Radioprotective effects of ethanolic extract from walnut kernel internal septum on lethal X-ray exposure in Wistar...

This study assessed the radioprotective efficacy of an ethanolic extract from the walnut kernel internal septum (Juglans regia L.) in Wistar rats exposed to a lethal X-ray dose of 6.73 Gy. The extract was administered at 400, 1600, or 6400 mg/kg, either 2 h before (pre-treatment, n = 7 per group) or after (post-treatment, n = 9 per group) irradiation, with survival monitored over 30 and 60 days. In pre-treated rats, the high dose (6400 mg/kg) consistently provided full protection, surpassing radiation-only controls which showed significant mortality (42.9 ± 7 % at 30 days and 28.5 ± 7 % at 60 days survival rates). Low dose (400 mg/kg) showed reduced efficacy, especially over time. Post-treatment groups also benefited from the high dose, maintaining 100 % survival, whereas radiation-only controls had higher mortality (77.8 ± 6 % at 30 days and 22.2 ± 6 % at 60 days survival rates). Medium and low doses post-treatment yielded partial benefits, with survival ranging from 22.2 % to 44.4 % by day 60. These dose-dependent effects suggest that antioxidants, likely phenolics or flavonoids, mitigate radiation-induced oxidative damage, with 6400 mg/kg providing a critical threshold for efficacy. Safe up to this dose, the extract outperforms other walnut components and synthetic radioprotectors in tolerability and potency. However, lower-dose variability and lack of chemical profiling highlight areas for further research. This novel septum extract emerges as a promising, natural radioprotector for applications in medical radiation safety and emergency scenarios, warranting investigation into its active compounds and mechanisms.