LONICERA CAERULEA L. BERRIES: A RICH SOURCE OF BIOACTIVE COMPOUNDS AND HEALTH BENEFITS

Abstract

Two new biflavonoids, loniceraflavone A and loniceraflavone B, have been isolated from the aerial parts of Lonicera japonica along with five known compounds: luteolin, luteoloside, quercetin, rutin, and apigenin. The structures of the new biflavonoids were elucidated using detailed spectroscopic methods, including UV, IR, 1D and 2D NMR (¹H, ¹³C, DEPT, COSY, HSQC, and HMBC), and mass spectrometry (ESI-QTOF-MS). The compounds were found to be linked through C–C and C–O–C bonds between flavonoid units. These biflavonoids represent a rare class of natural products in the Caprifoliaceae family. The antioxidant activity of the isolated compounds was also evaluated using DPPH radical scavenging assay, and the new biflavonoids demonstrated significant free radical scavenging activity, comparable to standard antioxidants. The study contributes to the phytochemical understanding of Lonicera japonica, a plant known for its traditional use in Chinese medicine.