We used the Dpph method to assess in vitro the antiradical activity of extracts from the roots, leaves and fruits of six Rumex L. (dock) species. Data from preliminary screening indicated that all the tested extracts showed antioxidant properties. The degree of antiradical activity depended upon the plant part. Fruit extracts from R. hydrolapathum Huds., R. obtusifolius L. and R. confertus Willd. showed stronger antiradical properties than the other tested material. We also determined tannin content levels in the extracts and their correlation with antioxidant activity.
The chemical composition and bioactivity of a water/methanol extract prepared from aerial parts of Circaea lutetiana were determined. HPLC-DAD-MS3 analysis revealed the presence of 14 different compounds comprising phenolic acids, ellagitannins and flavonoids. Antioxidant assays showed the extract's strong scavenging activity towards DPPH (SC50 33.1±3.1 μg/ml), O2 - (SC50 4.0±2.3 μg/ml) and H2O2 (SC50 below 2 μg/ml). Enzyme-based studies revealed that Circaea lutetiana extract inhibits the activity of hyaluronidase (IC50 13.3±2.4 μg/ml) and lipoxygenase (IC50 44.7±1.4 μg/ml). These results support some traditional uses of Circaea lutetiana.
Hylocereus undatus flower is commonly used as food or for medicinal purposes in south China. To study its antioxidant activity and mechanism we used antioxidant and chemical assays to compare two commercial samples from different locations (Shenjing, Qixing). The difference in antioxidant levels corresponded with differences in chemical content (including total phenolics, total flavonoids, kaempferol and quercetin) between Shenjing and Qixing. The antioxidant ability of H. undatus flower seems attributable to total phenolics (mainly total flavonoids). Kaempferol is one of the main bioactive components. H. undatus flower exerts its antioxidant effects through metal chelation and radical scavenging via hydrogen atom (H•) and electron (e) donation.
We used DPPH scavenging assays to study the antioxidant activity of three native Polish species of blackberry leaves (Rubus kuleszae Ziel., R. fabrimontanus (Sprib.) Sprib. and R. capitulatus Utsch.). All the studied extracts (methanolic, water, methanolic-water) showed high DPPH free radical scavenging activity (IC50 450.0-186.0 μg/ml). The most effective of the studied species was Rubus kuleszae. Total content of phenolic compounds (70.50-136.04 mg GAE/g) and phenolic acids (14.70-38.26 mg CAE/g) was determined spectrophotometrically. Antioxidant activity correlated positively with total content of phenolic compounds and phenolic acids.