Constituintes químicos isolados de Schwartzia brasiliensis (Choisy) Bedell ex Gir.-Cañas

Abstract

Schwartzia brasiliensis Choisy belongs to the Marcgraviaceae family, and has wide occurrence from the northeast to the south of Brazil, it is popularly known as "rabo-de-arara", "chinelo-de-anjo", "pente-de-macaco" and "agarrapé". Its leaves are used by the northeastern population in the preparation of teas and bottles for the treatment of heart diseases. Phytochemical studies with this species already reported some pharmacological potentials, but there are few evidences of chemical knowledge. Thus, this work aims to contribute to the expansion of chemical knowledge of this species. The plant material was collected in May 2017 in the city of Puxinanã - PB and identified by the botanist Dr. José Iranildo Miranda de Melo, an exsicata has been catalogued in the Arruda Câmara Herbarium (HACAM - UEPB), under the code 1268, with access registration in the National System for the Management of Genetic Heritage and Associated Traditional Knowledge (SISGEN) under the code A021E1B. The aerial parts of Schwartzia brasiliensis were dried in an oven at 40 ºC, crushed and extracted with 95% ethanol, and concentrated in a rotaevaporator obtaining the Crude Ethanolic Extract (CEE), then submitted to liquid/liquid partition obtaining the hexanic, dichloromethane and ethyl acetate phases. An aliquot of the hexanic phase was submitted to a column chromatography with silica gel, resulting in 13 fractions from where the triterpenic mixture of α-amyrin and β-amyrin was isolated and also the identification of some hydrocarbons presents in this phase analyzed and identified by GC/MS was performed. An aliquot of the dichloromethane phase was submitted to Medium Pressure Liquid Chromatography from where 7-hydroxycoumarin was isolated. An aliquot of ethyl acetate phase was also used and submitted to column chromatography using sephadex LH-20 and from this saponin named as schwartenozide isolated for the first time in the literature was isolated. The substances were identified by 1H and 13C NMR spectroscopy and two-dimensional, and compared with the literature. In addition, a specific methodology of saponin extraction with CEE was performed, which made possible the proposals for identification of four triterpenic bidesmosidic saponins using HPLC-ESI-DAD-MS/MS. Finally, this work contributed to the expansion of the phytochemical knowledge of Schwartzia brasiliensis, through the isolation of compounds reported for the first time in this species, evidencing the first report of saponins in the Marcgraviaceae family, as well as giving directions for future studies.