Estudo químico de plantas amazônicas: Eugenia biflora, Myrcia citrifolia, Licaria puchury-major, Licaria macrophylla e Licaria aurea

Abstract

From the leaves of a specimen of Eugenia biflora (L.) DC. and another of Myrcia citrifolia (Aubl.) Urb., from the Val-de-Cão woods in Belém do Pará and the Manaus-Itacoatiara roadside, km 27, Manaus, Amazonas, respectively, b-amirine and eucalyptine were isolated (5-hydroxy-4 ', 7-dimethoxy-6,8-dimethylflavone). From a specimen of Licaria puchury-major (Mart.) Kosterman, grown at km 14 of the Manaus-Itacoatiara road, in Manaus, Amazonas, a large branch was obtained. In addition to sitosterol, eugenol, safrole, 3,4-methylenedioxycinamic aldehyde and siringenic aldehyde (4-hydroxy-3,5-dimethobenzaldehyde), an unprecedented substance as a natural product, 3,4-methylenedioxycinaminic alcohol was isolated from its wood. The structures of these substances were determined by the application of physical methods (spectrometric) and preparation derived therefrom. The synthesis of 3,4-methylenedioxycinnamyl alcohol was carried out by allyl bromination of isosafrole and hydrolysis of the crude reaction product. From a specimen of Licaria macrophylla (AC Smith) Kosterman, collected at the Ducke Forest Reserve of the National Research Institute of the Amazon, in Manaus Amazonas, a new substance, macrophylline, was isolated, in addition to sitosterol and two unidentified sesquiterpene alcohols (1 -alyl-8-hydroxy-3,5-dimethoxy-7-methyl-4-oxo-6- (3 ', 4'-methylenedioxy-5'-methoxyphenyl) -bicycle [3,2,1] oct-2- eno), belonging to a nine class of organic compounds, called neolignans. From a specimen of Licaria aurea (Huber) Kosterman, collected in the Ducke Forest Reserve of the National Research Institute of the Amazon, in Manaus Amazonas, two neolignans, aurein (containing the functional groups represented in Table 3) and eusiderin (2- ( 3 ', 4', 5'-trimethoxyphenyl) -3-methyl-7-allyl-9-methoxybenzodioxane), the latter previously isolated from another species of lauracea, Eusideroxylon zwageri T. et B., which occurs in Indonesia. Very few neolignans are known. Most of them were obtained by researchers from our group. For explaining its biosynthesis, it becomes necessary to postulate paths that constitute variants of the accepted paths for the formation of lignans. One of these variants is adopted in order to rationalize the macrophylline biogenesis in nature.