Protocatechuic acid protects against hepatorenal toxicities in rats exposed to Furan

The protective effects of protocatechuic acid against natural and chemical toxicants: cellular and molecular mechanisms

Protocatechuic acid (PCA) is a water-soluble polyphenol compound that is extracted from certain fruits and plants or obtained from glucose fermentation. Several in vivo and in vitro studies have determined that PCA has protective effects against the toxicity of natural and chemical toxicants. We searched these articles in PubMed, Google Scholar, and Scopus with appropriate keywords from inception up to August 2023. Forty-nine studies were found about protective effects of PCA against drug toxicity, metal toxicity, toxins, chemical toxicants, and some other miscellaneous toxicants. PCA indicates these protective effects by suppression of oxidative stress, inflammation, and apoptosis. PCA reduces reactive oxygen/nitrogen species (RONS) and enhances the level of antioxidant parameters mainly through the activation of the Nrf-2 signaling pathway. PCA also decreases the levels of inflammatory mediators via downregulating the TLR-4-mediated IKBKB/NF-κB and MAPK/Erk signaling pathways. In addition, PCA inhibits apoptosis by lowering the expression of Bax, caspase-3, and caspase-9 along with enhancing the level of the antiapoptotic protein Bcl-2. Further evaluation, especially in humans, is necessary to confirm PCA as a potential therapeutic approach to intervene in such toxicities.

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.

A comprehensive review of furan in foods: From dietary exposures and in vivo metabolism to mitigation measures

Furan is a thermal food processing contaminant that is ubiquitous in various food products such as coffee, canned and jarred foods, and cereals. A comprehensive summary of research progress on furan is presented in this review, including discussion of (i) formation pathways, (ii) occurrence and dietary exposures, (iii) analytical techniques, (iv) toxicities, (v) metabolism and metabolites, (vi) risk assessment, (vii) potential biomarkers, and (viii) mitigation measures. Dietary exposure to furan varies among different countries and age groups. Furan acts through various toxicological pathways mediated by its primary metabolite, cis-2-butene-1,4-dial (BDA). BDA can readily react with glutathione, amino acids, biogenic amines, or nucleotides to form corresponding metabolites, some of which have been proposed as potential biomarkers of exposure to furan. Present risk assessment of furan mainly employed the margin of exposure approach. Given the widespread occurrence of furan in foods and its harmful health effects, mitigating furan levels in foods or exploring potential dietary supplements to protect against furan toxicity is necessary for the benefit of food safety and public health.

A biochemical and histology experimental approach to investigate the adverse effect of chronic lead acetate and dietary furan on rat lungs

Despite lead widespread environmental pollution, its effect on humans and livestock's respiratory systems remains inadequately investigated. Similarly, furan is industrially relevant with enormous environmental presence. Lead and furan can be ingested -via lead pipes contaminated water and heat-treated food respectively. Thus, humans are inadvertently exposed continuously. Lead toxicity is well studied, and furan have earned a position on the IARC's list of carcinogens. Here, we evaluate the effect of co-exposure to lead and furan on rat lungs. Thirty Wistar rats were grouped randomly into six cohorts (n = 6) consisting of a control group, furan alone group, lead acetate (PbAc) alone group and three other groups co-exposure to graded PbAc (1, 10 & 100 µg/L) alongside a constant furan (8 mg/kg) dose. After twenty-eight days, enzymatic and non-enzymatic antioxidant, oxidative stress and inflammatory biomarkers were biochemically evaluated. The ELISA-based technique was used to measure oxidative-DNA damage (8-OHG), tumour protein 53 (TP53) expressed and tumour necrotic factor-alpha (TNF-α) level. Dose-dependent increases (p < 0.05) in reactive oxygen and nitrogen species, malondialdehyde, nitric oxide, myeloperoxidase, TNF-α and TP53 level, with an associated decrease (p < 0.05) in enzymatic and non-enzymatic antioxidants were observed in the furan, PbAc and the co-treated rats relative to the control. In addition, PbAc and furan treatment impaired the histoarchitectural structures of rat lungs, exemplified by pro-inflammatory cell infiltration and trafficking into the bronchioles and alveolar spaces. Co-exposure to furan and PbAc may contribute to lung dysfunction via loss of redox balance, genomic damage/instability, inflammation and disrupted histoarchitectural features.

Influence of furan and lead co-exposure at environmentally relevant concentrations on neurobehavioral performance, redox-regulatory system and apoptotic responses in rats

Furan and lead are contaminants of global concern due to the potential public health threat associated with their exposure. Herein, the neurobehavioral performance, biochemical effects and histological alterations associated with co-exposure to furan (8 mg/kg) and lead acetate at low, environmentally realistic concentrations (1, 10 and 100 µg PbAc/L) for 28 uninterrupted days were investigated in rats. The results demonstrated that locomotor, motor and exploratory deficits associated with separate exposure to furan and lead was exacerbated in the co-exposed rats. Furan and lead co-exposure aggravated the marked decrease in acetylcholinesterase activity and antioxidant status, elevation in oxido-inflammatory stress indices and caspases activation in the cerebrum and cerebellum of exposed rats compared with control. Furan and lead co-exposure worsened neuronal degeneration as verified by histomorphometry and histochemical staining. Collectively, furan and lead acts together to exacerbate neurotoxicity via inhibition of cholinergic system, induction of oxido-inflammatory stress and caspases activation in rats.

Accidental lead in contaminated pipe-borne water and dietary furan intake perturbs rats' hepatorenal function altering oxidative, inflammatory, and apoptotic balance

Inadvertent exposure to furan and Pb is associated with hepatorenal abnormalities in humans and animals. It is perceived that these two chemical species may work in synergy to orchestrate liver and kidney damage. Against this background, we investigated the combined effect of furan and incremental lead (Pb) exposure on hepatorenal dysfunction. Wistar rats (n = 30; 150 g) were treated for 28 days accordingly: Control; FUR (8 mg/kg), PbAc (100 µg/L), FUR + PbAc₁ (8 mg/kg FUR + 1 µg/L PbAc); FUR + PbAc₁ (8 mg/kg FUR + 10 µg/L PbAc), and FUR + PbAc₁ (8 mg/kg FUR + 100 µg/L PbAc). Biomarkers of hepatorenal function, oxidative stress, inflammation, DNA damage, and apoptosis were examined. Furan and incrementally Pb exposure increased the levels of hepatorenal biomarkers and oxidative and pro-inflammatory mediators, including lipid peroxidation, reactive oxygen and nitrogen species, and interleukin-1 beta. Increased DNA damage, caspases- 9 and -3, and atypical histoarchitecture of the hepatorenal tissues exemplified furan and Pb treatment-related perturbations. Furthermore, the levels of antioxidants and IL-10 were also suppressed. Furan and Pb dose-dependently exacerbated hepatorenal derangements by altering the redox and inflammatory rheostats, worsened DNA damage, and related apoptotic onset that may potentiate hepatorenal disorders in humans and animals. The findings validate the synergistic effect of furan and Pb in the pathophysiology of kidney and liver disorders.

Caffeic acid protects against DNA damage, oxidative and inflammatory mediated toxicities, and upregulated caspases activation in the hepatorenal system of rats treated with aflatoxin B1

Aflatoxicosis can induce largescale toxicities in predisposed populations. Food fortification with adequate antioxidant sources may reduce the toxic burden from aflatoxicosis. We examined the individual and combined effect of Caffeic acid (CA) on the aflatoxin B₁ (AFB₁)-induced hepatic and renal injury in male rats. Five experimental rat cohort (n = 6) consisting of the control (2 mL/kg corn oil), AFB₁ alone (50 μg/kg), CA alone (40 mg/kg), AFB₁+CA₁ (50 μg/kg + 20 mg/kg) and AFB₁+CA₂ (50 μg/kg + 40 mg/kg) were so treated for 28 consecutive days. Upon sacrifices, diagnostic markers of hepatorenal functions, oxidative stress, inflammation, oxidative deoxyribonucleic acid -DNA-damage and apoptosis were analysed. Our results showed that CA reduced AFB₁-induced toxicities in rats' liver and kidneys by significantly increasing (p < 0.05) endogenous antioxidant and the anti-inflammatory IL-10 level. Caffeic acid simultaneously reduced hepatic and renal dysfunction biomarkers in the serum, oxidative stress, and lipid peroxidation levels. Besides, CA diminished reactive oxygen and nitrogen species, inflammatory nitric oxide levels, interleukin-1 β and the activities of xanthine oxidase and myeloperoxidase. Additionally, CA reduced DNA damage and caspase-mediated apoptotic responses and preserved the cytoarchitecture of rats' liver and kidneys treated with AFB₁. These data suggest that CA can be used as a food additive to mitigate AFB₁-induced toxicity in the examined organs.