Flavonoids and their glycosides, including anthocyanins

Recently, considerable scientific and therapeutic interest has focused on the structure and functions of the flavonoids. In a previous study, we suggested that hydroxyl (OH) substitutions on specific carbons in the skeleton of the flavonoids might significantly affect their apoptosis-modulating properties. Here, to investigate the effect of various OH substitutions on their diphenylpropane (C6C3C6) skeleton carbons, we selected 10 different flavonoids and assessed their role on UV-induced apoptosis of human keratinocytes, the principal cell type of epidermis. The results showed that 5,7,3',4'-tetrahydroxylflavanone (eriodictyol) and 3,4'-dihydroxy flavone (3,4'-DHF) had a positive effect on cell proliferation of human HaCaT keratinocytes. Treatment with eriodictyol in particular resulted in significant suppression of cell death induced by ultraviolet (UV) light, a major skin-damaging agent. We found that eriodictyol treatment apparently reduced the percentage of apoptotic cells and the cleavage of poly(ADP-ribose) polymerase, concomitant with the repression of caspase-3 activation and reactive oxygen species (ROS) generation. The anti-apoptotic and anti-oxidant effects of eriodictyol were also confirmed in UV-induced cell death of normal human epidermal keratinocyte (NHEK) cells. Taken together, these findings suggest that eriodictyol can be used to protect keratinocytes from UV-induced damage, implying the presence of a complex structure-activity relationship (SAR) in the differential apoptosis-modulating activities of various flavonoids.

The anti-apoptotic and anti-oxidant effect of eriodictyol on UV-induced apoptosis in keratinocytes.

Design, synthesis and inhibitory activities of naringenin derivatives on human colon cancer cells.

Natural products, including flavonoids, are suggested to be involved in the protective effects of fruits and vegetables against cancer However, studies concerning the effect of flavonoids frequently lacked data regarding to flavanones In this study, we investigated the inhibitory effect of flavanone compounds, including flavanone, 2′-OH flavanone, 4′-OH flavanone, 6-OH flavanone, naringin and naringenin, on cell growth of various cancer cells We determined that flavanone and 2′-OH flavanone inhibited cell growth of A549, LLC, AGS, SK-Hepl and HA22T cancer cells, while other flavanones showed little or no inhibition We evaluated growth-inhibitory activity of flavanone and 2′-OH flavanone against highly proliferative human lung cancer cells (A549) via anchorage-independent and -dependent colony formation assay, and further showed that treatment of flavanone resulted in a G1 cell cycle arrest with reduction of cyclin D, E and cyclin-dependent kinase (CDK) 2, while treatment of 2′-OH flavanone led to a G2/M phase accumulation with reduction of cyclin B, D and Cdc2 Moreover, we demonstrated the improvement effect of flavanone and 2′-OH flavanone with anti-cancer drug, doxorubicin, on A549 cells Finally, flavanone and 2′-OH flavanone were evidenced by its inhibition on the growth of A549 and Lewis lung carcinoma cells in vivo

The tumor-growth inhibitory activity of flavanone and 2′-OH flavanone in vitro and in vivo through induction of cell cycle arrest and suppression of cyclins and CDKs

Eriodictyol-7-O-glucoside, a novel Nrf2 activator, confers protection against cisplatin-induced toxicity

Two new flavanone glucosides, (2S)-homoeriodictyol 7,4′-di-O-β-D-glucopyranoside (4) and (2R)-eriodictyol 7,4′-di-O-β-D-glucopyranoside (5) were isolated from the branches and leaves of Viscum coloratum (KOMAR) NAKAI (Loranthaceae), along with three known flavanone glucosides: (2S)-homoeriodictyol 7-O-β-D-glucopyranoside (1), (2S)-eriodictyol 7-O-β-D-glucopyranoside (2), and (2S)-naringenin 7-O-β-D-glucopyranoside (3). The structures of these compounds were elucidated using spectroscopic methods. The antioxidant activities of these isolated compounds were evaluated by colorimetric methods based on their scavenging effects on hydroxyl radicals and superoxide anion radicals, respectively. All the compounds showed potent albeit varied degrees of antioxidative activities and the structure–activity relationship is discussed.

https://www.jstage.jst.go.jp/article/cpb/54/1/54_1_133/_pdf

Zhi-Xin Liao

Papers

Antioxidative Flavanone Glycosides from the Branches and Leaves of Viscum coloratum