Antiviral drugs as well as natural remedies have been used to reduce symptoms and the rate of recurrences of herpes simplex virus type 1 (HSV-1) infection, a common disease. To evaluate anti-HSV-1 activity of a pine cone lignin and ascorbic acid treatment, a clinical pilot study was carried out. Forty-eight healthy patients of both genders between 4 and 61 years old (mean: 31+/-16 years), with active lesions of HSV-1, took part in the study. According to the HSV-1 stage at the presentation, the patients were classified into the prodromic (16 patients), erythema (11 patients), papule edema (1 patient), vesicle/pustule (13 patients) and ulcer stages (7 patients). One mg of lignin-ascorbic acid tablet or solution was orally administered three times daily for a month. Clinical evaluations were made daily the first week and at least three times a week during the second week after the onset and every six months during the subsequent year to identify recurrence episodes. The patients who began the lignin-ascorbic acid treatment within the first 48 hours of symptom onset did not develop HSV-1 characteristic lesions, whereas those patients who began the treatment later experienced a shorter duration of cold sore lesions and a decrease in the symptoms compared with previous episodes. The majority of the patients reported the reduction in the severity of symptoms and the reduction in the recurrence episodes after the lignin-ascorbic acid treatment compared with previous episodes, suggesting its possible applicability for the prevention and treatment of HSV-1 infection.

OBJECTIVES:Chemotherapy is one of the major treatments of cancer. However, the emergence of resistance to chemotherapeutic agents is still a major obstacle in the successful management of resistant tumors. Therefore, development of new mechanisms to overcome drug resistance is essential and may be further developed into effective therapies that can flip the switch from drug resistance to susceptibility. The aim of this study was to evaluate a combination consisting of a ketogenic diet and melatonin to determine whether it would inhibit cisplatin- and vincristine-resistant breast cancer.

METHODS:In the in vitro part of the study, drug-resistant cell lines were treated with melatonin and real-time polymerase chain reaction was used to measure levels of gene expression involved in apoptosis and resistance. On the protein level, the activity of caspase-3 and the level of vascular endothelin growth factor protein were determined. In the in vivo part, tumor-bearing mice received one of the following treatments: ketogenic diet, melatonin, combination of melatonin and ketogenic diet, vehicle, or chemotherapy.

RESULTS:Successful inhibition of resistant cell lines was achieved by melatonin. This inhibition was mediated by induction of apoptosis, inhibition of angiogenesis, and downregulation of resistance genes. A synergistic anticancer effect was observed between melatonin and the ketogenic diet against resistant breast tumors inoculated in mice with a cure rate of 70%.

CONCLUSIONS:The combination of melatonin and a ketogenic diet represents a promising option to overcome drug resistance in cancer chemotherapy. However, further testing on the protein level using flow cytometry is important to better understand the mechanisms of action.

The intake of phenolic acids and related polyphenolic compounds has been inversely associated with the risk of heart disease, but limited information is available about their bioavailability or mechanisms of action. Polyphenolics, principally avenanthramides, and simple phenolic acids in oat bran phenol-rich powder were dissolved in HCl:H(2)O:methanol (1:19:80) and characterized by HPLC with electrochemical detection. The bioavailability of these oat phenolics was examined in BioF1B hamsters. Hamsters were gavaged with saline containing 0.25 g oat bran phenol-rich powder (40 micromol phenolics), and blood was collected between 20 and 120 min. Peak plasma concentrations of avenanthramides A and B, p-coumaric, p-hydroxybenzoic, vanillic, ferulic, sinapic, and syringic acids appeared at 40 min. Although absorbed oat phenolics did not enhance ex vivo resistance of LDL to Cu(2+)-induced oxidation, in vitro addition of ascorbic acid synergistically extended the lag time of the 60-min sample from 137 to 216 min (P

Coenzyme Q(10) (CoQ(10)) and creatine are promising agents for neuroprotection in neurodegenerative diseases via their effects on improving mitochondrial function and cellular bioenergetics and their properties as antioxidants. We examined whether a combination of CoQ(10) with creatine can exert additive neuroprotective effects in a MPTP mouse model of Parkinson's disease, a 3-NP rat model of Huntington's disease (HD) and the R6/2 transgenic mouse model of HD. The combination of the two agents produced additive neuroprotective effects against dopamine depletion in the striatum and loss of tyrosine hydroxylase neurons in the substantia nigra pars compacta (SNpc) following chronic subcutaneous administration of MPTP. The combination treatment resulted in significant reduction in lipid peroxidation and pathologic alpha-synuclein accumulation in the SNpc neurons of the MPTP-treated mice. We also observed additive neuroprotective effects in reducing striatal lesion volumes produced by chronic subcutaneous administration of 3-NP to rats. The combination treatment showed significant effects on blocking 3-NP-induced impairment of glutathione homeostasis and reducing lipid peroxidation and DNA oxidative damage in the striatum. Lastly, the combination of CoQ(10) and creatine produced additive neuroprotective effects on improving motor performance and extending survival in the transgenic R6/2 HD mice. These findings suggest that combination therapy using CoQ(10) and creatine may be useful in the treatment of neurodegenerative diseases such as Parkinson's disease and HD.

Although cisplatin is a potent anticancer drug, it instigates oxidative and pro-inflammatory reactions which poses significant and distressing clinical symptoms in patients including nausea and vomiting which is related to damage of the gastric mucosa. This study investigated the effects of vitamin C and/or L-carnitine on cisplatin-induced gastric mucosa damage in rat. The rats were allocated into groups (n=5): a control group received distilled water and treatment groups received cisplatin (CIP) alone, cisplatin followed by vitamin C, L-carnitine or their combination. Cisplatin treatment caused disruption of the gastric mucosa histoarchitecture and alter the mucus barrier function in the gastric mucosa. Moreover, stomach tissue from the CIP treated group had increased levels of oxidative stress markers, malondialdehyde and H2O2 levels, and decreased activity of the antioxidant enzymes superoxide dismutase, glutathione peroxidase, catalase, glutathione S-transferase and non-antioxidant enzyme, reduced glutathione level. These deleterious events were accompanied by upregulated levels of the pro-inflammatory cytokines, tumor necrosis factor-alpha, interleukin-1beta, and inflammatory infiltration markers, myeloperoxidase and inducible nitric oxide synthase (iNOS). However, administration of both vitamin C and L-carnitine, and not the either of the two showed additive effect in attenuating these toxic effects which were confirm histologically. In conclusion, the combined administration of vitamin C and L-carnitine, but not the single therapy, could prevent the adverse effects of cisplatin on gastric tissues.

This study was aimed to evaluate the combined effect of curcumin with vitamin C supplementation on hyperglycemic and dyslipidemia conditions and endothelial cell dysfunction induced in diabetic rats. Wistar Furth rats were used and divided into four groups: control (single injection of 0.9% sterile saline), STZ (streptozotocin, Sigma, 55 mg/kg.BW, i.v.), STZ-vitC (1 g/l ascorbic acid mixed in drinking water), STZ-cur (daily oral treatment of 300 mg/kg.BW curcumin; Cayman Chemical Co., USA), and STZ-cur+vitC (1 g/l ascorbic acid mixed in drinking water and oral treatment of 300 mg/kg.BW curcumin). On 8th week after STZ-injection, the microcirculation in the iris tissue was observed using intravital fluorescence videomicroscopy, and also leukocyte adhesion in the venule was examined for each group. Blood glucose (BG), lipid profiles, glycosylated hemoglobin (HbA1c) were measured in blood samples collected at the end of each experiment. The contents of liver malondialdehyde (MDA) were also quantified for each group. Feeding curcumin (STZ-cur) could decrease BG, HbA1c, dyslipidemia, and MDA significantly, compared to STZ. In cases of feedings curcumin with vitamin C, these results were more effective in all aspects, including leukocyte adhesion. In conclusion, curcumin might increase the effect of vitamin C in protecting the function of endothelial cells through its anti-oxidant with hypoglycemic and hypolipidemic actions.

:Urinary tract infections (UTIs) are common in women and many patients with recurrent UTIs do not eradicate the condition albeit being treated with multiple courses of antibiotics. The use of nutritional supplements might reduce the risk of recurrent UTIs. However, the role of supplements taken as single agents appears to be limited. We hypothesized that a combination of cranberries, Lactobacillus rhamnosus, and vitamin C might produce a clinical benefit due to their additive or synergistic effects. We prospectively enrolled 42 consecutive women with recurrent UTIs treated with 120mg cranberries (minimum proanthocyanidin content: 32mg), 1 billion heat-killed L. rhamnosus SGL06, and 750mg vitamin C thrice daily for 20 consecutive d. Patients were advised to stop taking these supplements for 10 d and then to repeat the whole cycle three times. Patients were contacted three mo and six mo following the end of the administration of these supplements and evaluated with a semistructured interview and urinalysis. Responders were defined as the absence of symptoms and negative urinalysis or urine culture. Follow-up data were available for 36 patients. Overall, 26 (72.2%) and 22 patients (61.1%) were responders at the 3-mo and 6-month follow-up. No major side effects were recorded. The administration of cranberries, L. rhamnosus, and vitamin C might represent a safe and effective option in women with recurrent UTIs.

PATIENT SUMMARY:We evaluated the effectiveness of cranberries, Lactobacillus rhamnosus, and vitamin C thrice daily for 20 consecutive d monthly for 3 mo for the management of recurrent urinary tract infections in women. Our results show that this approach might represent a safe and effective option.

BACKGROUND:The purpose of this study is to determine the effect of L-ascorbic acid and alpha-tocopherol as well as combination of these vitamins with or without exposure to physical exercise on intensity of lipid peroxidation, activity of xanthine oxidase, activity of total antioxidative system, concentration of glutathione, and activity of catalase in the serum of guinea pigs.

MATERIALS AND METHODS:The experimental measurements of intensity of lipid peroxidation, activity of xanthine oxidase, activity of total antioxidative system, concentration of glutathione, and activity of catalase were done in the serum of guinea pigs. The animals were exposed to the test load to achieve exhaustion and the test was terminated when the animal for the third time to sink into the water.

RESULTS:The results of this study demonstrated that endurance exercise of guinea pigs induced oxidative stress response in terms of increased lipid peroxidation and activity of xanthine oxidase in the serum of experimental animals. Our study investigated the antioxidant activity of L-ascorbic acid and alpha-tocopherol also measuring three protective markers in the serum: total antioxidant activity, content of glutathione and activity of catalase. The results obtained show that the vitamins influence the concentrations of above mentioned biochemical parameters, which points out their protective effect of swimming-induced oxidative stress.

CONCLUSION:Single or combined administration of L-ascorbic acid and alpha-tocopherol caused significant inhibition of these markers indicating the important antioxidant activity of the vitamins. Results lead to conclude that the combined treatments with vitamins with or without exposure to physical exercise showed the clear synergistic effect..

BACKGROUND:The purpose of this study is to determine the effect of L-ascorbic acid and alpha-tocopherol as well as combination of these vitamins with or without exposure to physical exercise on intensity of lipid peroxidation, activity of xanthine oxidase, activity of total antioxidative system, concentration of glutathione, and activity of catalase in the serum of guinea pigs.

MATERIALS AND METHODS:The experimental measurements of intensity of lipid peroxidation, activity of xanthine oxidase, activity of total antioxidative system, concentration of glutathione, and activity of catalase were done in the serum of guinea pigs. The animals were exposed to the test load to achieve exhaustion and the test was terminated when the animal for the third time to sink into the water.

RESULTS:The results of this study demonstrated that endurance exercise of guinea pigs induced oxidative stress response in terms of increased lipid peroxidation and activity of xanthine oxidase in the serum of experimental animals. Our study investigated the antioxidant activity of L-ascorbic acid and alpha-tocopherol also measuring three protective markers in the serum: total antioxidant activity, content of glutathione and activity of catalase. The results obtained show that the vitamins influence the concentrations of above mentioned biochemical parameters, which points out their protective effect of swimming-induced oxidative stress.

CONCLUSION:Single or combined administration of L-ascorbic acid and alpha-tocopherol caused significant inhibition of these markers indicating the important antioxidant activity of the vitamins. Results lead to conclude that the combined treatments with vitamins with or without exposure to physical exercise showed the clear synergistic effect..

PURPOSE:The aim of the present study was to investigate the effects of the consumption of two cloudy apple juices with different polyphenol and vitamin C contents on antioxidant status, cardiometabolic and inflammation markers in healthy young adults.

METHODS:Twenty subjects, aged 21-29 years, completed a randomized crossover study. At each 4-week intervention period, the volunteers randomly consumed two glasses (2× 250 mL/day) of either a vitamin C-rich apple juice (VCR) (60 mg/L vitamin C and 510 mg catechin equivalent/L) or a polyphenol-rich (PR) juice (22 mg/L vitamin C and 993 mg catechin equivalent/L). Blood and urine samples were collected throughout the study, and markers of antioxidant status, glucose metabolism, lipid profile and inflammation were measured.

RESULTS:The comparison of the post-intervention minus pre-intervention change revealed differential results in HOMA index, total cholesterol, ICAM-1 and VCAM-1 (P<0.05) across juices. During the VCR period, plasma antioxidant activity (FRAP) increased (P = 0.031), while ICAM-1 and total cholesterol showed a trend to decrease (P = 0.060 and P = 0.094, respectively). During the PR period, plasma insulin and HOMA increased, and total glutathione decreased (P<0.05).

CONCLUSIONS:A joint consumption of apple juice natural antioxidants such as vitamin C and polyphenols might provide mild favorable effects on cardiometabolic markers, as compared to apple polyphenols alone.

Plant foods are endowed with micronutrients but an understanding of bioavailability is essential in countries primarily dependent on plant based foods. Bioavailability depends majorly on food synergies. This review examines the nature of certain food synergies and methods to screen and establish it as a strategy to control micronutrient deficiency in the populations. Strong evidence on the synergistic effect of inclusion of vitamin C rich fruits and non-vegetarian foods in enhancing the bioavailability of iron has been demonstrated. Fat is found to be synergistic for vitamin A absorption. Red wine and protein have been explored for zinc absorption and effect of fat has been studied for vitamin D. Methods for screening of bioavailability, and biomarkers to demonstrate the synergistic effects of foods are required. Translation of food synergy as a strategy requires adaptation to the context and popularization of intelligent food synergies.

Photoactivation of hypericin is known to generate singlet oxygen and superoxide anion radicals. Reactive oxygen species (ROS) produced by photodynamic therapy (PDT) has the capacity to induce oxidative damage and tumor destruction. We have previously shown that hypericin-PDT induces tumor shrinkage and regression in the human nasopharyngeal cancer (NPC)/HK1 murine tumor model. In this extended study, we show by electron microscopy that subcutaneously implanted HK1 NPC cells from Balb/c nude mice perished by cell necrosis with hypericin-PDT treatment. There was evidence of cytoplasmic swelling accompanied by loss of cell membrane integrity and autophagic vacuolization of cytoplasm but no nuclear changes. There was also no significant difference in the apoptotic index of control and PDT-treated tumors, when analyzed by in situ end labeling of DNA strand breakage to detect apoptosis. This further supports the observation that cell death in PDT-treated NPC/HK1 tumors was by necrosis. Lipid peroxidative stress analyzed by the malonaldehyde assay was significantly elevated in PDT-treated cells. However, PDT had no effect on the activity of superoxide dismutase, an intracellular antioxidant enzyme. The findings show that hypericin-PDT of nasopharyngeal tumors in vivo induces tumor necrosis with accompanying lipid peroxidation.

BACKGROUND:Since oxidative stress and inflammation are two linked factors in the pathogenesis of several human diseases. Thus identification of effective treatment is of great importance. Edible mushroom and microalgae are rich in the effective antioxidant phytochemicals. Hence, their beneficial effects on oxidative stress-associated inflammation are extremely required to be investigated.

METHODS:This study evaluated the functional constituents, antioxidant and anti-inflammatory activities of Malaysian Ganoderma lucidum aqueous extract (GLE) and Egyptian Chlorella vulgaris ethanolic extract (CVE). Also, the synergistic, addictive or antagonistic activities of the combination between the two extracts (GLE-CVE) were studied. Expression of inducible nitric oxide synthase, cyclooxygenase-2, and nuclear factor-kappa B, as well as levels of nitric oxide, tumor necrosis factor (TNF)-α, lipid peroxidation, reduced glutathione and antioxidant enzymes were determined using in vitro model of lipopolysaccharide-stimulated white blood cells.

Khz (fusion of Ganoderma lucidum and Polyporus umbellatus), isolated from the mycelia of G. lucidum and P. umbellatus, exerts anti‑proliferative effects against malignant cells; however, its activity against human breast cancer cells remains to be elucidated. In the present study, cell proliferation was assessed using a 3-(4,5‑dimethylthiazol‑2‑yl)-2,5‑diphenyltetrazolium bromide assay, and poptosis was examined using annexin V‑propidium iodide staining and flow cytometry. The activation of caspases 7, 8 and 9 were detected in the Khz‑treated cells using western blotting. The results demonstrated that Khz increased the intracellular calcium concentration and induced the production of reactive oxygen species in MCF‑7 breast cancer cells, as determined using flow cytometry. The results also demonstrated that Khz inhibited cell proliferation and induced apoptosis in the MCF‑7 cells. In addition, the mechanism by which Khz induces apoptosis in cancer cells was investigated. Khz induced apoptosis preferentially in transformed cells, with a minimal effect on non‑transformed cells, suggesting its potential as an anticancer therapeutic agent. Oxidative stress is associated with apoptotic and non‑apoptotic cell death, although pro‑oxidative conditions are not a pre‑requisite for apoptosis. Assessment of the activation status of caspases 7, 8 and 9 revealed that the levels of cleaved caspases were significantly increased in the cells treated with Khz. It is widely accepted that calcium signaling is important in apoptosis, and the present study observed an increase in [Ca2+]i in response to Khz treatment. The anti‑proliferative and pro‑apoptotic effects of Khz suggest that this extract may be developed as a potential anticancer agent.

OBJECTIVE:Critical macromolecules such as DNA maybe damaged by free radicals that are generated from the interaction of ionizing radiation with biological systems. Melatonin and vitamin C have been shown to be direct free radical scavengers. The aim of this study was to investigate the in vivo/in vitro radioprotective effects of melatonin and vitamin C separately and combined against genotoxicity induced by 6 MV x-ray irradiation in human cultured blood lymphocytes.

MATERIALS AND METHODS:In this experimental study, fifteen volunteers were divided into three groups of melatonin, vitamin C and melatonin plus vitamin C treatment. Peripheral blood samples were collected from each group before, and 1, 2 and 3 hours after melatonin and vitamin C administration (separately and combined). The blood samples were then irradiated with 200 cGy of 6 MV x-ray. In order to characterize chromosomal aberrations, the lymphocyte samples were cultured with mitogenic stimulus on cytokinesisblocked binucleated cells.

RESULTS:The samples collected 1hour after melatonin and vitamin C (separately and combined) ingestion exhibited a significant decrease in the incidence of micronuclei compared with their control group (P<0.05). The maximum synergic protection and reduction in frequency of micronuclei (57%) was observed 1 hour after vitamin C and melatonin administration combined.

CONCLUSION:We conclude that simultaneous administration of melatonin and vitamin C as radioprotector substances before irradiation may reduce genotoxicity caused by x-ray irradiation.

Oxidative stress causes the generation of reactive oxygen species (ROS) that lead to nephrotoxicity. An aminoglycoside, gentamicin, has pronounced nephrotoxic effect in humans and animals and this study was planned to observe the nephro-protective effect of antioxidants, vitamin C and Nigella sativa oil. Serum creatinine, blood urea nitrogen, and antioxidant activity were measured as indicators of nephrotoxicity for all the groups of rabbits. Results showed that vitamin C and Nigella sativa oil both had nephro-protective effect as they lowered the values of nephrotoxicity indicators (serum creatinine, blood urea nitrogen, and antioxidant activity) as compared to gentamicin control group values. When these two antioxidants were given as combination, they proved to have synergistic nephro-protective effect.

Ascorbic acid (A) has been demonstrated to exhibit anti-cancer activity in association with chemotherapeutic agents. Potassium (K) is a regulator of cellular proliferation. In the present study, the biological effects of A and K bicarbonate, alone or in combination (A+K), on breast cancer cell lines were evaluated. The survival of cancer cells was determined by sulforhodamine B cell proliferation assay, while analysis of the cell cycle distribution was conducted via fluorescence-activated cell sorting. In addition, the expression of signaling proteins was analyzed upon treatment. The results indicated that there was a heterogeneous response of the different cell lines to A and K, and the best effects were achieved by A+K and A treatment. The interaction between A+K indicated an additive or synergistic effect. In addition, A+K increased the percentage of cells in the sub-G1 phase of the cell cycle, and was the most effective treatment in activating the degradation of poly(adenosine diphosphate-ribose) polymerase-1. In the breast cancer cell line MCF-7, A+K induced the appearance of the 18 kDa isoform of B-cell lymphoma-2-associated X protein (Bax), which is a more potent inducer of apoptosis than the full-length Bax-p21. The effects of A and K on the phosphorylation of extracellular signal-regulated kinase (ERK)1 and ERK2 were heterogeneous. In addition, treatment with K, A and A+K inhibited the expression of nuclear factor-κB. Overall, the results of the present study indicated that K potentiated the anti-tumoral effects of A in breast cancer cells in vitro.

PURPOSE:To explore the antitumor effect of prescription consisting of Vitamin C (Vc) and Baicalin (PVB).

METHODS:To explore the antitumor effect of PVB, using U14 cervical tumor-bearing mice model was used and the drugs were administrated through the gavages. Spectrophotometry was used to determine the content of superoxide dismutase (SOD), malondialdehyde (MDA) and cytokines IL-2, Il-4 and IFN-γ.

RESULTS:PVB had a better antitumor effect than baicalin and Vc used alone with an inhibition rate of 58.18% (p<0.05); PVB significantly improved the spleen index (p<0.01), and significantly reduced MDA content (p<0.01) but increased SOD activity in liver tissue and serum (p<0.01).

CONCLUSIONS:PVB shows better antitumor effect than Vc and baicalin used alone, and it can significantly enhance the immunity and antioxidant capacity of the mice.

BACKGROUND AND OBJECTIVES:The aim of the present study was to determine if the combination therapy of quercetin along with vitamins (C and E) has any advantage over the cadmium (Cd) induced oxidative stress and renal injury in rats. They were analysed serum and urinary markers of renal damage (urea, uric acid, creatinine and creatinine clearance), renal oxidative stress indices (thio barbituric acid reactive substances: TBARS, lipid hydroperoxides (LOOH) and protein carbonyls (PC), renal non-enzymatic [reduced glutathione (GSH), total sulphydryl groups (TSH)], vitamin-C and vitamin-E, enzymatic [superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), glutathione-s-transferase, GST)], glutathione metabolizing enzymes [glutathione reductase (GR) and glucose-6-phosphate dehydrogenase, (G6PD)] and histological changes in kidney.

RESULTS:Cd intoxication significantly (P>0.05) increased the levels of serum nephritic markers (urea, uric acid, creatinine) and significantly (P>0.05) reduced the urea, uric acid and creatinine in urine and serum creatinine clearance. It also significantly (P>0.05) increased renal oxidative stress markers and significantly (P>0.05) decreased renal non-enzymatic and enzymatic antioxidants status and severely increased the histo-pathological changes when compared to normal control rats. Cd intoxicated rats pre-treated with quercetin (QE) alone and QE along with vitamin-C (VC) and vitamin-E (VE) significantly ameliorated Cd induced anomalies in renal biochemical and histological indices.

CONCLUSION:The ameliorative effect against Cd intoxication was much pronounced in rats treated with QE along with vitamins C and E.

Alpha-tochopheryl succinate (αTOS), vitamin K3 (VK3) and vitamin C (ascorbic acid, AA) were previously shown to synergistically promote different death pathways in carcinoma cells, depending on their concentrations and combinations. Similar effects were observed herein in melanoma cells, although αTOS behaved as an antagonist. Interestingly, suboptimal cell death-inducing concentrations (1.5 μM αTOS/20 μM AA/0.2 μM VK3) effectively up-regulated activating Natural Killer (NK) cell ligands, including MICA (the stress-signaling ligand of the NKG2D receptor), and/or the ligands of at least one of the natural cytotoxicity receptors (NKp30, NKp44 and NKp46) in 5/6 melanoma cell lines. Only an isolated MICA down-regulation was seen. HLA class I, HLA class II, ULBP1, ULBP2, ULBP3, Nectin-2, and PVR displayed little, if any, change in expression. Ligand up-regulation resulted in improved lysis by polyclonal NK cells armed with the corresponding activating receptors. These results provide the first evidence for concerted induction of cell death by cell-autonomous and extrinsic (immune) mechanisms. Alarming the immune system much below the cell damage threshold may have evolved as a sensitive readout of neoplastictransformation and oxidative stress. Cocktails of vitamin analogues at slightly supra-physiological dosages may find application as mild complements of melanoma treatment, and in chemoprevention.