Biochemical Systematics and Ecology 35 (2007) 456e458 www.elsevier.com/locate/biochemsyseco Alkaloids and a new cinnamate derivative from Duguetia gardneriana Jackson Roberto Guedes da Silva Almeida a,b, Ana Sı́lvia Suassuna Carneiro Lúcio b, José Maria Barbosa-Filho b, Maria de Fátima Agra b, Marcelo Sobral da Silva b, Emidio Vasconcelos L. da Cunha b,c,*, Daniel Esdras de Andrade Uchoa d, Raimundo Braz-Filho e a b Universidade Federal do Vale do S~ao Francisco, Cx. Postal 252, 56306-410 Petrolina, PE, Brazil Laboratório de Tecnologia Farmacêutica, Universidade Federal da Paraı́ba, Cx. Postal 5009, 58051-970 Jo~ao Pessoa, PB, Brazil c Departamento de Farmácia, Universidade Estadual da Paraı́ba, 58100-000 Campina Grande, PB, Brazil d Departamento de Quı́mica Orgânica e Inorgânica, Universidade Federal do Ceará, Fortaleza, CE, Brazil e Setor de Quı́mica de Produtos Naturais, Universidade Estadual Norte Fluminense, 28015-620 Campos, RJ, Brazil Received 6 December 2006; accepted 8 December 2006 Keywords: Duguetia gardneriana; Annonaceae; Alkaloids; Phenylpropanoid 1. Subject and source The Annonaceae is a large family comprising ca. 130 genera and 2300 species. Phytogeographically it is entirely tropical, with 39 genera being represented in tropical America. This plant family is recognized as being the center for isoquinoline alkaloids production in plants (Goulart et al., 1986). Duguetia gardneriana Mart. (Annonaceae) was collected in January 2004 near the city of Santa Rita, State of Paraı́ba, Brazil, and identified by the specialist Maria de Fatima Agra. A voucher specimen (AGRA 1814) is deposited at the Herbarium Lauro Pires Xavier (JPB), Universidade Federal da Paraı́ba. 2. Previous work The genus Duguetia consists of approximately 70 species, of which 50 are found in Brazil (Hutchinson, 1964). Species are predominantly found in the tropical Americas, mainly the Amazon basin and the Guianas, however, some species can be found in the southern region of South America (Muhammad et al., 2001; Carollo et al., 2005). * Corresponding author. Laboratório de Tecnologia Farmacêutica, Universidade Federal da Paraı́ba, Cx. Postal 5009, 58051-970 Jo~ao Pessoa, PB, Brazil. Tel.: þ55 83 32167361; fax: þ55 83 32167364. E-mail address: emidio@ltf.ufpb.br (E.V.L. da Cunha). 0305-1978/$ - see front matter Ó 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.bse.2006.12.011 J.R.G. da Silva Almeida et al. / Biochemical Systematics and Ecology 35 (2007) 456e458 457 In our continuing search for new biologically-active compounds from this genus we have previously isolated alkaloids and volatile constituents from Duguetia flagellaris (Fechine et al., 2002a) and Duguetia trunciflora (Fechine et al., 2002b). There is no previous report on the analysis of the chemical constituents of D. gardneriana. 3. Present study Three alkaloids and a new cinnamate derivative were isolated from the ethanol extract of the stem-barks of D. gardneriana. The dried and powdered stem-barks (3 kg) were repeatedly extracted with 95% EtOH at room temperature. The ethanol extract was concentrated under vacuum. The alkaloids and cinnamate obtained were isolated with the use of a series of partitions involving acid/base separation. The procedure was as follows: the crude EtOH extract was stirred in a solution of 3% HCl and filtered over celite, the precipitate was treated with ethyl ether. The ether extract containing the non-basic substances was designated Fraction A. The acidic solution was made alkaline with NH4OH to pH 9 and extracted with CHCl3. The residue of this CHCl3 extract containing the basic substances was called Fraction B. Chromatography of the non-alkaloidal portion (Fraction A) on CC Si gel (gradient elution) followed by successive chromatographic PTLC yielded an new cinnamate derivative methyl 3,5-dihydroxy-4-ethoxycinnamate; this substance is described here for the first time. The cinnamate is an amorphous solid. 1H NMR (CDCl3, 200 MHz) d 7.57 1H d J ¼ 16 Hz (H-7); 6.75 2H s (H-2/H-6); 6.28 1H d J ¼ 16 Hz (H-8); 4.24 2H q J ¼ 7 Hz (H-100 ); 3.89 3H s (10 OMe); 1.31 3H t J ¼ 7 Hz (H-200 ). 13C NMR (CDCl3, 50 MHz) d 167.13 (C-9); 147.13 (C-3/C-5); 144.82 (C-7); 136.97 (C-4); 125.87 (C-1); 115.96 (C-8); 104.91 (C-2/C-6); 60.36 (C-100 ); 56.26 (10 -OMe); 14.31 (C-200 ). A combination of column chromatography on alumina and PTLC Si gel of the alkaloidal portion (Fraction B) yielded pure discretamine, tetrahydrojathrorrizine and tetrahydropalmatine (Fechine et al., 2002b). The compounds were identified by spectroscopic methods such as NMR 1H and 13C (1D and 2D experiments). O 7 2 HO 3 1' OCH3 1 8 2" 1" CH3-CH2O 4 6 5 OH Methyl 3,5-dihydroxy-4-ethoxycinnamate 4. Chemotaxonomic significance This is the first report of the isolation of methyl 3,5-dihydroxy-4-ethoxycinnamate in the literature and the first of the isolation of a cinnamate from a plant of the genus Duguetia. Although tetrahydroprotoberberine alkaloids are commonly found in the Annonaceae (Leboeuf et al., 1982), including some species of the genus Duguetia, no reports were found on phytochemical studies with D. gardneriana. The results obtained in this study confirm that plants of this genus have a strong ability to produce protoberberine alkaloids, a class of compounds typically found in plants of the Annonaceae. The alkaloids isolated here have been isolated from other species in the family Annonaceae and could be considered as chemotaxonomic markers. Acknowledgements This work was supported by grants from CNPq and CAPES. The authors wish to express their thanks to the College of Pharmacy of the University of Illinois, Chicago, USA, for granting access to the NAPRALERT database. 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