, Mn (100 mg/kg for acute model and 15 mg/kg for subchronic model), and Mn + Qct (25 and 50 mg/kg) groups in both acute and subchronic models. Our result revealed that Mn + Qct groups effectively reduced Mn-induced ALT, AST, and creatinine levels. However, Mn + Qct groups had effectively reversed Mn-induced alteration of complete blood count, including red blood cells, hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, platelets, and white blood cells. Meanwhile, the Mn + Qct groups had significantly decreased neutrophil and eosinophil and increased lymphocyte levels relative to the Mn group. Additionally, Mn + Qct groups showed a beneficial effect against Mn-induced macrophages and neutrophils. Our result demonstrated that Mn + Qct groups exhibited protective effects on Mn-induced alteration of GRP78, CHOP, and caspase-3 activities. Furthermore, histopathological observation showed that Mn + Qct groups effectively counteracted Mn-induced morphological change in the liver, kidney, and lung. Moreover, immunohistochemically Mn + Qct groups had significantly attenuated Mn-induced 8-oxo-2′-deoxyguanosine immunoreactivity. Our study suggests that Qct could be a substantially promising organ-protective agent against toxic Mn effects and perhaps against other toxic metal chemicals or drugs.