Isoflavonoids and Other Compounds from Psorothamnus arborescens with Antiprotozoal Activities

Abstract

Bioactivity-guided fractionation of the root extract of Psorothamnus arborescens yielded the new isoflavone 5,7,3',4'-tetrahydroxy-2'-(3,3-dimethylallyl)isoflavone (1a) and the new 2-arylbenzofuran 2-(2'-hydroxy-4',5'-methylenedioxyphenyl)-6-methoxybenzofuran-3-carbaldehyde (2), together with seven known compounds, including three isoflavones, fremontin (3a), glycyrrhisoflavone (4a), and calycosin (5), two pterocarpans, maackiain (6) and 4-hydroxymaackiain (7), one triterpene, oleanolic acid (8), and one chalcone, isoliquiritigenin (9). In addition, the structure of the isoflavone fremontin was revised using spectroscopic and chemical methods and was assigned the new structure 3a. The isoflavone 1a and the chalcone 9 displayed leishmanicidal activity with IC50 values of 13.0 and 20.7 microM, respectively, against Leishmania donovani axenic amastigotes. Calycosin (5) exhibited selective toxicity against Trypanosoma brucei brucei (IC50 12.7 microM) compared to L. donovani amastigotes and Vero cells (IC50 100 and 159 microM, respectively). These results prompted us to test a small group of structurally related isoflavones for their antitrypanosomal activities. Genistein and 7,3',4'-trihydroxyisoflavone displayed promising activity (IC50 values 4.2 and 7.1 microM, respectively) and selectivity (IC50 versus Vero cells: 32.9 and 135 microM, respectively). These studies suggest that the isoflavone skeleton deserves further investigation as a template for novel antileishmanial and trypanocidal compounds.

Chemical comparison and classification of Radix Astragali by determination of isoflavonoids and astragalosides

“…The categorized constituents G1, G2, and G5 represented compounds related to calycosin, ononin and astragalosides. These components showed major aspects of biological activities of RA [24][25][26][27][28][29][30][31][32][33], suggesting that it is practical to use the categorized constituents for quality assessment. The highest contents of G1, G2 and total isoflavonoids were found in samples from Heilongjiang.…”

Pterocarpans: interesting natural products with antifungal activity and other biological properties

“…Ingham (1979d) Platymiscium floribundum Militao et al (2005) Phytochem Rev (2008) 7:125-154 139 Maximo and Lourenco (1998) Barrero et al (1997) O. spinosa Fujise et al (1965) Phytochem Rev (2008 anti-inflammatory activity (Selvam et al 2004) and their ability to act as antiparasitic agents (Chanphen et al 1998;Salem and Werbovetz 2006). …”

Natural Products from Plants as Drug Candidates and Lead Compounds Against Leishmaniasis and Trypanosomiasis

“…In another study, the flavonoids 3-methylquercetin (14), 3,6-dimethylquercetagetin (15), 7,3´-dimethylluteolin, and 3,6,7,3´-tetramethylquercetagetin showed weak activity against T. cruzi trypomastigotes with IC 50 values of 128, 138, 145, and 102 µg/mL, respectively [43]. The isoflavone calycosin (16), isolated from Psorothamnus arborescens (Fabaceae), exhibited selective toxicity against T. b. brucei bloodstream forms (IC 50 value of 12.7 µM) compared to L. donovani amastigotes and Vero cells (IC 50 100 and 159 µM, respectively) [44].…”