Janete H. Y. Vilegas

Extraction of low-polarity compounds (with emphasis on coumarin and kaurenoic acid) fromMikania glomerata (‘guaco’) leaves

Five methods for the extraction of low-polarity compounds from Mikania glomerata Spreng. (Compositae) leaves were compared: conventional maceration, maceration with sonication, Soxhlet, and supercritical fluid extraction using hexane (SFE-hexane) or carbon dioxide (SFE-CO2) as the extraction fluid. Evaluation of these methods by relating extraction yield to extraction time showed that SFE-hexane was the most efficient method. SFE-CO2 showed a lower yield, but significantly higher than conventional methods (maceration and Soxhlet). SFE-hexane and maceration gave the highest yield of coumarin, while maceration under sonication gave the highest yield of kaurenoic acid. Among the further chemical constituents of Mikania glomerata leaves identified by high resolution gas chromatography–mass spectrometry were lupeol and lupeol acetate.

Further triterpenes, steroids and furocoumarins from brazilian medicinal plants of dorstenia genus (moraceae)

The hexane-soluble fractions from the rhizomes or from the leaves from five Dorstenia (Moraceae) species (D. bahiensis Kl., D. bryoniifolia Mart ex. Miq., D. carautae C.C.Berg, D. cayapiaa Vell. and D. heringerii Car. & Val) were analysed by HRGC-MS (high-resolution gas chromatography - mass spectrometry). Pentacyclic triterpenes, steroids and furocoumarins were identified. HRGC-MS is shown to be a valuable tool for the analysis of terpenoidal compounds from Dostenia species. These compounds may be related to the folk utilization of Dorstenia species as antiophidicals.

Supercritical fluid extraction of glycosylated flavonoids fromPassiflora leaves

This work describes the extraction of glycosylated flavonoids from ‘passion fruit’ leaves (Passiflora edulis; Passifloraceae), using carbon dioxide in the supercritical state modified with chloroform, ethyl acetate or short-chain alcohols. Carbon dioxide modified with 10% methanol was shown to be the best extraction fluid, considering both the yield of the flavonoid extracts and the temperature conditions. The supercritical fluid extracts were compared to those obtained by using a conventional extraction method for Passiflora flavanoids, indicating the advantages of supercritical fluid extraction as an alternative method for the analysis of flavonoids from other ‘passion fruit’ species (P. alata and P. incarnata).

Application of on-line C30 RP-HPLC-NMR for the analysis of flavonoids from leaf extract of Maytenus aquifolium.

Universidade Estadual Paulista Instituto de Quimica de Araraquara, CP 355, 14801-970, Araraquara, SP

Comparison of extraction and clean-up methods for the analysis of friedelan-3-ol and friedelin from leaves of Maytenus aquifolium Martius (Celastraceae).

A comparative study of three extraction methods (maceration/sonication, Soxhlet and supercritical fluid extraction) and three clean-up procedures for chromatographic analysis (high resolution gas chromatography with flame ionisation detection; HRGC-FID) of the triterpenes friedelan-3-ol and friedelin from leaves of Maytenus aquifolium Martius (Celastraceae), one of the species known in Brazil as “espinheira santa”, has been conducted. Supercritical fluid extraction utilising carbon dioxide modified with ethanol was shown to be the most effective extraction method, while clean-up utilising Florisil® as adsorbent was the most appropriate for further HRGC-FID quantitative analysis of the extracts. Copyright

A 1H and 13C NMR study of a novel naturally occurring furocoumarin from Dorstenia cayapiaa

Abstract The chemical structure of a naturally occurring furocoumarin from Dorstenia cayapiaa ( 1 ) has been established by 1D and 2D NMR methods.

Aporphine alkaloids from Ocotea caesia

Abstract The trunk-wood of Ocotea caesia contains the aporphine alkaloids (−)-zenkerine, (+)-laurelliptine, (−)-pulchine and (+)-isoboldine and the novel alkaloid ( S )-(+)-1-hydroxy-2,9-dimethoxynoraporphine.

Composition of the volatile compounds from Aniba canelilla (H. B. K.) Mez. extracted by CO2 in the supercritical state

The volatile compounds obtained by SFE-CO2 (supercritical fluid extraction utilizing CO2) from the barks of Aniba canelilla (H. B. K.) Mez. (Lauraceae) were analyzed by HRGC-FID (high resolution gas chromatography - flame ionization detector) and HRGC-MS (high resolution gas chromatography -mass spectrometry). Phenylpropanoids and lower amounts of sesquiterpenoids, representing ca. 97% of the total oil, were identified. The main compound, 2-phenylnitroethane, corresponds to 71,12% of the total oil.

A cinnamoylglucose from Gomortega keule

Abstract Examination of bark and trunk wood of Gomortega keule resulted in the isolation of 1,3,6-tri- O - p -methoxycinnamoyl-β- d -glucose.

Chromatographic and spectroscopic analysis of resins extracted from coal with ethanol in the supercritical state

Abstract The study of coal as an alternative energy source and as a feedstock is of great importance due to the uncertainty of petroleum production and the certainty that this source will someday be exhausted. In this work, supercritical ethanol was used to extract the organic material from a southern Brazilian coal. The chemical characterization of this product was carried out using chromatographic and spectroscopic methods in order to obtain a profile of the main components. Important classes of compounds observed, such as phenols and heterocyclic compounds, among others, suggests the need for a better way to use the studied coal.