classify quinolizidine alkaloids simply into pre-cytisine, cytisine, post- cytisine, sparteine, matrine, ormosanine, lamprolobine and anabasine types (SALATIZ~'O ...
Runt |vstemuti(s und Eudlution
P1. Syst. Evol. 143, 167--174 (1983)
© by Springer-Verlag 1983
Chemogeographical Evolution of Quinolizidines in Papilionoideae 1 By Antonio Salatino and Otto R. Gottlieb
(Received May 21, 1982)
Key Words: Leguminosae, Papilionoideae, Bossiaeeae~ Genisteae, Liparieae, Sophoreae, Thermopsideae.--Quinolizidine alkaloids, biochemical evolution, ecogeographieal evolution. Abstract: Characterization of the predominant biogenetic quinolizidine types, together with the determination of oxidation levels and skeletal specializations of such alkaloids contained in Papilionoideae genera led to the recognition of several evolutionary lines in this subfamily. The results are consistent with the most recent views on the subject based on morphology and indicate quinolizidine alkaloidal evolution to have proceeded by skeletal specialization in tropical regions and by variation of oxidation level in temperate regions.
The analysis of Papilionoideae genera with respect to structural characters of their quinolizidine alkaloids led to a correlation which suggested phylogenetic trends and geographic radiations. The conclusions were based on the quantification of two structural parameters, oxidation values and skeleton frequency, /br each compound. Both values were derived from a unified biogenetic scheme encompassing all f u n d a m e n t a l quinolizidine skeletons of the Papilionoideae (SAL~TlZ~O& GOTTLIEB 1980, 1981 a). The biogenetic relationships linking the more i m p o r t a n t skeletons are shown in Fig. 1. Since their precise biosynthetic relation, however, is not yet completely clear, we prefer lateron to classify quinolizidine alkaloids simply into pre-cytisine, cytisine, postcytisine, sparteine, matrine, ormosanine, lamprolobine and anabasine types (SALATIZ~'O& GOTTLIE~ 1981 b). i Part XXII in the series "Plant Chemosystematics and Phylogeny". For Part XXI (see FERNANDES DASILVA~5 al. 1982).
1"2 P1. Syst. Evol.,Vol. 143~No. 3
168
A. SALATINO~50. R. GOTTLIEB:
,o, CH20H lupinine (pre-cytisine type)
cytisine (cytisine type)
argentine (post-cytisine type)
saphoramine (matrine type)
quinolizidine skeleton
ormosanine {ormosanine type} Fig. 1. Simplified scheme of proposed biogenetic relationships (SALATINO& GOrTLIEB 1981a) of the main types of quinolizidine alkaloids exemplified by some of their representatives
I t is t h e p u r p o s e of t h e p r e s e n t p a p e r to show t h a t a b s e n c e o f precise b i o s y n t h e t i c k n o w l e d g e is n o t a n o b s t a c l e t o t h e m e a n i n g f u l q u a n t i f i c a t i o n a t least of t h e o x i d a t i o n s t a t e of m i e r o m o l e c u l a r m a r k e r s in p h y l o g e n e t i c studies. On t h e c o n t r a r y , t h e p r e s e n t d a t a are n o t o n l y c o n s i s t e n t w i t h t h e p r e v i o u s results, b u t a d d i t i o n a l l y i l l u m i n a t e t h e chemical phenomena which accompany quinolizidine evolution upon a d a p t i v e r a d i a t i o n of Papilionoideae genera.
Methods Calculation of the oxidation values of quinolizidine alkaloids: The oxidation state for any single carbon atom of a molecule is calculated by adding the following values for each of its four bonds : minus signal ( 1) for each - - H, 0 for each - - C and + 1 for each - - X (heteroatom) (HENDRICKSON& al, 1970). Each carbon atom in a quinolizidine can be so labeled with its oxidation state and the sum of these oxidation states may be compared to the analogous sum in another quinolizidine to ascertain the relative oxidation levels. This comparison is meaningful only for molecules containing an identical number of carbon atoms. For the present purpose each molecule, i.e. quinolizidine, is thus better characterized by the mean of the oxidation states of its carbon atoms (O) (Table 1).
Evolution of Quinolizidines in
Papilionoideae
169
Table 1. Determination of oxidation (0) and specialization (S) values exemplL fled with some selected representatives of the main types of quinolizidine alkaloids Alkaloid
h
x
c
O
r
d
S
lupinine cytisine argentine sophoramine ormosanine
19 14 26 20 35
5 8 18 8 9
10 11 23 15 20
- - 1.400 --0.545 -0.345 --0.800 - - 1.300
2 7 8 6 5
120 8 1 7 12
0.0167 0.8750 8.0000 0.8571 0.4167
Notes: 0 = (x -h)/c; S = r/d; x number of C--X (X heteroatom) bonds; h number of C - - H bonds; c number of C atoms; r number of metabolic steps, as defined in a biogenetic map (SALATINO~5 GOTTLIEB1981 a), required to arrive at the skeleton in question ; d number of known representatives of the skeleton in question and of all derived skeletons.
Calculation of the specialization values of quinolizidine skeletons: Quinolizidine skeletons of Papilionoideae have been defined (SALaTtNO & GOTTLmB 1981b). Each skeleton is represented in nature by a number of derivatives (M~ARS& MABaY1971, SALATIN0& GOTTLIEB1980). The smaller this number the more specialized is the skeleton. The specialization of each skeleton (S) was determined as before (SALAT~NO& GOTTL*EB1980, 1981 a) dividing the number of reaction steps leading to the skeleton (as defined in the biogenetic scheme) by the number of its derivatives. This latter number refers not only to the actual compounds which possess the skeleton in question, but also to the compounds which belong to derived skeletal types (Table 1). Calculation of the evolutionary advancement parameters for genera: A species may contain several quinolizidines. The averages of their 0 and S values are taken to represent the evolutionary parameters (EAo, EAs) of the species. The mean EA o and EAs values for species are taken to characterize their genus. Calculation of the latitudes of occurrence for genera: Latitude values are taken to be represented by the midpoints of the geographic range of each genus (HuTemNSO~ 1964, SC~ULZE-MENz1964, A JaY SHAw 1973).
Results E v o l u t i o n a r y a d v a n c e m e n t p a r a m e t e r s for genera of Papilionoideae b a s e d on the o x i d a t i o n values of their q u i n o l i z i d i n e alkaloids (EAo) a n d the specialization v a l u e s of t h e i r q u i n o l i z i d i n e skeletons (EAs) are p l o t t e d on Fig. 2. C l u s t e r i n g of the p l o t t e d p o i n t s according to the q u i n o l i z i d i n e t y p e s which p r e d o m i n a t e in the respective g e n e r a reveals, n e a r the origin of the plot, the existence of a p r e - c y t i s i n e cluster, characterized b y low E A o a n d E A s values. F r o m here, in three directions, r a d i a t e a n o r m o s a n i n e cluster, a m a t r i n e cluster a n d a 12"
170
A. SALATINO ~50. B. OOTTLIEB:
EAs •
BENISTEAE THERMOPSIDEAE O SOPHOREAE • LIPARIEAE PODALYRIEAE Q BOSSlAEEAE ..... CYTISINE MATRINE .... ORMOSANINE . . . . . . . . . POST-CYTISINE . . . . . . . . PR E-CYTISlNE
ORM AM
2.0.
.-9
I
"" ORM IM 1,5
1
I
o.9!
THE .I)
0.8"
o'" 0.7"
LAB
O~,MD
SOP~
'
GOE
.~
.j~4D
0.6"
l
ADE
,.
/
I
./.J~g'BAp
0.5-
p~, , / ~ - RET
/
0.4
/-"
( AMT
0.3
if" LUP ME
,e. 0.2
/
~VIR
;
W:. . . . . "'atuP LIP
-1.s
/
-I'.2
AM 6 CA° ......... dOAL
-I'.I
-l',o
-o~9
-o'.s
-o'.~
-o16
-o~s
EAo
Fig. 2. Correlation of evolutionary advancement parameters with respect to the oxidation state (EAo) and the skeletal specialization (EAs) of quinolizidine alkaloids in Papilionoideae genera: ADE Adenocarpus, AMD Ammodendron, AMT Ammothamnus, ANA Anagyris, ARG Argyrolobium, BAP Baptisia, CAD Cadia, CAL Calpurnia, CYT Cytisus, GEN Genista, GOE Goebelia,HOV Hovea, KEY Keyserlingia, LAB Laburnum, LIP Liparia, LUP AM Lupinus (America), LUP ME Lupinus (Mediterranean), OgM AM Ormosia (America), ORM IM Ormosia (Indomalasia), PET Petteria, PIP Piptanthus, RET Retama, SAR Sarothamnu~, SPA Spartium, TEM Templetonia, THE Thermopsis, ULE Ulex, VIR Virgilia. Clusters composed according to the presence of the predominant biogenetic quinolizidine types.
cytisine cluster. Alkaloid variation in the ormosanine cluster proceeds by skeletal specialization, the EA o values remain low. I t is the cytisine cluster which is characterized by a, strong increase in the oxidation level of its alkaloids, the EAs values remaining relatively low. The matrine cluster assumes an intermediate position.
Evolution of Quinolizidines in Papilionoideae
171
Fig. 2 will now be analysed from the morphological and the ecogeographical standpoints. Initially, with respect to the former, the diagram is fully consistent with the most recent treatment of the Papilionoideae edited by POLHILL & RAVEN (1981). The Cadia group (CAD) is indeed considered basic in the Sophoreae tribe which has branches to the Sophora group (CAL, SOP with AMT, GOE and K E Y in sections, AMD) on one hand and to the Ormos'ia group (ORM AM, O g M IM) on the other (PoLItlLL 1981), as suggested by the chemical data of Fig. 2. There is evidence that the basic Sophoreae preceded all other tribes, including the Genisteae which are divided into the subtribes Lupininae (LUP, L U P AM) and Genistinae with a Cytisus group (CYT, with SAR as section, P E T , LAB), a Genista group (RET, GEN, ULE) and '~outliers" (ARG, SPA, ADE) (BISB• 1981). Again, the difference between the two subtribes becomes obvious through the EAo/EA s correlation based alkaloid data. Fig. 2 suggests, furthermore, an evolutionary sequence for the Genisteae. As expected, however, since the Cytisus group and the Genista group show too many intermediates and cross-links tbr ibrmal recognition (BIsBY 1981), no hint concerning the separation of the subtribe is offered by the diagram, except in the ease of ADE which is indeed well-defined as an "outlier". Besides quinolizidine alkaloids, this genus'contains, together with Laburnum and Crotalaria, pyrrolizidine alkaloids. According to TUR~'ER (1981), another tribe which stems from Sophora-like taxa is constituted by the Thermopsideae. The author's belief t h a t its woody genera Piptanthu8 (PIP) and Anagyris (ANA) most cl9sely resemble members of the Genisteae is well consubstantiated in Fig. 2. Other genera include Baptisia (BAP) and Thermopsis (THE). The enormous geographical spread of the latter justifies the higher specialization of its quinolizidine skeletons. Finally, alkaloidal data are not inconsistent with POLH1LL'S(1981) provisional supposition that the genera of Podalyrieae (POD, VIR) and Liparieae (LIP), as well as of Bo.ssiaeeae (TEM, HOV) have attinities with the tropical tribes somewhere near the borderline of the Nophoreae and the Tephrosieae. Alkaloid data have been collated previously for use in chemosystem aries. " Y e t " , in the words of B IsBY ( 1981), :'despite the wealth of the alkaloid information, it remains puzzling to analyse. For instance if one accepts that the genus Lupinus exists on morphological grounds then one can accept FaUOERaS' (1971) suggestion that Lupinu8 is characterized by the abundance of alkaloids in the biosynthetic chain from lupinine to angustitbline, and also by the presence of sparteine unknown in other genera. But tbr confirmation of the delimination of
172
A. SALATINO & O.
l=~. G O T T L I E B :
LATITUDE 0 AMD
6o!
s~
• /T ."'" .//
CYT
'" GEN (pl.~, '. • ~ •~ ' - : - - - . ~
BAP qIDTHE" ~ ' ' ~ D ~ " ~
~AMT ! !
•
.ILAB
.~.fr
./ ULE
i/ .... i ~A,~ ~
~ot
i / ).
/
A
0°.
i
I ; /
id.
2~
3oL
X,
/ /
/b
i ...................
LLP
"1.8
GENISTEAE THERMOPSIDEAE O SOPHOREAE • LIPARIEAE I[] PGDALYRIEAE [] BOSSIAEEAE ..... CYTISINE - MATRINE .... ORMOSANINE . . . . . . . . . . POST-CYTISINE . . . . . . . . PRE-CYTISINE
CADI )/OORM AM
-1:2
"1'.1
~v,R q'.O
-019
-0;8
-077
-0:6
-O;E'
EA•
Fig. 3. Correlation of evolutionary advancement parameter with respect to the oxidation state of quinolizidine alkaloids (EAo) and mean latitude of occurrence of Papilionoide genera. For meaning of abbreviations see text to Fig. 1.
the genus the data is useless. Of 53 species recorded, no one alkaloid is found in more t h a n 30 species and nearly all the alkaloids in the chain are found in larger numbers of species in other genera. The rarities, augustifoline and multiflorine are found in 5 and 6 species respectively". And here one must make ~ fundamental point: Micromolecular data will remain "puzzling" until this type of presence/absence criterium is associated with some unifying evolutionary concept applicable to the selected biogenetic micromolecular group of systematic markers (GoTTLIEB 1982), such as, in the present ease, the oxidation values and the skeleton specializations of quinolizidine alkaloids.
Evolution of Quinolizidines in Papilionoideae
173
The analysis of Fig. 2 from the ecogeographical standpoint indicates quinolizidine alkaloidal to have proceeded in tropical regions by skeleton specialization and in temperate regions by variation of oxidation level. The latter deduction, forcefully conveyed in a correlation of EA o parameters and mean latitudes of occurrence for genera (Fig. 3) is highly meaningful. Clearly, adaption of tropical members of the Papilionoideae to temperate, northern habitats required the use or acquisition of oxidizing enzyme systems for the production of less saturated, and hence probably more toxic eytisine types. In the light of this postulate, even the position of the seemingly aberrant points representing Adenocarpus (ADE) and Argyrolobium (At~G) (Fig. 3) makes sense. The quinolizidine alkaloids of Adenocarpu8 are far too reduced for the high mean latitude of occurrence of this genus. But then, as has already been stated, the defensive function is here taken over by pyrrolizidine alkaloids which are highly toxic. In opposition, the quinolizidine alkaloids of Argyrolobium are far too oxidized for the low mean latitude of occurrence of this genus. But then, Argyrolobium occurs also as far north as the Mediterranean and India where it may have acquired its cytisine types which should make it highly competitive for radiation towards the south (SALATINO & G OTTLIEB 1980). Discussion
The observed dependence between the latitude of occurrence of genera and the oxidation level of their quinolizidine alkaloids recalls to mind that quinolizidine alkaloid biosynthesis shows a circadian r y t h m which is positively correlated with illumination (W~NK & al. 1980). Indeed, quinolizidine production is the first alkaloid biosynthesis to have been localized in chloroplasts (WIxK & HAgT~*AXN 1980) and is positively correlated with the chlorophyll content of the cells (W~NK & al. 1981). Also localized in the chloroplast are the biosyntheses of the alkaloid precursor lysine (HART~aA~N& al. 1980) and of the reductive enzyme N A D P H . And this is of course where light enters the picture. Could it be that smaller light intensities in more northern regions diminish the rednctive pressure on the quinolizidine systems ? References
A~RYSHAW,H. K., 1973: Willis' Dictionary of the Flowering Plants and Ferns. 8 th ed. - - Cambridge: University Press. BISEy, F. A., 1981 : Genisteae (ADANS.)BENTH.- - In POLHILL, R . ~V[., RAVEN, P. H., (Eds.): Advances in Legume Systematics, p. 409---425. - - K e w : Royal Bot. Gard.
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A. SALATIN0~5 al. : Evolution of Quinolizidines in Papilionoideae
FAUGERAS, G., PARIS, R., 1971: Nouvelles recherches phytochimiques sur les Papilionac~es-G6nistges d'Europe. - - Boissiera 19, 210--218.
FERNANDES DASILVA, M. F., DAS, G., GOTTLIEB, O. R., EHRENDOB, FER, F., 1983: Major alkaloids and coumarins in Rutaceae: Suggestions for a natural system and evolutionary interpretation of the family. -- PI. Syst. Evol. (in press). GOTTLIEB, O. R., 1982: Micromoleeular Evolution, Systematics and Ecology. Berlin-Heidelberg-New York: Springer. HAaTMA~N, T., SCHOOFS, G., WINK, M., 1980: A chloroplast -- localized lysine decarboxylase of L u p i n u s polyphyllus, the first enzyme in the biosynthetic p a t h w a y of quinolizidine alkaloids. - - F E B S Letters 115, 35---38. HENDRICKSON,J. B., CRAM,D. J., HAMMOND,G. S., 1970: Organic Chemistry. 3 r d ed. - - New York: McGraw~Hill. HUTCHINSON, J., 1964: The Genera of Flowering Plants, Vol. 1, 297--366. - Oxford: Clarendon Press. POLHILL, 1~. M., 1981 : Sophoreae SPRENGEL. - - I n POLHILL, R. M., RAVEN, P. H., (Eds.) : Advances in Legume Systematics, p. 213--230. - - K e w : Royal Bot. Gard. 1981: Bossiaeeae (BENTH.) HUTCH. - - I n POLHILL, R. M., RAVEN, P. H., (Eds.) : Advances in Legume Systematics, p. 393--395. - - K e w : R o y a l Bot. Gard. - - 1981: Podalyrieae BENT~. - - I n POLHILL, R. M., RAVEN, P. H., (Eds.): Advances in Legume Systematics, p. 396--397. - - K e w : Royal BoA. Gard. - - I~AVEN, P. H., (Eds.), 1981: Advances in Legume Systematics, P a r t l , - K e w : Royal Botanic Gard. SALATINO, A:, GOTTLIEB: O. R., 1980: Quinolizidine alkaloids as systematic markers of the Papilionoideae. - - Biochem. Syst. Ecol. 8, 133--147. - - - - 1981a: Quinolizidine alkaloids as systematic markers of the Genisteae. Biochem. Syst. Ecol. 9, 267--273. - - 1981b: A chemo-geographical perspective of the evolution of quinolizidine bearing Papilionoideae. - - Revta. Brasil. Bot. 4, 83--88. SCHULZE-MENz,G. K., 1964: Reihe Rosales. - - I n MELCHIOR,H., (Ed.) : Engler's Syllabus der Pflanzenfamilien, 12th ed., Vol. 2, 193--242. - - Berlin: Gebrueder Borntraeger. T t'RXER, B. L., 1981: Thermopsideae YAKOVLEV.---- In POLHILL, R. M., RAVEN,P. H , (Eds.) : Advances in Legume Systematics, p. 403--407. - - Kew : Royal BoA. Gard. WINK, M., HARTMANN, T., 1980: Production of quinolizidine alkaloids by photomixotrophic cell suspension cultures: biochemical and biogenetic aspects. - - P l a n t a Medica 40, 149--155. - - W rTTE, L., 1980 : E n z y m a t i c synthesis of quinolizidine alkaloids in lupin chloroplasts. - - Z. Naturforsch. 35 c, 93--97. WITTE, L., HARTMANN,T., 1981 : Quinolizidine alkaloid composition of plants and of photomixotrophic cell suspension cultures of Sarothamnus scoparius and Orobanche rapum-genistae. - - P l a n t a Medica 43, 342-- 352. -
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Addresses of the authors: Prof. Dr. ANTONIO SALATINO,I n s t i t u t o de Biocigncias ; Prof. Dr. 0 TTOg . G 0TTLIEB,I n s t i t u t o de Quimica, Universidade de S~o Paulo, 05508 S~o Paulo, SP, Brazil.
