Fatty Acyl Derivatives Research Articles

Exploring the broad-spectrum pharmacological activity of two less studied Australian native fruits: chemical characterisation using LCMS-driven metabolomics.

Australian fruits such as native currant (Acrotriche depressa) and lemon aspen (Acronychia acidula) are under-examined in terms of their therapeutic potential. In this study, the in vitro antiproliferative activity of native currant and lemon aspen extracts (water and ethanol) against MCF7 breast adenocarcinoma cells was determined using the Alamar blue assay. The most potent extracts (native currant water, NC-W; native currant ethanol, NC-Et; lemon aspen ethanol, LA-Et) were further evaluated using flow cytometry to detect the potential induction of apoptosis in MCF7 cells whereas 2',7'-dichlorodihydrofluorescein diacetate (H2DCFDA) assay was implemented to understand the impact of the extracts on the intracellular reactive oxygen species (ROS) levels in MCF7 cells. Furthermore, the antioxidant activity of the extracts was assessed using ABTS [2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonate)], and CUPRAC (cupric reducing antioxidant capacity) assays. The antimicrobial susceptibility testing of NC-W, NC-Et, and LA-Et was carried out against Gram-positive (Staphylococcus aureus), Gram-negative (Escherichia coli), and yeast (Candida albicans) strains using a resazurin-based assay. Additionally, potential metabolites in the NC-W and NC-Et extracts were analysed with liquid chromatography-mass spectrometry (LC-MS) driven metabolomics and chemometrics to spot differential and major metabolites. A dose-dependent antiproliferative activity was conferred by the NC extracts against MCF7 cells. Of the two LA extracts, only LA-Et showed a dose-dependent antiproliferative activity at higher concentrations. Both NC extracts and LA-Et induced apoptosis in MCF7 cells. None of the extracts increased the production of ROS significantly in MCF7 cells compared to the untreated control. A dose-dependent antioxidant activity was observed in both antioxidant assays. Both NC and LA extracts showed a similar minimum inhibitory concentration (MIC) value against S. aureus. Only LA-Et showed activity against E. coli, while NC-W and NC-Et were less active. All extracts showed MIC values of >1500 μg mL-1 against C. albicans. The metabolomics analysis revealed an abundance of flavonoids, fatty acyl derivatives, carbohydrates, carboxylic acids and their derivatives, and alkaloid compounds as potential bioactive metabolites in the NC extracts. In conclusion, both NC and LA showed antiproliferative (against MCF7 breast adenocarcinoma cells through the induction of apoptosis), strong antioxidant and minimal antimicrobial properties.

Angiotensin(1-7)-Stearic Acid Conjugate: Synthesis and Characterization

The novel coronavirus, SARS-CoV-2, broken out as the COVID-19 epidemic, is transported into the cytoplasm by angiotensin-converting enzyme-2 (ACE2), a key protein of the renin-angiotensin-system (RAS). ACE2 is a protective protein that reduces angiotensin (Ang) II, the bioactive component of RAS, by converting it to its potent antagonist, Ang-(1-7) peptide, in order to provide a pathophysiological response to stimuli. Although ACE-2 is upregulated especially in pulmonary endothelial cells and alveolar epithelial cells, downregulation of ACE-2 in the lung owing to loss of key regulatory factors explains the enzyme-dependent lethality of SARS-CoV-2. The N-terminal domain (NTD) of S1, one of the protein subunits of coronaviruses, is known to recognize acetylated sialic acids on glycosylated cell surface receptors. In this study, the stearic acid-peptide conjugate mimicking the sialic acid structure was synthesized, which will be able to balance uncontrolled inflammatory response and excessive cytokine production, and depending on these to suppress pneumonia and acute respiratory distress syndrome (ARDS), against SARS-CoV-2. It was expected that fatty acid acylation would greatly enhance cellular internalization and cytosolic distribution of the peptide through the cell membrane. Thus, we synthesized fatty acyl derivative of the N-Ac-Gly4-Ang (1-7) peptide. The peptide was synthesized using Fmoc/tBu solid-phase peptide chemistry and characterized by FT-IR, Zetasizer, and LC-ESI-MS. This study provided more detailed insights into understanding and meeting the basic structural requirements for optimal cellular delivery and formulation of the stearyl Ang (1-7)-peptide conjugate.

Accumulation of Fatty Acylated Fusarium Toxin 2-Amino-14,16-dimethyloctadecan-3-ol, a Class of Novel 1-Deoxysphingolipid Analogues, during Food Storage.

The fusarium toxin 2-amino-14,16-dimethyloctadecan-3-ol (2-AOD-3-ol) is characterized as a sphingolipid analogue that can be isolated from Fusarium avenaceum-infected crops and fruits. In the current study, we discovered a group of novel metabolites of 2-AOD-3-ol from the F. avenaceum-fermented rice culture. 2-AOD-3-ol was predominantly present as a C16:1 fatty acid-assembled ceramide-mimic form rather than as a free base. Although 2-AOD-3-ol and its fatty acyl derivatives were barely detected in fresh samples, the contents of these fusarium toxins accumulated with the extension of storage time up to approximately 32-50 mg/kg dry weight in naturally stored rice, grapes, apples, and oranges. Our finding provides insight into the quality and safety of food during storage through a novel aspect: the C14-C24 fatty acyl 2-AOD-3-ol in nature, which calls for further studies to address their potential impact on human health.

Pharmacosomes: A Versatile Delivery System for Problematic Molecules

Amongst various lipids-based vesicular system, pharmacosomes bear unique advantage over various other lipid based vesicular system. Pharmacosomes are novel vesicular drug delivery system. Pharmacosomes impart better biopharmaceutical properties for synthetic and herbal drugs. Drug incorporated in pharmacosomes encompasses increased bioavailability, reduced toxicity and enhanced stability. Pharmacosome are generally prepared via phospholipid, but various drugs have been derived from different lipid moieties. These include fatty acyl derivatives, fatty alcohol derivative, cholesteryl derivatives. Pharmacosome were evaluated for different parameters such as size, surface morphology, drug entrapment, solubility and in vitro drug release rate. There has been advancement in the scope of this delivery system for several drugs used including NSAIDs, Anti-cancer, anti-viral, anti-hypertension and diuretic drugs. This article reviews the latent pharmacosome as a novel controlled and targeted drug delivery system and highlights the methods of preparation and characterization and application of pharmacosome in drug delivery for herbal and synthetic drugs.

Evolution of the codling moth pheromone via an ancient gene duplication

BackgroundDefining the origin of genetic novelty is central to our understanding of the evolution of novel traits. Diversification among fatty acid desaturase (FAD) genes has played a fundamental role in the introduction of structural variation in fatty acyl derivatives. Because of its central role in generating diversity in insect semiochemicals, the FAD gene family has become a model to study how gene family expansions can contribute to the evolution of lineage-specific innovations. Here we used the codling moth (Cydia pomonella) as a study system to decipher the proximate mechanism underlying the production of the ∆8∆10 signature structure of olethreutine moths. Biosynthesis of the codling moth sex pheromone, (E8,E10)-dodecadienol (codlemone), involves two consecutive desaturation steps, the first of which is unusual in that it generates an E9 unsaturation. The second step is also atypical: it generates a conjugated diene system from the E9 monoene C12 intermediate via 1,4-desaturation.ResultsHere we describe the characterization of the FAD gene acting in codlemone biosynthesis. We identify 27 FAD genes corresponding to the various functional classes identified in insects and Lepidoptera. These genes are distributed across the C. pomonella genome in tandem arrays or isolated genes, indicating that the FAD repertoire consists of both ancient and recent duplications and expansions. Using transcriptomics, we show large divergence in expression domains: some genes appear ubiquitously expressed across tissue and developmental stages; others appear more restricted in their expression pattern. Functional assays using heterologous expression systems reveal that one gene, Cpo_CPRQ, which is prominently and exclusively expressed in the female pheromone gland, encodes an FAD that possesses both E9 and ∆8∆10 desaturation activities. Phylogenetically, Cpo_CPRQ clusters within the Lepidoptera-specific ∆10/∆11 clade of FADs, a classic reservoir of unusual desaturase activities in moths.ConclusionsOur integrative approach shows that the evolution of the signature pheromone structure of olethreutine moths relied on a gene belonging to an ancient gene expansion. Members of other expanded FAD subfamilies do not appear to play a role in chemical communication. This advises for caution when postulating the consequences of lineage-specific expansions based on genomics alone.

Safety Assessment of Tripeptide-1, Hexapeptide-12, Their Metal Salts and Fatty Acyl Derivatives, and Palmitoyl Tetrapeptide-7 as Used in Cosmetics

Tripeptide-1, Hexapeptide-12, their metal salts and fatty acyl derivatives, and Palmitoyl Tetrapeptide-7 function primarily as skin conditioning agents, and Palmitoyl Tripeptide-1, Palmitoyl Hexapeptide-12, Tripeptide-1, Copper Tripeptide-1, and Palmitoyl Tetrapeptide-7 are also used in cosmetic products. Typical use concentrations of these ingredients are <10 ppm. The Panel noted that the low use concentrations and negative safety test data reviewed obviate any concerns relating to the safety of these ingredients in cosmetic products. Thus, the Panel concluded that these ingredients are safe in cosmetics in the present practices of use and concentration described in this safety assessment.

Design, Synthesis, and Evaluation of Homochiral Peptides Containing Arginine and Histidine as Molecular Transporters.

Linear (HR)n and cyclic [HR]n peptides (n = 4,5) containing alternate arginine and histidine residues were synthesized. The peptides showed 0–15% cytotoxicity at 5–100 µM in human ovarian adenocarcinoma (SK-OV-3) cells while they exhibited 0–12% toxicity in human leukemia cancer cell line (CCRF-CEM). Among all peptides, cyclic [HR]4 peptide was able to improve the delivery of a cell impermeable fluorescence-labeled phosphopeptide by two-fold. Fatty acids of different alkyl chain length were attached at the N-terminal of the linear peptide (HR)4 to improve the molecular transporter property. Addition of fatty acyl chains was expected to help with the permeation of the peptides through the cell membrane. Thus, we synthesized seven fatty acyl derivatives of the linear (HR)4 peptide. The peptides were synthesized using Fmoc/tBu solid phase peptide chemistry, purified by reverse-phase high-performance liquid chromatography (RP-HPLC) and characterized by matrix-assisted laser desorption/ionization (MALDI) spectrometry. The fatty acyl peptides containing C8, C12, C14, and C18 alkyl chain did not show cytotoxicity on SK-OV-3 or CCRF-CEM cell lines up to 50 µM concentration; however, at higher concentration (100 µM), they showed mild cytotoxicity. For example, C16-(HR)4 was also found to reduce the proliferation of SK-OV-3 cells by 11% at 50 µM and C20-(HR)4 showed mild toxicity at 10 µM, reducing the proliferation of SK-OV-3 cells by 21%. Increase in the length of alkyl chain showed cytotoxicity to the cell lines. C20-(HR)4 peptide showed better efficiency in translocation of F′-GpYEEI to SK-OV-3 than the phosphopeptide alone. Further investigation of C20-(HR)4 peptide efficacy showed that the peptide could deliver doxorubicin and epirubicin into SK-OV-3 and also improved the drug antiproliferative ability. These studies provided insights into understanding the structural requirements for optimal cellular delivery of the fatty acyl-(HR)4 peptide conjugates.

The influence of juicing on the appearance of blueberry metabolites 2 h after consumption: a metabolite profiling approach.

The consumption of berries has been linked to decreased risk of degenerative disease. Berries are regularly processed into juices. It is largely unknown how the juicing process affects the bioavailability of metabolites. As metabolomics has shown to be a valuable nutritional tool to study global metabolite differences, the aim of this study was to investigate the effect of juicing on the relative appearance of blueberry metabolites in humans using metabolomics. Nine healthy subjects consumed 250 g of fresh blueberries either as the whole fruit or after juicing, and provided blood and urine samples before and 2 h after intake in a cross-over design. Samples underwent metabolite profiling using LCMS, and data were mined with multivariate analysis. Overall, <12 % of all ions detected were significantly influenced by blueberry treatment (P<0·05). Partial least-squared discriminant analysis models of post-treatment samples revealed good discrimination. In urinary samples, whole blueberry treatment resulted in 108 ions that were significantly higher compared with juiced treatment (positive and negative mode combined), whereas only eight were significantly higher after juiced treatment. Examples of putative annotations included metabolites of ferulic and caffeic acids, several phenolic metabolites conjugated to sulphate, glycoside or glucuronide and fatty acyl derivatives, which were of higher intensity after whole blueberry treatment. In conclusion, consumption of whole blueberries resulted in a higher range of phenolic and other metabolites in plasma and urine samples 2 h after consumption. Both whole and juiced blueberries resulted in very similar metabolite profiles at 2 h, although this was the only time point measured.

An ancient remedial repurposing: synthesis of new pinocembrin fatty acid acyl derivatives as potential antimicrobial/anti-inflammatory agents

Five new pinocembrin derivatives (MC1-MC5) were synthesized by Steglich reaction, and investigated for their antimicrobial, antioxidant, and anti-inflammatory activity. MC2 (oleoyl derivative) and MC3 (linoleoyl derivative) have shown the highest inhibitory effects on bacterial proliferation, with MIC values of 32 μg/mL against Staphylococcus aureus. The docosahexaenoyl derivative MC5 displayed the highest anti-inflammatory activity, decreasing NO production in LPS-stimulated macrophages with an IC50 value of 15.51 μg/mL higher than the positive control diclofenac (IC50 of 39.71 μg/mL). All new synthesized compounds showed no anti-proliferative effects on RAW 264.7 cells. Results demonstrated as the introduction of fatty acid substituents improved the biological profile of pinocembrin. Moreover, the chemical nature of substituents significantly affects the bioactivity. These preliminary results outline the importance to investigate the synthesis of pinocembrin fatty acids derivatives as new and safe anti-microbial/anti-inflammatory agents.

Synthesis, characterization, and in vitro cytotoxicity of fatty acyl-CGKRK-chitosan oligosaccharides conjugates for siRNA delivery

In this studies, three fatty acyl derivatives of CGKRK homing peptides were coupled successfully to chitosan oligosaccharides (COS) using sulfosuccinimidyl-4-(N-maleimidomethyl)cyclohexane-1-carboxylate sodium salt (sulfo-SMCC). The COS-SMCC was prepared by direct coupling between COS and sulfo-SMCC in PBS (pH7.5) at RT for 48h. The structure of COS-SMCC and the three fatty acyl-CGKRK-SMCC-COS conjugates were characterized by FT-IR, 13C NMR, and SEM. The ability of three conjugates to condense siRNA into nanosized polyplexes and their efficacy in protecting siRNA from serum nucleases degradation were investigated. Among the investigated derivatives, S-CGKRK-COS showed higher siRNA binding affinity as compared to the P-CGKRK-COS and O-CGKRK-COS, respectively. At a ratio of 10:1, complete protection for siRNA from early enzymatic degradation was achieved. The polymers and the polymer/siRNA polyplexes showed negligible cytotoxicity on human breast cancer cell line MDA-MB-231 at all investigated ratios. However, the polyplexes prepared with palmitoyl and oleoyl derivatives at polymer concentration 10μg/mL reduced the cell viability by 21.5% and 35%, respectively. The results of this study revealed the potential use of fatty acyl-CGKRK-COS as a siRNA carrier and confirmed the importance of incorporating a hydrophobic moiety into chitosan to improve its capacity in complexing with siRNA and protection from degradation.

Multidimensional Liquid Chromatography Coupled with Tandem Mass Spectrometry for Identification of Bioactive Fatty Acyl Derivatives.

Recognition of the contributions of lipids to cellular physiology, both as structural components of the membrane and as modulatory ligands for membrane proteins, has increased in recent years with the development of the biophysical and biochemical tools to examine these effects. Their modulatory roles in ion channels and transporters function have been extensively characterized, with the molecular mechanisms of these activities being the subject of intense scrutiny. The physiological significance of lipids in biochemistry is expanding as numerous fatty acyls are discovered to possess signaling properties. These bioactive lipids are often found in quantities of pmol/g of tissue and are co-extracted with numerous lipophilic molecules, making their detection and identification challenging. Common analytical methodologies involve chromatographic separation and mass spectrometric techniques; however, a single chromatographic step is typically ineffective due to the complexity of the biological samples. It is, therefore, essential to develop approaches that incorporate multiple dimensions of separation. Described in this manuscript are normal phase and reversed phase separation strategies for lipids that include detection of the bioactive primary fatty acid amides and N-acyl glycines via tandem mass spectrometry. Concerted utilization of these approaches are then used to separate and sensitively identify primary fatty acid amides extracted from homogenized tissue, using mouse brains as a test case.

The Identification and Quantification of Suberin Monomers of Root and Tuber Periderm from Potato (Solanum tuberosum) as Fatty Acyl tert-Butyldimethylsilyl Derivatives.

Protective plant lipophilic barriers such as suberin and cutin, with their associated waxes, are complex fatty acyl derived polyesters. Their precise chemical composition is valuable to understand the specific role of each compound to the physiological function of the barrier. To develop a method for the compositional analysis of suberin and associated waxes by gas chromatography (GC) coupled to ion trap-mass spectrometry (IT-MS) using N-(tert-butyldimethylsilyl)-N-methyl-trifluoroacetamide (MTBSTFA) as sylilating reagent, and apply it to compare the suberin of the root and tuber periderm of potato (Solanum tuberosum). Waxes and suberin monomers from root and periderm were extracted subsequently using organic solvents and by methanolysis, and subjected to MTBSTFA derivatisation. GC analyses of periderm extracts were used to optimise the chromatographic method and the compound identification. Quantitative data was obtained using external calibration curves. The method was fully validated and applied for suberin composition analyses of roots and periderm. Wax and suberin compounds were successfully separated and compound identification was based on the specific (M-57) and non-specific ions in mass spectra. The use of calibration curves built with different external standards provided quantitative accurate data and showed that suberin from root contains shorter chained fatty acyl derivatives and a relative predominance of α,ω-alkanedioic acids compared to that of the periderm. We present a method for the analysis of suberin and their associated waxes based on MTBSTFA derivatisation. Moreover, the characteristic root suberin composition may be the adaptive response to its specific regulation of permeability to water and gases. Copyright © 2016 John Wiley & Sons, Ltd.

Ultralong Fatty Acyl Derivatives As Occlusive Structure Lipids for Cosmetic Applications: Synthesis and Characterization

Finding sustainable and commercially viable sources of occlusive materials, as an alternative to petroleum, is of great interest. Inspired by the fundamental role of long chain fatty acids in maintaining skin barrier, ultralong fatty acyl derivatives with diverse structures (varied acyl chain length and different polar head; i.e. glycerol, ethylene glycol, and diethylene glycol) were synthesized. These molecules can be feasibly obtained via enzymatic esterification of fatty acids or fractionated from commercial glycerides mixture via short path distillation. The molecular packing behaviors of compounds were characterized via differential scanning calorimetry, Fourier transform infrared, and Langmuir isotherm measurements. The structure–property relationship study reveals that a glycerol molecule monoacylated with an ultralong fatty acyl is the derivative which entails the most occlusive properties of the series of ultralong chain fatty acid derivatives. Fast Fourier transform filtering (FFTF) analysis of ...

Design, Synthesis, Antiviral Activity, and Pre-Formulation Development of Poly-L-Arginine-Fatty Acyl Derivatives of Nucleoside Reverse Transcriptase Inhibitors

GRAPHICAL ABSTRACT

A Novel Fatty Acyl Desaturase from the Pheromone Glands of Ctenopseustis obliquana and C. herana with Specific Z5-Desaturase Activity on Myristic Acid

Sexual communication in the Lepidoptera typically involves a female-produced sex pheromone that attracts males of the same species. The most common type of moth sex pheromone comprises individual or blends of fatty acyl derivatives that are synthesized by a specific enzymatic pathway in the female’s pheromone gland, often including a desaturation step. This reaction is catalyzed by fatty acyl desaturases that introduce double bonds at specific locations in the fatty acid precursor backbone. The two tortricid moths, Ctenopseustis obliquana and C. herana (brown-headed leafrollers), which are endemic in New Zealand, both use (Z)-5-tetradecenyl acetate as part of their sex pheromone. In C. herana, (Z)-5-tetradecenyl acetate is the sole component of the pheromone. Labeling experiments have revealed that this compound is produced via an unusual Δ5-desaturation of myristic acid. Previously six desaturases were identified from the pheromone glands of Ctenopseustis and its sibling genus Planotortrix, with one differentially regulated to produce the distinct blends used by individual species. However, none were able to conduct the Δ5-desaturation observed in C. herana, and presumably C. obliquana. We have now identified an additional desaturase gene, desat7, expressed in the pheromone glands of both Ctenopseustis species, which is not closely related to any previously described moth pheromone desaturase. The encoded enzyme displays Δ5-desaturase activity on myristic acid when heterologously expressed in yeast, but is not able to desaturate any other fatty acid (C8–C16). We conclude that desat7 represents a new group of desaturases that has evolved a role in the biosynthesis of sex pheromones in moths.Electronic supplementary materialThe online version of this article (doi:10.1007/s10886-013-0373-1) contains supplementary material, which is available to authorized users.

Synthesis of fatty acyl derivatives of 24-epibrassinolide

A number of fatty acid (palmitic, myristic and lauric) esters (both 3α- and 3β-isomers) of epibrassinolide has been prepared as reference compounds for metabolic studies. Selective protection of the three of four hydroxyl groups of epibrassinolide was successively performed first as cyclic 22,23-methylboronates and then as 2α-benzyl ethers. α,β-Inversion of C-3 hydroxyl group was achieved through a consecutive oxidation-reduction reactions or by a nucleophilic substitution of the 3α-mesylates. Treatment of the 3α- and 3β-alcohols with palmitic, myristinic or lauric acid chlorides gave the corresponding esters. The hydrolysis of 22,23-methylboronates was performed after their transformation into 2-hydroxy-1,3,2-dioxaborolanes using a cation exchange column with DOWEX 50WX8 in NH4+ form. Hydrogenolysis of the benzyl ethers catalyzed by palladium yielded the target compounds.This article is part of a Special Issue entitled “Synthesis and biological testing of steroid derivatives as inhibitors”.

Medium‐chain alkyl esters of tyrosol and hydroxytyrosol antioxidants by cuphea oil transesterification

AbstractEffective lipophilic antioxidants were prepared by non‐aqueous enzymatic transesterification of plant phenols with cuphea oil. Tyrosol and hydroxytyrosol, abundantly available phenols from olive oil processing byproduct, were found to be predominately acylated with capric acid derived from the triglyceride fraction of the Cuphea germplasm line PSR 23 (Cuphea Viscosissima × C. lanceolata). The reaction was complete within 2 h, with a &gt;97% conversion of either phenol using immobilized Candida antarctica lipase B. The reaction products were good solvents for tyrosol or hydroxytyrosol, suggesting a facile manufacturing route not dependent on use of organic solvents. Phenolic derivatives were assessed for their ability to serve as antioxidants for preventing the oxidation of polyunsaturated fatty acyl groups. The antioxidant capacities of the cuphea‐derived fatty acyl derivatives of tyrosol or hydroxytyrosol were the same as their respective derivatives prepared from decanoic acid. These biobased antioxidants may improve the oxidative stability of sensitive fatty acids in food applications.Practical applications: A new biobased antioxidant was created for the food industry. Foods can contain fats and oils that are susceptible to deterioration during storage, which can limit product quality and shelf‐life. Synthetic antioxidants can slow the spoilage process, although there are limitations to how much can be added to foods. The food industry is interested in using natural ingredients to solve storage stability problems. We found that the oil from the plant Cuphea, cultivated in the upper Midwest region of the US, is very useful for modifying olive oil waste molecules to create antioxidants for use in foods. The developed process would be suitable for commercial production. This research creates a new commercial use for a specialty oil seed crop, expands the market for cuphea oil, and has developed two novel antioxidants to help the food industry improve food quality.

Synthesis and Biological Evaluation of Fatty Acyl Ester Derivatives of (−)-2′,3′-Dideoxy-3′-thiacytidine

A number of fatty acyl derivatives of (-)-2',3'-dideoxy-3'-thiacytidine (lamivudine, 3TC, 1) were synthesized and evaluated for their anti-HIV activity. The monosubstituted 5'-O-fatty acyl derivatives of 3TC (EC(50) = 0.2-2.3 μM) were more potent than the corresponding monosubstituted N(4)-fatty acyl (EC(50) = 0.4-29.4 μM) and 5'-O-N(4)-disubstituted (EC(50) = 72.6 to >154.0 μM) derivatives of the nucleoside. 5'-O-Myristoyl (16) and 5'-O-12-azidododecanoyl derivatives (17) were found to be the most potent compounds (EC(50) = 0.2-0.9 μM) exhibiting at least 16-36-fold higher anti-HIV activity against cell-free virus than 1 (EC(50) = 11.4-32.7 μM). The EC(90) values for 16 against B-subtype and C-subtype clinical isolates were several folds lower than those of 1. The cellular uptake studies confirmed that compound 16 accumulated intracellularly after 1 h of incubation with CCRF-CEM cells and underwent intracellular hydrolysis. 5'-O-Fatty acyl derivatives of 1 showed significantly higher anti-HIV activity than the corresponding physical mixtures against the B-subtype virus.

Synthesis and evaluation of fatty acyl ester derivatives of cytarabine as anti-leukemia agents

Cytarabine is a chemotherapeutic agent predominately used for the treatment of acute myeloid leukemia and lymphoblastic leukemia. Cytarabine is a polar nucleoside, has a short plasma half-life, and its use is associated with severe side effects. Fatty acyl derivatives of cytarabine were synthesized with the expectation to improve cellular uptake and generate derivatives with a longer duration of action. Multi-step protection and deprotection reactions of hydroxyl and amino groups and conjugation with a fatty acid (i.e., myristic acid and 12-thioethyldodecanoic acid) afforded 5′- O-substituted, 2′- O-substituted, and 2′,5′-disubstituted fatty acyl derivatives of cytarabine. 2′,5′-Dimyristoyl derivative of cytarabine was found to inhibit the growth of CCRF-CEM cells by approximately 76% at concentration of 1 μM after 96 h incubation.

Chemoenzymatic Synthesis of a Glycolipid Library and Elucidation of the Antigenic Epitope for Construction of a Vaccine Against Lyme Disease

Lyme disease (LD) is the most common tick-borne disease in Europe, North America, and Asia. The etiologic agents of LD are spirochetes of the group Borrelia burgdorferi sensu lato, which possess a lipid content of 25-30% of the dry weight. The major glycolipid cholesteryl 6-O-acyl-beta-D-galactopyranoside (ACGal), present in B. burgdorferi sensu stricto, B. afzelii, and B. garinii, is a specific and highly prevalent antigen frequently recognized by antibodies in late-stage LD. Here we report a convenient route for the chemical synthesis of ACGal by employing a combination of chemical synthesis steps with enzymatic transformations. This synthesized molecule was compared with bacterial extracts by immunoblots with patient sera, confirming the preserved antigenicity. Next, a glycolipid library derived from the native molecules with variations in the fatty acyl moiety and derivatives in which the cholesterol has been replaced was designed and synthesized. The chemical structures were confirmed by 1D and 2D NMR spectroscopy and mass spectrometry. The native and synthetic glycolipids were utilized in immunoblots to determine the epitope recognized by antibodies in patient sera. By this method we could demonstrate that galactose, cholesterol, and a fatty acid with a minimal chain length of four carbon atoms comprises the essential structure for recognition by antibodies. Finally, this finding allowed the synthesis of a functionalized ACGal with an omega-mercapto group at the fatty acid and a facile protection and deprotection strategy. This antigenic hapten can be conjugated to a carrier protein to effect immunization against Lyme disease.