Sesquiterpenoids of Aucklandia lappa: Phytochemistry, bioactivities and synthesis.

Aucklandia lappa Decne., a traditional medicinal plant, which contains abundant sesquiterpenoids as its main bioactive components, making it widely used in treating gastrointestinal, inflammatory, and respiratory system diseases. This review provides a comprehensive summary of the phytochemistry, bioactivities, and synthesis of sesquiterpenoids isolated from A. lappa. Based on structural classifications, sesquiterpenoids are systematically categorized into types such as eudesmane, guaiane, germacrene, bisabolane, and sesquiterpenoid dimers, etc. The pharmacological profiles of these compounds are extensively discussed, highlighting their significant anti-inflammatory, anticancer, antioxidant, and antimicrobial activities, with a particular focus on key compounds such as costunolide, dehydrocostus lactone, alantolactone, and santamarine. Recent advances in the total synthesis of representative sesquiterpenoids are also reviewed, underscoring the synthetic challenges and strategies. This review aims to consolidate existing knowledge, identify research gaps, and propose future directions for the development of sesquiterpenoid-based therapeutics.