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Journal of Natural Products Aug 2022The kernels of the Australian blushwood tree () are the source of the veterinary anticancer drug tigilanol tiglate (, Stelfonta) and contain a concentration of phorboids... (Review)
Review
The kernels of the Australian blushwood tree () are the source of the veterinary anticancer drug tigilanol tiglate (, Stelfonta) and contain a concentration of phorboids significantly higher than croton oil, the only abundant source of these compounds previously known. The oily matrix of the blushwood kernels is composed of free fatty acids and not by glycerides as found in croton oil. By active partitioning, it was therefore possible to recover and characterize for the first time a cryptic tigliane fraction, that is, the diterpenoid fraction that, because of its lipophilicity, could not be obtained by solvent partition of crude extracts. The cryptic tigliane fraction accounted for ca. 30% of the tigliane kernel titer and was quantified by H NMR spectroscopy and profiled by HPLC-MS. Long-chain (linoleates and/or oleates) 20-acyl derivatives of the epoxytigliane diesters tigilanol tiglate (EBC-46, ), EBC-47 (), EBC-59 (), EBC-83 (), and EBC-177 () were identified. By chemoselective acylation of EBC-46 () and EBC-177 () the natural triesters and and a selection of analogues were prepared to assist identification of the natural compounds. The presence of a free C-20 hydroxy group is a critical requirement for PKC activation by phorbol esters. The unexpected activity of 20-linoleoyl triester in a cytotoxicity assay based on PKC activation was found to be related mainly to its hydrolysis to tigilanol tiglate () under the prolonged conditions of the assay, while other esters were inactive. Significant differences between the esterification profile of the epoxytigliane di- and triesters exist in , suggesting a precise, yet elusive, blueprint of acyl decoration for the tigliane polyol 5-hydroxyepoxyphorbol.
Topics: Australia; Croton Oil; Euphorbiaceae; Phorbols; Trees
PubMed: 35973043
DOI: 10.1021/acs.jnatprod.2c00226 -
Journal of Natural Products Dec 2020During a chemical investigation of , three new [wikstrocins A-C (-)] and three known tigliane diterpenoids (-) were isolated. The structures of the new compounds were...
During a chemical investigation of , three new [wikstrocins A-C (-)] and three known tigliane diterpenoids (-) were isolated. The structures of the new compounds were elucidated from extensive physiochemical and spectroscopic analysis. The correlations between the ECD Cotton effects and B ring structures of tiglianes were also evaluated. The isolated compounds were assessed for their anti-HIV activity against HIV-1 infection of MT4 cells, and two compounds ( and ) showed potent anti-HIV activity with IC values of 3.8 and 12.8 nM, respectively.
Topics: Anti-HIV Agents; Cell Line; Diterpenes; Humans; Phorbols; Spectrum Analysis; Wikstroemia
PubMed: 33172265
DOI: 10.1021/acs.jnatprod.0c00700 -
Journal of Natural Medicines Sep 2023Tigliane and daphnane diterpenoids are characteristically distributed in plants of the Thymelaeaceae family as well as the Euphorbiaceae family and are structurally... (Review)
Review
Tigliane and daphnane diterpenoids are characteristically distributed in plants of the Thymelaeaceae family as well as the Euphorbiaceae family and are structurally diverse due to the presence of polyoxygenated functionalities in the polycyclic skeleton. These diterpenoids are known as toxic components, while they have been shown to exhibit a wide variety of biological activities, such as anti-cancer, anti-HIV, and analgesic activity, and are attracting attention in the field of natural product drug discovery. This review focuses on naturally occurring tigliane and daphnane diterpenoids from plants of the Thymelaeaceae family and provides an overview of their chemical structure, distribution, isolation, structure determination, chemical synthesis, and biological activities, with a prime focus on the recent findings.
Topics: Phorbols; Thymelaeaceae; Diterpenes; Drug Discovery; Molecular Structure
PubMed: 37294498
DOI: 10.1007/s11418-023-01713-x -
Phytochemistry Jun 2020Bioassay-guided fractionation of the n-butanol extract from the branches and leaves of Reutealis trisperma resulted in the isolation of six undescribed (crotignoids...
Bioassay-guided fractionation of the n-butanol extract from the branches and leaves of Reutealis trisperma resulted in the isolation of six undescribed (crotignoids L ~ Q) together with two known (12-deoxyphorbol-13-hexadecanoate and 12-deoxyphorbol-13-myristate) tigliane diterpenoids. Their structures, especially the absolute configurations, were determined from extensive spectroscopic studies, including 2D NMR spectra, CD data analysis and electronic circular dichroism (ECD) calculations. All isolates were tested for anti-HIV activity against HL4-3 virus in MT4 cells. Except for crotignoid Q, the remaining seven tigliane diterpenoids exhibited potent anti-HIV activity with IC values ranging from 0.0023 to 4.03 μM.
Topics: Diterpenes; Drugs, Chinese Herbal; Euphorbiaceae; Molecular Structure; Phorbols
PubMed: 32229336
DOI: 10.1016/j.phytochem.2020.112360 -
Nature Apr 2016Phorbol, the flagship member of the tigliane diterpene family, has been known for over 80 years and has attracted attention from many chemists and biologists owing to...
Phorbol, the flagship member of the tigliane diterpene family, has been known for over 80 years and has attracted attention from many chemists and biologists owing to its intriguing chemical structure and the medicinal potential of phorbol esters. Access to useful quantities of phorbol and related analogues has relied on isolation from natural sources and semisynthesis. Despite efforts spanning 40 years, chemical synthesis has been unable to compete with these strategies, owing to its complexity and unusual placement of oxygen atoms. Purely synthetic enantiopure phorbol has remained elusive, and biological synthesis has not led to even the simplest members of this terpene family. Recently, the chemical syntheses of eudesmanes, germacrenes, taxanes and ingenanes have all benefited from a strategy inspired by the logic of two-phase terpene biosynthesis in which powerful C-C bond constructions and C-H bond oxidations go hand in hand. Here we implement a two-phase terpene synthesis strategy to achieve enantiospecific total synthesis of (+)-phorbol in only 19 steps from the abundant monoterpene (+)-3-carene. The purpose of this synthesis route is not to displace isolation or semisynthesis as a means of generating the natural product per se, but rather to enable access to analogues containing unique placements of oxygen atoms that are otherwise inaccessible.
Topics: Bicyclic Monoterpenes; Biological Products; Chemistry Techniques, Synthetic; Diterpenes; Molecular Structure; Monoterpenes; Oxygen; Phorbol Esters; Phorbols; Stereoisomerism
PubMed: 27007853
DOI: 10.1038/nature17153 -
Genetics Jul 2022Activated Gαq signals through phospholipase-Cβ and Trio, a Rho GTPase exchange factor (RhoGEF), but how these distinct effector pathways promote cellular responses to...
Activated Gαq signals through phospholipase-Cβ and Trio, a Rho GTPase exchange factor (RhoGEF), but how these distinct effector pathways promote cellular responses to neurotransmitters like serotonin remains poorly understood. We used the egg-laying behavior circuit of Caenorhabditis elegans to determine whether phospholipase-Cβ and Trio mediate serotonin and Gαq signaling through independent or related biochemical pathways. Our genetic rescue experiments suggest that phospholipase-Cβ functions in neurons while Trio Rho GTPase exchange factor functions in both neurons and the postsynaptic vulval muscles. While Gαq, phospholipase-Cβ, and Trio Rho GTPase exchange factor mutants fail to lay eggs in response to serotonin, optogenetic stimulation of the serotonin-releasing HSN neurons restores egg laying only in phospholipase-Cβ mutants. Phospholipase-Cβ mutants showed vulval muscle Ca2+ transients while strong Gαq and Trio Rho GTPase exchange factor mutants had little or no vulval muscle Ca2+ activity. Treatment with phorbol 12-myristate 13-acetate that mimics 1,2-diacylglycerol, a product of PIP2 hydrolysis, rescued egg-laying circuit activity and behavior defects of Gαq signaling mutants, suggesting both phospholipase-C and Rho signaling promote synaptic transmission and egg laying via modulation of 1,2-diacylglycerol levels. 1,2-Diacylglycerol activates effectors including UNC-13; however, we find that phorbol esters, but not serotonin, stimulate egg laying in unc-13 and phospholipase-Cβ mutants. These results support a model where serotonin signaling through Gαq, phospholipase-Cβ, and UNC-13 promotes neurotransmitter release, and that serotonin also signals through Gαq, Trio Rho GTPase exchange factor, and an unidentified, phorbol 12-myristate 13-acetate-responsive effector to promote postsynaptic muscle excitability. Thus, the same neuromodulator serotonin can signal in distinct cells and effector pathways to coordinate activation of a motor behavior circuit.
Topics: Animals; Caenorhabditis elegans; Calcium; Diglycerides; GTP-Binding Proteins; Myristates; Neurotransmitter Agents; Phorbols; Phospholipases; Rho Guanine Nucleotide Exchange Factors; Serotonin; rho GTP-Binding Proteins
PubMed: 35579369
DOI: 10.1093/genetics/iyac084 -
Toxicology in Vitro : An International... Dec 2022Establishing the functionality, reproducibility, robustness, and reliability of microphysiological systems is a critical need for adoption of these technologies. A high...
Analysis of reproducibility and robustness of OrganoPlate® 2-lane 96, a liver microphysiological system for studies of pharmacokinetics and toxicological assessment of drugs.
Establishing the functionality, reproducibility, robustness, and reliability of microphysiological systems is a critical need for adoption of these technologies. A high throughput microphysiological system for liver studies was recently proposed in which induced pluripotent stem cell-derived hepatocytes (iHeps) and non-parenchymal cells (endothelial cells and THP-1 cells differentiated with phorbol 12-myristate 13-acetate into macrophage-like cells) were co-cultured in OrganoPlate® 2-lane 96 devices. The goal of this study was to evaluate this platform using additional cell types and conditions and characterize its utility and reproducibility. Primary human hepatocytes or iHeps, with and without non-parenchymal cells, were cultured for up to 17 days. Image-based cell viability, albumin and urea secretion into culture media, CYP3A4 activity and drug metabolism were assessed. The iHeps co-cultured with non-parenchymal cells demonstrated stable cell viability and function up to 17 days; however, variability was appreciable both within and among studies. The iHeps in monoculture did not form clusters and lost viability and function over time. The primary human hepatocytes in monoculture also exhibited low cell viability and hepatic function. Metabolism of various drugs was most efficient when iHeps were co-cultured with non-parenchymal cells. Overall, we found that the OrganoPlate® 2-lane 96 device, when used with iHeps and non-parenchymal cells, is a functional liver microphysiological model; however, the high-throughput nature of this model is somewhat dampened by the need for replicates to compensate for high variability.
Topics: Humans; Reproducibility of Results; Cells, Cultured; Cytochrome P-450 CYP3A; Endothelial Cells; Myristates; Hepatocytes; Liver; Albumins; Urea; Culture Media; Acetates; Phorbols
PubMed: 36057418
DOI: 10.1016/j.tiv.2022.105464 -
Journal of Natural Products Dec 2023To investigate the role of the secondary 5-hydroxy group in the activity of the anticancer drug tigilanol tiglate () (Stelfonta), oxidation of this epoxytigliane...
To investigate the role of the secondary 5-hydroxy group in the activity of the anticancer drug tigilanol tiglate () (Stelfonta), oxidation of this epoxytigliane diterpenoid from the Australian rainforest plant was attempted. Eventually, 5-dehydrotigilanol tiglate () proved too unstable to be characterized in terms of biological activity and, therefore, was not a suitable tool compound for bioactivity studies. On the other hand, a series of remarkable skeletal rearrangements associated with the presence of a 5-keto group were discovered during its synthesis, including a dismutative ring expansion of ring A and a mechanistically unprecedented dyotropic substituent swap around the C-4/C-10 bond. Taken together, these observations highlight the propensity of the α-hydroxy-β-diketone system to trigger complex skeletal rearrangements and pave the way to new areas of the natural products chemical space.
Topics: Phorbols; Australia; Diterpenes; Antineoplastic Agents; Biological Products
PubMed: 37991924
DOI: 10.1021/acs.jnatprod.3c00834 -
Journal of Cancer Research and Clinical... Aug 2017In 1988, we first reported the complete chemical structure of a new type of phorbol ester, abbreviated to DHPB, found in seed oil of Jatropha curcas L. (Saboodam in... (Review)
Review
PURPOSE
In 1988, we first reported the complete chemical structure of a new type of phorbol ester, abbreviated to DHPB, found in seed oil of Jatropha curcas L. (Saboodam in Thai) and its tumor-promoting activity on mouse skin. Although this seed oil contains toxic phorbol ester, it was planned to use it as a feasible renewable oil and the extracted seed cake as fertilizer. This utilization value opened a new science of Jatropha curcas.
METHODS
The main experimental results are cited from our publications, and the relevant literature screened from journals and PubMed.
RESULTS AND DISCUSSION
This paper begins with our original work on the structural elucidation of a new phorbol ester, 12-deoxy-16-hydroxyphorbol (DHPB): its tumor-promoting activity was compared with that of TPA. We think that it is timely to review the following research advances with Jatropha curcas, so numerous topics are classified as follows: (1) historical development of phorbol esters in seed oil; (2) toxicity of phorbol ester based on various bioassays; (3) degradation of phorbol ester; (4) a new pharmaceutical compound in seed; and (5) tumor promotion and progression with endogeneous tumor promoters in human carcinogenesis. The discovery of phorbol ester in seed oil raised awareness of the danger of public use of seed oil and seed cake in Thailand, and also indicated the necessity of discussing the concept of primary and tertiary cancer preventions.
CONCLUSION
It is worthwhile to study the future benefits and cancer risks of globally distributed Jatropha curcas L.
Topics: Carcinogenesis; Humans; Jatropha; Neoplasms; Phorbol Esters; Plant Oils; Seeds
PubMed: 28124725
DOI: 10.1007/s00432-017-2341-6 -
Fish & Shellfish Immunology Nov 2022The aim of this study was the induction and characterization of extracellular traps (ETs) produced by gilthead seabream (Sparus aurata L.) head-kidney leucocytes. The...
The aim of this study was the induction and characterization of extracellular traps (ETs) produced by gilthead seabream (Sparus aurata L.) head-kidney leucocytes. The cells were incubated several times (10, 30, 60, 120, and 180 min) with different concentrations of the stimulants diluted in RPMI-1640 culture medium: RPMI-1640 (control), β-glucan from Saccharomyces cerevisiae (BG, 0-400 μg mL), lipopolysaccharide from Escherichia coli (LPS, 0-10 μg mL), calcium ionophore A23187 (CaI, 0-5 μg mL), Phorbol 12-myristate 13-acetate (PMA, 0-1000 ng mL) and polyinosinic-polycytidylic acid sodium salt (Poly I:C, 0-200 μg mL). BG, LPS and CaI exerted only weak stimulatory activity, while PMA and poly I:C exerted a potent one. After stimulation of the leucocytes, ETs structures were quantified and visualised through staining of the chromatin with nucleic acid-specific dyes and immunocytochemical probing of characteristic proteins expected to decorate the structure. ETs structures had DNA and myeloperoxidase. The ETs morphology was studied by light and scanning electron microscopy. These data confirm that seabream leucocytes form ETs with different morphological properties, depending on the used stimulant. These results will be the basis for new studies to analyse the implication of this mechanism in fish immunity. All this new knowledge will have its application in fish farms when we learn to manipulate the innate immune response in order to mitigate microbial infections.
Topics: Acetates; Animals; Calcimycin; Calcium Ionophores; Chromatin; Coloring Agents; Extracellular Traps; Kidney; Leukocytes; Lipopolysaccharides; Myristates; Nucleic Acids; Peroxidase; Phorbols; Poly I-C; Sea Bream; Sodium; beta-Glucans
PubMed: 36152801
DOI: 10.1016/j.fsi.2022.09.045