The antioxidant activity of four species of the Malvaceae family (Sidastrum micranthum (A. St.-Hil.) Fryxell, Wissadula periplocifolia (L.) C. Presl, Sida rhombifolia (L.) E. H. L and Herissantia crispa L. (Brizicky)) were studied using the total phenolic content, DPPH radical scavenging activity and Trolox equivalent antioxidant capacity (TEAC) assays. The antioxidant activity of the crude extract, phases and two isolated flavonoids, kaempferol 3,7-di-O-α-L-rhamnopyranoside (lespedin) and kaempferol 3-O-β-D-(6''-E-p-coumaroil) glucopyranoside (tiliroside) was determined. The results showed that there is a strong correlation between total polyphenol contents and antioxidant activity of the crude extract of Sidastrum micranthum and Wissadula periplocifolia; however, this was not observed between Sida rhombifolia and Herissantia crispa. The ethyl acetate (EaF) phase showed the best antioxidant effect in the total phenolics, DPPH and TEAC assays, followed by the chloroform (CfF) phase, in most species tested. Lespedin, isolated from the EaF phase of W. periplocifolia and H. crispa may not be responsible for the antioxidant activity due to its low antioxidant activity (IC50: DPPH: 1,019.92 ± 68.99 mg/mL; TEAC: 52.70 ± 0.47 mg/mL); whereas tiliroside, isolated from W. periplocifolia, H. crispa and S. micrantum presented a low IC50 value (1.63 ± 0.86 mg/mL) compared to ascorbic acid in the TEAC assay.

Recebido em 11/7/12; aceito em 30/10/12; publicado na web em 28/2/13 CHEMICAL CONSTITUENTS AND ANTIOXIDANT ACTIVITY OF Byrsonima gardneriana (Malpighiaceae). The phytochemical investigation of Byrsonima gardneriana led to the isolation of five triterpenes and one flavonoid: D:B-Friedoolean-5-en-3-one (1), friedoolean-14-en-3-one (2), friedelan-3-one (3), lup-20(29)-en-3-ol (4), 3β-hydroxiolean-12-ene (5) and 3,3',4',5,7-pentahydroxyflavan (6). Their structures were assigned based on spectroscopic analyses, including two-dimensional NMR techniques and comparison with published spectral data. Antioxidant activities of ethanol extract and phases were measured using the 1,2-diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging assay, evaluation of total phenolic content and trolox equivalent antioxidant capacity (TEAC).Keywords: Byrsonima gardneriana; triterpenes; antioxidant activity. INTRODUÇÃOMalpighiaceae é uma família constituída por ervas, arbustos, árvores ou lianas que compreendem cerca de 75 gêneros, com aproximadamente 1300 espécies.1 Estes são predominantes nas regiões tropicais e subtropicais, especialmente no continente americano. 2,3 No Brasil ocorrem 45 gêneros e aproximadamente 300 espécies.1 Plantas pertencentes à família Malpighiaceae são ricas em substâncias antioxidantes como os taninos e flavonoides. 4 Estudos realizados a partir do extrato clorofórmico de Byrsonima microphylla A. Juss levaram ao isolamento de duas naftoquinonas, que pela primeira vez foram relatadas em Malpighiaceae, além de flavanol e triterpenos (lupenona, β-amirina, betulina e lupeol).5 Há ainda relatos de estudos que evidenciaram a composição química do óleo floral de Byrsonima intermedia. Este óleo floral é rico em ácidos graxos livres e o principal constituinte identificado foi o ácido birsônico. 6O gênero Byrsonima é composto por cerca de 150 espécies e encontrado principalmente a partir do México, difundindo-se por toda América do Sul.5 No Brasil são encontradas no norte, nordeste e região central, podendo também ser encontradas em regiões serranas do Sudeste. São empregadas não apenas na medicina tradicional, mas também no preparo de alimentos como sucos, geleias e licores, principalmente nas regiões norte e nordeste do país.7 Espécies deste gênero são comumente empregadas pela medicina tradicional como antiasmáticas, antitérmicas e no tratamento de infecções da pele. 7,8 No Nordeste brasileiro, ocorrem diversas espécies do gênero Byrsonima, havendo na literatura relatos que reportam a presença de triterpenos em Byrsonima verbascifolia e Byrsonima microphylla, e flavonoides e esteroides em Byrsonima variabilis.9 Vários estudos relatam a química de Byrsonima crassifolia, da qual foram isolados compostos voláteis dos frutos, glicolipídeos, triterpenos, ácidos triterpênicos, catequinas e flavonoides das folhas 10,11 e do tronco, proantocianidinas e taninos.12 Alguns estudos relatam ainda o isolamento de uma mistura de ácido gálico e galato de metila, quercetina-3-O-α-L-piranosídeo e a mistura de quercetina-3-O-β-Dgluc...

Aniba riparia (Nees) Mez. (Lauraceae) is popularly known as "louro", and is found in Amazonia and in the Guianas, its distribution extends to the Andes. Alkamide alkaloids were isolated from its green fruit; they were denominated riparin I (methyl ether of N-benzoyl tyramine), riparin II (methyl ether of N-2-hydroxy-benzoyl tyramine) and riparin III (methyl ether of N-2,6-dihydroxy-benzoyl tyramine) in tribute to the plant. When administered orally and intraperitoneally to mice, riparin I and III are anxiolytic, yet without any sedative or muscle relaxing effects. The present study shows that variables such as extraction solvent, centrifugation force, and centrifugation time, are important in the simultaneous liquid-liquid extraction of riparin I and III from male and female Wistar rat blood in HPLC-UV studies. The study confirms matrix influence on simultaneous recovery and detection of riparin I and III. The effect of rat blood matrix for riparin I was -13.86%, while for riparin III it was -10.94%. The recovery for riparin I was 82.14%, while for riparin III it was 87.42%. The efficiency of the process was 73.25% for riparin I and 77.81% for riparin III, demonstrating an optimal method for simultaneous recovery of riparins I and III from the blood of rats. The matrix effect for rat blood showed values of 10.25% for riparin I and -83.01% for riparin III. Recovery for riparin I was 113.11%, whereas for riparin III it was 13.65%. The process efficiency of this method for female rat blood was 125.88% for riparin I and 2.58% for riparin III. Simultaneous recovery of riparin I and III from the blood of male and female rats using acetonitrile as the precipitating solvent, while centrifuged at 10,000 × g for 10 min demonstrated the importance of the parameters chosen for the extraction/recovery process of different analytes.

Anti-inflammatory activity and participation of the glutamatergic system on the antinociceptive activity of ethyl acetate phase of Herisantia crispa (L.