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Leontidine-type quinolizidine alkaloids in Orphanodendron (Leguminosae)
Biochemical Systematics and Ecology 73 (2017) 47e49
Contents lists available at ScienceDirect
Biochemical Systematics and Ecology journal homepage: www.elsevier.com/locate/biochemsyseco
Leontidine-type quinolizidine alkaloids in Orphanodendron (Leguminosae) Geoffrey C. Kite Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AB, UK
a r t i c l e i n f o
a b s t r a c t
Article history: Received 3 February 2017 Received in revised form 2 June 2017 Accepted 3 June 2017
Herbarium leaf fragments of the two known species of Orphanodendron (Leguminosae), O. bernalii and O. grandiflorum, were found to contain the quinolizidine alkaloids camoensine (1), camoensidine (2) and guianodendrine (3), supporting the recent phylogenetic placement of the genus in the genistoid clade of subfamily Papilionoideae rather than its traditional placement in subfamily Caesalpinioideae. © 2017 Elsevier Ltd. All rights reserved.
Keywords: Orphanodendron Quinolizidine alkaloids Camoensine Camoensidine Guianodendrine
1. Subject and source The legume genus Orphanodendron was erected in 1990 by Barneby and Grimes to accommodate O. bernalii Barneby & Grimes, a newly-described tree species from Columbia (Barneby and Grimes, 1990). Barneby and Grimes (1990) placed Orphanodendron, with some reservations, in subfamily Caesalpinioideae (sensu Polhill and Vidal, 1981) e their chosen genus name reflected their uncertainty about its subfamilial relationships. Recently, a second species, O. grandiflorum Cast. & G.P.Lewis, has been described, also from Columbia (Castellanos et al., 2015). The current report examines leaves of both species of Orphanodendron for the presence of quinolizidine alkaloids. This work was undertaken in response to recent phylogenetic analyses of DNA sequence data that placed Orphanodendron in the genistoid clade of subfamily Papilionoideae (Castellanos et al., 2017). 2. Previous work There have been no previously published chemical analyses of Orphanodendron. The present work was referred to by Castellanos et al. (2017). 3. Present study Leaf fragments of Orphanodendron and, for chemical comparison, Camoensia scandens (Welw.) J.B. Gillett and Guianodendron http://dx.doi.org/10.1016/j.bse.2017.06.002 0305-1978/© 2017 Elsevier Ltd. All rights reserved.
praeclarum (Sandwith) R. Schütz & A.M.G. Azevedo, were obtained from herbarium sheets and associated silica gel collections lodged at the Royal Botanic Gardens, Kew (K) (Table 1). Leaf fragments (c. 50 mg) were weighed exactly, powdered in a pestle and mortar and extracted in 1 ml CH3OH for 2 h. Plant residue was removed by centrifugation and the extract was dried into an Eppendorf tube under a stream of nitrogen gas. Extracted compounds were vortexed in 1 ml CHCl2/2M CH3COOH (1:1) followed by centrifugation to separate the phases. The CHCl2 layer was removed and the aqueous layer was made alkaline (pH 12) by addition of aq. ammonia. An equal volume of CHCl2 was added and following vortexing and centrifugation, the CHCl2 layer was removed and dried under nitrogen. The sample was dissolved in CH3OH (100 ml per 50 mg leaf extracted) for analysis by GC-MS using an Agilent 5975C system fitted with a 30 m 0.25 mm i.d. 0.25 mm DB-1MS column (J&W). Chromatography of split (1:10) 1 ml injections was effected using 1 ml/min He flow and a temperature gradient of 120e320 C at 5 C/min, holding at the upper temperature for 10 min. The MS was set to record standard 70eV EIMS in the range m/z 50e650. GC-MS analyses revealed quinolizidine alkaloids in all the specimens of Orphanodendron studied, although levels were relatively lower in the specimens of O. grandiflorum except the type (23504), which contained levels similar to O. bernalii (Fig. 1; Table 2). The most abundant alkaloid in several of the samples of both species had the same retention index (RI ¼ 2332), molecular mass (230 Da) and EIMS as the major alkaloid in the analysis of
48
G.C. Kite / Biochemical Systematics and Ecology 73 (2017) 47e49
Table 1 List of samples analysed. No.
Species
Collection Reference
Collection locality and date
Drying
23518
Camoensia scandens
Cultivated. Herb. Hort. Kew (K)
Air
22770
Guianodendron praeclarum
23505
Orphanodendron bernalii
Forest Dept. of Guyana field no. A69 (record no. 2353) (holotype, K), Callejas et a. 5802 (K)
23506
O. bernalii
Castellanos 703 (K)
Cult, RBG Kew, –/02/1930 Makauria, Guyana, 01/03/1934 , Columbia, Mutata 22/11/1987 , Columbia, Mutata 22/03/2012
23507 23508
O. bernalii O. bernalii
Castellanos 703 (K) Castellanos 701 (K)
00
Silica Air
23509 23512
O. bernalii O. bernalii
Castellanos 701 (K) Cogollo et al. 12796 (K)
23513 23503
O. bernalii O. grandiflorum
Cogollo et al. 12796 (K) Castellanos & Marino 451 (K)
23504
O. grandiflorum
Castellanos & Marino 600 (type, K)
23510
O. grandiflorum
Castellanos & Cepeda 750 (K)
23511
O. grandiflorum
Castellanos & Cepeda 750 (K)
Camoensia scandens and was assigned as camoensine (1), this alkaloid having been first described as the major alkaloid in C. scandens (as C. maxima Welw. ex Benth.; Santamaria and Khuong-Huu, 1975). Also present in several samples was an alkaloid (RI ¼ 2102; M ¼ 234 Da) with analytical data matching another alkaloid in C. scandens. This was assigned as camoensidine (2) the EIMS of this alkaloid matched that shown for 2 by Kinghorn and Balandrin (1984). Another alkaloid (RI ¼ 2184; M ¼ 232 Da) present in both species showed identical analytical data to guianodendrine (3) isolated from Guianodendron praeclarum (Kite et al., 2013). Two unassigned alkaloids were also detected: 4
, Columbia, Mutata 21/03/2012 00
, Columbia, Mutata 23/02/2013 00
Landazuri, Columbia, 02/08/2008 Bolívar, Columbia, 01/05/2009 Bolívar, Columbia, 02/03/2010 00
Air Air Air
Silica Air Silica Air Air Air Silica
(RI ¼ 2136) had the same molecular mass (234 Da) as 2 and a similar EIMS and 5 (RI ¼ 2174) had a molecular mass of 230 Da. Anagyrine (6, RI ¼ 2426) was detected as a minor alkaloid in some samples and was assigned against published data (Wink, 1993). 4. Chemotaxonomic significance Within Leguminosae, quinolizidine alkaloids are only known from members of the early-branching genistoid s.l. clade (sensu Cardoso et al., 2012a) of subfamily Papilionoideae (Kite et al., 2003). The presence of quinolizidine alkaloids in Orphanodendron
Fig. 1. Total ion chromatograms (left) from GCMS analyses of O. grandiflorum (23504), O. bernalii (23509), C. scandens (23518) and G. praeclarum (22770) with EIMS of camoensine (1), camoensidine (2) and guianodendrine (3) from these analyses. Structures are those given by Kubo et al. (1994) (1, 2) and Kite et al. (2013) (3).
G.C. Kite / Biochemical Systematics and Ecology 73 (2017) 47e49
Table 2 Relative amounts (% peak area in total ion GCMS chromatograms) of quinolizidine alkaloids (QAs) in samples studied. Tot. ¼ total absolute peak areas (arbitrary units). Only peaks assigned as QAs measured. Sample No
Species
1
2
3
4
5
6
Tot.
23518 22770 23505 23506 23507 23508 23509 23512 23513 23503 23504 23510 23511
Camoensia scandens Guianodendron praeclarum Orphanodendron bernalii O. bernalii O. bernalii O. bernalii O. bernalii O. bernalii O. bernalii O. grandiflorum O. grandiflorum O. grandiflorum O. grandiflorum
89 0 23 18 32 47 68 52 39 0 60 0 0
11 0 2 16 14 2 1 16 11 0 14 26 0
0 98 21 19 14 11 18 12 22 16 12 17 87
0 2 38 32 30 26 9 15 21 25 5 36 6
0 0 16 15 10 15 3 3 4 59 2 21 7
0 0 0 0 0 0 0 1 3 0 6 0 0
4252 1559 355 758 3556 159 2553 4211 12661 32 2809 87 86
1 ¼ camoensine; 2 ¼ camoensidine; 3 ¼ guianodendrine; 4 & 5 ¼ unassigned; 6 ¼ anagyrine. EIMS (4), m/z (int.): 234 (Mþ, 25), 233 (45), 206 (37), 177 (24), 150 (14), 136 (10), 123 (70), 122 (100), 84 (47). EIMS (5), m/z (int.): 230 (Mþ, 54), 118 (57), 112 (100), 84 (37).
49
place the monospecific Guianodendron in the Bowdichia clade, sister to the core genistoids (Cardoso et al., 2012b; Castellanos et al., 2017); 3 has not so far been detected in other members of the Bowdichia clade (sensu Cardoso et al., 2012b) that have been studied (Kite et al., 2013). However, analysis of nuclear DNA sequences by Castellanos et al. (2017) place Orphanodendron sister to the Bowdichia clade rather than sister to the core genistoids, and the authors conclude that this incongruence of plastid and nuclear DNA sequence data in the placement of Orphanodendron prohibits deduction of its lower level relationships. Thus the presence in Orphanodendron of 1 and 2 (shared with Camoensia) together with 3 (shared with Guianodendron) is intriguing given the apparent uncertainty of placements in current phylogenies. Acknowledgements Analyses of Orphanodendron were made possible by the sar Castellanos generous donation of material to RBG Kew by Ce s, Colombia). Gwilym Lewis (RBG, Kew) (Universidad Santo Toma and Domingos Cardoso (Universidade Federal da Bahia) kindly helped to select material for analysis. Appendix A. Supplementary data
therefore provides strong support for plastid and nuclear DNA sequence data that place the genus in the genistoid clade of Papilionoideae (Castellanos et al., 2017) and not in Caesalpinioideae. Within the genistoid clade, the relationships of Orphanodendron are uncertain. Phylogenetic analyses of plastid DNA sequences of Castellanos et al. (2017) place Orphanodendron sister to Camoensia as an early-branching lineage of the core genistoid clade, but with low confidence. This placement sister to Camoensia gains some support from the shared presence of camoensine (1) and camoensidine (2) as major alkaloids. Both 1 and 2 are leontidinetype quinolizidine alkaloids (quinolizidine-indolizidine alkaloids) that were first reported from Camoensia, and alkaloids of this type have rarely been found in other legumes, although there are reports of leontidine-type alkaloids in Maackia amurensis Rupr. (Kinghorn et al., 1982), M. tashiroi (Yatabe) Makino (Ohmiya et al., 1991), species of Melolobium (van Wyk et al., 1988) and possibly, at trace amounts, in Polhillia involucratum (Thunb.) B.-E. van Wyk & A.L. Sch. (as Melolobium involucratum (Thunb.) C.H. Stirt.; van Wyk et al., 1988). Guianodendrine (3), a quinolizidine-indolizidine alkaloid with an unusual carbon skeleton, is only otherwise known from Guianodendron praeclarum (Kite et al., 2013). The shared presence of 3 in Orphanodendron and Guianodendron is not predicted from phylogenetic analyses of plastid DNA sequences, which currently
Supplementary data related to this article can be found at http:// dx.doi.org/10.1016/j.bse.2017.06.002. References Barneby, R.C., Grimes, J.W., 1990. Brittonia 42, 249. Cardoso, D., Queiroz, L.P., de, Pennington, R.T., Lima, H.C. de, Fonty, E., Wojciechowski, M.F., Lavin, M., 2012a. Am. J. Bot. 99, 1991. Cardoso, D., Lima, H.C., Rodrigues, R.S., Queiroz, L.P., Pennington, R.T., Lavin, M., 2012b. Taxon 61, 1074. Castellanos, C., Lewis, G.P., Banks, H., Steeves, R., Bruneau, A., 2015. Brittonia 67, 37. Castellanos, C., Steeves, R., Lewis, G.P., Bruneau, A., 2017. Brittonia 69, 62. Kinghorn, A.D., Balandrin, M.F., 1984. In: Pelletier, S.W. (Ed.), Alkaloids: Chemical and Biological Perspectives, vol. 2. Wiley, New York, p. 105. Kinghorn, A.D., Balandrin, M.F., Lin, L., 1982. Phytochemistry 21, 2269. Kite, G.C., Cardoso, D., Veitch, N.C., Lewis, G.P., 2013. S. Afr. J. Bot. 89, 176. Kite, G.C., Veitch, N.C., Grayer, R.J., Simmonds, M.S.J., 2003. Biochem. Syst. Ecol. 31, 813. Kubo, H., Ohmiya, S., Murakoshi, I., 1994. Can. J. Chem. 72, 214. Ohmiya, S., Kubo, H., Nakaaze, Y., Saito, K., Murakoshi, I., Otomasu, H., 1991. Chem. Pharm. Bull. 39, 1123. Polhill, R.M., Vidal, J.E., 1981. In: Polhill, R.M., Raven, P.H. (Eds.), Advances in Legume Systematics, vol. 1. Royal Botanic Gardens, Kew. U.K, p. 81. Santamaria, J., Khuong-Huu, F., 1975. Phytochemistry 14, 2501. van Wyk, B.-E., Verdoon, G.H., Burger, L., Greinwald, R., 1988. S. Afr. J. Plant Soil 54, 386. Wink, M., 1993. In: Waterman, P.C. (Ed.), Methods in Plant Biochemistry, vol. 8. Academic Press, San Diego, p. 197.
Contents lists available at ScienceDirect
Biochemical Systematics and Ecology journal homepage: www.elsevier.com/locate/biochemsyseco
Leontidine-type quinolizidine alkaloids in Orphanodendron (Leguminosae) Geoffrey C. Kite Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AB, UK
a r t i c l e i n f o
a b s t r a c t
Article history: Received 3 February 2017 Received in revised form 2 June 2017 Accepted 3 June 2017
Herbarium leaf fragments of the two known species of Orphanodendron (Leguminosae), O. bernalii and O. grandiflorum, were found to contain the quinolizidine alkaloids camoensine (1), camoensidine (2) and guianodendrine (3), supporting the recent phylogenetic placement of the genus in the genistoid clade of subfamily Papilionoideae rather than its traditional placement in subfamily Caesalpinioideae. © 2017 Elsevier Ltd. All rights reserved.
Keywords: Orphanodendron Quinolizidine alkaloids Camoensine Camoensidine Guianodendrine
1. Subject and source The legume genus Orphanodendron was erected in 1990 by Barneby and Grimes to accommodate O. bernalii Barneby & Grimes, a newly-described tree species from Columbia (Barneby and Grimes, 1990). Barneby and Grimes (1990) placed Orphanodendron, with some reservations, in subfamily Caesalpinioideae (sensu Polhill and Vidal, 1981) e their chosen genus name reflected their uncertainty about its subfamilial relationships. Recently, a second species, O. grandiflorum Cast. & G.P.Lewis, has been described, also from Columbia (Castellanos et al., 2015). The current report examines leaves of both species of Orphanodendron for the presence of quinolizidine alkaloids. This work was undertaken in response to recent phylogenetic analyses of DNA sequence data that placed Orphanodendron in the genistoid clade of subfamily Papilionoideae (Castellanos et al., 2017). 2. Previous work There have been no previously published chemical analyses of Orphanodendron. The present work was referred to by Castellanos et al. (2017). 3. Present study Leaf fragments of Orphanodendron and, for chemical comparison, Camoensia scandens (Welw.) J.B. Gillett and Guianodendron http://dx.doi.org/10.1016/j.bse.2017.06.002 0305-1978/© 2017 Elsevier Ltd. All rights reserved.
praeclarum (Sandwith) R. Schütz & A.M.G. Azevedo, were obtained from herbarium sheets and associated silica gel collections lodged at the Royal Botanic Gardens, Kew (K) (Table 1). Leaf fragments (c. 50 mg) were weighed exactly, powdered in a pestle and mortar and extracted in 1 ml CH3OH for 2 h. Plant residue was removed by centrifugation and the extract was dried into an Eppendorf tube under a stream of nitrogen gas. Extracted compounds were vortexed in 1 ml CHCl2/2M CH3COOH (1:1) followed by centrifugation to separate the phases. The CHCl2 layer was removed and the aqueous layer was made alkaline (pH 12) by addition of aq. ammonia. An equal volume of CHCl2 was added and following vortexing and centrifugation, the CHCl2 layer was removed and dried under nitrogen. The sample was dissolved in CH3OH (100 ml per 50 mg leaf extracted) for analysis by GC-MS using an Agilent 5975C system fitted with a 30 m 0.25 mm i.d. 0.25 mm DB-1MS column (J&W). Chromatography of split (1:10) 1 ml injections was effected using 1 ml/min He flow and a temperature gradient of 120e320 C at 5 C/min, holding at the upper temperature for 10 min. The MS was set to record standard 70eV EIMS in the range m/z 50e650. GC-MS analyses revealed quinolizidine alkaloids in all the specimens of Orphanodendron studied, although levels were relatively lower in the specimens of O. grandiflorum except the type (23504), which contained levels similar to O. bernalii (Fig. 1; Table 2). The most abundant alkaloid in several of the samples of both species had the same retention index (RI ¼ 2332), molecular mass (230 Da) and EIMS as the major alkaloid in the analysis of
48
G.C. Kite / Biochemical Systematics and Ecology 73 (2017) 47e49
Table 1 List of samples analysed. No.
Species
Collection Reference
Collection locality and date
Drying
23518
Camoensia scandens
Cultivated. Herb. Hort. Kew (K)
Air
22770
Guianodendron praeclarum
23505
Orphanodendron bernalii
Forest Dept. of Guyana field no. A69 (record no. 2353) (holotype, K), Callejas et a. 5802 (K)
23506
O. bernalii
Castellanos 703 (K)
Cult, RBG Kew, –/02/1930 Makauria, Guyana, 01/03/1934 , Columbia, Mutata 22/11/1987 , Columbia, Mutata 22/03/2012
23507 23508
O. bernalii O. bernalii
Castellanos 703 (K) Castellanos 701 (K)
00
Silica Air
23509 23512
O. bernalii O. bernalii
Castellanos 701 (K) Cogollo et al. 12796 (K)
23513 23503
O. bernalii O. grandiflorum
Cogollo et al. 12796 (K) Castellanos & Marino 451 (K)
23504
O. grandiflorum
Castellanos & Marino 600 (type, K)
23510
O. grandiflorum
Castellanos & Cepeda 750 (K)
23511
O. grandiflorum
Castellanos & Cepeda 750 (K)
Camoensia scandens and was assigned as camoensine (1), this alkaloid having been first described as the major alkaloid in C. scandens (as C. maxima Welw. ex Benth.; Santamaria and Khuong-Huu, 1975). Also present in several samples was an alkaloid (RI ¼ 2102; M ¼ 234 Da) with analytical data matching another alkaloid in C. scandens. This was assigned as camoensidine (2) the EIMS of this alkaloid matched that shown for 2 by Kinghorn and Balandrin (1984). Another alkaloid (RI ¼ 2184; M ¼ 232 Da) present in both species showed identical analytical data to guianodendrine (3) isolated from Guianodendron praeclarum (Kite et al., 2013). Two unassigned alkaloids were also detected: 4
, Columbia, Mutata 21/03/2012 00
, Columbia, Mutata 23/02/2013 00
Landazuri, Columbia, 02/08/2008 Bolívar, Columbia, 01/05/2009 Bolívar, Columbia, 02/03/2010 00
Air Air Air
Silica Air Silica Air Air Air Silica
(RI ¼ 2136) had the same molecular mass (234 Da) as 2 and a similar EIMS and 5 (RI ¼ 2174) had a molecular mass of 230 Da. Anagyrine (6, RI ¼ 2426) was detected as a minor alkaloid in some samples and was assigned against published data (Wink, 1993). 4. Chemotaxonomic significance Within Leguminosae, quinolizidine alkaloids are only known from members of the early-branching genistoid s.l. clade (sensu Cardoso et al., 2012a) of subfamily Papilionoideae (Kite et al., 2003). The presence of quinolizidine alkaloids in Orphanodendron
Fig. 1. Total ion chromatograms (left) from GCMS analyses of O. grandiflorum (23504), O. bernalii (23509), C. scandens (23518) and G. praeclarum (22770) with EIMS of camoensine (1), camoensidine (2) and guianodendrine (3) from these analyses. Structures are those given by Kubo et al. (1994) (1, 2) and Kite et al. (2013) (3).
G.C. Kite / Biochemical Systematics and Ecology 73 (2017) 47e49
Table 2 Relative amounts (% peak area in total ion GCMS chromatograms) of quinolizidine alkaloids (QAs) in samples studied. Tot. ¼ total absolute peak areas (arbitrary units). Only peaks assigned as QAs measured. Sample No
Species
1
2
3
4
5
6
Tot.
23518 22770 23505 23506 23507 23508 23509 23512 23513 23503 23504 23510 23511
Camoensia scandens Guianodendron praeclarum Orphanodendron bernalii O. bernalii O. bernalii O. bernalii O. bernalii O. bernalii O. bernalii O. grandiflorum O. grandiflorum O. grandiflorum O. grandiflorum
89 0 23 18 32 47 68 52 39 0 60 0 0
11 0 2 16 14 2 1 16 11 0 14 26 0
0 98 21 19 14 11 18 12 22 16 12 17 87
0 2 38 32 30 26 9 15 21 25 5 36 6
0 0 16 15 10 15 3 3 4 59 2 21 7
0 0 0 0 0 0 0 1 3 0 6 0 0
4252 1559 355 758 3556 159 2553 4211 12661 32 2809 87 86
1 ¼ camoensine; 2 ¼ camoensidine; 3 ¼ guianodendrine; 4 & 5 ¼ unassigned; 6 ¼ anagyrine. EIMS (4), m/z (int.): 234 (Mþ, 25), 233 (45), 206 (37), 177 (24), 150 (14), 136 (10), 123 (70), 122 (100), 84 (47). EIMS (5), m/z (int.): 230 (Mþ, 54), 118 (57), 112 (100), 84 (37).
49
place the monospecific Guianodendron in the Bowdichia clade, sister to the core genistoids (Cardoso et al., 2012b; Castellanos et al., 2017); 3 has not so far been detected in other members of the Bowdichia clade (sensu Cardoso et al., 2012b) that have been studied (Kite et al., 2013). However, analysis of nuclear DNA sequences by Castellanos et al. (2017) place Orphanodendron sister to the Bowdichia clade rather than sister to the core genistoids, and the authors conclude that this incongruence of plastid and nuclear DNA sequence data in the placement of Orphanodendron prohibits deduction of its lower level relationships. Thus the presence in Orphanodendron of 1 and 2 (shared with Camoensia) together with 3 (shared with Guianodendron) is intriguing given the apparent uncertainty of placements in current phylogenies. Acknowledgements Analyses of Orphanodendron were made possible by the sar Castellanos generous donation of material to RBG Kew by Ce s, Colombia). Gwilym Lewis (RBG, Kew) (Universidad Santo Toma and Domingos Cardoso (Universidade Federal da Bahia) kindly helped to select material for analysis. Appendix A. Supplementary data
therefore provides strong support for plastid and nuclear DNA sequence data that place the genus in the genistoid clade of Papilionoideae (Castellanos et al., 2017) and not in Caesalpinioideae. Within the genistoid clade, the relationships of Orphanodendron are uncertain. Phylogenetic analyses of plastid DNA sequences of Castellanos et al. (2017) place Orphanodendron sister to Camoensia as an early-branching lineage of the core genistoid clade, but with low confidence. This placement sister to Camoensia gains some support from the shared presence of camoensine (1) and camoensidine (2) as major alkaloids. Both 1 and 2 are leontidinetype quinolizidine alkaloids (quinolizidine-indolizidine alkaloids) that were first reported from Camoensia, and alkaloids of this type have rarely been found in other legumes, although there are reports of leontidine-type alkaloids in Maackia amurensis Rupr. (Kinghorn et al., 1982), M. tashiroi (Yatabe) Makino (Ohmiya et al., 1991), species of Melolobium (van Wyk et al., 1988) and possibly, at trace amounts, in Polhillia involucratum (Thunb.) B.-E. van Wyk & A.L. Sch. (as Melolobium involucratum (Thunb.) C.H. Stirt.; van Wyk et al., 1988). Guianodendrine (3), a quinolizidine-indolizidine alkaloid with an unusual carbon skeleton, is only otherwise known from Guianodendron praeclarum (Kite et al., 2013). The shared presence of 3 in Orphanodendron and Guianodendron is not predicted from phylogenetic analyses of plastid DNA sequences, which currently
Supplementary data related to this article can be found at http:// dx.doi.org/10.1016/j.bse.2017.06.002. References Barneby, R.C., Grimes, J.W., 1990. Brittonia 42, 249. Cardoso, D., Queiroz, L.P., de, Pennington, R.T., Lima, H.C. de, Fonty, E., Wojciechowski, M.F., Lavin, M., 2012a. Am. J. Bot. 99, 1991. Cardoso, D., Lima, H.C., Rodrigues, R.S., Queiroz, L.P., Pennington, R.T., Lavin, M., 2012b. Taxon 61, 1074. Castellanos, C., Lewis, G.P., Banks, H., Steeves, R., Bruneau, A., 2015. Brittonia 67, 37. Castellanos, C., Steeves, R., Lewis, G.P., Bruneau, A., 2017. Brittonia 69, 62. Kinghorn, A.D., Balandrin, M.F., 1984. In: Pelletier, S.W. (Ed.), Alkaloids: Chemical and Biological Perspectives, vol. 2. Wiley, New York, p. 105. Kinghorn, A.D., Balandrin, M.F., Lin, L., 1982. Phytochemistry 21, 2269. Kite, G.C., Cardoso, D., Veitch, N.C., Lewis, G.P., 2013. S. Afr. J. Bot. 89, 176. Kite, G.C., Veitch, N.C., Grayer, R.J., Simmonds, M.S.J., 2003. Biochem. Syst. Ecol. 31, 813. Kubo, H., Ohmiya, S., Murakoshi, I., 1994. Can. J. Chem. 72, 214. Ohmiya, S., Kubo, H., Nakaaze, Y., Saito, K., Murakoshi, I., Otomasu, H., 1991. Chem. Pharm. Bull. 39, 1123. Polhill, R.M., Vidal, J.E., 1981. In: Polhill, R.M., Raven, P.H. (Eds.), Advances in Legume Systematics, vol. 1. Royal Botanic Gardens, Kew. U.K, p. 81. Santamaria, J., Khuong-Huu, F., 1975. Phytochemistry 14, 2501. van Wyk, B.-E., Verdoon, G.H., Burger, L., Greinwald, R., 1988. S. Afr. J. Plant Soil 54, 386. Wink, M., 1993. In: Waterman, P.C. (Ed.), Methods in Plant Biochemistry, vol. 8. Academic Press, San Diego, p. 197.