Eurycomanoic Acids A-C: Three New Quassinoid Carboxylic Acids from Eurycoma longifolia (Simaroubaceae)

Area of Science:

• Natural Product Chemistry
• Phytochemistry
• Organic Chemistry

Background:

• Eurycoma longifolia Jack (Simaroubaceae) is a plant used in traditional medicine.
• Quassinoids are a class of naturally occurring compounds with diverse biological activities.
• The isolation of new quassinoids contributes to understanding the phytochemical diversity of Eurycoma longifolia.

Purpose of the Study:

• To isolate and characterize new quassinoid compounds from Eurycoma longifolia roots.
• To elucidate the structures and stereochemistry of the isolated compounds.
• To propose a potential biosynthetic pathway for one of the new compounds.

Main Methods:

• Extraction of Eurycoma longifolia roots using 70% methanol.
• Isolation of compounds using chromatographic techniques.
• Structure elucidation using 1D and 2D-NMR, IR, UV spectroscopy, and HR-ESI-MS.
• Stereochemical determination using density functional theory (DFT) calculations.

Main Results:

• Three new C20 quassinoids, eurycomanoic acids A-C (1-3), were isolated.
• The structures were fully elucidated, revealing a tetrahydrofuran ring in the D-ring moiety with specific functional groups at C-15.
• The stereochemistry at C-15 was determined to be S for all three compounds.
• A possible biosynthetic precursor, 15β-hydroxyklaineanone, was identified for eurycomanoic acid A.

Conclusions:

• The study successfully identified and characterized three novel quassinoids from Eurycoma longifolia.
• The findings expand the known chemical constituents of Eurycoma longifolia and contribute to quassinoid research.
• The proposed biosynthetic pathway provides insights into the formation of these compounds within the plant.