Castanospermine in Alexa species

Phytochem~stry,Vol 27, No 5, pp 1403~1404,1988 Pnnted I” Great Bntaln

0031-9422/88%300+000 Pergamon Press plc

CASTANOSPERMINE

IN ALEXA

SPECIES

ROBERT J. NASH, LINDA E FELLOWS, JANET V. DRING, CHARLES H. STIRTON, DAVID CARTER,* MERVYN P. HEGARTY~ and E. ARTHUR BELL Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3AB, U.K.; *School of Pharmacy, Umverslty of London, 29/39 Brunswick Square, London, WClN lAX, U.K.; tC.S.I.R.0, St Luaa, Queensland 4067, Austraha (Recewed 20 November 1987) Key Word Index-&q

Legummosae,

castanospermme,

polyhydroxyalkalmd;

chemotaxonomy

Abstract-Castanospermine, a physIologIcally active polyhydroxylated mdohzldme alkaloid first isolated from seeds of Castanospermum australe, has been isolated from the dried pod of Alexa lelopetala and tentatively identified m seven other species of the same genus

INTRODUCTION

OH

Castanospermme 1, an alkaloid first Isolated from the seeds of the monotyplc Austrahan rainforest and riverme tree Castanospermum australe [l] 1s an mhlbitor of plant, insect and mammalian cc- and /?-D-glucosidases m vitro [2, 31 and has been shown to’ affect the processmg of glycoprotems tn uluo by mhibiting a-glucosidases I and II [4]. The alkaloid alters glycogen metabolism m rats [S] and mhlblts the growth of HIV 1 and 2 in C8166 cells [6].

Table

1 Castanosperrmne

OH

RESULTS AND

We are now able to report that castanospermine has been isolated from the dried pod of another legume,

concentration

m AIexa and Castanospermum

Species

Collector(s)

Alexa canaracunensrs PIttIer

Holst and Llesner 2823 Steyermark 75425 Magmre, Steyermark and Magmre 53510 Ducke 286 Archer 8061 Archer 8061 Steyermark, Davldse and Guanchez 122206 Wurdack and Monacluno 39681 Davis 1056 Fanshawe 3077 Fanshawe 3077 Cardona 2485 Forest Herbarmm Surmam 4308 Hegarty s n Hegarty s n

Alexa cowann Yakovlev

Alexa gran@Iora Ducke

Alexa hermuuana Ramlrez

Alexa rmperatrrcls (Schomb

)Badl

AIexa lewpetala SandwIth

Alexa superba R S Cowan Alexa wachenhennn Benolst Castanospermum australe A Cunn

-

DISCUSSION

Part of plant

Herbarium material IS held at R B G Kew Results are the mean of two analyses 1403

leaf pod seed leaf pod

% dry weight 018 0 12 1 13 003 0.002

pod seed leaf

0 57 001 139 042

leaf

0.02

leaf Pod seed leaf leaf pod leaf Pod

0003 0 10 120 0 17 016 0 056 027 0003

leaf

1404

R J

NASH

Alexu le~opetala Sandwtth, collected In 1931 m Guyana (Tmamu Line, Lower Cuyum River-Davis, Forest Dept. 1056) The IdentIty of the Isolate with authentic castanospermme has been estabhshed by ‘H and 13C NMR and EIMS. The yield was 0.09%. Castanospermine was also tentatively ldentlfied from dried herbarium material m seven other Alexa species The concentration of castanospermme detected by gas chromatography in Alexa and Castanospermum extracts are shown m Table I It should be noted that drymg and storage of the herbarlum material may have affected the levels of the alkaloid Ripe C rrustrale seeds can contam 1 3% fresh weight of castanospermine Alexa spp are native to the wet lands of Guyana, Surmam, French Guiana, Venezuela and the Brazlhan Amazon Basin but despite their geographlcal separation from Cabtanospermum ausrrale the possession of castanospermme and a large number of other morphological and anatomical features m common suggest that the two genera are closely related A detailed taxonomrc study will be reported separately (Stirton, C H , m preparation) EXPERIMENTAL lrolatron of tuctanospermrnr 1I g of dried Alexa letopetala pod was finely ground and extracted with 75% &OH (3 x 55 ml) After filtration the extract was coned under red pres to 30 ml and cdstanospermme Isolated by ran exchange chromatography [l] The alkaloid was obtamed as d VISCOUSsyrup after freeze-drymg fractions found to contam the compound by high voltage paper lonophoreals [I] ‘H and 13C NMR Comparison of 89 55 MHz ‘H NMR and 22 5 MHz “C NMR spectra of the alkalmd isolated from A lefopetala and authentic castanospermme m D,O showed them to be the same Calculation of proton-proton couphngs for H, and H,r showed the alkaloid to be castanospcrmme and not 6. epicastanospermme [7] EIMS A low resolution mass spectrum of the dlkalmd from

et al

A letopetala was virtually Identical to that of authentic castanospermme with intense ions at m/z 189, 172, 154 and 145 Gas chromatoyraphlc ancrl~v~of tusruno~permmc Dry herbarium material of 8 Alexa species and Cuslanoapermwn uustrale was finely ground and extracted m 75% EtOH (100 mg,‘ml) for 24 hr I ml ahquots of the extracts were dpphed to Pasteur pipette columns of strongly acidic catjon exchange rcsm (Amberhte CGl20) in the H’ form After washing with H,O dnd

I M pyndme, castanospermme was displaced from the column with 2 M NHiOHand fractions combined .md frceLe-dried for gas chromatogrdphic annlq\ls 200 /II Sigma Sil A wds added per sample and the TMS derlvatlve of castanozpermlne chromdtographed on a glass column (I 5 m x 4 mm) packed with 3% OVI [8] The concentration of castanospcrmlne In the extracts wd\ determined by comparison with the pure compound

Atknowledyements financial

support

We thank (R J N )

the Bentham-Mouon

Trust

for

REFERENCES

Hohenschutz, L. D, Bell. E A. Jewess. P J. Leworthy. D P. Pryce. R J , Arnold, E and Clardy J (1981) PhytoLhemturv 20, 811 Saul, R , Chambers, J P, Molyneux, R J dnd Elbem, A D (1983) Arch Blothem BlophJs 221. 593 Campbell. B C , Molyneux, R J and Jones, K C (1987) J

Chem Ecol 13, 1759 Pan, Y T, Horl, H , Snul, R . Sanford, B A, Molyneux, R J and Elbem, A D (1983) BZO~~I~~II~III22. 3975 Saul, R. Ghldom, J J, Molyneuu, R J and Elbem, A D (1985) Proc Nutl Acrsd Scl II SA 82,9? Tyms. A S ~Berrle, E M _Ryder, T 4 r Nash, R 1. Hrgarty, M P, Taylor. D L, Mobberley M A ~Davis. I M. Bell, E A, Jefines, D J, Tdqlor-Robinson. D and Fellows, L E (1987) Lancer Ort 31st, 1025 Molyneux, R J, Roltman. .I N . Dunnhelm, G Szumtlo, T and Elbem, A D (1986) Arch Bwchern Bwph~~ 251, 450 Nash. R i Goldstem, W 9 _ Etanc, S V and Fel!o~~,. L E (1986) J Chromatoq 366. 43 I