Meta-Analysis of the Antioxidant and Antitumor Effects about Resveratrol in Animal Models with Breast Cancer: Integrative Review for Clinical Study Design

Abstract

Natural compounds are promising adjuvants in various treatments, with lowest rate of harmful effects to the organism, greater tolerance and convenience for patients, especially those undergoing longer treatments of chronic diseases. Breast cancer is the type of cancer that most effects women in the world, being the most frequent cause of cancer death between women. Several chemotherapeutic drugs already standardized for cancer treatment originate from components predominantly extracted from plants. The resveratrol, the main grapes polyphenol, has its antioxidant activity well established in the literature, highlighting its potential antitumor effect. The aim of this work was to synthesize, in a quantitative and qualitative means, data on the effect of resveratrol on breast tumorigenesis, based on in vivo and clinical studies. We performed a computerized search using the keywords. The selection criteria were given in vivo in female rats and mice, comparative experiments of tumor mass before and after treatment with resveratrol, in addition to resveratrol as an adjuvant in synergy with other compounds known in the literature for their antioxidant and/or anti-tumor action. Data collected from studies were structured in spreadsheets and classified according to the substances used, which were distributed into four groups: RSV, RSV+hormone modulators, RSV+antioxidants and RSV+antineoplasics. The percentages were calculated of tumor that remained after the treatment proposed by the study (residual tumor). The results obtained in our meta-analysis in animal models showed that resveratrol has an antineoplastic effect in 85% of studies in female rodents with breast cancer, reaching its highest percentage of antitumor effect with a dosage of 25 mg/kg of resveratrol (reduction tumor rate of 97.8%). Associated with other antioxidants, resveratrol had a synergistic effect on tumor reduction (86.01%), as well as when associated with hormonal modulators (58.33%) and antineoplastic drugs (91%), in addition to having its action potentiated when used together with radiation therapy (89% tumor reduction). Data from clinical studies have shown a reduction in breast tumorigenesis through its already known mechanisms of action, such as selective apoptosis, inhibitors of cell proliferation and inflammatory mediators, in addition to hormonal regulation. Therefore, our statistical and qualitative results showed resveratrol as a potential agent in the prevention or adjuvant treatment of female breast cancer, generally amplifying the antitumor effects when combined with standard treatment.