β-carotene and retinol reduce benzo[a]pyrene-induced mutagenicity and oxidative stress via transcriptional modulation of xenobiotic metabolizing enzymes in human HepG2 cell line

The protective effects of medicinal plants against cigarette smoking: A comprehensive review

BACKGROUNDS

Cigarette smoking remains a pervasive and harmful habit, and it poses a significant public health concern globally. Tobacco smoke contains numerous toxicants and carcinogens that contribute to the incidence of various diseases, including respiratory ailments, cancer, and cardiovascular disorders. Over the past decade, there has been a growing interest in exploring natural remedies to mitigate the harmful effects of cigarette smoke (CS). Medicinal plants, with their rich phytochemical compositions, have emerged as potential sources of protective agents against CS-induced damage.

OBJECTIVES

The current review attempts to comprehensively review and provide a thorough analysis of the protective effects of medicinal plants, including ginseng, Aloe vera, Olea europaea, Zea mays, green tea, etc. against CS-related toxicities.

MATERIALS AND METHODS

A comprehensive research and compilation of existing literature were conducted. We conducted a literature search using the Web of Science, PubMed, Scopus, and Google Scholar. We selected articles published in English between 1987 and 2025. The search was performed using keywords including cigarette smoking, cigarette smokers, second-hand smokers, natural compounds, plant extracts, naturally derived products, natural resources, phytochemicals, and medicinal plants.

RESULTS

This review critically investigated recent literature focusing on the effects of medicinal plant extracts, essential oils, and isolated compounds on reducing the adverse consequences of CS exposure. These investigations encompassed several in vivo, in vitro, and clinical trials, clarifying the mechanisms underlying the protective effects of these plants. The notable antioxidant, anti-inflammatory, and detoxifying properties of these botanical interventions were also highlighted.

CONCLUSION

Collectively, this review emphasizes the potential of medicinal plants in alleviating the harmful effects of CS. The rich active constituents present in these plants offer various mechanisms that counteract oxidative stress, inflammation, and carcinogenesis induced by CS exposure. Further research is warranted to reveal the precise molecular mechanisms, derive dosing recommendations, and explore the efficacy of botanical interventions in large-scale clinical trials, ultimately improving public health outcomes and providing valuable insights for the smoking population worldwide.

Negative Association of Serum β-Cryptoxanthin With Benzene and Its Derivatives

OBJECTIVE

Benzene is widely recognized as a potential carcinogen. Furthermore, the deficiency of specific nutrients may render individuals more vulnerable to cancer. For instance, β-cryptoxanthin, which possesses anti-inflammatory, antioxidant, and anticancer properties, has been identified as one such nutrient. Elevated benzene levels and reduced β-cryptoxanthin levels are reportedly correlated with an augmented susceptibility to cancer. To date, whether these 2 substances are linked with one another in the above correlation is yet to be determined.

METHOD

This study included 1358 participants with data on the serum concentration of β-cryptoxanthin as well as benzene and its derivatives. The data were sourced from the 2003-2004 National Health and Nutrition Examination Survey, a cross-sectional survey of the noninstitutionalized US population. Headspace solid-phase microextraction with gas chromatography and mass spectrometry was used to measure serum benzene and its derivatives, while high-performance liquid chromatography using multiwavelength photodiode-array absorbance detection was employed to quantify serum β-cryptoxanthin.

RESULTS

In this study, male and female participants showed average β-cryptoxanthin levels of 9.10 ± 6.35 and 9.92 ± 8.95 ug/dL, respectively (p = 0.049). Styrene exhibited the strongest correlation with the change in β-cryptoxanthin concentration (β = -3.30, p for trend <0.001) upon comparing highest-quartile participants with those in the lowest quartile, followed by benzene (β = -2.95, p for trend <0.001), toluene (β = -2.90, p for trend <0.001), and ethylbenzene (β = -1.43, p for trend = 0.09). Subgroup analysis by sex displayed a statistically significant negative correlation of β-cryptoxanthin with benzene, styrene, and toluene in both the unadjusted and multivariate-adjusted models.

CONCLUSIONS

The sera of noninstitutionalized US individuals exhibit a negative association of β-cryptoxanthin levels with benzene and its derivatives. Styrene demonstrates the strongest link with a substantial decline in serum β-cryptoxanthin levels, followed by benzene, toluene, and ethylbenzene.

Levels of polycyclic aromatic hydrocarbons in edible and fried vegetable oil: a health risk assessment study

Polycyclic aromatic hydrocarbons (PAHs) are environmental chemicals that are formed due to incomplete combustion of the organic matters, or during heat treatment of the food. The objectives of the present study were first to estimate levels of the 15-priority PAHs in the edible vegetable oil (corn oil, sunflower oil, olive oil, and canola oil) collected from Egypt. Furthermore, the effect of heat treatment on the formation of PAHs in the canola oil was further examined. In addition, dietary intakes and cancer risk among Egyptian consumers were additionally calculated. The achieved results indicated presence of 15-priority PAHs in all examined oil samples. Canola oil had the highest residual concentrations of PAHs compared with the other tested oil species. Heat treatment of canola oil led to a drastic increase in the formed B[a]P (316.55%), total 2-PAHs (322.47%), total 4-PAHs (297.42%), total 8-PAHs (285.26%), and total 15-PAHs (443.32%), respectively. The incremental lifetime cancer risk among the Egyptian population is considered safe when was calculated for all examined oil samples.

Physiological significance of link between polycyclic aromatic hydrocarbons and serum nutritional biomarkers

It is well-known that exposure to polycyclic aromatic hydrocarbons (PAH) may cause adverse health impacts. However, there are few investigations assessing the association between PAH exposure and the nutritional status of the general population. Thus, the purpose of this investigation was to assess the correlation between PAH metabolites and nutritional biomarkers in the U.S. general population. From the 2003-2006 National Health and Nutrition Examination Survey, 4,545 eligible participants were included in this cross-sectional study. To assess PAH exposure, ten urinary PAH metabolites were measured. Eleven serum nutritional biomarkers including carotenoids and vitamins were measured. The association between PAH metabolites and serum nutritional biomarkers was investigated using multivariate linear regression models. Increased 2-hydroxyfluorene was inversely correlated with elven serum nutritional biomarkers: α-carotene (β = -0.529, p < 0.001), β-cryptoxanthin (β = -0.968, p < 0.001), cis-β carotene (β = -0.149, p < 0.001), lutein and zeaxanthin (β = -1.188, p < 0.001), retinyl palmitate (β = -0.145, p < 0.001), retinyl stearate (β = -0.025, p = 0.006), total lycopene (β = -1.074, p < 0.001), trans-β carotene (β = -2.268, p < 0.001), trans-lycopene (β = -0.466, p < 0.003), retinol (β = -0.694, p = 0.004) and 25-hydroxyvitamin D (β = -1.247, p = 0.007). Increased 3-hydroxyfluorene was inversely correlated with eleven serum nutritional biomarkers: α-carotene (β = -0.740, p < 0.001), β-cryptoxanthin (β = -1.377, p < 0.001), cis-β carotene (β = -0.205, p < 0.001), lutein and zeaxanthin (β = -1.521, p < 0.001), retinyl palmitate (β = -0.209, p < 0.001), retinyl stearate (β = -0.034, p = 0.014), total lycopene (β = -1.20, p = 0.007), trans-β carotene (β = -3.185, p < 0.001), trans-lycopene (β = -0.490, p = 0.039), retinol (β = -1.366, p < 0.001) and 25-hydroxyvitamin D (β = -2.483, p < 0.001). Increased 1-hydroxypyrene was inversely correlated with eight serum nutritional biomarkers: α-carotene (β = -0.601, p = 0.001), β-cryptoxanthin (β = -1.071, p = 0.001), cis-β carotene (β = -0.170, p = 0.001), lutein and zeaxanthin (β = -1.074, p < 0.001), retinyl palmitate (β = -0.214, p = 0.005), retinyl stearate (β = -0.041, p = 0.043), total lycopene (β = -1.664, p = 0.011) and retinol (β = -1.381, p = 0.011). These results demonstrate that PAH exposure is significantly correlated with decreased levels of serum nutritional biomarkers.

Change of benzo(a)pyrene during frying and its groove binding to calf thymus DNA

Benzo[a]pyrene (BaP), a prototype of polycyclic aromatic hydrocarbons (PAHs) with potential mutagenicity, toxicity and carcinogenicity, is ubiquitous in deep-fried foods. Herein, the changes in eight specific PAHs (PAH8) concentration in sunflower oil during frying were investigated by gas chromatography-triple quadrupole-mass spectrometry (GC-QqQ-MS). PAH8 concentrations in sunflower oil were 23.92-27.82 μg kg^-1 and increased with increasing frying time. The detected BaP levels were 3.64-4.00 μg kg^-1, exceeding the upper limit (2 μg kg^-1) set by European Union (EU), though below the limiting value (10 μg kg^-1) in China. The interaction between BaP and calf thymus DNA (ctDNA) was explored through various spectroscopic methods and molecular docking. Melting studies, denaturation experiments, ionic strength effects and viscosity measurements indicated that BaP interacted with ctDNA primarily via groove binding as evidenced by circular dichroism analysis and molecular docking. Further gel electrophoresis assays suggested that DNA was damaged at high levels of BaP.

A biochemical approach to the anti-inflammatory, antioxidant and antiapoptotic potential of beta-carotene as a protective agent against bromobenzene-induced hepatotoxicity in female Wistar albino rats

Bromobenzene is a compound which has contributed much in understanding the mechanisms involved in xenobiotic hepatotoxicity induced by drugs and environment pollutants. In the present study, the protective and ameliorative effect of beta-carotene was investigated against bromobenzene-induced hepatotoxicity and compared with silymarin, a standard hepatoprotective reference drug. Beta-carotene (10 mg/kg b.w. p.o.) was administered to the rats for 9 days before intragastric intubation of bromobenzene (10 mmol/kg b.w.). Liver marker enzymes (aspartate transaminase, alanine transaminase and alkaline phosphatase), total protein content, bilirubin, total cholesterol, high-density lipoproteins, triglycerides, antioxidant status (reduced glutathione, superoxide dismutase, catalase, glutathione-S-transferase and glutathione peroxidase) were assessed along with histopathological analysis. ELISA was performed for analysing the levels of cytokines such as TNF-α, IL-1β and IL-6 in serum and in the liver. Caspase-3, COX-2 and NF-κB were evaluated by Western blotting. Administration of bromobenzene resulted in elevated levels of liver marker enzymes, bilirubin, lipid peroxidation and cytokines but deterioration in total protein content, antioxidant levels and histopathological conditions. Pre-treatment with beta-carotene not only significantly decreased the levels of liver markers, lipid peroxidation and cytokines but also improved histo-architecture and increased antioxidant levels minimising oxidative stress, and reduced factors contributing to apoptosis. This significant reversal of the biochemical changes on pre-treatment with beta-carotene in comparison with rats administered with bromobenzene clearly demonstrates that beta-carotene possesses promising hepatoprotective effect through its antioxidant, anti-inflammatory and antiapoptotic activity and hence is suggested as a potential therapeutic agent for protection from bromobenzene.

Deoxynivalenol-induced alterations in the redox status of HepG2 cells: identification of lipid hydroperoxides, the role of Nrf2-Keap1 signaling, and protective effects of zinc

Deoxynivalenol (DON) is a type B trichothecenes that is widely contaminating human and animal foods, leading to several toxicological implications if ingested. Induction of oxidative stress and production of lipid peroxides were suggested to be the reasons for DON-induced cytotoxicity. However, detailed and comprehensive profiling of DON-related lipid hydroperoxides was not identified. Furthermore, the mechanisms behind DON-induced cytotoxicity and oxidative stress have received less attention. Zinc (Zn) is an essential element that has antioxidant activities; however, the protective effects of Zn against DON-induced adverse effects were not examined. Therefore, this study was undertaken to investigate DON-induced cytotoxicity and oxidative damage to human HepG2 cell lines. Furthermore, a quantitative estimation for the formed lipid hydroperoxides was conducted using LC-MS/MS. In addition, DON-induced transcriptomic changes on the inflammatory markers and antioxidant enzymes were quantitatively examined using qPCR. The protective effects of Zn against DON-induced cytotoxicity and oxidative stress, the formation of lipid hydroperoxides (LPOOH), and antioxidant status in HepG2 cells were investigated. Finally, the effects of DON and Zn on the Nrf2-Keap1 pathway were further explored. The achieved results indicated that DON caused significant cytotoxicity in HepG2 cells accompanied by significant oxidative damage and induction of the inflammatory markers. Identification of DON-related LPOOH revealed the formation of 22 LPOOH species including 14 phosphatidylcholine hydroperoxides, 5 triacylglycerol hydroperoxides, and 3 cholesteryl ester hydroperoxides. DON caused significant downregulation of Nrf2-regulated antioxidant enzymes. Zn administration led to significant protection of HepG2 cells against DON-induced adverse effects, probably via activation of the Nrf2-Keap1 pathway.

Dietary phytochemicals as the potential protectors against carcinogenesis and their role in cancer chemoprevention

Health-threatening consequences of carcinogen exposure are mediated via occurrence of electrophiles or reactive oxygen species. As a result, the accumulation of biomolecular damage leads to the cancer initiation, promotion or progression. Accordingly, there is an association between lifestyle factors including inappropriate diet or carcinogen formation during food processing, mainstream, second or third-hand tobacco smoke and other environmental or occupational carcinogens and malignant transformation. Nevertheless, increasing evidence supports the protective effects of naturally occurring phytochemicals against carcinogen exposure as well as carcinogenesis in general. Isolated phytochemicals or their mixtures present in the whole plant food demonstrate efficacy against malignancy induced by carcinogens widely spread in our environment. Phytochemicals also minimize the generation of carcinogenic substances during the processing of meat and meat products. Based on numerous data, selected phytochemicals or plant foods should be highly recommended to become a stable and regular part of the diet as the protectors against carcinogenesis.

Identification of cadmium-produced lipid hydroperoxides, transcriptomic changes in antioxidant enzymes, xenobiotic transporters, and pro-inflammatory markers in human breast cancer cells (MCF7) and protection with fat-soluble vitamins

Cadmium (Cd) is a toxic metal that is regarded as a metallohormone with estrogen-like properties. The present study aimed at identification of lipid hydroperoxides produced in human breast cancer (MCF7) exposed to cadmium (Cd) at environmentally relevant levels. Cd induced cytotoxicity and oxidative stress and produced a series of 26 lipid hydroperoxide species including 14 phosphatidylcholine hydroperoxides (PC-OOH), 9 triacylglycerol hydroperoxides (TG-OOH), and 3 cholesteryl ester hydroperoxides (CE-OOH). Among these hydroperoxides, PC34:2-OOH, PC34:3-OOH, TG60:14-OOH, TG48:5-OOH, TG60:15-OOH, and CE20:4-OOH were produced in a dose-dependent manner, suggesting these as possible biomarkers for Cd exposure in MCF7 cells. In addition, Cd led to significant decreases in the gene expressions of antioxidants, detoxification enzymes, and xenobiotic transporters. In a protection trial, co-exposure of MCF7 cells to fat-soluble vitamins including vitamin A, D, and E reduced Cd-induced cytotoxicity, lipid peroxidation, oxidative stress, and inflammatory responses. Fat-soluble vitamins upregulated antioxidant and detoxification enzymes, and xenobiotic transporters. Therefore, dietary supplementation of such micronutrients is recommended for people at risk for exposure to Cd.

Comparative transcriptomics and transcriptional regulation analysis of enhanced laccase production induced by co-culture of Pleurotus eryngii var. ferulae with Rhodotorula mucilaginosa

The co-culturing of Pleurotus eryngii var. ferulae and Rhodotorula mucilaginosa was confirmed in our previous studies to be an efficient strategy to improve laccase production by submerged fermentation. To determine the possible regulation principles underlying this behaviour, comparative transcriptomic analysis was performed on P. eryngii var. ferulae to investigate the differential expression of genes in co-culture. RNA-seq analysis showed that genes concerning xenobiotic biodegradation and expenditure of energy were upregulated. However, genes related to oxidative stress were downregulated. In addition, the transcription levels of laccase isoenzymes were not consistent in the co-culture system: 3 laccase genes (lacc1, lacc2, lacc12) were upregulated, and 3 laccase genes (lacc4, lacc6, lacc9) were downregulated. The enhancement in laccase activity can be due to upregulation of a laccase heterodimer encoded by the genes lacc2 and ssPOXA3a (or ssPOXA3b), whose expression levels were increased by 459% and 769% (or 585% for ssPOXA3b) compared with those of a control, respectively. β-Carotene produced by R. mucilaginosa upregulated the transcription of lacc2 only. Combining these results with an analysis of cis-acting responsive elements indicated that four transcription factors (TFs) had potential regulatory effects on the transcription of laccase genes. It was supposed that TFa regulated lacc transcription by binding with methyl jasmonate and heat shock response elements. The expression of TFb, TFc, and TFd was regulated by β-carotene. However, β-carotene had no effect on TFa expression. These results provide a possible mechanism for the regulation of laccase gene transcription in the co-culture system and are also beneficial for the future intensification of fungal laccase production.

Effects of Pyrene on Human Liver HepG2 Cells: Cytotoxicity, Oxidative Stress, and Transcriptomic Changes in Xenobiotic Metabolizing Enzymes and Inflammatory Markers with Protection Trial Using Lycopene

Pyrene is one of the major polycyclic aromatic hydrocarbons formed during heat treatment of meat and in car exhausts; however, few studies have investigated pyrene-induced adverse effects on human cell lines. This study aimed at the investigation of pyrene-induced cytotoxicity and oxidative damage in human liver HepG2 cells at environmentally relevant concentrations. Pyrene-induced changes in mRNA expression of xenobiotic metabolizing enzymes (XMEs), xenobiotic transporters, antioxidant enzymes, and inflammatory markers were investigated using real-time PCR. As a protection trial, the ameliorative effects of lycopene, a carotenoid abundantly found in tomato, were investigated. The possible mechanisms behind such effects were examined via studying the co exposure effects of pyrene and lycopene on regulatory elements including the aryl hydrocarbon receptor (Air) and elytroid 2-related factor 2 (RF). The achieved results indicated that pyrene caused significant cytotoxicity at 50 n, with a clear production of reactive oxygen species (ROS) in a dose-dependent manner. Pyrene upregulated mRNA expression of phase I enzymes including CYP1A1, 1A2, and CYP1B1 and inflammatory markers including TNFα and Cox2. However, pyrene significantly downregulated phase II enzymes, xenobiotic transporters, and antioxidant enzymes. Interestingly, lycopene significantly reduced pyrene-induced cytotoxicity and ROS production. Moreover, lycopene upregulated detoxification and antioxidant enzymes, probably via its regulatory effects on Air- and RF-dependent pathways.

Determination of polycyclic aromatic hydrocarbon content in heat-treated meat retailed in Egypt: Health risk assessment, benzo[a]pyrene induced mutagenicity and oxidative stress in human colon (CaCo-2) cells and protection using rosmarinic and ascorbic acids

This study was undertaken to estimate the concentrations of the formed polycyclic aromatic hydrocarbons (PAHs) in heat-treated (boiled, pan-fried and grilled) meats collected from Egypt. Dietary intakes and cancer risks of PAHs among Egyptian adults were calculated. Benzo[a]pyrene (B[a]P)-induced mutagenicity and oxidative stress in human colon (CaCo-2) cell line and mechanisms behind such effects were also investigated. Finally, protection trials using rosmarinic (RMA) and ascorbic acids (ASA) were carried out. The results indicated formation of PAHs at high levels in the heat-treated meats. Calculated incremental life time cancer risk among Egyptian adults were 7.05179E-07, 7.00604 E-06 and 1.86069 E-05 due to ingestion of boiled, pan-fried and grilled meats, respectively. B[a]P-exposed CaCo-2 cells had high abilities for mutagenicity (490.05 ± 21.37 His + revertants) and production of reactive oxygen species. RMA and ASA protected CaCo-2 cells via reduction of B[a]P-induced mutagenicity and oxidative stress and upregulation of phase II detoxification enzymes and xenobiotic transporters.

Pre-treatment with Beta Carotene Gives Protection Against Nephrotoxicity Induced by Bromobenzene via Modulation of Antioxidant System, Pro-inflammatory Cytokines and Pro-apoptotic Factors

Bromobenzene is an environmental toxin which causes hepatotoxicity, and the secondary metabolites on biotransformation cause nephrotoxicity. The objective of this study was to assess the alleviation of the nephrotoxic effect of bromobenzene by beta carotene in female Wistar albino rats. Beta carotene (10 mg/kg b.w.p.o.) was delivered orally to the rats for 9 days before bromobenzene (10 mM/kg b.w.p.o.) was intragastrically intubated. Kidney markers, antioxidant status and lipid peroxidation were evaluated. In addition, the levels of TNF-α, IL-6 and IL-1β were measured in serum and in kidney tissue homogenate using ELISA. Caspase, COX-2 and NF-κB were measured with the help of Western blotting. Histopathological analysis of the kidney was done for the control and experimental rats. Bromobenzene induction caused elevation in levels of creatinine, urea, uric acid, cytokines and lipid per oxidation along with deterioration in histological observations and antioxidant status. Pre-treatment with beta carotene significantly (*p < 0.05) normalised the levels of kidney markers and pro-inflammatory cytokines. It also reduced oxidative stress and lipid peroxidation, as shown by improved antioxidant status. The anti-apoptotic activity was evidenced by inhibition of protein expression of caspase, COX-2 and NF-κB. This significant reversal (*p < 0.05) of the above variations in comparison with the control group as noticed in the bromobenzene-administered rats demonstrates that beta carotene possesses promising nephroprotective effect through its antioxidant, anti-inflammatory and anti-apoptotic activity and therefore suggests its use as a potential therapeutic agent for protection from bromobenzene and hence environmental pollutant toxicity.

Environmental Chemical Contaminants in Food: Review of a Global Problem

Contamination by chemicals from the environment is a major global food safety issue, posing a serious threat to human health. These chemicals belong to many groups, including metals/metalloids, polycyclic aromatic hydrocarbons (PAHs), persistent organic pollutants (POPs), perfluorinated compounds (PFCs), pharmaceutical and personal care products (PPCPs), radioactive elements, electronic waste, plastics, and nanoparticles. Some of these occur naturally in the environment, whilst others are produced from anthropogenic sources. They may contaminate our food-crops, livestock, and seafood-and drinking water and exert adverse effects on our health. It is important to perform assessments of the associated potential risks. Monitoring contamination levels, enactment of control measures including remediation, and consideration of sociopolitical implications are vital to provide safer food globally.

Ecological Relevance of the Major Allelochemicals in Lycopersicon esculentum Roots and Exudates

Stigmasterol, bergapten, and α-tomatine were isolated from tomato roots. The preliminary phytotoxic activities of stigmasterol and α-tomatine were evaluated in a wheat-coleoptile bioassay, and α-tomatine was more active than stigmasterol. To confirm its phytotoxic activity, α-tomatine was tested on Lactuca sativa and two weeds ( Lolium perenne and Echinochloa crus-galli), and it was active in all cases. The stimulatory activities of α-tomatine and stigmasterol on parasitic-plant germination were also evaluated, and α-tomatine was found to be active on Phelipanche ramosa, a parasitic plant of tomato. α-Tomatine was identified in root exudates by LC-MS/MS. This confirms that α-tomatine is exuded by roots into the environment, where it could act as both an allelochemical and a stimulator of P. ramosa, a parasitic plant of tomato.