Phenol biosynthesis in higher plants. Gallic acid.

The effect of SA on the regulation of plant growth has been considered significant for a long time (Raskin, 1992, 1995; Çanakci, 2003; Pancheva ., 1996). Present results show that dose-response correlation of ASA, which is known to hydrolyze to SA in aqueous solutions (Mitchell and Broadhead, 1967), is clear: lower doses encourage growth, while higher doses inhibit it. These effects are marked on hypocotyl and root growth. The inhibitive effect observed in high concentrations can be attributed to toxic stress, but we do not know by which mechanism the stimulating effect can be explained. This may be associated with the (oxine-like) regulatory effect of SA on cell growth and division (Kling and Meyer, 1983). Similarly, the decreases in chlorophyll amounts in high ASA concentrations may be attributed to the toxic effect. This decrease caused by acetylsalicylic acid in chlorophyll amount was claimed to be a result of the prevention of chlorophyll biosynthesis or acceleration of chlorophyll destruction or both (Yang ., 2002). These issues can be clarified only through further studies.

An Improved Synthesis of Mescaline from Gallic Acid - …

Synthesis of gallic and shikimic acids in plants

Gallic acid (anhydrous) for synthesis

N2 - 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 α-hydroxycarbonyl and oxidation of the resulting enediol. 3-Dehydroshikimate enolization in water was catalyzed by inorganic phosphate while Zn2+ was used to catalyze enolization in acetic acid. Enediol oxidation employed Cu2+ 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 CuSO4. 3-Dehydroshikimate-containing, phosphate-buffered culture supernatants reacted with stoichiometric amounts of CuCO3Cu(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 O2 and a catalytic amount of Cu(OAc)2.

Synthesis of gallic acid (‐14COOH) | Request PDF

AB - 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 α-hydroxycarbonyl and oxidation of the resulting enediol. 3-Dehydroshikimate enolization in water was catalyzed by inorganic phosphate while Zn2+ was used to catalyze enolization in acetic acid. Enediol oxidation employed Cu2+ 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 CuSO4. 3-Dehydroshikimate-containing, phosphate-buffered culture supernatants reacted with stoichiometric amounts of CuCO3Cu(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 O2 and a catalytic amount of Cu(OAc)2.

“Epoxy resin from gallic acid,” BioResources 13(1), 632-645

The literature about the effects of SA and ASA on germination in plants is limited. It was reported in a study conducted on varieties of tomatoes ( L.) using different concentrations of various (benzoic acid, chlorogenic acid, ferulic acid, p-hydroxybenzoic acid, salicylic acid and 2,4-diacetyl phloroglucinol) that strong phytotoxic effects were observed in 10 μM concentration of chlorogenic acid, in particular. It was stated in the same study that high concentrations of (100 and 1000 μM) prevented germination, reduced root and shoot fresh weight, while lower concentrations did not produce a significant difference in comparison to controls, but brought about different effects when compared to one another. Only 1 μM concentration of 2,4-diacetyl phloroglucinol (phl) increased fresh weight significantly, relative to the control (Jung ., 2001). In a study exploring the effects of short- and long-term SA exposure on germination of cabbage (L.), tomat L.) and cucumber (L.) seeds, it was seen that long-term applications were more effective than short-term applications in preventing germination (K’Opondo ., 2001). It was reported that high concentrations of ferulic acid had a higher inhibitive effect, than lower concentrations, on germination of soy bean ( L. Merill) seeds and led to formation of dwarf roots with necrotic appearance (Colpas ., 2003). It was established that high concentrations of various , prevented seed germination of . Inhibition of germination by exogenous applications of all highly active phenols (10-2 M) except salicylic acid was alleviated by the application of gibberellic acid and kinetin (Khan and Ungar, 1986). Coumarin application was seen to prevent germination in , particularly in high concentrations and encouraged root formation in lower concentrations (Yamamoto and Fujii, 1997). It was established that high concentrations of various (ferulic, gallic, p-hydroxybenzoic acid and p-vanillin) prevented seed germination of six different types of wild herbs. Lower concentrations of these compounds, on the other hand, were seen either to remain ineffective or to show a stimulator effect (Regiosa ., 2004).

ENZYMATIC SYNTHESIS OF GALLIC ACID ESTERS - …

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 α-hydroxycarbonyl and oxidation of the resulting enediol. 3-Dehydroshikimate enolization in water was catalyzed by inorganic phosphate while Zn2+ was used to catalyze enolization in acetic acid. Enediol oxidation employed Cu2+ 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 CuSO4. 3-Dehydroshikimate-containing, phosphate-buffered culture supernatants reacted with stoichiometric amounts of CuCO3Cu(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 O2 and a catalytic amount of Cu(OAc)2.

Phenol biosynthesis in higher plants

There is no sufficient information available as to how ASA influences weight change in plants or what effects it shows on their pigment and protein contents depending on concentrations. It was reported in a study by Shettel and Blake (1983) that SA and p-hydroxybenzoic acid application prevented growth of seedling and reduced dry weight increase in corn (L.), soy bean ( L.), oat (L.) and three wild plants. It was observed in barley plants germinated and grown in different salicylic acid concentrations that secondary leaf area increase and root development were prevented, while protein and chlorophyll (a+b) amount decreased parallel to concentration increase (Pancheva ., 1996). High concentrations of ASA were reported to inhibit root and coleoptile growth (Larque-Saavedra, 1978). In a study carried out with disks taken from primary leaves of one-week bean seedlings, chlorophyll a and b amount decreased parallel to the increase in ASA concentration, while carotenoid amount remained unchanged, but fresh weight loss and protein destruction increased (Çanakci, 2003). The fact that the effects of salicylic acid on plants vary depending on the type of plant, life period during application, concentration applied, manner and duration of application makes it difficult to explain the physiological effects of SA. This situation can be clarified only through a high number of research studies. As it is known, seed germination is a complicated process which aims at the mobilization of reserve substances and thereby includes various resulting hormonal modifications, gene induction and a high number of enzyme syntheses. We think that it is important to know whether SA, a new plant hormone, has any effect on this process which starts with swelling. Therefore, in this study, effects of different concentrations of ASA on germination, various growth parameters and chlorophyll (a+b) amount of cucumber ( L. Beit Alpha) were examined.