A novel monoacylglycerol lipase inhibitor with analgesic and anti-inflammatory activity

Article abstract of DOI:10.1016/j.bmcl.2008.09.039

A variety of long chain 1,2-diamines and related compounds were synthesized and tested for their activity on fatty acid amide hydrolase (FAAH) and monoacyglycerol lipase (MGL). (2S,9Z)-Octadec-9-ene-1,2-diamine selectively inhibits MGL (K_i 21.8μ M) without significantly affecting FAAH. This compound exhibited interesting in vivo analgesic and anti-inflammatory properties, suggesting that selective inhibitors of MGL may be valuable novel agents for the treatment of inflammatory pain.

Full text of DOI:10.1016/j.bmcl.2008.09.039

Bioorganic & Medicinal Chemistry Letters 18 (2008) 5424–5427
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
A novel monoacylglycerol lipase inhibitor with analgesic
and anti-inflammatory activity
Victoria Magrioti a,b, George Naxakis a, Dimitra Hadjipavlou-Litina c,
Alexandros Makriyannis b, George Kokotos a,
*
a Laboratory of Organic Chemistry, Department of Chemistry, University of Athens, Panepistimiopolis, Athens 15771, Greece
b Center for Drug Discovery, Northeastern University, 116 Mugar Hall, Boston, MA 02115, USA
c Department of Pharmaceutical Chemistry, University of Thessaloniki, 540 06 Thessaloniki, Greece
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 29 July 2008
Revised 8 September 2008
Accepted 9 September 2008
Available online 12 September 2008
A variety of long chain 1,2-diamines and related compounds were synthesized and tested for their activ-
ity on fatty acid amide hydrolase (FAAH) and monoacyglycerol lipase (MGL). (2S,9Z)-Octadec-9-ene-1,2-
diamine selectively inhibits MGL (Ki 21.8 lM) without significantly affecting FAAH. This compound
exhibited interesting in vivo analgesic and anti-inflammatory properties, suggesting that selective
inhibitors of MGL may be valuable novel agents for the treatment of inflammatory pain.
Ó 2008 Elsevier Ltd. All rights reserved.
Keywords:
1,2-Diamines
Endocannabinoids
Fatty acid amide hydrolase
FAAH
Inhibitor
Monoacyglycerol lipase
MGL
The discovery of the CB1 and CB2 cannabinoid receptors as well
as the endogenous ligand involved in their activation opened a new
era in cannabinoid research.1,2 The key endogenous ligands desig-
nated as endocannabinoids are anandamide (1) and 2-arachido-
noylglycerol (2-AG, 2) (Fig. 1). Of these, 2-AG has been shown to
be the most abundant and more potent endocannabinoid.3 2-AG
exhibits full agonist efficacy at both CB1 and CB24 and its physio-
logical levels in rat brain exceed those of anandamide by several
orders of magnitude.3b Although the endocannabinoid system
has received much attention in recent years as a target for the dis-
covery of novel therapeutic agents,5 the role and function of 2-AG
are less understood.
Anandamide and 2-AG are produced by neurons when the need
arises, act near their site of biosynthesis, and are rapidly metabo-
lized so that their biological activity is terminated. Both ananda-
mide and 2-AG are hydrolyzed by fatty acid amide hydrolase
(FAAH).6 However, existing evidence indicates that the most likely
candidate for 2-AG hydrolytic deactivation is monoacylglycerol li-
pase (MGL), a serine hydrolase that converts 1- and 2-monoacyl-
glycerols into fatty acid and glycerol.7 Dinh et al. cloned MGL
from a rat brain cDNA,8 and demonstrated that RNA interference
suggested a primary role for MGL in the degradation of 2-AG.9
More recently, Makriyannis and collaborators have characterized
the binding domain of this enzyme using a proteomic approach.10
Although a plethora of FAAH inhibitors have been developed,1,2,11
only few MGL inhibiting ligands are available.
Various nonspecific serine hydrolase inhibitors such as methyl-
arachidonoyl fluorophosphonate (3, MAFP) (Fig. 2), hexadec-
ylsulfonyl fluoride (AM374) and phenylmethylsulfonyl fluoride
(PMSF) inhibit purified MGL, or 2-AG-degrading enzymatic activity
in rat cerebellar membranes.6d,8,12 In addition, sulfhydryl-specific
compounds, like N-arachidonylmaleimide (4, NAM) have been
shown to inhibit MGL.13 Arachidonoyl trifluoromethyl ketone (5,
ATFMK)12 as well as arachidonoyl glycerol derivatives such as com-
pound 6 also interact with MGL.14 It has been reported that MGL
activity can be specifically and noncompetitively inhibited by
two compounds, URB602 (7) and URB754 (8) (Fig. 2).15 However,
O
O
OH
OH
OH
N
H
O
2-Arachidonoylglycerol (2-AG)
Anandamide
1
2
* Corresponding author. Tel.: +30 210 7274462; fax: +30 210 7274761.
E-mail address: gkokotos@chem.uoa.gr (G. Kokotos).
Figure 1. The most important endocannabinoids.
0960-894X/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmcl.2008.09.039

V. Magrioti et al. / Bioorg. Med. Chem. Lett. 18 (2008) 5424–5427
5425
Table 1
O
Inhibitory results on FAAH and MGLa
O
P
F
OMe
N
O
Structure
FAAH inhibition MGL inhibition Ki for MGL
(%)
(%)
(lM)
4, NAM
3, MAFP
O
H
N
OH
OH
O
O
( )13
O
OH
23.8
27.5
CF3
O
12
CF3
( )13
OH
33.6
31.3
31.2
4.9
31.5
30.0
30.3
49.9
42.2
0.0
5, ATFMK
6
NH2.HCl
13
H
N
( )13
N
O
H
N
OH
NH2.HCl
14
O
O
O
7, URB602
( )13
8, URB754
.
NH2 HCl
58.7
21.8
39.0
.
NH2 HCl
Figure 2. Inhibitors of monoacylglycerol lipase.
15
( )6
( )7
.
NH2 HCl
a recent report showed that both URB602 and URB754 had no ef-
fect on the hydrolysis or signaling capacity of 2-AG in rat brain.16
Most recently, it has been reported that locally injected 2-AG de-
creased pain behavior in a dose-dependent manner in an inflam-
matory model of pain.17 It is thought that the antinociceptive
effect of 2-AG is mediated through the CB2 receptor.
The novel finding that the exogeneous application of 2-AG in-
duces peripheral antinociception,17 reveals the therapeutic poten-
tial of MGL inhibitors for the treatment of inflammatory pain.18
Since both FAAH and MGL may hydrolyse 2-AG, it is of great impor-
tance to develop selective inhibitors of these enzymes in order to
fully explore the physiological role for 2-AG. Here, we describe
our efforts towards the synthesis of MGL selective inhibitors and
the in vivo anti-inflammatory and analgesic properties of such a
compound.
During the last years we have developed a variety of inhibitors
of lipolytic enzymes (pancreatic and gastric lipases as well as phos-
pholipases cPLA2 and iPLA2Þ,19–25 and we have shown that the
cytosolic phospholipase A2 inhibitor AX048 produces a potent anti-
hyperalgesic action.26 All of these lipolytic enzymes are serine
hydrolases with a mechanism of action involving a serine residue
at the catalytic site interacting with a 2-oxoamide functionality
of the inhibitors. Since MGL is also a serine hydrolase, we have
incorporated the 2-oxoamide functionality in our MGL inhibitor
design. Towards this end, we synthesized a lipid analog carrying
the 2-oxoamide of ethanolamine. 2-Oxoamide 12 was prepared
from the tert-butyl ether of ethanolamine as described in Scheme
1. This compound exhibited weak inhibitory activity towards both
FAAH and MGL, with no selectivity (Table 1).
.
NH2 HCl
21
( )6
( )7
.
NH2 HCl
25.9
0.0
.
NH2 HCl
22
( )4
NH2.HCl
NH2.HCl
25a
( )4
O
.
NH2 HCl
NH2.HCl
( )5
30.9
24.0
25.9
0. 0
25b
O
( )6
( )7
NH2
NH2.HCl
29
Percent inhibition of 2-AG hydrolysis using 100
a
lM concentrations.
mine 21 is presented in Scheme 2. L-Glutamic acid was used as
starting material and aminoaldehyde 16 was prepared according
to literature procedure.29 After a Horner–Wadsworth–Emmons
reaction, hydrogenation with simultaneous reduction of the azide
group and Boc protection, the key intermediate ester 18 was ob-
tained. Compound 18 was then reduced to aldehyde 19, which
was allowed to react with the appropriate ylide to yield diamine
O
O
a
b
EtO
N3
N(Boc)2
H
N3
At the same time, we synthesized a series of long chain 1,2-dia-
mines and 1,2-amino alcohols containing a saturated chain or a
chain corresponding to that of oleic acid chain. (S)- and (R)-2-
aminohexadecanol27 (13, 14) and 1,2-diaminohexadecane28 (15)
were prepared as previously described. The synthesis of 1,2-dia-
N(Boc)2
16
17
O
O
c
H
NHBoc
N(Boc)2
EtO
NHBoc
N(Boc)2
19
18
e
OH
H
( )13
d
( )7
( )5
NH2.HCl
NH2.HCl
21
( )7
( )5
20
NHBoc
N(Boc)2
a
b
H2N
N
O
O
O
9
10
O
O
H
N
c
H
O
H
N
( )13
OH
( )13
O
( )7
( )5
NH2.HCl
NH2.HCl
22
O
N3
O
N(Boc)2
12
11
Scheme 1. Synthesis of 2-oxoamide 12. Reagents: (a) CH3(CH2Þ13CHOHCOOH,
N-(3-dimethylaminopropyl)-N0-ethylcarbodiimide hydrochloride, HOBt, Et3N,
CH2Cl2; (b) AcNH-TEMPO, NaOCl, NaBr, EtOAc=PhCH3=H2O; (c) 50% TFA=CH2Cl2.
Scheme 2. Synthesis of 1,2-diamines 21 and 22. Reagents: (a)
EtOOCCH@CHCH2Pð@OÞðOEtÞ2, LiOH, THF; (b) H2, 10% Pd/C, Boc2O, MeOH; (c)
DIBALH, Et2O; (d) C9H19PþPh3Brꢀ, KHMDS, toluene; (e) 4 N HCl=Et2O.

5426
V. Magrioti et al. / Bioorg. Med. Chem. Lett. 18 (2008) 5424–5427
O
30
R1
a
H
N3
N(Boc)2
N3
N(Boc)2
25
16
23a, b
R1
20
15
10
5
R1
NH2.HCl
NH2.HCl
25a, b
NHBoc
N(Boc)2
c
b
24a, b
23-25
R1
a
b
C6H5
p
-CH3(CH2)5OC6H4
0
Scheme 3. Synthesis of diamines 25a and 25b. Reagents: (a) R1PþPh3Brꢀ, KHMDS,
toluene; (b) H2, 10% Pd/C, Boc2O, MeOH; (c) 4 N HCl=Et2O.
5
10
15
20
25
30
min after CH3COOH administration
Figure 3. In vivo analgesic activity of inhibitors 21 and 22. Control (j), 22 (3.6 mg/
20. Deprotection gave diamine 2130 which encompasses an oleic
acid chain. Its enantiomer 22 was prepared correspondingly from
kg, r), 21 (3.6 mg/kg, N), 22 (36 mg/kg, ), 21 (36 mg/kg, ꢂ), aspirin (200 mg/kg,
+
ꢁ
).
D
-glutamic acid.
higher MGL inhibitory activity than compound 21.10 Conversely,
the carboxamide of 2-amino oleic (29) acid does not inhibit MGL,
but weakly inhibits FAAH. Thus, it appears that replacement of
the CH2NH2 moiety of compound 21 by the CONH2 led to a com-
pound without inhibition towards MGL.
Subsequently, compound 21 was tested for its analgesic and
anti-inflammatory activity using models previously described.24
The acetic acid writhing test was used to assess analgesic activity
in rats. Acetylsalicylate was used as a reference drug and was
administered ip. As shown in Figure 3, 21 exhibited analgesic activ-
ity at a dose of 3.6 mg/kg (ip). A more potent effect was observed at
a 10-fold higher dose indicating a dose-dependent effect. Further-
more, its enantiomer 22 exhibited similar analgesic activity at the
high dose of 36 mg/kg, but had weaker analgesic potency at the
lower dose of 3.6 mg/kg.
The rat paw carrageenan-induced edema assay was employed
as a model for acute inflammation. Compound 21 exhibited
in vivo anti-inflammatory activity (ED50 0.01 mmol/kg) compara-
ble to that of the reference drug indomethacin (47% inhibition of
inflammation at 0.01 mmol/kg administered ip).
In conclusion, we synthesized a variety of long chain 1,2-dia-
mines and related compounds and studied their effects on the
endocannabinoid deactivating enzymes FAAH and MGL. We dem-
onstrated that (2S,9Z)-octadec-9-ene-1,2-diamine is a novel selec-
Diamines 25a and 25b were prepared from aminoaldehyde 16
through a Wittig reaction followed by hydrogenation and simulta-
neous transformation of the azide group into a Boc-protected
amine, and deprotection (Scheme 3).
Previously, we used Boc-protected (S)-2-amino oleic31 acid to
prepare a potent inhibitor of human pancreatic lipase, which
resembled the natural substrate of the enzyme.32 We now used
this optically pure unnatural 2-amino acid (26) to prepare the car-
boxamide of 2-amino oleic acid (29) (Scheme 4).
All new compounds were tested for their abilities to inhibit 2-
AG hydrolysis by FAAH and MGL (Table 1). Partially purified FAAH
and MGL enzyme preparations were obtained from adult Sprague–
Dawley rat brains purchased from Pel-Freeze Biologicals according
to previously reported procedures,33,34 while the FAAH and MGL
inhibition assays were performed as previously described.34–36
2-Oxoamide 12 presented low inhibition and no selectivity to-
wards the two enzymes. (S)- or (R)-2-aminohexadecanol (13, 14)
as well as 1,2-diaminohexadecane (15) inhibit both enzymes
equally. However, the unsaturated diamine, (2S,9Z)-octadec-9-
ene-1,2-diamine dihydrochloride (21), inhibited MGL selectively
with a Ki value of 21.8 lM. This compound did not inhibit FAAH
significantly. Compound 21 also exhibited modest stereoselectivi-
ty. Its enantiomer (2R,9Z)-octadec-9-ene-1,2-diamine dihydrochlo-
ride (22), inhibits MGL with a Ki value of 39
inhibitory activity (25% at a 100 M).
Diamine 25a was totally inactive towards both enzymes, while
25b, which carries a para alkoxy chain, was weakly active. Thus, it
appears that diamines require the presence of a long lipophilic
chain in order to successfully inhibit MGL. Our results also indicate
that the presence of a long monounsaturated chain corresponding
to oleic acid in compound 21 is a key requirement for the selective
inhibition of MGL. Recently, an oleoyl-chain phosphonate, UP-101,
was reported to be a potent inhibitor of MGL.37 Furthermore,
according to a recent article, NAM exhibits approximately a 30-fold
lM, and some FAAH
tive inhibitor of MGL activity (Ki 21.8 lM) with in vivo analgesic
l
and anti-inflammatory properties. Thus, synthetic selective inhibi-
tors of MGL are potential candidates for the development of novel
analgesic agents.
Acknowledgments
The project was co-funded by the European Social Fund and
National Resources-(EPEAEK II) PYTHAGORAS; Fund for Interna-
tional Collaborations, Northeastern University; and from the Na-
tional Institutes on Drug Abuse (DA3801). The authors are
grateful to Ying Pei and Nikolai M. Zvonok for the biochemical
assays.
O
O
NH2
O
a
c
b
References and notes
( )7
( )5
27
( )7
( )5
26
OH
OH
NHBoc
1. Kokotos, G. Endocannabinoids. In Bioactive Lipids; Kokotos, G., Nicolaou, A.,
Eds.; The Oily Press: Bridgewater, England, 2004; p 245.
2. Lambert, D. M.; Fowler, C. J. J. Med. Chem. 2005, 48, 5059.
O
3. (a) Mechoulam, R.; Ben-Shabat, S.; Hanus, L.; Ligumsky, M.; Kaminsky,
N. E.; Schatz, A. R.; Gopher, A.; Almog, S.; Martin, B. R.; Compton, D. R.;
Pertwee, R. G.; Griffin, G.; Bayewitch, M.; Barg, J.; Vogel, Z. Biochem.
Pharmacol. 1995, 50, 83; (b) Sugiura, T.; Kondo, S.; Sukagawa, A.;
Nakane, S.; Shinoda, A.; Itoh, K.; Yamashita, A.; Waku, K. Biochem.
Biophys. Res. Commun. 1995, 215, 89; (c) Stella, N.; Schweitzer, P.;
Piomelli, D. Nature 1997, 388, 773.
( )7
( )5
28
NH2
( )7
( )5
29
NH2
NH2.HCl
NHBoc
Scheme 4. Synthesis of carboxamide 29. Reagents: (a) Boc2O, Et3N, MeOH; (b) DCC,
HOBt, 25% aq:NH3, CH2Cl2, DMF; (c) 4N HCl=Et2O.

V. Magrioti et al. / Bioorg. Med. Chem. Lett. 18 (2008) 5424–5427
5427
4. (a) Sugiura, T.; Kodaka, T.; Nakane, S.; Miyashita, T.; Kondo, S.; Suhara, Y.;
17. Guindon, J.; Desroches, J.; Beaulieu, P. Br. J. Pharmacol. 2007, 150, 693.
18. Hohmann, A. G. Br. J. Pharmacol. 2007, 150, 673.
19. Kokotos, G.; Verger, R.; Chiou, A. Chem. Eur. J. 2000, 6, 4211.
Takayama, H.; Waku, K.; Seki, C.; Baba, N.; Ishima, Y. J. Biol. Chem. 1999, 274,
2794; (b) Gonsiorek, W.; Lunn, C.; Fan, X.; Narula, S.; Lyndell, D.; Hipkin, R. W.
Mol. Pharmacol. 2000, 57, 1045.
20. Kotsovolou, S.; Chiou, A.; Verger, R.; Kokotos, G. J. Org. Chem. 2001, 66, 962.
21. Chiou, A.; Verger, R.; Kokotos, G. Lipids 2001, 36, 535.
22. Kokotos, G.; Kotsovolou, S.; Verger, R. ChemBioChem 2003, 4, 101.
23. Kokotos, G.; Kotsovolou, S.; Six, D. A.; Constantinou-Kokotou, V.; Beltzner, C. C.;
Dennis, E. A. J. Med. Chem. 2002, 45, 2891.
24. Kokotos, G.; Six, D. A.; Loukas, V.; Smith, T.; Constantinou-Kokotou, V.;
Hadjipavlou-Litina, D.; Kotsovolou, S.; Chiou, A.; Beltzner, C. C.; Dennis, E. A. J.
Med. Chem. 2004, 47, 3615.
25. Stephens, D.; Barbayianni, E.; Constantinou-Kokotou, V.; Peristeraki, A.; Six, D.
A.; Cooper, J.; Harkewicz, R.; Deems, R. A.; Dennis, E. A.; Kokotos, G. J. Med.
Chem. 2006, 49, 2821.
26. Yaksh, T. L.; Kokotos, G.; Svensson, C. I.; Stephens, D.; Kokotos, C. G.;
Fitzsimmons, B.; Hadjipavlou-Litina, D.; Hua, X.-Y.; Dennis, E. A. J. Pharmacol.
Exp. Ther. 2006, 316, 466.
5. (a) Piomelli, D. Curr. Opin. Investig. Drugs 2005, 6, 672; (b) Di Marzo, V.; Bifulco,
M.; De Petrocallis, L. Nat. Rev. Drug Disc. 2004, 3, 771; (c) Makriyannis, A.;
Mechoulam, R.; Piomelli, D. Neuropharmacology 2005, 48, 1068; (d) Bahr, B. A.;
Karanian, D. A.; Makanji, S. S.; Makriyannis, A. Expert Opin. Investig. Drugs 2006,
15, 351.
6. (a) Desarnaud, F.; Cadas, H.; Piomelli, D. J. Biol. Chem. 1995, 270, 6030; (b) Ueda,
N.; Kurahashi, Y.; Yamamoto, S.; Tokunaga, T. J. Biol. Chem. 1995, 270, 23823;
(c) Cravatt, B. F.; Giang, D. K.; Mayfield, S. P.; Boger, D. L.; Lerner, R. A.; Gilula, N.
B. Nature 1996, 384, 83; (d) Goparaju, S. K.; Ueda, N.; Yamaguchi, H.;
Yamamoto, S. FEBS Lett. 1998, 422, 69; (e) Lang, W.; Qin, C.; Lin, S.;
Khanolkar, A. D.; Goutopoulos, A.; Fan, P.; Abouzid, K.; Meng, Z.; Biegel, D.;
Makriyannis, A. J. Med. Chem. 1999, 42, 896.
7. (a) Tornquist, H.; Belfrage, P. J. Biol. Chem. 1976, 251, 813; (b) Karlsson, M.;
Contreras, J. A.; Hellman, U.; Tornqvist, H.; Holm, C. J. Biol. Chem. 1997, 272,
27218.
27. Magrioti, V.; Hadjipavlou-Litina, D.; Constantinou-Kokotou, V. Bioorg. Med.
Chem. Lett. 2003, 13, 375.
8. Dinh, T. P.; Carpenter, D.; Leslie, F. M.; Freund, T. F.; Katona, I.; Sensi, S. L.;
Kathuria, S.; Piomelli, D. Proc. Natl. Acad. Sci. U.S.A. 2002, 99, 10819.
9. Dinh, T. P.; Kathuria, S.; Piomelli, D. Mol. Pharmacol. 2004, 66, 1260.
10. Zvonok, N.; Pandarinathan, L.; Williams, J.; Johnston, M.; Karageorgos, I.;
Janero, D. R.; Krishnan, S. C.; Makriyannis, A. Chem. Biol. 2008, 15, 854.
11. For selected references, see: (a) Leung, D.; Du, W.; Hardouin, C.; Cheng, H.;
Hwang, I.; Cravatt, B. F.; Boger, D. L. Bioorg. Med. Chem. Lett. 2005, 15, 1423; (b)
Boger, D. L.; Miyauchi, H.; Du, W.; Hardouin, C.; Fecik, R. A.; Cheng, H.; Hwang,
I.; Hedrick, M. P.; Leung, D.; Acevedo, O.; Guimarães, C. R. W.; Jorgensen, W. L.;
Cravatt, B. F. J. Med. Chem. 2005, 48, 1849; (c) Romero, F. A.; Du, W.; Hwang, I.;
Rayl, T. J.; Kimball, F. S.; Leung, D.; Hoover, H. S.; Apodaca, R. L.; Breitenbucher,
J. G.; Cravatt, B. F.; Boger, D. L. J. Med. Chem. 2007, 50, 1058; (d) Hardouin, C.;
Kelso, M. J.; Romero, F. A.; Rayl, T. J.; Leung, D.; Hwang, I.; Cravatt, B. F.; Boger,
D. L. J. Med. Chem. 2007, 50, 3359.
28. Kokotos, G.; Constantinou-Kokotou, V.; del Olmo Fernandez, E.; Toth, I.;
Gibbons, W. A. Liebigs Ann. Chem. 1992, 961.
29. Markidis, T.; Kokotos, G. J. Org. Chem. 2001, 66, 1919.
30. All new compounds were fully characterized by 1H and [13]C NMR, MS and
elemental analysis. Selected data of final inhibitor: Compound 21: Waxy solid;
½
a 2D5
ꢃ
ꢀ8.3 (c = 0.7, CH3OH); 1H NMR (200MHz, CD3OD) d 0.90 (t, J = 5.2Hz, 3H,
CH3Þ, 1.29 (br s, 8H, 4ꢂ CH2Þ, 1.39 (br s, 12H, 6ꢂ CH2Þ, 1.72 (m, 2H, CH2CH),
2.04 (m, 4H, CH2CH ¼ CHCH2Þ, 3.32–3.23 (m, 2H, CH2NH2Þ, 3.52 (m, 1H, CH),
5.35 (m, 2H, CH@CH); 13C NMR (50MHz, CD3OD): d 14.5, 23.7, 26.0, 28.1, 30.1,
30.3, 30.4, 30.4, 30.6, 30.8, 30.9, 31.7, 39.1, 42.2, 50.9, 130.6, 131.0; MS (ESI) m/
z (%) 283.2 (MHþ, 100).
31. (a) Constantinou-Kokotou, V.; Magrioti, V.; Markidis, T.; Kokotos, G. J. Pept.
Res. 2001, 58, 325; (b) Magrioti, V.; Constantinou-Kokotou, V. Lipids 2002,
37, 223.
12. Saario, S. M.; Savinainen, J. R.; Laitinen, J. T.; Jarvinen, T.; Niemi, R. Biochem.
Pharmacol. 2004, 67, 1381.
13. Saario, S. M.; Salo, O. M. H.; Nevalainen, T.; Poso, A.; Laitinen, J. T.; Jarvinen, T.;
Niemi, R. Chem. Biol. 2005, 12, 649.
14. Ghafouri, N.; Tiger, G.; Razdan, R. K.; Mahadevan, A.; Pertwee, R. G.; Martin, B.
R.; Fowler, C. J. Br. J. Pharmacol. 2004, 143, 774.
15. Makara, J. K.; Mor, M.; Fegley, D.; Szabo, S. I.; Kathuria, S.; Astarita, G.; Duranti,
A.; Tontini, A.; Tarzia, G.; Rivara, S.; Freund, T. F.; Piomelli, D. Nat. Neurosci.
2005, 8, 1139.
32. Magrioti, V.; Verger, R.; Constantinou-Kokotou, V. J. Med. Chem. 2004, 47, 288.
33. Lang, W.; Qin, C.; Hill, W. A. G.; Lin, S.; Khanolkar, A. D.; Makriyannis, A. . Anal.
Biochem. 1996, 238, 40.
34. Lang, W.; Qin, C.; Lin, S.; Khanolkar, A. D.; Goutopoulos, A.; Fan, P.; Abouzid, K.;
Meng, Z.; Biegel, D.; Makriyannis, A. J. Med. Chem. 1999, 42, 896.
35. Qin, C.; Lin, S.; Lang, W.; Goutopoulos, A.; Pavlopoulos, S.; Mauri, F.;
Makriyannis, A. Anal. Biochem. 1998, 261, 8.
36. Vadivel, S. K.; Vardarajan, S.; Duclos, R. I., Jr.; Wood, J. T.; Guo, J.; Makriyannis,
A. Bioorg. Med. Chem. Lett. 2007, 17, 5959.
16. (a) Saario, S. M.; Palomaki, V.; Lehtonen, M.; Nevalainen, T.; Jarvinen, T.;
Laitinen, J. T. Chem. Biol. 2006, 13, 811; (b) Vandevoorde, S.; Jonsson, K.-O.;
Labar, G.; Persson, E.; Lambert, D. M.; Fowler, C. J. Br. J. Pharmacol. 2007, 150,
186.
37. Bisogno, T.; Cascio, M. G.; Saha, B.; Mahadevan, A.; Urbani, P.; Minassi, A.;
Appendino, G.; Saturino, C.; Martin, B.; Razdan, R.; Di Marzo, V. Biochim.
Biophys. Acta 2006, 1761, 205.