In vitro antileishmanial and antitrypanosomal activities of flavanones from Baccharis retusa DC. (Asteraceae)

Abstract

Leishmaniasis and Chagas' are parasitic protozoan diseases that affect the poorest population in the world, causing a high mortality and morbidity. As a result of highly toxic and long-term treatments, novel, safe and more efficacious drugs are essential. In this work, the CH(2)Cl(2) phase from MeOH extract from the leaves of Baccharis retusa DC. (Asteraceae) was fractioned to afford two flavonoids: naringenin (1) and sakuranetin (2). These compounds were in vitro tested against Leishmania spp. promastigotes and amastigotes and Trypanosoma cruzi trypomastigotes and amastigotes. Compound 2 presented activity against Leishmania (L.) amazonensis, Leishmania (V.) braziliensis, Leishmania (L.) major, and Leishmania (L.) chagasi with IC(50) values in the range between 43 and 52 μg/mL and against T. cruzi trypomastigotes (IC(50)=20.17 μg/mL). Despite of the chemical similarity, compound 1 did not show antiparasitic activity. Additionally, compound 2 was subjected to a methylation procedure to give sakuranetin-4'-methyl ether (3), which resulted in an inactive compound against both Leishmania spp. and T. cruzi. The obtained results indicated that the presence of one hydroxyl group at C-4' associated to one methoxyl group at C-7 is important to the antiparasitic activity. Further drug design studies aiming derivatives could be a promising tool for the development of new therapeutic agents for Leishmaniasis and Chagas' disease.

Oleanonic acid from Lippia lupulina (Verbenaceae) shows strong in vitro antileishmanial and antitrypanosomal activity

“…In another report, this flavanone isolated from Baccharis retusa showed in vitro activity against T. cruzi trypomastigotes (IC 50 20.2 µg mL -1 ) (Grecco et al 2012). Similar results were observed for sakuranetin (5) in our experiments against epimastigote forms of T. cruzi Y strain (IC 50 47.5 µg mL -1 , Table 2).…”

“…It is noteworthy that such flavonoids were previously detected in the ethanol extract from L. sidoides leaves and might therefore be related to its leishmanicidal activity (Funari et al 2012a). Grecco et al (2012) reported IC 50 51.9 µg mL -1 for sakuranetin (5) isolated from Baccharis retusa against promastigotes of L. amazonensis, which is similar to the results from our experiments against the same type of protozoa (Table 2). Asebogenin (3) isolated from an extract of Piper elongatum aerial parts was described by Hermoso et al (2003) as more active against promastigote forms of L. braziliensis, L. tropica and L. infantum (IC 50 28.5, 3.8 and 6.3 µg mL -1 , respectively) than the observed inhibition against L. amazonensis promastigotes (IC 50 47.5 µg mL -1 , Table 2) in our experiments.…”

Antiprotozoal activity of extracts and isolated triterpenoids of ‘carnauba’ (Copernicia prunifera) wax from Brazil

“…The tested extracts/ compounds were added up to 200 lg/mL concentration while groups from bioactivity-guided fractionation were tested at unique concentration (200 lg/mL). After incubation for 48 h at 24 C, the viability of promastigotes was verified by the colorimetric MTT assay (Grecco et al 2012). Promastigotes incubated without compounds were used as control (100% viability) and wells without cells as blank.…”

“…Despite this knowledge, few studies have evaluated biological activity of 'carnauba' wax, including defensive proteins with antifungal activity (Cruz et al 2002). As part of our continuous project involved in the discovery of antiprotozoal compounds from Brazilian plant species (Grecco et al 2012;Rea et al 2013;Morais et al 2014;Costa-Silva et al 2015), the present work was aimed to identify antiprotozoal metabolites of C. prunifera wax (types 1 and 4) as well as the evaluation of their mammalian cytotoxicity. As a result, three bioactive dammarane-type triterpenoids: (24R Ã )-methyldammar-25-ene-3b,20-diol (carnaubadiol, 1), (24R Ã )-methyldammara-20,25-dien-3-one (2) and (24R Ã )-methyldammara-20,25-dien-3a-ol (3) were characterized.…”

Anti-trypanosomal activity of 1,2,3,4,6-penta-O-galloyl-β -D-glucose isolated from Plectranthus barbatus Andrews (Lamiaceae)

“…21 Also, these drugs are ineffective against the chronic phase of the disease demonstrating the urgent need for new drugs. 20 In our continuing search for anti-parasitic natural products from Brazilian plants, [22][23][24] the crude MeOH extract from leaves of P. barbatus displayed in vitro anti-trypanosomal activity and was subjected to bioactivity-guided fractionation. Using several chromatographic procedures, the compound 1,2,3,4,6-penta--O-galloyl-b-D-glucose (PGG) was isolated for the first time in the Plectranthus genus, identified after NMR and LRESIMS analysis.…”