- Antischistosomal Properties of Sclareol and Its Heck-Coupled Derivatives: Design, Synthesis, Biological Evaluation, and Untargeted Metabolomics
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Sclareol, a plant-derived diterpenoid widely used as a fragrance and flavoring substance, is well-known for its promising antimicrobial and anticancer properties. However, its activity on helminth parasites has not been previously reported. Here, we show that sclareol is active against larval (IC50 ≈ 13 μM), juvenile (IC50 = 5.0 μM), and adult (IC50 = 19.3 μM) stages of Schistosoma mansoni, a parasitic trematode responsible for the neglected tropical disease schistosomiasis. Microwave-assisted synthesis of Heck-coupled derivatives improved activity, with the substituents choice guided by the Matsy decision tree. The most active derivative 12 showed improved potency and selectivity on larval (IC50 ≈ 2.2 μM, selectivity index (SI) ≈ 22 in comparison to HepG2 cells), juvenile (IC50 = 1.7 μM, SI = 28.8), and adult schistosomes (IC50 = 9.4 μM, SI = 5.2). Scanning electron microscopy studies revealed that compound 12 induced blebbing of the adult worm surface at sublethal concentration (12.5 μM); moreover, the compound inhibited egg production at the lowest concentration tested (3.13 μM). The observed phenotype and data obtained by untargeted metabolomics suggested that compound 12 affects membrane lipid homeostasis by interfering with arachidonic acid metabolism. The same methodology applied to praziquantel (PZQ)-treated worms revealed sugar metabolism alterations that could be ascribed to the previously reported action of PZQ on serotonin signaling and/or effects on glycolysis. Importantly, our data suggest that compound 12 and PZQ exert different antischistosomal activities. More studies will be necessary to confirm the generated hypothesis and to progress the development of more potent antischistosomal sclareol derivatives.
- Crusco, Alessandra,Whiteland, Helen,Baptista, Rafael,Forde-Thomas, Josephine E.,Beckmann, Manfred,Mur, Luis A. J.,Nash, Robert J.,Westwell, Andrew D.,Hoffmann, Karl F.
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p. 1188 - 1199
(2019/06/08)
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- A short and efficient synthesis of (+)-totarol
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A concise route to multigram quantities of the antibacterial diterpene (+)-totarol (1) is reported. (-)-Sclareol (2) was converted to the target compound 1 using either a six- or a seven-step sequence, while only three steps were required to access (+)-totarol ( 1) starting from (+)-manool (9) or (+)-13-epi-manool (10), respectively. A novel one-pot intramolecular aldol condensation/α-alkylation protocol served as the key operation for streamlining the syntheses of 1. ARKAT-USA, Inc.
- Rogachev, Victor,Loehl, Thorsten,Markert, Thomas,Metz, Peter
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p. 172 - 180
(2013/09/24)
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- Substrate specificity of Rv3378c, an enzyme from Mycobacterium tuberculosis, and the inhibitory activity of the bicyclic diterpenoids against macrophage phagocytosis
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The Rv3378c gene product from Mycobacterium tuberculosis encodes a diterpene synthase to produce tuberculosinol (3), 13R-isotuberculosinol (4a), and 13S-isotuberculosinol (4b) from tuberculosinyl diphosphate (2). The product distribution ratios are 1:1 for 3 to 4 and 1:3 for 4a to 4b. The substrate specificity of the Rv3378c-encoded enzyme was examined. The 3 labdadienyl diphosphates, copalyl diphosphate (CDP) (7), ent-CDP (8), and syn-CDP (9), underwent the conversion reaction, with good yields (67-78%). Copalol (23) and manool (24) were produced from 7, ent-copalol (25) and ent-manool (26) from 8, and syn-copalol (27) and vitexifolin A (28) from 9. The ratio of 23 to 24 was 40:27, that of 25:26 was 22:50, and that of 27:28 was 16:62. Analysis on a GC-MS chromatograph equipped with a chiral column revealed that 24, 26, and 28 consisted of a mixture of 13R- (a) and 13S-stereoisomers (b) in the following ratio: ca. 1:1 for 24a to 24b, ca. 1:5 for 26a to 26b, and ca. 1:19 for 28a to 28b. The structures of these products indicate that the reactions of the 3 CDPs proceeded in the same fashion as that of 2. This is the first report on the enzymatic synthesis of natural diterpenes manool, ent-manool, and vitexifolin A. Both Rv3377c and Rv3378c genes are found in virulent Mycobacterium species, but not in avirulent species. We found that 3 and 4 inhibited the phagocytosis of opsonized zymosan particles by human macrophage-like cells. Interestingly, the inhibitory activity was synergistically increased by the coexistence of 3 and 4b. Other labdane-related diterpenes, 13-16 and 23-28, had little or no inhibitory activity. This synergistic inhibition by 3 and 4 may provide further advantage to the impairment of phagocyte function, which might contribute to pathogenicity of M. tuberculosis.
- Hoshino, Tsutomu,Nakano, Chiaki,Ootsuka, Takahiro,Shinohara, Yosuke,Hara, Takashi
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experimental part
p. 2156 - 2165
(2011/05/14)
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- Oxidation studies on 8(17),14-labdadien-3R,13R-diol: A major diterpene of Juniperus pseudosabina Hook
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The renewable foerest biomass of Juniperus pseudosabina Hook after steam distillation and extraction afford several labdanes including 8(17),14-labdadien-3R,13R-diol (1), as a major natural product.The oxidation products of 1, particularly 14,15-dinor labdanes are being reported here, which could be a good starting material for fragrance chemicals of ambergris type.
- Agarwal, S. G.,Thappa, R. K.,Dhar, K. L.
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p. 669 - 671
(2007/10/03)
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- TERPENOIDS AND STEROLS FROM THE WOOD OF ABIES PINSAPO
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From the neutral fraction of the hexane extract of the wood of Abies pinsapo 11 sesquiterpenoids, seven diterpenoids, three triterpenoids and two sterols have been identified.Three of them are new natural products: 3β-hydroxy-13-epimanool, (23R,25R)-3α-methoxy-9,19-cyclo-9β-lanostan-26,23-olide and (22S)-5α-ergostane-3α,22-diol.Their structure were established by spectroscopic methods and chemical correlations. Key words: Abies pinsapo; Pinaceae; wood; labdane diterpenoids; cyclolanostanolides; sterols.
- Barrero, Alejandro,Sanchez, Juan F.,Alvarez-Manzaneda, E. J.,Dorado, M. Munoz,Haidour, Ali
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p. 1261 - 1266
(2007/10/02)
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- Seven New Labdane Diterpenes from Juniperus pseudosabina Hook
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The aerial parts (leaves and twigs) of Juniperus pseudosabina Hook afford, in addition to three known, seven new diterpenes of labdane type.Absolute stereostructures of the new diterpenes have been established based on spectroscopic (IR, PMR, CMR and mass) and chemical evidences (including partial synthesis where necessary).
- Pandita, K.,Agarwal, S. G.,Thappa, R. K.,Dhar, K. L.
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p. 453 - 458
(2007/10/02)
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- Plasmid-determined Transformation of cis Abienol and Sclareol in Nocardia restricta JTS-162
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The cis-abienol-transformable bacterium JTS-162 was identified as Nocardia restricta.This bacterium has three plasmids (pCA1, pCA2 and pCA3).Two types of cured strains were obtained by mitomicin C treatment or growth at the maximum temperature; one type had two plasmids (pCA2 and pCA3) and the other type had no plasmid.These two types of cured strains lost the ability to oxidize C-18 methyl and to split the A-ring of cis-abienol.These two types of cured strains were also devoid of the ability to oxidize the C-18 methyl of sclareol.From these results, it was considered that C-18 methyl oxidation and A-ring splitting of these labdanes were determined by plasmid pCA1 in N. restricta JTS-162.
- Hieda, Tadaharu,Mikami, Yoichi,Obi, Yukiteru,Kisaki, Takuro
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p. 3055 - 3062
(2007/10/02)
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- Photosensitized Oxygenation of Labda-8(17),12-diene, Labda-8(17),13-diene, and the Biformenes. Synthesis of Pumiloxide
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Reactions of the title compounds with singlet oxygen were studied.In labda-8(17),12-diene (2; 7:3 mixture of E and Z isomers), syn addition leading to 7 (58percent) was predominant.Smaller amounts of 8 (20percent) by syn addition to (E)-2 or anti addition to (Z)-2, 9 (5percent), 10 (2,5percent), and 11(1.5percent) were also formed. (E)-Labda-8(17),13-diene ((E)-3) gave 29percent 12 and 40percent 13 by syn addition, whereas (Z)-3 gave 57percent 12 by syn addition and 19percent 13 by anti addition.In trans-biformene (5) syn attack at C-12 to give 15 (27percent), 16 (10percent), 18 (12percent), and 19 (4percent) was greatly preferred to syn attack at C-13 to give 17 (6percent).In cis-biformene (6) syn attack at C-13 to give 17 (39percent) predominated slightly over anti attack at C-12 to give 15 (13percent), 16 (8percent), 18 (4percent), and 19 (4percent).Diels-Alder reactions with singlet oxygen leading to epidioxides 20 and 21 were relatively unimportant (7percent from 5, 5percent from 6).The epidioxides were converted to the naturally occurring furanolabdane pumiloxide (22).
- Mohanraj, Subramaniam,Herz, Werner
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p. 1362 - 1366
(2007/10/02)
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