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Public feelings concerning radiation are still controversy. The main sources of trouble seems to be the failure nuclear power plant and danger of terroristic attack, which may cause temporally enhanced level of radiation leading to harmful health effects. Since radiation induced cellular damage is attributed primarily to harmful effect of free radicals, molecules with direct free radical scavenging properties are particularly promising as radiation modifiers/protectors, i.e. agents which present prior to or shortly after radiation exposure alter to response of tissues to radiation. Unfortunately, some of known radioprotectors are toxic at doses required for radioprotection. Resveratrol (RSV), an natural polyphenol is produced in several plants in response to injury, stress, bacteria or fungi infection, UV-irradiation and exposure to ozone. It is present in human diet i.e. in fruits and in wine. RSV is known for its antioxidant, anti-inflammatory, analgesic, antiviral, cardioprotective, neuroprotective and antiageing action and it has been shown to have chemopreventive effects with respect to several human disease such as cardiovascular disease, osteoporosis and gastric ulcers. Depending on the dose, RSV may act as antioxidant or as pro-oxidant. RSV improves sperm count and motility in rodents and prevent DNA damage caused by cryptopreservation of human sperm. Moreover, RSV acting with other agents, inhibits the toxic action of them. There are evidences that RSV is able to modulate the behavior of cells in response to radiation induced damage. Minimalization of radiation induced damage to somatic and germ cells by RSV might be useful in cancer therapy to prevent the damage to normal cells as well as in case of radiological accidents.
Resveratrol is the most extensively studied stilbene derivative. We previously showed that methylthiostilbenes were more effective inhibitors of CYP1A1 and 1B1 activity than resveratrol. In this study, we investigated whether resveratrol and its methylthio-substituted derivatives, i.e. 3-M-4′-MTS (S2), 3,5-DM-4′-MTS (S5) and 3,4,5-TM-4′-MTS (S7) could activate Nrf2 signaling in the mouse epidermis and in human keratinocytes. Western blot analysis showed translocation of Nrf2 from the cytosol to the nucleus in both models. All of the tested stilbenes increased GST activity, but resveratrol was the most effective inducer. Moreover, only resveratrol increased the protein level of GSTP in the mouse epidermis. GSTM was enhanced in HaCaT cells after the treatment with derivatives S2 and S5. The same effect was observed for GSTP in the case of compound S2. Resveratrol and its derivatives reduced the NQO2 protein level in HaCaT cells. Thus, it is possible that increased expression of GSTP or GSTM and GST activity was linked with NQO2 inhibition in these cells. The results of this study indicate that resveratrol and its methylthioderivatives activate Nrf2 not only in the mouse epidermis, but also in human keratinocytes. Upregulating GST isozymes might be particularly important for deactivating chemical carcinogens, such as PAH.
Resveratrol (RES), a component of red wine, possesses anti-inflammatory properties. The studies described in the present work were aimed at evaluating the potential for RES and related stilbene analogs (piceatannol, PIC; pterostilbene, TPS; trans-stilbene, TS; and trans-stilbene oxide, TSO) to exhibit toxicity towards RAW 264.7 mouse macrophages. The effect of TS, TSO, RES and TPS on RAW 264.7 macrophage viability was determined by two standard methods: (a) the MTT assay and (b) the trypan blue dye exclusion test. Whereas macrophages were more sensitive to PIC (LC50 trypan ∼ 1.3 μM) and to TPS (LC50 trypan ∼ 4.0 μM and LC50 MTT ∼ 8.3 μM) than to RES (LC50 trypan ∼ 8.9 μM and LC50 MTT ∼ 29.0 μM), they were relatively resistant to TSO (LC50 trypan ∼ 61.0 μM and LC50 MTT > 100 μM) and to TS (LC50 trypan ≥ 5.0 μM and LC50 MTT ≥ 5.0 μM). The ability of selected stilbenes (RES, TPS and PIC) to exhibit growth inhibitory effects was also examined. Although RES and TPS were observed to inhibit cell proliferation in macrophages (IC50 ≤ 25 μM), these cells were resistant to growth inhibition by PIC (IC50 ≥ 50 μM). The data obtained in the present analysis demonstrate that substituted stilbene compounds such as RES have the capacity to exhibit cytotoxic and anti-proliferative activities in macrophages.
Over recent years, there has been increasing interest noted in those active substances derived from plants that show potential for preventing cancer development. The most promising candidate is resveratrol which can be found in large amounts in the skin of grapes, tomatoes and in red wine. Its beneficial effects on the human body are seen both in prevention and therapy. The anti-carcinogenic action of resveratrol is linked with its ability to neutralise reactive oxygen species and to modulate cellular processes such as apoptosis, and both cancerous cell proliferation and differentiation. This article presents the characteristics of resveratrol as a bioactive compound derived from natural sources exhibiting anti-cancer properties, which, because of a wide spectrum of biological activities may be used in the prevention of cancer. Many in vitro and animal-based studies have demonstrated such preventative anti-cancer action in the colon, prostate, breast and lungs. The beneficial effects of resveratrol are also presented when adopted as a support to conventional treatments of cancer using chemo- and radio-therapy.
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Kaempferol, but not resveratrol inhibits angiotensin converting enzyme

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Inhibition of angiotensin converting enzyme (ACE) has proved to be beneficial in the treatment of various cardiovascular disorders. The aim of this study was to evaluate ACE inhibitory potential of two polyphenolic compounds with different structures: resveratrol (present in high quantities in French wine) and kaempferol (abundant in greens), using method of liquid chromatography coupled with electrospray ionization mass spectrometry (LC-ESI-MS) for ex vivo measurement of angiotensin I to angiotensin II conversion by ACE in aortic tissue of Wistar-Kyoto rats. In this setting, kaempferol (10-30-100 µM), but not resveratrol (10-30-100 µM) appeared to inhibit dose-dependently conversion of Ang I to Ang II. Although the mechanism of ACE inhibition by kaempferol remains to be elucidated, this observation may help in search or designing of new classes of ACE inhibitors.
Cisplatin (cis-diamminedichloroplatinum II, cisPt) is especially useful in the treatment of epithelial malignancies, however, the use of cisplatin is accompanied by several toxicities including haematological toxicity. Contrary to cisplatin, selenium-cisplatin conjugate ((NH3)2Pt(SeO3); Se-Pt) has only a slight toxicity effect on blood platelet function. In the mechanism of platinum compounds action on platelets thiols are involved. The aim of the present studies was to examine in vitro how trans-resveratrol (trans-3,4',5-trihydroxystilbene) acts on the levels of platelet glutathione (GSH) and other thiol-containing compounds and how, as an antioxidant, protecs blood platelets against the oxidative stress caused by platinum compounds (cisPt and Se-Pt). To analyse the level of thiols in human blood platelets treated with platinum compounds and with resveratrol the classical technique HPLC has been used. Blood platelets isolated by differential centrifugation of human blood were incubated (30 min, 37°C) with cisPt or Se-Pt at dose of 10 µg/ml that inhibits platelet function and with resveratrol (25 µg/ml). The obtained results indicate that platinum compounds caused in platelets a decrease of both, reduced glutathione (GSH) and free thiols of cysteine (CSH) and cysteinylglycine (CGSH). The pool of these compounds in unreduced form was increased. Platinum compounds caused the reduction of platelet protein thiols. Resveratrol (after 30 min action) at the concentration of 25 µg/ml partly reduced the platinum compounds induced decrease of platelet thiols, particularly thiols in acid-soluble fraction.
Resveratrol (3,4',5-trihydroxystilbene), a compound found in many plants, has been shown to prevent coronary heart diseases and to exert a variety of antiinflammatory and anticancerogenic effects. It is effective in lowering the level of serum lipids and in inhibiting platelet aggregation. We evaluated the effect of trans-resveratrol on the production of free radicals in pig blood platelets and showed that resveratrol inhibited the production of different reactive oxygen species (O·2H2O2, singlet oxygen and organic radicals) measured by the luminol-dependent chemiluminescence in resting platelets (P < 0.05). Resveratrol inhibited also the generation of radicals in platelets activated by thrombin (P < 0.05). Treatment of platelets with resveratrol at concentrations of 6.25 and 12.5 μg/ml caused a statistically insignificant increase in the production of O·->2 in these cells, as measured by reduction of cytochrome c; however, at higher doses (25, 50 and 100μg/ml) resveratrol distinctly reduced the generation of O·->2 in platelets (P < 0.05). We suggest that free radicals play an important role in the reduced reactivity of blood platelets induced by resveratrol.
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