Ferulic antioxidative activity

There are also more complex hydroxycinnamic acids in cereals and other members of the Poaceae. These are cell wall-bound mono-, di- and tri-ferulates. Although they appear to have significant antioxidant activity, their bioavailability (release from cell walls and subsequent absorption in humans) is very low. 

An HPLC method using a 90-min binary gradient with (a) acidified water, pH 2.4, and (b) acetonitrile on an Adsorbosphere C]8, 3-/zl cartridge (Alltech) was also developed for pheno-lics in barley (127). Seven phenolic compounds, including vanillic acid, p-coumaric acid, ferulic acid, and their derivatives, were separated by HPLC after alkaline hydrolysis in order to evaluate the role of bound phenolic acids in their antioxidant activity in beer. In this method, cis and trans isomers of p-coumaric and ferulic acids are quantified by HPLC, although cls-p-coumaric acid was not well separated from its trans isomer in this analysis. 

In addition to their direct antioxidant activity, ferulic acid and its ester derivatives have also been shown to act as indirect antioxidants, that is, to induce cytoprotective (phase 2) enzymes [Dinkova-Kostova et al., 1998 Dinkova-Kostova, 2002], Similarly to curumin, ferulic acid derivatives also... 

Sultana R, Ravagna A, Mohmmad-Abdul H, Calabrese V, Butterfield DA. 2005. Ferulic acid ethyl ester protects neurons against amyloid beta-peptide(l-42)-induced oxidative stress and neurotoxicity Relationship to antioxidant activity. J Neurochem 92 749-758. 

Nystrom, L. Makinen, M. Lampi, A. Piironen, V. 2005. Antioxidant activity of steryl ferulate extracts from rye and wheat bran. J. Agric. Food Chem. 53 2503-2510. 

Table 10.2 Antioxidant activities of steryl ferulates in various studies. 

Model system (Monitored factor representing oxidation) Substrate Temp, (if not ambient) Steryl ferulates evaluated (in the order of increasing antioxidant activity) Reference... 

STEROLS Phytosterols are mostly associated with unrefined vegetable oils and exist as derivatives of phenolic acids (e.g., ferulic acid). Several studies are available on antioxidant activity of sterols and their derivatives from sources such as corn fiber, oats, and rice. These compounds can be obtained from the unsa-ponifiable fraction that is removed during vegetable oil refining. Triterpene alcohols and hydrocarbons (131), or sterols (Figure 20) from oats (132, 133), rice (134, 135),... 

Phenolic acids include the benzoic acids (Ce-Ci), e.g., gallic, vanillic, syringic, protocatechuic, p-hydroxy-benzoic acid, as well as cinnamic acids (C6-C3), e.g., caffeic, p-coumaric, ferulic, sinapic acids, and their dep-sides and derivates, e.g., rosmarinic acid and lithospermic acid (Fig. 1). Phenolic acids and flavonoids in plants may occur in the free form, but they are often glycosylated with various sugars, especially glucose. Phenolic acids may also be present in the esterified as well as bound forms. Free phenolic acids are found especially in herbs and spices and, very often, in compounds responsible for antioxidant activity (benzoic and cinnamic acids and some of their derivatives). The bound forms are more common for the fruits, vegetables, and other plant materials. Therefore, in some cases, it is necessary to combine the analysis of their free and bound forms. 

Other phenolic compounds are in soybeans, mainly acids, such as chlorogenic, isochlorogenic, caffeic, ferulic, -coumaric, syringic, vanillic, -hydroxybenoic, salicylic, and sinapic acids. Some of these acids have strong antioxidant activity (White Xing, 1997). 

Ferulic acid (36) Antioxidant activity by extending the induction time of lipid oxidation in the Rancimat test 108... 

The phenolic compound content of the Cucurbitaceae is very low. Only trace amounts (3mg/ kg f w.) of neochlorogenic acid (3 -caffeoylquinic acid) were detected in one out of three zucchini (summer-squash) cultivars [40]. In an extensive study on the phenolic content of melons, watermelon, etc., only traces (ferulic acid were detected after hydrolysis. Very small antioxidant activity was reported for cucumber extracts [61], consistent with the very small phenolic compound content. However, the phenolic metabolism of melons is activated under environmental stress and wounding induces the phenylalanine ammonia lyase (PAL) gene [62]. 

Caffeic, p-coumaric, ferulic, and sinapic acids (Fig. 4) and their esters and glycosides have all shown interesting antioxidant activity [122 123]. 3,5-Dicaffeoyl-4-succinylquinic acid and 3,5-dicaffeoylquinic acid (isochlorogenic acid) showed antioxidant activity in a P-carotene-linoleate method [123]. 

When considering whole food, the hydrolysis method was another factor in antioxidant activity. In wheat bran, the alkaline hydrolysable fraction, mostly ferulic acids, had greater antioxidant activity as compared to the acid hydrolysable fractions [116]. 

Proteins have strong binding properties with flavonoid antioxidants in foods and biological systems, and generally increase the oxidative stability of liposomes. The addition of bovine serum albumin (BSA) increased the oxidative stability of a lecithin-liposome and changed the relative antioxidant activity of various pairs of flavonoids and phenolic acids (Table 10.13). In the absence of BSA, the activity of phenolic antioxidants decreased in the order ferulic acid > epicatechin > catechin > malvidin > caffeic acid quercetin > propyl gallate. In the presence of BSA, the activity of malvidin increased, followed by rutin and ferulic acid, but the activity of epicatechin and catechin decreased. 

Muggh, D.S., Burkoth, A.K., Keyser, S. A., Lee, H.R., Anseth, K.S., 1998. Reaction behavior of biodegradable, photo-cross-linkable polyanhydrides. Macromolecules 31, 4120—4125. Ouimet, M.A., Griffin, J., Carbone-Howell, A.L., Wu, W.-H., Stebbins, N.D., Di, R., Uhrich, K.E., 2013. Biodegradable ferulic acid-containing poly (anhydride-ester) degradation products with controlled release and sustained antioxidant activity. Biomacromolecules 14, 854—861. 

---