Capsaicin, a Tasty Free Radical Scavenger: Mechanism of Action and Kinetics

Polyphenols targeting multiple molecular targets and pathways for the treatment of vitiligo

Vitiligo, a pigmentary autoimmune disorder, is marked by the selective loss of melanocytes in the skin, leading to the appearance of depigmented patches. The principal pathological mechanism is the melanocyte destruction mediated by CD8+ T cells, modulated by oxidative stress and immune dysregulation. Vitiligo affects both physical health and psychological well-being, diminishing the quality of life. Polyphenols, naturally occurring compounds with diverse pharmacological properties, including antioxidant and anti-inflammatory activities, have demonstrated efficacy in managing various dermatological conditions through multiple pathways. This review provides a comprehensive analysis of vitiligo and the therapeutic potential of natural polyphenolic compounds. We examine the roles of various polyphenols in vitiligo management through antioxidant and immunomodulatory effects, melanogenesis promotion, and apoptosis reduction. The review underscores the need for further investigation into the precise molecular mechanisms of these compounds in vitiligo treatment and the exploration of their combination with current therapies to augment therapeutic outcomes.

PBAT is biodegradable but what about the toxicity of its biodegradation products?

CONTEXT

Poly(butylene adipate-co-terephthalate) (PBAT) is a biodegradable plastic. It was introduced to the plastics market in 1998 and since then has been widely used around the world. The main idea of this research is to perform quantum chemical calculations to study the potential toxicity of PBAT and its degradation products. We analyzed the electron transfer capacity to determine its potential toxicity. We found that biodegradable products formed with benzene rings are as good electron acceptors as PBAT and OOH•. Our results indicate that the biodegradation products are potentially as toxic as PBAT. This might explain why biodegradation products alter the photosynthetic system of plants and inhibit their growth. From this and other previous investigations, we can think that biodegradable plastics could represent a potential environmental risk.

METHODS

All DFT computations were performed using the Gaussian16 at M062x/6-311 + g(2d,p) level of theory without symmetry constraints. Electro-donating (ω-) and electro-accepting (ω +) powers were used as response functions.

Genetic Targets and Applications of Iron Chelators for Neurodegeneration with Brain Iron Accumulation

Neurodegeneration with brain iron accumulation (NBIA) is a group of neurodegenerative diseases that are typically caused by a monogenetic mutation, leading to development of disordered movement symptoms such as dystonia, hyperreflexia, etc. Brain iron accumulation can be diagnosed through MRI imaging and is hypothesized to be the cause of oxidative stress, leading to the degeneration of brain tissue. There are four main types of NBIA: pantothenate kinase-associated neurodegeneration (PKAN), PLA2G6-associated neurodegeneration (PLAN), mitochondrial membrane protein-associated neurodegeneration (MKAN), and beta-propeller protein-associated neurodegeneration (BPAN). There are no causative therapies for these diseases, but iron chelators have been shown to have potential toward treating NBIA. Three chelators are investigated in this Review: deferoxamine (DFO), desferasirox (DFS), and deferiprone (DFP). DFO has been investigated to treat neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD); however, dose-related toxicity in these studies, as well as in PKAN studies, have shown that the drug still requires more development before it can be applied toward NBIA cases. Iron chelation therapies other than the ones currently in clinical use have not yet reached clinical studies, but they may possess characteristics that would allow them to access the brain in ways that current chelators cannot. Intranasal formulations are an attractive dosage form to study for chelation therapy, as this method of delivery can bypass the blood-brain barrier and access the CNS. Gene therapy differs from iron chelation therapy as it is a causal treatment of the disease, whereas iron chelators only target the disease progression of NBIA. Because the pathophysiology of NBIA diseases is still unclear, future courses of action should be focused on causative treatment; however, iron chelation therapy is the current best course of action.

Theoretical exploration of the phenolic compounds' inhibition mechanism of heterocyclic aromatic amines in roasted beef patties by density functional theory

The ability of spices (bay leaf, star anise, and red pepper) and their characteristic phenolic compounds (quercetin, kaempferol, and capsaicin) to inhibit Heterocyclic aromatic amines (HAAs) in roasted beef patties were compared. Density functional theory (DFT) was used to reveal phenolic compounds interacting with HAAs-related intermediates and free radicals to explore possible inhibitory mechanisms for HAAs. 3 % red chili and 0.03 % capsaicin reduced the total HAAs content by 57.09 % and 68.79 %, respectively. DFT demonstrated that this was due to the stronger interaction between capsaicin and the β-carboline HAAs intermediate (Ebind = -32.95 kcal/mol). The interaction between quercetin and phenylacetaldehyde was found to be the strongest (Ebind = -17.47 kcal/mol). Additionally, DFT indicated that capsaicin reduced the carbonyl content by transferring hydrogen atoms (HAT) to eliminate HO·, HOO·, and carbon-centered alkyl radicals. This study provided a reference for the development of DFT in the control of HAAs.

Toxicity of persistent organic pollutants: a theoretical study

CONTEXT

Polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) are two families of persistent organic pollutants that are dangerous as they remain in the atmosphere for long periods and are toxic for humans and animals. They are found all over the world, including the penguins of Antarctica. One of the mechanisms that explains the toxicity of these compounds is related to oxidative stress. The main idea of this theoretical research is to use conceptual density functional theory as a theory of chemical reactivity to analyze the oxidative stress that PCBs and PBDEs can produce. The electron transfer properties as well as the interaction with DNA nitrogenous bases of nine PCBs and ten PBDEs found in Antarctic penguins are investigated. From this study, it can be concluded that compounds with more chlorine or bromine atoms are more oxidizing and produce more oxidative stress. These molecules also interact directly with the nitrogenous bases of DNA, forming hydrogen bonds, and this may be an explanation for the toxicity. Since quinone-type metabolites of PCBs and PBDEs can cause neurotoxicity, examples of quinones are also investigated. Condensed Fukui functions are included to analyze local reactivity. These results are important as the reactivity of these compounds helps to explain the toxicity of PCBs and PBDEs.

METHODS

All DFT computations were performed using Gaussian16 at M06-2x/6-311 + g(2d,p) level of theory without symmetry constraints. Electro-donating (ω-) and electro-accepting (ω +) powers were used as global response functions and condensed Fukui functions as local parameters of reactivity.

Evaluation of binding mechanism of dietary phytochemical, capsaicin, with human transferrin: targeting neurodegenerative diseases therapeutics

Human transferrin (htf) plays a crucial role in regulating the balance of iron within brain cells; any disruption directly contributes to the development of Neurodegenerative Diseases (NDs) and other related pathologies, especially Alzheimer's Disease (AD). In recent times, a transition towards natural compounds is evident to treat diseases and this shift is mainly attributed to their broad therapeutic potential along with minimal side effects. Capsaicin, a natural compound abundantly found in red and chili peppers, possess neuroprotective potential. The current work targets to decipher the interaction mechanism of capsaicin with htf using experimental and computational approaches. Molecular docking analysis revealed that capsaicin occupies the iron binding pocket of htf, with good binding affinity. Further, the binding mechanism was investigated atomistically using Molecular dynamic (MD) simulation approach. The results revealed no significant alterations in the structure of htf implying the stability of the complex. In silico observations were validated by fluorescence binding assay. Capsaicin binds to htf with a binding constant (K) of 3.99 × 106 M-1, implying the stability of the htf-capsaicin complex. This study lays a platform for potential applications of capsaicin in treatment of NDs in terms of iron homeostasis.

Therapeutic Potential of Capsaicin in Various Neurodegenerative Diseases with Special Focus on Nrf2 Signaling

Neurodegenerative disease is mainly characterized by the accumulation of misfolded proteins, contributing to mitochondrial impairments, increased production of proinflammatory cytokines and reactive oxygen species, and neuroinflammation resulting in synaptic loss and neuronal loss. These pathophysiological factors are a serious concern in the treatment of neurodegenerative diseases. Based on the symptoms of various neurodegenerative diseases, different treatments are available, but they have serious side effects and fail in clinical trials, too. Therefore, treatments for neurodegenerative diseases are still a challenge at present. Thus, it is important to study an alternative option. Capsaicin is a naturally occurring alkaloid found in capsicum. Besides the TRPV1 receptor activator in nociception, capsaicin showed a protective effect in brain-related disorders. Capsaicin also reduces the aggregation of misfolded proteins, improves mitochondrial function, and decreases ROS generation. Its antioxidant role is due to increased expression of an nrf2-mediated signaling pathway. Nrf2 is a nuclear erythroid 2-related factor, a transcription factor, which has a crucial role in maintaining the normal function of mitochondria and the cellular defense system against oxidative stress. Intriguingly, Nrf2 mediated pathway improved the upregulation of antioxidant genes and inhibition of microglial-induced inflammation, improved mitochondrial resilience and functions, leading to decreased ROS in neurodegenerative conditions, suggesting that Nrf2 activation could be a better therapeutic approach to target pathophysiology of neurodegenerative disease. Therefore, the present review has evaluated the potential role of capsaicin as a pharmacological agent for the treatment and management of various neurodegenerative diseases via the Nrf2-mediated signaling pathway.

Phytochemicals as Substances that Affect Astrogliosis and their Implications for the Management of Neurodegenerative Diseases

Astrocytes are a multifunctional subset of glial cells that are important in maintaining the health and function of the central nervous system (CNS). Reactive astrocytes may release inflammatory mediators, chemokines, and cytokines, as well as neurotrophic factors. There may be neuroprotective (e.g., cytokines, like IL-6 and TGF-b) and neurotoxic effects (e.g., IL-1β and TNF-a) associated with these molecules. In response to CNS pathologies, astrocytes go to a state called astrogliosis which produces diverse and heterogenic functions specific to the pathology. Astrogliosis has been linked to the progression of many neurodegenerative disorders. Phytochemicals are a large group of compounds derived from natural herbs with health benefits. This review will summarize how several phytochemicals affect neurodegenerative diseases (e.g., Alzheimer's disease, Huntington's disease, amyotrophic lateral sclerosis, and Parkinson's disease) in basic medical and clinical studies and how they might affect astrogliosis in the process.

A Systematic Review of the Effects of Capsaicin on Alzheimer's Disease

Alzheimer's Disease (AD) is a progressive neurodegenerative disorder characterised by cognitive impairment, and amyloid-β plaques and neurofibrillary tau tangles at neuropathology. Capsaicin is a spicy-tasting compound found in chili peppers, with anti-inflammatory, antioxidant, and possible neuroprotective properties. Capsaicin intake has been associated with greater cognitive function in humans, and attenuating aberrant tau hyperphosphorylation in a rat model of AD. This systematic review discusses the potential of capsaicin in improving AD pathology and symptoms. A systematic analysis was conducted on the effect of capsaicin on AD-associated molecular changes, cognitive and behaviour resulting in 11 studies employing rodents and/or cell cultures, which were appraised with the Cochrane Risk of Bias tool. Ten studies showed capsaicin attenuated tau deposition, apoptosis, and synaptic dysfunction; was only weakly effective on oxidative stress; and had conflicting effects on amyloid processing. Eight studies demonstrated improved spatial and working memory, learning, and emotional behaviours in rodents following capsaicin treatment. Overall, capsaicin showed promise in improving AD-associated molecular, cognitive, and behavioural changes in cellular and animal models, and further investigations are recommended to test the readily available bioactive, capsaicin, to treat AD.

Uncovering Novel Capsaicin Inhibitory Activity towards Human Carbonic Anhydrase Isoforms IX and XII by Combining In Silico and In Vitro Studies

Hot pepper (Capsicum annuum) represents one of the most widespread functional foods of the Mediterranean diet, and is associated with a reduced risk of developing cardiovascular disease, cancer, and mental disorders. In particular, its bioactive spicy molecules, named Capsaicinoids, exhibit polypharmacological properties. Among them, Capsaicin (trans-8-methyl-N-vanillyl-6-nonenamide) is the most studied and reported in variegated scientific contributions for its beneficial effects, often linked to mechanisms of action unrelated to the activation of Transient Receptor Potential Vanilloid 1 (TRPV1). In this study, we present the application of in silico methods to Capsaicin for evaluating its inhibitory activity against the tumor-associated human (h) expressed CA IX and XII. In vitro assays confirmed Capsaicin inhibitory activity towards the most relevant tumor-related hCA isoforms. In particular, the hCAs IX and XII showed an experimental K_I value of 0.28 μM and 0.064 μM, respectively. Then, an A549 model of non-small cell lung cancer, typically characterized by an elevated expression of hCA IX and XII, was employed to test the inhibitory effects of Capsaicin in vitro under both normoxic and hypoxic conditions. Finally, the migration assay revealed that Capsaicin [10 µM] inhibits cells from moving in the A549 cells model.

Protective effects of Capsicum fruits and their constituents on damage in TNF-α-stimulated human dermal fibroblasts

BACKGROUND

Antioxidant and anti-inflammatory effects of natural products on skin cells have been proved to be effective in improving skin damage. Capsicum species contain capsaicinoids that have antioxidant and anti-inflammatory properties, and various subspecies are cultivated. In this study, the effects of four Capsicum fruits and major constituents on oxidative stress and inflammatory reactions were measured using human dermal fibroblasts (HDFs) to verify their effects on skin damage.

RESULTS

The inhibitory effects of nitric oxide (NO), reactive oxygen species (ROS), and prostaglandin E₂ (PGE₂ ) by cucumber hot pepper, red pepper (RDP), Shishito pepper (SSP), and Cheongyang pepper were determined in HDFs. RDP and SSP inhibited the production of NO, ROS, and PGE₂ in tumor necrosis factor-alpha-stimulated HDFs. Additionally, SSP seeds restored tumor necrosis factor-alpha-induced increase in matrix metalloproteinase-1 and decreased procollagen I α1 (COLIA1). In high-performance liquid chromatography analysis of the capsaicinoids capsaicin (CAP) and dihydrocapsaicin (DHC), CAP was detected at a higher level than DHC in the peel and seeds of all four types of Capsicum fruits, and the total amount of capsaicinoids was the highest in SSP. CAP and DHC, which are major constituents of Capsicum fruits, also inhibited NO, ROS, and PGE₂ and restored matrix metalloproteinase-1 and procollagen I α1.

CONCLUSION

RDP and SSP were shown to have a significant protective effect on skin damage, including oxidative stress, inflammatory reactions, and reduction of collagens. Capsaicinoids CAP and DHC were proved as active constituents. This research may provide basic data for developing Capsicum fruits as ingredients to improve skin damage, such as inflammation and skin aging. © 2022 Society of Chemical Industry.

Curcumin and Capsaicin-Loaded Ag-Modified Mesoporous Silica Carriers: A New Alternative in Skin Treatment

Biologically active substances of natural origin offer a promising alternative in skin disease treatment in comparison to synthetic medications. The limiting factors for the efficient application of natural compounds, such as low water solubility and low bioavailability, can be easily overcome by the development of suitable delivery systems. In this study, the exchange with the template procedure was used for the preparation ofa spherical silver-modified mesoporous silica nanocarrier. The initial and drug-loaded formulations are fully characterized by different physico-chemical methods. The incipient wetness impregnation method used to load health-promoting agents, curcumin, and capsaicin in Ag-modified carriers separately or in combinationresulted in high loading efficiency (up to 33 wt.%). The interaction between drugs and carriers was studied by ATR-FTIR spectroscopy. The release experiments of both active substances from the developed formulations were studied in buffers with pH 5.5, and showed improved solubility. Radical scavenging activity and ferric-reducing antioxidant power assays were successfully used for the evaluation of the antiradical and antioxidant capacity of the curcumin or/and capsaicin loaded on mesoporous carriers. Formulations containing a mixture of curcumin and capsaicin were characterized bypotentiation of their antiproliferative effect against maligning cells, and it was confirmed that the system for simultaneous delivery of both drugs has lower IC50 values than the free substances.The antibacterial tests showed better activity of the obtained delivery systems in comparison with the pure curcumin and capsaicin. Considering the obtained results, it can be concluded that the obtained delivery systems are promising for potential dermal treatment.

Antioxidant and copper-chelating power of new molecules suggested as multiple target agents against Alzheimer's disease. A theoretical comparative study

In this study, the scavenging activity against OOH radicals and the copper-chelating ability of two new synthesized molecules (named L1 and L2) that can act as multiple target agents against Alzheimer's disease have been investigated at the density functional theory level. The pK_a and molar fractions at physiological pH have been predicted. The main antioxidant reaction mechanisms in lipid-like and water environments have been considered and the relative rate constants determined. The copper-chelating ability of the two compounds has also been explored at different coordination sites and computing the complexation kinetic constants. Results show the L₁ compound is a more effective radical scavenging and copper-chelating agent than L₂.

Antioxidant activity of eugenol and its acetyl and nitroderivatives: the role of quinone intermediates-a DFT approach of DPPH test

This work investigated the antioxidant potential of acetylated and nitrated eugenol derivatives through structural analysis and the mechanism of hydrogen atomic transfer (HAT) by density functional theory (DFT). The structures were optimized by the hybrid functional M06-2X with basis set 6-31 + G(d,p), and the HAT mechanism was evaluated with HO, HOO, CH₃O, DPPH radicals. In agreement with experimental data from previous studies, two steps of hydrogen transfer were tested. The thermodynamic data showed the need for two hydrogen atomic transfer steps from antioxidants, followed by the formation of p-quinomethanes (27, 28, and 29) to make the reaction spontaneous with DPPH. Furthermore, theoretical kinetic data showed that the preferred antioxidant site depends on the instability of the attacking radical and confirmed the antioxidant profile for eugenol (1, 4-allylbenzene-1,2-diol), and nitro-derivative 7 (5-allyl-3-nitrobenzene-1,2-diol) in the DPPH assay. Finally, this study showed that nitro compound 6 (4-allyl-2-methoxy-6-nitrophenol) also has anti-radical activity with smaller radicals but is not observed in the experiment due to structural characteristics and chemoselectivity of DPPH.

Capsaicin has potent anti-oxidative effects in vivo through a mechanism which is non-receptor mediated

Capsaicin (8-methyl-N-vanillyl-trans-6-nonenamide) is the active ingredient of chilli peppers and is responsible for the characteristic pungency. The ubiquitous human consumption of chilli peppers indicates their influence on human health. The effect of capsaicin through sensory neurons via TRPV1 activation has been well studied, but its non-neuronal effects are still not extensively explored. The purpose of this study was to investigate the in vivo antioxidant effect of capsaicin on erythrocytes of male Wistar rats. Markers of oxidative stress in blood were determined by assessing the plasma total antioxidant potential, activity of plasma membrane redox system, intracellular glutathione (GSH) level, ROS level, protein oxidation and lipid peroxidation. Results of this study suggest a significant protective effect of capsaicin against oxidative stress by enhancing FRAP, GSH level, PMRS activity and ameliorating ROS, MDA, PCO and AOPP.

Application of Nanoparticles in the Treatment of Lung Cancer With Emphasis on Receptors

Lung cancer is one of the malignant tumors that has seen the most rapid growth in terms of morbidity and mortality in recent years, posing the biggest threat to people’s health and lives. In recent years, the nano-drug loading system has made significant progress in the detection, diagnosis, and treatment of lung cancer. Nanomaterials are used to specifically target tumor tissue to minimize therapeutic adverse effects and increase bioavailability. It is achieved primarily through two mechanisms: passive targeting, which entails the use of enhanced penetration and retention (EPR) effect, and active targeting, which entails the loading recognition ligands for tumor marker molecules onto nanomaterials. However, it has been demonstrated that the EPR effect is effective in rodents but not in humans. Taking this into consideration, researchers paid significant attention to the active targeting nano-drug loading system. Additionally, it has been demonstrated to have a higher affinity and specificity for tumor cells. In this review, it describes the development of research into active targeted nano-drug delivery systems for lung cancer treatment from the receptors’ or targets’ perspective. We anticipate that this study will help biomedical researchers use nanoparticles (NPs) to treat lung cancer by providing more and novel drug delivery strategies or solid ligands.

New insights into the competition between antioxidant activities and pro-oxidant risks of rosmarinic acid

Direct and indirect antioxidant activities of rosmarinic acid (RA) based on HOO˙/CH3OO˙ radical scavenging and Fe(iii)/Fe(ii) ion chelation were theoretically studied using density functional theory at the M05-2X/6-311++G(2df,2p) level of theory. First, four antioxidant mechanisms including hydrogen atom transfer (HAT), radical adduct formation (RAF), proton loss (PL) and single electron transfer (SET) were investigated in water and pentyl ethanoate (PEA) phases. Regarding the free radical scavenging mechanism, HAT plays a decisive role with overall rate coefficients of 1.84 × 103 M-1 s-1 (HOO˙) and 4.49 × 103 M-1 s-1 (CH3OO˙) in water. In contrast to PL, RAF and especially SET processes, the HAT reaction in PEA is slightly more favorable than that in water. Second, the [Fe(iii)(H2O)6]3+ and [Fe(ii)(H2O)6]2+ ion chelating processes in an aqueous phase are both favorable and spontaneous especially at the O5, site-1, and site-2 positions with large negative Δr G 0 values and great formation constant K f. Finally, the pro-oxidant risk of RA- was also considered via the Fe(iii)-to-Fe(ii) complex reduction process, which may initiate Fenton-like reactions forming reactive HO˙ radicals. As a result, RA- does not enhance the reduction process when ascorbate anions are present as reducing agents, whereas the pro-oxidant risk becomes remarkable when superoxide anions are found. The results encourage further attempts to verify the speculation using more powerful research implementations of the antioxidant activities of rosmarinic acid in relationship with its possible pro-oxidant risks.

Radical Scavenging Potential of the Phenothiazine Scaffold: A Computational Analysis

The reactivity of phenothiazine (PS), phenoselenazine (PSE), and phenotellurazine (PTE) with different reactive oxygen species (ROS) has been studied using density functional theory (DFT) in combination with the QM-ORSA (Quantum Mechanics-based Test for Overall Free Radical Scavenging Activity) protocol for an accurate kinetic rate calculation. Four radical scavenging mechanisms have been screened, namely hydrogen atom transfer (HAT), radical adduct formation (RAF), single electron transfer (SET), and the direct oxidation of the chalcogen atom. The chosen ROS are HO. , HOO. , and CH3 OO. . PS, PSE, and PTE exhibit an excellent antioxidant activity in water regardless of the ROS due to their characteristic diffusion-controlled regime processes. For the HO. radical, the primary active reaction mechanism is, for all antioxidants, RAF. But, for HOO. and CH3 OO. , the dominant mechanism strongly depends on the antioxidant: HAT for PS and PSE, and SET for PTE. The scavenging efficiency decreases dramatically in lipid environment and remains only significant (via RAF) for the most reactive radical (HO. ). Therefore, PS, PSE, and PTE are excellent antioxidant molecules, especially in aqueous, physiological environments where they are active against a broad spectrum of harmful radicals. There is no advantage or significant difference in the scavenging efficiency when changing the chalcogen since the reactivity mainly derives from the amino hydrogen and the aromatic sites.

Capsaicin inhibits HIF-1α accumulation through suppression of mitochondrial respiration in lung cancer cells

Hypoxia inducible factor (HIF)-1α is an important transcription factor regulating cancer metabolism in hypoxic environment. Capsaicin is known to inhibit hypoxia-induced HIF activity in lung cancer. Hence, in this study we tried to elucidate its inhibitory mechanism of action. In lung cancer cells, including H1299, H23, A549, and H2009 cells, capsaicin inhibited cell growth and HIF activation. Under hypoxic conditions, capsaicin reduced the accumulation of HIF-1α protein and the expression of its target genes, including pyruvate dehydrogenase kinase 1 (PDK1) and glucose transporter 1 (GLUT1), with no effect on overall HIF-1α mRNA levels in the H1299 cells. In addition, capsaicin increased intracellular oxygen levels by suppressing mitochondrial respiration, resulting in a reduction of HIF-1α accumulation. Furthermore, mitochondrial ATP production was reduced by capsaicin through the inhibition of mitochondrial respiration in the H1299, H23, A549, and H2009 cells. These results indicate that capsaicin potentially exhibits anticancer therapeutic effects in lung cancer under hypoxic conditions.

Acetaminophen degradation by hydroxyl and organic radicals in the peracetic acid-based advanced oxidation processes: Theoretical calculation and toxicity assessment

The research on the mechanisms and kinetics of radical oxidation in peracetic acid-based advanced oxidation processes was relatively limited. In this work, HO^• and organic radicals mediated reactions of acetaminophen (ACT) were investigated, and the reactivities of important organic radicals (CH₃COO^• and CH₃COOO^•) were calculated. The results showed that initiated reaction rate constants of ACT are in the order: CH₃COO^• (5.44 × 10¹⁰ M^-1 s^-1) > HO^• (7.07 × 10⁹ M^-1 s^-1) > CH₃O^{• (}1.57 × 10⁷ M^-1 s^-1) > CH₃COOO^• (3.65 × 10⁵ M^-1 s^-1) >> ^•CH₃ (5.17 × 10² M^-1 s^-1) > CH₃C^•O (1.17 × 10² M^-1 s^-1) > CH₃OO^• (11.80 M^-1 s^-1). HO^•, CH₃COO^• and CH₃COOO^• play important roles in ACT degradation. CH₃COO^• is another important radical in the hydroxylation of aromatic compounds in addition to HO^•. Reaction rate constants of CH₃COO^• and aromatic compounds are 1.40 × 10⁶ - 6.25 × 10¹⁰ M^-1 s^-1 with addition as the dominant pathway. CH₃COOO^• has high reactivity to phenolate and aniline only among the studied aromatic compounds, and it was more selective than CH₃COO^•. CH₃COO^•-mediated hydroxylation of aromatic compounds could produce their hydroxylated products with higher toxicity.

Natural Methoxyphenol Compounds: Antimicrobial Activity against Foodborne Pathogens and Food Spoilage Bacteria, and Role in Antioxidant Processes

The antibacterial and antioxidant activities of three methoxyphenol phytometabolites, eugenol, capsaicin, and vanillin, were determined. The in vitro antimicrobial potential was tested on three common foodborne pathogens (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus) and three food spoilage bacteria (Shewanella putrefaciens, Brochothrix thermosphacta, and Lactobacillus plantarum). The antioxidant assays were carried out for studying the free radical scavenging capacity and the anti-lipoperoxidant activity. The results showed that eugenol and capsaicin were the most active against both pathogens and spoilage bacteria. S. aureus was one of the most affected strains (median concentration of growth inhibition: IC50 eugenol = 0.75 mM; IC50 capsaicin = 0.68 mM; IC50 vanillin = 1.38 mM). All phytochemicals slightly inhibited the growth of L. plantarum. Eugenol was the most active molecule in the antioxidant assays. Only in the oxygen radical absorbing capacity (ORAC) test did vanillin show an antioxidant activity comparable to eugenol (eugenol ORAC value = 2.12 ± 0.08; vanillin ORAC value = 1.81 ± 0.19). This study, comparing the antimicrobial and antioxidant activities of three guaiacol derivatives, enhances their use in future applications as food additives for contrasting both common pathogens and spoilage bacteria and for improving the shelf life of preserved food.

Capsaicin affects macrophage anti-inflammatory activity via the MAPK and NF-κB signaling pathways

Capsaicin, the main constituent in chili, is an extremely spicy vanillin alkaloid and is found in several Capsicum species in China. Traditionally, it has been used to treat inflammatory diseases such as allergic rhinitis, neuralgia after shingles, refractory female urethral syndrome, spontaneous recalcitrant anal pruritus, and solid tumors. Constant stimulation of the body by inflammatory factors can lead to chronic inflammation. Capsaicin possesses anti-inflammatory activity; however, the underlying mechanism is unknown. We investigated the effect of capsaicin on the secretion of macrophage inflammatory factors in a lipopolysaccharide-induced inflammation model using 56 healthy, SPF grade, BALB/c mice. To this end, mice peritoneal macrophages were isolated and stimulated with lipopolysaccharide (1 μg/mL) and capsaicin (25, 50, 75, or 100 μg/mL) for 24 h. At all concentrations tested, capsaicin significantly promoted the phagocytosis of neutral red dye by macrophages. Furthermore, the gene expression and secretion of inflammatory cytokines significantly increased after induction with lipopolysaccharide (P<0.01); the interleukin (IL)-6 level was 204 μg/mL, tumor necrosis factor (TNF)-α level was 860 μg/mL, and nitric oxide (NO) level was 19.8 μg/mL. However, the treatment with capsaicin reduced their levels (P<0.01) and protein expression of lipopolysaccharide-induced extracellular signal-related kinase 1/2 and p65 (P<0.05). Overall, capsaicin reduced the secretion of inflammatory cytokines (P<0.01), interleukins, TNF-α (P<0.01), and NO by inhibiting the nuclear factor-kappa B and microtubule-associated protein kinase signaling pathways, and thereby reduced lipopolysaccharide-induced inflammatory response in macrophages.

Are thymol, rosefuran, terpinolene and umbelliferone good scavengers of peroxyl radicals?

DFT-based computational calculations have been used to investigate the hydroperoxyl radical scavenging activity of four essential oil constituents namely thymol (Thy), rosefuran (Ros), terpinolene (Ter), and umbelliferone (Umb). Different reaction mechanisms including formal hydrogen transfer (FHT), radical adduct formation (RAF), sequential proton loss electron transfer (SPLET), and sequential electron transfer proton transfer (SETPT) have been examined in the gas phase and physiological environments. It was found that the HOO radical scavenging activity of these compounds is strongly influenced by the environment, which becomes more important in water than pentyl ethanoate. According to the overall reaction rate constants, the phenolic compounds Thy and Umb are predicted to exhibit excellent activity in aqueous solution. Umb with an overall rate constant of 1.44 × 10⁸M^-1s^-1 at physiological pH is among the best HOO radical scavengers in water with activity comparable to that of caffeic acid, higher than those of ascorbic acid, guaiacol and eugenol, and much higher than that of Trolox.

Free radical scavenging activity of newly designed sesamol derivatives

Recently proposed derivatives of sesamol as better oxidants than the parent molecule are predicted to react faster, with several orders larger rate constants than sesamol itself.

Capsaicin, a Powerful •OH-Inactivating Ligand

Oxidative conditions are frequently enhanced by the presence of redox metal ions. In this study, the role of capsaicin (8-methyl-N-vanillyl-6-nonenamide, CAP) in copper-induced oxidative stress was investigated using density functional theory simulations. It was found that CAP has the capability to chelate Cu(II), leading to complexes that are harder to reduce than free Cu(II). CAP fully turns off the Cu(II) reduction by Asc⁻, and slows down the reduction in this cation by O₂^•−. Therefore, CAP is proposed as an ^•OH-inactivating ligand by impeding the reduction in metal ions (OIL-1), hindering the production of ^•OH via Fenton-like reactions, at physiological pH. CAP is also predicted to be an excellent antioxidant as a scavenger of ^•OH, yielded through Fenton-like reactions (OIL-2). The reactions between CAP-Cu(II) chelates and ^•OH were estimated to be diffusion-limited. Thus, these chelates are capable of deactivating this dangerous radical immediately after being formed by Fenton-like reactions.

Capsaicin and Gut Microbiota in Health and Disease

Capsaicin is a widespread spice known for its analgesic qualities. Although a comprehensive body of evidence suggests pleiotropic benefits of capsaicin, including anti-inflammatory, antioxidant, anti-proliferative, metabolic, or cardioprotective effects, it is frequently avoided due to reported digestive side-effects. As the gut bacterial profile is strongly linked to diet and capsaicin displays modulatory effects on gut microbiota, a new hypothesis has recently emerged about its possible applicability against widespread pathologies, such as metabolic and inflammatory diseases. The present review explores the capsaicin–microbiota crosstalk and capsaicin effect on dysbiosis, and illustrates the intimate mechanisms that underlie its action in preventing the onset or development of pathologies like obesity, diabetes, or inflammatory bowel diseases. A possible antimicrobial property of capsaicin, mediated by the beneficial alteration of microbiota, is also discussed. However, as data are coming mostly from experimental models, caution is needed in translating these findings to humans.

Electrochemical behaviour of piperine. Comparison with control antioxidants

Piperine, as the most abundant alkaloid in pepper, gained a lot of attention for possible antioxidant and therapeutic properties. Electrochemical techniques were applied to widely evaluate the redox behavior of piperine by comparison to that of well-known antioxidants: ascorbic acid, protocatechuic acid, syringic acid, tyrosine and capsaicin used as controls. Also, electrochemistry was involved in an innovative way to investigate the potential antioxidant properties of piperine combined with different in vitro peroxidation and reducing assays: (i) 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH) scavenging; (ii) 2,2,6,6-tetramethylpiperidinyl-1-oxy (TEMPO) scavenging; (iii) ferric ions (Fe³⁺) reducing power; (iv) hydrogen peroxide (H₂O₂) scavenging. Results show that piperine readily reacts with highly oxidizing radicals and bind redox-active metal ions in a similar manner as antioxidants used as model.

Therapeutic potential of targeting MKK3-p38 axis with Capsaicin for Nasopharyngeal Carcinoma

Background: Capsaicin is an active compound found in plants of the Capsicum genus; it has a range of therapeutic benefits, including anti-tumor effects. Here we aimed to delineate the inhibitory effects of capsaicin on nasopharyngeal carcinoma (NPC). Methods: The anti-cancer effects of capsaicin were confirmed in NPC cell lines and xenograft mouse models, using CCK-8, clonogenic, wound-healing, transwell migration and invasion assays. Co-immunoprecipitation, western blotting and pull-down assays were used to determine the effects of capsaicin on the MKK3-p38 axis. Cell proliferation and EMT marker expression were monitored in MKK3 knockdown (KD) or over-expression NPC cell lines treated with or without capsaicin. Finally, immunohistochemistry was performed on NPC specimens from NPC patients (n = 132) and the clinical relevance was analyzed. Results: Capsaicin inhibited cell proliferation, mobility and promoted apoptosis in NPC cells. Then we found that capsaicin directly targets p38 for dephosphorylation. As such, MKK3-induced p38 activation was inhibited by capsaicin. Furthermore, we found that capsaicin-induced inhibition of cell motility was mediated by fucokinase. Xenograft models demonstrated the inhibitory effects of capsaicin treatment on NPC tumor growth in vivo, and analysis of clinical NPC samples confirmed that MKK3 phosphorylation was associated with NPC tumor growth and lymphoid node metastasis. Conclusions: The MKK3-p38 axis represents a potential therapeutic target for capsaicin. MKK3 phosphorylation might serve as a biomarker to identify NPC patients most likely to benefit from adjunctive capsaicin treatment.

Capsaicin—the major bioactive ingredient of chili peppers: bio-efficacy and delivery systems

The mechanisms of bio-efficacy of capsaicin and delivery systems with enhanced bioavailability were reviewed.

Major Depressive Disorder and Oxidative Stress: In Silico Investigation of Fluoxetine Activity against ROS

Major depressive disorder is a psychiatric disease having approximately a 20% lifetime prevalence in adults in the United States (U.S.), as reported by Hasin et al. in JAMA Psichiatry 2018 75, 336–346. Symptoms include low mood, anhedonia, decreased energy, alteration in appetite and weight, irritability, sleep disturbances, and cognitive deficits. Comorbidity is frequent, and patients show decreased social functioning and a high mortality rate. Environmental and genetic factors favor the development of depression, but the mechanisms by which stress negatively impacts on the brain are still not fully understood. Several recent works, mainly published during the last five years, aim at investigating the correlation between treatment with fluoxetine, a non-tricyclic antidepressant drug, and the amelioration of oxidative stress. In this work, the antioxidant activity of fluoxetine was investigated using a computational protocol based on the density functional theory approach. Particularly, the scavenging of five radicals (HO•, HOO•, CH3OO•, CH2=CHOO•, and CH3O•) was considered, focusing on hydrogen atom transfer (HAT) and radical adduct formation (RAF) mechanisms. Thermodynamic as well as kinetic aspects are discussed, and, for completeness, two metabolites of fluoxetine and serotonin, whose extracellular concentration is enhanced by fluoxetine, are included in our analysis. Indeed, fluoxetine may act as a radical scavenger, and exhibits selectivity for HO• and CH3O•, but is inefficient toward peroxyl radicals. In contrast, the radical scavenging efficiency of serotonin, which has been demonstrated in vitro, is significant, and this supports the idea of an indirect antioxidant efficiency of fluoxetine.

How Does Pyridoxamine Inhibit the Formation of Advanced Glycation End Products? The Role of Its Primary Antioxidant Activity

Pyridoxamine, one of the natural forms of vitamin B6, is known to be an effective inhibitor of the formation of advanced glycation end products (AGEs), which are closely related to various human diseases. Pyridoxamine forms stable complexes with metal ions that catalyze the oxidative reactions taking place in the advanced stages of the protein glycation cascade. It also reacts with reactive carbonyl compounds generated as byproducts of protein glycation, thereby preventing further protein damage. We applied Density Functional Theory to study the primary antioxidant activity of pyridoxamine towards three oxygen-centered radicals (•OOH, •OOCH3 and •OCH3) to find out whether this activity may also play a crucial role in the context of protein glycation inhibition. Our results show that, at physiological pH, pyridoxamine can trap the •OCH3 radical, in both aqueous and lipidic media, with rate constants in the diffusion limit (>1.0 × 108 M - 1 s - 1 ). The quickest pathways involve the transfer of the hydrogen atoms from the protonated pyridine nitrogen, the protonated amino group or the phenolic group. Its reactivity towards •OOH and •OOCH3 is smaller, but pyridoxamine can still scavenge them with moderate rate constants in aqueous media. Since reactive oxygen species are also involved in the formation of AGEs, these results highlight that the antioxidant capacity of pyridoxamine is also relevant to explain its inhibitory role on the glycation process.

The Mediterranean Diet as source of bioactive compounds with multi-targeting anti-cancer profile

Many bioactive agents have been extracted from plants or belong to functional foods and have been considered in the treatment of serious and multifactorial diseases, such as cancer. In particular, this review is focused on the anti-cancer properties owned by several natural products typically from the Mediterranean area. In some regions of the South of Italy, a lower cancer incidence has been observed. There is increasing evidence that adherence to a Mediterranean dietary pattern correlates with reduced risk of several cancer types. This could be mainly attributed to the typical lifestyle aspects of the Mediterranean diet, such as high consumption of fruit and vegetables. In this review, the main natural products of the Mediterranean area are discussed, with particular attention on their anti-cancer properties endowed with multi-target profiles.

A facile approach for fabricating CD44-targeted delivery of hyaluronic acid-functionalized PCL nanoparticles in urethane-induced lung cancer: Bcl-2, MMP-9, caspase-9, and BAX as potential markers

Lung carcinoma ranks highest in cancer-related death (about 20% of total cancer deaths) due to poor prognosis and lack of efficient management therapy. Owing to the lack of effective therapeutic approaches, survival rate of less than 5 years persists over the years among non-small cell lung cancer (NSCLC) patients. Capsaicin (CAP) is well reported for its antiproliferative and antioxidant properties in various literature but lacks an appropriate delivery carrier. The present study was aimed to develop CAP-loaded hyaluronic acid (HA) nanoparticles (NPs) utilizing layer by layer technique to achieve enhanced and precise delivery as well as target specificity. The NPs were evaluated for in vitro release, particle size, zeta potential, and cytotoxicity on A549 cells. The optimized NPs exhibited a particle size of 194 ± 2.90 nm, - 27.87 ± 3.21 mV zeta potential, and 80.70 ± 4.29% release, respectively, over a period of 48 h. Flow cytometric analysis revealed superior performance of HA-PCL-CAP in terms of suppressed cell viability in A549 cell lines when compared with CAP and PCL-CAP. Further, HA-anchored NPs were evaluated in vivo for their therapeutic efficacy in urethane-induced lung carcinoma in rat model. The superlative therapeutic potential of HA-PCL-CAP was advocated from the results of reactive oxygen species and mitochondrial membrane-mediated apoptosis. HA-PCL-CAP-administered groups presented greater therapeutic efficacy as revealed through reduced tumor volume and improved animal survival rate. A greater drug accumulation in tumor tissue as revealed from biodistribution studies evidences targeting potential of HA-PCL-CAP in urethane-induced lung carcinoma. Graphical abstract ᅟ.

Non-Pungent n-3 Polyunsaturated Fatty Acid (PUFA)-Derived Capsaicin Analogues as Potential Functional Ingredients with Antioxidant and Carbohydrate-Hydrolysing Enzyme Inhibitory Activities

N-Eicosapentaenoyl vanillylamine (EPVA) and N-docosahexaenoyl vanillylamine (DHVA), derived from n-3 polyunsaturated eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), respectively, were studied for their potential antioxidant and carbohydrate-hydrolysing enzyme inhibitory activities together with capsaicin and the corresponding n-3 polyunsaturated fatty acids (PUFAs). The antioxidant potential was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS) assay, β-carotene bleaching test, and ferric reducing ability power (FRAP). In the ABTS assay the following trend of potency could be observed EPVA > DHVA ≥ capsaicin. In addition, except for the FRAP test, all samples showed a greater activity than the positive controls used as reference compounds in the antioxidant assays. Both EPVA and DHVA showed half maximal inhibitory concentration (IC₅₀) values much lower than acarbose, which was used as the reference drug in the carbohydrate-hydrolysing enzyme inhibitory activity assays. It is interesting to note that structural changes in capsaicin derivatives had higher impacts on α-glucosidase than on α-amylase inhibition. Taken together, our data suggest that both EPVA and DHVA, which are not limited in compliance-related considerations with respect to capsaicin, due to absence of pungency, could be proposed as functional ingredients for the development of products for the management of type II diabetes and border-line hyperglycaemic patients.

Capsaicin in Hot Chili Peppers: In Vitro Evaluation of Its Antiradical, Antiproliferative and Apoptotic Activities

Capsaicin is a spicy capsaicinoid, produced as secondary metabolite by Capsicum fruits. This alkaloid has been used for years in folk medicine for its analgesic and antinflammatory properties although most data is referred to the raw fruit. In this study, the antiradical activity of the pure capsaicin has been studied using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assays as well as its antiproliferative activity, using MTT assay, against two human tumour cell lines, the colorectal Caco-2 and the oesophageal OE19 cells. Furthermore, the antiproliferative activity observed on tumoral cells was compared with that of the human normal-like fibroblast cell line TelCOFS02MA. In addition, the apoptotic activity was evaluated using TUNEL assay. A higher radical scavenging activity was observed against ABTS radical cation than DPPH. Capsaicin showed also a higher cytotoxicity against cancer cells than normal-like cells with Selectivity index values greater than 2 at 72 h. Capsaicin induced apoptosis especially in OE19 cell line.

Capsaicin-like analogue induced selective apoptosis in A2058 melanoma cells: Design, synthesis and molecular modeling

The use of molecules inspired by natural scaffolds has proven to be a very promising and efficient method of drug discovery. In this work, capsaicin, a natural product from Capsicum peppers with antitumor properties, was used as a prototype to obtain urea and thiourea analogues. Among the most promising compounds, the thiourea compound 6g exhibited significant cytotoxic activity against human melanoma A2058 cells that was twice as high as that of capsaicin. Compound 6g induced significant and dose-dependent G₀/G₁ cell cycle arrest in A2058 cells triggering cell death by apoptosis. Our results suggest that 6g modulates the RAF/MEK/ERK pathway, inducing important morphological changes, such as formation of apoptotic bodies and increased levels of cleaved caspase-3. Compared to capsaicin, 6g had no significant TRPV1/6 agonist effect or irritant effects on mice. Molecular modeling studies corroborate the biological findings and suggest that 6g, besides being a more reactive molecule towards its target, may also present a better pharmacokinetic profile than capsaicin. Inverse virtual screening strategy found MEK1 as a possible biological target for 6g. Consistent with these findings, our observations suggested that 6g could be developed as a potential anticancer agent.

Psychiatric Disorders and Oxidative Injury: Antioxidant Effects of Zolpidem Therapy disclosed In Silico

Zolpidem (N,N-Dimethyl-2-[6-methyl-2-(4-methylphenyl)imidazo[1,2-a]pyridin-3-yl]acetamide) is a well-known drug for the treatment of sleeping disorders. Recent literature reports on positive effects of zolpidem therapy on improving renal damage after cisplatin and on reducing akinesia without sleep induction. This has been ascribed to the antioxidant and neuroprotective capacity of this molecule, and tentatively explained according to a generic structural similarity between zolpidem and melatonin. In this work, we investigate in silico the antioxidant potential of zolpidem as scavenger of five ROSs, acting via hydrogen atom transfer (HAT) mechanism; computational methodologies based on density functional theory are employed. For completeness, the analysis is extended to six metabolites. Thermodynamic and kinetic results disclose that indeed zolpidem is an efficient radical scavenger, similarly to melatonin and Trolox, supporting the biomedical evidence that the antioxidant potential of zolpidem therapy may have a beneficial effect against oxidative injury, which is emerging as an important etiopathogenesis in numerous severe diseases, including psychiatric disorders.

A synergistic approach for management of lung carcinoma through folic acid functionalized co-therapy of capsaicin and gefitinib nanoparticles: Enhanced apoptosis and metalloproteinase-9 down-regulation

BACKGROUND

Lung cancer is one of the most lethal cancers and lacks effective treatment strategy. Therapeutic efficacy can be improved through active targeting approach utilizing surface engineered nanoparticles (NPs) for cancer therapy.

PURPOSE

The present study envisioned development of Folic acid (FA) functionalized NPs for co-administration of gefitinib (Gnb) and capsaicin (Cap) respectively to enhance the therapeutic outcome by disabling the barriers related to tumors extracellular matrix.

RESEARCH METHODS AND PROCEDURE

The FA conjugated Gnb/Cap polymeric (PLGA-PEG) NPs were prepared using oil in water emulsion technique and methodically developed using Quality by Design (QbD) concept employing central composite design. The developed formulations were subjected to various in vitro (A549 cell lines) and in vivo evaluations in urethane-induced lung cancer.

RESULTS

The modified NPs displayed particle sizes of 217.0 ± 3.2 nm and 213.0 ± 5.2 nm and drug release of 85.65 ± 3.21% and 81.43 ± 4.32% for Gnb and Cap respectively. Higher cellular uptake and lower cell viability in A549 cell line was displayed by functionalized NPs compared to free drug. Co administration of Gnb and Cap NPs displayed significant targeting potential, reduction in tumor volume while restoring the biochemical parameters viz., SOD, catalase, TBARS and protein carbonyl, towards normal levels when compared with toxic group. Significant down regulation was observed for anti-apoptotic proteins (MMP-9) and up regulation of pro-apoptotic proteins (caspase-3, caspase-9 and MMP-9) with co-therapy of Gnb and Cap NPs, when compared with individual therapy through Gnb/Cap.

CONCLUSION

Potentiation of the action of Gnb when co administered with Cap NPs can be a promising breakthrough for developing safe, effective and targeted delivery for lung carcinoma therapy.

Experimental and theoretical investigation of cyclometalated phenylpyridine iridium(iii) complex based on flavonol and ibuprofen ligands as potent antioxidant

An Ir(iii) complex was synthesized using mixed ligands of biological importance, namely ibuprofen, flavonol and 2-phenylpyridine. The compound was characterized by ¹H-NMR, ¹³C-NMR and TOF-MS spectroscopies and elemental analysis. Structures of the complex and its ligands were also calculated by density functional theory using B3LYP/Lanl2dz//6-31G(d) level of theory. Analyses of electrostatic potential, natural population, and frontier orbitals of the molecules as well as the calculation of intrinsic thermochemical properties such as bond dissociation enthalpy, ionization potential, electron affinity and proton affinity in the gas phase and in solvents (water and pentylethanoate) give the first indication that the complex is a potential antioxidant. The latter even shows better antioxidant capacity than the parent ligands. The antioxidant properties of the complex and its ligands were experimentally evaluated by studying the free radical scavenging activity towards HO˙, NO˙, DPPH˙ and ABTS˙⁺ radicals. Further computational work on the antioxidant processes such as the single electron transfer, the proton loss, the formal hydrogen transfer (FHT) and the radical adduct formation reactions was conducted. Results show that the FHT reaction is the mechanism responsible for the radical scavenging activity of the complex towards HO˙, HOO˙, NO˙ and DPPH˙ radicals while ABTS˙⁺ seems to be scavenged by an electron-donating mechanism. The FHT was further determined as a hydrogen-atom transfer but not a proton-couple electron transfer mechanism.

A cyclometalated phenylpyridine iridium(iii) complex based on flavonol and ibuprofen was designed and its antioxidant activity was evaluated via experimental and theoretical studies.

The Investigation of the Antitumor Agent Toxicity and Capsaicin Effect on the Electron Transport Chain Enzymes, Catalase Activities and Lipid Peroxidation Levels in Lung, Heart and Brain Tissues of Rats

Cisplatin is one of the most active cytotoxic agents in cancer treatment. To clarify the interaction with mitochondria, we hypothesize that the activities of mitochondrial electron transport chain (ETC) enzymes succinate dehydrogenase (SDH) and cytochrome c oxidase (COX), nucleotide levels, as well as levels of catalase (CAT) enzyme and membrane lipid peroxidation (LPO) can be affected by cisplatin. There was a significant decrease of both SDH and COX activities in the lung, heart, and brain tissues at the 1st day after cisplatin exposure, and the observed decreased levels of adenosine triphosphate (ATP) and adenosine diphosphate (ADP) in comparison with the control could be because of cisplatin-induced mitochondrial dysfunction. The investigations suggested that cisplatin inhibits SDH, COX, and ATP synthase. The higher LPO level in the studied tissues after 1 and 4 days post-exposure to cisplatin compared to control can be inferred to be a result of elevated electron leakage from the ETC, and reactive oxygen species (ROS) can lead to wide-ranging tissue damage such as membrane lipid damage. Consequently, it was observed that capsaicin may have a possible protective effect on ETC impairment caused by cisplatin. The activities of SDH and COX were higher in heart and brain exposed to cisplatin + capsaicin compared to cisplatin groups, while LPO levels were lower. The investigated results in the cisplatin + capsaicin groups suggested that the antioxidant capacity of capsaicin scavenges ROS and prevents membrane destruction.