Two new 2'-oxygenated flavones from Andrographis elongata

Area of Science:

• Phytochemistry
• Natural Product Chemistry
• Organic Chemistry

Background:

• Andrographis elongata is a plant species known for its potential medicinal properties.
• Flavonoids are a diverse class of plant secondary metabolites with various biological activities.
• Previous phytochemical investigations of Andrographis species have identified several bioactive compounds.

Purpose of the Study:

• To isolate and characterize novel and known flavones from the whole plant of Andrographis elongata.
• To elucidate the chemical structures of the isolated compounds using comprehensive spectroscopic methods.

Main Methods:

• Isolation of compounds using chromatographic techniques.
• Structure elucidation employing Fast Atom Bombardment Mass Spectrometry (FAB-MS).
• Detailed analysis using 1D and 2D Nuclear Magnetic Resonance (NMR) spectroscopy, including COSY, HSQC, HMBC, and ROESY experiments.
• Confirmation through chemical studies.

Main Results:

• Two new 2'-oxygenated flavones, 5,2',6'-trihydroxy-7-methoxyflavone and skullcapflavone I 2'-O-beta-D-(4"-E-cinnamyl) glucopyranoside, were identified.
• Three known flavones, 7-O-methylwogonin, skullcapflavone I, and skullcapflavone I 2'-O-beta-D-glucopyranoside, were also isolated.
• The structures of all five compounds were definitively determined through extensive spectroscopic and chemical analyses.

Conclusions:

• The phytochemical investigation of Andrographis elongata yielded a total of five flavones, including two novel compounds.
• The study contributes to the understanding of the chemical diversity of flavonoids in the Andrographis genus.
• The characterized compounds may serve as leads for further pharmacological research.