Potent Antioxidant and DNA-Protective Effects of Aqueous Kiwifruit Extract with Low Toxicity in Zebrafish Embryos

Background: Kiwifruit (Actinidia deliciosa) contains diverse bioactives with antioxidant and cytoprotective properties. Oxidative stress–driven DNA damage contributes to aging and disease, underscoring the need for natural antioxidants that scavenge free radicals and preserve genomic integrity. Yet the DNA-protective capacity of whole-fruit extracts and their in vivo safety remain poorly defined, and, to our knowledge, kiwifruit extract has not been evaluated in a zebrafish model.Objective: We investigated the antioxidant capacity and DNA damage–protective effects of an aqueous flesh kiwifruit extract (AFKE) in vitro and assessed acute developmental toxicity in zebrafish embryos.Materials and Methods: AFKE was prepared by homogenizing fresh fruit in distilled water, followed by ultrasound treatment and filtration. Free-radical scavenging was quantified using hydrogen peroxide (H2O2) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays with ascorbic acid and reagent blanks as controls. DNA protection was assessed by incubating yeast genomic DNA with Fenton’s reagent (H2O2 + Fe2+ in the presence of graded AFKE concentrations, then analyzing band integrity by agarose electrophoresis and densitometry. Zebrafish embryos were exposed to 50–400 mg·mL−1 AFKE (embryo medium control), and survival was recorded at 24, 48, 72, and 96 h post-fertilization (hpf). Embryonic morphology (edema, axial curvature, yolk deformations, hatching) was monitored alongside. LC50 was not reached within the tested range (≤ 400 mg·mL-1 at 96 hpf), so we report concentration–survival profiles rather than an LC50 value. Triplicate experiments were analyzed by ANOVA (p < 0.05).Results and Conclusion: AFKE showed dose-dependent scavenging of H2O2 and DPPH radicals; at 400 mg·mL−1 it removed ~60% H2O2, approaching ascorbic acid. DPPH activity, expressed as quercetin equivalents, increased >5-fold across the dose range. In the anti-Fenton assay, AFKE significantly reduced hydroxyl-induced DNA fragmentation in a concentration-responsive manner, achieving ~25% protection at 400 mg·mL−1. In vivo, embryos maintained >99% viability at ≤100 mg·mL−1 through 24 hpf, whereas 400 mg·mL−1 lowered survival to ~60% at 96 hpf, indicating concentration-dependent toxicity at very high doses. Together, these data indicate that AFKE confers measurable antioxidant and DNA-protective effects with low developmental toxicity at effective in vitro concentrations. This first evaluation of kiwifruit extract in zebrafish supports AFKE as a promising natural antioxidant source