Taxifolin mitigates oxidative DNA damage in vitro and protects zebrafish (Danio rerio) embryos against cadmium toxicity

• Taxifolin (flavonoids) exhibited potent radical scavenging capacity against in vitro antioxidant assays.
• It effectively protects plasmid DNA against oxidative damage caused by OH radicals.
• In addition it chelates the toxic effect of cadmium (Cd) in dose dependent manner (0.1, 1.0, 10.0 and 100 μM).
• It ameliorates the hatchability, heart rate and enzymatic antioxidants by neutralizing the toxic effect induced by Cd.
• Taxifolin significantly reduced phenotypic abnormalities of Cd in a concentration dependent manner.

Taxifolin (TAX) is a natural source of bioflavonoid found in various conifers. In this study, initially we investigated the antioxidant potential of TAX under in vitro assays such as 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), ferric-ion reducing power (FRAP) and hydroxyl radical (OH). The activities of DPPH, ABTS, FRAP and OH radical levels were significantly inhibited by TAX with an IC50 values of 16.48, 66.34, 18.17 and 11.42 μg/ml, respectively. Secondly, TAX exhibited a strong protection against OH mediated DNA damage on pUC19 plasmid DNA at 1.0 μg/ml. Finally, we evaluated the protective mechanism of TAX against cadmium intoxicated zebrafish embryos (Danio rerio). We found that embryos exposed to 100 μM Cd exhibited significantly reduced survival, delayed hatching and phenotypic abnormalities at 24, 48, 72 and 96 hours post fertilization (hpf). Similarly, Cd intoxicated embryos showed significantly increased cardiac function (131 beats/min) at 60 hpf. Conversely, treatment with TAX (0.1, 1.0 and 10 μM) significantly enhanced the antioxidant enzyme levels (SOD, CAT, GPx and GR) by reducing the lipid peroxidation (MDA) in zebrafish embryos. Collectively, our results concluded that TAX could act as a potent redox scavenger against oxidative DNA damage and also functions as a crucial suppressor of Cd toxicity in zebrafish embryos.

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