Three new saponins from Tribulus terrestris

Area of Science:

• Phytochemistry
• Natural Products Chemistry
• Organic Chemistry

Background:

• Tribulus terrestris L. (Zygophyllaceae) is a plant known for its medicinal properties.
• The phytochemical investigation of medicinal plants is crucial for discovering novel bioactive compounds.

Purpose of the Study:

• To isolate and elucidate the structures of new steroidal saponins from Tribulus terrestris L.
• To characterize the chemical constituents of Tribulus terrestris.

Main Methods:

• Isolation of compounds using chromatographic techniques.
• Structure elucidation employing 1D and 2D Nuclear Magnetic Resonance (NMR) spectroscopy (13C-1H COSY, HMQC, HMBC, 1H-1H COSY, TOCSY, NOESY).
• Mass spectrometry (Fast Atom Bombardment Mass Spectrometry - FABMS, Electrospray Ionization Mass Spectrometry - ESIMS) and chemical methods were utilized.

Main Results:

• Three new steroidal saponins, designated 1-3, were isolated and structurally characterized.
• The structures of the new compounds were determined as hecogenin 3-O-beta-xylopyranosyl(1-->3)-beta-glucopyranosyl(1-->4)-beta-galactopyranoside (1), hecogenin 3-O-beta-glucopyranosyl(1-->2)-beta-glucopyranosyl(1-->4)-beta-galactopyranoside (2), and 3-O-[beta-xylopyranosyl(1-->2)-[beta-xylopyranosyl(1-->3)]-beta-glucopyranosyl(1-->4)-[alpha-rhamnopyranosyl(1-->2)]-beta-galactopyranosyl]-26-O-beta-glucopyranosyl-22-methoxy-(3 beta,5 alpha,25R)-furostan-3,26-diol (3).
• Five known steroidal saponins, L-mannitol, and an inorganic salt were also identified.

Conclusions:

• The study successfully identified and characterized novel steroidal saponins from Tribulus terrestris.
• The findings expand the knowledge of the chemical diversity of Tribulus terrestris.
• The detailed structural information provides a basis for further pharmacological investigations.