Title
Two new flavonoids from Dracaena usambarensis Engl.
Year
2020
Journal
Phytochemistry Letters
Abstract
Investigations of the root extract of Dracaena usambarensis Engl. for anticancer principles led to the characterization of one new homoisoflavonoid, (3S)-3,4ʹ,5,6-tetrahydroxy-7-methoxyhomoisoflavanone (1) and a new retrodihydrochalcone, 4ʹ,4-dihydroxy-2,3-dimethoxydihydrochalcone (2) along with six previously reported compounds, including two homoisoflavonoids, 7-O-methyl-8-demethoxy-3-hydroxy-3,9-dihydropunctatin (3) and loureiriol (4); a phenolic amide, 3-(4ʹʹʹ-hydroxyphenyl)-N-[2ʹ-(4ʹʹ-hydroxyphenyl)-2ʹ-methoxyethyl]acrylamide (5); a spirostane, 25S-spirosta-1,4-dien-3-one (6) and two steroids, stigmasterol (7) and stigmasterol 3-O-β-D-glucopyranoside (8). The structures of 1-8 were determined using spectroscopic and spectrometric techniques. The absolute configurations of compounds 1 and 3 were achieved using circular dichroism spectroscopy. Using the resazurin reduction assay and doxorubicin as reference anticancer drug, 1 showed moderate cytotoxicity against drug sensitive CCRF-CEM but was inactive against all the other tested drug sensitive, resistance phenotypes and normal cells. The crude extract and 2-8 were inactive in the preliminary screening against CCRF-CEM and drug resistant CEM/ADR5000 cell lines. Interestingly, the activity of the standard drug, doxorubicin was comparable to those of inactive compounds against CEM/ADR5000 cells. Future studies should focus on structure modifications of 1-3, in order to obtain more potent analogues.
Instrument
J-715
Keywords
Circular dichroism, Absolute configuration, Natural products, Pharmaceutical