Investigation of antioxidants present in pomegranate peel and fruit extracts with inhibitory activity on oxidized LDL cholesterol

Aim: Studies have shown that the pomegranate, which grows in many regions of our country, contains numerous bioactive compounds with potent biological effects. This study aimed to determine the total phenolic and flavonoid contents, antioxidant potential, metal chelating capacity, and inhibitory effects against LDL oxidation of pomegranate peel extracts and fruit juice. Material and method: Pomegranate peel and fruit were used in this study. Nonpolar components were removed using Soxhlet extraction, yielding extracts rich in polar bioactive compounds. The total phenolic and flavonoid contents, metal chelating capacity, DPPH radical scavenging activity, and LDL oxidation inhibition potential were determined spectrophotometrically. Results: Pomegranate juice contained a higher total phenolic content (1.034 μg gallic acid equivalent per 1,000 μL) than the peel extract. In contrast, flavonoid content was greater in the peel extract (1.325 μg) than in the juice. The strongest metal chelating activity was observed in the peel extract (IC₅₀ = 0.248 mg/mL). DPPH radical scavenging activity was higher in the juice, while the peel extract exhibited a significantly stronger LDL oxidation inhibitory effect (1% inhibitory concentration = 26.885). Conclusion: Our study findings revealed that pomegranate peel extract exhibited a stronger biochemical effect in inhibiting LDL oxidation than pomegranate juice, attributable to its higher flavonoid content and metal chelating capacity. Pomegranate juice, on the other hand, was found to be superior in terms of total phenolic content and free radical scavenging activity. Overall, pomegranate peel extract appears to be more effective and could find widespread use in the field of complementary medicine.