Cinnamic acid

About: Cinnamic acid is a research topic. Over the lifetime, 2960 publications have been published within this topic receiving 58312 citations. The topic is also known as: (E)-3-phenyl-2-propenoic acid & (2E)-3-phenyl-2-propenoic acid.

Inhibitory effects of curcumin on in vitro lipoxygenase and cyclooxygenase activities in mouse epidermis.

Abstract: Topical application of curcumin, the yellow pigment in turmeric and curry, strongly inhibited 12- O -tetradecanoylphorbol-13-acetate (TPA)-induced ornithine decarboxylase activity, DNA synthesis, and tumor promotion in mouse skin (Huang et al. , Cancer Res., 48: 5941–5946, 1988). Chlorogenic acid, caffeic acid, and ferulic acid (structurally related dietary compounds) were considerably less active. In the present study, topical application of curcumin markedly inhibited TPA- and arachidonic acid-induced epidermal inflammation (ear edema) in mice, but chlorogenic acid, caffeic acid, and ferulic acid were only weakly active or inactive. The in vitro addition of 3, 10, 30, or 100 µm curcumin to cytosol from homogenates of mouse epidermis inhibited the metabolism of arachidonic acid to 5-hydroxyeicosatetraenoic acid (5-HETE) by 40, 60, 66, or 83%, respectively, and the metabolism of arachidonic acid to 8-HETE was inhibited by 40, 51, 77, or 85%, respectively [IC 50 (concentration needed for 50% inhibition) = 5–10 µm]. Chlorogenic acid, caffeic acid, or ferulic acid (100 µm) inhibited the metabolism of arachidonic acid to 5-HETE by 36, 10, or 16%, respectively, and these hydroxylated cinnamic acid derivatives inhibited the metabolism of arachidonic acid to 8-HETE by 37, 20, or 10%, respectively (IC 50 > 100 µm). The metabolism of arachidonic acid to prostaglandin E 2 , prostaglandin F 2α , and prostaglandin D 2 by epidermal microsomes was inhibited approximately 50% by the in vitro addition of 5–10 µm curcumin. Chlorogenic acid, caffeic acid, and ferulic acid (100 µm) were inactive. In vitro rat brain protein kinase C activity was not affected by 50–200 µm curcumin, chlorogenic acid, caffeic acid, or ferulic acid. The inhibitory effects of curcumin, chlorogenic acid, caffeic acid, and ferulic acid on TPA-induced tumor promotion in mouse epidermis parallel their inhibitory effects on TPA-induced epidermal inflammation and epidermal lipoxygenase and cyclooxygenase activities.

Activity of phenylalanine ammonia-lyase (PAL) and concentrations of anthocyanins and phenolics in developing strawberry fruit

Abstract: Studies on regulation of production of phenolics in strawberry (Fragaria X ananassa Duch,) fruit were initiated by monitoring phenylalanine ammonia-lyase (PAL) activity and levels of anthocyanins, flavonoids, tannins, and other soluble phenols throughout fruit ontogeny in 'Tillikum'. PAL catalyzes the first step in the biosynthesis of phenylpropanoids, which are further modified into a wide variety of phenolic compounds. Peak in PAL activity (1 mol· s -l = 1 kat) of 90 pkat· mg -l protein was detected at 5 and 27 days after anthesis (DAA), when fruit was green and nearly ripe, respectively. PAL activity was only 10% of peak values in the white berry stage, when. fruit growth was most rapid. The second peak in PAL activity was followed by a rapid drop, to nearly zero in red-ripe fruit at 30 DAA. Total soluble phenols reached a maximum level soon after anthesis, just before the first peak in PAL activity, then declined to a low constant value well in advance of fruit ripening. Similar changes were observed in levels of tannins and flavonoids that, at anthesis, accounted for 44% and 51% of the soluble phenols, respectively. The concentration of anthocyanin was very low throughout most of fruit development, but beginning at 23 DAA it increased from 0.53 mg·g -l fresh weight in 3 days. This accumulation paralleled the second rise in PAL activity. Accordingly, strawberry fruit have a developmental- dependent expression of PAL activity and accumulation of phe- nolic substances derived from the phenylpropanoid pathway. Many distinctive developmental features of fleshy fruits, such as loss of astringency and appearance of characteristi c color at ripening, are related to changes in the synthesis and accumu- lation of phenolic compounds. For example, astringency is a tannin effect and the color of ripe fruit often results from ac- cumulated anthocyanins. Besides anthocyanins and condensed tannins (proanthocyanins), fruit also contain other flavonoids, as well as simple phenols such as phenolic acids and cinnamic acid derivatives (see review by Macheix et al., 1990). The type and amount of phenolic compounds in plant tissues depend on genotype and developmental stage (Hahlbrock and Griseback, 1-979). Tissues of fleshy fruits commonly have high levels of cinnamic acid derivatives, flavonoids, and tannins during early development, but accumulate anthocyanins only near maturity (Billet et al., 1978; Hyodo, 1971; Kataoka et al., 1983). In- formation on metabolism of phenolics is important not only because they influence the quality of fruit and related processed products, but also because of their roles in developmental phys- iology and defense mechanisms. Understanding phenolic metabolism in plant cells and tissues requires knowledge of the biosynthetic reactions and their reg- ulation. The majority of monophenolic compounds, most of which are phenolic acids and phenylpropanoids, are interme- diates and derivatives of the shikimate and phenylpropanoid pathways. Flavonoids, including anthocyanins and condensed tannins, are derived from p-coumaric acid of the phenylpropa- noid pathway. Another group of tannins, the hydrolyzable tan- nins, are ester derivatives of gallic acid that maybe synthesized via the shikimate or phenylpropanoid pathways (Ishikura et al., 1984). Conversion of L-phenylalanine to trans -cinnamic acid is the initial step of the phenylpropanoid pathway. This ammonia elimination reaction is catalyzed by L-phenylalanine ammonia- lyase (PAL) (EC 4.3.1.5), a key regulatory enzyme in the bio-

Benzoic and Cinnamic Acid Derivatives as Antioxidants: Structure−Activity Relation

Abstract: The antioxidant activity of four derivatives of benzoic acid was systematically compared with the activity of the four homologous derivatives of cinnamic acid. The couples of compounds differed for the kind of aromatic substitution (p-hydroxy, p-hydroxymethoxy, p-hydroxydimethoxy, dihydroxy). The antioxidant activity was measured using (i) a competition kinetic test, to measure the relative capacity to quench peroxyl radical and (ii) the in vitro oxidative modification of human low-density lipoprotein (LDL), initiated by 2,2'-azobis(amidinopropane) dihydrochloride or catalyzed by Cu(II). In both models, cinnamic acids were more efficient than their benzoic counterparts. As for the influence of the aromatic substitution, in the kinetic test the antioxidant activity increased in the sequence p-hydroxy < p-hydroxymethoxy < dihydroxy < p-hydroxydimethoxy. In contrast, in the LDL system, the dihydroxy acids had an antioxidant capacity equal to or higher than that of the p-hydroxydimethoxy acids.

Effects of Naturally Occurring Antioxidants on Peroxidase Activity of Vegetable Extracts

Abstract: The effectiveness of α-tocopherol, two flavonoids (quercetin and ru-tinic acid) and a cinnamic acid (chlorogenic acid) as inhibitors of peroxidase was evaluated. Four concentrations, 125, 250, 500 and 1000 mg%, of each compound were used. Crude extracts of tomatoes, carrots and eggplant were the sources of enzyme activity. Peroxidase activity of carrots and eggplant was inhibited more than that of tomato by all antioxidants. Alpha-tocopherol was least effective in all systems and at all concentrations. Chlorogenic acid was most effective, followed by quercetin and rutinic acid.

Cinnamon: A Multifaceted Medicinal Plant

Abstract: Cinnamon (Cinnamomum zeylanicum, and Cinnamon cassia), the eternal tree of tropical medicine, belongs to the Lauraceae family. Cinnamon is one of the most important spices used daily by people all over the world. Cinnamon primarily contains vital oils and other derivatives, such as cinnamaldehyde, cinnamic acid, and cinnamate. In addition to being an antioxidant, anti-inflammatory, antidiabetic, antimicrobial, anticancer, lipid-lowering, and cardiovascular-disease-lowering compound, cinnamon has also been reported to have activities against neurological disorders, such as Parkinson's and Alzheimer's diseases. This review illustrates the pharmacological prospective of cinnamon and its use in daily life.