Identification of a novel triterpene saponin from seeds, pseudoginsenoside RT, and its antiinflammatory activity.

Background: Meyer (Araliaceae) is a highly valued medicinal plant in Asian regions, especially in Korea, China, and Japan. Chemical and biological studies on have focused primarily on its roots, whereas the seeds remain poorly understood. This study explores the phytochemical and biological properties of compounds from seeds.

Methods: seeds were extracted with methanol, and 16 compounds were isolated using various chromatographic methods. The chemical structures of the isolates were determined by spectroscopic data. Antiinflammatory activities were evaluated for triterpene and steroidal saponins using lipopolysaccharide-stimulated RAW264.7 macrophages and THP-1 monocyte leukemia cells.

Results: Phytochemical investigation of seeds led to the isolation of a novel triterpene saponin, pseudoginsenoside RT along with 15 known compounds. Pseudoginsenoside RT exhibited more potent antiinflammatory activity than the other saponins, attenuating lipopolysaccharide-mediated induction of proinflammatory genes such as interleukin-1β, interleukin-6, inducible nitric oxide synthase, cyclooxygenase-2, and matrix metalloproteinase-9, and suppressed reactive oxygen species and nitric oxide generation in a dose-dependent manner.

Conclusion: These findings indicate that pseudoginsenoside RT has a pharmaceutical potential as an antiinflammatory agent and that seeds are a good natural source for discovering novel bioactive molecules.