Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/27/2004
Publication Date: 1/17/2005
Citation: Wang, S.Y., Feng, R., Ding, M. 2005. Inhibitory effect on activator protein -1, nuclear factor-kappab, and cell transformation by antioxidant capacity in strawberries (fragaria x ananassa duch). Journal of Agricultural and Food Chemistry. 53:4187-4193 Interpretive Summary: Strawberries are good sources of natural antioxidants. In addition to the usual nutrients such as vitamins and minerals, strawberries are also rich in anthocyanins, flavonoids and phenolic acids. However, little information is available on strawberry antioxidants and their cancer-inhibiting effect. We found that strawberry extracts had high antioxidant enzyme activities and also exhibited anti-cancer activity both on mice and human lung cell lines. Information obtained from this research will be valuable for other scientists and consumers interested in antioxidant compounds in fruit and in improving human health.
Technical Abstract: Strawberries (Fragaria x ananassa Duch.) antioxidant enzymes and the potential inhibitory effects on tetradecanoylphorbol-13-acetate (TPA) or ultraviolet-B (UVB) induced activator protein-1 (AP-1) and Nuclear factor-kappaB (NF-'B) activities, and the inhibitory effect on proliferation and transformation of human and mouse cancer cells were evaluated. Strawberries had high activities of glutathione-peroxidase (GSH-POD), superoxide dismutase (SOD), guaiacol peroxidase (G-POD), ascorbate peroxidase (AsA-POD), and glutathione reductase (GR). Strawberry extracts inhibited the proliferation of human lung epithelial cancer cell line A549 and decreased TPA-induced neoplastic transformation of JB6 P+ mouse epidermal cells. Pretreatment of JB6 P+ mouse epidermal cells with strawberry extract resulted in the inhibition of both UVB- and TPA-induced AP-1 and NF-'B transactivation. Furthermore, strawberry extract also blocked TPA induced phosphorylation of ERKs and UVB-induced phosphorylation of ERKs and JNK kinase in JB6 P+ mouse epidermal cell culture. These results suggest that the ability of strawberries for blocking of UVB-and TPA-induced AP-1- and NF-'B- activation may be due to its antioxidant properties and their ability to reduce oxidative stress. The oxidative events that regulate AP-1- and NF-'B transactivation can be important molecular targets for cancer prevention. The strawberries may be highly effective as a chemopreventive agent that acts by targeting the down-regulation of AP-1 and NF-'B activities, blocking MAPK signaling, and suppression of cancer cell proliferation and transformation.