Trypanocidal activity of coumarins and styryl-2-pyrones from Polygala sabulosa A.W. Bennett (Polygalaceae)

• Published in: Revista brasileira de farmacognosia 2008-06, Vol.18 (2), p.177-182
• Main Authors: Pizzolatti, Moacir G., Mendes, Beatriz G., Cunha Jr, Anildo, Soldi, Cristian, Koga, Adolfo H., Eger, Iriane, Grisard, Edmundo C., Steindel, Mário
• Format: Article
• Language: English
• Subjects: PHARMACOLOGY & PHARMACY
• ISSN: 0102-695X; 1981-528X; 0102-695X
• DOI: 10.1590/S0102-695X2008000200006

Bioactivity of fractions and compounds obtained from Polygala sabulosa against Trypanosoma cruzi epimastigote, blood trypomastigote and amastigote forms were evaluated in vitro. Dichloromethane and ethyl acetate fractions showed a strong trypanocidal activity on epimastigotes (IC50 < 10.4 µg/mL). Chromatographic analysis by TLC of these fractions confirmed the presence of previously described compounds (dihydrostyryl-2-pyrones, styryl-2-pyrones and 6-methoxy-7-prenyloxycoumarin). The dichloromethane fraction was fractioned by silica gel column chromatography to afford the compound α-spinasterol and the ethyl acetate fraction yielded apigenin, quercetin and a quercetin-3-O-glucoside, being the first description for the Polygala genus. 4-Methoxy-6-(11,12-methylenedioxy-14-methoxydihydrostyryl)-2-pyrone, 4-methoxy-6-(11,12-dimethoxystyryl)-2-pyrone, 6-methoxy-7-prenyloxycoumarin and quercetin-3-O-glucoside showed a weak activity against blood trypomastigotes (IC50 < 1008.6 µg/mL). The prenylated coumarin was the most active compound against both epimastigote and trypomastigote forms, IC50 10.5 and 88.2 µg/mL, respectively. The hemolytic activity and cell toxicity of each active compound was also assessed. Furthermore, 4-methoxy-6-(11,12-methylenedioxy-14-methoxydihydrostyryl)-2-pyrone and 6-methoxy-7-prenyloxycoumarin reduced 4 times the T. cruzi infection rate for Vero cells at 100 and 50 µg/mL, respectively. These results show for the first time active compounds against T. cruzi in P. sabulosa.