Phytochemical investigation, antioxidant and antibacterial activities of the fruit extracts of Solanum anguivi

Total phenolic and flavonoid contents and antioxidant activity of four Iranian herbs (Lamiaceae) were investigated. The antioxidant activity of methanol extracts of thyme (Thymus daenensis Celak.), Bakhtiari savory (Satureja bachtiarica Bung.), dragonhead (Dracocephalum multicaule Montbr & Auch), and woundwort (Stachys lavandulifolia Vahl.) was evaluated by measuring 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferric reducing/antioxidant power (FRAP), and trolox equivalent antioxidant capacity (TEAC). A comparison of all plant extracts in the DPPH assay indicated that dragonhead and thyme were the most effective free radical scavenging agents. Thyme demonstrated a relatively strong antioxidant activity in both the FRAP and TEAC assays. The total phenolic content of all the extracts ranged from 99 to 208 mg TAE/g extract with thyme exhibiting the highest phenolic content. The flavonoid content of the extracts, which ranged from 10.1 to 22.2 rutin equivalents/g of extract, was highest in dragonhead. A positive correlation was noted between the total phenolic content and antioxidant activity in both the FRAP and TEAC assays, while no significant correlation was observed between the DPPH, TEAC, and FRAP assay and total flavonoid, suggesting that the level of antioxidant activity in these plants varies greatly, but the total phenolic in the plant extracts provided a substantial antioxidant activity. Experimental results indicate that thyme and dragonhead extracts could be an important dietary source of phenolic compounds with high antioxidant capacity.

Objectives: The objectives of this research were to evaluate antioxidant activity from different polarities rice bran extract of three varieties of rice using two methods of antioxidant testing which were FRAP (Ferric Reducing Antioxidant Power) and DPPH (2,2-diphenyl-1-picrylhydrazyl), and correlation of total phenolic, flavonoid and carotenoid content with their EC50 of FRAP and IC50 of DPPH antioxidant activities. Methods: Extraction was conducted by reflux using different polarity solvents. The extracts were evaporated using rotary evaporator. Determination of total phenolic, flavonoid and carotenoid content, antioxidant activities using FRAP and DPPH assays were performed by UV-visible spectrophotometry and its correlation with EC50 of FRAP capacities and IC50 of DPPH scavenging activities were analyzed by Pearson’s method. Results: Ethanolic rice bran extract of black rice showed the lowest EC50 of FRAP capacity 64.35 µg/ml and IC50 of DPPH scavenging activity 23.92 µg/ml. The highest phenolic content, flavonoid content and carotenoid content were also given by ethanolic rice bran extract of black rice. There were significantly negative correlation between total phenolic content and carotenoid content in rice bran extract of red rice and black rice with their IC50 of DPPH. Conclusions: All of rice bran extracts (except n-hexane rice bran extract of black rice and ethanolic rice bran extract of white rice) were very strong antioxidant, by DPPH assay. Phenolic and carotenoid compounds in rice bran extracts of red rice and black rice were the major contributor in antioxidant activity by DPPH assay. Rice bran extracts of black rice had linear results by FRAP and DPPH assays.

Eriobotrya plants are known to have significant amounts of phenolics and flavonoids, and exhibit a strong antioxidant activity. Experiments were conducted to examine variation in the contents of total phenolics and flavonoids, and antioxidant activities in the leaves of 11 Eriobotrya species (Tibet loquat, Daduhe loquat, Hengchun loquat, Taiwan loquat, Oak leaf loquat, Bengal loquat, Fragrant loquat, Guangxi loquat, Obovate loquat, Big flower loquat, and common loquat, the last species include two materials, one is a cultivar 'Zaozhong 6', another is a wild tree). In these species, 'Zaozhong 6' loquat is a cultivar. The leaf extracts of 'Tibet', 'Obovate', 'Taiwan', 'Bengal' and 'Hengchun' loquats exhibited significantly higher contents of total flavonoids and total phenolics, compared with those of other species. Of these 11 species, the highest contents of total phenolics and total flavonoids were observed in 'Tibet' and 'Obovatae' loquats, respectively. The significantly stronger antioxidant abilities assessed by the DPPH radical scavenging activity and reducing power were obtained in the leaf extracts of 'Taiwan', 'Tibet', 'Bengal', 'Oak leaf', 'Hengchun' and 'Obovate' loquats, compared with the other species. In addition, significant correlations were found between the contents of total phenolics or flavonoids and DPPH radical scavenging activity/reducing power. This work indicates that the leaf extracts of the wild Eriobotrya species, 'Tibet', 'Obovatae', 'Taiwan', 'Bengal', 'Oak leaf' and 'Hengchun' loquats, exhibited significantly higher levels of total phenolics and flavonoids, and significantly stronger antioxidant activities, compared with the cultivated species, 'Zaozhong 6' loquat, which suggests that these wild species have a better utilization value.

Canarium odontophyllum, known locally as “Kembayau” or “Dabai”, is a highly seasonal fruit which is popular among local people in Borneo Island. This study was conducted to determine the antioxidant activity, phytochemicals (total phenolic, total flavonoid, total anthocyanin and total carotenoid contents) and acetylcholinesterase inhibitor potential of extracts of the flesh and seed of this fruit. C. odontophyllum was collected in Beaufort, Sabah, Malaysian Borneo and subsequently freeze-dried and extracted using 80% methanol and distilled water. Antioxidant activities were analyzed using DPPH free radical scavenging, ABTS decolourization and FRAP (Ferric reducing / antioxidant power) assays. Anti-Alzheimer’s potential was determined using acetylcholinesterase enzyme inhibition assay. The results showed that the total phenolic and flavonoid contents were higher in the flesh of C. odontophyllum with the values of 11.96 ± 0.05 mg gallic acid equivalent (GAE)/g and 10.11 ± 1.54 mg rutin equivalent (RU)/g, respectively. Total anthocyanin and carotenoid content were also higher in the flesh of the fruit with the values of 12.75 ± 0.28 mg/100g and 2.84 ± 0.11 mg/100g. The flesh of the fruit also showed higher antioxidant activity as assessed using DPPH, ABTS and FRAP assays. However, anti-cholinesterase activity was higher in the seed of C. odontophyllum which showed that possible other phytochemical content (besides phenolic and flavonoid) which might responsible to the observed effects. The same trend of phytochemicals, antioxidant and anti-cholinesterase activity were also observed in the distilled water extract. These findings suggested that C. odontophyllum is not only nutritious but also displayed potential pharmacological properties.

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.
 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.
 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 < 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 < 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.
 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.

Objectives: The goals of this research were to evaluate antioxidant potential from different organs of eggplant (Solanum melongena L.) using two antioxidant testing methods which were 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) and correlation of total phenolic and flavonoid content with their inhibitory concentration 50% (IC50) of DPPH, and exhibitory concentration 50% (EC50) of FRAP.Materials and Methods: Each sample was extracted by reflux using different polarity solvents. The extracts were evaporated using rotary evaporator. Antioxidant activities were tested using DPPH and FRAP assays, determination of total phenolic and flavonoid content were carried out by ultraviolet-visible spectrophotometry and correlation with their IC50 of DPPH and EC50 of FRAP capacities were analyzed by Pearson’s method.Results: The lowest IC50 of DPPH scavenging activity 1.14 μg/ml and the lowest EC50 of FRAP capacity 49.80 μg/ml was given by ethanolic leaves extract of eggplant. Ethanolic leaves extract of eggplant also presented the highest total phenolic content (TPC) (8.87 g gallic acid equivalent/100 g), while the highest total flavonoid content was shown by ethyl acetate leaves extract (24.50 g quercetin equivalent/100 g). There was a significantly negative correlation between TPC in leaves and fruit extracts of eggplant with their IC50 of DPPH and EC50 of FRAP.Conclusions: All different extracts of eggplant organs (except n-hexane stem extract) were categorized as a very strong antioxidant by DPPH method. Phenolic compounds in eggplant leaves and fruit extracts were the major contributor in antioxidant activities by DPPH and FRAP methods. DPPH and FRAP showed linear results in antioxidant activities of eggplant leaves, fruit and stem extracts.

本試驗以綠豆抗豆象品系VC6089A、其近同源但不抗豆象品系VC1973A及日正綠豆 (日正食品工業股份有限公司，南北坊綠豆) 為材料，探討於黑暗中栽培高植化素含量綠豆芽之最適環境條件。綠豆種子於20˚C、26˚C與32˚C浸水0、4、8及12小時，其乾重隨浸種時間延長而降低。以四種密度栽培綠豆芽，收穫指數 (harvest index) 以7 g·cm-2種子最佳，其下胚軸較長、總類黃酮 (total flavonoids) 含量較高；密度試驗中，綠豆芽總酚類含量與收穫指數之間 (r=0.74***) 、總酚類 (total phenolics) 含量及總類黃酮含量之間 (r=0.77***) 皆呈正相關。以壓重0、100、200、300、400 g·51.84 cm-2栽培綠豆芽，VC1973A及日正綠豆於400 g·51.84 cm-2處理下，其豆芽下胚軸較粗短，根長亦較短；壓重試驗中，綠豆芽總類黃酮含量與DPPH自由基清除能力[α,α-diphenyl-β-picrylhydrazyl radical scavenging activity]間，以及總類黃酮含量與FRAP鐵離子氧化還原能力 (ferric reducing antioxidant power, FRAP ) 間之相關係數r分別為0.82***與0.64***。繼以16 h/8 h為一週期，於26˚C/20˚C、26˚C/23˚C、26˚C/26˚C、29˚C/20˚C、29˚C/23˚C及29˚C/26˚C栽培綠豆芽，VC6089A在29˚C/23˚C 及26˚C/26˚C栽培之鮮重較佳，VC1973A與日正綠豆則分別於29˚C/23˚C與26˚C/26˚C之鮮重較佳；綠豆芽之可溶性固形物及可溶性蛋白質含量顯著受栽培溫度組合之影響；而VC1973A綠豆芽之總類黃酮及總酚類含量皆較其他兩綠豆芽高。相較於0、10、20與50 mM氯化鈉溶液，以15 mM氯化鈉溶液栽培綠豆芽時，其產量較高、總類黃酮及總酚類含量最高，且VC1973A綠豆芽之亞鐵離子螯合能力(Fe2+ chelating ability)較高；氯化鈉試驗中，綠豆芽鮮重分別與可溶性糖含量 (r=0.83***) 、總類黃酮含量 (r=0.84***) 、總酚類含量 (r=0.85***) 及DPPH自由基清除能力 (r=0.85***) 皆呈高度正相關，而總酚類與總類黃酮含量或可作為DPPH自由基清除能力及FRAP鐵離子氧化還原能力之參考指標。以0、10、25、50、75及100 mM葡萄糖溶液栽培綠豆芽，50 mM組之抗壞血酸及總類黃酮含量較高，100 mM組含有較多的可溶性固形物及可溶性蛋白質。綜之，VC1973A綠豆芽之鮮重、外觀及植化素含量皆優於以VC6089A及日正綠豆栽培之綠豆芽。故建議於全黑暗環境下，以種子密度7 g·cm-2、壓重400 g·51.84 cm-2、15 mM氯化鈉溶液及29˚C 16 h /23˚C 8 h，栽培VC1973A綠豆芽3天，可獲得總類黃酮 (0.38 mg·g-1DW) 及總酚類含量 (11.1 mg·g-1DW) 、亞鐵離子螯合能力 (84.8 % of 50 mg DW·mL-1) 、DPPH自由基清除能力 (54.1 % of 50 mg DW·mL-1)與FRAP鐵離子氧化還原能力 (150.9 µmol FeSO4·g-1DW) 最高、且產量 (54.5 g FW·51.84 cm-2) 亦佳之綠豆芽。

BackgroundThe use of pomegranate peel is highly associated with its rich phenolic concentration. Series of drying methods are recommended since bioactive compounds are highly sensitive to thermal degradation. The study was conducted to evaluate the effects of drying on the bioactive compounds, antioxidant as well as antibacterial and antityrosinase activities of pomegranate peel.MethodsDried pomegranate peels with the initial moisture content of 70.30 % wet basis were prepared by freeze and oven drying at 40, 50 and 60 °C. Difference in CIE-LAB, chroma (C*) and hue angle (h°) were determined using colorimeter. Individual polyphenol retention was determined using LC-MS and LC-MSE while total phenolics concentration (TPC), total flavonoid concentration (TFC), total tannins concentration (TTC) and vitamin C concentration were measured using colorimetric methods. The antioxidant activity was measured by radical scavenging activity (RSA) and ferric reducing antioxidant power (FRAP). Furthermore, the antibacterial activity of methanolic peel extracts were tested on Gram negative (Escherichia coli and Klebsiella pneumonia) and Gram positive bacteria (Staphylococcus aureus and Bacillus subtilis) using the in vitro microdilution assays. Tyrosinase enzyme inhibition was investigated against monophenolase (tyrosine) and diphenolase (DOPA), with arbutin as positive controls.ResultsOven drying at 60 °C resulted in high punicalin concentration (888.04 ± 141.03 mg CE/kg dried matter) along with poor red coloration (high hue angle). Freeze dried peel contained higher catechin concentration (674.51 mg/kg drying matter) + catechin and –epicatechin (70.56 mg/kg drying matter) compared to oven dried peel. Furthermore, freeze dried peel had the highest total phenolic, tannin and flavonoid concentrations compared to oven dried peel over the temperature range studied. High concentration of vitamin C (31.19 μg AAE/g dried matter) was observed in the oven dried (40 °C) pomegranate peel. Drying at 50 °C showed the highest inhibitory activity with the MIC values of 0.10 mg/ml against Gram positive (Staphylococcus aureus and Bacillus subtili. Likewise, the extracts dried at 50 °C showed potent inhibitory activity concentration (22.95 mg/ml) against monophenolase. Principal component analysis showed that the peel colour characteristics and bioactive compounds isolated the investigated drying method.ConclusionsThe freeze and oven dried peel extracts exhibited a significant antibacterial and antioxidant activities. The freeze drying method had higher total phenolic, tannin and flavonoid concentration therefore can be explored as a feasible method for processing pomegranate peel to ensure retention of the maximum amount of their naturally occurring bioactive compounds.Trial registrationNot relevant for this study.

Eight selected wild vegetables from Nepal (Alternanthera sessilis, Basella alba, Cassia tora, Digera muricata, Ipomoea aquatica, Leucas cephalotes, Portulaca oleracea and Solanum nigrum) were investigated for their antioxidative potential using 2,2-dyphenyl-1-picrylhydrazyl (DPPH) scavenging, hydrogen peroxide (H2O2), ferric reducing antioxidant power (FRAP), and ferric thiocyanate (FTC) methods. Among the selected plant extracts C. tora displayed the highest DPPH radical scavenging activity with an IC50 value 9.898 μg/mL, whereas A. sessilis had the maximum H2O2 scavenging activity with an IC50 value 16.25 μg/mL—very close to that of ascorbic acid (16.26 μg/mL). C. tora showed the highest absorbance in the FRAP assay and the lowest lipid peroxidation in the FTC assay. A methanol extract of A. sessilis resulted in the greatest phenolic content (292.65 ± 0.42 mg gallic acid equivalent (GAE)/g) measured by the Folin–Ciocalteu reagent method, while the smallest content was recorded for B. alba (72.66 ± 0.46 GAE/g). The greatest flavonoid content was observed with extracts of P. oleracea (39.38 ± 0.57 mg quercetin equivalents (QE)/g) as measured by an aluminium chloride colorimetric method, while the least was recorded for I. aquatica (6.61 ± 0.42 QE/g). There was a strong correlation between antioxidant activity with total phenolic (DPPH, R2 = 0.75; H2O2, R2 = 0.71) and total flavonoid content (DPPH, R2 = 0.84; H2O2, R2 = 0.66). This study demonstrates that these wild edible leafy plants could be a potential source of natural antioxidants.

Two underutilized indigenous fruits of Borneo, Liposu (Baccaurea lanceolata) and Tampoi (Baccaurea macrocarpa) were investigated for their total phenolic (TPC), flavonoid (TFC), anthocyanin (TAC) and carotenoid (TCC) contents as well as antioxidant properties in vitro. The fruits were separated into three different parts (i.e., pericarp, flesh and seed) and extracted using 80% methanol. Antioxidant activity was determined using DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging, ABTS decolorization and FRAP (Ferric Reducing Antioxidant Power) assays. The results showed that B. macrocarpa pericarp contained the highest amount of total phenolics, total flavonoid, total anthocyanin and total carotenoid with the values of 60.04 ± 0.53 mg GAE/g, 44.68 ± 0.67 mg CE/g, 1.23 ± 0.20 mg c-3-gE/100 g and 0.81 ± 0.14 mg BCE/g. Results from DPPH, ABTS and FRAP assays also showed that the pericarp of B. macrocarpa displayed the highest antioxidant capacity. The antioxidant activity of the extract was significantly correlated with the total phenolic and flavonoid contents, but not with the carotenoid contents. In conclusion, B. macrocarpa displayed high potential as natural source of phytochemicals with antioxidant properties.

Antioxidant potential of two varieties of Sesamum indicum L. collected from Indonesia.

The effect of extraction time on the color, total flavonoid content (TFC), total phenolic content (TPC), and antioxidant activity of the polyherbal drink consisted of 10% turmeric (Curcuma longa L.), 20% Java tea (Orthosiphon aristatus (Blume) Miq.), and 70% seed-under-leaf (Phyllanthus niruri L.) crude drugs were evaluated in this study. The drinks were prepared by decoction at various extraction times. The drink color was read by LAB colorimetry. TPC and TFC were determined by the official methods in the Indonesian Herbal Pharmacopeia (IHP). The antioxidant activity was evaluated by the standard 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. The color of the extracts obtained from different extraction times was statistically equal in L*, a*, and b* of color parameters. The TPC, TFC, DPPH radical scavenging activity, and FRAP of the extracts were considerably increased during the first 15 mins of extraction. The TPC value started to decrease after being extracted for 45 mins. The value of TFC, DPPH radical scavenging activity, and FRAP of the drinks remained unchanged until the final extraction time. Thus, the recommended extraction time of the polyherbal drink was 15 mins to preserve the phenolic compounds and flavonoids and obtain optimum antioxidant activity.

Aim: Many diseases are associated with oxidative stress caused by free radicals. The present research was carried out to evaluate the total phenolic contents, flavonoid contents and in vitro evaluation of antioxidant potentials by five different assay method of various (benzene, chloroform, acetone, and ethanol) extracts of leaves and stems of Kalanchoe pinnatum as the plant is an ingredient of various traditional preparations used in the treatment of various diseases. Materials and Methods: Antioxidant and free radical scavenging activity was determined by using five different in vitro antioxidant assays including 2, 2‑Diphenyl‑1‑Picrylhydrazyl (DPPH), hydrogen peroxide, nitric oxide, ferric reducing antioxidant power and phosphomolybdenum assays. In the present investigation, quantitative estimation of flavonoid content and phenolic content was carried out by colorimetric methods using aluminium chloride and Folin‑Ciocalteu reagent methods respectively to establish relationship between antioxidant activity and total phenolic and flavonoid contents. Results and Conclusions: The plant powder (100 mg) yielded 0.49, 0.64, 0.99, 1.17 %w/w total phenolic content in leaves and 0.18, 0.27, 0.48, 0.62 %w/w total phenolic content in the benzene, chloroform, acetone, ethanol extracts of stems respectively using gallic acid as standard and plant contains about 0.24, 0.37, 0.56, 0.75 %w/w of total flavonoids content in leaves and 0.15, 0.22, 0.42, 0.54 %w/w of total flavonoids content in the benzene, chloroform, acetone, ethanol extracts of stems respectively using quercetin as standard. The extracts showed significant antioxidant activity in dose dependent manner in all the assays. The result obtained in the present study indicated that leaves and stems of K. pinnatum could be a potential source of natural antioxidant and justified the traditional use of herb in preventing disease induced by oxidative stress. Key words: DPPH scavenging activity, Kalanchoe pinnatum, no scavenging activity, phytochemical screening

Medicinal plants have been used for therapeutic purposes and have shown important biological properties. This study aimed to evaluate for the first time the antioxidant activities, total flavonoid, and total phenolic contents of Lavandula mairei Humbert. The ethanol, methanol, ethyl-acetate, and water extracts were used for this purpose. The antioxidant activities were assessed in vitro by free radical scavenging activity against 2,2-diphenyl-1-picrylhydrzyl (DPPH), ferric reducing antioxidant power (FRAP), and total antioxidant capacity (TAC). The total flavonoid and phenolic contents were determined spectrophotometrically with gallic acid and Quercetin as standards. In either Soxhlet or maceration methods, the flavonoids and the total phenolic contents were significantly higher in the methanolic extract (P<0.05) compared to other extracts. The total flavonoid content of L. mairei ranged between 119 and 224.6 mg QE/g DW for Soxhlet extracts and from 111.8 to 148.51 mg QE/g DW for maceration extracts. While the total phenolic content was between 35.12 and 99.37 mg GAE/g DW for Soxhlet extracts and 27.63 to 58.99 mg GAE/g DW for maceration extracts. In either the Soxhlet or maceration method, the highest total antioxidant capacity (TAC) was obtained using the ethanolic extract, while the aqueous extract had the highest antioxidant activity for DPPH and FRAP assays. These results showed that Lavandula mairei Humbert has great potential to be a promising candidate for natural plant sources of antioxidants.

Black rice (Oryza sativa L.) is a rich source of phenolics and anthocyanins. It was aimed to investigate the effect of different extraction methods such as conventional solvent extraction, ultrasound-assisted extraction (UAE), and microwave-assisted extraction (MAE) on antioxidant activity and phenolic profiling of black rice free, esterified, and bound phenolics fractions. Spectrophotometric methods were used to evaluate antioxidant activity and HPTLC was used for phenolics profiling. The highest content of % yield, total anthocyanin (TAC), total phenolic (TPC), and total flavonoid (TFC) contents were detected in MAE. It was also observed that antioxidant activity based on DPPH, ABTS, superoxide radical-scavenging and ferric reducing antioxidant power (FRAP) assays showed highest activity in MAE. Eight phenolic compounds were identified and quantified by a validated HPTLC method. MAE showed most abundant phenolic compounds. A significant positive correlation was established between % yield, total phenolic content, and total flavonoid content (p<0.05) where a significant negative correlation was established between % yield, TPC, and TFC with IC50 of antioxidant activity (p<0.05). Diverse phenolic contents and antioxidant activity were studied with different forms of phenolics with the different extraction methods. It designates that the extraction techniques had effects on the bioactive compounds as well biological properties.