S-substituted cysteine derivatives and thiosulfinate formation in Petiveria alliacea - Part II

Article abstract of DOI:10.1016/S0031-9422(02)00328-X

Three cysteine derivatives, (R)-S-(2-hydroxyethyl)cysteine, together with (R_SR_C)- and (S_SR_C)-S-(2-hydroxyethyl)cysteine sulfoxides, have been isolated from the roots of Petiveria alliacea. Furthermore, three add

Full text of DOI:10.1016/S0031-9422(02)00328-X

Phytochemistry 61 (2002) 675–680
www.elsevier.com/locate/phytochem
S-Substituted cysteine derivatives and thiosulfinate formation
in Petiveria alliacea—part II
1
Roman Kubec , Seokwon Kim, Rabi A.Musah*
Department of Chemistry, State University of New York at Albany, Albany, NY, 12222, USA
Received 19 March 2002; received in revised form 12 July 2002
Abstract
Three cysteine derivatives, (R)-S-(2-hydroxyethyl)cysteine, together with (R R )- and (S R )-S-(2-hydroxyethyl)cysteine sulf-
oxides, have been isolated from the roots of Petiveria alliacea.Furthermore, three additional amino acids, S-methyl-, S-ethyl-, and
S
C
S C
ꢀ1
S-propylcysteine derivatives, were detected.They were present only in trace amounts ( <3 mg g fr.wt), precluding determination of
their absolute configurations and oxidation states.In addition, four thiosulfinates, S-(2-hydroxyethyl) (2-hydroxyethane)-, S-(2-hydro-
xyethyl) phenylmethane-, S-benzyl (2-hydroxyethane)- and S-benzyl phenylmethanethiosulfinates, have been found in a homogenate of
the roots.The formation pathways of various benzyl/phenyl-containing compounds previously found in the plant were also discussed.
#
2002 Elsevier Science Ltd.All rights reserved.
Keywords: Petiveria alliacea; Phytolaccaceae; S-(2-Hydroxyethyl)cysteine; S-(2-Hydroxyethyl)cysteine sulfoxide; 6-Hydroxyethiin; Petiveriin; Peti-
vericin; Thiosulfinate
1
. Introduction
acid, benzyl benzoate) (Adegosan, 1974; Sousa et al., 1990;
Ayedoun et al., 1998; Benevides et al., 2001). The recently
reported studies of Benevides et al.(2001), who isolated di-
n-propyl disulfide, benzyl hydroxymethyl sulfide and sev-
eral other antifungal polysulfides from the roots of P.
alliacea, as well as the work of Szczepanski et al. (1972)
and Mata-Greenwood et al.(2001) who isolated benzyl 2-
hydroxyethyl disulfide and benzyl 2-hydroxyethyl tri-
sulfide, respectively, encouraged us to search for additional
amino acid precursors that might be present in this plant.
The present paper describes our investigations on
identification of additional S-substituted cysteine deri-
vatives from the root of P. alliacea.Identification and
isolation of their enzymatic breakdown products, thio-
sulfinates, are also reported.
Petiveria alliacea L.(Phytolaccaceae) is an herbaceous
perennial indigenous to the Amazon Rainforest and
widely distributed in other areas including tropical and
Central America, Africa, Sri Lanka, and the south-
eastern United States.Preparations from this plant have
been used extensively in the traditional medicine of South
and Central America for the treatment of many disorders.
They reportedly exhibit antiinflammatory, antimicrobial,
anticancer and stimulant effects, among others.
In a previous contribution (Kubec and Musah, 2001),
identification of two diastereoisomers of S-benzylcys-
teine sulfoxide in P. alliacea, petiveriins A and B was
reported.We also proposed that these amino acids serve
as precursors of the benzyl/phenyl-containing com-
pounds previously detected in this plant (e.g. dibenzyl
sulfides, benzaldehyde, stilbenes, benzyl alcohol, benzoic
2. Results and discussion
An amino acid fraction from the roots was isolated by
cation-exchange chromatography.As revealed by GC
analysis of the extract, P. alliacea appears to be quite a
rich source of several S-substituted cysteine derivatives.
Besides S-benzylcysteine sulfoxides (petiveriins A and
B) which were by far the most abundant components,
*
Corresponding author.Tel :. +1-518-437-3740; fax: +1-518-437-
741.
E-mail address: musah@csc.albany.edu (R.A. Musah).
3
1
Current address: Department of Food Chemistry and Analysis,
Institute of Chemical Technology, Technika 1905, Prague 6, 166 29,
Czech Republic.
´
0031-9422/02/$ - see front matter # 2002 Elsevier Science Ltd.All rights reserved.
PII: S0031-9422(02)00328-X

1
676
R. Kubec et al. / Phytochemistry 61 (2002) 675–680
four additional cysteine derivatives were detected in the
extract.These were S-methyl-, S-ethyl-, S-n-propyl- and S-
(2-hydroxyethyl)cysteine derivatives.Whereas the first
three amino acids were present only in minute amounts
ꢀ
1
(
<3 mg g fr.wt), the content of the fourth one was con-
ꢀ1
siderably higher (ca. 0.2 mg g fr.wt).Therefore, we
focused our attention primarily on isolation and structural
elucidation of the S-(2-hydroxyethyl)cysteine derivative.
Another extract was prepared and analyzed using C18
reversed phase HPLC.As revealed by comparison with
authentic samples, both S-(2-hydroxyethyl)cysteine
sulfoxide (1) and S-(2-hydroxyethyl)cysteine (2) seemed
to be present in the extract.The corresponding fractions
were subsequently isolated by prep.C 18 HPLC and
purified by means of prep.C 8 HPLC, affording 1 and 2
as white solids.
The MALDI-HRMS data of 1 confirmed the antici-
pated molecular formula for S-(2-hydroxyethyl)cysteine
sulfoxide ([MH+] of 182.0483, C H NO S req.
5
11
4
1
Fig.1. Structure of S-(2-hydroxyethyl)cysteine derivatives.
1
82.0482). Although the H NMR signals are complex
and overlapping, the spectrum does fit the structure of
a/1b.The peaks representing the methine protons on
1
MALDI-HRMS of
(C H NO S req.166 0. 532), unambiguously confirming
2
gave [MH+] of 166.0537
1
1
C-2, and the methylene protons on C-3 show H– H
COSY crosspeaks, consistent with the structure, as do
the peaks representing the methylene protons on car-
bons 5 and 6 (see Experimental).Additionally, the 13C
NMR spectrum contained nine signals, indicating that
two diastereomeric forms of the sulfoxide were present.
The presence of two diastereomers of 1 was subse-
quently confirmed by HPLC analysis after derivatiza-
tion with ortho-phthaldehyde (OPA), showing two
nicely separated peaks that had the retention character-
istics identical to the two components of 1 obtained by
synthesis.The amount of 1 isolated from the roots was
too small to allow preparative separation into the cor-
responding diastereomers to determine their absolute
configurations.However, since the absolute configur-
ation of 2 is (R) (see later), it is reasonable to assume
that the same configuration about the ꢀ-carbon occurs
also in both diastereomers of 1.Based on the data
obtained, we can therefore conclude that both (R R )-
5
11
3
the identity of the amino acid as S-(2-hydroxy-
ethyl)cysteine.The absolute configuration of 2 at the
ꢀ-carbon was determined by means of CD spectrometry
and polarimetry, using authentic samples of (R)- and (S)-
S-(2-hydroxyethyl)cysteines for comparison.Both the
CD spectrum (ꢀ" +1.03, 219 nm) and optical rotation
2
0
ꢁ
value (½ꢀŠ +29 ) of 2 were in perfect agreement with
D
those of the (R) isomer.The structure of 2 was therefore
determined to be (R)-S-(2-hydroxyethyl)cysteine (Fig.1).
To the best of our knowledge, the occurrence of 1a,
1b or 2 in nature has not been reported thus far.How-
ever, 2 is a well known metabolite occurring in the urine
and blood of individuals who have been exposed to
ethylene oxide (oxirane), ethylene bromide, vinyl chlo-
ride, and 2-bromo- or 2-chloroethanol (Nachtomi et al.,
1966; Jones and Wells, 1981; Hefner et al., 1975).
Due to their very low content, no effort was made to
isolate the minor S-substituted cysteine derivatives
detected by GC, i.e. S-methyl-, S-ethyl- and S-n-pro-
pylcysteine derivatives.Since the GC method used for
the screening does not permit distinction between
S-substituted cysteines and their sulfoxides, it is not
known whether the derivatives detected in this study were
thioether or sulfoxide forms.Indeed, both may have been
present.Nevertheless, the presence of the sulfoxides
seems to be more likely.Since the total content and relative
proportions of S-substituted cysteine sulfoxides are known
to depend on many factors (e.g. growth conditions and
sulfur and nitrogen supply), higher amounts of S-methyl-,
S-ethyl-, S-propylcysteine derivatives might be present in
plants grown at different locations.
S
C
and (S R )-S-(2-hydroxyethyl)cysteine sulfoxides (1a
S
C
and 1b, respectively, Fig.1) are present in the roots of
P. alliacea.Since these compounds can be viewed as
6
(
-hydroxy analogues of S-ethylcysteine sulfoxide
ethiin), we suggest the trivial names 6-hydroxyethiin A
and 6-hydroxyethiin B for 1a and 1b, respectively.
According to the HPLC/OPA analysis and the 13C
NMR signal intensities observed, the relative ratio of
1
a/1b in the root was approximately 1/1.It is however
possible that different relative proportions of 1a and 1b
may be observed in various parts of the plant as is the
case for petiveriins A and B (Kubec and Musah, 2001).
The IR, H and 13C NMR spectroscopic data of 2
were virtually identical with those of an authentic sam-
ple of S-(2-hydroxyethyl)cysteine.Furthermore, the
1
All attempts to synthesize S-(hydroxymethyl)cysteine,
a possible precursor of the hydroxymethyl-containing

1
R. Kubec et al. / Phytochemistry 61 (2002) 675–680
677
sulfide found by Benevides et al.(2001), were unsuc-
cessful.In accordance with the report of Ratner and
Clarke (1937), the reaction of formaldehyde with
Furthermore, compounds 4–6 represent the first natu-
rally occurring benzyl-containing thiosulfinates to be
reported.
cysteine gave thiazolidine-4-carboxylic acid under all
ꢁ
As revealed by HPLC/OPA analysis of a root homo-
genate after 30 min of standing at room temperature,
both petiveriin A and petiveriin B are enzymatically
cleaved.Since we did not have a fresh sample containing
a fully native enzymatic system, no precise kinetic
study was carried out to determine whether both
petiveriins were depleted at the same rate.Because of
partial overlap of the peaks of OPA-derivatives of 1a
and 1b in HPLC chromatograms by other amino acid
components present in the homogenate, we were also
not able to determine whether both diastereomers of
1 were enzymatically cleaved.A more detailed study
on the enzymatic system of P. alliacea is required to
establish whether there is only one C–S lyase present,
capable of cleaving both 1a/1b and petiveriins A/B,
or whether there are several specific lyases for each
cysteine derivative.
conditions studied (pH 2–10, temp.2–25
C).Also
reactions of formaldehyde with N-acetylcysteine or
N-(tert-butoxycarbonyl)cysteine led to the formation of
N-substituted analogues of thiazolidine-4-carboxylic
acid.Interestingly, even the reaction of bromomethyl
methyl ether (CH OCH Br) with cysteine yielded thia-
3
2
zolidine-4-carboxylic acid as the only ninhydrin-positive
product.Apparently, S-(hydroxymethyl)cysteine is an
extremely unstable compound with a high tendency
towards self-cyclization.Its oxidized form, S-(hydroxy-
methyl)cysteine sulfoxide, is likely to be more stable.
However, if present in the extract, at least a part of the
sulfoxide would have also been converted into the
cyclized form during the reduction step of the GC deri-
vatization procedure.No sign of thiazolidine-4-car-
boxylic acid was found, implying that there was neither
S-(hydroxymethyl)cysteine nor its sulfoxide present at
Generally, thiosulfinates are quite thermolabile and
usually decompose when analyzed by common GC
procedures (employing high injection/oven tempera-
tures and long, narrow capillary columns) (Block,
1992).As we found out, thiosulfinates 3–6 do not sur-
vive GC analysis.Even when very mild injection/oven
temperatures were used (injection temp.as low as
ꢀ
1
levels >1 mg g fr.wt in the sample we analyzed.In
addition, none of the following compounds were detec-
ꢀ
1
ted by GC at the level of 1 mg g fr.wt: S-isopropyl-,
S-allyl-, S-(1-propenyl)-, S-n-butyl-, S-isobutyl, S-sec-
butyl-, S-n-pentylcysteine derivatives.The next higher
homologue of 2, S-(3-hydroxypropyl)cysteine, was also
not found.However, the presence of some additional
analogues cannot be ruled out.
ꢁ
100 C), these labile compounds decomposed during the
run.They gave rise to the parent disulfides and, in the
case of 4 and 6, also to a compound that was tentatively
identified as thiobenzaldehyde [EIMS, 70 eV, m/z 124
There are two major S-substituted cysteine sulfoxides
present in the intact tissue of P. alliacea, namely S-ben-
zyl- and S-(2-hydroxyethyl)cysteine sulfoxides.In the-
ory, these amino acids should give rise to four
thiosulfinates (two symmetrical and two unsymmetrical
ones) upon the action of a C–S lyase (Fig.2).All four of
these thiosulfinates were synthesized to facilitate their
HPLC detection and subsequent isolation.An HPLC
+
+
(2, M +2), 122 (52, M ), 121 (100), 93 (3), 84 (6), 78
(15), 77 (26)].Based on the above observations, we
conclude that GC analyses cannot provide a true repre-
sentation of the compounds present in a fresh homo-
genate of P. alliacea.
As we proposed in the previous study (Kubec and
Musah, 2001), the benzyl/phenyl-containing compounds
identified in this plant (e.g. dibenzyl sulfides, benzalde-
hyde, trithiolaniacin, stilbenes, benzyl mercaptan, ben-
zoic acid) are not present in the intact tissue of
P. alliacea.In fact, these compounds are only degrada-
tion products of the thiosulfinates 4–6 that arise by the
action of a C–S lyase on S-substituted cysteine sulf-
oxides upon cellular disruption.Indeed, we did not find
significant amounts of dibenzyl sulfides, benzaldehyde or
method employing a C column was developed.This
8
methodology allowed an excellent separation, even of
the regioisomers 4 and 5.Indeed, all four of these thio-
sulfinates were detected in a diethyl ether extract of a
root homogenate.The thiosulfinates 4–6 were subse-
quently isolated by preparative C8 HPLC and fully
characterized by spectroscopic methods (NMR, IR,
MALDI/MS, and UV).The content of 3 in the extract was
too low to allow its isolation.It was, however, detected and
unambiguously identified by comparing its retention time
and UV spectrum with that of an authentic sample pre-
pared by synthesis.As expected, S-benzyl phenylmethane-
thiosulfinate (6) was the most abundant thiosulfinate found
in the extract, followed by 4 and 5.Analogous to the alliin/
allicin and marasmin/marasmicin systems in garlic (Allium
sativum L.) and society garlic (Tulbaghia violacea Harv.),
respectively, we suggest using the trivial name petivericin
for 6.To the best of our knowledge, none of the thio-
sulfinates 3–6 has been observed in nature thus far.
stilbenes in a Et O extract of a fresh root homogenate by
2
means of C8 HPLC.The predominant thiosulfinate of
P. alliacea, S-benzyl phenylmethanethiosulfinate (6,
petivericin), seems to be the precursor of the majority of
the benzyl/phenyl-containing compounds.It was shown
that 6 can decompose into dibenzyl disulfide and tri-
sulfide, benzaldehyde, stilbenes and benzyl mercaptan,
among others (Furukawa et al., 1973). Analogous to
other thiosulfinates, petivericin can also dispropor-
tionate into the corresponding disulfide and thiosulfo-

1
678
R. Kubec et al. / Phytochemistry 61 (2002) 675–680
Fig.2.Enzymatic formation of thiosulfinates in P. alliacea [3—S-(2-hydroxyethyl) 2-(hydroxyethane)thiosulfinate; 4—S-(2-hydroxyethyl) phe-
nylmethanethiosulfinate; 5—S-benzyl 2-(hydroxyethane)thiosulfinate; 6—S-benzyl phenylmethanethiosulfinate (petivericin)].
nate.The latter compound can undergo further decom-
position, yielding mainly sulfur dioxide, stilbenes, ben-
zyl mercaptan, and dibenzyl sulfide and disulfide
3. Experimental
3.1. General experimental procedures and plant material
(
1
Smythe, 1922; Kice et al., 1960; Chatgilialoglu et al.,
980; White and Dellinger, 1985).It remains to be seen
All apparatus used in the present study were identical
with those described previously (Kubec and Musah,
2001).The roots of P. alliacea originated from the same
batch that was analyzed in the previous study.They had
whether other likely decomposition products, such as
S-benzyl phenylmethanethiosulfonate, phenylmethane-
sulfinic and phenylmethanesulfonic acids are present in
P. alliacea extracts.Benzoic acid and benzyl alcohol
might be formed by the Canizzaro reaction from
abundantly occurring benzaldehyde and subsequently
give rise to benzyl benzoate.The thiosulfinates 4 and 5
are possible precursors of benzyl 2-hydroxyethyl dis-
ulfide and trisulfide previously identified by Mata-
Greenwood et al.(2001) and Szczepanski et al.(1972),
respectively.However, the precursor and formation
pathway of benzyl hydroxymethyl sulfide recently
detected by Benevides et al.(2001) still remain to be
determined.
Most of the above mentioned compounds (thiosulfi-
nates 3–6, the corresponding thiosulfonates and mono-,
di- and trisulfides) are currently being tested in our
laboratory for their antibacterial and antifungal activ-
ities, as well as for their antiinflammatory and anti-
cancer properties.We believe that these compounds are
responsible for many of the reported physiological
effects of P. alliacea.
ꢁ
been stored in a freezer at ꢀ30 C for several months
before the experiments.
3.2. Extraction and purification
An amino acid fraction was obtained from the roots
(315 g) as described previously (Kubec and Musah,
2001).It was subjected to prep.C
HPLC and the
8
1
fractions eluting at 3.5 and 4.2 min were collected, eva-
porated and purified by reinjection onto a prep.C 8
HPLC column to yield 1a/1b (6 mg) and 2 (11 mg),
respectively.The HPLC conditions employed were as fol-
lows: 10 mM KH PO buffer (A, pH 7.0) and MeCN (B)
2
4
as the mobile phase (14 ml min 1), A/B 99/1 from t=0–7
min, then to 20/80 from t=7–15 min, with this being held
for 25 min.HPLC/OPA analyses were performed accord-
ing to the method of Ziegler and Sticher (1989).
ꢀ
Thiosulfinates 3–6 were isolated from a root homo-
genate that was prepared as follows.The roots (190 g)

1
R. Kubec et al. / Phytochemistry 61 (2002) 675–680
679
were mixed with H O (300 ml) and homogenized using a
2
3.5. (R R )/(S R )-R-(2-Hydroxyethyl)cysteine sulf-
S C S C
blender.The resulting slurry was allowed to stand at
room temp.for 30 min, filtered and the filtrate
oxide (1a/1b)
ꢁ
extracted with Et O (2Â300 ml).Additional Et 2O
White solid; mp 137–138 C; UV l
(H O) nm (log
max 2
2
"): 192 (3.56), 218 (sh) (3.01); IR (KBr) ꢁmax cm 1:
ꢀ
(300 ml) was used for washing the filter cake.The
Et O fractions were combined, evaporated to dryness
3670–2900 (s, br), 1633 (vs), 1503 (m), 1384 (m), 1352
1
2
and the yellow, strongly smelling residue was redis-
solved in MeCN (20 ml).The extract was subjected
(m), 1062 (m), 1021 (m), 990 (m); H NMR (400 MHz;
D O): ꢂ 3.08–3.45 (4H, m, H-3, H-5), 3.87–3.98 (2H, m,
2
1
3
to prep.C
H O (A), MeCN (B) as the mobile phase (18 ml
HPLC using the following conditions:
H-6), 4.124.18 (1H, m, H-2); C NMR (75 MHz; D O):
2
8
0
0
ꢂ 50.3 (C-2), 51.0 (C-3), 51.1 (C -2), 51.5 (C -3), 54.4
0
2
min 1), from A/B 98/2 at t=0 its 0/100 in 25 min,
ꢀ
(C-5), 54.6 (C-6; C -6), 55.1 (C -5), 171.4 (C-1), 171.5
0
0
(C -1); MALDI-HRMS [MH ] 182.0483 (C H NO S
5 11 4
+
this being held for 15 min.The fractions eluting at 13 9. ,
1
4.4 and 22.0 min were collected, 4 (12 mg), 5 (4 mg) and
(98 mg), respectively.
req.18 02 4. 82); TLC
4:1:1), R 0.47 (n-PrOHH O, 7:3).
Rf 0.20 (n-BuOHH OHOAc,
2
6
f
2
3
.3. GC analyses
3.6. (R)-S-(2-Hydroxyethyl)cysteine (2)
ꢁ
22
D
ꢁ
An amino acid extract was prepared from the roots as
White solid; mp 183–184 C; ½ꢀŠ : +29 (H O; c 0.1);
max 2 max
2
ꢁ
described above and it was analyzed by GC after deriva-
tization with ethyl chloroformate (ECF) and reduction
with sodium iodide (Kubec et al., 1999). S-(4-Chlor-
obenzyl)cysteine, added to the samples before extraction,
was used as an internal standard.
CD ꢀ"
(H O; c 0.1; 22 C): +1.0 (219 nm); UV l
(H O) nm (log "): 190 (3.37), 204 (sh) (3.22); IR (KBr)
ꢁmax cm : 3331 (m, br), 3060–2900 (s, br), 1602 (vs),
1431 (s), 1410 (s), 1353 (s), 1317 (s), 1062 (m), 1000 (m),
2
ꢀ
1
1
850 (m); H NMR (300 MHz; D O): ꢂ 2.79 (2H, t,
2
Thiosulfinates were analyzed using a Rtx-1 fused
silica capillary column (30 mÂ0.25 mm; 25 mm; Restek
Corp.), employing the following temperature program:
J=6.2 Hz, H-5), 3.07 (1H, dd, J=7.4, 14.7 Hz, H-3a),
3.17 (1H, dd, J=4.3, 14.7 Hz, H-3b), 3.78 (2H, t, J=6.1
Hz, H-6), 3.95 (1H, dd, J=4.3, 7.4 Hz, H-2); 13C NMR
ꢁ
ꢁ
ꢁ
1
00 C (held for 2 min), raised linearly to 260 C at 6 C
ꢀ1
(75 MHz; D O): ꢂ 32.3 (C-3), 33.9 (C-5), 53.9 (C-2), 60.2
2
min 1.Helium (0 7. ml min
gas.Different injection temperatures were studied (100–
ꢀ
) was used as the carrier
(C-6), 173.0 (C-1); MALDI-HRMS [MH] 166.0537
(C H NO S req.16 60 .532); TLC R 0.38 (n-BuOH-
+
5
11
3
f
ꢁ
2
60 C).
H OHOAc, 4:1:1), R 0.61 (n-PrOHH O, 7:3).
2 f 2
3
.4. Reference compounds
3.7. (S)-S-(2-Hydroxyethyl)cysteine (2b)
2
D
2
ꢁ
S-(2-Hydroxyethyl)cysteine and S-(3-hydroxypropyl)
White solid; ½ꢀŠ : ꢀ27 (H O; c 0.1); CD ꢀ"
(H O;
max 2
2
ꢁ
cysteine were synthesized by the reaction of l-cysteine
with 2-bromoethanol or 1-chloro-3-propanol, respec-
tively (Shiraiwa et al., 1998). All of the other S-sub-
stituted cysteine derivatives were obtained analogously.
A mixture of S-(2-hydroxyethyl)-l-cysteine sulfoxide
diastereomers (1a, 1b) was synthesized by oxidation
with H O as described by Stoll and Seebeck (1949).
c 0.1; 22 C): ꢀ0.94 (219 nm); all other analytical data
identical with those of 2.
3.8. S-(2-Hydroxyethyl) 2-(hydroxyethane)thiosulf-
inate (3)
Yellowish oil; UV lmax (EtOH) nm (log "): 204 (3.70),
252 (3.37); IR (neat) ꢁmax cm : 3380 (s, br), 2933 (m),
2879 (m), 1399 (m), 1285 (m), 1052 (vs), 1002 (s); H
NMR (300 MHz; CD OD): ꢂ 3.25–3.38 (4H, m, H-2,
2
2
ꢀ
1
Thiazolidine-4-carboxylic acid was prepared by con-
densation of formaldehyde with l-cysteine (Ratner and
Clarke, 1937).2-Hydroxyethyl benzyl disulfide and
bis(2-hydroxyethyl) disulfide were prepared according
to the method of Ayodele et al.(2000).Dibenzyl dis-
ulfide was purchased from Aldrich. S-(2-Hydroxyethyl)
phenylmethane- (4), S-benzyl (2-hydroxyethane)- (5)
and S-benzyl phenylmethanethiosulfinates (6) were syn-
thesized by oxidation of the parent disulfides with an
1
3
H-5), 3.84 (2H, m, H-1), 3.98 (2H, t, J=5.7 Hz, H-6);
3
1
C NMR (75 MHz; CD OD): ꢂ 36.8 (C-5), 56.5 (C-2),
3
+
60.0 (C-1), 62.7 (C-6); MALDI-HRMS [MH]
171.0142 (C H O S req.171 0. 144).
4
10
3 2
3.9. S-(2-Hydroxyethyl) phenylmethanethiosulfinate
(4)
equimolar amount of 3-chloroperoxybenzoic acid (in
ꢁ
CHCl , at ꢀ20 C for 30 min). S-(2-Hydroxyethyl)
3
ꢁ
(2-hydroxyethane)thiosulfinate (3) was obtained by oxi-
dation of bis(2-hydroxyethyl) disulfide with 30% H O .
White solid; mp 48–50 C; UV l
"): 206 (4.26), 224 (4.09), 266 (3.23); IR (KBr) ꢁ
(EtOH) nm (log
max
2
2
max
ꢀ
1
All of the thiosulfinates were purified using prep.C 8
HPLC.
cm : 3413 (m, br), 1452 (m), 1406 (m), 1400 (m), 1072
1
(vs), 1053 (vs), 1011 (m), 762 (m), 696 (s); H NMR (300

1
680
R. Kubec et al. / Phytochemistry 61 (2002) 675–680
MHz; CD OD): ꢂ 3.23 (2H, m, SCH ), 3.76 (2H, m,
3
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nosulfur compounds as potential fungicides: the preparation and
properties of some substituted benzyl 2-hydroxyethyl oligosulfides.
Phosphorus, Sulfur Silicon Relat.Elem 159, 123–142.
2
CH OH), 4.39 (1H, d, J=12.9 Hz, CH S(O)-a), 4.49
2
2
(
1H, d, J=12.9 Hz, CH S(O)-b), 7.327.45 (5H, m,
2
Harom); 13C NMR (75 MHz; CD OD): ꢂ 36.1 (SCH ),
3
2
62.7 (CH OH), 63.1 (CH S(O)), 129.7, 129.8, 131.6,
2 2
1
31.7 (Carom); MALDI–HRMS [MH]+ 217.0352
Benevides, P.J.C., Young, M.C.M., Giesbrecht, A.M., Roque, N.F.,
Bolzani, V.S., 2001. Antifungal polysulphides from Petiveria allia-
cea L.Phytochemistry 57, 743–747.
(
C H O S req.217 0. 351).
9 12 2 2
Block, E., 1992. The organosulfur chemistry of the genus Allium—
implications for the organic chemistry of sulfur.Angew.Chem ., Int.
Ed.Engl.31, 1135–1178.
3
.10. S-Benzyl (2-hydroxyethane)thiosulfinate (5)
ꢁ
White solid; mp 50–51 C; UV l (EtOH) nm (log
): 206 (4.25), 224 (3.99), 260 (3.37); IR (KBr) ꢁ
Chatgilialoglu, C., Gilbert, B.C., Gill, B., Sexton, M.D., 1980. Elec-
tron spin resonance studies of radicals formed during the thermo-
lysis and photolysis of sulphoxides and thiolsulphonates.J.Chem.
Soc.Perkin 2 1141–1150.
max
"
cm : 3387 (m, br), 1493 (w), 1453 (m), 1069 (vs), 1055
max
ꢀ1
1
(vs), 995 (m), 701 (s); H NMR (300 MHz; CD OD): ꢂ
3
Furukawa, M., Tsuiji, S., Kojima, Y., Hayashi, S., 1973. The reaction
of benzyl phenylmethanethiosulfinate with amines.Chem.Pharm.
Bull 21, 2391–2395.
3
CH OH), 4.39 (2H, s, CH S), 7.24–7.43 (5H, m, Harom);
.22–3.37 (2H, m, S(O)CH ), 3.93–3.97 (2H, m,
2
2
2
1
3
Hefner Jr., R.E., Watanabe, P.G., Gehring, P.J., 1975. Fate of inhaled
vinyl chloride monomer in rats.Environ.Health Perspect.11, 85–95.
Jones, A.R., Wells, G., 1981. The comparative metabolism of 2-bro-
moethanol and ethylene oxide in the rat.Xenobiotica 11, 763–770.
Kice, J.L., Parham, F.M., Simons, R.M., 1960. The thermal decom-
position of thiolsulfonates.J.Am.Chem.Soc.82, 834–842.
C NMR (75 MHz; CD OD): ꢂ 37.7 (CH S), 56.5
3
2
(
(
S(O)CH ), 59.6 (CH OH), 128.8, 129.8, 130.2, 138.3
2 2
Carom); MALDI-HRMS [MH]+ 217.0352 (C H O S
req.217 0. 351).
9 12 2 2
Kubec, R., Svobodova
determination of S-alk(en)ylcysteine sulfoxides.J.Chromatogr.A
62, 85–94.
, M., Velısek, J., 1999. Gas chromatographic
´ ˇ
´
3
.11. S-Benzyl phenylmethanethiosulfinate (6)
8
ꢁ
White solid; mp 77–78 C; UV l (EtOH) nm (log
): 208 (4.43), 226 (4.30), 266 (3.36); IR (KBr) ꢁ
max
Kubec, R., Musah, R.A., 2001. Cysteine sulfoxide derivatives in Peti-
veria alliacea.Phytochemistry 58, 981–985.
"
cm : 3445 (w, br), 2968–2900 (w), 1493 (w), 1451 (m),
max
ꢀ1
Mata-Greenwood, E., Ito, A., Westenburg, H., Cui, B., Mehta, R.G.,
Kinghorn, A.D., Pezzuto, J.M., 2001. Discovery of novel inducers
of cellular differentiation using HL-60 promyelocytic cells.Anti-
cancer Res.21, 1763–1770.
1
1
077 (s), 1055 (s), 761 (m), 695 (s); H NMR (300 MHz;
acetone): d 4.29 (2H, s, SCH ), 4.35 (1H, d, J=12.9 Hz,
2
CH S(O)-a), 4.43 (1H, d, J=12.9 Hz, CH S(O)-b),
7
2
2
Nachtomi, E., Alumot, E., Bondi, A., 1966. The metabolism of ethyl-
ene dibromide in the rat I.Identification of detoxification products
in urine.Israel J.Chem.4, 239–246.
.24–7.42 (5H, m, Harom); 13C NMR (75 MHz; acetone):
ꢂ 35.7 (SCH ), 62.6 (CH S(O)), 128.2, 129.0, 129.2,
2
2
Ratner, S., Clarke, H.T., 1937. The action of formaldehyde upon
cysteine.J.Am.Chem.Soc.59, 200–206.
1
[
29.4, 129.9, 131.2, 131.8 (Carom); MALDI-HRMS
MH]+ 263.0564 (C H OS req.263 0. 559).
1
4
14
2
Shiraiwa, T., Tadokoro, K., Tanaka, H., Nanba, K., Yokono, N.,
Shibazaki, K., Kubo, M., Kurokawa, H., 1998. Synthesis of opti-
cally active 1,4-thiazane-3-carboxylic acid via optical resolution by
Acknowledgements
preferential
crystallization
of
(RS)-2-amino-3-[(2-chlor-
oethyl)sulfanyl]propanoic acid hydrochloride.Biosci.Biotechnol.
Biochem.62, 2382–2387.
The authors would like to thank Dr.Eric Block for
helpful suggestions and critical reading of the manu-
script.We also thank Dr.Gary Siuzdak at the Scripps
Research Institute Center for Mass Spectrometry (La
Jolla, CA) for technical support.Support for this work
was provided by the Research Foundation of the State
University of New York at Albany.
Smythe, J.A., 1922. Decomposition of benzyl disulphoxide. J. Chem.
Soc.121, 1400–1405.
Sousa, J.R., Demuner, A.J., Pinheiro, J.A., Breitmaier, E., Cassels,
B.K., 1990. Dibenzyl trisulphide and trans-N-methyl-4-methoxy-
proline from Petiveria alliacea.Phytochemistry 29, 3653–3655.
¨
Stoll, A., Seebeck, E., 1949. Uber die Spezifitat der Alliinase und die
¨
Synthese mehrerer dem Alliin verwandter Verbindungen.Helv.
Chim.Acta 32, 866–876.
Szczepanski, C., Zgorzelak, P., Hoyer, G.-A., 1972. Isolierung, Struk-
¨
turaufklarung und Synthese einer antimikrobiell wirksamen Sub-
stanz aus Petiveria alliacea L.Arzneim -. Forsch.22, 1975–1976.
White, R.C., Dellinger, D., 1985. Photolysis of benzyl toluene-a-thio-
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