Antioxidant Activity of a Flavonoid-Rich Extract of Hypericum perforatum L. in Vitro

Abstract

A flavonoid-rich extract of Hypericum perforatum L. (FEHP) was prepared by adsorption on macroporous resin and desorption by ethanol. Total flavonoid content of FEHP was determined by a colorimetric method. The major constituents of FEHP, including rutin, hyperoside, isoquercitrin, avicularin, quercitrin, and quercetin, were determined by HPLC analysis and confirmed by LC-MS. Different antioxidant assays were utilized to evaluate free radical scavenging activity and antioxidant activity of FEHP. FEHP was an effective scavenger in quenching DPPH and superoxide radical with IC50 of 10.63 microg/mL and 54.3 microg/mL, respectively. A linear correlation between concentration of FEHP and reducing power was observed with a coefficient of r2 = 0.9991. Addition of 150 microg of FEHP obviously decreased the peroxidation of linoleic acid during 84 h incubation, but the amount of FEHP over 150 microg did not show statistically significant inhibitory effect of peroxidation of linoliec acid (p > 0.05). FEHP exhibited inhibitory effect of peroxidation of liposome induced both by hydroxyl radical generated with iron-ascorbic acid system and peroxyl radical and showed prominent inhibitory effect of deoxyribose degradation in a concentration-dependent manner in site-specific assay but poor effect in non-site-specific assay, which suggested that chelation of metal ion was the main antioxidant action. According to the results obtained in the present study, the antioxidant mechanism of FEHP might be attributed to its free radical scavenging activity, metal-chelation activity, and reactive oxygen quenching activity.

In vitro free radical scavenging and DNA damage protective property of Coriandrum sativum L. leaves extract

“…Estimation of total flavonoid content Total flavonoid content was determined as described by Zou et al (2004). 0.25 ml of various extracts was diluted with 1.25 ml of distilled water.…”

Antioxidative and Hepatoprotective Effects ofPhysalis peruvianaExtract against Acetaminophen-Induced Liver Injury in Rats

“…The total flavonoid and phenol contents of PPWE was determined by colorimetric and Folin-Ciocalteu methods as described by Zou et al (2004) and Cliffe et al (1994), respectively. High performance liquid chromatographic method coupled with a photodiode array detector was established to analyze the selected flavonoid and phenolic components according to methods described by Glowniak et al (1996) and Wang et al (2003).…”

Antioxidant compounds from ethanol extracts of bamboo (Neosinocalamus affinis) leaves

“…Vitamin C was used as a positive control. Superoxide anionscavenging assay was performed according to the NADH-PMS-NBT (nicotinamide adenine dinucleotide (reduced form)-phenazine methosulfate-nitroblue tetrazolium chloride) method with luteolin as the positive control [23]. The detailed procedures of these experiments were described in our article reported before [24].…”