Greatest Total Phenolic Content Research Articles

Antioxidant and anti-proliferative properties of Davidson’s plum (Davidsonia pruriens F. Muell) phenolic-enriched extracts as affected by different extraction solvents

The Davidson’s plum (DP; Davidsonia pruriens F. Muell) is a fruit native to Australia that is a rich source of phenolic compounds. This study investigated the effects of various extraction solvents (ethanol, methanol, acetone and water) on total phenolic content (TPC), antioxidant capacity (ABTS, DPPH, CUPRAC, FRAP assays) and anti-proliferative activity (MTT, CCK-8 assays) of DP. Our data revealed that extraction solvents significantly affected the physico-chemical, antioxidant and anti-proliferative properties of DP extracts. Within the tested solvents, ethanol was found to be the optimal solvent for extraction of bioactive compounds from DP as its extract had the greatest TPC (94.13 GAE/g), flavonoids (78.33mg RUE/g), proanthocyanidins (5.33mg CAE/g), anthocyanidins (2.81mg CGE/g), as well as possessed the highest antioxidant capacity and anti-proliferative activity against a panel of cancer cell lines. This included cancers of the pancreas, breast, lung, brain, skin, colon and ovary. Therefore, further investigations should be conducted to identify key bioactive compounds to determine the potential for utilization in the nutraceutical and phytopharmaceutical industries.

Effects of chicken manure and vermicompost teas on herb yield, secondary metabolites and antioxidant activity of lemon basil (Ocimum x citriodorum Vis.)

Effects of chicken manure tea (CMT) and vermicompost tea (VCT) as soil drench on vegetative growth, herb yield, essential oil content, total phenolics, total flavonoids and antioxidant activity of lemon basil (Ocimum × citriodorum Vis.) was evaluated in a two-year field experiment. The greatest plant height and number of leaves and flowers, shoot fresh and dry weight and leaf chlorophyll content were obtained using CMT at either 1:5 or 1:10 dilutions with no significant differences. The highest number of lateral branches and flavonoid content were obtained when CMT at 1:5 dilution was applied. Essential oil content was at its highest level (0.618%) when CMT or VCT were used at 1:10 dilution, while the greatest total phenolic content and total antioxidant activity were obtained at 1:5 dilution of VCT. The results emphasize the possibility of using organic-based compost teas for enhancing herbal yield and important secondary metabolites in aromatic medicinal plants.

Chemical Composition of Five Commercial Gynostemma pentaphyllum Samples and Their Radical Scavenging, Antiproliferative, and Anti-inflammatory Properties

Five Gynostemma pentaphyllum (GP) samples were investigated and compared for their chemical compositions and their antioxidant, antiproliferative, and anti-inflammatory effects. Extracts (50% acetone, 75% ethanol, and 100% ethanol) of the five GP samples (GP1-5) differed in their total phenolic, saponin, and flavonoid contents and in their rutin and quercetin concentrations. The highest level of total flavonoids was 63.5 mg of rutin equiv/g in GP4, and the greatest total phenolic content was 44.3 mg of gallic acid equiv/g in GP1 with 50% acetone as the extraction solvent. GP2 had the highest total saponin content of 132.6 mg/g with 100% ethanol as the extraction solvent. These extracts also differed in their scavenging capacity against DPPH and hydroxyl radicals, although they all showed significant radical scavenging capacity. The 100% ethanol extracts also showed dose-dependently strong inhibition on IL-6 and Ptgs2 mRNA expression and weak inhibition on TNF-α mRNA expression. In addition, GP1 had the highest antiproliferative activity at 3.2 mg equiv/mL concentration in HT-29 human colon cancer cells. The results from this study will be used to promote the application of G. pentaphyllum for improving human health.

Effects of cultivar, orchard elevation, and storage on fruit quality characters of sweet cherry ( Prunus avium L.)

Fruit quality characters were analysed in the sweet cherry cultivars, Burlat, Van, Tragana and Mpakirtzeika, harvested from low (39–59 m), medium (216 m) or high (490–546 m) elevation sites. The effects of storage for 2 or 4 days at 2 °C and 1 day at 20 °C on the fruit antioxidant contents were also evaluated. Tragana and Mpakirtzeika had greater fruit fresh weight (FW) and total soluble solid content compared to Van and Burlat, the latter being the most red colored. Tragana and Burlat had greater total phenolic content and total antioxidant capacity, measured by DPPH extinction, compared to Mpakirtzeika and Van (mean values 204.4 mg vs. 103.7 mg gallic acid equivalent 100 g −1 FW, and 176.1 mg vs. 79.3 mg ascorbic acid equivalent 100 g −1 FW, respectively). The geographic elevation had a marked influence on the cherry antioxidant content in all studied cultivars, apart from Van, with high elevation orchards producing cherries with greater contents of antioxidant compounds compared to lower elevation orchards. Changes in the antioxidant contents during storage were depended on the cultivar and some times on the orchard elevation. Total antioxidant capacity was significantly correlated with total phenolic content in Tragana, Burlat and Mpakirtzeika, but not in Van; nevertheless this was not the case during storage.

Evaluation of pre‐heating and extraction solvents in antioxidant and antimicrobial activities of garlic, and their application in fresh pork patties

SummaryThe objectives of this study were to screen the optimum conditions for antioxidant and antimicrobial activities of garlic as affected by pre‐heating and different extraction solvents, and to evaluate the antioxidant and antimicrobial effects of these extracts in ground meat during refrigerated storage. Methanol extracted garlic had a greater total phenolic content, 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH)‐radical scavenging activity and reducing power than water extracted one (P < 0.05), whereas the latter had a greater yield and iron chelating ability than the former (P < 0.05). Moreover, water extract from fresh garlic (WEFG) and methanol extract from heated garlic (MEHG) produced an inhibition zone against Escherichia coli O157:H7 and Listeria monocytogenes. The addition of garlic extracts (WEFG, MEHG and their combinations WEFMEHG)) to pork patties decreased the pH, hunter a values (redness), thiobarbituric acid substances values and the number of total plate count and Enterobacteriaceae (P < 0.05), while the hunter b values (yellowness) increased (P < 0.05). Results of this study indicated that the use of the garlic extracts was able to control lipid oxidation and microbial growth in pork patties.

Effect of scale color on the antioxidant capacity of onions

The bulb onion ( Allium cepa L.) has been cultivated for thousands of years and used as an important component of human diet. Recent studies suggest that onions can be used to cure, reduce, or prevent some of the health problems such as cancer, cardiovascular diseases, antidiabetic, asthma, antibiosis, and prebiotic effects due to its high antioxidant effect. In this study, we determined the antioxidant capacities of a wide range of onion cultivars; nine commercial cultivars and five advance selections differing in color. The variables tested include bulb size, scale color, total phenolic (TP), total antioxidant activity determined by both “Ferric reducing ability of plasma” (FRAP) and “Trolox equivalent antioxidant capacity” (TEAC). We found that yellow onion had the greatest TP content (3.7 mg GAE/g dw); and, the red group had higher TP mean than the white group (2.2 mg GAE/g dw vs. 1.1 mg GAE/g dw). For the antioxidant capacity measurements, the red group had the greatest means by both methods (15.4 μmol TE/g dw and 9.3 μmol TE/g dw for TEAC and FRAP). Yellow onions had higher TEAC (14.7 μmol TE/g dw vs. 8.7 μmol TE/g dw) and FRAP values (9.8 μmol TE/g dw vs. 5.6 μmol TE/g dw) than white onions. Among the cultivars tested great differences of TP, TEAC and FRAP was observed. The TP content of Me-Tan 88 (8.3 mg GAE/g dw) was two times higher than the yellow group. Yellow color Dayton had the greatest TEAC (20.5 μmol TE/g dw) and FRAP (12.3 μmol TE/g dw) means followed by yellow color Me-Tan 88 (19.4 and 11.4 μmol TE/g dw). The two antioxidant measurements were found to be highly correlated (0.99) where absolute values of FRAP were about 40% less than those of TEAC. The values of TEAC and FRAP were significantly correlated by TP with similar rs (0.74 and 0.73, respectively). TP, TEAC and FRAP were significantly and positively correlated to soluble solids (0.41, 0.43, and 0.40, respectively). Our results suggested that the red onions had higher antioxidant activities than yellow and white onions although yellow onions had the richest phenolic contents.

Radical scavenger and Antioxidant activities of extracts and fractions from Bulgarian Ononis spinosa L. and GC-MS analysis of Ethanol extract

Extracts and fractions from Ononis spinosa roots were investigated for their radical scavenging activity using two different in vitro assays, 1,1-diphenyl-2-picrylhydrazyl free radical (DPPH) and 2, 2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). The antioxidant potential measurements were expressed as Trolox equivalent antioxidant capacity (TEAC). The chloroform fraction possessed the highest radical scavenging activity (RSA) in both assays, DPPH (0.235 mmol g) and ABTS (0.264 mmol g). Total phenolic content was also determined using Folin–Ciocalteu reagent. The greatest total phenolic content was detected in the EtOAc and CHCl3 fractions from EtOH extract (108.7 mg/g GAE and 102.1 mg/g GAE, respectively). A correlation between radical scavenging capacities of samples with total phenolic compound content was not observed. GC-MS analysis of CHCl3 fraction showed that the triterpene 9, 19-cyclo-27-lanostan-25-on was the major constituent (13.17%), followed by s-sitosterol (9.61%), medicarpin (9.4%), maackiain (8.01%) and linolic acid (7.98%).

Effect of soaking, boiling, and steaming on total phenolic contentand antioxidant activities of cool season food legumes

The effects of soaking, boiling and steaming processes on the total phenolic components and antioxidant activity in commonly consumed cool season food legumes (CSFL’s), including green pea, yellow pea, chickpea and lentil were investigated. As compared to original unprocessed legumes, all processing steps caused significant (p<0.05) decreases in total phenolic content (TPC), DPPH free radical scavenging activity (DPPH) in all tested CSFL’s. All soaking and atmospheric boiling treatments caused significant (p<0.05) decreases in oxygen radical absorbing capacity (ORAC). However, pressure boiling and pressure steaming caused significant (p<0.05) increases in ORAC values. Steaming treatments resulted in a greater retention of TPC, DPPH, and ORAC values in all tested CSFL’s as compared to boiling treatments. To obtain cooked legumes with similar palatability and firmness, pressure boiling shortened processing time as compared to atmospheric boiling, resulted in insignificant differences in TPC, DPPH for green and yellow pea. However, TPC and DPPH in cooked lentils differed significantly between atmospheric and pressure boiling. As compared to atmospheric processes, pressure processes significantly increased ORAC values in both boiled and steamed CSFL’s. Greater TPC, DPPH and ORAC values were detected in boiling water than that in soaking and steaming water. Boiling also caused more solid loss than steaming. Steam processing exhibited several advantages in retaining the integrity of the legume appearance and texture of the cooked product, shortening process time, and greater retention of antioxidant components and activities.

Total Phenolic Content and Antioxidant Properties of Eclipse Black Beans (Phaseolus vulgaris L.) as Affected by Processing Methods

The effects of soaking, boiling, and steaming processes on the phenolic components and antioxidant activity of black beans were investigated. All processed beans exhibited significantly (P < 0.05) lower antioxidant activities than raw beans in total phenolic content (TPC), DPPH free radical scavenging activity (DPPH), and oxygen radical absorbing capacity (ORAC). Steaming processes resulted in a greater retention of TPC and ORAC values than the boiling processes. Pressure boiling shortened processing time compared to regular boiling, resulted in insignificant differences in TPC, but significantly increased in ORAC as compared to the regular boiling method. Pressure steaming resulted in significant decreases in TPC, DPPH, while significantly increased in ORAC compared to regular steaming. Greater TPC, DPPH, and ORAC values were detected in boiling water than in the soaking and steaming water. Mass balance analysis showed that boiling caused more dry solid loss than steaming. All of these results indicated that processing methods significantly changed contents and activities of antioxidant components of black beans. Steam processing exhibited several advantages in appearance and texture of the cooked product, shortening processing time, and in greater retention of TPC and antioxidant activities. Steam processing may be used to develop high-quality health-promoting black bean products.

Antioxidant activity of extracts from the bark of Chamaecyparis lawsoniana (A. Murray) Parl.

Abstract The bark of Chamaecyparis lawsoniana (A. Murray) Parl. was extracted with methanol and sequentially partitioned with n-hexane, ethyl acetate, n-butanol and deionized water. The antioxidant activities of the four extracts were evaluated using the DPPH• and ABTS+• methods. The total phenolic content of the extracts was determined using the Folin-Ciocalteu method and expressed as gallic acid equivalents (GAE). Butylated hydroxytoluene was used as a positive control in the radical-scavenging activity tests. All the bark extracts showed significant radical-scavenging activity. In the ABTS+• assay, n-butanol extracts exhibited the strongest radical-scavenging activity, followed by ethyl acetate, water, and n-hexane extracts. The greatest total phenolic content was 428.54 mg GAE per gram of dry extract and was detected in the n-butanol extract, followed by the ethyl acetate and n-hexane extracts. The antioxidant activities correlate with the amount of phenolics present in these extracts. The ethyl acetate and n-butanol extracts were rich in phenolics and may represent a good source of antioxidants.

The effect of some processing variables on non-coloured phenolic compounds in port wines

The non-coloured phenolic fraction of fortified port wines was studied. Trials using several mash-extraction techniques which may be used during port wine making were evaluated for their effectiveness by measuring qualitative and quantitative differences in phenolics. Total phenolic compounds measured by spectrophotometry and HPLC analysis were compared, and the greater values obtained using spectrophotometry are attributable to the contribution of anthocyanins and non-phenolic UV-absorbing compounds. Quantitative and qualitative differences in composition were observed depending on the extraction mode. The greatest total phenolic content was found in port wine made by traditional foot treading, while early addition of extra alcohol to the mash had a neutral or negative effect on the yield of phenolic compounds.