In vitro antiplasmodial activity of Brazilian Cerrado plants used as traditional remedies.

Twenty-seven species of native Brazilian Cerrado plants commonly used by traditional healers to treat malaria and other diseases were collected and 204 hexanic and ethanolic extracts were obtained by maceration. The antiplasmodial activity of the extracts was tested in vitro against a chloroquine resistant strain (FcB1) of Plasmodium falciparum, and cytotoxicity against the cell lines L-6 of rats and MRC-5 of human was evaluated. Thirty-two extracts showed significant inhibition rates of Plasmodium falciparum growth and of these six showed cytotoxicity against the cell lines. The strongest antiplasmodial activity was found for the hexanic extracts of Xylopia aromatica root wood (IC(50)=4.7 microg/ml), Xylopia emarginata root bark (IC(50)=4.9 microg/ml), Casearia sylvestris var. lingua leaves, stem wood and stem bark, and root wood and root bark (IC(50) values from 0.9 to 2.3 microg/ml), and Cupania vernalis leaves (IC(50)=0.9 microg/ml); and for the ethanolic extract of Aspidosperma macrocarpon root bark (IC(50)=4.9 microg/ml). However, the best selectivity towards Plasmodium falciparum was observed for the hexanic root bark extract of Matayba guianensis (IC(50) on Plasmodium falciparum=6.1 microg/ml, SI=16.4 for MRC-5) and the ethanolic root bark extract of Aspidosperma macrocarpon (IC(50) on Plasmodium falciparum=4.9 micro/ml, SI=16.2 for MRC-5).

Larvicidal activities against Aedes aegypti of some Brazilian medicinal plants.

Larvicidal activities against Aedes aegypti have been determined in the ethanolic extracts obtained from 51 Brazilian medicinal plants. Eleven of the 84 extracts studied showed significant (LC50 < 100 microg mL(-1)) activities against larvae, with extracts from Annona crassiflora (root bark, LC50 = 0.71 microg mL(-1); root wood, LC50 = 8.94 microg mL(-1)) and Annona glabra (seed, LC50 = 0.06 microg mL(-1)) showing the highest activities. The results obtained should be of value in the search for new natural larvicidal compounds.

Larvicidal activity of some Cerrado plant extracts against Aedes aegypti.

One hundred ninety hexanic and ethanolic extract from 27 plant species from the Cerrado biome of Brazil were tested for larvicidal activity against 3rd-stage Aedes aegypti larvae at 500 microg/ml. Fourteen extracts from 7 species showed activity (>65% mortality) against the larvae. Of these Dugeutia furfuracea, Piptocarpha rotundifolia, Casearia sylvestris var. lingua, Serjania lethalis, and Xylopia aromatica were active at 56.6, 162.31, 232.4, 285.76, and 384.37 microg/ml, respectively. Annona crassiflora and Cybistax antisyphilitica showed activity at 23.06 and 27.61 microg/ml. The larvicidal properties of these species are described for the first time, and may prove to be promising in active chemical compound isolation.

Larvicidal diterpenes from Pterodon polygalaeflorus.

Ethanolic extract from seeds of Pterodon polygalaeflorus (Benth) has been shown to possess significant larvicidal activity against the mosquito Aedes aegypti. Bioassay-guided fractionation of the extract led to the isolation and characterization of the know diterpenoid furans 6alpha-hydroxyvouacapan-7beta,17beta-lactone (1), 6alpha,7beta-dihydroxyvouacapan- 17beta-oic acid (2) and methyl 6alpha,7beta-dihydroxyvouacapan-17beta-oate (3). The structures were established from infrared (IR), ultraviolet (UV), 1H-nuclear magnetic resonance (NMR), 13C-NMR, and mass spectral data: full NMR assignments are presented for compounds 1-3 and the diacetyl derivative of 3. Compounds 1-3 exhibited LC50 values of 50.08, 14.69, and 21.76 microg/mL against fourth-instar Aedes aegypti larvae.

Larvicidal activity of Cybistax antisyphilitica against Aedes aegypti larvae.

The larvicidal activity against Aedes aegypti larvae of a stem wood hexane extract of Cybistax antisyphilitica was evaluated. Bioassay-guided fractionation of the crude extract, monitored by larvicidal assay, led to the isolation of a natural quinone identified as 2-hydroxy-3-(3-methyl-2-butenyl)-1.4-naphthoquinone (lapachol). This compound was quite potent against A. aegypti larvae (LC50 26.3 microg/ml).

Down-modulation of nitric oxide production in murine macrophages treated with crude plant extracts from the Brazilian Cerrado.

Several plant species from the Cerrado biome in Brazil are popularly used as herbal medicines for its reputed analgesic, anti-acid, anti-microbial, anti-inflammatory and anti-tumoral properties, among others. It has been reported that some plant extracts interfere in the production of nitric oxide (NO), an important inflammatory mediator. In the present study, we investigated the effect of hexanic and ethanolic extracts from three plant species on NO production by LPS/IFN-gamma-activated J774 macrophages based on traditional use. The cytotoxic effect of the crude extracts was determined by the thiazolyl blue test (MTT) to measure cell viability. Serjania lethalis stem extracts and Cupania vernalis leaf extracts significantly inhibited NO production, while extracts from Casearia sylvestris var. lingua were inactive or showed low activity on NO production, or were very cytotoxic. The ethanolic stem bark and leaf extracts of Serjania lethalis and Cupania vernalis, respectively, almost completely inhibited the production of NO by J774 macrophages. It can be concluded that the selected extracts are potential sources of active compounds that might be used as anti-inflammatory agents.