Antioxidant Activity Evaluation in a Series of Heterocyclic Compounds Derived from 1,8-Diaminonaphthalene

From (2,3-dihydro-1H-perimidin-2-yl)-phenyl, the substitution of OH group in ortho or para position on the phenyl ring, allows us to synthesize the studied compounds. These three compounds have been characterized by conventional spectroscopic methods (NMR and MS). The interest of this work is to review the antioxidant activity of our compounds. The antioxidant activity screening carried out according to FRAP and DPPH methods revealed significant anti-free radical properties for compounds 1 and 2 even at low concentrations. In contrast to the compound 2, compound 3 for which the OH group is substituted in para position has the lowest activity in both cases. Therefore the para position seems to be the least sensitive position to increase the antioxidant activity of this pharmacophore.

A Comparative Study of Antioxidant Activities between Fresh and Dry Mushrooms in the Genera <i>Cantharellus</i>and <i>Afrocantharellus</i>from Tanzania

Cantharellus and Afrocantharellus mushrooms are widely consumed in both fresh and dry forms. However, their antioxidant and whether their values changing with drying processes are not known. This study establishes their values and the effect of sun drying on their quality and quantity. Methanolic extracts of five Cantharellus and two Afrocantharellus species were investigated. The investigation used (1,1-diphenyl-2-picrylhydrazyl radical) DPPH as a substrate to determine radical scavenging abilities. Further quantitative analyses for carotenoids, flavonoid, total phenolic compounds and vitamin C content were done using spectrophotometric assay at 515 nm. Comparatively, fresh mushroom had higher vitamin C and Lycopene contents than their dry counterparts with β-carotene. Flavonoid and phenolic compounds were higher in dry forms than those in their fresh counterparts. Radical scavenging ability also varied with fresh forms depicting higher activity compared to dry forms. The variation was low in Afrocantharellus species (0.8% and 0.99%) while it was higher in Cantharellus species (24.12% and 7.52%). The highest ability was observed in fresh forms of Cantharellus pseudocibarius (EC50 50 = 0.4 mg/ml) was from dry form of Cantharellus rufopunctatus. This shows that studied mushrooms are rich in antioxidants and their quality and quantities are affected differently in both forms. Both dry and fresh mushrooms are potential sources of natural antioxidants. The portrayed high scavenging ability by these mushrooms envisages promoting them into potential nutraceutics.

The Application of Novel Electrochemical Approach to Antioxidant Activity Assay of Metal Porphyrins with Bulky 3,5-Diisobornyl-4-hydroxyphenyl Moieties

The complexes of biogenic metals (Zn2+,Cu2+,Co2+,Mn3+,Fe3+) based on meso-tetra(3,5-diisobor- nyl-4-hydroxyphenyl)porphyrin 1 were synthesized. The electrochemical behavior of these com-pounds was studied using cyclic voltammetry (CV) and rotating disk electrode (RDE) techniques. The antioxidant activity of complexes was estimated by means of the electrochemical assay based on the hydrogen atom transfer reaction to the stable radical 2,2’-diphenyl-1-picrylhydrazyl (DPPH). The RDE method was applied for this process monitoring. It was shown that the efficiency of the metal complexes (Cu2+,Co2+,Mn2+,Ni2+,Fe3+) is practically the same order as that of free base porphyrin 1. However the Zn2+ complex demonstrates significantly higher antioxidant activity, and the stoichiometry of the reaction was determined as σ = 4. The results demonstrate that porphyrin macrocycle can directly affect the antioxidant properties of 2,6-diisobornylphenol.

Comparison of Antioxidant Activities of Silver Nanoparticles and Methanol Extracts of Three Indigenous Nigeria Herbal Seeds

The antioxidant of seeds was carried out using extracts from methanol and Silver Nanoparticles from the spice. The SEM shows the shapes, dispersion and agglomeration of the sample, while the EDX confirms the SEM and the presence of some compounds. The FT-IR reveals the AgNPs capping and reducing the particular biomolecule from the functional group for identification. Compounds found in the FT-IR seeds of Capsicum annum are Ag L (Silver iodide), C K (Cyanogen chloride), P K (Phenol). Monodora myristica are Mo L (Molybdenum), Ag L (Silver iodide), C K (Cyanogen chloride), P K (Phenol), Mg K (Magnesium). Piper guineense are Ag L (Silver iodide), Ci K (Potassium chloride), C K (Cyanogen chloride), P K (Phenol). The seeds show that the AgNPS of CA and MM has a better antioxidant activity than the methanol of CA and MM, while the PG methanol has a better activity than the AgNPS PG. The control (Catechin and Galic acid) has a slight overall better DPPH activity than the AgNPS. It is important to note that there is a concentration dependency in CA, MM AgNPS, PG methanol respectively. Notably, at CA methanol, the conc. at 125 was higher than the conc. at 250. Hence, there is need to create a great part in using plant samples for making tabulated or capsulated drugs for treatment of diseases and using plant silver nanoparticles to develop a healthy food/drug preservative package material “smart packaging” that will enhance shelf-life.

Optimization of Extraction of Antioxidants from Turmeric(Curcuma longa L.) Using Response Surface Methodology

Turmeric is a spice widely used to enhance the taste and color of certain meats. We investigated the antioxidant capacities of turmeric ethanol soaking extracts by utilizing the scavenging properties of hydroxyl radical and 1,1-diphenyl-2-picrylhydrazyl（DPPH） free radical. The results showed that the optimum extraction parameters were： extraction time 4 h, sample-solvent ratio 1：84.12, solvent 72.34% ethanol solution, and water bath temperature 81.3 ℃. The optimum ethanol soaking extraction parameters were： extraction time 4 h, sample-solvent ratio 1：90.74, solvent 80.46% ethanol solution, water bath temperature 88.2 ℃. With these parameters, the hydroxyl radical scavenging rate and the DPPH free radical clearance of crude extracts from turmeric can reach about 93.78% and 40.69%, respectively. These results indicate that ethanol soaking extraction may be a useful method for extracting antioxidants from turmeric.

Antioxidant,phytotoxic and cytotoxic activity of methanolic extract of Trigonella foenum-graecum

Objective:To analyze the methanol extract of Trigonella foenum-graecum(T.foenum-graecum)for antioxidant,phytotoxic and cytotoxic activity.Methods:The powder of T.foenum-graecum was extracted in diluted methanol with the help of random shaking method.All extracts of the plant were measured for cytotoxic activity(beside brine shrimp and antioxidant activity vs.1,1-diphenyl-2-picrylhydrazyl free radical).Results:Various concentrations of methanolic extract of T.foenum-graecum were observed as 36.16%to 54.12%with rising concentrations of 50 to 1000μg/mL.Significantly phytotoxic activity(100 and 1000μg/mL)reduced the growth of roots(radicals)and shoots(hypocotyls)of rice when compared to control after 3 and 7 days’treatment.At a concentration of 10μg/mL,the survival rate of cytotoxic activity of brine shrimp was maximum and at a concentration of 250μg/mL,the death rate of brine shrimp was maximum.Conclusions:T.foenum-graecum has potential activity against free radical mediated sickness and thus it is possible to treat cancer.