Phytochemical content and antioxidant activity in eight citrus cultivars grown in Jeju Island according to harvest time

This study aimed to compare phytochemical content and antioxidant activities of eight diverse citrus cultivars grown in Jeju Island depending on their harvest time owing to their health benefits. Plant peels, flesh, and leaves were extracted, and their flavonoid contents were measured by HPLC. Flavonoid levels were high in peel followed by leaves and juices. It was highest in immature fruits and rapidly declined during ripening. While total phenolic content in all citrus peels and fleshes reduced during ripening, those of leaves did not significantly decrease. Antioxidant activity matched the total phenolic content. This indicates that immature citrus tissues exhibited the highest flavonoid and phenolic content with high antioxidant activity and can be potentially employed as a readily accessible natural antioxidant source.