Asperienes A-D, Bioactive Sesquiterpenes from the Marine-Derived Fungus Aspergillus flavus

Area of Science:

• Marine natural products chemistry
• Fungal secondary metabolites
• Organic chemistry

Background:

• Marine-derived fungi, particularly Aspergillus species, are a source of novel bioactive compounds.
• Aspergillus flavus is known for mycotoxin production, but minor components may possess unique bioactivities.
• Limited research exists on the specific C-6'/C-7' epimeric drimane sesquiterpene esters from marine A. flavus.

Purpose of the Study:

• To isolate and characterize novel drimane sesquiterpene esters from a marine-derived Aspergillus flavus strain.
• To determine the absolute configurations of the isolated compounds.
• To evaluate the bioactivities and toxicities of the isolated compounds.

Main Methods:

• Cultivation of marine fungus Aspergillus flavus CF13-11 on solid medium.
• Isolation and purification of compounds using chromatographic techniques.
• Structure elucidation using electronic circular dichroism (ECD) and Snatzke's methods.
• Bioactivity screening against four cell lines and toxicity assessment on normal GES-1 cells.

Main Results:

• Four C-6'/C-7' epimeric drimane sesquiterpene esters, asperienes A-D (1–4), were isolated.
• The absolute configurations of asperienes A-D were successfully assigned.
• This marks the first successful separation of two pairs of C-6'/C-7' epimeric drimane sesquiterpene esters.
• Compounds 1–4 exhibited potent cytotoxic activities with IC₅₀ values between 1.4 and 8.3 μM.
• Asperienes A (1) and D (4) showed lower toxicity to normal GES-1 cells compared to asperienes B (2) and C (3).

Conclusions:

• Marine-derived Aspergillus flavus CF13-11 produces novel epimeric drimane sesquiterpene esters.
• Asperienes A-D possess significant cytotoxic potential against cancer cell lines.
• Compounds 1 and 4 demonstrate a favorable toxicity profile, indicating promise as potential antitumor drug leads.