AUTHOR=Valdés Ernesto , González César , Díaz Katy , Vásquez-Martínez Yesseny , Mascayano Carolina , Torrent Claudia , Cabezas Francisco , Mejias Sophia , Montoya Margarita , Cortez-San Martín Marcelo , Muñoz Marcelo A. , Joseph-Nathan Pedro , Osorio Mauricio , Taborga Lautaro 

TITLE=Biological Properties and Absolute Configuration of Flavanones From Calceolariathyrsiflora Graham

JOURNAL=Frontiers in Pharmacology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2020.01125

DOI=10.3389/fphar.2020.01125

ISSN=1663-9812

ABSTRACT=<p>Flavanones (–)-(2<italic>S</italic>)-5,4’-dihydroxy-7-methoxyflavanone (1) and (–)-(2<italic>S</italic>)-5,3’,4’-trihydroxy-7-methoxyflavanone (2) were isolated from the extracts of <italic>Calceolaria</italic><italic>thyrsiflora</italic> Graham, an endemic perennial small shrub growing in the central zone of Chile. The absolute configuration of these compounds was resolved by optical rotation experiments and <italic>in silico</italic> calculations. Three analogs (3, 4, and 5) were synthesized to do structure-activity relationships with the biological assays studied. Biological tests revealed that only flavanone 2 exhibited a moderate inhibitory activity against the methicillin-resistant strain <italic>S</italic>. <italic>aureus</italic> MRSA 97-77 (MIC value of 50 µg/ml). In addition, flavanone 2 showed a potent, selective, and competitive inhibition of 5-hLOX, which supports the traditional use of this plant as an anti-inflammatory in diseases of the respiratory tract. Also, 2 exhibited cytotoxic and selective effects against B16-F10 (8.07 ± 1.61 µM) but 4.6- and 17-fold lesser activity than etoposide and taxol.</p>