PHYTOCHEMICAL ANALYSIS 322Phytochem. Anal. 16, 322–327 (2005) R. SUAU ET AL. Published online 9 August 2005 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002.pca.851 Identification and Quantification of Isoquinoline Alkaloids in the Genus Sarcocapnos by GC-MS R. Suau,1* B. Cabezudo,2 M. Valpuesta,1 N. Posadas,1 A. Diaz1 and G. Torres1 1Departamento de Química Orgánica, Universidad de Málaga, E-29071 Málaga, Spain 2Departamento de Biología Vegetal, Universidad de Málaga, E-29071 Málaga, Spain Six cularine alkaloids, cularicine, O-methylcularicine, celtisine, cularidine, cularine and celtine, three isocularine alkaloids, sarcophylline, sarcocapnine and sarcocapnidine, and five non-cularine alkaloids, glaucine, protopine, ribasine, dihydrosanguinarine and chelidonine, were identified and quantified by GC-MS in nine taxa of the genus Sarcocapnos (Fumariaceae). The chemotaxonomic significance of the results is discussed. Copyright © 2005 John Wiley & Sons, Ltd. Keywords: Gas chromatography–mass spectrometry; isoquinoline alkaloids; chemotaxonomy; Sarcocapnos; Fumariaceae. derived alkaloids, such as aporphines, protopines, proto- INTRODUCTION berberines and benzophenanthridines, found widely in the Papaveraceae and Fumariaceae, are also present in The genera Fumaria, Corydalis, Rupicapnos, Platy- species of Sarcocapnos (Preininger, 1986). The reduced capnos, Ceratocapnos and Sarcocapnos, belonging to the forms of cularine and isocularine alkaloids are highly family Fumariaceae, are widely distributed in Europe active at dopaminergic receptor sites (Protais et al., and Northern Africa. Various types of isoquinoline 1995), and they have also been tested as smooth muscle alkaloids have been isolated from this family (Suau et al., relaxants (D’Ocón et al., 1991). In contrast, the oxidized 1991, 2002a; Valpuesta et al., 1995), a characteristic that forms (3,4-dioxocularines and aristocularines) exhibit has been used for their chemotaxonomic evaluation significant cytotoxic activity (Suau et al., 2002b). Studies (Preininger, 1986). on species of Sarcocapnos have so far involved conven- The genus Sarcocapnos comprises nine taxa found in tional phytochemical methodologies (extraction, separa- the western Mediterranean area (Spain, France, Mo- tion and structure determination) and have focussed on rocco and Algeria) with a centre of variation in southern identifying the major and minor components (López Spain (Lidén, 1986a,b; Lidén et al., 1997, Fukuhara, et al., 1991). In a number of cases a large amount of plant 1999). The taxonomy and phylogeny of the genus have material was available for study, whilst in others only recently been described (Salinas et al., 2003). Typically, small samples were used owing to the danger of extinc- populations of Sarcocapnos species consist of only a few, tion of the species concerned or difficulties in collection. mutually distant, individuals: as a result, they exhibit con- For this reason the alkaloidal content of many species siderable genetic isolation, and are difficult to character- has not been determined very accurately. ise morphologically (Salinas and Suárez-Santiago, 2002). In the present work, GC-MS was used to study the Phytochemical studies (López et al., 1991) on five tertiary isoquinoline alkaloid composition of members species, namely Sarcocapnos enneaphylla (L.) DC, S. of the genus Sarcocapnos, including S. pulcherrima saetabensis (Mateo and Figuerola, 1987), S. integrifolia (Morales and Romero, 1991), S. baetica subsp. ardalii (Boiss.) Cuatrec., S. baetica subsp. baetica (Boiss. and (López-Vélez, 1991), S. crassifolia subsp. crassifolia Reut.) Nyman and S. speciosa Boiss., have shown them (Desf.) DC. and S. crassifolia subsp. atlantis (Emb. and to be excellent sources of an unusual class of isoquinoline Maire) (Lidén, 1986b) that have been investigated for alkaloids, namely, the cularinoids (Castedo and Suau, the first time. GC-MS has proven to be a fast and reliable 1986). Biosynthetically, these alkaloids are related to methodology that is an effective tool for the systematic crassifoline, a 1-benzylisoquinoline with an atypical 7,8- evaluation of the Sarcocapnos, a genus that presents a substitution pattern at the isoquinoline nucleus (Müller number of difficulties of a morphological and molecular and Zenk, 1993). Reduced forms of cularinoids, cularines nature (Salinas et al., 2003). and isocularines (with 3′,4′- and 4′,5′-substitution patterns, respectively) are the major alkaloids in Sarcocapnos species (Fig. 1). However, cularinoids with various degrees of oxidation (i.e. 4-hydroxy cularines, EXPERIMENTAL oxocularines, 3,4-dioxocularines and aristocularines), cularinoids exhibiting different skeletal modifications Plant material. Aerial parts of species of Sarcocapnos (N-seco- and C-seco-cularines) and quaternary cularines were obtained from their natural habitats. Voucher occur as minor components. In addition, reticuline- specimens of the investigated plants (Table 1) were deposited in the Faculty Herbarium (MGC) of the * Correspondence to: R. Suau, Departamento de Química Orgánica, Universidad Department of Botany of the University of Malaga de Málaga, E-29071 Málaga, Spain. Email: [email protected] (Spain) and the herbarium (RAB) of the University of Contract/grant sponsor: Spanish DGI; Contract/grant number: BQU2001-1890. Rabat (Morocco). Copyright © 2005 John Wiley & Sons, Ltd. Phytochem. AnalReceived. 16: 322–327 28 April (2005) 2004 Copyright © 2005 John Wiley & Sons, Ltd. Revised 25 October 2004 Accepted 5 November 2004 GC-MS ANALYSIS OF ISOQUINOLINE ALKALOIDS 323 Figure 1. Isoquinoline alkaloids identified and quantified in this study. Extraction of alkaloids. Air-dried samples (10–20 g) of 25 mL). The resulting extracts were dried with magne- aerial parts, randomly collected from several individuals sium sulphate and the solvent evaporated to obtain the of each population, were powdered and exhaustively crude tertiary alkaloid extract. The aqueous phase gave extracted with methanol (150 mL) in a Soxhlet apparatus a negative or extremely weak Mayer’s test, consistent until Mayer’s test proved negative. The solvent was with the absence of quaternary cularines or their pres- evaporated, the residue taken up in 2.5% hydrochloric ence at very low concentrations. acid (60 mL), and insoluble components removed by filtration. The filtrate was adjusted to pH 8 with aqueous GC-MS analysis. Analyses were carried out on a ammonia and extracted with dichloromethane (4 × Hewlett Packard (HP; Palo Alto, CA, USA) model HP Table 1. Voucher specimen numbers and collection locations of the studied species Sarcocapnos species Voucher specimen number Location of collection S. enneaphylla (type I) MGC 35666 Nerja (Malaga, Spain) S. enneaphylla (type II) MGC 35660 Otivar (Granada, Spain) S. enneaphylla (type III) MGC 35142 Buitrago (Madrid, Spain) S. enneaphylla (type III) MGC 36001 Teruel (Spain) S. saetabensis (type I) MGC 31042 Benissa (Alicante, Spain) S. saetabensis (type II) MGC 36003 Xátiva (Valencia, Spain) S. baetica subsp. baetica MGC 25938 Carratraca (Malaga, Spain) S. baetica subsp. ardalii MGC 51000 Yeste (Albacete, Spain) S. integrifolia MGC 31775 Noalejo (Jaen, Spain) S. pulcherrima MGC 31776 Jatar (Granada, Spain) S. speciosa MGC 31774 Lacalahorra (Granada, Spain) S. crassifolia subsp. crassifolia MGC 35114 Ifrane (Morocco) S. crassifolia subsp. atlantisa RAB 10936 Amezgane (Morocco) a Herbarium sample. Copyright © 2005 John Wiley & Sons, Ltd. Phytochem. Anal. 16: 322–327 (2005) 324 R. SUAU ET AL. Table 2. Alkaloids identified by GC-MS in members of the genus Sarcocapnos Retention time,a [M+] and characteristic ions, m/z Alkaloid min (% relative intensity) Alkaloid type Sarcophylline 6.24 327 (100), 312 (65), 294 (53) Isocularine Sarcocapnine 6.45 341 (100), 326 (60), 176 (90) Isocularine Cularicine 6.61 311 (100), 294 (90), 161(40) Cularine O-Methyl-cularicine 6.84 325 (100), 308 (60), 174 (40) Cularine Cularidine 7.22 327 (40), 312 (100) Cularine Celtisine 7.27 313 (58), 298 (100) Cularine Cularine 7.47 341 (34), 326 (100) Cularine Sarcocapnidine 7.51 327 (100), 312 (30), 310 (30) Isocularine Celtine 7.63 327 (39), 312 (100) Cularine Glaucine 8.04 355 (90), 354 (100), 340 (80) Aporphine Protopine 8.78 353 (5), 148 (100) Protopine Ribasine 9.49 351 (90), 350 (100) Indanobenzazepine Dihydrosanguinarine 10.91 333 (90), 332 (100) Benzophenanthridine Chelidonine 11.67 353 (20), 335 (80), 304 (100) Benzophenanthridine a For GC conditions see the Experimental section. 5988A mass spectrometer coupled to an HP 5980 gas cularine (M+, 341, 34%) occurred at m/z 326 and corre- chromatograph equipped with an HP-1 fused silica cap- sponded to the loss of the methyl group at position 3′. illary column (12 m × 0.2 mm i.d.; 0.33 mm film thick- For the mono-phenolic isocularine sarcocapnidine, which ness). Helium, at a flow-rate of 1 mL/min, was used as has no methyl group at 3′, the molecular ion occurred the carrier gas. The column temperature was held ini- at m/z 327 as the base peak. Thus, the 326:327 peak ratio tially at 200°C for 4 min, increased to 250°C at 10°C/min provided an effective estimate of the relative abundance and then held at 250°C for 15 min. The ion source of the of both alkaloids. The relative intensities of the signals mass spectrometer was operated at 250°C and the trans- at m/z 341 and 311, corresponding to the molecular fer line was maintained at 280°C. Electron impact ion- ions (100%) of sarcocapnine and cularicine, respectively, isation was carried out at an energy of