INTRODUCTIONThe Lauraceae family comprises 52 genera and approximately 3000 species, mostly from tropical and warm subtropical regions of the world.1 Lauraceae species present several groups of secondary metabolites, most of them aromatic, which seem to be relevant for chemotaxonomic classification in Lauraceae. 2The genus Ocotea comprises ca. 350 species. Previous phytochemical studies have revealed the presence of neolignans, benzylisoquinoline alkaloids, phenylpropanoids, flavonoids and sesquiterpenes, 3 besides a variety of volatile components from its essential oils.1 Ocotea elegans is known as canela de ferro or canela preta in Brazil where it is widespread. Despite its huge distribution, the only study performed on O. elegans reports the isolation of neolignans from the stems by using countercurrent chromatography. 4 Ocotea corymbosa is popularly known as canela de corvo or canela fedorenta in Brazil and its wood is employed in the civil construction industry. 5 Only two studies were performed on O. corymbosa; monoterpenes and sesquiterpenes as well as phytosterols were isolated from the unripe fruits 3 and sesquiterpenes with calamenene skeleton were characterized from its bark. Persea is a genus that comprises ca. 200 species, the most well studied of these being P. americana Mill, known as "avocado fruit". Previous phytochemical studies on avocado seeds identified various classes of natural products such as phytosterols, triterpenes, 7 fatty acids with olefinic and acetylenic bonds, 8 alkylfurans, 9 dimers of flavanols, 10 oligomeric proanthocyanidins 11 and glucosylated abscisic acids. 12 Persea pyrifolia is popularly known as maçaranduba and it is frequently employed in the furniture manufacturing industry. 13 The only study carried out on P. pyrifolia dealt with volatile compounds from the leaves. 14 As part of our on-going program devoted to phytochemical investigations on Brazilian Lauraceae species, in this work we report the isolation of an ester of the 4-O-E-caffeoylquinic acid (1) and three flavonoids (2-4) from O. corymbosa, an aromatic sesquiterpene (5) and a flavonoid (6) from O. elegans as well as four furofuran lignans (7-10) from P. pyrifolia. This is the first chemical study on the leaves of O. elegans and O. corymbosa as well as the first report of nonvolatile compounds from P. pyrifolia. EXPERIMENTAL GeneralAnalytical and preparative HPLC separations were performed by using stainless-steel Phenomenex Luna phenyl-hexyl (250 x 4.6 mm and 250 x 22 mm, 5 and 10 mm particle size, respectively) and Phenomenex Luna C-18 (250 x 4.6 mm and 250 x 22 mm, 5 and 10 mm particle size, respectively). Mobile phases for chromatography were prepared from HPLC grade solvents. Methanol and acetonitrile were obtained from J.T. Baker (Phillipsburg, NJ, USA) and Tedia (Fairfield, OH, USA), respectively. Water was purified in-house with a Millipore Milli-Q system (Billerica, MA, USA). The analytical HPLC separations were carried out using a Shimadzu (Kyoto, Japan) LC-10Ai pump system, a Shimadzu SIL-10Ai aut...

Phyllanthus niruri L., commonly known in Brazil as 'quebra-pedra', has long been used in the treatment of diverse diseases and especially urolithiasis. The therapeutic effects of P. niruri are attributed to various compounds present in the plant, including the hydrolysable tannin corilagin. In the present study, high-performance liquid chromatography (HPLC-/PAD) profiles of leaves and commercial extracts of P. niruri were examined and three compounds, found to be present in all of the samples studied, were isolated by open column chromatography over C18)silica gel followed by preparative HPLC. These compounds were identified by nuclear magnetic resonance as corilagin, rutin and ethyl 3,4,5-trihydroxybenzoate. Corilagin, which has been proposed as a phytochemical marker for P. niruri, was employed as an external standard in the development and validation of a rapid and efficient qualitative and quantitative HPLC assay for the analyte. The method may be applied in the standardization of herbs and phytomedicines commercialized in Brazil as quebra-pedra.

RESUMO: "Validação de método de cromatografia líquida de alta performance para padronização de extratos comerciais de Ptychopetalum olacoides Benth., Olacaceae". Ptychopetalum olacoides Benth., Olacaceae, popularmente conhecida como marapuama, muirapuama ou miriantã, é uma espécie nativa da região da Amazônia do Brasil. Extratos das cascas da planta são tradicionalmente usados por suas propriedades estimulantes e afrodisíacas, e frequentemente comercializados como constituinte de uma grande variedade de formulações fitoterápicas. O fracionamento por coluna cromatográfica aberta seguida por CLAE-UV/PAD das cascas do caule de três extratos comerciais de P. olacoides permitiram o isolamento de três substâncias comuns em todos os extratos analisados. Os compostos foram identificados por RMN como ácido vanílico, ácido protocatecuíco e teobromina. O ácido vanílico foi utilizado como marcador fitoquímico para P. olacoides e empregado como padrão externo no desenvolvimento e validação de um método de análise qualitativo e quantitativo rápido por CLAE. O valor da recuperação do método desenvolvido foi de 99,02% e os valores de LOD e LOQ foram 0,033 e 0,11 mg.L -1 , respectivamente. O método descrito poderá ser empregado para a padronização de plantas, extratos ou fitoterápicos comercializados como marapuama. Unitermos: CLAE-UV/PAD, RMN, Ptychopetalum olacoides, marapuama, ácido vanílico.ABSTRACT: Ptychopetalum olacoides Benth., Olacaceae, popularly known as marapuama or muirapuama or miriantã, is a species native to the Amazonian region of Brazil. Extracts of the bark of the plant have been used traditionally for its stimulating and aphrodisiac properties and currently commercialised by the herbal industry as constituents in a wide range of phytomedicines. Fractionation by open column chromatography followed by preparative HPLC-UV/PAD of the stem bark and of three commercial extracts of P. olacoides allowed the isolation of three components that were common to all extracts analysed, and these were identified by NMR to be vanillic acid, protocatechuic acid and theobromine. Vanillic acid, which has been proposed as a phytochemical marker for P. olacoides, was employed as an external standard in the development and validation of a rapid qualitative and quantitative HPLC assay for the analyte. The recovery values of the developed method were 99.02% and the LOD and LOQ values were 0.033 and 0.11 mg.L-1, respectively. The described method may be applied to the standardization of herbs, extracts or phytomedicines commercialised as marapuama.

Myrcia uniflora Barb. Rodr., Myrtaceae, popularly known as "pedra-humecaá" in Brazil, is sold as dry extracts in capsules or as tinctures for the treatment of diabetes mellitus. Previous phytochemical studies on this species described the occurrence of the flavonoids mearnsitrin and myricitrin. In the present study, the chromatographic profiles of M. uniflora leaves and commercial extracts were determined using HPLC-PAD. Myricitrin was used as an external standard in the development and validation of the HPLC method. The proposed method is simple, rapid and reliable and can be successfully applied in industry for standardization of herbs and phytomedicines commercialised in Brazil as "pedra-hume-caá".

Vibrational circular dichroism (VCD) is one of the most powerful techniques to assess stereochemistry of chiral molecules in solution state. The need for quantum chemical calculations to interpret experimental data,...