Ganolearic Acid A, a Hexanorlanostane Triterpenoid with a 3/5/6/5-Fused Tetracyclic Skeleton from Ganoderma cochlear

Area of Science:

• Natural Product Chemistry
• Organic Chemistry
• Pharmacology

Background:

• Ganoderma species are known sources of bioactive compounds.
• Triterpenoids, particularly seco-nortriterpenoids, exhibit diverse biological activities.
• The structural complexity of Ganolearic acid A presents a unique chemical challenge.

Purpose of the Study:

• To isolate and characterize novel seco-nortriterpenoids from Ganoderma cochlear.
• To elucidate the structure of Ganolearic acid A and fornicatin M.
• To evaluate the anti-inflammatory properties of the isolated compounds.

Main Methods:

• Liquid chromatography-ultraviolet/mass spectrometry (LC-UV/MS)-guided isolation.
• 1D and 2D Nuclear Magnetic Resonance (NMR) spectroscopy.
• High-resolution mass spectrometry (HRMS), Infrared (IR) spectroscopy, and electronic circular dichroism (ECD) calculations.

Main Results:

• Ganolearic acid A (1), a rare 3,4-seco-hexanortriterpenoid with a 3/5/6/5 tetracyclic system, was isolated in trace amounts.
• A new 3,4-seco-nortriterpenoid, fornicatin M (2), and its biogenetic precursor, fornicatin D (3), were identified.
• The complete stereochemical structure of Ganolearic acid A was established using comprehensive spectroscopic and computational methods.

Conclusions:

• The study successfully isolated and characterized novel triterpenoids from Ganoderma cochlear.
• A plausible biogenetic pathway for Ganolearic acid A and fornicatin M was proposed.
• The isolated compounds demonstrated potential anti-inflammatory activities, warranting further investigation.