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Alkaloids from Piper sarmentosum andPiper nigrumG.C.L. Ee a , C.M. Lim a , C.K. Lim b , M. Rahmani a , K. Shaari a &C.F.J. Bong ca Department of Chemistry, Faculty of Science , Universiti PutraMalaysia , 43400, Serdang, Selangor, Malaysiab Faculty of Engineering & Science , Universiti Tunku AbdulRahman, Setapak , 53300, Kuala Lumpur, Malaysiac Department of Crop Science, Faculty of Agriculture & FoodSciences , Universiti Putra Malaysia Bintulu Campus , 97008,Bintulu, Sarawak, MalaysiaPublished online: 22 Sep 2010.

To cite this article: G.C.L. Ee , C.M. Lim , C.K. Lim , M. Rahmani , K. Shaari & C.F.J. Bong (2009)Alkaloids from Piper sarmentosum and Piper nigrum , Natural Product Research: Formerly NaturalProduct Letters, 23:15, 1416-1423, DOI: 10.1080/14786410902757998

To link to this article: http://dx.doi.org/10.1080/14786410902757998

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Natural Product ResearchVol. 23, No. 15, 15 October 2009, 1416–1423

Alkaloids from Piper sarmentosum and Piper nigrum

G.C.L. Eea*, C.M. Lima, C.K. Limb, M. Rahmania, K. Shaaria and C.F.J. Bongc

aDepartment of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400, Serdang,Selangor, Malaysia; bFaculty of Engineering & Science, Universiti Tunku Abdul Rahman, Setapak,53300, Kuala Lumpur, Malaysia; cDepartment of Crop Science, Faculty of Agriculture & FoodSciences, Universiti Putra Malaysia Bintulu Campus, 97008, Bintulu, Sarawak, Malaysia

(Received 9 September 2008; final version received 3 November 2008)

Detailed chemical studies on the roots of Piper sarmentosum and Piper nigrumhave resulted in several alkaloids. The roots of P. sarmentosum gave a newaromatic compound, 1-nitrosoimino-2,4,5-trimethoxybenzene (1). Piper nigrumroots gave pellitorine (2), (E)-1-[30,40-(methylenedioxy)cinnamoyl]piperidine (3),2,4-tetradecadienoic acid isobutyl amide (4), piperine (5), sylvamide (6),cepharadione A (7), piperolactam D (8) and paprazine (9). Structuralelucidation of these compounds was achieved through NMR and MStechniques. Cytotoxic activity screening of the plant extracts indicated someactivity.

Keywords: Piper nigrum; Piper sarmentosum; alkaloids; cytotoxic

1. Introduction

The genus Piper is from the Piperaceae family. The Piperaceae family is a source ofmany biologically active secondary metabolites which have great potential for medicinaluses. Many Piper species have a wide array of natural compounds, which includealkaloids and amides (Scott et al., 2005). It is recorded that Piper nigrum has biologicalactivities such as CNS stimulant, analgaesic, antipyretic and antifeedent activities(Miyakado, Nakayama, & Yoshioka, 1979). Meanwhile, Piper sarmentosum possesses avariety of medicinal properties. The leaves of P. sarmentosum have been used to treatmalaria, coughs and colds and even toothache. Previous work on P. sarmentosumhas reported the presence of amides which possess antituberculosis and antiplasmodialactivities (Rukachaisirikul et al., 2004). Recently, two alkaloids from the samespecies have been reported to show antifungal activities (Tuntiwachwuttikul, Phansa,On, & Taylor, 2006). This article reports the isolation of the new aromaticimino compound from P. sarmentosum and the cytotoxic activities of P. sarmentosumand P. nigrum.

*Corresponding author. Email: gwen@fsas.upm.edu.my

ISSN 1478–6419 print/ISSN 1029–2349 online

� 2009 Taylor & Francis

DOI: 10.1080/14786410902757998

http://www.informaworld.com

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2. Experimental

2.1. Plant material

The roots of P. nigrum were collected from Sri Aman, Sarawak, Malaysia. The aerial parts

of P. sarmentosum were obtained from Bintulu, Sarawak, Malaysia.

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N

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2"

3"

4"

5"

1

2

3

4

5

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6'

NH

OH

OH

H2C

O

4'

3'2'

1'

1

2

345

10

6-9

O

O

NCH3

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H

H

H

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H

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7

8

910

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11c

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2'1'

7'

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7

1

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45

6

NHN

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OCH3

OCH3

H3CO

(1)

NH

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3'

4'

2'1'

1

2

3

4

5

6

7

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9

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(2)

O

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N

2'

1'

3'

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6'

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21

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3"

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6"

(3)

CH2 NH

O

12

3

4

5

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714 1'2'

3'

4'

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8-13

(4)

(5)

(6)

(7)

(8)

(9)

1

2

3

45

6

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2.2. General

Infrared spectra were measured in NaCl pellet on a Perkin–Elmer FTIR Spectrum BXspectrometer. EIMS were recorded on a Shidmazu GCMS-QP5050A spectrometer.NMR spectra were obtained using Unity INOVA 500MHz NMR/JEOL 400MHzFTNMR spectrometer using tetramethylsilane (TMS) as internal standard. Ultravioletspectra were recorded in CHCl3 on a Shidmazu UV-160A, UV-visible recordingspectrophotometer.

2.3. Extraction and isolation

The dried ground sample of the aerial parts of P. sarmentosum underwent hexanesoxhlet extraction. This gave 47.4 g of hexane extract. The extract was purified viasilica gel column chromatography using hexane, hexane-chloroform, chloroform,chloroform-ethyl acetate, ethyl acetate and ethyl acetate-methanol as eluting solvents.This process resulted in the isolation of a new aromatic compound, 1-nitrosoimino-2,4,5-trimethoxybenzene (1).

The dry-powdered roots of P. nigrum (4.8 kg) were extracted repeatedly for morethan 48 h with petroleum ether, chloroform, and ethyl acetate, followed by ethanol. Allthe extracts were dried in vacuo to obtain crude extracts. The ethanol extract was thenadded to a large quantity of 5% aqueous hydrochloric acid. The acidic solution wasthen filtered through kieselghur to remove non-alkaloidal substances. The filtrate wasthen basified with concentrated ammonia solution to pH 10. The liberated alkaloidswere extracted exhaustively with chloroform. The chloroform extract was then washedwith distilled water and dried over anhydrous sodium sulphate. The acid-base treatedethanol extract was obtained by removing the solvent under reduced pressure togive an oil (0.53 g). The crude extract was chromatographed over silica gel (120–230mesh) column and fractions were collected in 100mL aliquots. This resultedin pellitorine (2), (E)-1-[30,40-(methylenedioxy)cinnamoyl]piperidine (3) and 2,4-tetra-decadienoic acid isobutyl amide (4). Purification and isolation of the petroleum etherextract resulted in piperine (5) while the ethyl acetate extracts furnished sylvamide (6).Meanwhile, the chloroform extract gave cepharadione A (7), piperolactam D (8) andpaprazine (9).

Pellitorine (2). White crystals with m.p. 60–62�C (Lit. 69�C (Rosario, Silva, & Parente,1996)). UV (CHCl3) �max nm (log "): 292(1.87), 236(0.48), 212(0.53), 264(0.27) and220(0.31). IR �max cm

�1 (NaCl): 3300 (N–H group), 2926, 2864, 1656 (C¼O), 1624, 1550,1460, 1368, 1260, 1160 and 994. EIMS m/z (rel. int.): 223(43), 208(10), 180(7), 166(8),151(100), 110(12), 96(55), 81(50), 67(21) and 53(18). NMR data are in agreement withpublished data (Rosario et al., 1996).

(E)-1-[30,40-[Methylenedioxycinnamoyl] piperidine (3). White crystals with m.p. 74–76�C(Lit. 83�C (Schobert, Siegfried, & Gordon, 2001)). UV (CHCl3) �max nm (log "): 325(2.46),235(0.82), 397(0.01) and 251(0.60). IR �max cm�1 (NaCl): 3460, 2934, 2858, 1642, 1598,1494, 1444, 1354, 1248, 1134, 1034, 978, 930 and 810. EIMS m/z (rel. int.): 259(57),175(73), 148(30), 145(100), 138(17), 117(33), 89(66), 84(86) and 63(31). NMR data are inagreement with published data (Schobert et al., 2001).

2,4-Tetradecadienoic acid isobutyl amide (4). Oily yellow crystals. The melting point ofthis compound was 88–90�C (Lit. 90�C (Greger, Grenz, & Bohlmann, 1981)). UV �max nm

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(Chloroform, log "): 240(1.2) and 214(1.4). IR �max (cm�1, KBr disc): 3250 (NH), 2950,1655, 1554, 1410, 1340, 1255 and 988. MS (m/z rel. int.): m/z 279 [Mþ] (0.7%), 259(0.4),235(9), 223(36), 208(16), 192(19), 180(10), 164(19), 151(100), 138(17), 123(28), 110(18),96(65), 81(79), 67(32) and 55(27). NMR data are in agreement with published data (Gregeret al., 1981).

Piperine (5). Yellow crystals which melts at 126–128�C (Lit. 128–129�C (Parmar et al.,1998)). UV �max nm (Chloroform, log "): 382(2.96), 325(4.00), 306(4.00), 239(0.25),366(2.78) and 323(3.96). IR �max (cm�1, KBr disc): 2998, 1638 (C¼O), 1490 (C–O). MS(m/z, rel. int.): m/z 285 [Mþ] (26.54%), 201(54), 173(34), 159(4.5), 143(30), 137(9.5),115(100), 100(10) and 84(37). NMR data are in agreement with published data (Parmaret al., 1998).

Sylvamide (6). Colourless shiny crystals with melting point of 142–144�C (Lit. 143–144�C(Banerjit, Sarkar, Datta, Sengupta, & Abraham, 2002)). UV �max nm (Methanol, log "):282(0.44), 256(0.09), 258(0.18), 243(0.30) and 224(0.08). IR �max (cm�1, KBr disc): 3288(N), 2930, 1670, 1562, 1462, 1334, 1274, 1162 and 984. MS (m/z, rel. int.): m/z 257 [Mþ](0.15%), 158(51), 157(100), 128(8), 114(2), 101(7), 84(24), 83(27) and 57(50). 1H NMR,� (400Hz, CD3OD): 6.83 (1H, dd, J¼ 15.0, 4.6Hz, H-3), 6.15 (1H, d, J¼ 15.0, H-2), 4.07(1H, s, H-4), 3.49 (1H, s, H-5), 3.05 (2H, d, J¼ 6.4, H-10), 1.76 (1H, m, H-20), 1.56 (2H, m,H-6), 1.31 (6H, m, H-7, H-8 and H-9), 0.90 (1H, d, J¼ 6.4, H-30 and H-40). 13C NMR,� (100MHz, CD3OD): 168.47 (C-1), 144.42 (C-3), 125.10 (C-2), 75.56 (C-4), 75.41 (C-5),48.57 (C-10), 33.72 (C-6), 33.03 (C-8), 29.70 (C-20), 26.57 (C-7), 23.69 (C-9), 20.50 (C-30 andC-40) and 14.39 (C-10).

Cepharadione A (7). Orange needle crystals with melting point 351–353�C (Lit. 350�C(Akasu, Itokawa, & Fujita, 1990)). UV �max nm (MeOH, log "): 219(4.6), 238(4.2),238(4.2), 256(4.2), 279(4.2), 290(4.2), 303(4.24), 315(4.3) and 439(4.3). IR �max (cm

�1, KBrdisc): 2950, 1690, 1554, 1412, 1330, 1250. MS (m/z, rel. int.): m/z 305 [Mþ] (70.20%),277(100), 260(18.19), 248(16.35), 219.10(8.96), 190.15(11.08), 163.05(34.83), 150(10.78),138(49.18), 123(10.86), 110(4.77) and 95.45(32.07). NMR data are in agreement withpublished data (Akasu et al., 1990).

Piperolactam D (8). Yellow crystals with melting point 228–230�C (Lit. 226–227�C(Sanjay, Chaturvedi, & Mulchandani, 1990)). UV �max nm (Chloroform, log "):235(4.83), 266(4.15), 294(4.81), 329(4.27), 362(4.33) and 3.81(4.30). IR �max (cm�1,KBr disc): 3262 (broad OH), 2924 (NH), 1678 (C¼O), 1610, 1482, 1460, 1400, 1316,1196, 1152, 1120 and 1080. MS (m/z, rel. int.): m/z 295 [Mþ] (100%), 279(23.44),252(46.01), 234(15.19), 209(20.68), 181(8.12), 153(24.79), 126(22.08), 118(26.75),104(9.64), 90(30.36) and 76(37.29). NMR data are in agreement with published data(Sanjay et al., 1990).

Paprazine (9). Amorphous powder with melting point 250–251�C (Lit. 253–254�C (Ikuo,Tamihide, Hiroe, Kazuhito, & Hidetoshi, 1991)). UV �max nm (Chloroform, log "):310(4.00). IR �max (cm�1, KBr disc): 3432 (NH), 3308 (broad OH), 1666 (C¼O), 1174,1106, 1052 (C–O). MS (m/z, rel. int.): m/z 283 [Mþ] (9.87%), 164(70), 147(100), 120(56),107(13), 91(19), 77(8) and 65(13). 1H NMR, � (400MHz, Acetone-d6): 9.06 (1H, s, NH),8.40 (1H, s, OH), 7.42 (1H, d, J¼ 15.6Hz, H-80), 7.37 (2H, d, J¼ 8.2Hz, H-50 and H-30),7.02 (2H, d, J¼ 8.2Hz, H-3 and H-5), 6.81 (2H, d, J¼ 8.2Hz, H-20 and H-60), 6.71 (2H, d,J¼ 8.2Hz, H-2 and H-6), 3.44 (2H, t, J¼ 7.3, 7.4 Hz, H-7), 2.71 (2H, m, H-8).

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13C NMR, � (100 MHz, Acetone-d6): 166.6 (C¼O), 159.8 (C-4), 156.1 (C-40), 140.1 (C-80),130.9 (C-1), 130.4 (C-3 and C-5), 130.1 (C-30 and C-50), 127.6 (C-10), 119.5 (C-70), 116.5(C-20 and C-60), 115.9 (C-2 and C-6), 41.9 (C-8), 35.7 (C-7).

2.4. Cytotoxic assay

The stock solution of the sample (compound) was prepared at a concentration of5mgmL�1 in dimethylsulphoxide (DMSO). Serial dilution of the stock solution in thegrowth medium provided seven sample solutions at concentrations of 2.5, 5.0, 7.5, 10.0,20.0, 30.0 and 40.0 mgmL�1. HL60 and HeLa cell lines were obtained from theNational Cancer Institute in Maryland, USA. Cells were grown in a 96-well microlitreplate by filling each well with 100 mL of stock culture (1� 105 cellsmL�1) and incubatedat 37�C for 24 h. Growth medium was removed from the wells and each well was thentreated with 100mL of varying concentrations of sample solution. Controls were madecontaining only untreated cell populations in 100 mL of growth medium. The assay foreach concentration of sample was performed in triplicate and the culture plate wasincubated for 3 days at 37�C, 5% CO2 and 90% humidity. After 3 days, 10 mL of theMTT reagent (0.5mgmL�1) (Roche Diagnostics, USA) was added to each well.The plate was then incubated further for 4 h at 37�C with 5% CO2. After that, 100 mLof the solubilisation solution was added to each well and the plate was allowedto stand overnight in the incubator at 37�C with 5% CO2. Cell viability wasmeasured using an ELISA spectrophotometer (ELx 800) at a wavelength of 550 nm.The inhibitory concentration that killed cells by 50% (IC50) was determinedfrom absorbance (OD) versus concentration curve (Rahmat, Rosli, Zain, Endrini,& Sani, 2002).

3. Results and discussion

1-nitrosoimino-2,4,5-trimethoxybenzene (1) was isolated from the hexane extract ofP. sarmentosum as white powder with a melting point of 90–91�C. The CIMS spectrumgave m/z [Mþ1] 225, which corresponded to the molecular formula C10H12N2O4. TheIR-spectrum indicated the presence of C¼N stretching absorption band at 1650 cm�1.The UV spectrum gave a maximum absorption at 340.0 nm.

The 1H NMR spectrum revealed three singlet proton signals at � 6.50, � 7.33 and� 10.32. The two signals at � 6.50 and � 7.33 were due to two protons attached to a benzenering. These protons were assigned to H-3 and H-6, respectively. Another proton signallocated at � 10.32 (H-10), at the down-field region of the NMR spectrum was assignedto the proton of the nitrosoimino group. Three methoxy protons were observed at � 3.88,� 3.93 and � 3.98.

The 13C NMR spectrum gave a total carbon count of 10 with three methinecarbons, four quaternary carbons and three methyl carbons as indicated by analysis ofDEPT data. The assignment of the carbon peaks to their respective protons was carriedout by HMQC analysis. From the HMQC spectrum, it was seen that the carbon peak at� 188.0 was correlated to the proton peak at � 10.32; a significant peak to confirmthe existence of a CHN group in the compound. Meanwhile, the aromatic proton at � 6.50was coupled to the carbon at � 95.0 and the carbon at � 109.0 was correlated to the protonat � 7.33. However, no correlations were observed in the COSY spectrum. Hence, the

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position of the proton at � 6.50 (H-2) was not adjacent to the proton at � 7.33 (H-4) in thecompound (Table 1).

The HMBC spectrum gave a correlation between the CHN carbon at � 188.02 and theproton at � 7.33 (H-6) via a 3J-coupling (Figure 1). The correlation of the proton at � 7.33(H-6) with the carbon at � 158.0 (C-2) and � 155 (C-4) via a 3J correlation and with � 143.0(C-5) via a 2J-coupling and with � 117 (C-1) is sufficient evidence for the placement of theproton at C-6. Meanwhile, the signal at � 10.32 gave HMBC correlations with � 117 (C-1)and � 109.0 (C-6). Hence it was decided that the CHN carbon is located at C-1. It was alsoobserved that the proton signal at � 6.50 (H-3) gave correlations with � 117.0 (C-1), � 158.0(C-2) and � 155 (C-4) and � 143.0 (C-5) via 3J and 2J couplings. Thus, it was concluded thatthe singlet at � 6.50 has to be located at C-3. The HMBC experiment also gave correlationsbetween � 3.93 (2-OMe) and � 158.0 (C-2), � 3.98 (4-OMe) and � 155.0 (C-4), and � 3.88(5-OMe) with � 143.0 (C-5). Hence, the positions of the three methoxy groups wereassigned with two methoxyls adjacent to each other at C-4 and C-5. Therefore, thiscompound was assigned as 1-nitrosoimino-2,4,5-trimethoxybenzene (1) (Figure 1). This is

OCH3

OCH3

H3CO

H

H

C

H N N

O

1

35

4

2

6

Figure 1. HMBC correlations for 1.

Table 1. NMR data for 1-nitrosoimino-2,4,5-trimethoxybenzene (1).

Position 1H NMR, � 13C-NMR, � HMBC

1 117.02 158.03 6.50 (1H, s,) 95.0 117.0 (C-1) (3J), 158.0 (C-2) (2J ),

155.0 (C-4) (2J ), 143.0 (C-5) (3J )4 155.05 143.06 7.33 (1H, s) 109.0 158.0 (C-2) (3J), 155.0 (C-4) (3J),

143.0 (C-5) (2J), 188.0 (1-CHN) (3J )1-CHN 10.32 (1H, s) 188.0 117.0 (C-1) (2J), 109.0 (C-6) (2J )2-OCH3 3.93 (3H, s) 56.2 158.0 (C-2) (3J)4-OCH3 3.98 (3H, s) 56.3 155.0 (C-4) (3J)5-OCH3 3.88 (3H, s) 56.1 143.0 (C-5) (3J)

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a new compound and was not reported by Tuntiwachwuttikul et al. (2006) in their paperon P. sarmentosum.

The structures of the other eight alkaloids were determined by comparisons of spectraldata with that of published data – pellitorine (2) (Rosario et al., 1996) (E)-1-[30,40-[methylenedioxycinnamoyl]piperidine (3) (Schobert et al., 2001), 2,4-tetradecadienoicacid isobutyl amide (4) (Greger et al., 1981), piperine (5) (Parmar et al., 1998), sylvamide(6) (Banerjit et al., 2002), cepharadione A (7) (Akasu et al., 1990), piperolactam D (8)(Sanjay et al., 1974) and paprazine (9) (Ikuo et al., 1991).

The extracts of P. nigrum and P. sarmentosum were tested for cytotoxic activities.The extracts of P. nigrum were tested on HL60 (human promyelocytic leukaemia cells).The petroleum ether and chloroform extracts were bioactive against the HL60 cell linewith a high inhibitory concentration of 30 mgmL�1. The ethyl acetate extract gave noactivity. The petroleum ether extract gave an IC50 value of 11.2 mgmL�1 and the IC50

value of the chloroform extract was 9.8mgmL�1. Meanwhile, the crude extracts ofP. sarmentosum were tested on HeLa cell line (human epithelial cells derived fromcervical cancer cells). The hexane extract gave an IC50 value of 11.6mgmL�1.Meanwhile, the hexane extract of P. sarmentosum showed activity against the MCF-7cell line with an IC50 value of 14.4mgmL�1, while the ethyl acetate gave an even lowerIC50 value of 9.8mgmL�1. Pellitorine, on the other hand, was found to be extremelycytotoxic towards the MCF-7 cell line with an IC50 value of 1.8 mgmL�1, but slightlyless toxic against the HeLa cell line with an IC50 value of 13 mgmL�1. The goodactivity of the petroleum ether extract of P. nigrum against the HL60 cell line could bedue to the presence of piperine, while that of the chloroform extract could be due tothe mixture of alkaloids which are cepharadione, piperolactam and paprazine.Meanwhile, the hexane extract of P. sarmentosum gave an equally good activity forthe HeLa and MCF-7, and there could be contribution by the imino compound 1-nitrosoimino-2,4,5-trimethoxybenzene (1).

Acknowledgements

The authors wish to thank Dr Jegak Uli for collection of plant samples, Mr Johadi Iskandar forrecording NMR spectra and the FRGS research grant for financial support.

References

Akasu, M., Itokawa, H., & Fujita, M. (1990). Four new fluorescent components isolated from thecallus tissue of Stephania cepharantha. Tetrahedron Letters, 10, 3609–3612.

Banerjit, A., Sarkar, M., Datta, R., Sengupta, P., & Abraham, K. (2002). Amides from Piperbrachystachyum and Piper retrofractum. Phytochemistry, 59, 897–901.

Greger, H., Grenz, M., & Bohlmann, F. (1981). Amides from Achillea species and Leucocyclusformosus. Phytochemistry, 11, 2579–2581.

Ikuo, M., Tamihide, M., Hiroe, K., Kazuhito, W., & Hidetoshi, Y. (1991). Analysis andpharmacotoxicity of feruloyltyramine as a new constituent and p-coumaroyltyramine in

Cannabis sativa L. Pharmacology Biochemistry and Behaviour, 40, 465–469.Miyakado, M., Nakayama, I., & Yoshioka, H. (1979). The Piperaceae amides. Part III. Insecticidal

joint action of pipercide and co-occurring compounds isolated from Piper nigrum L.Agricultural and Biological Chemistry, 44(7), 1701–1703.

Parmar, V.S., Jain, S.C., Gupta, S., Talwar, S., Rajawanshi, U.K., Kumar, R., et al. (1998).Polyphenols and alkaloids from Piper species. Phytochemistry, 49(4), 1069–1078.

1422 G.C.L. Ee et al.

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Uni

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Rahmat, A., Rosli, R., Zain, W.N.I.W.M., Endrini, S., & Sani, H.A. (2002). Antiproliferativeactivity of pure lycopene compared to both extracted lycopene and juices from watermelon(Citrullus vulgaris) and papaya (Carica papaya) on human breast and liver cancer cell lines.Journal of Medical Science, 2, 55–58.

Rosario, S.L., Silva, A.J., & Parente, J.P. (1996). Alkamides from Cissampelos glaberrima. PlantaMedica, 62, 376–377.

Rukachaisirikul, T., Siriwattanakit, P., Sukcharoenphol, K., Wongvein, C., Ruttanawang, P.,

Wongwattanavuch, P., et al. (2004). Chemical constituents and bioactivity of Pipersarmentosum. Journal of Ethnopharmacology, 93, 173–176.

Sanjay, D.J., Chatuvedi, R., & Mulchandani, N.B. (1990). Piperolactam D, a new aristolactam from

Indian Piper species. Journal of Natural Products, 53, 496–497.Schobert, R., Siegfried, S., & Gordon, G.J. (2001). Three-component synthesis of (E)-�,

�-unsaturated amides of the piperine family. Journal of Chemical Society, Perkin

Transactions, I, 2393–2397.Scott, I.M., Puniani, E., Jensen, H., Livesey, J.F., Poveda, L., Vindas, P.S., et al. (2005). Analysis of

Piperaceae germplasm by HPLC and LCMS: A method for isolating and identifyingunsaturated amides from Piper spp extracts. Journal of Agricultural and Food Chemistry, 53,

1907–1913.Tuntiwachwuttikul, P., Phansa, P., On, Y.P., & Taylor, W.C. (2006). Chemical constituents of the

roots of Piper sarmentosum. Chemical Pharmaceutical Bulletin, 54, 149–151.

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