Screening of the antioxidant potentials of polar extracts from fruits of Eryngium planum and Eryngium amethystinum

The research shows the antioxidant potential of methanolic and methanolic-water extracts of two species Eryngium amethystinum and Eryngium planum using the β-carotene-linoleic acid assay. The fruits of both species were the source for preparing the samples. The antioxidant measurements were done by UV-VIS spectrophotometric using the phenomenon of bleaching of solution of β-carotene during its oxidation. The results are presented as AA50 value, which refers to the concentration of a substance needed to inhibit 50% oxidation of a sample and the standard activity coefficient (SAC), which corresponds to the amount of reference substance (trolox) to which it has the same potential like the tested substance.

Phenolic Contents and Antioxidant Potential ofCrataegusFruits Grown in Tunisia as Determined by DPPH, FRAP, andβ-Carotene/Linoleic Acid Assay

Crataegusfruit is one of most important fruits in Tunisian flora. Some fruits of this genus are edible. This study was undertaken in order to examine the benefits of these fruits in human health and their composition of antioxidants including total polyphenol, flavonoids, proanthocyanidins content, and total anthocyanins. The antioxidative properties of the ultrasonic methanolic extract were assessed by different in vitro methods such as the FRAP, DPPH, andβ-carotene/linoleic acid assay. We concluded that peel fraction of red fruits possessed relatively high antioxidant activity and might be a rich source of natural antioxidants in comparison with the pulp and seed fruit extract. The results also showed that hawthorn yellow fruit presents lower amounts of phenolic content, absence of anthocyanins, and less antioxidant capacity. Most of peel and seed fractions were stronger than the pulp fractions in antioxidant activity based on their DPPH IC50, FRAP values, and results ofβ-carotene/linoleic acid. The total phenolic compounds contents were also highly correlated with the DPPH method and the FRAP assay.

Total Phenolic Content and Antioxidant Activity of Myrtle (Myrtus communis) Extracts

The total phenolic content and antioxidant activity of methanolic, ethanolic and aqueous extracts of myrtle ( Myrtus communis) leaves and berries were measured to find new potential sources of natural antioxidants. Total phenolic content was assessed by the Folin-Ciocalteau assay, while the antioxidant activity was evaluated by three methods: diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity assay, the reducing antioxidant power assay and β-carotene linoleic acid assay. The total phenol content of myrtle extracts ranged between 9.0 and 35.6 mg GAE per g extract. For each solvent, leaf extracts contained significantly higher amount of total phenolic compounds than berry extracts. All of the extracts presented antioxidant capacity assessed by the three methods, but at different levels depending on the concentration, the extraction solvent and the part of the plant used. Generally, leaf extracts showed higher antioxidant activities than berry extracts, while the overall antioxidant strength was in the order methanol > water > ethanol in leaf extracts and methanol > ethanol >water in berry extracts. The phenolic content exhibited a positive correlation with the antioxidant activity: DPPH assay showed the highest correlation (r = 0.949), followed by the reducing power assay (r = 0.914) and the lowest for the β-carotene linoleic acid assay (r = 0.722).