A crude hydromethanolic extract from Pinus brutia bark and its fractions (diethyl ether, ethyl acetate, n-butanol, and aqueous fractions) were studied with regard to their phenolic content and antioxidant activities. The total phenolics and proanthocyanidins in each extract were quantified by spectrophotometric methods; the polyphenolic profile was analyzed by RP-HPLC-DAD-ESI-MS. All extracts were tested with regard to their ability to scavenge free radicals (ABTS radical cation, superoxide and hydroxyl radicals), reduce ferric ions, and inhibit 15-lipoxygenase. P. brutia bark extracts had high phenolic contents (303.79 -7.34-448.90 -1.39 mg/g). Except diethyl ether extract, all other extracts contained proanthocyanidins ranging from 225.79 -3.94 to 250.40 -1.44 mg/g. Several polyphenols were identified by RP-HPLC-DAD-ESI-MS: taxifolin in diethyl ether extract, a taxifolin-O-hexoside, catechin, procyanidin dimers, and trimers in ethyl acetate extract. Except diethyl ether extract, all other extracts were effective scavengers of superoxide and hydroxyl radicals (EC50 = 33.5 -1.1-54.93 -2.85 lg/mL and 0.47 -0.06-0.6 -0.0 mg/mL, respectively). All extracts had noticeable 15-lipoxygenase inhibitory effects (EC50 = 22.47 -0.75-34.43 -2.25 lg/mL). We conclude that P. brutia bark is very promising for the dietary supplements industry due to its high free radical scavenging and 15-lipoxygenase inhibitory effects.
A raw extract and four extractive fractions were obtained from Cedrus brevifolia (Cyprus cedar) bark. They were all studied regarding the phenolic content and profile using spectrophotometry and HPLC-DAD-ESI-MS. The antioxidant activity was investigated using in vitro assays: DPPH and ABTS radicals scavenging and reducing power assays. The ethyl acetate fraction had the highest total phenolic and proanthocyanidin contents; a taxifolin-O-hexoside, catechin, epicatechin and procyanidin oligomers (three dimers, two trimers) were identified in this fraction. The ethyl acetate fraction was found to possess the highest DPPH and ABTS radicals scavenging effects (EC50=13.9 ± 0.3 and 2.3 ± 0.0 μg/mL, respectively) and reducing capacity (EC50=9.1 ±0.1 μg/mL). Antioxidant effects were highly correlated with total phenolic and proanthocyanidin contents (r=0.89-0.99). These results suggest that Cedrus brevifolia bark is a new source of antioxidants.
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