Immunosuppressive decalin derivatives from red yeast rice

Area of Science:

• Natural Product Chemistry
• Immunology
• Organic Chemistry

Background:

• Red yeast rice is a traditional fermented product known for its bioactive compounds.
• Decalin derivatives are a class of organic compounds with diverse biological activities.
• Understanding the immunosuppressive potential of natural products is crucial for developing new therapeutics.

Purpose of the Study:

• To isolate and characterize new decalin derivatives from red yeast rice.
• To investigate the immunosuppressive effects of these novel compounds on human T cell proliferation.
• To identify specific compounds responsible for the observed immunosuppressive activity.

Main Methods:

• Extraction of bioactive compounds from red yeast rice using ethyl acetate.
• Structure elucidation of isolated compounds using Nuclear Magnetic Resonance (NMR) and mass spectrometry.
• In vitro assessment of immunosuppressive activity on human T cell proliferation.

Main Results:

• Five new decalin derivatives and two known compounds were successfully isolated and identified.
• Monascusic lactone A (1) was identified as a novel naturally occurring decalin derivative with a spiro lactone.
• All tested isolates (1-7), particularly monascusic acids B (2), C (3), D (4), A (6), and heptaketide (7), demonstrated dose-dependent suppression of human T cell proliferation.
• The immunosuppressive effects were observed in the concentration range of 10 to 100 μM.

Conclusions:

• This study reports the isolation and characterization of novel decalin derivatives from red yeast rice.
• The findings present the first evidence of immunosuppressive activity associated with decalin derivatives.
• The identified compounds, especially monascusic acids, show potential as therapeutic agents for conditions involving T cell-mediated immune responses.