Chemical constituents from Bakeridesia pickelii Monteiro (Malvaceae) and the relaxant activity of kaempferol-3-O-beta-D-(6"-E-p -coumaroyl) glucopyranoside on guinea-pig ileum

The phytochemical investigation of Bakeridesia pickelii Monteiro led to the isolation of seven compounds: beta-sitosterol, a mixture of sitosteryl-3-O-beta-D-glucopyranoside and stigmasteryl-3-O-beta-D-glucopyranoside, vanillic acid, p-coumaric acid, quercetin 3-O-beta-D-glucopyranoside (isoquercitrin) and kaempferol-3-O-beta-D-(6"-E-p -coumaroyl) glucopyranoside (tiliroside), which was isolated as the major component. Their structures were elucidated on the basis of spectroscopic data such as IR, ¹H and 13C NMR, including two-dimensional techniques. Tiliroside relaxed the guinea-pig ileum pre-contracted with KCl 40 mM (EC50 = 9.5 ± 1.0 x 10-5 M), acetylcholine 10-6 M (EC50 = 2.3 ± 0.9 x 10-5 M) or histamine 10-6 M (EC50 = 4.1 ± 1.0 x 10-5 M) in a concentration-dependent manner.

Antioxidant and cytotoxic studies for kaempferol, quercetin and isoquercitrin

The aim of the present study was to investigate a cytotoxic oxidative cell stress related and the antioxidant profile of kaempferol, quercetin, and isoquercitrin. The flavonol compounds were able to act as scavengers of superoxide anion (but not hydrogen peroxide), hypochlorous acid, chloramine and nitric oxide. Although flavonoids are widely described as antioxidants and this activity is generally related to beneficial effects on human health, here we show important cytotoxic actions of three well known flavonoids. They were able to promote hemolysis which one was exacerbated on the presence of hypochlorous acid but not by AAPH radical. Therefore, despite they expected scavenger action over free radicals an oxidants, these compounds could be very lesive to living organisms by acting over erythrocytes and maybe other cellular types.

Conteúdo de miricetina, quercetina e kaempferol em chás comercializados no Brasil

Os teores de miricetina, quercetina e kaempferol foram determinados em uma marca de ban-chá, duas de chá verde e quatro de chá preto. Analisaram-se três lotes para cada marca em duplicata por cromatografia líquida de alta eficiência. Quercetina (2,5-3,4 mg/g folha seca) predominou em todas as amostras, seguida por kaempferol (1,0-2,0 mg/g folha seca), com exceção de uma amostra na qual kaempferol e miricetina tiveram teores iguais. Houve variação entre os tipos de chás e mesmo entre marcas do mesmo tipo. Miricetina (traços - 1,9 mg/g folha seca) foi o flavonol, que mais variou e que esteve em menor nível nos chás pretos. Outros chás muito consumidos no Brasil também foram investigados. A miricetina não foi encontrada em chás de frutas (maçã e morango) e de ervas (erva doce, camomila, erva cidreira, hortelã, boldo, mate e erva mate), enquanto que quercetina foi encontrada em quatro chás (camomila, boldo, morango e erva mate) e kaempferol, em dois chás (boldo e erva-mate), em concentrações de 0,4 a 2,5 e 0,4 a 2,6 mg/g de folha seca, respectivamente. Concluiu-se que estes chás são fontes de flavonóis na dieta brasileira, embora com teores menores que em chás verde e preto.

Estudo fitoquímico e avaliação do potencial antidiabético do Cissus sicyoides L. (Vitaceae)

The effect of hydroalcoholic extracts (HE) obtained from leaves of Cissus sicyoides (CS) on glucose tolerance (GT) was investigated in rats treated with dexametasone (DEX). Our results showed that HE intensified the decreased GT promoted by (DEX). Additionally, the flavonoids kaempferol 3-O-rhamnoside and quercetin 3-O-rhamnoside, obtained from aerial parts of CS, were used to study the incorporation of glucose to glycogen in soleo muscle. The results showed that both flavonoids did not show effect on glycogen synthesis. Thus, our data, in contrast to popular believe, did not reveal antidiabetic activity to SC.

Flavonóides e triterpenos de Baccharis pseudotenuifolia: bioatividade sobre Artemia salina

The phytochemical investigation of the chloroformic and methanolic extracts of the Baccharis pseudotenuifolia led to the isolation of triterpenes, steroids and flavonoids. From chloroformic extract were isolated oleanolic acid and alpha-spinasterol while from methanolic extract were isolated the flavonoids: hispidulin, naringenin, 3'-methoxy-luteolin, apigenin, kaempferol, eriodyctiol, aromadendrin, quercetin, 3'-methoxy-quercetin, quercetin-3-O-rhamnoside and quercetin-3-O-glucoside. The structure of these compounds were identified by IR, CG/MS, ¹H and 13C NMR spectral analysis and comparison with literature. In addition, the extracts were evaluated by means of Brine Shrimp Lethality test and the highier activity was observed in the chloroformic extract.

Flavonóides glicosilados das folhas e flores de Bauhinia forficata (Leguminosae)

From the leaves of Bauhinia forficata kaempferol and four flavonoid glycosides, 3,7-di-O-alpha-L-rhamnopyranosylkaempferol, 3,7-di-O-alpha-L-rhamnopyranosylquercetin, 3-O-[alpha-L-rhamnopyranosyl-(1->6)-beta-D-glucopyranosyl]-7-O-alpha-L-rhamnopyranosylkaempferol and 3-O-[alpha-L-rhamnopyranosyl-(1->6)-beta-D-glucopyranosyl]-7-O-alpha-L-rhamnopyranosylquercetin were obtained. From the flowers only the flavonoid 7-O-alpha-L-rhamnopyranosylkaempferol was isolated. The structures were established by chemical and spectroscopic methods.

Constituintes químicos da casca do caule de Amburana cearensis A.C. Smith

The phytochemical analysis of the ethanol extract trunk bark of Amburana cearensis allowed the isolation and identification of twelve constituents: coumarin, sucrose, two phenol acids (vanillic acid and protocatechuic acid), five flavonoids (afrormosin, isokaempferide, kaempferol, quercetin and 4'-methoxy-fisetin), a phenol glucoside (amburoside A) and a mixture of glucosilated b-sitosterol and stigmasterol. Their structures were elucidated by spectroscopic methods such as IR, MS, ¹H and 13C NMR, including uni and bidimensional techniques, in addition to comparison with literature data.

Constituintes químicos e atividade antioxidante de Sida galheirensiS Ulbr. (Malvaceae)

The phytochemical investigation of Sida galheirensis led to the isolation of 5,4'-dihydroxy-3,7,3´-trimethoxyflavone, 17³-ethoxyphaeoforbide, a rare natural product, 6,7-dimethoxycoumarin, ortho-hydroxybenzoic acid, sitosterol-3-O-beta-D-glucopyranoside, stigmasterol-3-O-beta-D-glucopyranoside, 5,7,4'-trihydroxyflavone, 5,7,3',4'-tetrahydroxyflavone, kaempferol-3-O-beta-D-(6"-E-p-coumaroyl) glucopyranoside and luteolin 7-O-beta-D-glucopyranoside. Their structures were assigned based on spectroscopic analyses, including two-dimensional NMR techniques. Antioxidant activities of hexane, CHCl3, EtOAc, BuOH and EtOH extracts of Sida galheirensis were measured using the 1,2-diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging assay. This is also the first work reporting the chemical investigation of Sida galheirensis.

Ácido canárico (3,4-seco derivado do lupano) em própolis do Ceará

Phytochemical investigation of a propolis sample from Alto Santo - Ceará, Brazil, allowed identification of triterpenes (lupeol, lupenone, germanicone, canaric acid) and flavonoids (quercetin, kaempferol and acacetin), which were identified by spectroscopic data (IR, MS, and NMR, including 2D techniques). This is the first report of canaric acid in propolis. Propolis extract and flavonoids showed antioxidant activity using a DPPH radical scavenging assay.

Compostos polifenólicos do kino de Eucalyptus citriodora

Phytochemical analysis of the kino of Eucalyptus citriodora led to the isolation of 1-O,2-O-digaloil-6-O-trans -p-cumaroil-beta-D-glucopyranoside, 1-O-trans-p-cumaroil-6-O -cinamoil-beta-D-glucopyranoside, alpha and beta 6-O-trans-p-cumaroil-D-glucopyranoside, 7-methylaromadendrin-4'-O-6''- trans-p-cumaroil-beta-D-glucopyranoside, aromadendrin, aromadendrin-7-methyl-ether, naringenin, sakuranetin, kaempferol-7-methyl-ether and galic acid. Structural elucidation of the isolated compounds was established on the basis of spectral data, particularly by the use of 1D NMR and several 2D shift correlated NMR pulse sequences (¹H,¹H-COSY, HMQC, HMBC).

Otimização de método para determinação de flavonóis e flavonas em frutas por cromatografia líquida de alta eficiência utilizando delineamento estatístico e análise de superfície de resposta

This work optimized the HPLC conditions for the simultaneous determination of luteolin, apigenin, myricetin, quercetin and kaempferol in aglycone form, as well defined the best conditions for hydrolysis/extraction of these flavonoids in fruits, using the statistical central composite design and response surface analysis. A reverse phase method was developed using a gradient of methanol/water acidified with 0.3% formic acid as mobile phase and a photodiode array detector. The samples were extracted with methanol/water (50:50 v/v) at 90 ºC. The optimum time and HCl concentration varied for the different fruits investigated, demonstrating the necessity of optimizing these conditions for each fruit analyzed. Good recovery (87.1 to 96.3%), repeatability and linearity were obtained.

químicos das folhas de Qualea grandiflora: atribuição dos dados de RMN de dois flavonóides glicosilados acilados diastereoisoméricos

Phytochemical investigation from leaves of the Qualea grandiflora (Vochysiaceae) resulted in the isolation and identification of kaempferol-3-O-α-L-(4"-E-p-coumaroyl)-rhamnoside, kaempferol-3-O-α-L-(4"-Z-p-coumaroyl)-rhamnoside, squalene, phytol, lupeol, α-amyrin, β-amyrin, sitosterol, sitostenone, sitosterol-3-O-β-D-glucopyranoside, ursolic and oleanolic acids. The structures of the compounds were identified by 1D- and 2D-NMR experiments, mass and UV spectrometry and comparison with literature data.

Constituintes químicos do caule de Senna reticulata Willd. (Leguminoseae): Chemical constituents isolated from the wood of Senna reticulata Willd.

The phytochemical investigation of the wood extracts of Senna reticulata (Leguminoseae) yielded six anthraquinones: chrysophanol, physcion, aloe-emodin, 1,3,8-trihydroxyanthraquinone, 3-methoxy-1,6,8-trihydroxyanthraquinone, emodin and the chrysophanol-10,10' bianthrone. The triterpenes a and b-amirin, the steroids b-sitosterol and stigmasterol as well as the flavonoid kaempferol were also identified. The structures were established by spectral analysis, including two-dimensional NMR techniques. It is the first report of 1,3,8-trihydroxyanthraquinone and 3-methoxy-1,6,8-trihydroxyanthraquinone in higher plants.

Flavonóides, norisoprenóides e outros terpenos das folhas de Tapirira guianensis

From hexane fraction of methanol extract of leaves of Tapirira guianensis (Anacardiaceae) were obtained lupeol, 24-methylenecycloartan-3-ol, phytol, α-amyrin, β-amyrin, sitosterol, sitostenone, glycosyl sitosterol, as well as sitosterol esterified with palmitic and stearic acids. Phytol, α-amyrin and β-amyrin esterified with fatty acids were also identified from same extract. The EtOAc extract besides the norisoprenoids (6S,7E,9S)-6,9-dihydroxy-megastigma-4,7-dien -3-one 9-O-β-glucopyranoside and (6S,7E,9R)-6,9-dihydroxy-megastigma-4,7-dien-3-one 9-O-β-glucopyranoside also afforded kaempferol 3-O-rhamnoside, kaempferol 3-O-arabinofuranoside, quercetin 3-O-rhamnoside, and kaempferol. The structural elucidation of isolated compounds were based on UV, IR, MS, ¹H and 13C NMR data analysis.

First secondary metabolites from Herissantia crispa L (Brizicky) and the toxicity activity against Artemia salina Leach

The phytochemical investigation of Herissantia crispa led to the isolation of seven compounds, identified as: sitosterol 3-O-β-D-glucopyranoside, stigmasterol 3-O-β-D-glucopyranoside, 3,5,7,4'-tetrahydroxyflavone (kaempferol), 3,5,7,3',4'-pentahydroxyflavone (quercetin), unpublished in the genus Herissantia, besides β-sitosterol, kaempferol 3-O-β-D-(6''-E-p-coumaroil) (tiliroside) glucopyranoside and kaempferol 3,7-di-O-α-L-ramnopyranoside (lespedin), described for the first time in the species. The structural determination of the compounds was made by means of spectroscopy methods such as Infrared Spectroscopy, ¹H and 13C Nuclear Magnetic Resonance, with the aid of two dimensional techniques, and by comparison with literature data. The toxicity activity of the MeOH extract and lespedin on Artemia salina Leach. was also carried out.