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PubMed1998

EPR detection of phytophenoxyl radicals stabilized by zinc ions: evidence for the redox coupling of plant phenolics with ascorbate in the H2O2-peroxidase system.

Chlorogenic acid (CGA; 3-o-caffeoylquinic acid), a phenylpropanoid metabolite of plants, was oxidized by H2O2 in the presence of horseradish peroxidase. The primary and secondary oxidized products both were free radicals which gave EPR multiline signals at g = 2.0044 and 2.0042 in the presence of zinc as a spin stabilizing agent. The EPR kinetics showed that ascorbate functioned as a cooperative reductant by regenerating CGA from its corresponding radicals. These results provide evidence to support the idea that the ascorbate-phenolic redox couple in conjunction with guaiacol peroxidase is an efficient H2O2 scavenging mechanism in higher plants.

Ascorbic Acid↗

PubMed2002

Induction of antioxidant flavonol biosynthesis in fresh-cut potatoes. Effect of domestic cooking.

The effect of fresh-cutting and subsequent cold storage on phenolic compounds from five long-term-stored potato cultivars (Agria, Cara, Liseta, Monalisa, and Spunta) was studied. Fresh-cutting induced the biosynthesis of three flavonols, which were identified by HPLC-DAD-ESIMS as quercetin 3-rutinoside, quercetin 3-diglucoside, and quercetin 3-glucosylrutinoside. The flavonols were detected after a lag period of 3 days of cold storage. The content ranged from 6 to 14 mg/100 g of fresh weight depending on the cultivar after 6 days of storage. Chlorogenic acid as the main caffeic acid derivative and the amino acids tyrosine and tryptophan were also quantified. The effect of cold storage under light or in dark was studied with new-season-harvested Monalisa potatoes. The flavonol induction was higher in fresh-cut potatoes stored under light than in the dark. However, caffeic acid derivatives were not affected. Domestic cooking such as boiling, microwaving, and frying provoked a partial loss of the flavonols, which were retained in the range of 4-16 mg per serving (213 g). Steam-cooking resulted in the highest retention of caffeic acid derivatives and aromatic amino acids compared with the other cooking methods studied. This means that due to the large amount of potatoes consumed in the Western diet, fresh-cut potatoes can be a significant source of health-promoting phenolics.

Antioxidants↗

PubMed2004

In vitro and ex vivo antihydroxyl radical activity of green and roasted coffee.

The specific antiradical activity against the hydroxyl radical of the water soluble components in green and dark roasted Coffea arabica and Coffea robusta coffee samples, both in vitro by the chemical deoxiribose assay and ex vivo in a biological cellular system (IMR32 cells), were determined. All the tested coffee solutions showed remarkable antiradical activity. In the deoxiribose assay, all the tested solutions showed similar inhibitory activity (IA%) against the sugar degradation (IA values ranged from 45.2 to 46.9%). In the cell cultures, the survival increase (SI%) ranged from 197.0 to 394.0% with C. robusta roasted coffee being significantly more active than the other samples. The coffee solutions underwent dialysis (3500 Da cutoff membrane) to fraction their components. In both systems, the dialysates (MW < 3500 Da) either from green or roasted coffee, showed antiradical activity, while the only retentates (MW > 3500 Da) from the roasted coffee samples were active. The preparative gel-filtration chromatography of roasted coffee C. robusta dialysate gave three fractions active in the biological system, all containing chlorogenic acid derivatives. The most active fraction was found to be that containing the 5-O-caffeoilquinic acid, which shows a linear relation dose-response ranging from 0.02 to 0.10 mM. The results show that both green and roasted coffee possess antiradical activity, that their more active component is 5-O-caffeoyl-quinic acid, and moreover that roasting process induces high MW components (later Maillard reaction products, i.e., melanoidins), also possessing antiradical activity in coffee. These results could explain the neuroprotective effects found for coffee consumption in recent epidemiological studies.

Antioxidants↗

PubMed2006

Determination of pharmacologically active ingredients in sweet potato (Ipomoea batatas L.) by capillary electrophoresis with electrochemical detection.

Sweet potato (Ipomoea batatas L.), in which vitamin C, chlorogenic acid, caffeic acid, quercetin, and rutin are abundant, is one of the functional food products aimed at introducing human dietary ingredients that aid specific body functions in addition to being nutritious. A method based on capillary electrophoresis with electrochemical detection (CE-ED) to qualitatively and quantitatively determine the pharmacologically active ingredients in sweet potato has been developed by our group. The effects of working electrode potential, pH and concentration of running buffer, separation voltage, applied potential, and injection time on CE-ED were investigated. Under the optimum conditions, the analytes could be well-separated within 20 min at the separation voltage of 18 kV in a 60 mmol L(-1) Borax running buffer (pH 9.0). A good linear relationship was established between peak current and concentration of analytes over 2 orders of magnitude with detection limits (S/N = 3) ranging from 7.14 x 10(-7) to 2.88 x 10(-7) g mL(-1) for all target ingredients. The satisfactory results show that this method is very successful and effective for the analysis of real samples.

Buffers↗

PubMed2000

Stability and bioavailability of antioxidants in garland (Chrysanthemum coronarium L.).

The stability and bioavailability of the major antioxidants in garland (Chrysanthemum coronarium L.), chlorogenic acid, 3,5-dicaffeoylquinic acid and 4-succinyl-3,5-dicaffeoylquinic acid, were investigated together with caffeic acid. These compounds were stable in artificial digestive juice, but more than 90% of them disappeared from plasma within 30 min after intravenous injection into rats. When they were orally administered, only caffeic acid could be detected.

Administration, Oral↗

PubMed2006

[Isolation of the chemical constituents from Shuanghuanglian injection and their structural identification].

OBJECTIVE: To isolate and identify the chemical constituents of Shuanghuanglian injection. METHODS: Chromatography and spectral analysis were performed to isolate and identify the chemical constituents respectively. RESULTS AND CONCLUSION: Seven compounds were isolated from Shuanghuanglian injection, including chlorogenic acid (I), caffeic acid (II), chrysophanol (III), physcion (IV), rutin (V), baicalein (VI) and glucose (VII). The compounds III, IV, V and VII were isolated and identified in Shuanghuanglian injection for the first time.

Caffeic Acids↗

PubMed1984

Lipid-phenolic radical adducts as a plausible mechanism of "plant ageing" pigment formation.

Co-oxidation of chlorogenic acid, caffeic acid, aesculetin and lucigenin with linoleic acid and egg phosphatidyl choline leads to the formation of fluorescent polymer materials. The fluorescent products are more lipophylic, they have lower elution volumes on Sephadex LH-20 column than related phenols and they differ by their fluorescence and chromatographic properties considerably from polymer lipid peroxidation products. From the presence in the excitation fluorescence spectra of a band corresponding to the phenols it was concluded that the fluorophoric groups were similar in both cases. The data are discussed in terms of liquid phase peroxidation and the appearance of the fluorescent species are attributed to the production of molecular adducts as a result of lipid and phenoxyl radical recombination. The characteristics of products obtained are compared with properties of fluorescent "plant ageing" pigments accumulated in aged and damaged plant cells.

Acridines↗

PubMed2006

Effect of Ilex extracts and isolated compounds on peroxidase secretion of rat submandibulary glands.

Free radicals are involved in diverse disorders such as tumoral, central nervous system alterations, immunological and inflammatory pathologies. Peroxidase is an oral enzyme involved in the defense of the oral cavity. Ilex species such as Ilex paraguariensis St. Hil. and the commercial product made with it "Yerba Mate" are used traditionally as antirheumatics and for the treatment of gastrointestinal diseases among others and also as a beverage with nutritional and stimulant properties. The presence of polyphenolic derivatives and flavonoids in the aqueous extract has been determined by HPLC analysis. In this study, the activity of aqueous extracts of I. paraguariensis and "Yerba Mate" on peroxidase secretion in female rat submandibular glands was investigated. The contribution to this pharmacological activity by some major hydrocynnamic acid derivatives present in the crude extracts, such as chlorogenic acid and caffeic acid and the most abundant methylxanthine, caffeine, was also evaluated. Spectrophotometrical determination of peroxidase activity showed that both extracts produced a significant increase in both secreted peroxidase and total peroxidase activity, though "Yerba Mate" showed a higher activity (EC(50) "Yerba Mate": 148+/-10 microg/ml; EC(50)I. paraguariensis: 841+/-20 microg/ml). The HPLC/DAD analysis of the crude extracts was performed and chlorogenic acid, caffeic acid and caffeine were identified and quantified. The results (expressed as W/W percentage of dried material) were as follows: I. paraguariensis: chlorogenic acid: 2.80+/-0.30, caffeic acid: 0.023+/-0.004, caffeine: 1.06+/-0.06; "Yerba Mate": chlorogenic acid: 1.98+/-0.37; caffeic acid: 0.020+/-0.003, caffeine: 0.70+/-0.06. Caffeine and chlorogenic acid were proved to play an important role in the induction of peroxidase secretion induced by the extracts.

Animals↗

PubMed2006

Antioxidant properties of Teaw (Cratoxylum formosum Dyer) extract in soybean oil and emulsions.

The antioxidant activity of an extract from Teaw (Cratoxylum formosum Dyer) leaves was studied in soybean oil and soybean oil-in-water emulsions. Samples containing the extract or reference antioxidants including chlorogenic acid, which comprises 60% of the Teaw extract, were stored at 60 degrees C and analyzed periodically for peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) to allow both hydroperoxides and hydroperoxide degradation products to be monitored. Chlorogenic acid and the Teaw extract were more effective than alpha-tocopherol in inhibiting lipid oxidation in bulk oil but were less effective in an oil-in-water emulsion in accordance with the polar paradox. The PV/TBARS ratio for oil samples containing chlorogenic acid was higher than for alpha-tocopherol and BHT because chlorogenic acid inhibits both hydroperoxide formation by radical scavenging and hydroperoxide decomposition by metal chelation. The importance of the metal-chelating activity in retarding hydroperoxide decomposition was confirmed by studying the decomposition of oil samples containing added ferric ions. The PV/TBARS ratio was higher for citric acid than for alpha-tocopherol in the presence of added ferric chloride, but the order was reversed in samples lacking ferric chloride. Samples containing added chlorogenic acid gave the highest PV/TBARS ratios both in the presence and absence of ferric ions. The PV/TBARS ratios for the samples containing antioxidants fell rapidly to lower values in a soybean oil-in-water emulsion than in the soybean oil. This was due to increased hydroperoxide decomposition in the emulsion at the same PV. The Teaw extract contained 12% oil-soluble components, which contributed to a slightly higher oil-water partition coefficient than that of chlorogenic acid. The antioxidant activity of the aqueous phase of the Teaw extract was reduced more than that of chlorogenic acid by partitioning of the oil-soluble components into oil, which showed that the less-polar components contributed to the antioxidant activity of the Teaw extract in aqueous media.

Antioxidants↗

PubMed2002

[Effects of NaCl stress on seedling growth and IAA metabolism of sweet potato and its relation to salt-tolerance].

Seedlings of three sweet-potato (Ipomoea batatas) cultivars with different salt-tolerance were stressed with different concentrations of NaCl during the seedling stage. Plant growth, leaf area growth, and IAA content decreased with increasing NaCl concentration, while the activities of POD and IAA oxidase increased. The extent of plant growth, leaf area growth and IAA content decrease and the extent of POD and IAA oxidase activity increase were larger in sensitive cultivar than those in moderately tolerant and tolerant cultivars. In addition, the content of chlorogenic acid increased under NaCl stress. Chlorogenic acid content reached its peak value at 170 mmol.L-1 of NaCl in sensitive and moderately tolerant cultivars and 225 mmol.L-1 of NaCl in tolerant cultivar. Chlorogenic acid content decreased with increasing NaCl concentration, but it was higher than that of the control.

Chlorogenic Acid↗

PubMed2006

[Study on the method of rapid quality control of aqueous solution of flos lonicerae japonicae extraction in the preparation of qingkailing injection].

To establish a rapid and accurate on-line quality control method for aqueous solution of Flos Lonicerae Japonicae extraction (ASFLJE) in the preparation of Qingkailing injection, the wavelength of UV original spectrum and its first derivative spectrum of ASFLJE were scanned. The most suitable spectrum type and wavelength correlated with the chlorogenic acid content in ASFLJE determined by RP-HPLC were chosen to build a regress model. The UV equation for predicting chlorogenic acid content in ASFLJE was established. Other 10 batches of ASFLJE were used for testing the on-line prediction results by comparison of the values of chlorogenic acid content determined by HPLC and predicting equation respectively. The most suitable wavelengths correlated with chlorogenic acid content were 294 nm (r = 0.991 9, n = 28) in the original UV spectrum and 316 nm (r = 0.995 9, n = 28) in the first derivative spectrum respectively. The predicting equation of chlorogenic acid content was: c(mg x mL(-1)) = 506. 254 3 x A316 nm + 0.177 1 (r = 0.995 9, n = 28). This predicting equation is credible and accurate, as tested by HPLC method (r = 0.991 5, n = 10). The prediction results of chlorogenic acid content were: the chlorogenic acid content in probable 90 percent ASFLJE was: 0.4-4.0(mg x mL(-1)). This method is rapid, simple and accurate, and can be used for the on-line quality control of ASFLJE in Qingkailing injection preparation.

Chlorogenic Acid↗

PubMed1973

Purification and some properties of two polyphenol oxidases from bartlett pears.

Two polyphenol oxidases (enzymes A and B) from Bartlett pear (Pyrus communis) peelings were purified to electrophoretic homogeneity according to polyacrylamide gel by a combination of Sephadex gel filtration, diethylaminoethyl cellulose chromatography and hydroxyl apatite chromatography. While the two enzymes differ electrophoretically at pH 9.3, chromatographically on hydroxyl apatite, and in the effect of ionic strength on activity, they are similar with respect to chromatography on diethylaminoethyl cellulose, substrate specificity, pH activity relations, inhibition by p-coumaric and benzoic acids, and heat stability. The two enzymes are o-diphenol oxidases with no detectable monophenolase or laccase activities. Pyrocatechol, 4-methyl catechol, chlorogenic acid, and d-catechin are good substrates of the enzymes with K(m) values in the range of 2 to 20 mm. Dependences of activity on oxygen and chlorogenic acid concentrations indicate a sequential mechanism for binding of these substrates to enzyme B. V(max) and K(m) values for oxygen and chlorogenic acid were 103 mumoles O(2) uptake per minute per milligram of enzyme, 0.11 mm and 7.2 mm, respectively, for enzyme B at pH 4.0. Both enzymes had maximum activity at pH 4.0 on chlorogenic acid. K(m) values for chlorogenic acid were independent of pH from 3 to 7; the V(max) values for both enzymes gave bell-shaped curves as a function of pH. p-Coumaric acid is a simple, linear noncompetitive inhibitor with respect to chlorogenic acid at pH 6.2 with K(i) values of 0.38 and 0.50 mm for enzymes A and B, respectively. Benzoic acid is a linear competitive inhibitor with respect to chlorogenic acid at pH 4.0 with K(i) values of 0.04 and 0.11 mm for enzymes A and B, respectively.

Journal Article↗

PubMed2000

A reevaluation of the peroxynitrite scavenging activity of some dietary phenolics.

Peroxynitrite is implicated in many diseases. Hence, there is considerable interest in potential therapeutic peroxynitrite scavengers. Diet-derived phenolics have been claimed to be powerful peroxynitrite scavengers. However, the reactivity of peroxynitrite can be significantly modified by bicarbonate and this has not been considered in evaluations of the scavenging activity of phenols. Bicarbonate (25 mM) significantly decreased the ability of several phenolic compounds (caffeic acid, o- and p-coumaric acid, gallic acid, ferulic acid) but not others (catechin and epicatechin) to inhibit peroxynitrite-mediated tyrosine nitration. Bicarbonate (25 mM) also decreased the ability of catechin, epicatechin, quercetin and ferulic acid but not chlorogenic acid, gallic acid, caffeic acid and o-coumaric acid to inhibit peroxynitrite-mediated alpha(1)-antiproteinase inactivation. These results show that physiological concentrations of bicarbonate substantially modify the ability of dietary phenolics to prevent peroxynitrite-mediated reactions. When assessing compounds for peroxynitrite scavenging, experiments should be conducted in the presence of bicarbonate to avoid misleading results.

Bicarbonates↗

PubMed1997

Prooxidant activity of caffeic acid, dietary non-flavonoid phenolic acid, on Cu2+-induced low density lipoprotein oxidation.

The effects of caffeic acid (CA) and chlorogenic acid (CHA), an ester of caffeic acid with quinic acid, were studied on isolated human Cu2+-induced low density lipoprotein (LDL) oxidation in initiation and propagation phases by measuring the formation of thiobarbituric acid reactive substances (TBARS), detecting conjugated diene and investigating the electrophoretic mobility change of LDL. Both non-flavonoids exhibited prooxidant and antioxidant activities depending on the LDL oxidation phases. CA and CHA (0.1 microM or more) enhanced LDL oxidation in the propagation phase. In agreement with previous findings, 0.5 microM CA and CHA inhibited LDL oxidation in the initiation phase. When 0.5 microM CA was added at 0 min, the duration of inhibition was about 60 min. Yet, after >9 min incubation with Cu2+, 0.5 microM CA accelerated LDL oxidation. The acceleration ratios were modified depending on the oxidation process and the concentration of added CA in the propagation phase. The maximum acceleration ratio was about 5 on addition of 2-5 microM CA, attained after 40 min incubation with Cu2+. Even in the propagation phase, an elevated concentration of CA inhibited oxidation; after 20 min incubation with Cu2+, CA at >3 microM functioned as an inhibitor. Further studies must be performed in order to clarify the counteracting deleterious prooxidant conditions of these widespread natural dietary compounds.

Antioxidants↗

PubMed2006

Inhibitory effect of green coffee bean extract on fat accumulation and body weight gain in mice.

BACKGROUND: An epidemiological study conducted in Italy indicated that coffee has the greatest antioxidant capacity among the commonly consumed beverages. Green coffee bean is rich in chlorogenic acid and its related compounds. The effect of green coffee bean extract (GCBE) on fat accumulation and body weight in mice was assessed with the objective of investigating the effect of GCBE on mild obesity. METHODS: Male ddy mice were fed a standard diet containing GCBE and its principal constituents, namely, caffeine and chlorogenic acid, for 14 days. Further, hepatic triglyceride (TG) level was also investigated after consecutive administration (13 days) of GCBE and its constituents. To examine the effect of GCBE and its constituents on fat absorption, serum TG changes were evaluated in olive oil-loaded mice. In addition, to investigate the effect on hepatic TG metabolism, carnitine palmitoyltransferase (CPT) activity in mice was evaluated after consecutive ingestion (6 days) of GCBE and its constituents (caffeine, chlorogenic acid, neochlorogenic acid and feruloylquinic acid mixture). RESULTS: It was found that 0.5% and 1% GCBE reduced visceral fat content and body weight. Caffeine and chlorogenic acid showed a tendency to reduce visceral fat and body weight. Oral administration of GCBE (100 and 200 mg/kg. day) for 13 days showed a tendency to reduce hepatic TG in mice. In the same model, chlorogenic acid (60 mg/kg. day) reduced hepatic TG level. In mice loaded with olive oil (5 mL/kg), GCBE (200 and 400 mg/kg) and caffeine (20 and 40 mg/kg) reduced serum TG level. GCBE (1%), neochlorogenic acid (0.028% and 0.055%) and feruloylquinic acid mixture (0.081%) significantly enhanced hepatic CPT activity in mice. However, neither caffeine nor chlorogenic acid alone was found to enhance CPT activity. CONCLUSION: These results suggest that GCBE is possibly effective against weight gain and fat accumulation by inhibition of fat absorption and activation of fat metabolism in the liver. Caffeine was found to be a suppressor of fat absorption, while chlorogenic acid was found to be partially involved in the suppressive effect of GCBE that resulted in the reduction of hepatic TG level. Phenolic compounds such as neochlorogenic acid and feruloylquinic acid mixture, except chlorogenic acid, can enhance hepatic CPT activity.

Adipose Tissue↗

PubMed2005

A chlorogenic acid-induced increase in GLP-1 production may mediate the impact of heavy coffee consumption on diabetes risk.

Recent prospective epidemiology links heavy coffee consumption to a substantial reduction in risk for type 2 diabetes. Yet there is no evidence that coffee improves insulin sensitivity and, at least in acute studies, caffeine has a negative impact in this regard. Thus, it is reasonable to suspect that coffee influences the risk for beta cell "failure" that precipitates diabetes in subjects who are already insulin resistant. Indeed, there is recent evidence that coffee increases production of the incretin hormone glucagon-like peptide-1 (GLP-1), possibly owing to an inhibitory effect of chlorogenic acid (CGA -- the chief polyphenol in coffee) on glucose absorption. GLP-1 acts on beta cells, via cAMP-dependent mechanisms, to promote the synthesis and activity of the transcription factor IDX-1, crucial for maintaining the responsiveness of beta cells to an increase in plasma glucose. Conversely, the "glucolipotoxicity" thought to initiate and sustain beta cell dysfunction in diabetics can suppress expression of this transcription factor. The increased production of GLP-1 associated with frequent coffee consumption could thus be expected to counteract the adverse impact of chronic free fatty acid overexposure on beta cell function in overweight insulin resistant subjects. CGA's putative impact on glucose absorption may reflect the ability of this compound to inhibit glucose-6-phosphate translocase 1, now known to play a role in intestinal glucose transport. Delayed glucose absorption may itself protect beta cells by limiting postprandial hyperglycemia -- though, owing to countervailing effects of caffeine on plasma glucose, and a paucity of relevant research studies, it is still unclear whether coffee ingestion blunts the postprandial rise in plasma glucose. More generally, diets high in "lente carbohydrate", or administration of nutraceuticals/pharmaceuticals which slow the absorption of dietary carbohydrate, should help preserve efficient beta cell function by boosting GLP-1 production, as well as by blunting the glucotoxic impact of postprandial hyperglycemia on beta cell function.

Chlorogenic Acid↗

PubMed2001

Model studies on reactions of plant phenols with whey proteins.

Whey proteins were modified by reaction with selected phenolic compounds (ferulic-, chlorogenic-, caffeic- and gallic acid) and related substances (quinic acid and p-quinone) as well as with extracts from coffee, tea, potato and pear at pH 9. The derivatives formed were characterized in terms of their physicochemical and digestion properties. The derivatization was accompanied by a reaction at the lysine and tryptophan side chains, whereby their content was decreased in comparison to that in the control whey proteins. Moreover, the solubility of the derivatives decreased over a broad pH range and the derivatization influenced the hydrophobe-hydrophile character of the whey proteins. The isoelectric points were shifted to lower pH values in the order of reactivity as follows: gallic acid > p-quinone > caffeic acid > chlorogenic acid. The other derivatives showed no or few changes compared to the control whey proteins. The formation of high molecular fractions was documented with SDS-PAGE. Especially the derivatives of chlorogenic-, caffeic-, gallic acid and p-quinone showed an increase in molecular weight of beta-lactoglobulin fraction from 18,300 to 20,000 Da. A dimer formation in molecular range 40,000 was also registered. MALDI-TOF-MS was applied to characterize the binding of the individual phenolic compounds or their oxidation products to the whey protein fractions, alpha-lactalbumin and beta-lactoglobulin. In vitro experiments showed that the digestion of the derivatized whey proteins with the enzymes of the gastrointestinal tract (trypsin, chymotrypsin, pepsin and pancreatin) was adversely effected. Similar results with regard to physicochemical characterization and digestion properties of the whey proteins treated with the applied extracts from plant beverages, fruit and vegetable were also documented. Coffee and tee were comparatively the most reactive extracts.

Electrophoresis, Polyacrylamide Gel↗

PubMed2002

Decreased Rubisco activity leads to dramatic changes of nitrate metabolism, amino acid metabolism and the levels of phenylpropanoids and nicotine in tobacco antisense RBCS transformants.

Tobacco transformants that express an antisense RBCS construct were used to investigate the consequences of a lesion in photosynthetic carbon metabolism for nitrogen metabolism and secondary metabolism. The results show that an inhibition of photosynthesis and decrease in sugar levels leads to a general inhibition of nitrogen metabolism, and dramatic changes in the levels of secondary metabolites. The response was particularly clear in plants that received excess nitrogen. In these conditions, a decrease of Rubisco activity led to an inhibition of nitrate reductase activity, accumulation of nitrate, a decrease of amino acid levels that was larger than the decrease of sugars, and a large decrease of chlorogenic acid and of nicotine, which are the major carbon- and nitrogen-rich secondary metabolites in tobacco leaves, respectively. Similar changes were seen when nitrogen-replete wild-type tobacco was grown in low light. The inhibition of nitrogen metabolism was partly masked when wild-type plants and antisense RBCS transformants were compared in marginal or in limiting nitrogen, because the lower growth rate of the transformants alleviated the nitrogen deficiency, leading to an increase of amino acids. In these conditions, chlorogenic acid always decreased but the decrease of nicotine was ameliorated or reversed. When the changes in internal pools are compared across all the genotypes and growth conditions, two conclusions emerge. First, decreased levels of primary metabolites lead to a dramatic decrease in the levels of secondary metabolites. Second, changes of the amino acid : sugar ratio are accompanied by changes of the nicotine:chlorogenic acid ratio.

Amino Acids↗