Phytochemical, Antioxidant and Free Radical Scavenging Activities of Ethanol Extract of Costus afer, Sida acuta and Irvingia gabonensis

Antioxidants are free radical scavengers found in spices which may play a significant role in preventing cell death. Allspice is a dried unripe berry obtained from the Pimento dioica plant that may have antioxidant potential. The objective of this study was to determine the total phenolic, flavonoid content and antioxidant capacity of allspice using selected assays such as 2,2-diphenyl-1-picrylhydrazyl (DPPH), Ferric Reducing Antioxidant Potential (FRAP) and Trolox Equivalent Antioxidant Capacity (TEAC), Nitric Oxide (NO) and Oxygen Reducing Antioxidant Capacity (ORAC). Total phenolic and flavonoid contents of allspice were determined using both water and methanol extraction. A comparison of antioxidant activity of water and methanol extracts of allspice was conducted using the different assays (DPPH, TEAC, NO, ORAC and FRAP). The total phenolic content (6.9%), NO scavenging (38.8%) and ORAC (35.1%) activity were higher in methanol compared to water extracts of allspice while flavonoids (57%), FRAP (11.2%), and TEAC (1.82%) were higher in water extracts compared to methanol extracts of allspice. The total phenolic and flavonoid content were higher in methanol extracts compared to water extracts of allspice. The IC50 (DPPH), FRAP and TEAC, NO scavenging and ORAC activity were higher in methanol extracts compared to water extracts of allspice. Total flavonoid content, FRAP and TEAC, NO scavenging and ORAC were significantly higher (p ≤ 0.5) in methanol extracts compared to water extracts of allspice. This shows that allspice has antioxidant potential and that the method of extraction can play a crucial role on the number of phytochemicals extracted from the plant. Utilization of allspice in food products may provide additional functional properties.

Phenolic and flavonoid contents in plants play a great role in scavenging free radicals in the body and act as antioxidants; thus making their determination very vital. Total phenolic and flavonoid contents of the methanol extract of Voacanga africana root bark and its fractions (n-hexane, ethyl acetate and n-butanol) were carried out in this study. The total phenolic content was determined by using Folin-Ciocalteau assay while the the total flavonoid content was determined by the aluminium chloride colorimetric assay method. The result obtained showed that n-hexane fraction of the plant exhibited the highest (116.607±95.13 mgGAE/g) total phenolic content (TPC) at all concentrations followed by ethyl acetate fraction of the plants. The highest total flavonoid content across concentrations (300, 250, 200, 100, 50 and 25 μg/ml) was exhibited by n-hexane fraction (467.143±44.22 mg QE/g). From the results, it was concluded that n-hexane fraction of V. Africana root bark exhibited the highest total phenolic and total flavonoid contents at all concentrations (ppm), followed by ethyl acetate. It could be deduced that V. africana root bark possesses phenolic and flavonoid contents depending on the type of extract or fraction; thus justifying its folkloric use in the treatment of diseases.Keywords: Phytochemicals, Phenols, Flavonoids, Voacanga africana, Root bark, Fraction

The research aimed to evaluate quality profiles, optimize the antioxidant activity, and total phenolic and flavonoid content in a mixture of three crude drug: turmeric, java tea, and seed-under-leaf, using the Simplex Lattice Mixture Design. Ultimately, a quadratic model was used, as it best adjusted to the experimental behavior. It predicted the optimal composition of herbal mixtures antioxidant activity, determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging and Ferri Reducing Antioxidant Power (FRAP) techniques, also in Total Phenolic Content (TPC) and Total Flavonoid Content (TFC). The crude drugs were of good quality according to selected pharmacognostic quality parameters of the official Malaysian herbal monograph (MHM). The optimum responses with the highest synergistic effect were composed of 5% (w/w) of turmeric, 40% (w/w) of Java tea, and 55% (w/w) of seed-under-leaf. The values were 1796 mM TE/g, 2230 mM TE/g, 355 mg GAE/g, and 177 mg QE/g for DPPH, FRAP, TPC, and TFC, respectively. The greatest contribution of antioxidant activity was shown in that mixture as potential as a functional beverage.

The objective of the present study was to determine the total phenolic content (TPC), total flavonoid content (TFC) and antioxidant properties, i.e. 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay and ferric reducing antioxidant potential (FRAP) assay, of red- and yellow-fleshed watermelon rind powders prepared using different drying conditions (hot-air oven drying at 40 and 60°C and freeze drying). All the samples were subjected to four different solvent extract using water, methanol, ethanol and acetone prior analyses. Water extract from red- and yellow-fleshed watermelon rind powders presented highest value for TPC and TFC. However, methanol extract samples showed highest value for antioxidant properties (DPPH and FRAP) followed by acetone, ethanol and water extract. By comparing the drying conditions, all samples dried using hot-air dryer at 40 and 60°C had significantly higher (p<0.05) in TPC value than the samples dried using freeze dryer. However, samples dried using freeze dryer showed highest in DPPH and FRAP values. The present obtained results would be useful to the food and pharmaceutical industries for developing of functional ingredients.

Quercetin was isolated from ethyl acetate fraction of a methanol extract of the outer scale of onion by repeated sephadex LH-20 column chromatography. Methanol, 50% aqueous methanol and 70% aqueous acetone extracts of different parts of four medicinal plants, Ficus benghalensis, Elaeocarpus sphaericus, Ipomea carnea and Azeratum conyzoides were prepared and screened for total phenolic and flavonoid contents and free radical scavenging activity. The total phenolics contents were measured spectrophotometrically by using Folin-Ciocalteu reagent and total flavonoids content by using aluminum chloride colorimetric method. Free radical scavenging activity was evaluated using 2,2-diphenyl-1-picryl-hydrazyl (DPPH) assay. All the investigated medicinal plant extracts contained high amount of phenolics. The highest amount was detected in 70% aqueous acetone extract of E. sphaericus (298.8±9.03 mg GAE/g extract) and lowest amount in 50% aqueous methanol extract of F. benghalensis (6.7±0.73 mg GAE/g extract). The highest amount of flavonoid was found in methanol extract (78.2±2.72 mg quercetin/g extract) and the lowest amount was detected in 50% aqueous methanol extract (2.1±0.25 mg quercetin/g extract) of F. benghalensis. DPPH free radical scavenging assay was carried out only in 70% acetone extracts. The highest IC50 value was observed for E. sphaericus (34.0 μg/ml). A strong linear correlation between total phenolic content and antioxidant activity was found indicating that the major antioxidants are phenolics.DOI: http://dx.doi.org/10.3126/njst.v15i1.12010 Nepal Journal of Science and Technology Vol. 15, No.1 (2014) 53-60

Kenaf (Hibiscus cannabinus L.) is a valuable plant with a potential health benefit because of its extensive bioactive compounds. Leaf extracts of 33 kenaf genotypes were investigated for their polysaccharide, total phenolic, and flavonoid content. The antioxidant properties were evaluated by 2,2-Diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS), and ferric reducing antioxidant potential (FRAP) assays. Antimicrobial capacity was also assessed against Staphylococcus aureus and Escherichia coli using a disc diffusion assay. The polysaccharide content varied from 6.45–16.12 mg glucose per g DW. Total phenolic and flavonoid content ranged from 6.03–21.15 mg GAE/g DW and 1.55–9.24 mg RE/g DW, respectively. Similarly, varied values in the range 20.55–79.99% of inhibition by DPPH, 56.28–88.30% of inhibition by ABTS and 1.26–5.08 mmol Fe2+/g DW by FRAP assays were obtained for antioxidants of the genotype extracts. Extracts from CS4 and CS2 genotypes had the highest antioxidant activities. Kenaf leaves exhibited antibacterial activity against Staphylococcus aureus and Escherichia coli. Strong correlation was found between antioxidant activity with polysaccharide (DPPH, r = 0.893; ABTS, r = 0.819; FRAP, r = 0.864) and total phenolic content (DPPH, r = 0.850; ABTS, r = 0.959; FRAP, r = 0.953). The results suggested that the kenaf leaves could be used as a natural antioxidants and antimicrobial in food industries.

Lagenaria siceraria (bottle gourd) fruit is highly celebrated for its nutritional as well as therapeutic properties. The present study was undertaken with the aim of exploring an efficient green solvent-free microwave-assisted extraction method for bioactives from this fruit. Optimization was done according to response surface methodology (RSM), where microwave power (W) and time (s) were independent factors, and percent extraction yield, total phenolic content (TPC), total flavonoid content (TFC), 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, ferric reducing antioxidant potential (FRAP) and iron chelating activity (ICA) were the responses. TPC, TFC, DPPH radical scavenging activity, FRAP and ICA were highest at 480 W and 60 s. The TPC was 288.9 mg GAE · g−1 DW (milligram gallic acid equivalent per gram dry weight), TFC was 214.1 mg RE · g−1 (rutin equivalent per gram DW), anti-radical activity was 32.96%, FRAP was 289.7 mg AAE · g−1 (mg ascorbic acid equivalents per gram) and ICA was 19.52%. The results of the study thus demonstrate that the solvent-free microwave-assisted extraction method, which utilised an optimum power of 480 W and a time of 60 s, is an effective and green method for extraction of antioxidant compounds from bottle gourd fruit.

Aims: Plants need an appropriate amount of nutrients such as copper for growth and development. However, excess of copper may interrupt plant development and cause stress that led to biochemical compounds being synthesized. The influence of a high copper sulfate concentration on phenolic and flavonoid content in Phyllanthus tenellus plants was investigated.&#x0D; Place and Duration of Study: The experiment was conducted in a government compound at MARDI Serdang, Selangor, Malaysia (2° 59' 31.7292'' N 101° 41' 56.706'' E), from April 2021 to Jun 2021.&#x0D; Methodology: The experiment was conducted using a vertical column planting system under a side-netted rain shelter. The plants were subjected to 0.5 M copper sulfate sprayed after 60 days of planting and harvested 0.5, 1.5, 3, 6, 12 and 24 h after sprayed for further analysis. Total phenolic content was calculated as mg gallic acid equivalent and total flavonoid content was measured as quercetin equivalent.&#x0D; Results: Highest total phenolic and flavonoid content was detected after 0.5 hours of copper sulfate application and started to decrease towards 24 hours after sprayed. Treated samples showed a 1.18-fold increase in total phenolic content and 1.4-fold increase in total flavonoid content compared to control untreated samples after 0.5 hours of sprayed. Control samples showed stability in both total phenolic and flavonoid content throughout the harvesting periods. Phenolic is the major secondary metabolites in Phyllanthus tenellus plants.&#x0D; Conclusion: Data revealed that the application of 0.5 M copper sulfate is able to enhance total phenolic and flavonoid content in Phyllanthus tenellus plants. The study suggested that the optimum harvesting time is 0.5 hours after copper sulfate application.

The focus of the present study was to determine the association of the anti-oxidant activity of Costus speciosus (Koen Ex. Retz.) Sm. with the total phe-nolic content and the total flavonoid content. The antioxidant activity of the extracts was quantified by diphenylpicrylhydrazyl (DPPH) assay. The total phenolic content was determined by the Folin-Ciocalteau method and the total flavonoid content was determined by the aluminium chloride method. Among the four extracts of the plant, the ethanol extract exhibited the high-est antioxidant activity and also the highest total phenolic and flavonoid con-tents. A strong correlation was observed between the antioxidant activity and the total phenolic and flavonoid contents. A statistical model was de-rived to explain this dependence and a non-linear association was observed between the antioxidant activity and the total flavonoid content.

Effects of different calcium chloride, chitosan and pullulan coating treatments on antioxidant activity of “Huang guan” pears (Pyrus pyrifolia Nakai) during storage have been studied. Total phenolic content, phenolic composition, total flavonoid content, superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities, and antioxidant activity (1,1-diphenyl-2-picrylhydrazyl (DPPH), 2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid (ABTS), ferric reducing antioxidant potential (FRAP)) were determined in peel and pulp tissues over 210 days. Coating treatments slowed decrease of total phenolic and flavonoid contents, chlorogenic acid, arbutin, catechin and caffeic acid, SOD and CAT activities, and total antioxidant activity. However, POD activity was inhibited. The antioxidant content in the peel was higher than in the pulp. Of the coatings, chitosan was the most effective, but overall, all coatings may be useful to extend shelf-life, maintain quality and control decline of antioxidant activity in pear.

Aims: This study aimed to investigate the total phenolic and flavonoid content and DPPH free-radical scavenging activity of Vernonia amygdalina planted in Mekong Delta. The optimized conditions for maceration of pandan leaves included drying method, ratio of pandan leaf powder-to-solvent, and extraction time.&#x0D; Methodology: The fresh pandan leaves were divided into two equal portions, subjected to different drying methods: shade and oven drying. The dried leaf powder was macerated in ethanol at room temperature. The maceration was conducted with 3 different ratios of pandan leaf powder-to-solvent (w/v) (1:10, 1:15 and 1:20), and the extraction time was 1, 2 and 3 days. The total flavonoid content was determined using aluminum chloride method whereas the total phenolic content was assessed using Folin-Ciocalteu assay. Meanwhile, the antioxidant activity of the plant extracts was quantitatively evaluated using DPPH test.&#x0D; Results: The results indicated that the best conditions for maceration of pandan leaves were 1:10 shade-dried leaf powder-to-solvent ratio in 1-day extraction time. Accordingly, the total flavonoid and phenolic content was found to be the highest value of 130.02 ± 2.24 mg QE/g of dried extract and 100.67 ± 1.76 mg GAE/g of dried extract (p &lt; 0.05), respectively. The lowest IC50 of DPPH free-radical scavenging activity of pandan leaf extract was found to be 0.90 ± 0.02 mg/mL (p &lt; 0.05). In addition, the Pearson’s correlation coefficient between IC50 of DPPH free-radical scavenge activity and total flavonoid content was R2 = 0.74 compared to that of phenolic content with the value of R2 = 0.69, indicating that the IC50 of DPPH free-radical scavenge capacity of pandan leaves was influenced chiefly by flavonoid compounds.&#x0D; Conclusion: There was a significant difference in phenolic and flavonoid content and DPPH free-radical scavenging activity between shade-dried and oven-dried pandan leaf extracts.

Objective: To investigate the antioxidant activity of extracts of aerial parts of Gladiolus segetum and determination of their total phenolics and flavonoids content. Material and methods: A detailed study was performed on the antioxidant activity of the extracts of Gladiolus Segetum (GS) by employing established in vitro systems using DPPH and ABTS radical scavenging capacity, the s-carotene-linoleic acid assay, CUPRAC, ferric reducing antioxidant potential (FRAP) and metal chelation. Total phenolic content was determined by the Folin-Ciocalteu method and flavonoids was also determined by the trichloroaluminum method. Results: The total phenolic contents (TPC) (64, 96±1,08 mg GAE/g extract) of methanol extract of GS while total flavonoid contents (TFC) (39,79±2,36 mg QE/g extract) were found significantly higher as compared to other extracts. The EC50 values of methanol extract of GS based on the DPPH (118,29±0,64µg/ml), ABTS (23,76±2,02 µg/ml), s-carotene (29,67±1,99 µg/ml), CUPRAC (47,34±4,50 µg/ml), FRAP (55,34±0,69 µg/ml) and metal chelation (40,80±1,71 µg/ml) were generally lower showing potential antioxidant properties. Conclusion: Methanolic extract of GS showed the highest phenolic and flavonoid concentrations and strong antioxidant activity. The Gladiolus segetum can be regarded as promising candidates for natural plant sources of antioxidants with high value.

Tea fermentation relates to the enzymatic oxidation of the leaves of the tea and the formation of dark pigments. This method is usually conducted in a setting where temperature and humidity can be regulated. However, the impact of fermentation time on the antioxidant characteristics of Napier grass herbal tea is still unanswered. This study aimed to determine the effect of fermentation time on antioxidant properties of Napier grass black tea. Napier grass was subjected to fermentation for 3, 6, 9, 12 and 24 hrs. Fresh and dried samples were extracted in water (95°C, 30 mins) and the extracts were then analysed by total phenolic content (TPC) assay, total flavonoid content (TFC) assay, diphenyl-picryl-hydrazyl (DPPH) assay, Ferric reducing antioxidant potential (FRAP) assay, ferric thiocyanate (FTC) method and thiobarbituric acid (TBA) method. Sample fermented for 9 hrs showed the highest results in TPC (18.32±0.38) and FRAP assay (91.00±2.78). Whereas, the highest flavonoids and antioxidant activity were found in dried sample without fermentation (control) in TFC (97.82±13.00) and DPPH (90.02±1.11). However, samples fermented for 3 to 9 hrs showed no significant difference with that of the fresh sample in TFC and DPPH indicating 3 to 9 hrs fermentation time did not affect the antioxidant properties of Napier grass. In FTC and TBA, all the fermented samples showed lower antioxidant activity than that of fresh samples and control. The results suggested that 9 h of fermentation time is suitable for the preparation of Napier grass black tea as it exhibited high antioxidant properties in TPC, TFC, DPPH and FRAP assays.

Phenolic profiles, antioxidant capacities and metal chelating ability of edible mushrooms commonly consumed in China

Background: Nowadays antioxidants have gained a lot of importance because of their potential as prophylactic and therapeutic agents in the diseases caused by free radicals. Presently, the active constituents from the natural sources are tested for their free radical scavenging potential. Plants are of enormous importance in the free radical and antioxidant field. Aim: The present study was carried out to evaluate the free radical potential, total phenolic and flavonoid content of edible and non-commercial fruits of Ziziphus mauritiana and Ziziphus nummularia belonging to the family Rhamnaceae. Materials and Methods: Free radical scavenging potential of methanolic extracts of the Ziziphus mauritiana and Ziziphus nummularia fruits (MEZM and MEZN) was evaluated by 1, 1-diphenyl-2-picryl-hydrazyl (DPPH) and hydrogen peroxide (H2O2) method. The total phenolic content of the methanolic extracts of fruits was determined using gallic acid as a standard. The total flavonoid content was determined using the Aluminium chloride reagent and quercetin as standard. Statistical analysis: The results were statistically analysed with the Student’s t-test. Results and Conclusions: The extracts showed significant free radical scavenging activity in a dose dependent manner when compared with ascorbic acid. The highest DPPH radical scavenging activity of MEZM and MEZN was found to be 79.5% and 77.5% respectively at concentration of 250 μg mL-1. The H2O2 scavenging effect of MEZM and MEZN was 73.4% and 71% respectively at a concentration of 250 μg mL-1. IC50 <1 mg/ ml shows that the fruits possess significant antioxidant activity. The phenolic as well as flavonoid content was found to be higher in MEZM. The fruits can be used as a natural source of antioxidants in combating diseases caused by free radicals. Key words: Antioxidants, free radicals, Rhamnaceae, Ziziphus mauritiana, Ziziphus nummularia