Triterpenes from the button cactus, Epithelantha micromeris

Area of Science:

• Phytochemistry
• Natural Products Chemistry
• Toxicology

Background:

• Ethanolic extracts from the title plant exhibited toxicity in murine models.
• Investigating the chemical constituents of toxic plant extracts is crucial for understanding their biological activity.

Purpose of the Study:

• To isolate and identify the toxic compounds present in the ethanolic extracts of the title plant.
• To characterize novel chemical entities responsible for the observed toxicity.

Main Methods:

• Extraction of plant material using ethanol.
• Acid hydrolysis of the toxic extracts.
• Isolation of crystalline compounds using chromatographic techniques.
• Structure elucidation using spectroscopic methods (implied).

Main Results:

• Six crystalline compounds were isolated from the toxic extracts.
• Identified compounds include oleanolic acid, methyl machaerinate (known triterpenes), and beta-sitosterol (plant sterol).
• Two new delta9(11)-12-oxooleanene triterpenes, epithelanthic acid and methyl epithelanthate, were postulated.
• A trace triterpene lactone was also detected but not fully characterized.

Conclusions:

• The ethanolic extracts of the title plant contain toxic compounds, including known triterpenes and a sterol.
• Potentially novel triterpenes, epithelanthic acid and methyl epithelanthate, were identified and their structures proposed.
• Further investigation is warranted to fully characterize the trace triterpene lactone and confirm the structures of the new compounds.