Anti-Lipogenic Effects of Iridoid-Rich Lonicera caerulea Berry Extracts in a Cortisol-Stimulated Adipocyte Model

Berries of Lonicera caerulea (blue honeysuckle; haskap) have been used since ancient times in traditional medicine in China, Japan, and northern Russia. This study aimed to extract, characterize, and evaluate the biological activity of iridoid-rich fractions from haskap berries using an in vitro adipocyte model. Liquid chromatography-mass spectrometry (UPLC-MS) analysis was performed to quantify the major iridoid distribution among ten haskap cultivars. Two iridoid-enriched extracts were prepared via ultrasonication-assisted ethanolic extraction followed by C₁₈ solid-phase fractionation (Extract 1) and subsequent iridoid concentration (Extract 2). Functional evaluation was carried out using a cortisol-induced 3T3-L1 adipocyte model. UPLC-MS revealed pronounced genotypic variation in iridoid profiles among ten cultivars, with CBS-5 exhibiting the highest total iridoid content (2.42 mg/g dry weight), dominated by loganic acid. UPLC-MS confirmed loganin and loganic acid as the predominant constituents in both extracts. The iridoid-rich extracts significantly attenuated cortisol-induced lipid accumulation and intracellular reactive oxygen species generation in 3T3-L1 adipocytes. Consistently, authentic standards of loganin and loganic acid exhibited pronounced antioxidant and anti-lipogenic activities. Collectively, these findings indicate that iridoid-rich extracts from L. caerulea berries may modulate lipid dysregulation and oxidative stress, supporting their potential development as functional food ingredients or nutraceuticals. PRACTICAL APPLICATIONS: Iridoid-rich haskap berry extracts demonstrate anti-lipogenic and antioxidant effects in adipocytes, highlighting cultivar selection and extraction strategies for developing functional foods or nutraceutical ingredients targeting stress-related lipid dysregulation and metabolic health, with potential applications in disease-prevention formulations and ingredient standardization.