Glycosides from Bougainvillea glabra

Area of Science:

• Natural Product Chemistry
• Phytochemistry
• Organic Spectroscopy

Background:

• Bougainvillea glabra is a plant species with potential for novel bioactive compound discovery.
• Glycosides are a class of compounds often found in plants with diverse biological activities.
• Elucidating the structures of plant metabolites is crucial for understanding their properties.

Purpose of the Study:

• To isolate and characterize glycosides from Bougainvillea glabra.
• To determine the chemical structures of the isolated compounds using spectroscopic methods.
• To identify any novel natural products within the plant extract.

Main Methods:

• Isolation of glycosides from Bougainvillea glabra using chromatographic techniques.
• Structure elucidation employing extensive 1D and 2D Nuclear Magnetic Resonance (NMR) spectroscopy, including proton ((1)H) and carbon-13 ((13)C) NMR.
• Comparison of spectral data with known compounds to identify novel structures.

Main Results:

• Three glycosides were successfully isolated from the plant material.
• Compound 1 identified as momordin IIc (quinoside D), a known oleanane triterpene glycoside.
• Compound 2 identified as quercetin 3-O-alpha-L-(rhamnopyranosyl)(1 --> 6)-[alpha-L-rhamnopyranosyl(1 --> 2)]-beta-D-galactopyranoside.
• Compound 3 identified as a new natural product, a caffeoyl derivative of Compound 2: quercetin 3-O-alpha-L-(4-caffeoylrhamnopyranosyl)(1 --> 6)-[alpha-L-rhamnopyranosyl(1 --> 2)]-beta-D-galactopyranoside.

Conclusions:

• The phytochemical investigation of Bougainvillea glabra led to the isolation and structural determination of three glycosides.
• A novel caffeoyl derivative of a quercetin glycoside was discovered, contributing a new natural product to chemical knowledge.
• The study highlights the potential of Bougainvillea species as a source of structurally diverse glycosides.