A novel prodrug of salicylic acid, salicylic acid-glutamic acid conjugate utilizing hydrolysis in rabbit intestinal microorganisms.

The fate of salicylic acid-glutamic acid conjugate (salicyl-glutamic acid) following oral, intravenous, intracecal and rectal administration (60, 10, 5 and 5 mg/kg, respectively: salicylic acid equivalent) was examined in rabbits. Salicylic acid was detected in the blood 2 h after oral administration of salicyl-glutamic acid and it reached the maximum level (69.4 micrograms/ml) at 18 h after the dose. A high blood concentration of salicylic acid (24.8 micrograms/ml) was observed up to 36 h. But only a small amount of salicyl-glutamic acid was detected in the blood (less than 2.5 micrograms/ml, as salicylic acid). In contrast, unchanged salicyl-glutamic acid was found mainly in the blood following intravenous administration of salicyl-glutamic acid, suggesting that presystemic de-conjugation of salicyl-glutamic acid predominantly occurred. The intestinal mucosal de-conjugation of salicyl-glutamic acid was negligible in the in situ intestinal sac preparation with complete mesenteric venous blood collection. Immediate and very extensive salicylic acid formation in the cecum was found following intracecal administration of salicyl-glutamic acid. After oral pretreatment of rabbits with kanamycin sulfate (6 x 400 mg), a significant inhibition of salicylic acid formation following intracecal administration of salicyl-glutamic acid was observed, indicating that the intestinal microorganisms were responsible for the biotransformation of salicyl-glutamic acid. Also, in vitro incubation of salicyl-glutamic acid with gut contents showed that the primary location of hydrolysis was the hind gut.     

Determination of oleanolic acid and ursolic acid in cornel by cyclodextrin-modified micellar electrokinetic chromatography

A cyclodextrin-modified micellar electrokinetic chromatography (CD-MEKC) method was established for the determination of oleanolic acid and ursolic acid in cornel. The two components were separated in the running buffer of 40 mmol/L sodium borate containing 5% methanol, 25 mmol/L SDS and 15 mmol/L hydroxypropyl-beta-cyclodextrin (HP-beta-CD). The applied voltage was 24 kV. The wavelength of detection was 200 nm. The temperature was kept at 25 C. Cinnamic acid was used as the internal standard. The analytical performance of the method was tested with respect to linearity, precision and recovery. The calibration curves were linear in the range of 10.15-243.6 microg/mL, r=0.9993 (oleanolic acid) and 10.07-241.7 microg/mL, r=0.9994 (ursolic acid); the intra-day precision (RSD) was less than 3.7% (oleanolic acid) and 4.1% (ursolic acid); the inter-day precision (RSD) was less than 4.2% (oleanolic acid) and 4.9% (ursolic acid). The limits of detection were 1.6 microg/mL for both components. The method proved to be sensitive, rapid, accurate and suitable for the determination of oleanolic acid and ursolic acid in cornel.     

Assay of free ferulic acid and total ferulic acid for quality assessment of Angelica sinensis

Activity of Chinese Danggui (DG), the processed root of Angelica sinensis (Oliv.) Diels, is linked to the ferulic acid content but the stability of ferulic acid during extraction for medicinal use is not known. The stabilities of ferulic acid and coniferyl ferulate were evaluated in the extracts of DG using a variety of extraction solvents. These included various combinations and proportions of methanol, water, formic acid, 1 M aqueous hydrochloric acid and 2% sodium hydrogen carbonate (NaHCO3) in water. Coniferyl ferulate was found liable to hydrolyze into ferulic acid in neutral, strongly acidic and basic solvents, where heat and water could facilitate this hydrolysis. However, the hydrolysis was relatively resisted in weakly organic acid. Based on the stability evaluation, two new terms, namely: free ferulic acid and total ferulic acid, were suggested and defined. Free ferulic acid refers to the natural content of ferulic acid in herbs. Total ferulic acid means the sum of free ferulic acid plus the amount of related hydrolyzed components. Meanwhile, the high-performance liquid chromatographic (HPLC) method was developed to assay free ferulic acid and total ferulic acid in DG using methanol-formic acid (95:5) and methanol-2% NaHCO3 in water (95:5) as extraction solvents, respectively. Ten DG samples were investigated on their contents of free and total ferulic acid. The results indicated that the amount variety of free ferulic acid was larger than that of their counterparts, and the ratio of total ferulic acid to free ferulic acid was 4.07 +/- 2.73 (mean +/- SD, n = 10). The chemical assay of DG using total ferulic acid content would be a better choice to assess the herbal quality and was recommended.     

A comparative study of the radical-scavenging activity of the phenolcarboxylic acids caffeic acid, p-coumaric acid, chlorogenic acid and ferulic acid, with or without 2-mercaptoethanol, a thiol, using the induction period method

Phenolcarboxylic acid antioxidants do not act in vivo as radical-scavengers in isolation, but rather together with GSH (glutathione), a coantioxidant, they constitute an intricate antioxidant network. Caffeic acid, p-coumaric acid, ferulic acid and chlorogenic acid with or without 2-mercaptoethanol (ME), as a substitute for GSH, was investigated by the induction period (IP) method for polymerization of methyl methacrylate (MMA) initiated by thermal decomposition of 2,2'-azobisisobutyronitrile (AIBN, a source of alkyl radicals, R(.)) and benzoyl peroxide (BPO, a source of peroxy radicals, PhCOO(.)) using differential scanning calorimetry (DSC). Upon PhCOO(. )radical scavenging, the stoichiometric factors (n, number of free radical trapped by one mole of antioxidant) for caffeic acid, ferulic acid, p-coumaric acid and chlorogenic acid were 2.4, 1.8, 1.7 and 0.9, whereas upon R(.) radical scavenging, the corresponding values were 1.3, 1.2, 1.0 and 0.8, respectively. Antioxidants with n values close to 2 suggest the stepwise formation of semiquinone radicals and quinones. By contrast, those with n values close to 1 suggest the formation of dimers after single-electron oxidation, possibly due to recombination of corresponding aryloxy radicals. The ratio of the rate constant of inhibition to that of propagation (k(inh)/k(p)) declined in the order chlorogenic acid > p-coumaric acid > ferulic acid > caffeic acid. The ratio of the observed IP for the phenolcarboxylic acid/2-mercapto-ethanol (ME) mixture (1:1 molar ratio) (A) to the calculated IP (the simple sum of phenol acid antioxidant and ME) (B) was investigated. Upon R(.) scavenging, the caffeic acid or p-coumaric acid/ME mixture was A/B > 1, particularly the former was 1.2, suggesting a synergic effect. By contrast, upon PhCOO(.) scavenging, the corresponding mixture was A/B < 1, particularly the latter was 0.7, suggesting an antagonistic effect. Upon both radicals scavenging, the A/B for the ferulic acid or chlorogenic acid/ME mixture was approximately 1. The reported beneficial antioxidant, anti-inflammatory and anticancer effects of caffeic acid and p-coumaric acid may be related to their prooxidant-antioxidant balance in the presence of GSH.     

离子排斥色谱法同时测定果汁中11种有机酸

 用离子排斥色谱法实现了对果汁中 11种有机酸 (草酸、柠檬酸、酒石酸、苹果酸、抗坏血酸、乳酸、琥珀酸、甲酸、乙酸、戊二酸、富马酸 )的分离测定。以 17mmol/L硫酸为淋洗液 ,样品在ICE ION 30 0离子排斥柱上分离后 ,用紫外检测器在 2 10nm处测定其中的有机酸。各组分质量浓度测定的相对标准偏差在 1.5 %～ 9.8% (n =10 )。     

太阳能热电耦合合成苯甲酸

通过恒电位电解甲苯实现了苯甲酸的太阳能热电耦合合成, 考察了电极材料、 反应温度及电解电压对苯甲酸合成的影响. 采用气相色谱、 红外光谱和紫外光谱对电解产物进行分析检测, 证实了太阳能热电氧化甲苯的主要产物为苯甲酸. 实验结果表明, 以石墨作为阳极材料, 反应温度为90 ℃, 电解电压为2.0 V时, 氧化甲苯合成苯甲酸的产率可达51.6%.     

Gold- and gold-palladium/poly(1-vinylpyrrolidin-2-one) nanoclusters as quasi-homogeneous catalyst for aerobic oxidation of glycerol

Glycerol was oxidized catalytically under aerobic conditions in the presence of monometallic nanoclusters of gold on poly(1-vinylpyrrolidin-2-one) (PVP) to give hydroxymalonic acid (tartronic acid) as the major product, together with 2,3-dihydroxypropanoic acid (glyceric acid) and hydroxyacetic acid (glycolic acid) as minor products. In contrast, oxalic acid was selectively obtained when bimetallic Au-Pd:PVP nanoclusters were used as the catalyst.     

高效液相色谱法测定毛樱桃中维生素C含量

建立了高效液相色谱(HPLC)测定毛樱桃中维生素C的主要成分L-抗坏血酸和D-异抗坏血酸的方法. 以0.05 mol/L磷酸溶液∶甲醇(体积比为98∶2)作为流动相,紫外检测波长245 nm,柱温25 ℃,流速0.70 mL/min. 获得L-抗坏血酸、D-异抗坏血酸标准曲线线性较好(r为1.0),精密度(RSD)为0.6%. L-抗坏血酸加标回收率为90.83%~92.52%,D-异抗坏血酸加标回收率为91.93%~92.99%. 试验结果表明,方法测定维生素C操作简单、提取速度快、灵敏度高、回收率好,测得L-抗坏血酸的含量为8.24 mg/100 g,D-异抗坏血酸未检测出. 方法可适用于检测其他与毛樱桃相似的果蔬中L-抗坏血酸、D-异抗坏血酸的含量.     

反相高效液相色谱法测定饲料添加剂阿散酸中的阿散酸及掺假物质对氨基苯磺酸

建立了用于饲料添加剂阿散酸质量控制的反相高效液相色谱法。采用的色谱条件: Waters Bondapak C18柱(150 mm×4 mm, 5 μm)分离,以甲醇-水(用稀磷酸调节pH至2.9) (1:4, v/v)作流动相,流速1.0 mL/min,紫外检测波长为244 nm。在优化的色谱条件下,阿散酸和掺假物质对氨基苯磺酸在3 min内实现了基线分离。阿散酸和对氨基苯磺酸的线性范围均为5～200 mg/L,检出限(S/N=3)分别为0.20 mg/L和0.15 mg/L。该方法简便快速,适合饲料添加剂阿散酸的分析以及监测对氨基苯磺酸掺假。     

Permanganate-based chemiluminescence analysis of ferulic acid using flow injection.

A simple, sensitive and rapid flow-injection chemiluminescence method has been developed for the determination of ferulic acid based on the chemiluminescence reaction of ferulic acid with potassium permanganate in a nitric acid medium. A strong chemiluminescence signal was observed when ferulic acid was injected into an acidic potassium permanganate solution in a flow-cell. The present method allowed the determination of ferulic acid in the concentration range of 6.0 x 10(-6) to 2.0 x 10(-4) mol l(-1); the detection limit (3sigma) for ferulic acid was 9.6 x 10(-8) mol l(-1). The relative standard deviation was 1.0% for 11 replicate analyses of 2.0 x 10(-4) mol l(-1) ferulic acid. The proposed method was applied to the determination of ferulic acid in real samples with satisfactory results. Moreover, the reaction mechanism of the chemiluminescence system was primarily considered.     

Chemiluminescence determination of ferulic acid by flow-injection analysis using cerium(IV) sensitized by rhodamine 6G

A simple, sensitive and rapid flow-injection chemiluminescence method has been developed for the determination of ferulic acid based on the chemiluminescence reaction of ferulic acid with rhodamine 6G and ceric sulfate in sulphuric acid medium. Strong chemiluminescence signal was observed when ferulic acid was injected into the acidic ceric sulfate solution in a flow-cell. The present method allowed the determination of ferulic acid in the concentration range of 8.0x10(-6) to 1.0x10(-4)moll(-1) and the detection limit for ferulic acid was 8.7x10(-9)moll(-1). The relative standard deviation was 2.4% for 10 replicate analyses of 1.0x10(-5)moll(-1) ferulic acid. The proposed method was applied to the determination of ferulic acid in Taita Beauty Essence samples with satisfactory results.     

Synthesis of gallic acid: Cu(2+)-mediated oxidation of 3-dehydroshikimic acid

With the elaboration of high-yielding, high-titer syntheses of 3-dehydroshikimic acid from glucose using recombinant Escherichia coli, oxidation of this hydroaromatic becomes a potential route for synthesis of gallic acid. Conversion of 3-dehydroshikimic acid into gallic acid likely proceeds via initial enolization of an alpha-hydroxycarbonyl and oxidation of the resulting enediol. 3-Dehydroshikimate enolization in water was catalyzed by inorganic phosphate while Zn(2+) was used to catalyze enolization in acetic acid. Enediol oxidation employed Cu(2+) as either the stoichiometric oxidant or as a catalyst in the presence of a cooxidant. Gallic acid was produced in a yield of 36% when 3-dehydroshikimic acid in phosphate-buffered water reacted for 35 h with H2O2 and catalytic amounts of CuSO(4). 3-Dehydroshikimate-containing, phosphate-buffered culture supernatants reacted with stoichiometric amounts of CuCO(3)Cu(OH)(2) and Cu(x)(H(3-x)(PO4)(2) to give gallic acid in yields of 51% in 5 h and 43% in 12 h, respectively. Solutions of 3-dehydroshikimic acid in acetic acid reacted with stoichiometric amounts of Cu(OAc)(2) to afford a 74% yield of gallic acid in 36 h. Acetic acid solutions of 3-dehydroshikimic acid could also be oxidized by air using catalytic quantities of Cu(OAc)(2). ZnO accelerated these oxidations leading to a 67% yield of gallic acid in 4 h when an acetic acid solution of 3-dehydroshikimic acid was reacted with O(2) and a catalytic amount of Cu(OAc)(2).     

Preparation of poly (styrene‐co‐allyl sulfonic acid) as a novel catalyst for the alcoholysis of dioscin

This work describes the preparation of a novel solid acid, poly (styrene‐co‐allyl sulfonic acid) (St‐SAA), and its activity test for extracting diosgenin from Dioscorea Zingiberensis C.H. Wright (DZW). The solid acid was synthesized by the radical polymerization of styrene and sodium allyl sulfonate in water/ethanol solution, followed by the acidification. The prepared solid acid was characterized by infrared spectrum (FTIR), thermogravimetric analysis (TGA), X‐ray photoelectron spectroscopy (XPS), element analysis, and scanning electron microscope. The solid acid catalyst was used to extract diosgenin from DZW. It was found that the alcoholysis activity of the solid acid was higher than the hydrolysis activity of sulfuric acid with the same mass under the same conditions. Besides, the solid acid can be separated from the reaction mixture for the recycling extraction of diosgenin, and the solid acid has no loss of mass and no decrease of alcoholysis activity after repeated cycles.     

Analysis of polynitrophenols and hexyl by liquid chromatography-mass spectrometry using atmospheric pressure ionisation methods and a volatile ion-pairing reagent

An LC-MS method for the determination of picric acid (2,4,6-trinitrophenol), its reductive transformation products picramic acid (2-amino-4,6-dinitrophenol) and iso-picramic acid (4-amino-2,6-dinitrophenol) and hexyl (2,2',4,4',6,6'-hexanitrodiphenylamine) has been developed. The analytes were separated using ion-pairing chromatography with a volatile ion-pairing reagent suitable for subsequent MS detection. The performance of an atmospheric pressure chemical ionisation (APCI) and an electrospray ionisation (ESI) interface was compared. ESI-MS is more sensitive for the analytes, especially for hexyl and picric acid, APCI-MS delivered more fragments necessary for unequivocal identification. With LC-ESI-MS limits of detection using single ion monitoring (SIM) mode are 4 ng (iso-picramic acid), 800 pg (picramic acid), 400 pg (picric acid) and 80 pg (hexyl). For quantification, 15N-picric acid was used as an internal standard. Using this new method, the degradation of picric acid in soil was monitored in a laboratory study. Furthermore, the presence of picramic acid was for the first time verified in soil samples from a former ammunition plant.     

Isolierung,Konstitution und Synthese der (R)-(−)-Eucominsäure

From the bulbs of Eucomis punctata L'Hérit. (Liliaceae) and of a hitherto undefined species of Eucomis a new optically active phenolic carboxylic acid, eucomic acid, was isolated. Structure 1 was assigned on the basis of chemical and spectral evidence. The absolute configuration of eucomic acid was determined by its correlation with piscidic acid ((2 R, 3 S)-2-(4′-hydroxybenzyl)-tartaric acid) ( 8 ). Consequently, eucomic acid is (R)-(?)-2-(4′-hydroxybenzyl)-malic acid ( 1 ). For the stereospecific synthesis, methyl cis-p-methoxybenzylidene-succinic acid ( 22 ) was transformed into the γ-lactone 24 which, by catalytic hydrogenolysis, yielded (±)-2-(4′-hydroxybenzyl)-malic acid 1-methyl ester ( 27 ). Resolution with (?)-quinine led to the enantiomeric acids 29 and 30 . The methyl ester of the levorotatory enantiomer 30 was identical with the dimethyl ester 3 of 4′-O-methyl-eucomic acid.     

Zur Synthese sulfonierter Derivate von 4- und 5-Aminoindan

On the Synthesis of Sulfonated Derivatives of 4- and 5-Aminoindan Baking the hydrogensulfate salt of 4-aminoindan (1) and 5-aminoindan (2) led, respectively, to 4-aminoindan-7-sulfonic acid (3) and 5-aminoindan-6-sulfonic acid (4). Acid 4 was also obtained by direct sulfonation of 2. 4-Aminoindan-6-sulfonic acid (5) and 6-aminoindan-4-sulfonic acid (6) were prepared by sulfonation of 4-nitroindan (7) and 5-nitroindan (9) , respectively, to 4-nitroindan-6-sulfonic acid (8) and 6-nitroindan-4-sulfonic acid (10) , followed by a Béchamp-reduction. Treatment of 1 with amidosulfuric acid gave 3 , whereas the same reaction with 2 led to a mixture of 4 and 5-aminoindan-4-sulfonic acid (11). Independent synthesis of 11 was achieved by the following sequence of reactions: sulfur dioxide treatment of the diazonium chloride derived from 4-amino-5-nitrodan (13) gave 5-nitroindan-4-sulfonyl chloride (14) ; hydrolysis to 5-nitroindan-4-sulfonic acid (15) , and final reduction. The 4-aminoindan-5-sulfonic acid (16) was synthesized by treatment of 4-amino-7-bromoindan (18) with amidosulfuric acid to give 4-amino-7-bromoindan-5-sulfonic acid (19) followed by hydrogenolysis. Sulfonation of 4-acetyl-amino-7-bromoindan (17) with oleum followed by hydrolysis led to 7-amino-4-bromoindan-5-sulfonic acid (20) , the structure of which was confirmed by reductive dehalogenation to 5 .     

用GC-MS法分析柿树叶中的脂肪酸

用乙醚－己烷混合溶剂抽提柿树叶中的脂肪酸,ＮａＯＨ－ＣＨ３ＯＨ交换法甲酯化,毛细管柱ＦＦＡＰ作为分离柱,进行气相色谱－质谱法测定脂肪酸（以甲酯的形式）的组成。共分离出２１种脂肪酸,鉴定出１９种,占总含量的９８．７２％,其中以肉豆蔻酸（６．６８％）、棕榈酸（３０．００％）、硬脂酸（１０．４２％）、十六碳三烯酸（１．４４％）、亚油酸（１．８４％）、十八碳－烯酸（２２．２２％）、亚麻酸（１．２５％）、花     

在线酸坝富集-毛细管区带电泳法测定槐角中的染料木素

建立了分离测定槐角提取液中染料木素的在线酸坝富集-毛细管区带电泳方法,考察了酸的种类、酸的及浓度、进样/进酸时间比例等因素对堆积效率的影响.实验以20mmol/L硼砂(pH 10.5)作为缓冲溶液,200mmol/L柠檬酸溶液(pH 1.7)作为酸坝,进样、进酸时间分别为180s和45s,在分离电压15kV,检测波长2...     

Oil composition and some morphological characters of Crambe orientalis var. orientalis and Crambe tataria var. tataria from Turkey

Native Crambe orientalis var. orientalis and Crambe tataria var. tataria collected from Kahramanmaras flora were morphologically examined and seed oil composition was determined. Volatile acid and fatty acid composition of seeds were examined with GC and GC/MS and the ratio of volatile acids to total oil was 3.49% in C. orientalis and 17.49% in C. tataria. The ratio of fatty acids to total oil was 92.03 and 67.28% in C. orientalis, and C. Tataria, respectively. The amount of erucic acid was 39.29% in C. orientalis and 29.87% in C. tataria. High linolenic acid (21.21%) and linoleic acid (12.42%) was found in C. orientalis oil, and high linolenic acid (15.01%) and linoleic acid (9.00%) was also found in C. tataria oil.     

固相萃取-高效液相色谱法测定蜂蜜中的有机酸

建立了固相萃取-高效液相色谱(SPE-HPLC)同时测定蜂蜜中5种有机酸(L-苹果酸、马来酸、琥珀酸、柠檬酸、D-苹果酸)含量的方法。蜂蜜经制样后过Bond Elutes SAX固相萃取(SPE)小柱净化,用C18-MS-II反相色谱柱(250 mm×4.6 mm, 5 μm)进行分离,流动相为2%偏磷酸溶液,流速为0.7 mL/min,检测波长为210 nm。在此条件下5种有机酸在相应的线性范围内其线性相关系数均大于0.9967;方法的回收率为86.0%～103.9%,相对标准偏差为5.7%～9.8%(n=6),检出限为0.06～9.4 mg/kg。所建立的方法可用于蜂蜜样品中有机酸的测定。