Study of reaction parameters and kinetics of esterification of lauric acid with butanol by immobilized Candida antarctica lipase.

Esterification of lauric acid with n-butanol, catalyzed by immobilized Candida antarctica lipase (CAL) in aqueous-organic biphasic solvent system was studied. Effects of various reaction parameters on esterification were investigated, such as type and amount of solvent, amount of buffer, pH, temperature, speed of agitation, amount of enzyme, butanol and lauric acid. The most suitable reaction conditions for esterification were observed at 50ºC and pH 7.0 using 5000 μmoles of lauric acid, 7000 μmoles of butanol, 0.25 ml phosphate buffer, 1 ml of isooctane as the solvent and 50 mg of immobilized enzyme in the reaction medium at agitation speed of 150 rpm. Maximum esterification of 96.36% was acheived in 600 min of reaction time at n-butanol to lauric acid molar ratio of 1: 0.7. Kinetic study for the esterification of lauric acid with n-butanol using immobilized CAL was carried out and the kinetic constants were estimated by using non-linear regression method. The estimated value of Michaelis kinetic constants for butanol (KmBt) and acid (KmAc) were 451.56 (M) and 4.7 × 10-7(M), respectively and the value of dissociation constant (KBt) of the butanol-lipase complex was 9.41 × 107(M). The estimated constants agreed fairly well with literature data.

Modificaciones de las lipoproteínas del plasma en voluntarios sometidos a dietas preparadas con aceite de girasol solo o mezclado con oleína de palma / Changes in the content of plasma lipoproteins in persons subjected to diets prepared with sunflower oil alone or mixed with palm olein

En 31 comensales regulares del Comedor Universitario de la Universidad Central de Venezuela (CUUCV), en Caracas. Se observó el efecto de la sustitución del aceite de girasol que se utiliza corrientemente en la preparación de las comidas en ese comedor, por un aceite obtenido de la mezcla de aceite de girasol y oleína de palma, en la proporción 70/30 (v/v) respectivamente. Después de 40 días continuos de la sustitución no hubo cambios significativos en las concentraciones de colesterol total (CT), ni del colesterol de las lipoproteínas de baja densidad (LDL) y muy baja densidad (VLDL). La concentración del colesterol de las lipoproteínas de alta densidad (HDL) aumentó significativamente (p<0,05). Los triglicéridos (TG) del plasma aumentaron en un 30%. La resistencia a la oxidación de las LDL aumentó considerablemente (p< 0,01). Hoy se considera a esta resistencia como un factor protector de gran importancia en la prevención del inicio del proceso aterogénico. Tomando en cuenta las modificaciones favorables como el aumento de colesterol de HDL sin modificación de la LDL y el claro aumento de la resistencia a la oxidación de la LDL, se considera que la oleína de palma es un aceite vegetal que puede ser utilizado sin mayores riesgos en mezcla con otros aceites que tengan una relación linoleico/palmítico más elevada como los aceites de girasol, maíz, soja y otros.

We analyzed in 31 subjects, regular guests of the University food service of the Central University of Venezuela (UCVFS), in Caracas, the effects of replacing sunflower oil, commonly used in the preparation of meals, by a mix of sunflower oil and palm olein 70/30 (v/v) respectively. Plasma concentrations of total cholesterol, low and very low density lipoproteins were not changed after 40 days of the substitution. On the contrary, concentrations of high density lipoprotein and total triglycerides increased. The resistance to the oxidation of low-density lipoproteins increased considerably (p<0, 01). Today this resistance is considered as a protective factor of great importance in the prevention of the initiation of the atherogenic process. Taking into account the favorable modifications of HDL cholesterol and the clear increased resistance to the oxidation of LDL, we think that palm olein, mixed with other oils with a high ratio linoleic/palmític (sunflower, corn, soya an the likes), can be used as a healthy alternative in human nutrition.

Therapeutic effect of lauric acid, a medium chain saturated fatty acid on giardia lamblia in experimentally infected hamsters

Giardia lamblia is a common cause of diarrheal disease in humans, particularly among children causing nutritional disorders. Metronidazole and other nitroimidazoles are commonly used as the mainstay of therapy for giardiasis. The present work was carried out to evaluate the effect of lauric acid, a natural product extracted from coconut oil, against G. lamblia in experimentally infected hamsters [Mesocricetus auratus]. Sixty five laboratory bred hamsters were used in the current experimental study. Ten served as normal non infected non treated control group [A]. Fifteen uninfected hamsters served as drug control group [B]: five received metronidazole group [B1]; five received lauric acid group [B2] and five received combined treatment [metronidazole and lauric acid] at a half doses of each drug [B3]. The remaining forty hamsters were orally infected by 10,000 G. lamblia cysts/hamster [group C], and were divided into 4 groups of 10 hamsters each: infected control [C1]; metronidazole treated [C2]; lauric acid treated [C3]; combined treatment at a half dose of each drug [C4]. Two weeks after treatment, compared with infected non treated controls, the highest percentages of reduction in the number of Giardia cysts and trophozoites were in the group that received combined treatment [98.83%, 96.95%, respectively]. Lower percentages of reduction were recorded for the metronidazole treated group [93.77%, 95.50%, respectively] and the lauric acid treated group [82.03%, 78.76%, respectively]. Histopathological examination and electron microscopic examination revealed complete healing of intestinal mucosa after the combined treatment, while partial healing of the lining epithelium of the intestine was noticed after metronidazole or lauric acid treatment alone. Lauric acid improved the therapeutic effect against giardiasis when combined with metronidazole

Chain length-dependent cooperativity in fatty acid binding and oxidation by cytochrome P450BM3 (CYP102A1)

Fatty acid binding and oxidation kinetics for wild type P450(BM3) (CYP102A1) from Bacillus megaterium have been found to display chain length-dependent homotropic behavior. Laurate and 13-methyl-myristate display Michaelis-Menten behavior while there are slight deviations with myristate at low ionic strengths. Palmitate shows Michaelis-Menten kinetics and hyperbolic binding behavior in 100 mmol/L phosphate, pH 7.4, but sigmoidal kinetics (with an apparent intercept) in low ionic strength buffers and at physiological phosphate concentrations. In low ionic strength buffers both the heme domain and the full-length enzyme show complex palmitate binding behavior that indicates a minimum of four fatty acid binding sites, with high cooperativity for the binding of the fourth palmitate molecule, and the full-length enzyme showing tighter palmitate binding than the heme domain. The first flavin-to-heme electron transfer is faster for laurate, myristate and palmitate in 100 mmol/L phosphate than in 50 mmol/L Tris (pH 7.4), yet each substrate induces similar high-spin heme content. For palmitate in low phosphate buffer concentrations, the rate constant of the first electron transfer is much larger than k (cat). The results suggest that phosphate has a specific effect in promoting the first electron transfer step, and that P450(BM3) could modulate Bacillus membrane morphology and fluidity via palmitate oxidation in response to the external phosphate concentration.

Contenidos de aceite y de los ácidos láurico y mirístico en frutos maduros de Roystonea regia colectados durante dos años / Oily contents and the lauric and myristic acids in mature fruits of Roystonea regia harvested for two year

INTRODUCCIÓN: el D004, un ingrediente activo promisorio en el tratamiento de la hiperplasia prostática benigna, se obtiene a partir del aceite del fruto de Roystonea regia (Kunth) OF Cook. Está compuesto por una mezcla de ácidos grasos libres que incluye los ácidos láurico y mirístico, ambos de gran interés por sus efectos farmacológicos. OBJETIVO: determinar la posible influencia de la época de colecta sobre el contenido de aceite y la concentración de los ácidos láurico y mirístico de los frutos de R regia. MÉTODOS: se colectaron cada mes, durante 2 años, frutos maduros de R regia en una población seleccionada. En las muestras secas y molidas se determinó el contenido de aceite gravimétricamente y el de ácidos grasos por cromatografía de gases. RESULTADOS: se encontraron diferencias estadísticas significativas en los contenidos de aceite y de los ácidos láurico y mirístico; no obstante, los contenidos determinados en todos los casos se mantuvieron dentro de las especificaciones calidad establecidas para el material vegetal. CONCLUSIONES: el material vegetal colectado durante todo el año puede ser empleado en la obtención del aceite de R. regia, materia prima empleada en la producción de D004

INTRODUCTION: D004, an promissory active ingredient in treatment and prevention of begnin prostatic hyperplasia, is obtained from the fruit oil of Roystonea regia (Kunth) OF Cook. It is composed by a mixture of free fatty acids including lauric and myristic acids, both very important by their pharmacological effects. OBJECTIVE: to determine the potential influence of harvest season on the oily content and the concentration of lauric and myristic acids from R regia fruits. METHODS: each month for two years, it was possible to collect mature fruits from R regia in a selected group. In dry and milled samples it was determined the oily content in a gravimetric way and that of fatty acids by gas chromatography. RESULTS: there were differences statistically significant in oily contents and of lauric and myristic acids; however, the contents determined in all the cases remained within the quality specifications established for the plant material. CONCLUSIONS: the plant material collected for all the year may be used in obtaining of R. regia oil, raw material used in the production of D004

Study on LDL adsorbent modified by lauric acid / 生物医学工程学杂志

A hydrophobic low-density lipoprotein cholesterol (LDL-C) adsorbent was synthesized with lauric acid and chitosan. The condition for adsorption was obtained by investigating the influence of adsorbent amount and adsorption time. The results of adsorption in vitro showed that the average adsorption rates for total cholesterol (TC), LDL-C, high-density lipoprotein cholesterol (HDL-C) and total protein (TP) were 47.7%, 84.7%, 18.1% and 5.9% respectively. The adsorbent possesses good selectivity in removing LDL-C.

Two new phenolic acids from Drynariae rhizoma / 药学学报

To study the chemical constituents of Drynariae Rhizoma, nine phenolic acids were isolated from a 70% ethanol extract by using a combination of various chromatographic techniques including column chromatography over silica gel, ODS, Sephadex LH-20, and semi-preparative HPLC. By spectroscopic techniques including 1H NMR, 13C NMR, 2D NMR, and HR-ESI-MS, these compounds were identified as 4, 4'-dihydroxy-3, 3'-imino-di-benzoic acid (1), protocatechuic acid (2), gallic acid (3), p-hydroxybenzoic acid (4), (E)-caffeic acid (5), ethyl trans-3, 4-dihydroxycinnamate (6), caffeic acid 4-O-beta-D-glucopyranoside (7), p-coumaric acid 4-O-beta-D-glucopyranoside (8), and 23(S)-12-O-caffeoyl-12-hydroxyllauric acid glycerol ester (9), separately. Among them, 1 and 9 are new compounds, and 3, 4, and 6 were isolated from Drynaria species for the first time.

Preparation, characterization, and pulmonary delivery of rifapentine liposomes modified by lauric diethanolamide / 药学学报

<p><b>AIM</b>To prepare rifapentine (RIF) liposomes modified by surfactants for studying their the water-solubility, drug loading effeciency, release rate and pulmonary drug delivery.</p><p><b>METHODS</b>The film method was used to prepare RIF liposomes. Of verious RIF liposomes morphology by lauric diethanolamide (LDEA), Tween 80 and azone, the properties were studied, envolving morphology, entrapment drug release rate and dissected lung-membrance penetration rate of swine. Pulmonary delivery study was carried out through bronchoscope.</p><p><b>RESULTS</b>The particle size of RIF-LDEA liposomes was between 15 - 50 nm. The top entrapment efficiency reached 83.0%. The apparent coefficient of membrane penetration (Kp) was 44.29. LD50 was 675 mg x kg(-1) by iv.</p><p><b>CONCLUSION</b>LDEA increased the water-solubility, loading effeciency and release rate of RIF liposomes. The prepared RIF-LDEA liposomes were suitable for the treatment of pulmonary tubrculosis through bronchoscope.</p>

A new rat model of cerebral infarction based on the injury of vascular endothelial cell / 中国结合医学杂志

<p><b>OBJECTIVE</b>A new rat model of cerebral infarction was developed to elucidate the contribution of vascular endothelial cell during focal cerebral infarction formation.</p><p><b>METHODS</b>Forty-eight Sprague-Dawley (SD) rats were randomly divided into the model group, sham operation group, and control group for indexes observation of triphenyltetrazolium chloride (TTC) dyeing, neurological deficit, plasma tissue-type plasminogen activator (tPA) activity, plasminogen activator inhibitor (PAI) activity, thromboxane B(2) (TXB(2)) content, and 6-keto-prostaglandin (6-keto-PGF(1alpha)) content.</p><p><b>RESULTS</b>(1) The highest neurological score appeared at 6 h after operation, descending significantly at sequential time. (2) Using TTC dyeing and optical microscope technique, pathological changes in brains were observed. (3) Compared with control group and sham operation groups, there was a decrease in tPA activity of model rats at the initial 12 h after injection of sodium laurate (P < 0.05), PAI activity decreased markedly in the model group at 24 h after injection of sodium laurate. (4) In plasma TXB(2) concentration reached the highest level compared at 6 h after injection of sodium laurate, but there were not obvious differences in plasma 6-keto-PGF(1alpha) concentration among all groups (P > 0.05).</p><p><b>CONCLUSION</b>Focal cerebral infarction in rats could be induced by some sodium laurate, showing ischemic cerebrum necrosis, function disorder of vascular endothelium-platelet, fibrinolysis abnormality. This model could play an important role in researching the contribution of vascular endothelial cell during cerebral infarction development, preventing and curing by traditional Chinese medicine.</p>

Studies on synthesis of polyhydroxyalkanoate consisting of 3-hydroxyvalerate by Aeromonas hydrophila / 生物工程学报

Polyhydroxyalkanoates (PHA) is a family of microbially synthesized polyesters consisting of various 3-hydroxyalkanoate monomers. Aeromonas hydrophila 4AK4 could be able to synthesize PHA copolymer consisting of 3-hydroxybutyrate (3-HB) and 3-hydroxyhexanoate (3-HHx). No data has been reported about the ability to synthesize the PHA with other monomers in A. hydrophila. In this study, propionic acid, valeric acid, heptanoic acid, nonanoic acid and undecanoic acid were used together with gluconate to find out whether A. hydrophila 4AK4 could synthesize the PHA consisting of odd carbon atom number monomers. The result showed that A. hydrophila 4AK4 could not growth when supplied with propionic acid, valeric acid, heptanoic acid and nonanoic acid and only undecanoic acid could be used to synthesize PHA. Wild type and recombinant A. hydrophila 4AK4 harboring phaA (beta-ketothiolase) and phaB (acetoacetyl-CoA reductase) were cultivated with undecanoic acid and glucose or undecanoic acid and gluconate served as carbon sources. PHA consisting of 3-HB and 3-hydroxyvalerate (3-HV) could be produced by both wild type and recombinant A. hydrophila 4AK4 and the latter could produce PHA with more 3-HB monomer. When the ratio of glucose or gluconate to undecanoic acid was 1:1, the cell dry weight (CDW) of A. hydrophila 4AK4 reached 1.14 g/L and PHA content was 60% of the CDW after cultivation for 24 h. When lauric acid and undecanoic acid were served as co-substrate, A. hydrophila 4AK4 could produce copolyester consisting of 3-HB, 3-HV and 3-HHx. Along with the increase of undecanoic acid proportion in the mixed carbon source, the 3-HV content of copolymer was increased while the 3-HB and 3-HHx content were decreased. In all cases, the CDW decreased along with the increase of undecanoic acid concentration, which indicated that undecanoic acid was not very good for A. hydrophila 4AK4 growth.

Fermentative production of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) by recombinant Aeromonas hydrophila 4AK4 (pTG01) / 生物工程学报

Copolyesters consisting of 3-hydroxybutyrate (3HB) and 3-hydroxyhexanoate (3HHx) (PHBHHx), a new type of biodegradable material, are receiving considerable attentions recently. The material properties are strongly related to the 3HHx fraction of PHBHHx. As the 3HHx fraction increase, crystallinity and melting point of PHBHHx decrease, flexibility and tractility increase. PHBHHx of different 3HHx fraction can meet different demands of commercial application and research. Aeromonas are the best studied PHBHHx-producing strains. Recent studies have been focused on optimizations of fermentative culture media and culture conditions for low-cost and efficient fermentative production. Aliphatic substrates such as long-chain fatty acid and soybean oil were used in the PHBHHx fermentation as the sole carbon source and energy source. Two-stage fermentation method was also developed for more efficient PHBHHx production. While studies on Aeromonas hydrophila revealed that the monomer composition of PHBHHx could not easily be regulated by fermentative process engineering methods such as changing substrates and fermentative conditions because precursors involved in the PHBHHx synthesis were all from the beta-oxidation pathway. In this study, phbA gene encoding beta-ketothiolase and phbB gene encoding acetoacetyl-CoA reductase were introduced into a PHBHHx-producing strain Aeromonas hydrophila 4AK4 so as to provide a new 3HB precursors synthesis way. phbA gene encodes beta-ketothiolase which can catalyze two acetyl-CoA to form acetoacetyl-CoA; phbB gene encodes acetoacetyl-CoA reductase catalyzing acetoacetly-CoA into 3HB-CoA which is the precursor of 3HB. The introduced novel 3-hydroxybutyrate precursor synthesis pathway allowed the recombinant strain to use unrelated carbon source such as gluconate to provide 3HB precursors for PHBHHx synthesis. Shake-flask experiments were carried out to produce PHBHHx of controllable monomer composition and fermentations in 5 L fermentor were also proceeded for confirmation of these result in large-scale culture. In flask culture, it was possible to reduce the 3HHx mol fraction in PHBHHx from 15 % in the wild type to 3% - 12% in the recombinant by simply changing the ratio of gluconate to lauric acid in the culture media. When lauric acid was used as the sole carbon source, 51.5 g/L Cell Dry Weight (CDW) containing 62 % PHBHHx with 9.7 % 3HHx mol fraction was obtained in 56 hours of fermentation in a 5 liter fermentor. When co-substrates of sodium gluconate and lauric acid (1:1) were used as carbon sources, 32.8 g/L CDW containing 52 % PHBHHx with 6.7% 3HHx mol fraction was obtained in 48 hours of fermentation. These results showed the possibility for fermentative production of PHBHHx with controllable monomer composition.

Photosensitization of cultured cells and viruses by pyrene lipids.

Administration of pyrene-linked fatty acids and lipids to cultured cells or an enveloped (vesicular stomatitis) virus induced photosensitization which, following irradiation with a long ultra-violet light (LUV), resulted in killing of the cells and loss of the infectivity of the virus with the following specific effects. (i) LUV illumination of the pyrene-sphingomyelin administered cultured skin fibroblasts derived from normal individuals and patients with Niemann-Pick disease permitted selective killing of the latter. (ii) Similarly LUV illumination of pyrenedodecanoic acid (P12) incubates of leukemic cell lines mixed with human bone marrow cells permitted selective killing of the former. (iii) LUV illumination of P12 incubates of vesicular stomatitis virus decreased the infectivity of the virus by up to 12 logs.