Cancer chemopreventive and antioxidant activities of seed, skin, and pulp of Maximo hybrid grapes (IAC 138-22) at five different ripening stages

Abstract

ABSTRACT: This study evaluated the composition and the cancer chemopreventive and antioxidant activities of the seed, skin, and pulp of Maximo hybrid grapes (IAC 138-22) harvested at different ripening stages. The content of total phenolic compounds and tannins were determined by the Folin-Ciocaulteau method, and total anthocyanins were determined using the differential pH method. Different chemical methods assessed the antioxidant activity. Cell viability (macrophage and melanoma skin cancer) and cancer chemopreventive activity were tested in cell lines by quinone reductase induction assay, TNF-α-induced NF-κB inhibitory activity assay, and aromatase inhibitory activity assay. The hybrid grape had high phenolic contents in both seeds and skin, significantly reduced upon ripening. The results showed that fruit ripening significantly affected both the composition and the antioxidant and cancer chemopreventive activities. Except for the anthocyanin content, the most significant results were observed for green seeds, with the greenest stage showing the best results. The green seeds showed the highest antioxidant activity, even when compared to free resveratrol. In the assessment of cancer chemopreventive activity, the green seeds showed the ability to inhibit N-FκB and aromatase activity, important factors for the early stage of cancer development. Besides, no extracts showed cytotoxicity. Therefore, this grape’s green seeds showed strong antioxidant and cancer chemopreventive activities confirmed herein, suggesting beneficial health effects.