Antioxidant Properties of Polyphenolic Extracts from Quercus Laurina, Quercus Crassifolia, and Quercus Scytophylla Bark

Abstract

The objective of this work was to determine the concentration of total phenols, total flavonoids, hydroxycinnamic acids, and proanthocyanidins present in crude extracts of Quercus laurina, Q. crassifolia, and Q. scytophylla bark. They were extracted by ethanol (90%) maceration and hot water. The antioxidant capacity was determined by the ability to capture OH•, O2•−, ROO•, H2O2, NO•, and HClO. The hot water crude extract of Q. crassifolia was chosen to be concentrated and purified due to its higher extraction yield (20.04%), concentration of phenol compounds (747 mg gallic acid equivalent (GAE)/g, 25.4 mg quercetin equivalent (QE)/g, 235 mg ChAE/g, 25.7 mg chlorogenic acid equivalents (ChAE)/g), and antioxidant capacity (expressed as half maximal effective concentration (EC50, µg/mL): OH• = 918, O2•− = 80.5, ROO• = 577, H2O2 = 597, NO• ≥ 4000, HClO = 740). In a second stage, Q. crassifolia extracted with hot water was treated with ethyl acetate, concentrating the phenol compounds (860 mg GAE/g, 43.6 mg QE/g, 362 ChAE/g, 9.4 cyanidin chloride equivalents (CChE)/g) and improving the scavenging capacity (OH• = 467, O2•− = 58.1, ROO• = 716, H2O2 = 22.0, NO• ≥ 4000, HClO = 108). Q. crassifolia had the highest polyphenolic concentration and the better capacity for scavenging reactive species, being a favorable candidate to be considered in the development of new products.

Biological and Chemical Insights of Beech (Fagus sylvatica L.) Bark: A Source of Bioactive Compounds with Functional Properties

“…The strongest antioxidant activity is recorded for BBE2, where the strongest amount of phenols was recorded. Many bark extracts have been evaluated for their antioxidant capacities, commonly associated to their content of phenolic compounds [28,29,30]. Beech bark contains some of biologically active components, such as catechin, epicatechin, syringic acid, vanillic acid etc., indicating that the antioxidant activity of the extracts can be at least partially ascribed to these bio-components (Table 4).…”

Environmentally Friendly Methods for Flavonoid Extraction from Plant Material: Impact of Their Operating Conditions on Yield and Antioxidant Properties

“…Therefore, researchers have focused their work on improving the flavonoid recovery methods of some barks, especially when highly lignified barks are wasted from the forestry industry. Recent work has mentioned the extraction of flavonoids from the bark of Pinus radiata [ 24 ], chestnuts species [ 25 ], Caesalpinia ferrea C. [ 26 ], Pinus halepensis [ 27 ], Quercus laurina , Quercus crassifolia , and Quercus scytophylla [ 28 ].…”

Investigation of the Antibacterial Activity and Subacute Toxicity of a Quercus crassifolia Polyphenolic Bark Extract for its Potential Use in Functional Foods

“…The observed differences in the bacteria growth inhibition between QCBe and QCBae can be explained by dissimilarities in terms of their chemical composition. A previous study demonstrated that QCBe had a significantly higher content of total phenols, total flavonoids, and hydroxycinnamic acids than QCBae (Valencia-Avilés et al, 2018). The higher phenol content of the purified extract could influence its higher activity toward a gramnegative bacterium, such as E. coli.…”

“…In a previous work, it was determined that a purified extract from a Mexican oak ( Quercus crassifolia bark, QCBe) was a good source of polyphenols (860.39 ± 5.68 mg GAE/g). Additionally, this extract showed a higher free radical scavenging ability in vitro toward reactive species of biological importance (hydroxyl and peroxyl radical and the superoxide anion) than Oligopin®, a commercial polyphenolic extract widely used in nutraceutical products (Valencia‐Avilés et al., ).…”

“…Fifty grams of bark powder were mixed with 500 mL of water for extraction under reflux during 1 hr and subsequently washed with 500 mL of hot water to obtain the aqueous crude extract (QCBae), which was filtered, concentrated, and lyophilized. As demonstrated by a previous study, the ethyl acetate soluble fraction (QCBe) obtained from the QCBae contained a higher concentration of total phenols, total flavonoids, and hydroxycinnamic acids with a better antioxidant capacity compared to QCBae (Valencia-Avilés et al, 2018). The purification of the QCBae to yield QCBe was performed following the method described elsewhere (Diouf, Stevanovic, & Cloutier, 2009;Valencia-Avilés et al, 2018).…”