Regulation of the phenolic profile of berries can increase their antioxidant activity

The changes of the antioxidant activities (AOA), antiradical activities (ARA), low-density lipoprotein (LDL) oxidation, and total contents of phenolics, anthocyanins, flavonols, hydroxybenzoic acids, and hydroxycinnamic acids in black currant and black chokeberry, after treatment with ornithine decarboxylase inhibitor, a polyamine inhibitor (O-phosphoethanolamine, KF), and a phenol biosynthesis stimulator (carboxymethyl chitin glucan, CCHG), were analyzed spectrophotometrically. Gallic acid, hydroxycinnamic acids, and selected flavonol contents was analyzed by RP-HPLC. Both regulators increased the AOA measured as inhibition of peroxidation (IP) in black chokeberry, 1.71-fold after treatment with KF(1) and 1.74-fold after treatment with CCHG. In black currant IP was elevated after CCHG application only in lower dose (CCHG(1) 63.36% vs control 53.23%). In black chokeberry the total phenolics content was elevated 1.49-fold after KF(1) application and 1.31-fold after CCHG(2) application. The regulators had the lower effect on the phenolic accumulation in black currant. There was a strong relationship between the total phenolics in the both crops and anthocyanins, hydroxybenzoic acids, and hydroxycinnamic acids contents, respectively. Both regulators significantly changed the ratio of conjugated (rutin) to free (quercetin) flavonol mainly in black chokeberry. The antioxidant activities compared using LDL in vitro oxidation assay were increased more expressively after treatment with KF(2) in both crops.

Antioxidant capacity changes and phenolic profile of Echinacea purpurea, nettle (Urtica dioica L.), and dandelion (Taraxacum officinale) after application of polyamine and phenolic biosynthesis regulators

The changes of the antioxidant (AOA) and antiradical activities (ARA) and the total contents of phenolics, anthocyanins, flavonols, and hydroxybenzoic acid in roots and different aerial sections of Echinacea purpurea, nettle, and dandelion, after treatment with ornithine decarboxylase inhibitor, a polyamine inhibitor (O-phosphoethanolamine, KF), and a phenol biosynthesis stimulator (carboxymethyl chitin glucan, CCHG) were analyzed spectrophotometrically; hydroxycinnamic acids content was analyzed by RP-HPLC with UV detection. Both regulators increased the AOA measured as inhibition of peroxidation (IP) in all herb sections, with the exception of Echinacea stems after treatment with KF. In root tissues IP was dramatically elevated mainly after CCHG application: 8.5-fold in Echinacea, 4.14-fold in nettle, and 2.08-fold in dandelion. ARA decrease of Echinacea leaves treated with regulators was in direct relation only with cichoric acid and caftaric acid contents. Both regulators uphold the formation of cinnamic acid conjugates, the most expressive being that of cichoric acid after treatment with CCHG in Echinacea roots from 2.71 to 20.92 mg g(-1). There was a strong relationship between increase of the total phenolics in all sections of Echinacea, as well as in the studied sections of dandelion, and the anthocyanin content.