Foram isoladas de extratos de folhas de Ocotea catharinensis Mez (Lauraceae) quatorze neolignanas sendo nove benzofurânicas (incluindo três novas substâncias 1e, 2f e 4b), uma secobenzofurânica inédita (3b), duas biciclo[3.2.1]octânicas (incluindo a nova 5c), dois novos dímeros biciclo[3.2.1]octânicos (7a e 7b) e ainda dois sesquiterpenos (incluindo o novo humulanol 9). Nos embriões somáticos de O. catharinensis foram identificadas sete neolignanas incluindo uma nova neolignana biciclo[3.2.1]octânica (4a).The extracts from leaves of Ocotea catharinensis Mez (Lauraceae) were found to contain fourteen neolignans and two sesquiterpenes: nine benzofuran types (including three new compounds 1e, 2f and 4b), one new seco-benzofuran type (3b), two bicyclo[3.2.1]octane types (including the new compound 5c), two new dimers of bicyclo[3.2.1]octane type (7a and 7b) and two sesquiterpenes (including a new humulanol 9). In addition, seven neolignans were also showed to occur in somatic embryos of O. catharinensis including one new bicyclo[3.2.1]octane type (4a).
Keywords:Ocotea catharinensis, benzofuran neolignans, bicyclo[3.2.1]octane neolignans, humulane sesquiterpene, somatic embryos
IntroductionOcotea catharinensis (Lauraceae) is a woody plant species found in southern Atlantic forest in Brazil, which produces excellent quality of timber. The extensive logging over the past thirty years associated with difficulties for propagation has led its natural population to be significant decrease. Since O. catharinensis has been included as endangered species, a somatic embryogenic system was developed aiming to a massive propagation.
1,2The Ocotea has been one of the most phytochemically investigated Lauraceous genus and their major secondary compounds were showed to be phenylpropanoidderived including several sub-classes of neolignans.
3Previous phytochemical studies carried out in leaves of O. catharinensis collected at Horto Florestal (Serra da Cantareira), São Paulo State, Brazil, reported the occurrence of benzofuran (1b, 1c, 1d, 2b, 2c, 2d, 2e and 2h) and bicyclo[3.2.1]octane (5a, 5b and 5d) neolignans.
4Representatives of both sub-classes of neolignans have also been previously isolated from barks and woods of a specimen collected in São Paulo State, 5,6 and also from wood and leaves of O. porosa ("imbuia") collected in Rio Grande do Sul State, southern Brazil. [7][8][9] This work describes the isolation and characterization of major secondary compounds from leaves collected at Vale do Itajaí, Santa Catarina State, Brazil and from embryogenic cultures developed from the same plant source. The extracts from leaves afforded seven new neolignans 1e, 2f, 3b, 4b, 5c, 7a, 7b, besides seven previously reported ones 1a, 6,10
Results and DiscussionThe defatted fraction of hexane extracts from O. catharinensis leaves and from O. catharinensis somatic embryos were submitted to flash chromatography followed by prep. TLC and/or circular chromatography (Chromatotron®). This procedure yielded nine new compounds (1e, 2f, 3b, 4a, 4b, 5c, ...
