Isorugosiformins A-F, six ent-kaurane diterpenoids from Isodon rugosiformis

Area of Science:

• Natural Products Chemistry
• Organic Chemistry
• Phytochemistry

Background:

• Isodon rugosiformis is a plant species known for its rich phytochemical profile.
• Diterpenoids, particularly ent-kaurane derivatives, are a significant class of natural products with diverse biological activities.
• The exploration of novel compounds from medicinal plants remains crucial for drug discovery.

Purpose of the Study:

• To isolate and characterize new ent-kaurane diterpenoids from Isodon rugosiformis.
• To elucidate the chemical structures of these novel compounds using advanced spectroscopic techniques.
• To determine the absolute configuration of the isolated compounds, contributing to the understanding of diterpenoid stereochemistry.

Main Methods:

• Isolation of compounds using chromatographic techniques.
• Structure elucidation via extensive spectroscopic data interpretation (NMR, MS).
• Confirmation of structure and absolute configuration through single crystal X-ray diffraction and quantum chemical calculations of NMR parameters.

Main Results:

• Six new ent-kaurane diterpenoids, designated isorugosiformins A-F (1-6), were successfully isolated.
• The complete structures of isorugosiformins A-F were determined.
• The absolute configuration of compound 5 was established as 6R, representing a novel stereochemical outcome for this class of diterpenoids.

Conclusions:

• The study successfully identified and characterized six new ent-kaurane diterpenoids from Isodon rugosiformis.
• The findings expand the known structural diversity within the ent-kaurane diterpenoid class.
• The determination of the absolute configuration provides valuable insights into the stereoselective biosynthesis and chemical space of these natural products.