Free radical scavenging and total phenolic contents from methanolic extracts of Ulmus davidiana

Comparison of antioxidant activity in wild plant (Adenophora triphylla) leaves and roots as a potential source of functional foods

Adenophora triphylla is commonly used in food materials and oriental medicine as an analgesic, anti-inflammatory, and antitussive. In the present study, the leaves and roots of A. triphylla were extracted with water and ethanol, respectively, to examine the extracts' in vitro antioxidant activities and total phenolic contents, as well as A. triphylla's potential as a new functional food source and safe and inexpensive supply of antioxidants. Different antioxidant tests were employed and the results were compared with ascorbic acid as a standard antioxidant. The total extractable contents of phenolic compounds and flavonoids, which relate to antioxidant activity in medicinal plants, were also measured. The leaf extracts had notable levels of total phenolics and flavonoids and showed high radical and nitrite scavenging activities as well as inhibition activity against enzymes that induce oxidation. These results suggest that A. triphylla leaves are a potential ingredient for food supplements and a natural source of antioxidants.

Free radical-scavenging activity and flavonoid contents of Polygonum orientale leaf, stem, and seed extracts

The present study was designed to explore the total flavonoid and taxifolin contents and the radical-scavenging activity of 50% ethanol extracts of Polygonum orientale leaves, stems, and seeds by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The extract with higher total flavonoid content has higher radical scavenging activity. Taxifolin (IC50 = 2.83 ?mol/L) has antioxidant activity stronger than that of rutin (IC50 = 3.08 ?mol/L). The free radical-scavenging potentials of chloroform, ethyl acetate, water, ethanol, and methanol extracts of Polygonum orientale seeds were also investigated. The free radical-scavenging abilities of various extracts were determined as: methanol > ethanol > water > ethyl acetate > chloroform. <br><br><font color="red"><b> This article has been retracted. Link to the retraction <u><a href="http://dx.doi.org/10.2298/ABS181226060E">10.2298/ABS181226060E</a><u></b></font>

Antioxidant effects of phlorotannins isolated from Ishige okamurae in free radical mediated oxidative systems

Three phlorotannins, including phloroglucinol, diphlorethohydroxycarmalol, and 6,6'-bieckol, were isolated from Ishige okamurae by column chromatography. The structures of the phlorotannins were determined on the basis of spectroscopic analysis, including NMR and mass spectrometry (MS) techniques. Antioxidant effects of phlorotannins were measured by direct free radical scavenging activities using the electron spin resonance spectrometry (ESR) technique and cellular systems in vitro. The results indicated that diphlorethohydroxycarmalol and 6,6'-bieckol showed potential radical scavenging activities against the 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl, alkyl, and superoxide radicals. Moreover, no cytotoxicities of the phlorotannins on human fetal lung fibroblasts cell line (MRC-5), mouse macrophages cell line (RAW264.7), and human leukemic cell line (HL-60) were observed. In addition, diphlorethohydroxycarmalol and 6,6'-bieckol significantly reduced the intracellular reactive oxygen species level assessed by 2',7'-dichlorofluorescein diacetate (DCFH-DA) assay in RAW264.7 cells, and myeloperoxide (MPO) activity in HL-60 cells and radical-mediated oxidation of cell membrane proteins in RAW264.7 cells were dose-dependently inhibited in the presence of diphlorethohydroxycarmalol and 6,6'-bieckol. In conclusion, these results suggested that phlorotannins could be used as novel functional foodstuffs or antioxidants in the cosmetic and drug industries.