The major alkaloid of Cyclea laxiflora Miers. was isolated and identified as dicentrine from its spectral and physical

data

Ismail, Norhayati

Lajis, Md Nordin

Samadi, Zainuddin

Universiti Putra Malaysia Institutional Repository

PERTANIKA14(3), 353-354 (1991)COMMUNICATION VDicentrine: the Major Alkaloid of Cyclea laxiflara Miers.Key words: Cyclea laxiflora, dicentrine, alkaloid.ABSTRAKSebatian alkaloid bagiCyclea laxiflora Miers. telah diasingkan dan dikenalpasti sebagai disentrina berdasarkan dataspektrum dan jizik.ABSTRACTThe major alkaloid ofCyclea laxiflora Miers. was isolated and identified as dicentrinefrom its spectral and physicaldata.INTRODUCTIONCyclea laxiflora Miers (Menispermaceae) is s slenderwoody climber found in the limestone hills ofLangkawi Island located at the northern tip ofPeninsular Malaysia. The tubers of this plant aresold by dealers for traditional medicine; it is claimedthat these roots are a remedy for sinus trouble andfever (Burkill, 1936). As part of our interest in thechemical constituents of medicinal plants, we havenow investigated the alkaloid of this plant.MATERIALS AND METHODSThe roots of C. laxiflora were collected from thelimestone hill nearTanjungAmon Langkawi Island,off Peninsular Malaysia. A voucher specimen NoUPM 4666 has been deposited at the herbarium ofthe Biology Department, Universiti PertanianMalaysia.Melting pointswere determined on a Kofler hotstage and are uncorrected. Infrared and ultravioletspectra were recorded on Beckmann Acculab 3 andHitachi 200-2 spectrometers, respectively. IH andI3C NMR spectra were measured at 80 and 20.1MHz, respectively on a Bruker WP 80 spectrometer.Mass spectra were recorded on AEI-MS 12 instru-ment at 70 eV.ExtractionThe fresh roots were cleaned to remove soil, gratedto small pieces of roughly 1 x 0.5 mm cross-sectionand steeped in methanol for 24hours. The methanolextractwas then drained offand fresh methanol wasintroduced. This procedure was repeated until thefinal extract gave a negative Meyers test for alkaloids.The methanol extracts were combined andevaporated in vacuo to give 109 of a brown gumwhich was partitioned between chloroform and 1M H 2S04, The aqueous acidic solution was thenbasified with Na2C03 and extracted withchloroform to give 4 g of crude base.Isolation ofDicentrineThe crude base was subjected to columnchromatography using silica gel (mesh 230-400).The column was elutedwith chloroform/methanolmixtures (5% increment of methanol on eachaddition of500 ml ofeluent until a 35% methanolconcentration was reached, followed by 10%increments ofmethanol from then on). Aset of55fractions (each 50 ml) was collected; the majorconstituent was found to be present in fractions 13,14 and 15. These fractions were combined andrecrystallized from methanol to give 500 mg ofcolourless prisms, m.p. 168-169°C (lit. 169°C,Southon and Buckingham, 1989)."'max MeOH: 306 nm(log £ 4.20),284 nm (log £4.18) ,220 nm (log £ 4.52), (Craig and Roy 1965);urn.. (CHCI3 film): 2980-2920, 1615, 1595, 1520,1470, 1400, 1l05, 870 cm-I: IH NMR (80 MHz,CDCI3) 0: 7.67 (s, IH), 6.78 (s, IH), 6.51 (s,IH),6.00 (dd, 1l,7, 1.3 MHz, 2H), 3.92(s, 6H 2 xOCH3) , 3.21-2.93(m, 5H), 2.79-2.61(m, 2H),2.55(s, 3H, N-CH3); 13C NMR (20.1 MHz, CDCI3)0:148.2 (C-9) , 147.6 (C-2) , 146.5 (C-IO, 141.7(C-l), 128.3 (C-7a), 126.5 (C-llc), 126.3 (C-llb),123.5 (C-lla) , 1l0.6 (C-ll), 106.6 (C-3) , 62.3(C-6a, 53.5 (C-5), 43.83 (N-CH3), 34.2 (C-7) ,29.2 (C-4); MS m/z(%): 339(70), 338(100),NORDIN H. LAJIS, ZAINUDIN SAMADI AND NORHAYATI ISMAIL322(25),307(20),296(30),265(20).RESULTS AND DISCUSSIONThe major alkaloid isolated from the fresh root ofC. laxijlora crystallized as a colourless prism (m.p.168-169°) from methanol after purification of thecrude basic fraction by column and thin layerchromatography. The mass spectrum gave M+ atm/z 339 consistent with the molecular formulaC20H21NO4' The proton NMR spectrum showedthree one-proton singlet peaks at 0 7.67,6.78 and6.51 corresponding to H-ll, H-8 and H-3respectively of an aporphine alkaloid. The twoprotons double-doublet at 06.0 is consistent with amethylenedioxy substituent on Cl - C2 and a six-proton singlet peak at 0 3.92 attributed to twomethoxyl groups on e-9 and e-10. The Nmethylprotons appeared at 0 2.55. Other signals whichappeared as multipiers at 0 3.21 to 2.93 and 2.79 to2.61 ppm integrated for five protons and twoprotons, respectively (Lu et at. 1972). Theassignment of the structure was further supportedby the I3C NMR spectrum which agreed with thereported value (Marsaioli et al. 1979; Hara et al.1986) for dicentrine (1).Previously, berbamine had been isolated fromC. barbata (Dahmen et al. 1977) and the seven Cycleaspecies used in Chinese traditional medicine havealso been found to contain bisbenzylisoquinolines(Zhu et al. 1983). Aporphine alkaloids do notappear to have been found in Cycleaspecies before.CHO~3 OCH3( 1)ACKNOWLDEGEMENTSThe authors thank the International Foundationfor Science (IFS) and the National Council forScientific Research and Development for financialsupportand the Network for Biologically ImportantNatural Products for some spectra. The assistance'of Mr. S. Anthonysamy of Biology Department,UPM in plant identification is duly acknowledged.NORDIN H. LAJIS,ZAINUDIN SAMADI AND*NORHAYATI ISMAILDepartment ofChemistryUniversiti Pertanian Malaysia43400 UPM, Serdang,Selangor Darnl Ehsan, Malaysia.*School ofPharmaceutical SciencesUniversiti Sains Malaysia11800 Minden, Pulau Pinang.REFERENCESBURKILL, I.H. 1936. A Dictionary oftheEconomic Productsofthe Malay Peninsula, 2vols. CrownAgents for theColonies, London. (reprint 1966, Ministry ofAgriculture anp Cooperatives, Kuala Lumpur).CRAIG, ].C. and S.K. Roy. 1965. Optical RotatoryDispersion and Absolute Configuration II,Aporphine Alkaloids. Tetrahedron 21 :395.DAHMEN, K., P. PAcHALYand F. ZYMALKOWSKI. 1977.Alkaloids from the Thai Drug, Krung Kha Moa,(Cycl.ea barbata, Menispermaceae).V. Isolation andStructural Elucidation of FurtherBisbenzylisoquinoline Alkaloids. Arch. Pharm.310:95.HARA, H., F. HAsHIMOTO, O. HOSHINO and B. UMEZAWA.1986. Studies on Tetrahydroisoquinolines XXVIII.Syntheses of (±)-Nmethyllaurotetanine, (±)-cassythicine, (±) -9-hydroxy-l ,2,3,10-tetramethoxyaporphine, (±)-dicentrine and (±)_.thalicsimidine. Chern. Pharm. Bull. 34:1946-1949.Lu, ST., SJ. WANG, P.H. LAI, C.M. LING and L.C. LIN.1972. Alkaloids ofFormosan Lauraceous Plants.XV: Alkaloids ofLindera oldhamii, Heins!. YakugakuZasshi. 92: 910-917 (CA:77, 101949m).MARsAlOLl, A.]., F. A. M. RErs, A. F. MAGALHAES andE.A. RUVEDA. 1979. I3C NMR Analysis ofAporphine Alkaloids. Phytochemistry 18: 535-545.SOUTHON, I.W. and]. BUCKINGHAM. 1989. Dictionary ofAlkaloids. London: Chapman and Hall. 333p.ZHU, Z., Y. FENG, L. HE and Y. WANG. 1983. Study onUtilization of Medicinal Plant Resources of theGenus CycleaofMenispermaceae in China. Yaoxuexuebau. 18:535-540 (CA: 100, 25973r).(Received 2 May, 1991)354 PERTANlKAVOL. 14NO.3, 1991

Dicentrine: The Major Alkaloid of Cyclea laxiflara Miers

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Dicentrine: The Major Alkaloid of Cyclea laxiflara Miers

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