Thymol induces mitochondrial pathway-mediated apoptosis via ROS generation, macromolecular damage and SOD diminution in A549 cells

Dietary monoterpenoids and human health: Unlocking the potential for therapeutic use

Natural products are widely used in different aspects of our lives - from household cleaners and food production, via cosmetics and aromatherapy, to both alternative and traditional medicine. In our research group, we have recently described several monoterpenoids with potential in the antiviral and anticancer therapy by allosteric targeting of aryl hydrocarbon receptor (AhR). Prior to any practical application, biological effects on human organism must be taken in concern. This review article is focused on the biological effects of 5 monoterpenoids on the human health previously identified as AhR antagonists with a therapeutic potential as antiviral and anticancer agents. We have thoroughly described cytotoxic, anti-inflammatory, anti-proliferative, and anticancer effects, as well as known interactions with nuclear receptors. As clearly demonstrated, monoterpenoids in general represent almost an inexhaustible reservoir of natural compounds possessing the ability to influence, modulate and improve human health.

Exploration of selected monoterpenes as potential TRPC channel family modulator in lung cancer, an in-silico upshot

Lung cancer is still the most frequent cause of cancer-related death, accounting for nearly two million cases yearly. As cancer is a multifactorial disease, developing novel molecular therapeutics that can simultaneously target multiple associated cellular processes has become necessary. Ion channels are diverse regulators of cancer-related processes such as abnormal proliferation, invasion, migration, tumor progression, inhibition of apoptosis, and chemoresistance. Among the various families of ion channels, the transient receptor potential canonical channel family steps out in the context of lung cancer, as several members have been postulated as prognostic markers for lung cancer. Phytochemicals have been found to have health benefits in the treatment of a variety of diseases and disorders. Among phytochemicals, monoterpenes are effective in treating both the early and late stages of cancer. The molecular docking interaction analysis was conducted to evaluate the binding potential of selected monoterpenes with TRPC3, TRPC4, TRPC5, and TRPC6 involved in different phases of carcinogenesis. Amongst the selected monoterpenes, thymoquinone exhibited the highest binding energy of -6.7 kcal/mol against the TRPC4 channel, and all amino acid binding residues were similar to those of the known inhibitor for TRPC4. In addition, molecular-dynamic simulation results parameters, such as RMSD, RMSF, and Rg, indicated that thymoquinone did not impact the protein compactness and exhibited stability during the interaction. The average interaction energy between thymoquinone and TRPC4 protein was -26.85 kJ/mol. In-silico Drug-likeness and ADMET profiling indicated that thymoquinone is a druggable candidate with minimal toxicity. We propose further investigation and evaluation of thymoquinone for lead optimization and drug development.Communicated by Ramaswamy H. Sarma.

Synergistic induction of apoptosis in lung cancer cells through co-delivery of PLGA phytol/α-bisabolol nanoparticles

This study explored the potential of poly-(lactic-co-glycolic) acid (PLGA) nanoparticles to enhance the effectiveness of anticancer treatments through combination therapy with phytol and α-bisabolol. The encapsulation efficiency of the nanoparticles was investigated, highlighting the role of ionic interactions between the drugs and the polymer. Characterization of PLGA-Phy+Bis nanoparticles was carried out using DLS with zeta potential and HR-TEM for size determination. Spectrophotometric measurements evaluated the encapsulation efficiency, loading efficiency, and in vitro drug release. FTIR analysis assessed the chemical interactions between PLGA and the drug actives, ensuring nanoparticle stability. GC-MS was employed to analyze the chemical composition of drug-loaded PLGA nanocarriers. Cytotoxicity was evaluated via the MTT assay, while Annexin V-FITC/PI staining and western blot analysis confirmed apoptotic cell death. Additionally, toxicity tests were performed on L-132 cells and in vivo zebrafish embryos. The study demonstrates high encapsulation efficiency of PLGA-Phy+Bis nanoparticles, which exhibit monodispersity and sizes of 189.3±5nm (DLS) and 268±54 nm (HR-TEM). Spectrophotometric analysis confirmed efficient drug encapsulation and release control. FTIR analysis revealed nanoparticle structural stability without chemical interactions. MTT assay results demonstrated the promising anticancer potential of all the three nanoparticle types (PLGA-Phy, PLGA-Bis, and PLGA-Phy+Bis) against lung cancer cells. Apoptosis was confirmed through Annexin V-FITC/PI staining and western blot analysis, which also revealed changes in Bax and Bcl-2 protein expression. Furthermore, the nanoparticles exhibited non-toxicity in L-132 cells and zebrafish embryo toxicity tests. PLGA-Phy+Bis nanoparticles exhibited efficient encapsulation, controlled release, and low toxicity. Apoptosis induction in A549 cells and non-toxicity in healthy cells highlight their clinical potential.

Integration of clinical phenoms and metabolomics facilitates precision medicine for lung cancer

Lung cancer is a common malignancy that is frequently associated with systemic metabolic disorders. Early detection is pivotal to survival improvement. Although blood biomarkers have been used in its early diagnosis, missed diagnosis and misdiagnosis still exist due to the heterogeneity of lung cancer. Integration of multiple biomarkers or trans-omics results can improve the accuracy and reliability for lung cancer diagnosis. As metabolic reprogramming is a hallmark of lung cancer, metabolites, specifically lipids might be useful for lung cancer detection, yet systematic characterizations of metabolites in lung cancer are still incipient. The present study profiled the polar metabolome and lipidome in the plasma of lung cancer patients to construct an inclusive metabolomic atlas of lung cancer. A comprehensive analysis of lung cancer was also conducted combining metabolomics with clinical phenotypes. Furthermore, the differences in plasma lipid metabolites were compared and analyzed among different lung cancer subtypes. Alcohols, amides, and peptide metabolites were significantly increased in lung cancer, while carboxylic acids, hydrocarbons, and fatty acids were remarkably decreased. Lipid profiling revealed a significant increase in plasma levels of CER, PE, SM, and TAG in individuals with lung cancer as compared to those in healthy controls. Correlation analysis confirmed the association between a panel of metabolites and TAGs. Clinical trans-omics studies elucidated the complex correlations between lipidomic data and clinical phenotypes. The present study emphasized the clinical importance of lipidomics in lung cancer, which involves the correlation between metabolites and the expressions of other omics, ultimately influencing clinical phenotypes. This novel trans-omics network approach would facilitate the development of precision therapy for lung cancer.

Neuroprotective mechanism of ribisin A on H2O2-induced PC12 cell injury model

Ribisin A has been shown to have neurotrophic activity. The aim of this study was to evaluate the neuroprotective effect of ribisin A on injured PC12 cells and elucidate its mechanism. In this project, PC12 cells were induced by H2O2 to establish an injury model. After treatment with ribisin A, the neuroprotective mechanism of ribisin A was investigated by methyl tetrazolium (MTT) assay, Enzyme-linked immunosorbent assay (ELISA), flow cytometric analysis, fluorescent probe analysis, and western blot. We found that ribisin A decreased the rate of lactate dehydrogenase (LDH) release, increased cellular superoxide dismutase (SOD) level, decreased the levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), Ca2+ expression and reactive oxygen species (ROS). Moreover, ribisin A significantly increased mitochondrial membrane potential (MMP) and inhibited apoptosis of PC12 cells. Meanwhile, ribisin A activated the phosphorylation of ERK1/2 and its downstream molecule CREB by upregulating the expression of Trk A and Trk B, the upstream molecules of the ERK signaling pathway.

Comparative analysis of chemical profiles, antioxidant, antibacterial, and anticancer effects of essential oils of two Thymus species from Montenegro

The essential oils of Thymus vulgaris (TVEO) and Thymus serpyllum (TSEO) show different biological activities. The aim of the study was to evaluate the biological activities of TVEO and TSEO from Montenegro. The main components of TVEO were p-cymene (29.52%), thymol (22.8%) and linalool (4.73%) while the main components of TSEO were p-cymene (19.04%), geraniol (11,09%), linalool (9.16%), geranyl acetate (6.49%) and borneol (5.24%). Antioxidant activity determined via DPPH for TVEO was 4.49 and FRAP 1130.27, while for TSEO it was estimated that DPPH was 4.88 μL/mL and FRAP was 701.25 μmol FRAP/L. Both essential oils were active against all tested bacteria, with the highest level of sensitivity of E. coli with MIC of 1.5625 μL/mL. Essential oils showed strong cytotoxic effects on human cancer cell lines, with IC50 values ranging from 0.20 to 0.24 μL/mL for TVEO and from 0.32 to 0.49 μL/mL for TSEO. TVEO caused apoptosis in cervical adenocarcinoma HeLa cells through activation of caspase-3 and caspase-8, while TSEO caused apoptosis through caspase-3. EOs decreased levels of oxidative stress in normal MRC-5 cells. HeLa cells treated with TVEO had reduced MMP2 expression levels, while cells treated with TSEO had lowered MMP2 and MMP9 levels. The treatment of HeLa cells with TVEO increased the levels of miR-16 and miR-34a, indicating potential tumor-suppressive properties. Our findings suggest that Thymus essential oils may be considered as good candidates for further investigation as cancer-chemopreventive and cancer-therapeutic agents.

Hesperidin Methyl Chalcone reduces extracellular Aβ(25-35) peptide aggregation and fibrillation and also protects Neuro 2a cells from Aβ(25-35) induced neuronal dysfunction

In the present study, we evaluated the neuroprotective potential of Hesperidin Methyl Chalcone (HMC) against the neurotoxicity induced by Aβ(25-35) peptide. HMC demonstrated higher free-radical scavenging activity than Hesperidin in initial cell-free studies. Investigations using the fluorescent dye thioflavin T with Aβ(25-35) peptide showed that HMC has the ability to combat extracellular amyloid aggregation by possessing anti-aggregation property against oligomers and by disaggregating mature fibrils. Also, the results of the molecular simulation studies show that HMC ameliorated oligomer formation. Further, the anti-Alzheimer's property of HMC was investigated in in vitro cell conditions by pre-treating the neuro 2a (N2a) cells with HMC before inducing Aβ(25-35) toxicity. The findings demonstrate that HMC increased cell viability, reduced oxidative stress, prevented macromolecular damage, allayed mitochondrial dysfunction, and exhibited anticholinesterase activity. HMC also reduced Aβ induced neuronal cell death by modulating caspase-3 activity, Bax expression and Bcl2 overexpression, demonstrating that HMC pre-treatment reduced mitochondrial damage and intrinsic apoptosis induced by Aβ(25-35).In silico evaluation against potential AD targets reveal that HMC could be a potent inhibitor of BACE-1, inhibiting the formation of toxic Aβ peptides. Overall, the findings imply that the neuroprotective efficacy of HMC has high prospects for addressing a variety of pathogenic consequences caused by amyloid beta in AD situations and alleviating cognitive impairments.

Assessment of the in Vitro Antimelanoma Potential of Lippia microphylla Cham (Verbenaceae) Essential Oil

Essential oils stand out among natural products for their complex composition, frequently described in the literature with a range of biological effects. This study evaluated the cytotoxic activity against several human cancer cell lines of essential oils extracted from the leaves of Lippia microphylla (EO-LM) Cham. (Verbenaceae). The melanoma cell line SK-MEL-28 was the most sensitive to the EO-LM, presenting an IC50 of 33.38±1.16 μg/mL. Afterward, the effects of EO-LM on the cell cycle, induction of apoptosis, and production of reactive oxygen species (ROS) were evaluated. We stated a significant increase in the sub-G1 population, indicating apoptosis, later confirmed by an increase of SK-MEL-28 cells labeled with Annexin V-FITC and by the formation of apoptotic bodies and membrane blebs, observed by confocal microscopy. Additionally, EO-LM reduced the production of ROS, indicating antioxidant activity. Therefore, EO-LM exhibits anti-melanoma activity in vitro, suggesting its potential as an anticancer agent.

Induction of G0/G1 phase cell cycle arrest and apoptosis by thymol through ROS generation and caspase-9/-3 activation in breast and colorectal cancer cell lines

BACKGROUND

Cancer is a major malignancy and one of the leading causes of death; it calls for a proactive strategy for the cure. Herbs are reservoirs of novel chemical entities and their phytochemical exploration has contributed considerably to the discovery of new anticancer drugs. Thymol, a natural phenolic monoterpenoid, has been implicated with many medicinal properties, including anticancer ones. However, the anti-proliferative and apoptosis-inducing ability of thymol on MDA-MB-231 and HCT-8 cell lines has not been studied yet in detail, and hence this study was conceived.

MATERIALS AND METHODS

We studied the cytotoxicity, morphological alterations of the cell, oxidative stress, cell cycle modulation, apoptosis and expression of apoptosis-related proteins that ensued due to thymol treatment in these cancer cells.

RESULTS

Thymol inhibited the cell proliferation, altered the morphology of the cells, increased the intracellular ROS level, arrested the cells in G0/G1 phase, induced apoptosis, upregulated pro-apoptotic protein p53 expression, downregulated anti-apoptotic protein Bcl-xL expression, and activated caspase-9 and -3.

CONCLUSION

These findings elucidate that thymol induces apoptosis through the intrinsic pathway, in MDA-MB-231 breast and HCT-8 colorectal cancer cells through ROS generation and G0/G1 phase cell cycle arrest. This reiterates the broad-spectrum anti-tumor potential of thymol and provides an insight to study further to be developed into an anticancer drug.

Neuroprotective effects of PRG on Aβ25-35-induced cytotoxicity through activation of the ERK1/2 signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Phylloporia ribis (Schumach:Fr.)Ryvarden is a genus of needle Phellinus medicinal fungi, parasitic on the living rhizomes of hawthorn and pear trees. As a traditional Chinese medicine, Phylloporia ribis was used in folklore for long-term illness, weakness and memory loss in old age. Previous studies have shown that polysaccharides from Phylloporia ribis (PRG) significantly promoted synaptic growth in PC12 cells in a dose-dependent manner, exhibiting "NGF"-like neurotrophic activity. Aβ_25-35 damage to PC12 cells produced neurotoxicity and decreased cell survival, and PRG reduced the apoptosis rate, suggesting that PRG has neuroprotective effects. The studies confirmed that PRG had the potential to be a neuroprotective agent, but its neuroprotective mechanism remained unclear.

AIM OF THE STUDY

We aimed to elucidate the neuroprotective effects of PRG in an Aβ_25-35-induced Alzheimer's disease (AD) model.

MATERIALS AND METHODS

Highly-differentiated PC12 cells were treated with Aβ_25-35 (AD model) and PRG, and were assessed for cellular apoptosis, inflammatory factors, oxidative stress, and kinase phosphorylation.

RESULTS

The results showed that the PRG groups effectively inhibited the neurotoxicity, mainly manifested by inhibiting mitochondrial oxidative stress, attenuating neuroinflammatory responses, and improving mitochondrial energy metabolism, eventually resulting in higher cell survival. The expression of p-ERK, p-CREB and BDNF proteins was increased in the PRG groups compared to the model group, which confirmed that PRG reversed the inhibition of the ERK pathway.

CONCLUSION

We provide evidence for neuroprotection conferred by PRG and its mechanism by inhibiting ERK1/2 hyper-phosphorylation, prevention of mitochondrial stress, and subsequent prevention of apoptosis. The study highlights PRG as a promising candidate with neuroprotective effects, the potential of which can be harnessed for identifying novel therapeutic targets.

Metabolomics profiling in prediction of chemo-immunotherapy efficiency in advanced non-small cell lung cancer

Background

To explore potential metabolomics biomarker in predicting the efficiency of the chemo-immunotherapy in patients with advanced non-small cell lung cancer (NSCLC).

Methods

A total of 83 eligible patients were assigned to receive chemo-immunotherapy. Serum samples were prospectively collected before the treatment to perform metabolomics profiling analyses under the application of gas chromatography mass spectrometry (GC-MS). The key metabolites were identified using projection to latent structures discriminant analysis (PLS-DA). The key metabolites were used for predicting the chemo-immunotherapy efficiency in advanced NSCLC patients.

Results

Seven metabolites including pyruvate, threonine, alanine, urea, oxalate, elaidic acid and glutamate were identified as the key metabolites to the chemo-immunotherapy response. The receiver operating characteristic curves (AUC) were 0.79 (95% CI: 0.69-0.90), 0.60 (95% CI: 0.48-0.73), 0.69 (95% CI: 0.57-0.80), 0.63 (95% CI: 0.51-0.75), 0.60 (95% CI: 0.48-0.72), 0.56 (95% CI: 0.43-0.67), and 0.67 (95% CI: 0.55-0.80) for the key metabolites, respectively. A binary logistic regression was used to construct a combined biomarker model to improve the discriminating efficiency. The AUC was 0.86 (95% CI: 0.77-0.94) for the combined biomarker model. Pathway analyses showed that urea cycle, glucose-alanine cycle, glycine and serine metabolism, alanine metabolism, and glutamate metabolism were the key metabolic pathway to the chemo-immunotherapy response in patients with advanced NSCLC.

Conclusion

Metabolomics analyses of key metabolites and pathways revealed that GC-MS could be used to predict the efficiency of chemo-immunotherapy. Pyruvate, threonine, alanine, urea, oxalate, elaidic acid and glutamate played a central role in the metabolic of PD patients with advanced NSCLC.

Thymol has anticancer effects in U-87 human malignant glioblastoma cells

BACKGROUND

Thymol (2-isopropyl-5-methylphenol) is a colorless crystalline derivative of cymene, that possesses pleotropic pharmacological properties, including analgesic, antibacterial, antispasmodic, and anti-inflammatory activities. Thymol has also been recognized for its beneficial effect as an anti-tumor agent, but the precise mechanism for this has not been fully elucidated. We aimed to identifying whether thymol exerts anti-cancer activity in human U-87 malignant glioblastoma (GB) cells (U-87).

METHODS AND RESULTS

Cell viability and apoptosis was evaluated in U-87 cells treated with thymol at different concentrations. Reactive oxygen species (ROS) production, mRNA expressions of apoptosis-related genes and cell cycle characteristics were assessed. The cytotoxic activity of the co-exposure of thymol and temozolomide (TMZ) was also evaluated. The half-maximal inhibitory concentration (IC50) of thymol in the U-87 cells was 230 μM assessed at 24 h after exposure. Thymol did not exhibit any cytotoxic effects on normal L929 cells at this concentration. Thymol treatment increased the expression of Bax and p53, and also increased apoptotic cell death, and excessive generation of ROS. Moreover, the cytotoxic activity of thymol on the U-87 cells may be related to the arrest of the cell cycle at the G0/G1 interface. Combination therapy showed that the cytotoxic effects of thymol synergized with TMZ, and combined treatment had more cytotoxic potential compared to either of the agents alone.

CONCLUSIONS

Our data indicate the potential cytotoxic activities of thymol on U-87 cells. Further studies are required to evaluate the spectrum of the antitumor activity of thymol on GB cells.

A Narrative Review of the Antitumor Activity of Monoterpenes from Essential Oils: An Update

Monoterpenes are a group of natural products that have been widely studied due to their therapeutic potential against various pathologies. These compounds are abundant in the chemical composition of essential oils. Cancer is a term that covers more than 100 different types of malignant diseases and is among the leading causes of death in the world. Therefore, the search for new pharmacotherapeutic options applicable to cancer is urgent. In this review, studies on the antitumor activity of monoterpenes found in essential oils were selected, and botanical, chemical, and pharmacological aspects were discussed. The most investigated monoterpenes were carvacrol and linalool with highly significant in vitro and in vivo tumor inhibition in several types of cancers. The action mechanisms of these natural products are also presented and are wildly varied being apoptosis the most prevalent followed by cell cycle impairment, ROS production, autophagy, necroptosis, and others. The studies reported here confirm the antitumor properties of monoterpenes and their anticancer potential against various types of tumors, as demonstrated in in vitro and in vivo studies using various types of cancer cells and tumors in animal models. The data described serve as a reference for the advancement in the mechanistic studies of these compounds and in the preparation of synthetic derivatives or analogues with a better antitumor profile.

Newly Synthesized Thymol Derivative and Its Effect on Colorectal Cancer Cells

Thymol affects various types of tumor cell lines, including colorectal cancer cells. However, the hydrophobic properties of thymol prevent its wider use. Therefore, new derivatives (acetic acid thymol ester, thymol β-D-glucoside) have been synthesized with respect to hydrophilic properties. The cytotoxic effect of the new derivatives on the colorectal cancer cell lines HT-29 and HCT-116 was assessed via MTT assay. The genotoxic effect was determined by comet assay and micronucleus analysis. ROS production was evaluated using ROS-Glo™ H₂O₂ Assay. We confirmed that one of the thymol derivatives (acetic acid thymol ester) has the potential to have a cyto/genotoxic effect on colorectal cancer cells, even at much lower (IC₅₀~0.08 μg/mL) concentrations than standard thymol (IC₅₀~60 μg/mL) after 24 h of treatment. On the other side, the genotoxic effect of the second studied derivative-thymol β-D-glucoside was observed at a concentration of about 1000 μg/mL. The antiproliferative effect of studied derivatives of thymol on the colorectal cancer cell lines was found to be both dose- and time-dependent at 100 h. Moreover, thymol derivative-treated cells did not show any significantly increased rate of micronuclei formation. New derivatives of thymol significantly increased ROS production too. The results confirmed that the effect of the derivative on tumor cells depends on its chemical structure, but further detailed research is needed. However, thymol and its derivatives have great potential in the prevention and treatment of colorectal cancer, which remains one of the most common cancers in the world.

Traditional Herbal Medicine: A Potential Therapeutic Approach for Adjuvant Treatment of Non-small Cell Lung Cancer in the Future

Lung carcinoma is the primary reason for cancer-associated mortality, and it exhibits the highest mortality and incidence in developed and developing countries. Non-small cell lung cancer (NSCLC) and SCLC are the 2 main types of lung cancer, with NSCLC contributing to 85% of all lung carcinoma cases. Conventional treatment mainly involves surgery, chemoradiotherapy, and immunotherapy, but has a dismal prognosis for many patients. Therefore, identifying an effective adjuvant therapy is urgent. Historically, traditional herbal medicine has been an essential part of complementary and alternative medicine, due to its numerous targets, few side effects and substantial therapeutic benefits. In China and other East Asian countries, traditional herbal medicine is increasingly popular, and is highly accepted by patients as a clinical adjuvant therapy. Numerous studies have reported that herbal extracts and prescription medications are effective at combating tumors. It emphasizes that, by mainly regulating the P13K/AKT signaling pathway, the Wnt signaling pathway, and the NF-κB signaling pathway, herbal medicine induces apoptosis and inhibits the proliferation and migration of tumor cells. The present review discusses the anti-NSCLC mechanisms of herbal medicines and provides options for future adjuvant therapy in patients with NSCLC.

Oxidative stress and expression of inflammatory factors in lung tissue of acute mountain sickness rats

The aim of the present study was to investigate the changes in lung histomorphology and oxidative stress, as well as the expression of interleukin (IL)-17C and other inflammatory factors during acute mountain sickness (AMS) in male Sprague-Dawley rats and to explore the underlying mechanism. Rats were randomly divided into a control group (0 h) and three hypoxia stress groups, exposed to low-pressure oxygen storage at a simulated altitude of 6,000 m for 24, 48 and 72 h, respectively. Morphological changes in lung tissue were observed by hematoxylin and eosin staining under light microscopy and transmission electron microscopy. The expression of inflammatory factors IL-17C, nuclear factor-κB (NF-κB), IL-1β, IL-6 and tumor necrosis factor-α (TNF-α) in lung tissue was assessed by RNA sequencing and verified by reverse transcription-quantitative PCR (RT-qPCR) and western blotting (WB). Superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) enzyme activity and malondialdehyde (MDA) expression were also measured. Experimental groups were compared to the control group following 24, 48 and 72 h of hypoxic stress. Lung tissue suffered from different degrees of injury, and the damage was the most severe after 48 h of hypoxic stress. RNA sequencing data from the lung tissue of rats from each group suggested that the expression of IL-17C, NF-κB, IL-1β, IL-6, and TNF-α increased significantly after hypoxic stress. RT-qPCR and WB demonstrated that the expression of IL-17C and NF-κB increased significantly after hypoxia lasting 48 and 72 h. IL-1β expression increased significantly after hypoxia stress lasting 24 and 48 h, and the expressions of TNF-α and IL-6 increased significantly after hypoxia stress lasting 24, 48 and 72 h (P<0.01). The enzyme activity of SOD and GSH-Px decreased significantly after lasting 24, 48 and 72 h of hypoxia (P<0.01), and MDA increased significantly after hypoxic stress lasting 48 and 72 h (P<0.01). In conclusion, under hypoxic stress, rats quickly initiate oxidative stress and immune responses. However, with prolonged hypoxic stress time, excessive oxidative stress can further stimulate the immune system in vivo, and release a large quantity of inflammatory factors accumulating in the body. This, in turn, may lead to the occurrence of inflammatory storms and further damage the lung tissue resulting in AMS.

Application of three-dimensional Raman imaging to determination of the relationship between cellular localization of diesel exhaust particles and the toxicity

A diesel exhaust particle (DEP) is a type of particulate matter that is easily produced from combustion in a diesel power engine. It has been reported that DEPs can cause short- and long-term health problems. This is because DEPs are complex mixtures that are highly inhalable through the airways due to their small particle size. However, the relationship between intracellular localization of DEPs after their deposition in the lungs and the subsequent biological responses remains to be clarified. This is due to difficulties in distinguishing particles that are inside the cells from those that are outside. In this study, A549 human lung epithelial cells were exposed to DEPs at concentrations of 0, 25, 75, or 200 µg/mL for different periods, after that particles in the A549 cells were analyzed by three-dimensional (3D) images obtained from a Raman microscope. The cytotoxic effects of DEPs on the A549 cells were investigated by measuring cell viability, the levels of intracellular reactive oxygen species (ROS) and cell death. The Raman microscopy revealed that the particles invaded the A549 cells, and at a concentration of 200 µg/mL, they markedly decreased cell viability, increased intracellular ROS production, triggered late apoptosis/necrosis and induced nuclear damage. These results suggest that intracellular DEPs exposed at a high concentration may be highly toxic and can impair the viability of A549 cells. Furthermore, the 3D images from the Raman microscopy can be used to evaluate intracellular particle dynamics.

Antitumor Effects of Carvacrol and Thymol: A Systematic Review

Background: It is estimated that one in five people worldwide faces a diagnosis of a malignant neoplasm during their lifetime. Carvacrol and its isomer, thymol, are natural compounds that act against several diseases, including cancer. Thus, this systematic review aimed to examine and synthesize the knowledge on the antitumor effects of carvacrol and thymol.

Methods: A systematic literature search was carried out in the PubMed, Web of Science, Scopus and Lilacs databases in April 2020 (updated in March 2021) based on the PRISMA 2020 guidelines. The following combination of health descriptors, MeSH terms and their synonyms were used: carvacrol, thymol, antitumor, antineoplastic, anticancer, cytotoxicity, apoptosis, cell proliferation, in vitro and in vivo. To assess the risk of bias in in vivo studies, the SYRCLE Risk of Bias tool was used, and for in vitro studies, a modified version was used.

Results: A total of 1,170 records were identified, with 77 meeting the established criteria. The studies were published between 2003 and 2021, with 69 being in vitro and 10 in vivo. Forty-three used carvacrol, 19 thymol, and 15 studies tested both monoterpenes. It was attested that carvacrol and thymol induced apoptosis, cytotoxicity, cell cycle arrest, antimetastatic activity, and also displayed different antiproliferative effects and inhibition of signaling pathways (MAPKs and PI3K/AKT/mTOR).

Conclusions: Carvacrol and thymol exhibited antitumor and antiproliferative activity through several signaling pathways. In vitro, carvacrol appears to be more potent than thymol. However, further in vivo studies with robust methodology are required to define a standard and safe dose, determine their toxic or side effects, and clarify its exact mechanisms of action.

This systematic review was registered in the PROSPERO database (CRD42020176736) and the protocol is available at https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=176736.