FRAP Antioxidant Activity Research Articles

Salinity-induced modulation of growth and antioxidant activity in the callus cultures of miswak (Salvadora persica).

Miswak (Salvadora persica Linn.) is a medium-sized tree, desert facultative halophytic plant. Besides edible fruits and non-edible seed oil, the plant contains several bioactive compounds like alkaloids, tannins, saponins and sterols related to food and cosmetic industries. In the present study, physiological responses and antioxidant potential under salinity stress were investigated in callus cultures of S. persica to evaluate its use as a source of antioxidant. The callus cultures were grown on MS medium supplemented with 0.5 mg/l each of 2,4,5-T and BAP, which could be established successfully by regular subcultures of slow growing callus on this medium for several months. Increased dry weight, soluble proteins, proline, soluble carbohydrates and CAT activity were recorded under NaCl stress in comparison to control cultures. The DPPH and FRAP antioxidant activities were gradually elevated in NaCl-treated callus, whereas SOD quenching was recorded maximum at 200 mM. A significant correlation between antioxidant capacity and phenol content was observed, indicating that phenolic compounds are the major contributors to the antioxidant potential in S. persica. These findings suggest that increased salinity stress caused elevated antioxidant potentials and the plants grown in such conditions may serve as potential source of antioxidant.

Essential oil composition and antioxidant activity of Stachys sylvatica L. (Lamiaceae) from different wild populations in Kosovo

Leaves and inflorescences of Stachys sylvatica L. (Lamiaceae) were collected from three different wild populations in Kosovo to study the natural variation of the chemical composition of essential oils, total flavonoids, total phenolics and the antioxidant activity. Essential oils were obtained by steam distillation and analysed by GC-FID and GC–MS, whereas total flavonoids, total phenolics and antioxidant activities were determined by spectrophotometric methods. Yields of essential oils ranged from 0.001% to 0.007% (v per dry weight). Twenty-eight volatile constituents were identified. The main constituents were α-pinene, β-pinene and germacrene-D. Total phenolics ranged from 39.3 to 70.8 mg g−1 dry mass, whereas total flavonoid content ranged from 30.44 to 70.63 mg g−1 dm. The antioxidant activity, as measured by the DPPH method, exhibited a rather high degree of activity ranging from 25.5% to 57.2%, whereas the FRAP antioxidant activity showed a lower variability and ranged from 93 to 133.4 mg g−1 dm.

In vitro Antioxidant, Xanthine Oxidase and Acetylcholinesterase Inhibitory Activities of Balanites aegyptiaca (L.) Del. (Balanitaceae)

The present study aimed to test the validity of Balanites aegyptiaca remedies used for the treatment of rheumatisms and mental disorders by examining the antioxidant, xanthine oxidase and acetylcholinesterase inhibitory activities of galls and leaves extracts and fractions. The total phenolics and flavonoids were measured using Folin-Ciocalteu and AlCl3 reagents, respectively. Two methods i.e., FRAP and ABTS were used to estimate the total antioxidant capacity of the plant materials. The FRAP and ABTS antioxidant activities showed that among all extracts and fractions tested, the best antioxidant activities were found with the galls dichloromethane and the leaves ethyl acetate fractions. The antioxidant activities did correlated significantly with the total phenolic and flavonoid contents. The study also showed that B. aegyptiaca galls and leaves fractions exhibited a moderate xanthine oxidase inhibitory activity comparatively to the acetylcholinesterase which was weakly inhibited by the tested extracts and fractions.

Optimisation of Polyphenols Extraction from Chestnut Shell by Response Surface Methodology

The extraction of polyphenols from a waste product from the food industry, the shell of the chestnut fruit, was examined with the aim of analyzing the potential of the extracts for the formulation of wood adhesives, for leather tanning and as natural antioxidants. Experiments were planned according to a 23 factorial design to analyze the influence of temperature and Na2SO3 and NaOH concentrations on extraction yield and on different extract properties: Stiasny number, total phenols, tannins and non-tannins contents, tannin/soluble solids ratio, proanthocyanidins content, antioxidant activity, average molecular weights, surface tension and power law rheological parameters of extract aqueous solutions. Extraction yields in the range 26.1–56.4% together with extract Stiasny numbers higher than 84 and total phenols contents and FRAP antioxidant activities in the range 10.86–33.33 g GAE/100 g shell and 92.05–166.32 mmol AAE/100 g shell, respectively, demonstrated the potential of chestnut shell extracts in the formulation of adhesives and as sources of antioxidant compounds. Additionally, the surfactant character and pseudoplastic behaviour of chestnut shell extracts solutions could improve wood wettability when used in adhesive formulation. Under a range of operating conditions, extracts with tannin content higher than 10% and tannin/soluble solids ratio higher than 0.6 were obtained that could be used as tanning agents. The experimental design performed demonstrated the capacity of chestnut shell extracts for the applications proposed and allowed selecting the optimal extraction conditions for obtaining not only high quality extracts but also high extraction yields.

CHESTNUT BURS AS A SOURCE OF NATURAL ANTIOXIDANTS

The potential of chestnut bur as a source of natural antioxidants has been studied. Extracts in solvents of varying polarity (acetone, ethanol, methanol and water) were obtained and compared with respect to extraction yield, total phenols content, antioxidant activity, molecular weight distribution and composition. The extraction with water led to the highest extraction yield (21.2%) and extract total phenols content (37.6 g GAE/100g), FRAP antioxidant activity (2120 nmol AAE/mg extract), DPPH and ABTS radical scavenging activity (3.68 and 3.59 mmol TRE/g extract, respectively) together with the lowest EC50 values for the DPPH (0.044 mg/mL) and ABTS (0.337 mg/mL) essays. The extraction yield, the extract total phenols content and the antioxidant activity (FRAP, DPPH and ABTS) decreased when the polarity of the solvent decreased (water >methanol>ethanol>acetone) and the EC50 values increased in the same order. Chestnut bur extracts have been characterized as hydrolysable gallotannins as revealed its MALDI-TOF spectrum showing a major peak series exhibiting a mass increment of 152 Da corresponding to the repeat unit of the galloyl group. In addition to gallic acid esters of glucose, ellagic acid, quercetin, quercetin-3βD-glucoside and vescalagin/castalagin were found in chestnut bur extracts.

Antioxidant activity and phenolic content of chestnut ( Castanea sativa) shell and eucalyptus ( Eucalyptus globulus) bark extracts

Chestnut ( Castanea sativa) shell and eucalyptus ( Eucalyptus globulus) bark, waste products of the food and wood industries, respectively, were analysed as potential sources of antioxidant compounds. The extraction yield, the antioxidant activity and total phenols content of the extracts were greater in chestnut shell than in eucalyptus bark for most of the extraction conditions essayed. Extraction of chestnut shell with a 2.5% Na 2SO 3 aqueous solution led to the highest extraction yield, 25.6%, total phenols, 13.4 g gallic acid equivalent/100 g oven-dried shell, and FRAP antioxidant activity, 80.7 mmol ascorbic acid equivalent/100 g oven-dried shell. Extraction with methanol:water (50:50, v/v) provided the best results for eucalyptus bark. The antioxidant activity and the total phenols content of the extracts had a positive linear correlation. FTIR spectroscopy confirmed the higher content of phenolic compounds in chestnut shell extracts compared to eucalyptus bark extracts. Chestnut shell extracts were characterized by the presence of high molecular weight species whereas lower molecular weight species were predominant in eucalyptus bark extracts.