Chua, C H

Hassan, Hazimah A

Khan, Mohammad N

Lajis, Nordin H

Retnam, Ananthy

Sargent, M V

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Indian Journal of ChemistryVol. 36B, February 1997, pp. 206-207Securinega alkaloids: Reinvestigation onthe fresh leaves of Breynia coronata(Euphorbiaceae)Nordin H Lajis", Ananthy Retnam, Hazimah A Hassan,Mohammad N Khan\, C H Chua' & M V Sargent!Department of Chemistry, University Pertanian Malaysia,43400UPM Serdang, Selangor, Malaysia"Department of Chemistry,University Malaya, 59100 Lembah Pantai,Kuala Lumpur, Malaysia'Department of Chemistry,The University of Western Australia,Nedlands 6009, Western Australia, AustraliaReceived 14 May 1996; revised and accepted 16 August 1996From the fresh leaves of Breynia coronata, the secu-rinega alkaloids securinine 1, ent-norsecurinine 2 andvirosecurinine 3 have been isolated. These constitu-ents are different from those isolated from the samespecies earlier which was collected from a differentpopulation in peninsular Malaysia.Securinine, the major alkaloid of the securinegagroup of alkaloids, has been isolated from a num-ber of species from the family Euphorbiaceae! - 3.We have been working on the isolation of alka-loids from Breynia coronata and in the process,securinine was isolated from the fresh leaves col-lected from Langkawi Island in Malaysia. Investi-gation on the fresh leaves collected from the stateof Selangor (in the middle part of peninsular Mal-aysia) however yielded only viroallosecurinine 4and ent-phyllanthidine 54. Our failure to detectsecurinine from the latter prompted us to reinves-tigate the identity of its alkaloid constituents.Securinine has been reported as a crystallinesolid and stable, while norsecurinine as an oilwhich is rather unstable on storage", In our inves-tigation compound NAl (see Experimental) alsoappeared as a light brown oil and was found tobe unstable on storage. Its mass spectrum gaveM+ peak at mJz 203 which was consistent withthe molecular formula C12H13N02. The majorfragments in the mass spectrum strongly suggest-ed that the alkaloid belongs to the securinega typewith ring-A consisting of a pyrrolidine ring as innorsecurininev'. The lH NMR spectrum was inagreement with gross formulation of ent-norsecurinine 24.From the 1H NMR spectra of securinine, allo-securinine", (4~)-4-methoxysecurinan-ll-oneNoteH1H2H3H4 H 5(phyllanthine), (2a,4a)-4-methoxysecurinan-ll-one (securitinine)", ent-norsecurinine, 4-methoxy-norsecurinine" and ent-phyllanthidine9 it is appar-ent that the signals for ~-H2 should appear at 02.10-2.79 and that of a-H2 at 3.24-3.90 ppm,both as dd. If the configurational relationship ofthe proton at C2 is a, the signal for H14(d) willappear at higher field than that for HIS (dd)while the reverse is true if the same proton is in~-configuration. These 1H NMR spectral charac-teristics indicated NAl to be ent-norsecurinine 2.It is interesting to note that the reported chemicalshifts for H2, H14 and HIS in norsecurinine areat 2.9-3.4 (m), 6.50 (d), and 6.75 ppm (dd), re-spectively and those in viroallosecurinine are at3.65 (dd), 6.66 (d), and 6.83 (dd)". In these reortsthe configuration of H2 was concluded as ~. Thechemical shift patterns of H2, H14 and HIS forthese two compounds however indicated that theconfiguration of H2 should be a based on thereasons mentioned earlier. In this report we there-fore wish to revise the earlier claimed norsecuri-nine'? and viroallosecurinine? as epi-norsecurinineand virosecurinine, respectively.The 13C NMR spectrum of NAl showed 12peaks and the assignment of which was made onthe basis of the 13C NMR spectra for ent-norsecurinine", securinine and allosecurinine", It isalso interesting to note that l3C NMR spectra ofallosecurinine" and virosecurinine" appeared tobe similar. The 'H and Be NMR spectra as wellas TLC of NA2 were identical with those of viro-securinine 3.\Experimental SectionExtraction. The fresh leaves (4.5 kg) of B. coro-nata were repeatedly extracted with fresh metha-nol until the final extract (four times) gave a nega-tive Meyers test for alkaloids. The methanol ex-tracts were combined and evaporated under vacu-um to give 300 g of a dark brown viscous residuewhich was dissolved in CHCl3 and extracted withpet. ether. The CHCl3 layer was extracted with1% H2S04• The acidic layer was basified withNa2C03 to pH 8 and extracted with CHCI3. Thechloroform extract was then evaporated to dry-ness under vacuum to give 6 g of a crude solid.The aqueous layer was further basified to pH 12using ammonia and extracted with BuOH whichon evaporation in vacuo gave 25 g of another sol-id.Isolation of alkaloids. The chloroform extractrevealed 3 spots on TLC which gave positive testfor alkaloids. It was then subjected to columnchromatography over silica gel (mesh 70-230).From the elution with CHCkCH30H a set of 17fractions (each nearly 50 ml) was collected; themajor constituents were found to be present infractions 2 and 3. Fraction 3 was further fraction-ated by column chromatography and the fractionscontaining major alkaloids were combined andsubjected to preparative TLC giving three com-pounds designated as NAl, NA2 and NA3. Com- -pound NAl was a light brown oil and identifiedNOTES 207as ent-norsecurinine 2. Compound NA2 was fur-ther purified by recrystallization from ethyl acet-ate to give 75 mg of virosecurinine 3, as colour-less prisms (m.p. 125-27°) while NA3 was recrys-tallized from CHCI3 to give 50 mg of securinine 1as a crystalline solid (m.p. 140-42°). Fraction 2was subjected to preparative TLC which fur-nished pure virosecurinine and securinine.References1 Arbain D, Byrne L T, Cannon J R, Engelhardt L M &White A H, Awt J Chern,43, 1990,439.2 Carreras L M & Fano B, An R Acad Farm, 52, 1986,319.3 Hazimah A H , 1, Synthesis of some estragole analogues:2-The alkaloids of Breynia coronata, M Sc Thesis, Uni-versiti Pertanian Malaysia, Malaysia, 1990.4 Joshi B S, Gawad D H, Pelletier S W, Kartha G & Bhan-dary K, J Nat Prod, 49, 1986, 614, and references citedtherein.5 Snieckus V, in: The Alkaloids, Chemistry ind Physiol-ogy, Vol 14, edited by R H F Manske (Academic Press,New York), 1973, pp 425.6 Livant P D & Beutler J A, Tetrahedron,43, 1987, 1893.7 Arbain D, Birkbeck A A, Byrne L T, Sargent M V, Skel-ton B W & White A H, J Chern Soc Perkin Trans-1,1991,1863.8 Mulchandani N B & Hassarajani S A, Planta Med, 50,1984,104.9 Lajis N H, Guan 0 B, Sargent M V, Skelton B W &White A H, Awt J Chern,45, 1992, 1893.10 Iketubosin G 0 & Mathieson D W, J Pharm Pharmacol;15, 1964,810.11 Guan 0 B, The alkaloids from Breynia coronata, Bac ScThesis, Universiti Pertanian Malaysia, Malaysia, 1992.

Securinega alkaloids: Reinvestigation on the fresh leaves of Breynia coronate (Euphorbiaceae)

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Securinega alkaloids: Reinvestigation on the fresh leaves of Breynia coronate (Euphorbiaceae)

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