Naturally‐occurring antioxidants in leaf lipids

Abstract

Lipids have been extracted from the leaves of ryegrass, broad beans and lucerne, and shown to have marked antioxidant properties as stabilisers when added to lard. The effect is due in part to natural phenolic antioxidants extracted from leaves in the lipid fraction. A series of phenolic and polyphenolic compounds have been identified and quantified in leaf lipid extract. The main ones, common to all three species, are tocopherols, ferulic acid, and quercetin. Studies of antioxidant effects in model systems have shown, on the basis of peroxide values and oxygen-absorption induction periods, that quercetin (3 : 5 : 7: 3': 4'-pentahydroxy-flavone) is by far the most effective of these. It is, however, less effective under the test conditions than the artificial antioxidants BHA, BHT and propyl gallate.

Antioxidant activity of almonds and their by‐products in food model systems

“…However, the -CH=CH-moiety contributes to the radical stabilization of these acids through resonance, which has a positive influence on their overall antioxidant efficacy (34). Ferulic acid has been reported to exhibit a lower antioxidant activity than caffeic acid (35), possibly due to its methoxylation in the ortho position, which could possibly result in a decrease in its radical-scavenging or transition metal-chelating ability. Hydroxylation, as in caffeic acid, in place of methoxylation has been shown to be more effective in certain cases (36,37).…”

Protective effect of caffeic acid against beta-amyloid-induced neurotoxicity by the inhibition of calcium influx and tau phosphorylation

“…Caffeic acid [3-(3,4-dihydroxyphenyl)-2-propenoic acid] is a phenolic acid found in various agricultural products such as coffee beans, potatoes, grains, and vegetables (Friedman 1997;Hudson and Mahgoub, 1980;Ky et al, 1997). It is absorbed by the intestine through an active transport system after oral administration (Konishi et al, 2005), and then it acts as an antioxidant, anti-inflammatory, anti- Life Sciences 84 (2009) 257-262 tumor, and anti-metastatic agents (Chung et al, 2004;Koshihara et al, 1984;Tanaka et al, 1993).…”

Stabilization of Marine Oils With Flavonoids

“…Flavonoids occurring naturally in plants have been widely investigated in recent years because of their potential antioxidant activity which improves the stability of lipid-containing foods and their possible beneficial effects on human health (Herman 1976;Hudson and Mahgoub 1980;Das and Pereira 1990;Wanasundara and Shahidi 1994;Roedig-Penman and Gordon 1998). The relationship between chemical structure of flavonoids and their antioxidant activity in vegetable oils and various model systems has been thoroughly investigated (Hudson and Lewis 1983).…”