奎尼酸的生物合成与应用

奎尼酸是一种具有极高价值的精细化工产品和医药中间体,在医药、食品、化工等行业均有广泛的应用价值。奎尼酸广泛存在于多种植物中,其咖啡酰类衍生物在抗病毒、治疗心血管疾病等研究中得到越来越多的关注和应用。目前获得奎尼酸的方法主要有4种,即植物提取法、化学合成法、酶工程法和微生物发酵法。随着分子生物学的不断发展,结合现代生物技术,应用基因工程方法,必将成为获得奎尼酸的重要途径。本文综述奎尼酸的分布、生物合成及其应用。     

Distribution of quinic acid derivatives and other phenolic compounds in Brazilian propolis

The quinic acid derivatives (including 4-feruoyl quinic and 5-ferruoyl quinic acids characterized for first time in propolis samples) and other phenolic compounds were quantified in thirteen Brazilian propolis samples by HPLC analysis. For chemometrical analysis, the distribution of quinic acid derivatives and other phenolic compounds were considered. The results suggest that the Brazilian propolis with floral origin from Citrus sp. have the highest concentration of the quinic acid derivatives (between 11.0 to 58.4 mg/mg of the dried crude hydroalcoholic extract) and therefore would probably show a more effective hepatoprotective activity.     

Inhibitory effects of chlorogenic acid and its related compounds on the invasion of hepatoma cells in culture

Actions of chlorogenic acid, a major component of coffee, andits constituents, caffeic and quinic acids, on theproliferation and invasion of AH109A, a rat ascites hepatomacell line, were investigated using in vitro assay systems. Allthree components suppressed the AH109A invasion atconcentrations of 5–40 M without altering the cellproliferation. At the concentration of 10 M, chlorogenic,caffeic and quinic acids significantly (P < 0.05) suppressedthe invasion by 68%, 36% and 31%, respectively, implying thatthe suppressive effect of chlorogenic acid on the AH109Ainvasion might result from the additive effects of itsconstituents, caffeic and quinic acids. At the concentrationof 10 M, cinnamic acid and p-coumaric acid (4-hydroxycinnamicacid) exerted no or little influence on the invasion, whereascaffeic acid (3,4-dihydroxycinnamic acid) significantly (P <0.05) suppressed it, suggesting the possible involvement ofthe 3,4-dihydroxy group of caffeic acid in the suppression.Chlorogenic acid was thus demonstrated to be one of thechemical entities in coffee suppressing the hepatoma invasionin vitro, and both of its constituents, caffeic and quinicacids, to be responsible for the anti-invasive activity. Theseresults suggest the existence of nutritionally andpharmacologically important substances in coffee which controltumor cell invasion.     

Occurrence of shikimic and quinic acids in angiosperms

Leaves of 83 angiosperms have been made surveyed for quinic and shikimic acids. The quinic acid content was higher in woody dicotyledons than in herbaceous dicotyledons or in the monocotyledons, substantiating the view that its presence may be correlated with the lignification in plants.     

Application of fast atom bombardment mass spectrometry to chlorogenic acids

The technique of positive- and negative-ion fast atom bombardment mass spectrometry has been shown to be capable of producing molecular mass and useful fragmentation information for the structural elucidation of chlorogenic acids. The mass spectra of chlorogenic acid and the related compounds 3′-O-methylchlorogenic acid, neochlorogenic acid, 4,5-dicaffeoyl quinic acid and 1,5-dicaffeoyl quinic acid are compared with those obtained by electron impact mass spectrometry.     

Changes in bulk protein of tobacco leaves on aerobic autolysis: Hydrogenation studies and identification of bound quinic acid

During aerobic autolysis and in commercial curing, the bulk proteins of tobacco leaves become coupled with quinic acid, presumably in consequence of coupling of chlorogenic acid congeners with lysine ε-NH₂ groups. Quinic acid derivatives, prepared from acid hydrolysates of such altered proteins, were identified by GC-MS. Such proteins were also hydrogenated over Rh/Al₂O₃ with a view to stabilizing the hypothetical linkages. Difficulties in removing contaminant Al had to be overcome. Evidence was then obtained (by GLC of derivatives) for several components, in acid hydrolysates of hydrogenated altered proteins, which were neither normal hydrogenation products of the common amino acids nor derivatives of quinic acid. Details of the chromatograms and mass spectra of quinic acid derivatives are provided in a supplementary publications.     

Effects of Two Potential Allelochemicals on the Photosystem II of <i>Nitzschia closterium</i> and<i> Monostroma nitidum</i>

In aquaculture, high-density seaweed farming brings higher economic benefits but also increases outbreaks of diatom felt. The effective control of diatom felt in high-density seaweed farming has always been a research hotspot. This study selected two potential allelochemicals 2-hydroxycinnamic acid and quinic acid to explore their effects on a diatom Nitzschia closterium and an economic seaweed Monostroma nitidum. The results showed that 2-hydroxycinnamic acid had better inhibitory effects than quinic acid on the growth, pigment content and photosynthetic efficiency of N. closterium. Their half-maximal inhibitory concentrations at 120 h (IC_{50–120 h}) were 0.9000 and 1.278 mM, respectively. Additionally, these allelochemicals had limited inhibitory effects on the growth, pigment content and photosynthetic efficiency of M. nitidum before 24 h. To further explore the allelopathic effect of these chemicals, this study focused on the photosystem II energy fluxes of N. closterium. It was found that 3 mM 2-hydroxycinnamic acid could destroy the whole photosynthetic system by devastating the PSII reaction centre (RC) before 24 h; however, the same concentration of quinic acid could only down-regulate the electron transport efficiency by changing the effective antenna size of an active RC and downregulating the PSII reaction centre density. These experimental results are expected to provide a new strategy to control diatom felt blooms on the high-density seaweed farming areas.     

枇杷果肉有机酸组分及有机酸在果实内的分布

用高效离子交换色谱（HPIC）测定了枇杷（Eriobotrya japonica Lindk）18个品种（小毛枇杷、夹脚、卓南1号、解放钟、富阳、森尾早生、华宝2号、香钟10号、白花、土肥、多宝2号、乌躬白、洛阳青、茂木、早钟6号、白梨、塘头4号和长红3号）的成熟果肉和2个品种（解放钟和早钟6号果）成熟果实不同组织有机酸含量。结果表明,成熟果肉中均含有苹果酸、奎尼酸、柠檬酸、异柠檬酸、α-酮戊二酸、富马酸、草酰乙酸、酒石酸8种有机酸,有的还含有微量的阿魏酸、顺乌头酸和B一香豆酸。大多数品种果肉中苹果酸含量最高,平均含量为4399mg kg^-1 FW,占总酸的62．7％;其次是奎尼酸,其平均含量为2042mgkg—FW,占总酸的29．1％。品种之间可滴定酸和有机酸含量差异很大。通过对果肉可滴定酸进行聚类分析,可把18个枇杷品种分为五个组群：极高酸（小毛枇杷）、高酸（夹脚、卓南1号、解放钟和富阳）、中酸（森尾早生、华宝2号、香钟10号、白花、土肥和多宝2号）、低酸（乌躬白、洛阳青、茂木和早钟6号）和极低酸（白梨、塘头4号和长红3号）。解放钟和早钟6号果肉和果皮的总酸含量及可滴定酸均无显著差异,但果皮和果肉的总酸含量和可滴定酸均大大高于种子。相似于果肉,果皮和种子的主要有机酸也是苹果酸和奎尼酸。果皮中苹果酸含量远高于奎尼酸,但种子中苹果酸含量比奎尼酸稍低。此外,种子中苹果酸和奎尼酸比果肉和果皮中的低得多。     

Quinic acid derivatives from Saussurea triangulata attenuates glutamate-induced neurotoxicity in primary cultured rat cortical cells

The leaves of Saussurea triangulata (Compositae) have been eaten with rice as a wrapping vegetable for preventing neuro-aging. However, the components responsible for the neuroprotective effects of S. triangulata still remain unidentified. In the process of investigating the neuroprotective activity of S. triangulata, we found that a methanol extract of S. triangulata exhibited significant protection against glutamate-induced toxicity in primary cultured rat cortical cells. Three quinic acid derivatives were isolated from the n-BuOH fraction of S. triangulata. Among these three quinic acid derivatives, methyl 5-caffeoylquinic acid (3) exhibited significant neuroprotective activities against glutamate-induced toxicity exhibiting cell viability of about 50%, at concentrations ranging from 0.1 μM to 10 μM. Therefore, the neuroprotective effect of S. triangulata might be due to the inhibition of glutamate-induced toxicity by the quinic acid derivatives from S. triangulata.     

A Microcolorimetric Method for the Determination of Quinic Acid and its Content in Flue-cured Tobacco

The colored compound produced by the reaction of periodate oxidation product of quinic acid with sodium nitroprusside and piperazine can be used as a quantitative measure of the quinic acid. The curve is linear for the acid examined in the range of 25 to 150,μg of quinic acid per 1 ml. Hence, the reaction provides a convenient method for the determination of the micro quantities of quinic acid obtained from tobacco extracts fractionated by chromatography on paper or ion exchange-resin column. The content of quinic acid in flue-cured tobacco was 0.23 per cent to dry matter.     

The enzymic conversion of hydroxycinnamic acids to p-coumarylquinic and chlorogenic acids in tomato fruits

Two enzymes thought to be involved in the biosynthesis of chlorogenic acid have been separated and purified by ion exchange chromatography and their properties studied. These two enzymes, p-coumarate CoA ligase and hydroxycinnamyl CoA: quinate hydroxycinnamyl transferase, acting together catalyse the conversion of p-coumaric acid to 5′-p-coumarylquinic acid and of caffeic acid to chlorogenic acid. The ligase has a higher affinity for p-coumaric than for caffeic acid and will in addition activate a number of other cinnamic acids such as ferulic, isoferulic and m-coumaric acids but not cinnamic acid. The transferase shows higher activity and affinity with p-coumaryl CoA than caffeyl CoA. It also acts with ferulyl CoA but only very slowly. The enzyme shows high specificity for quinic acid; shikimic acid is esterified at only 2% of the rate with quinic acid and glucose is not a substrate. The transferase activity is reversible and both chlorogenic acid and 5′-p-coumarylquinic acids are cleaved in the presence of CoA to form quinic acid and the corresponding hydroxycinnamyl CoA thioester.     

Quinate:NAP(P)+-oxidoreductase from Larix sibirica: purification,characterization and function

Quinate:NAP(P)⁺-oxidoreductase (QORase, EC 1.1.1.24), which catalyzes the interconversion of quinic and 3-dehydroquinic acids, was purified from the needles and developing xylem cells of Larix sibirica. The enzymes from these two tissues were partially characterized and compared. QORase from needles had optimum pH at 9.0 and apparent K_m values of 1.84 mM for quinic acid and 0.19 mM for NADP⁺. The enzyme was activated by phosphoenolpyruvate. Gallic and protocatechuic acids were formed in a reaction mixture of purified enzyme from needles as final products of quinic acid transformation. QORase from developing xylem cells showed pH optimum at 10.0 and had apparent Km values of 0.70 mM for quinic acid and 0.05 mM for NADP⁺. The enzyme was not affected by PEP. The divalent cations Co²⁺ and Mn²⁺ at least doubled activity of QORase from both sources but Mg²⁺ affected the enzyme from needles only. The spatial organization and regulation of quinic acid metabolism in the autotrophic and heterotrophic cells of conifers and the role of QORase in this process are discussed.     

The effect of chlorogenic, gallic and quinic acids on the growth of spoilage strains of Lactobacillus collinoides and Lactobacillus brevis

The naturally occurring complex organic acids, chlorogenic acid, gallic acid and quinic acid, at concentrations of 100, 500 and 1000 mg l^-1 were evaluated for effects on the growth of three spoilage strains of Lactobacillus collinoides and one of Lact. brevis in acid tomato broth containing 5% (v/v) ethanol at pH 4.8. During early stages of growth, all the complex acids at each concentration stimulated growth of Lact. collinoides but not of Lact. brevis. During stationary phase, chlorogenic and gallic acids produced greater cell densities of all strains, whereas quinic acid generally had less effect. The presence of these complex acids in fruit products may increase the requirement for added preservative in order to prevent spoilage by certain strains of lactic acid bacteria.     

The Oxidation of Quinic Acid

1. It is shown by means of filter-paper chromatograms preparedat intervals during the oxidation of quinic acid by hydrogenperoxide that at least six acids appear in the reaction liquid. 2. One of these acids is shown to be citric acid, and the oxidationof citric acid is shown to account for a further two of theacids resulting from the oxidation of quinic acid. 3. After prolonged oxidation (by H₂O₂) of both quinic and citricacids one acid predominates. This acid is proved by isolationand characterization to be malonic acid. 4. Evidence is produced which suggests that acetonedicarboxylicacid is an intermediate in the oxidation of citric acid (and,therefore, of quinic acid) to malonic acid     

Two new quinic acid derivatives from the fruits of Chaenomeles speciosa

Two new quinic acid derivatives (1, 2), together containing eighteen (3–20) known compounds, were isolated from the fruits of Chaenomeles speciosa. Spectroscopic methods and previous data retrieved from the literature were used to determine the chemical structures of the compounds. Among the compounds, quinic acid derivatives (3, 4, 6, 7), phenolic acid compounds (8, 10, 11) and catechin derivatives (18, 19, 20) were isolated for the first time from the family Chaenomeles. The chemotaxonomic significance of the compounds was also discussed.     

Metabolism of shikimic,quinic, and cyclohexanecarboxylic acids in germfree,conventional, and gnotobiotic rats

By using a new high-pressure liquid chromatography assay, the increase in urinary hipprate following ingestion of shikimic, quinic, and cyclohexanecarboxylic acid was studied to quantitate the extent of aromatization in germfree, gnotobiotic, and converitonal rats. Germfree rats aromatized 2% of a single dose of shikimic acid or quinic acid and 44% of cyclohexanecarboxylic acid. Conventional rats aromatized all three compounds; shikimic (12%), quinic (12%), and cyclohexanecarboxylic acid (61%). A human fecal flora was fed to otherwise germfree rats to determine the degree of association and the resulting effect upon the metabolism of shikimic, quinic, and cyclohexanecarboxylic acids in vivo. Following establishment of the human microflora and subsequent feedings of shikimic or quinic acids, excretion of urinary hippurate was five to seven times greater (10–15% of the dose) than in germfree rats fed the same acids. The results suggest that the intestinal flora is needed to metabolize the shikimic acid to substrate(s) (probably cyclohexanecarboxylic acid). This substrate can then be aromatized by mammalian enzymes.     

Annual changes in the concentration of minerals and organic compounds of Quercus suber leaves

Mature leaves are the primary source of sugars, which give rise to many secondary metabolites required for plant survival under adverse conditions. In order to study the interaction of field‐grown cork oak (Quercus suber L.) with the environment, we investigated the seasonal variation of minerals and organic metabolites in the leaves, using inductively coupled plasma atomic emission spectrometry, elemental analysis and nuclear magnetic resonance spectrometry. Statistical analysis showed that the data strongly correlated with seasonal climate and were divided in three groups corresponding to: (1) spring‐early summer, (2) summer and (3) autumn‐winter. The concentration of N, P, K and leaf ash content were highest in spring (recently formed leaves), reached the minimum during the hot and dry summer and increased slightly during the rainy period of autumn‐winter. Conversely, Na, Mg and Ca concentrations were lowest in spring‐early summer and increased during summer and autumn‐winter, the Ca concentration increasing five‐fold. Two cyclitol derivatives, quinic acid and quercitol were the major organic metabolites of the leaves. Their concentration along the season followed opposite trends. While quinic acid predominated during spring‐early summer, when it contributed 12% to the leaf osmotic potential, quercitol was predominant during autumn‐winter, when its contribution to leaf osmotic potential was about 10%. This different preponderance of the two compounds is expressed by the quercitol/quinic acid ratio, which can be as low as 0.2 in early summer and as high as 9 in winter. Sucrose and glucose concentrations also increased during autumn‐winter. Evidence for the quercitol protective role in plants during stress is discussed, and on the basis of structural similarity, it is suggested that quinic acid could have an identical importance, with a protective role against heat and high irradiance. It is concluded that the marked changes in Q. suber leaf composition throughout the year could have important implications in the plant capacity to endure climatic stress.     

Alicyclic acid metabolism in plants V. Biosynthesis of alicyclic acids from 14C-labeled glucose and erythrose in some plant tissues

Etiolated seedlings of Phaseolus mungo were fed with ¹⁴C-glucoseand the incorporation of ¹⁴C into shikimic and quinic acidswas determined. The incorporation of ¹⁴C into shikimic acidwas enhanced when non-labeled shikimic, quinic or 5-dehydroquinicacid was not significantly affected by these alicyclic acids.To examine whether the difference in biosynthetic patterns betweenshikimic and quinic acids is common in higher plants, flowersand leaves of several plants were fed with ¹⁴C-glucose or ¹⁴C-erythroseand the effciencies of these labeled sugars as precursors ofshikimic and quinic acids were compared. In seven of eight plantsamples, erythrose was superior to glucose as the precursorof shikimic acid, while there was no great difference in theefficiency of either sugar as the precursor of quinic acid.The possibility that the biosynthetic mechanism for quinic aciddiffers from that for shikimic acid is discussed. (Received September 12, 1973; )     

Evidence for two control genes regulating expression of the quinic acid utilization (qut) gene cluster in Aspergillus nidulans

The first three steps in quinic acid degradation in Aspergillus nidulans are catalysed by highly inducible enzymes encoded by a gene cluster regulated by an adjacent control region. Analysis of two non-inducible mutants has been done in diploid strains, where qutA8 is recessive and all three enzyme activities are fully induced in heterozygous qutA8/qutA+ diploids. In contrast, qutA4/qutA+ heterozygous diploids show semi-dominance of the mutant allele, giving markedly diminished growth on quinic acid and 30-40% decrease of enzyme induction. Strikingly, the qutA4/qutA8 heterozygous diploid grows to the same degree on quinic acid as the qutA4/qutA+ heterozygote and shows the same level of enzyme induction, whereas both the homozygous mutant diploids do not grow on quinic acid and show no enzyme induction. Therefore the two mutant genomes complement, identifying two distinct regulatory gene functions. A genetic model is proposed of a negatively acting gene (qutA) repressing expression of a positively acting gene (qutD, previously designated qutA8+) whose product is in turn required for expression of the three structural genes. The qutA4 mutation is interpreted to produce an altered repressor insensitive to quinic acid, and the qutD8 mutation the loss of activator protein. Close similarity in the regulation of the quinic acid gene cluster in Neurospora crassa suggests that the two types of control mutation, qalS and qalF, described for N. crassa may also reflect two regulatory genes.     

Species differences in the aromatization of quinic acid in vivo and the role of gut bacteria

1. The fate of (−)-quinic acid has been investigated in 22 species of animals including man. 2. In man and three species of Old World monkeys, i.e. rhesus monkey, baboon and green monkey, oral quinic acid was extensively aromatized (20–60%) and excreted in the urine as hippuric acid, which was determined fluorimetrically. 3. In three species of New World monkeys, i.e. squirrel monkey, spider monkey and capuchin, in three species of lemurs, i.e. bushbaby, slow loris and tree shrew, in the dog, cat, ferret, rabbit, rat, mouse, guinea pig, hamster, lemming, fruit bat, hedgehog and pigeon, oral quinic acid was not extensively aromatized (0–5%). 4. In the rhesus monkey, injected quinic acid was not aromatized, but largely excreted unchanged. 5. In rhesus monkeys pretreated with neomycin to suppress gut flora, the aromatization of oral quinic acid was considerably suppressed. 6. In rats and rhesus monkeys [¹⁴C]quinic acid was used and this confirmed its low aromatization in rats and its high aromatization in the monkeys. 7. Shikimic acid given orally was excreted as hippuric acid (26–56%) in rhesus monkeys, but not in rats. 8. The results support the view that quinic acid and shikimic acid are aromatized by the gut flora in man and the Old World monkeys.