Chemical Investigation of Paederia foetidae(Rubiaceae)

Abstract

Paederia foetidae is familiar with common names Skunkvine; Stinkvine or Chinese Fever Vine 1. It is native to temperate and tropical Asia and has become naturalized in the Mascarenes, Melanesia, Polynesia and the Hawaiian Islands 2. Paederia foetida is known for the strong, sulfurous odour exudates when its leaves or stems are crushed or bruised. This is because the oil responsible for the smell and found primarily within the leaves, contains sulphur compounds, including largely dimethyl disulphide 3. Paederia species showed a lot of pharmacologic activities. Previously reported potential activities like antiinflammatory activity of the butanol fraction of a methanol extract of the defatted leaves of Paederia foetida 4. The analgesic effect of iridoid glycoside of Paederia scandens was studied by the formalin, acetic acid-induced writhing methods of mice 5. The antidiarrhoeal activity of the ethanol extract of Paederia foetida Linn. 6 , antinociceptive activity of paederosidic acid methyl ester (PAME) from the n-butanol fraction of Paederia scandens in mice 7 , antimicrobial activities 8 and antioxidant activity of phenolic content of Paederia foetida and Syzygium aqueum 9. The NMR spectra were recorded using a Bruker AMX-400 instrument. PTLC (20:20 cm) and TLC (20:5 cm) were carried out using Merck Silica gel 60 PF 254 on glass plates at a thickness of 0.5 mm. Spots on PTLC and TLC plates were visualized by spraying with 10 % vanillin in sulfuric acid followed by heating for 5 min at 110 ºC. Chemical investigation on the methanol extract of Paederia foetidae, using vacuum liquid chromatography resulted in the isolation of ethyl p-methoxy-trans-cinnamate. The structure was established by extensive spectral analysis (PMR, CMR, 2D NMR and MS etc.) and comparing with the published data. This is the first report of this compound from Rubiaceae family. plant was identified by Prof. Abul Hassan, Department of Botany, University of Dhaka, Bangladesh, where a voucher specimen (accession number DUSH 9600) has been deposited for further reference. The aerial plant part were cut into small pieces and then dried under sun for several days. The dried samples were then ground in coarse powder using high capacity grinding machine. This sample was preserved for future use marking in air tight container as it contains sulfurous odour. Extraction and isolation: The dried plant without roots (600 g) of Paederia foetidae was soaked in 1.5 L methanol for 7 days and filtered through a cotton plug followed by Whatman filter paper No. 1. Approximately 5.0 g of the crude extract was obtained through evaporation of solvent in vacuo. The crude extract was then subjected to VLC over silica gel using petroleum ether (60-800), ethyl acetate and methanol in order of increasing polarity. The VLC fraction eluted with 40 % ethyl acetate in petroleum ether was evaporated to dryness and the dried mass was subjected to sephadex column using 40 % chloroform in n-hexane, which afforded compound 1 (3.8 mg). Detection method Ethyl p-methoxy-trans-cinnamate (1): Fine colourless needles; ESIMS: m/z [M + H] + 207;

Full text

Paederia foetidae is familiar with common names
Skunkvine; Stinkvine or Chinese Fever Vine1. It is native to
temperate and tropical Asia and has become naturalized in the
Mascarenes, Melanesia, Polynesia and the Hawaiian Islands2.
Paederia foetida is known for the strong, sulfurous odour
exudates when its leaves or stems are crushed or bruised. This
is because the oil responsible for the smell and found primarily
within the leaves, contains sulphur compounds, including
largely dimethyl disulphide3. Paederia species showed a lot of
pharmacologic activities. Previously reported potential activities
like antiinflammatory activity of the butanol fraction of a
methanol extract of the defatted leaves of Paederia foetida4.
The analgesic effect of iridoid glycoside of Paederia scandens
was studied by the formalin, acetic acid-induced writhing
methods of mice5. The antidiarrhoeal activity of the ethanol
extract of Paederia foetida Linn.6, antinociceptive activity of
paederosidic acid methyl ester (PAME) from the n-butanol
fraction of Paederia scandens in mice7, antimicrobial activities8
and antioxidant activity of phenolic content of Paederia foetida
and Syzygium aqueum9.
The NMR spectra were recorded using a Bruker AMX-
400 instrument. PTLC (20:20 cm) and TLC (20:5 cm) were
carried out using Merck Silica gel 60 PF254 on glass plates at a
thickness of 0.5 mm. Spots on PTLC and TLC plates were
visualized by spraying with 10 % vanillin in sulfuric acid fol-
lowed by heating for 5 min at 110 ºC.
General procedures: Plant sample of Paederia foetidae
was collected from Rangpur, Bangladesh in April 2010. The
NOTE
Chemical Investigation of Paederia foetidae (Rubiaceae)
N. UDDIN1, M.K. HOSSAIN2, M.R. HAQUE2 and C.M. HASAN2,*
1Phytochemical Research Laboratory, Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Dhaka, Dhaka-1000,
Bangladesh
2Department of Pharmacy, Manarat International University, Mirpur-1, Dhaka-1216, Bangladesh
*Corresponding author: E-mail: cmhasan@gmail.com
(Received: 1 November 2011; Accepted: 31 August 2012) AJC-12068
Chemical investigation on the methanol extract of Paederia foetidae, using vacuum liquid chromatography resulted in the isolation of
ethyl p-methoxy-trans-cinnamate. The structure was established by extensive spectral analysis (PMR, CMR, 2D NMR and MS etc.) and
comparing with the published data. This is the first report of this compound from Rubiaceae family.
Key Words: Ethyl p-methoxy-trans-cinnamate, Rubiaceae, Paederia foetidae.
plant was identified by Prof. Abul Hassan, Department of
Botany, University of Dhaka, Bangladesh, where a voucher
specimen (accession number DUSH 9600) has been deposited
for further reference.
The aerial plant part were cut into small pieces and then
dried under sun for several days. The dried samples were then
ground in coarse powder using high capacity grinding
machine. This sample was preserved for future use marking
in air tight container as it contains sulfurous odour.
Extraction and isolation: The dried plant without roots
(600 g) of Paederia foetidae was soaked in 1.5 L methanol for
7 days and filtered through a cotton plug followed by Whatman
filter paper No. 1. Approximately 5.0 g of the crude extract
was obtained through evaporation of solvent in vacuo. The
crude extract was then subjected to VLC over silica gel using
petroleum ether (60-800), ethyl acetate and methanol in order
of increasing polarity. The VLC fraction eluted with 40 %
ethyl acetate in petroleum ether was evaporated to dryness
and the dried mass was subjected to sephadex column using
40 % chloroform in n-hexane, which afforded compound 1
(3.8 mg).
Detection method
Ethyl p-methoxy-trans-cinnamate (1): Fine colourless
needles; ESIMS: m/z [M + H]+ 207; 1H NMR (400 MHz,
CDCl3, Table-1); 13C NMR (100 MHz, CDCl3, Table-1).
Compound 1 was isolated from the methanol extract as
fine colorless needles, which appeared as a dark quenching
Asian Journal of Chemistry; Vol. 25, No. 2 (2013), 1163-1164
http://dx.doi.org/10.14233/ajchem.2013.12981

TABLE-1
SPECTRAL DATA OF 1 (IN CDCl3, TMS)
No 1H NMR 13C NMR HMBC
1 – 144.36 (s)
2 and 6 7.47 (d, J = 8.8 Hz) 129.70 (d) C-1, C-3
3 and 5 6.89 (d, J = 8.8 Hz) 114.32 (d) C-1’
4 - 161.38 (s)
1’ 7.63 (d, J = 16.0 Hz) 127.21 (d) C-6, C-3’
2’ 6.30 (d, J = 16.0 Hz) 115.76 (d) C-1’
3’ - 167.38 (s)
C-1” 4.24 (q, J = 7.2 Hz) 60.30 (t) C-3’, C-1”
C-2” 1.33 (t, J = 7.2 Hz) 14.37 (q) C-1”
-OCH3 3.83 55.39 (q) C-4
spot on TLC plate under UV light at 254 nm. The compound 1
gave a pseudo mol. ion at 207 (m+ + H) corresponding to mol.
wt 206 and formula C12H14O3. The structure was established
as ethyl p-methoxy-trans-cinnamate by comparing the spectral
data (1H NMR) with those reported for this compound10,11. The
structure was further substantiated by NOESY, COSY, HSQC
and HMBC experiments. This is the first report of this compound
from Rubiaceae family.
In 1H NMR (Table-1) spectra the methoxy group appeared
as a singlet at δ 3.83. Two 2H doublets were observed for four
aromatic protons at δ 6.89 and δ 7.47. The splitting pattern
and coupling constants (J = 8.8 Hz) of the aromatic protons
indicated the presence of a 1,4-disubstituted benzene ring. It
also showed a 2H quartet at δ 4.24 and a three methyl triplet at
δ 1.33 for a primary methyl group. The trans-olefinic protons,
H-1' and H-2' appeared as doublets (J = 16 Hz) at δ 7.63 and
6.30, respectively. The relatively low field resonance for H-1'
could be explained by its β-position to the carbonyl group.
13C NMR (Table-1) displayed 12 carbons in the skeleton. To
our knowledge there is no report of 13C NMR of this compound.
HMBC experiments showed the connectivity of CH2 proton
at δ 4.24 with CO carbon (δC 167.38) of the ester group.
Fig. 1. Ethyl p-methoxy-trans-cinnamate
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