Megastigmane glucosides from Equisetum debile and E. diffusum.

Area of Science:

• Phytochemistry
• Natural Products Chemistry
• Organic Chemistry

Background:

• Equisetum species are known sources of diverse bioactive compounds.
• Megastigmane glycosides are a class of natural products with various reported biological activities.
• Previous studies have identified several compounds from Equisetum species, but further investigation is ongoing.

Purpose of the Study:

• To isolate and characterize novel compounds from the aerial parts of Equisetum debile and Equisetum diffusum.
• To revise the absolute configuration of a known compound, debiloside A.
• To compare the chemical constituents of E. debile and E. diffusum.

Main Methods:

• Isolation of compounds using chromatographic techniques.
• Structure elucidation using spectroscopic methods (NMR, MS).
• Determination of absolute configurations.

Main Results:

• A new megastigmane diglucoside, (3S,5R,6S,7E,9S)-megastigman-7-ene-5,6-epoxy-3,9-diol 3,9-O-beta-D-diglucopyranoside, was isolated from E. debile.
• The absolute configuration at C-6 of debiloside A was revised to 6R.
• Several known compounds, including macarangioside D, sammangaoside A, and kaempferol derivatives, were identified from both species.
• A megastigmane derivative isolated from E. diffusum was found to be identical to corchoionoside A.

Conclusions:

• The study successfully isolated and characterized a new megastigmane diglucoside from Equisetum debile.
• The structural revision of debiloside A provides a more accurate understanding of its stereochemistry.
• Comparative analysis of E. debile and E. diffusum reveals overlapping and distinct phytochemical profiles.