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PubMed1998

Phospholipase A2 relieves phosphatidylcholine inhibition of micellar cholesterol absorption and transport by human intestinal cell line Caco-2.

Cholesterol absorption from bile acid micelles is suppressed by phosphatidylcholine (PC) in the micelles. The effects of micellar phospholipid composition on absorption, metabolism, and secretion of lipids were examined in Caco-2 cells incubated with micelles composed of taurocholic acid, cholesterol, oleic acid, monooleoylglycerol, and phospholipid. Significant amounts of all micelle lipids were absorbed from micelles lacking phospholipid. Cholesterol absorption was accompanied by cholesterol esterification and secretion. Micellar oleic acid was also absorbed and reesterified primarily into triacylglycerol which was also secreted. Lipid absorption and secretion from micelles containing lysophosphatidylcholine (LPC) were similar to that obtained with phospholipid-free micelles. LPC was also extensively absorbed. In contrast, incubations with PC-containing micelles resulted in large reductions in the absorption, esterification, and secretion of cholesterol without significant decreases in oleic acid absorption, conversion to acylated lipids, or triacylglycerol secretion. A relatively small reduction in monoacylglycerol absorption from PC-containing micelles was detected. Retinol absorption was not affected by micellar PC. Substitution of LPC for half or more of the PC reversed the PC-dependent decrease in cholesterol absorption. Pancreatic phospholipase A2 (pPLA2) enhanced cholesterol absorption from PC-containing micelles. The pPLA2-dependent increase in cholesterol absorption was inhibited by the pPLA2 inhibitor FPL 67047XX. The results indicate micellized cholesterol absorption by enterocytes is uniquely dependent on the elimination of micellar phosphatidylcholine and thus directly dependent on the lipolytic action of pancreatic phospholipase A2 (pPLA2). Consequently, pPLA2 inhibitors may be a new and novel class of cholesterol absorption inhibitors for therapeutic use.

Benzhydryl Compounds↗
PubMedDate not supplied

Evidence for the possible involvement of protein kinase C in the activation of non-specific phospholipase A2 in human neutrophils.

In this article, we provide mass data on released fatty acids in neutrophils stimulated with A23187 in the presence and absence of phorbol 12-myristate 13-acetate (PMA). A23187 alone caused a highly selective accumulation of non-esterified arachidonic acid (AA) relative to other saturated (palmitic and stearic acids) and unsaturated fatty acids (oleic and linoleic acids). However, the absolute levels of non-esterified arachidonic acid, oleic acid and linoleic acid were significantly increased (by twofold) in response to the action of A23187 in the presence of PMA. We also noted a further twofold increase in the non-esterified arachidonic acid in the presence of BW755C, a dual inhibitor of cyclooxygenase and lipoxygenases, with no apparent change in the levels of oleic and linoleic acids and other saturated fatty acids. These results suggest that PMA potentiates not only the release of AA but also the release of oleic and linoleic acids from neutrophil phosphoglycerides. This is possibly due to the activation of non-specific phospholipase A2 (PLA2). Our data also suggest a possible role for the 5-lipoxygenase metabolites in PMA-induced synergism with regard to the release of AA through AA-specific and PMA-sensitive PLA2. Protein kinase C appears, therefore, to play a role in the regulation of both AA-specific and non-specific PLA2 in human neutrophils.

Arachidonic Acid↗
PubMed1991

Chemical communication of emigration behavior of Drosophila melanogaster. II. Identification of chemical substances.

Two chemical substances isolated from adult flies of Drosophila melanogaster differently affected the emigration activity of genetically different strains. These substances were identified as palmitic acid and oleic acid, respectively. Chemical and biological comparisons of the natural and authentic compounds showed them to be identical. The behavior response was dependent on the concentration of these fatty acids. The two chemical substances are excreted by adult flies, both male and female, but the emigration activity of one strain was affected by only palmitic acid and that of the other strain, by only oleic acid.

Animals↗
PubMed1998

Mixture experiments with the oil phase of parenteral emulsions.

The effects of the oil phase as a mixture (binary, ternary) on the emulsion droplet size were investigated. The binary trials were performed with the aid of simplex lattice design with constraints. Droplet diameter was evaluated in terms of the oil phase viscosity and the interfacial tension between oil phase and the aqueous phase. As a result it could be shown that increasing the oil phase viscosity as a function of castor oil concentration led to a greater increase in particle size. At the same time, decreasing the interfacial tension of the oil phase as a function of oleic acid or oleic alcohol was shown to have a negligible effect on the particle size of the dispersed phase. A further aim was to find out a formulation by using a ternary oil phase resulting in a stable emulsion which could pass the autoclaving process. It was ascertained that oleic acid as a part of the oil phase led to proper formulation showing a satisfactory stability.

Castor Oil↗
PubMed1969

Studies on the positional integrity of glyceride fatty acids during digestion and absorption in rats.

1. Rats previously starved for 24hr. were separately given by intraduodenal injections 0.5ml. of a dispersion containing 10mg. of sodium taurocholate, with 50mg. of glycerol 1,3-dioleate 2[1-(14)C]-palmitate, glycerol 1,2-dioleate 3[1-(14)C]-palmitate, a mixture of [1-(14)C]palmitic acid and triolein, or a mixture of [1-(14)C]-palmitic acid and oleic acid. 2. At the end of 30min., the net amounts, and the radioactivity, of the neutral-lipid components recovered from the intestinal lumen and mucosa, and the position of the labelled palmitic acid in the mucosal triglycerides, were determined. 3. When glycerol 1,3-dioleate 2[1-(14)C]-palmitate was administered, most of the labelled acid was retained in the di- and monoglycerides of the lumen; the triglycerides were the major components containing the radioactivity in the mucosa and 75-80% of the labelled acid was located at the beta-position of these triglycerides. 4. When glycerol 1,2-dioleate 3[1-(14)C]-palmitate was administered, the labelled acid was readily split off in the lumen and virtually no radioactivity could be traced in the monoglyceride fraction; in the intestinal mucosa, triglycerides were again the chief components containing most of the radioactivity, and 80-85% of the labelled acid was esterified at the outer positions of the glycerol. 5. When [1-(14)C]palmitic acid mixed with triolein was administered, the concentrations of free fatty acids increased markedly in the intestinal lumen and mucosa, and 80-88% of the radioactivity of the mucosal triglycerides was located at the outer positions of the glycerol. 6. When [1-(14)C]palmitic acid mixed with oleic acid was administered, the labelled acid accumulated in the lumen as well as in the cell, and it was randomly incorporated into all three positions of the mucosal triglycerides.

Animals↗
PubMed2002

(13)C NMR characterization of triacylglycerols of Moringa oleifera seed oil: an "oleic-vaccenic acid" oil.

The composition of acyl chains and their positions in the triacylglycerols of the oil extracted from seeds of Moringa oleifera were studied by (13)C NMR spectroscopy. The unsaturated chains of M. oleifera seed oil were found to comprise only mono-unsaturated fatty acids and, in particular, two omega-9 mono-unsaturated acids, (cis-9-octadecenoic (oleic acid) and cis-11-eicosenoic acids) and one omega-7 mono-unsaturated acid (cis-11-octadecenoic acid (vaccenic acid)). The mono-unsaturated fatty acids were detected as separated resonances in the spectral regions where the carbonyl and olefinic carbons resonate according to the 1,3- and 2-positions on the glycerol backbone. The unambiguous detection of vaccenic acid was also achieved through the resonance of the omega-3 carbon. The (13)C NMR methodology enabled the simultaneous detection of oleate, vaccenate, and eicosenoate chains according to their positions on the glycerol backbone (1,3- and 2-positions) through the carboxyl, olefinic, and methylene envelope carbons of the triacylglycerol acyl chains.

Carbon Isotopes↗
PubMed2002

Endothelin ET(B) receptor-mediated mechanisms involved in oleic acid-induced acute lung injury in mice.

The receptors underlying the endothelin-dependent component of lung plasma extravasation and leucocyte infiltration induced by oleic acid were assessed in mice. Oleic acid (1 mg.kg(-1) intravenously), but not endothelin-1 (up to 1 nmol.kg(-1) intravenously), increased accumulation of Evans blue in the lungs (excluding the trachea and main bronchi) from 11.8+/-3.9 to 98.6+/-10.7 microg 1 h after injection. Bosentan, the antagonist of endothelin receptors (ET(A) and ET(B)) or the selective ET(B) receptor antagonists Ro 46-8443 or A-192621 (administered 1 h before oleic acid at doses of 30, 10 and 30 mg x kg(-1) respectively) reduced the effect of oleic acid by 71%, 58% and 79% respectively. However, the selective ET(A) receptor antagonist A-127722.5 (10 mg x kg(-1)) was inactive. Oleic acid (2 mg xkg(-1), intravenously) raised the number of total leucocytes, mononuclear cells and neutrophils in broncho-alveolar lavage fluid 4 h after injection. Bosentan and Ro 46-8443 (at doses of 30 and 10 mg x kg(-1) respectively) inhibited the neutrophil infiltration induced by oleic acid by approx. 80%. None of the antagonists modified control (basal) pulmonary microvascular permeability or total and differential cell counts. Thus, endogenous endothelins, acting via ET(B) receptor-dependent mechanisms, play a major role in oleic acid-induced lung injury in the mouse by promoting infiltration of circulating neutrophils and enhancement of pulmonary microvascular plasma extravasation. These findings suggest that either ET(B) or mixed ET(A)/ET(B) receptor antagonists might be beneficial in the treatment of the adult respiratory distress syndrome.

Acute Disease↗
PubMed1991

Mechanism of oleic acid-induced inhibition on gastric acid secretion in rats.

We investigated the existence of an enterogastrone in rats induced by duodenal administration of oleic acid. Acid secretion by the luminally perfused stomach was stimulated in anesthetized rats by intravenous infusion of 0.3 micrograms.kg-1.h-1 pentagastrin. Intraduodenal administration of 3 mmol of oleic acid produced a profound inhibition (94%) of pentagastrin-stimulated acid output in 10 rats (P less than 0.01). Of several peptides in plasma including secretin, neurotensin, somatostatin, and peptide YY, only secretin was found to increase significantly (P less than 0.001). A similar degree of inhibition of acid output (93%) was caused by porcine secretin, 5.6 pmol.kg-1.h-1, given intravenously to mimic the plasma level of secretin produced by oleic acid infusion. The inhibitory effect of oleic acid on the acid secretion was completely reversed by intravenous injection of a rabbit antisecretin serum but not by a normal rabbit serum. These observations strongly suggest that the inhibition was mediated via circulating secretin. The inhibition produced by either oleic acid or secretin was completely blocked by indomethacin. The blocking action was completely reversed by intravenous administration of 48 micrograms.kg-1.h-1 prostaglandin E2. We conclude that endogenous secretin is a major enterogastrone released by oleic acid in anesthetized rats and that the inhibitory action of secretin requires endogenous prostaglandins.

Animals↗
PubMed1990

Insulin receptor tyrosine kinase-catalyzed phosphorylation of 422(aP2) protein. Substrate activation by long-chain fatty acid.

It was established previously that the 15-kDa protein phosphorylated in 3T3-L1 adipocytes treated with insulin and phenylarsine oxide is O-phospho-Tyr19 422(aP2) protein, a fatty acid-binding protein. To assess its capacity to serve as substrate of the insulin receptor tyrosine kinase in vitro, native 422(aP2) protein was isolated from 3T3-L1 adipocytes and purified to homogeneity. Receptor-catalyzed phosphorylation of 422(aP2) protein on Tyr19 was markedly activated when long-chain fatty acid, e.g. oleic acid, is bound to the protein. Fatty acid had no effect on autophosphorylation of the insulin receptor by its intrinsic tyrosine kinase. Both saturated (C14, C16, and C18) and unsaturated (all cis-delta 9 C16, -delta 9 C18, and -delta 9,12 C18, -delta 9,12,15 C18, and -delta 5,8,11,14 C20) fatty acids caused substrate activation. The Km for 422(aP2) protein was greatly reduced (from 170 to 3 microM) by oleic acid with little or no effect on Vmax. Upon binding fatty acid to 422(aP2) protein the susceptibility of Tyr19 and Tyr128 to iodination by the lactoperoxidase method increased greatly. These results indicate that upon binding fatty acid, 422(aP2) protein undergoes a conformational change whereby Tyr19, which lies within a consensus-type sequence for tyrosine kinase substrates, becomes accessible for phosphorylation by the insulin receptor tyrosine kinase and to iodination by lactoperoxidase.

Adipose Tissue↗
PubMedDate not supplied

Preparation of conjugates of oligodeoxynucleotides and lipid structures and their interaction with low-density lipoprotein.

The high expression level of receptors for low-density lipoprotein (LDL) on tumor cells makes LDL an attractive carrier for selective delivery of drugs to these cells. The aim of this study is to allow incorporation of oncogene-directed antisense oligodeoxynucleotides (ODNs) into the lipid moiety of LDL. Therefore, ODNs were conjugated with oleic acid, cholesterol, and several other steroid lipids. These latter steroid lipids were synthesized starting from bile acids and were varied in lipophilicity by attaching oleic acid ester structures. The lipid structures, activated as pentafluorophenyl esters, were conjugated in solution phase to 3'-amino-tailed ODNs. The ODNs conjugated with lithocholic acid, oleic acid, and cholesterol could easily be purified by reversed phase (RP)-HPLC. However, the ODNs conjugated with the oleoyl steroid ester structures irreversibly bound to the column material. These highly lipidic ODNs were separated from the nonconjugated ODN by electrophoresis in a 1% low-melting agarose gel containing 0.1% Tween 20. This method was found to be very effective in isolating the ODNs conjugated to the oleoyl steroid ester structures. The ODNs conjugated with cholesterol and the oleoyl esters of lithocholic and cholenic acid associated readily and nearly completely with LDL. However, the less lipidic ODNs and the ODN conjugated with the dioleoyl ester of chenodeoxycholic acid did not and did incompletely associate, respectively. Lithocholic acid and oleic acid are probably not sufficiently lipophilic to induce association with LDL, whereas the dioleoyl ester structure is probably too bulky and extended to allow partitioning into the lipid moiety of LDL. We conclude that several of the lipid-ODNs can associate readily with LDL, enabling delivery of oncogene-directed antisense ODNs via the LDL receptor pathway.

Bile Acids and Salts↗
PubMed1987

Stearic acid and carcinogenesis.

Decreased membrane rigidity is one of the characteristics of malignant cells, resulting in part from the desaturation of stearic acid into oleic acid. In this study we investigated the influence of stearic acid on tumour cell inhibition in vitro and tumour development in vivo. Stearic acid inhibited the colony-forming ability of 4 out of 5 rat and two human tumour continuous cell lines in vitro. In contrast, the colony-forming ability of rat fibroblasts was not inhibited and that of human foetal lung fibroblasts was inhibited at a higher dose than that required to inhibit human tumour cell lines. Using a model of rat mammary carcinoma induced by nitroso-methyl urea (NMU) the subcutaneous injection of stearic acid at weekly intervals prevented tumour development in 5 to 10 rats. Using iodostearic acid twice weekly, 11 of 19 rats were alive and tumour free at week 22 whilst all of 14 animals injected with NMU alone had died of tumour by the 16th week. The ratio of stearic to oleic acids in erythrocyte membranes was significantly reduced in the tumour-bearing rats, but was normal in tumour-free animals treated with stearic or iodostearic acid. These preliminary data indicate that stearic acid inhibits tumour development in rats.

Animals↗
PubMed1999

Inhibition of neurofibromin and p120 GTPase activating protein (GAP) by dietary fatty acids.

Neurofibromin and p120 GTPase activating protein (p120 GAP) down-regulate the activity of cellular Ras proteins. How the activity of these two proteins is controlled is not yet clear. In this study, we analyzed the effects of eight nutritionally relevant fatty acids on GTPase stimulatory activity of full-length neurofibromin and p120 GAP. The fatty acids tested were: saturated stearic acid, monounsaturated oleic acid, three omega-6 and three omega-3 polyunsaturated fatty acids. The analysis was performed by Ras immunoprecipitation GTPase assay. The full-length p120 GAP expressed in insect Sf9 cells and the immunoaffinity purified full-length neurofibromin were used. Neurofibromin was readily inhibited by stearic and oleic acid, but p120 GAP was not inhibited even at high concentrations (> 80 microM). Neurofibromin was also inhibited by low concentrations of all the polyunsaturated fatty acids tested (IC50 of 6 to 16 microM). p120 GAP was 2-3 fold less sensitive to inhibition by these fatty acids. The GTPase stimulatory activity of neurofibromin was also inhibited by arachidonic and oleic acid in the presence of a lipid mixture representing the major lipid components of the cell membrane. Chimeric proteins of neurofibromin and p120 GAP were used to determine that differential sensitivity to fatty acid inhibition maps to the catalytic domain of the proteins. These results indicated that fatty acids can modulate the GTPase function of the c-Ha-Ras protein by inhibiting the GTPase stimulatory activity of two Ras regulators, full-length neurofibromin and p120 GAP, at physiologically relevant concentrations in vitro.

Animals↗
PubMed2000

Mixed endothelin ET(A) and ET(B) antagonist bosentan inhibits oleic acid-induced lung plasma extravasation in mouse.

The possible participation of endogenous endothelins (ETs) in enhancement of plasma extravasation induced by oleic acid was assessed in mice. Oleic acid (0.5-2%/kg, i.v.) increased accumulation of Evans blue in lungs in dose-dependent fashion, with a clearcut peak at 1 h (lung Evans blue content: control 0.17 +/- 0.01; oleic acid 1%/kg 0.63 +/- 0.04 microg per 10 mg wet tissue). Pretreatment with the mixed endothelin-ET(A) and ET(B) (ET(A)/ET(B)) receptor antagonist bosentan (30 mg/kg, i.v., 30 min before oleic acid) markedly reduced lung Evans blue content (to 0.24 +/- 0.04), as did pretreatments with prazosin (1 mg/kg), meloxicam (5 mg/kg) and dexamethasone (1 mg/kg/day, for 3 days). Thus, ETs play a pivotal role in the increase in lung microvascular permeability caused by oleic acid in the mouse. The ET receptors involved in the pulmonary vascular changes associated with this experimental model of adult respiratory distress syndrome (ARDS), as well as the relationship between ETs and the sympathetic system, eicosanoids and cytokines remain to be clarified.

Animals↗
PubMed2026

Integrated phytochemical and bioactivity profiling of Xanthium strumarium fruits from Korea and China: Implications for origin-specific quality specification.

BACKGROUND: Geographic origin influences the phytochemical composition and biological activities of medicinal plant resources. Xanthium strumarium L. (XS) fruit is widely used in East Asian traditional medicine. However, current pharmacopeial standards primarily recognize Chinese-derived material, despite the availability and traditional use of XS in Korea. To address this gap and support origin-informed quality specification, we compared fruits from Korea (XS-K) and China (XS-C) using chloroplast genome sequencing, targeted phytochemical profiling (high-performance liquid chromatography (HPLC) for selected phenolics and gas chromatography-flame ionization detection (GC-FID) for fatty acids and phytosterols, and multivariate chemometric analysis. RESULTS: Chloroplast genome analysis revealed high overall similarity but localized divergence around the rpoC2 locus and a greater mutation burden in XS-C, supporting origin-associated genomic differentiation. Phytochemical profiling revealed distinct origin-dependent metabolic signatures. XS-K showed higher levels of phytosterols, chlorogenic acid, 4,5-dicaffeoylquinic acid (4,5-DCQ), and xanthatin was detected only in XS-K, whereas XS-C exhibited greater abundance of total fatty acids, particularly oleic acid. Unsupervised clustering and log2 fold-change ranking confirmed clear compositional separation, and variable importance in projection (VIP) analysis identified chlorogenic acid, β-sitosterol, oleic acid, 4,5-DCQ, and xanthatin as major discriminators between origins. Bioactivity assays demonstrated that XS-K exerted stronger antioxidant effects in ABTS, DPPH and FRAP assays, stronger skin-related enzyme inhibition, and greater antibacterial activity against Staphylococcus aureus, consistent with its enriched phenolic and sterol profile. CONCLUSION: Together, chloroplast sequence variation, targeted metabolite quantification, and screening bioassays consistently distinguished XS-K from XS-C. These findings support the use of candidate markers for the origin-based authentication and quality control of XS fruit-derived ingredients. © 2026 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Fruit↗
PubMed1994

Cell swelling activates separate taurine and chloride channels in Ehrlich mouse ascites tumor cells.

The taurine efflux from Ehrlich ascites tumor cells is stimulated by hypotonic cell swelling. The swelling-activated taurine efflux is unaffected by substitution of gluconate for extracellular Cl- but inhibited by addition of MK196 (anion channel blocker) and 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS; anion channel and anion exchange blocker) and by depolarization of the cell membrane. This is taken to indicate that taurine does not leave the osmotically swollen Ehrlich cells in exchange for extracellular Cl-, i.e., via the anion exchanger but via a MK196- and DIDS-sensitive channel that is potential dependent. An additional stimulation of the swelling-activated taurine efflux is seen after addition of arachidonic acid and oleic acid. Cell swelling also activates a "Mini Cl- channel." The Cl- efflux via this Cl- channel, in contrast to the swelling-activated taurine efflux, is unaffected by DIDS and inhibited by arachidonic acid and oleic acid. It is suggested that the swelling-activated "Mini Cl- channel" and the swelling-activated taurine channel in the Ehrlich cell represent two distinct types of channels.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1977

Increased incorporation of fatty acids into phospholipids of lungs and livers of rabbits under the influence of bromhexine and ambroxol.

The incorporation of lauric acid, palmitic acid and oleic acid into phospholipids of lung and liver has been studied in tissue slices of control rabbits and of rabbits treated with bromhexine or ambroxol in doses of 10 mg/kg. A marked increase (up to 200% of the controls) of palmitic acid incorporation into phosphatidylcholine (lecithin) and phosphatidylethanolamine of the lung was found whereas the incorporation rate of palmitic acid into lecithin and phosphatidylethanolamine of the liver displayed no significant change. The incorporation of lauric acid and oleic acid into lung phospholipids was not accelerated. The observed effects were more marked in short time experiments (analysis 2 h after drug injection) than after treatements for 7 days. It is concluded that the phospholipid synthesis is stimulated by the drugs especially in the lungs. This seems to be of particular interest with respect to the surfactant system of the lung and might have some therapeutic relevance.

Ambroxol↗
PubMed2004

Use of an 8(1)3(2) asymmetrical factorial design for the in vitro evaluation of ondansetron permeation through human epidermis.

The in vitro permeation of ondansetron through human cadaver epidermis, as a preliminary step toward the development of a transdermal therapeutic system, was investigated. In vitro release studies were carried out using modified Franz diffusion cells and human epidermis, taken from cadaver skin by heat separation technique. To estimate the effect of the type and concentration of the penetration enhancers and the skin from different donors, an 8(1)3(2) asymmetrical factorial design was used. Formulations containing lauric acid and oleic acid as penetration enhancers, showed the largest Q values [amounts of ondansetron permeated per unit area of epidermal membrane (microg/cm2)] at 24, 48, and 72 hr, as well as steady-state flux values, among all formulations tested. The other enhancers increased the flux in the following order: lauryl alcohol>glycerol monooleate>Azone >cineole>oleyl alcohol>1-methyl-2-pyrrolidinone. Moreover, the concentration of the penetration enhancer and the type of the skin were proved to significantly affect the permeation rate of ondansetron through human epidermis. From the results obtained, it was shown that the formulations containing lauric acid or oleic acid at 5% or 10% could increase sufficiently the permeation of ondansetron. Therefore, the transdermal administration of ondansetron seems feasible.

Diffusion Chambers, Culture↗
PubMed1982

Effects of free fatty acids on synaptosomal amino acid uptake systems.

The Na+-dependent synaptosomal uptakes of proline, aspartic acid, glutamic acid, and gamma-aminobutyric acid were strong inhibited by monounsaturated fatty acids. With oleic acid, half-maximal inhibition was observed at about 15 microM. The Na+-independent uptakes of leucine, phenylalanine, histidine, and valine were less sensitive to inhibition by the unsaturated fatty acids. In contrast, the uptakes of all of these amino acids were unaffected by saturated fatty acids. The inhibition of proline uptake (and that of the other Na+-dependent amino acids) by oleic acid was overcome by the addition of serum albumin and the data presented further indicate that the previously reported stimulation of proline uptake by albumin could be related to its fatty acid binding properties.

Amino Acids↗