Strawberry (Fragaria × ananassa) and Kiwifruit (Actinidia deliciosa) Extracts as Potential Radioprotective Agents: Relation to Their Phytochemical Composition and Antioxidant Capacity

Ionising radiation is an important form of treatment for human cancer; however, the side effects associated with oxidative damage caused by radiation compromise its effectiveness. This work aimed to quantify the major bioactive components of freeze-dried kiwifruit (KD) and strawberry (SD) extracts and assess their potential efficacy as radioprotective agents in human blood lymphocytes. Their possible genotoxic and cytotoxic effects were also evaluated. The study was conducted by pre-treating human lymphocytes with KD and SD (50, 400, and 800 µg/mL) before radiation at 2 Gy. The results showed that SD presented a higher antioxidant capacity (12.6 mmol Trolox equivalents/100 g db) and higher values of total phenolic compounds (2435 mg of gallic acid equivalents/100 g db), while KD had the highest vitamin C content (322 mg ascorbic acid/100 g db). Regarding phenolic compounds, pelargonidin-3-glucoside was the most abundant in SD (1439 mg/1000 g db) and quercetin-3-O-galactoside in KD (635 mg/1000 g db). None of the tested concentrations of both fruit extracts showed a genotoxic effect. SD (800 µg/mL) reduced the sister chromatid exchange frequency and mitotic index. The efficacy of KD (400 and 800 µg/mL) in lowering the dicentric chromosome frequency demonstrated its radioprotective activity.