Anticancer potential of allicin: A review.

Phytochemicals have attracted attention in the oncological field because they are biologically friendly and have relevant pharmacological activities. Thanks to the intense and unique spicy aroma, garlic is one of the most used plants for cooking. Its consumption is correlated to health beneficial effects towards several chronic diseases, such as cancer, mainly attributable to allicin, a bioactive sulfur compound stored in different plant parts in a precursor form. The objective of this review is to present and critically discuss the chemistry and biosynthesis of allicin, its pharmacokinetic profile, its anticancer mechanisms and molecular targets, and its selectivity towards tumor cells. The research carried out so far revealed that allicin suppresses the growth of different types of tumors. In particular, it targets many signaling pathways associated with cancer development. Future research directions are also outlined to further characterize this promising natural product.

Castanea sativa Mill. bark extract cardiovascular effects in a rat model of high-fat diet.

Ellagitannins may have a beneficial impact in cardiovascular diseases. The aim of the study was to evaluate the effect of high-fat diet (HFD) and the efficacy of Castanea sativa Mill. bark extract (ENC) on cardiac and vascular parameters. Rats were fed with regular diet, (RD, n = 15), HFD (n = 15), RD + ENC (20 mg/kg/day by gavage, n = 15), and HFD + ENC (same dose, n = 15) and the effects on body weight, biochemical serum parameters, and inflammatory cytokines determined. Cardiac functional parameters and aorta contractility were also assessed on isolated atria and aorta. Results showed that ENC reduced weight gain and serum lipids induced by HFD. In in vitro assays, HFD decreased the contraction force of left atrium, increased right atrium chronotropy, and decreased aorta K+ -induced contraction; ENC induced transient positive inotropic and negative chronotropic effects on isolated atria from RD and HFD rats and a spasmolytic effect on aorta. In ex vivo experiments, ENC reverted inotropic and chronotropic changes induced by HFD and enhanced Nifedipine effect more on aorta than on heart. In conclusion, ENC restores metabolic dysfunction and cardiac cholinergic muscarinic receptor function, and exerts spasmolytic effect on aorta in HFD rats, highlighting its potential as nutraceutical tool in obesity.

Co-carcinogenic effects of vitamin E in prostate.

A large number of basic researches and observational studies suggested the cancer preventive activity of vitamin E, but large-scale human intervention trials have yielded disappointing results and actually showed a higher incidence of prostate cancer although the mechanisms underlying the increased risk remain largely unknown. Here we show through in vitro and in vivo studies that vitamin E produces a marked inductive effect on carcinogen-bioactivating enzymes and a pro-oxidant status promoting both DNA damage and cell transformation frequency. First, we found that vitamin E in the human prostate epithelial RWPE-1 cell line has the remarkable ability to upregulate the expression of various phase-I activating cytochrome P450 (CYP) enzymes, including activators of polycyclic aromatic hydrocarbons (PAHs), giving rise to supraphysiological levels of reactive oxygen species. Furthermore, our rat model confirmed that vitamin E in the prostate has a powerful booster effect on CYP enzymes associated with the generation of oxidative stress, thereby favoring lipid-derived electrophile spread that covalently modifies proteins. We show that vitamin E not only causes DNA damage but also promotes cell transformation frequency induced by the PAH-prototype benzo[a]pyrene. Our findings might explain why dietary supplementation with vitamin E increases the prostate cancer risk among healthy men.

Liver and intestinal protective effects of Castanea sativa Mill. bark extract in high-fat diet rats.

The effects of Castanea sativa Mill. have been studied in high fat diet (HFD) overweight rats. Natural Extract of Chestnut bark (Castanea sativa Mill.) (ENC®), rich in ellagitannins, has been studied in 120 male Sprague-Dawley rats, divided in four groups. Two groups were controls: regular (RD) and HDF diet. Two groups received ENC® (20 mg/kg/day): RD + ENC® and HFD + ENC®. At baseline and at 7, 14 and 21 days, weight gain, serum lipids, plasma cytokines, liver histology, microsomial enzymes and oxidation, intestinal oxidative stress and contractility were studied. HFD increased body weight, increased pro-inflammatory cytokines, induced hepatocytes microvescicular steatosis, altered microsomial, increased liver and intestinal oxidative stress, deranged intestinal contractility. In HFD-fed rats, ENC® exerted antiadipose and antioxidative activities and normalized intestinal contractility, suggesting a potential approach to overweight management associated diseases.

Dietary effects of Raphanus sativus cv Sango on lipid and oxysterols accumulation in rat brain: A lipidomic study on a non-genetic obesity model.

The present study aimed to evaluate the impact of Raphanus sativus cv Sango sprout juice (SSJ) administration (75mg/kg b.w. SSJ/day) on the brain lipidomic profile (fatty acid, sterols, cholesterol oxidation) of rats (non-genetic model) subjected to a high-fat (34% crude fat) dietary regimen. The SSJ did not affect the lipid infiltration (7.7-9.3%) and the fatty acid composition of the rat brain, which was mainly composed by unsaturated fatty acids (∼58%); however, the high-fat diet regimen significantly halved linoleic acid (LA). The high-fat diet also decreased (21.13mg/g) the level of brain cholesterol with respect to the regular diet (4.5% crude fat) (23.83mg/g); however, when the diet was shifted from high-fat to a regular regimen with or without SSJ supplementation, the levels of cholesterol significantly (p <0.05) increased up to 30.46mg/g of brain. The main oxysterols were 24(S)-hydroxycholesterol (24(S)-HC) and ß-epoxycholesterol (ß-EC). The high-fat diet led to the highest cholesterol oxidation (63.1µg/g), increasing 27-hydroxycholesterol (27-HC) infiltration (0.24µg/g rat brain) through the blood-brain barrier (BBB) compared to the regular diet (0.13µg/g rat brain). On the other hand, when the diet was switched from high-fat to a regular regimen with SSJ supplementation, a significant reduction of 27-HC in the rat brain was found. Although 24-HC did not significantly change (p=0.054), an increasing trend was observed when high-fat diet was supplied. The principal component analysis (PCA) revealed that SSJ was more active in counteracting cholesterol oxidation when supplied with the high-fat diet, due to inverse correlation with 24(S)-HC and 27-HC; however, further studies are needed to better understand which is the relationship between LA and cholesterol homeostasis in rat brain.

Comparison between in toto peach (Prunus persica L. Batsch) supplementation and its polyphenolic extract on rat liver xenobiotic metabolizing enzymes.

Over the past years, there has been a growing interest in the natural constituents of foods as a potential means of cancer control. To date, epidemiology studies seem to indicate an inverse association between regular consumption of fruit and vegetables and cancer risk. Here, the potential chemopreventive activity of the polyphenolic extract (PPE) of peach (Prunus persica L. Batsch) and of the freeze-dried fruit in toto (LFT), focusing on the modulation of xenobiotic metabolizing enzymes (XMEs) in vivo, was investigated. Rats were daily supplemented with LFT at 250 and 500 mg/kg b.w. or with the corresponding amount of PPE (2.5 and 5 mL/kg b.w., respectively) for either 7 or 14 days. While PPE treatment resulted in a widespread phase-I inactivation, a complex modulation pattern with drastic decreases (7α-testosterone hydroxylase, pentoxyresorufin O-dealkylase (PROD)), coupled with marked up-regulations of ethoxyresorufin O-deethylase (EROD) and methoxyresorufin O-demethylase (MROD) after LFT administration, was seen. A notable down-regulation (over 50%) following LFT or PPE treatment for the phase-II enzymes was also recorded. The observed remarkable changes in XMEs, if reproduced in humans, might have public health implications. These data suggest caution in promoting peach fruit (mono-diet) consumption or its polyphenolic extract in the field of chemoprevention.

Harmful effects behind the daily supplementation of a fixed vegetarian blend in the rat model.

Fruit and vegetables (FV) have long been considered a panacea against major chronic diseases, including cancer. However, there is no convincing epidemiological, clinical or experimental evidence supporting FV chemopreventive ability. A daily mono-supplementation of lyophilized onion, tomato, peach, black grape or lettuce was compared with the daily combined administration of the same FV (5 a day-like diet). Ten days post-treatment, the phase-I/II xenobiotic metabolizing and antioxidant enzyme activities, protein and mRNA levels were investigated. As a marker of oxidative stress, the level of hydroperoxides was measured in rat serum samples. Here we show that a blend of FV orally administered to rats not only potentially manipulates metabolism but also disrupts systemic oxidative homeostasis. A daily combination of the five servings remarkably down-regulates the catalytic activity, protein and mRNA levels of a cohort of hepatic metabolizing enzymes, suggesting a possible depressed clearance upon exposure to ubiquitous carcinogens. Strikingly, we observed an impairment of antioxidant enzymes with a boost in systemic hydroperoxide levels. Our study identifies new potential factors of cancer risk connected with the persistent consumption of fixed servings of FV, suggesting that dietary guidance should rely on a "daily diversification" of FV.

Effects of N-acetylcysteine on human ovarian tissue preservation undergoing cryopreservation procedure.

The aim of the study was to evaluate the effects of the antioxidant N-acetylcysteine (NAC), added in freezing/thawing solutions, on reactive oxygen species (RRS) levels and on ovarian tissue preservation after cryopreservation. Ovarian samples from 10 subjects suffering from cancer diseases were cryopreserved using the slow freezing/rapid thawing standard protocol without or with NAC supplementation. RRS levels produced during cryopreservation were monitored by electron paramagnetic resonance (EPR) spectroscopy. The preservation of fresh ovarian tissue (t0), thawed tissue (t1 and t1 NAC) and thawed tissue maintained at 4°C for 2 hrs (t2 and t2 NAC) was analysed by light microscopy, transmission electron microscopy, Ki67 immunohistochemical and TUNEL analysis. It was possible to design a maximum peak for RRS production at t1, which slightly decreased at t2. NAC reduced the extent of RRS levels in cryopreserved ovarian tissues if compared with non-supplemented ones, although not restoring RRS production to baseline values. Comparative analysis between the two cryopreservation protocols showed that a better preservation of morphological characteristics, proliferation index and DNA integrity of ovarian tissue was obtained using NAC and no differences between t1NAC and t2NAC were observed. The employment of NAC during cryopreservation procedure could be an useful strategy for preserving the function of endogenous cellular systems. Nevertheless, further studies on the viability of thawed ovarian tissue are needed to support the feasibility of this approach in clinical settings.