Comparative Study on the Bioactivities and Marker Compound Contents of Citrus reticulata and Jeju-native Citrus sunki Peels

The peel of Citrus has traditionally been used as a herbal medicine known as Chenpi, with Citrus reticulata officially listed in the Korean Pharmacopoeia for its antioxidant, anti-inflammatory, and digestive benefits. However, much of the Chenpi used in Korea is imported from China, and current pharmacopoeial standards include only C. reticulata and C. unshiu, limiting the use of native Korean citrus varieties. This study aimed to evaluate the potential of Citrus sunki, a native citrus species from Jeju Island, for inclusion in the Korean Pharmacopoeia, based on the Swingle and Tanaka classification systems. The Swingle system, which classifies C. sunki as C. reticulata, was used as a basis to provide scientific evidence for its inclusion through a comparison of their biological activities. DNA sequencing identified the Jeju-native variety Jingyul as C. sunki, while commercial Chenpi products and other Jeju citrus peels were identified as C. reticulata. HPLC analysis showed that C. sunki contained hesperidin levels comparable to or higher than those of C. reticulata. Furthermore, C. sunki demonstrated equivalent or superior antioxidant, skin-whitening, anti-wrinkle, and anti-inflammatory activities. These findings suggest that C. sunki has comparable therapeutic potential to Chenpi, supporting its inclusion in the Korean Pharmacopoeia. The study also underscores the importance of an integrative classification approach considering pharmacological efficacy in evaluating herbal medicines.