Biological activity and composition of extract from aerial root of Ficus microcarpa L. fil.

Total phenolic content, antioxidant and antibacterial activities of Ficus microcarpa aerial roots were determined on methanol extract and its sub-fractions (hexane, ethyl acetate, n -butanol and water). The ethyl acetate fraction possessed the highest amount of phenolic compounds evaluated by Folin-Ciocalteu reagent method. It also showed the highest antioxidant activity when tested the following methods: DPPH, ABTS⁺ radical-scavenging, superoxide radical scavenging, reducing power and β -carotene linoleic acid bleaching. On the other hand, high phenolics content extracts (ethyl acetate, methanol and n -butanol) showed significantly higher inhibitory activity than low phenolics content extracts (water and hexane) against five tested Gram positive and Gram negative bacteria. Protocatechuic acid, catechol, p -vinylguaiacol, syringol, p -propylphenol, vanillin, p -propylguaiacol, isovanillic acid, 4- n -Propylresorcinol, syringaldehyde and oleanolic acid contained in ethyl acetate fraction were identified by GC-MS and HPLC based on their cochromatography with standard compounds. Protocatechuic acid, catechol and syringol exhibited nearly same antioxidant activity as did by positive control Trolox using the mentioned assays. Results here showed that the ethyl acetate fraction has strong antioxidant and antibacterial activities, which are correlated with its high level of phenolic compounds.     

In Vitro Antioxidant and Antiglycation Properties of Methanol Extract and Its Different Solvent Fractions of Musa paradisiaca L. (Cv. Nendran) Inflorescence

Methanolic extract of Musa paradisiaca inflorescence and its different solvent fractions, petroleum ether, ethyl acetate, butanol, and water were studied for their total phenolic and flavonoid content, free radical scavenging, and antiglycation activities, and these properties were compared with standard antioxidant compounds. Ethyl acetate fraction exhibited higher antioxidant and antiglycation properties than other fractions. IC₅₀ values of ethyl acetate fraction for 1,1-diphenyl-2-picrylhydrazyl method, 2,2-azinobis-3 ethylbenzothiazoline-6-sulphonic acid method, superoxide radical scavenging, hydroxyl radical scavenging, nitric oxide radical scavenging, and antiglycation activities were 9.80, 13.50, 26.40, 19.71, 25.73, and 31.00 μ g/ml, respectively. Total phenolic content of ethyl acetate (21.52 mg GAE/g) was significantly higher than other fractions. There was positive linear correlation between antioxidant activity and total phenolic content.      

Antioxidant activity and chemical constituents of essential oil and extracts of Rhizoma Homalomenae

Antioxidant activity and composition of essential oil and extracts of Rhizoma Homalomenae were determined. The extracts, especially the ethyl acetate extract (QJ4 fraction) of the aqueous residue after oil distillation, had considerable antioxidant potency which was significantly associated with their total phenolic and flavonoid contents, but the essential oil showed only weak or moderate activity. GC–MS analysis of the essential oil (yield: 0.82%, v/w) resulted in the identification of 77 compounds, accounting for 96.5% of the content of the oil. The major components, epi-α-cadinol (14.8%), α-cadinol (14.8%), α-terpineol (13.8%), linalool (11.1%), terpinen-4-ol (4.92%), and δ-cadinene (4.91%) constituted 64.3% of it. LC–MS/MS and HPLC analyses showed seven phenolic compounds (protocatechuic acid, vanillic acid, syringic acid, caffeic acid, p-coumaric acid, ferulic acid and apigenin) with a great amount in the ethyl acetate extract (QJ4 fraction). The strong antioxidant properties of the plant extracts may be attributed to the presence of these phenolics.     

Studies on the antioxidant potential of flavones of Allium vineale isolated from its water-soluble fraction

The aim of this work was to examine the chemical constituents and antioxidant potential of water-soluble fractions from the commonly consumed vegetable, Allium vineale. The water-soluble fraction, containing phenolic compounds, was extracted with ethyl acetate to obtain flavonoids which were separated and purified by repeated column chromatography over Sephadex LH-20, RP C18 and silica gel. The isolated compounds were identified according to their physicochemical properties and spectral data (UV, HPLC–TOF/MS, ¹H NMR, ¹³C NMR and 2D NMR). Three flavonoids were isolated and identified as chrysoeriol-7-O-[2″-O-E-feruloyl]-β-d-glucoside (1), chrysoeriol (2), and isorhamnetin-3-β-d-glucoside (3). Antioxidant studies of the aqueous extract and three isolated compounds, 1, 2, 3, were undertaken and they were found to have significant antioxidant activity. Antioxidant activities were evaluated for total antioxidant activity by the ferric thiocyanate method, ferric ion (Fe³⁺) reducing antioxidant power assay (FRAP), ferrous ion (Fe²⁺) metal chelating activity, and DPPH free radical-scavenging activity. The water-soluble ethyl acetate and methanol extraction methods were also compared using HPLC–TOF/MS.     

In vitro antioxidant activities of three selected brown seaweeds of India

In vitro antioxidant activities of three selected Indian brown seaweeds – viz., Sargassum marginatum, Padina tetrastomatica and Turbinaria conoides – were investigated. Total phenolic content and reducing power of crude methanolic extract were also investigated. The activity of total methanolic extract and five different fractions (viz., petroleum ether (PE), ethyl acetate (EA), dichloromethane (DCM), butanol (BuOH) and aqueous) were studied using total antioxidant activity, DPPH radical scavenging and deoxyribose assays. EA fraction of S. marginatum exhibited higher total antioxidant activity of 39.62 mg ascorbic acid equivalent/g extract (or 0.31 mg ascorbic acid equivalent/g seaweed on dry weight basis) among the all the fractions. Among the fractions obtained from different seaweeds, EA fraction of S. marginatum showed higher DPPH scavenging activity of 23.16%; while PE fraction of T. conoides exhibited lower deoxyribose activity of 47.81%. Higher phenolic content (49.16 mg gallic acid equivalent/g extract or 0.86 mg GAE/g of seaweed on dry weight basis) was noticed in aqueous fraction of T. conoides. Reducing power of crude methanolic extract increased with increasing concentration. Reducing power of T. conoides and P. tetrastomatica were higher compared to standard antioxidant (α-tocopherol). Among the seaweeds, total methanolic extract of T. conoides had significantly higher phenol content (P < 0.05) compared to the other two species. In vitro antioxidant activity of methanolic extracts from all the three seaweeds showed an increase with increasing concentration indicating the dose dependency of these properties.     

Antioxidant activity of the phenolic compounds released by hydrothermal treatments of olive tree pruning

The liquors from liquid hot water treatment (LHW) and from steam explosion (SE) of Olea europea pruning were characterised for phenolic content and in vitro antioxidant activity. Rising the temperature treatment enhanced the release of phenolic compounds to the aqueous phase and the fraction of them which are soluble in ethyl acetate was increased. Up to 2.29 and 1.88 g gallic acid equivalents (GAE)/100 g pruning were solubilised in LHW and SE, respectively, 80% of these compounds were recovered in the ethyl acetate extract. Syringol and syringaldehyde were the most abundant lignin derived volatile products identified. Hydroxytyrosol, oleuropein, syringaldehyde and tyrosol were the major phenolic compounds identified by HPLC. The antioxidant activity of the extracts, comparable to that of synthetic antioxidants, depended on the extract concentration but was scarcely affected by treatment temperature.     

The antioxidant, angiotensin converting enzyme inhibition activity, and phenolic compounds of bamboo shoot extracts

This study was undertaken to evaluate the functional properties of two of the most popular species of edible bamboo shoots in Korea (Phyllostachys pubescens and Phyllostachys nigra). Powdered bamboo shoots were extracted with methanol and an aqueous suspension of the obtained methanol extract was partitioned successively with chloroform, ethyl acetate, and butanol, leaving a residual water extract. All obtained extracts were evaluated for their antioxidant capacity and antimicrobial activity, angiotensin converting enzyme (ACE) inhibition activity, and ascorbic acid and phenolic compound content. Methanol and water fractions showed a particularly high ascorbic acid contents. The ethyl acetate fraction contained a high concentration of phenolic compounds. Among all extracts, the ethyl acetate and butanol fractions showed particularly high antioxidant activity. Methanol extract had a significantly higher ACE inhibitory activity than other extracts. None of the extracts inhibited the tested bacteria.     

龙眼核多酚物质的液质联用分析及其抗氧化活性

为研究龙眼核抗氧化能力与成分的关系,采用不同极性溶剂萃取分离法、HPLC-ESI-MS分析法和DPPH抗氧化能力测定法等对60%乙醇提取的龙眼核多酚粗提物进行分析研究,鉴定出11种物质,其中6种为多酚,确定乙酸乙酯相抗氧化活性最强;进一步对经大孔树脂AB-8柱分离后的乙酸乙酯相各流份进行体外DPPH自由基清除能力和还原能力测定,得知与抗坏血酸相比,流份Fr1～Fr16都具有良好的抗氧化活性,其中流份Fr7、Fr8抗氧化活性最强。结合化学分离结果分析,流份Fr7经反复重结晶,得到较纯的没食子酸,其抗氧化能力较强,与抗氧化分析实验结果相一致。低极性萃取相抗氧化能力最强也表明龙眼核中含有丰富的小分子多酚类物质。     

Antioxidant and cytotoxic activities of various fractions of ethanol extract of Dianthus superbus

This study examined the antioxidant and cytotoxic activities of various fractions (prepared by using solvents of varying polarity) of ethanol extract of Dianthus superbus (DS). The antioxidant activities of various fractions were evaluated in terms of their free radical-scavenging activity. The total phenolics and reducing powers of the fractions were measured. The cytotoxic activities of the fractions on three human malignant cell lines were also investigated. Among all fractions, the ethyl acetate fraction (EE-DS), which had the highest phenolic content and the strongest reducing power, exhibited the strongest antioxidant and cytotoxic activities.     

Antibacterial Constituents of Hainan Morinda citrifolia (Noni) Leaves

Noni (Morinda citrifolia L.) is an edible and medicinal plant distributed in Hainan, China. The antibacterial activities of the extracts of water (WE), petroleum ether (PEE), ethyl acetate (EAE), chloroform (CE), and n‐butanol (BE) were assayed by the disk diffusion method. The results showed that the extracts from Noni leaves possessed antibacterial effects against Bacillus subtilis, Escherichia coli, Proteus vulgaris, and Staphylococcus aureus. Among 5 different extracts, the BE produced the best antibacterial activity. The samples were first extracted by ethanol, and the primary compounds in the BE fraction of ethanol extract was further isolated and identified. Six phenolic compounds, including 5, 15‐dimethylmorindol, ferulic acid, p‐hydroxycinamic acid, methyl 4‐hydroxybenzoate, methyl ferulate, and methyl 4‐hydroxycinnamate, were identifiedby NMR. The results indicated that the phenolic compounds might significantly contribute to antibacterial activities of Noni leaves.     

HPLC–MS analyses and bioactivities of novel chemicals in Devil’s club (Oplopanax horridus (Sm.) Miq.)

Devil’s club (Oplopanax horridus (Sm.) Miq.) has traditionally been used as a folk medicine by native North Americans for the treatment of various chronic diseases. A methanolic extract and its sub-fractions by liquid–liquid re-extraction, i.e., chloroform (CHCl₃), ethyl acetate (EtOAc), n-butanol (BuOH), and water fractions, were analysed by their anti-cancer activity with in vitro cell proliferative bioassays, and their antioxidant capacities in terms of the determination of total phenolic content (TPC), ORAC value, and DPPH free radical scavenging activity. The whole extract of the dried root contained high TPC and possessed strong ORAC and DPPH radical scavenging activities. In addition, the extract exhibited a strong anti-proliferative ability against HT-29 cancer cells, e.g., with an inhibitive rate of 56.5% with a 0.2-mg/mL extract. Further investigation by HPLC–UV–MS identified significant bioactive phenolic compounds in the chloroform fraction, including gallic acid, caffeic acid, 4-O-feruloylquinic acid, 5-O-feruloylquinic acid, ferulic acid, methyl feruloylquinate, methyl ferulate, and quercetin. These results suggested that the associated bioactivity of the plant might result from the contribution of phenolic compounds.     

Antioxidant activities of phenolic rich fractions (PRFs) obtained from black mahlab (Monechma ciliatum) and white mahlab (Prunus mahaleb) seedcakes

The antioxidant activities of phenolic rich fractions (PRFs) from crude methanolic extract (CME), and its fractions using ethyl acetate (EAF), hexane (HF) and water (WF) of black mahlab (Monechma ciliatum) and white mahlab (Prunus mahaleb) seedcakes were investigated. The total phenolic compounds were found to be higher in white mahlab than black mahlab seedcakes. The antioxidant activity determined by the DPPH method revealed that black mahlab PRFs had the highest antioxidant activity, compared to white mahlab fractions. The presence of antioxidants in the two mahlab PRFs reduced the oxidation of β-carotene by hydroperoxides from these extracts/fractions. The effect of the two mahlab PRFs on the oxidative stability of corn oil at 70 °C was tested in the dark and compared with butylated hydroxyanisole (BHA). The CME performed better antioxidant activity in inhibiting the formation of both primary and secondary oxidation products. The qualitative and quantitative characterisation of phenolic compounds was carried out by HPLC/DAD.     

新疆野生樱桃李枝、叶不同萃取部位抗氧化活性研究

采用系统溶剂萃取野生樱桃李枝、叶甲醇提取物,分别得到其石油醚相、乙酸乙酯相、正丁醇相,采用分光光度法测定其总酚含量,并通过清除DPPH自由基能力、还原能力、总抗氧化能力等化学模型对各部位的抗氧化活性进行测定。结果表明,野生樱桃李枝、叶提取物抗氧化活性与其总酚含量呈正相关性,提示酚类化合物为影响其抗氧化活性的主要因素。在三种抗氧化模型下,枝、叶各萃取相均表现一定的抗氧化活性,且具有相似的抗氧化活性规律:乙酸乙酯相>正丁醇相>石油醚相,说明乙酸乙酯和正丁醇可以有效地富集野生樱桃李枝、叶抗氧化成分,其中树枝乙酸乙酯相抗氧化活性著高于BHA。说明野生樱桃李枝、叶提取物具有作为天然抗氧化剂的开发价值。      

Major chemical constituents and antioxidant activities of different extracts from the peduncles of Hovenia acerba Lindl

Hovenia acerba Lindl. is a perennial tree of Rhamnaceae family. In the present study, four solvents (80% methanol, ethyl acetate, n-hexane, and water) were used to extract the compounds of Hovenia acerba Lindl. peduncles (HAP). The total contents of phenolics and tannins (TPC and TTC), as well as their antioxidant activities (DPPH, ABTS, and FRAP) of these four different extracts including 80% methanol extract (ME), ethyl acetate extract (EE), n-hexane extract (HE) and water extract (WE) were compared. The antioxidant activities of HAP showed positive correlations with TPC and TTC, indicating that phenolics maybe a major contributor to the antioxidant activities of HAP. The significant difference between antioxidant activities and TPC/TTC implied the respective contribution extent of phenolics for the antioxidant activities of four solvent extracts. Besides, a total of 117 compounds, including 7 oligosaccharides, 11 organic acids, 41 phenolics, 1 steroids, 25 terpenes, 11 fatty acids, 9 amino acids, and 12 other compounds were identified or tentatively characterized in HAP for the first time. Among them, 23 bioactive constituents, including 4 organic acids, 5 phenolic acids, and 14 flavonoids, were quantified. The comparison of characterization and quantitation of 4 extracts demonstrated that 80% methanol showed the widest range of selectivity for both HAP flavonoid aglycones and glycosides, while ethyl acetate preferred to extract the flavonoids aglycone from HAP. Secondly, water and 80% methanol were excellent solvents for the extraction of phenolic acids. And both ethyl acetate and 80% methanol perform well at the extraction of terpenes and steroids.     

Isolation and Identification of Phenolic Antioxidants in Black Rice Bran

Black rice bran contains phenolic compounds of a high antioxidant activity. In this study, the 40% acetone extract of black rice bran was sequentially fractionated to obtain 5 fractions. Out of the 5 fractions, ethyl acetate fraction was subfractionated using the Sephadex LH‐20 chromatography. The antioxidant activity of phenolic compounds in the extracts was investigated by 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical assay, 2,2‐azino‐bis‐(3‐ethylenebenzothiozoline‐6‐sulfonic acid) (ABTS) radical cation assay, reducing power. The subfraction 2 from ethyl acetate fraction had the highest total phenolic contents (TPC) (816.0 μg/mg) and the lowest EC₅₀ values (47.8 μg/mL for DPPH radical assay, 112.8 μg/mL for ABTS radical cation assay, and 49.2 μg/mL for reducing power). These results were 3.1, 1.3, and 2.6 times lower than those of butylated hydroxytoluene (BHT), respectively. At a concentration of 100 μg/mL, the antioxidant activity and TPC of various extracts was closely correlated, with correlation coefficients (R²) higher than 0.86. The major phenolic acid in subfraction 2 was identified as ferulic acid (178.3 μg/mg) by HPLC and LC‐ESI/MS/MS analyses. Our finding identified ferulic acid as a major phenolic compound in black rice bran, and supports the potential use of black rice bran as a natural source of antioxidant.     

Radical scavenging and reducing properties of extracts of cashew shoots (Anacardium occidentale)

The total phenolic content and antioxidant activities of methanol, hexane and ethyl acetate extracts of the shoots of Anacardium occidentale were measured. Total phenolic content was assessed by the Folin–Ciocalteau assay whereas antioxidant activities were assessed by measuring the ability of the extracts to scavenge the ABTS^·+ and DPPH^· radicals, superoxide anion radicals and nitric oxide radicals as well as their ability to reduce ferric ions. Results indicated that the methanol extract of A. occidentale was the most potent reducing agent and radical-scavengers compared to the other two extracts. The ethyl acetate extract exhibited some antioxidant activities whereas the hexane extract is the least reactive. The order of the antioxidant potency of the plant extract is methanol > ethyl acetate > hexane. The methanol extract contained more than 7 fold of total phenolic content compared to the hexane and ethyl acetate extracts indicating the likely possibility that the observed antioxidant activities were partly contributed by the phenolics. The results suggest that the shoots of A. occidentale are a source of natural antioxidants.     

Study on antioxidant activity of certain plants in Thailand: Mechanism of antioxidant action of guava leaf extract

The ethanol extracts from 24 samples plant species commonly found in Thailand were investigated and compared on their antioxidant activity by ABTS assay. The ethanol extract from the leaves of guava (Psidium guajava) showed the highest antioxidant capacity with the TEAC value of 4.908 ± 0.050 mM/mg, followed by the fruit peels of rambutan (Nephelium lappaceum) and mangosteen (Garcinia mangostana) with the TEAC values of 3.074 ± 0.003 and 3.001 ± 0.016 mM/mg, respectively. The further investigation of guava leaf extracts from different solvents; n-hexane, ethyl acetate, n-butanol, and methanol, was examined using ABTS and FRAP assays. The total phenolic content was done by Folin–Ciocalteu reaction. The results indicated that the methanol fraction possessed the highest antioxidant activity, followed by the butanol and ethyl acetate fractions, respectively. The hexane fraction showed the lowest antioxidant activity. The results demonstrated that the mechanism of antioxidant action of guava leaf extracts was free radical scavenging and reducing of oxidized intermediates. The phenolic content in guava leaf fraction played a significant role on the antioxidant activity via reducing mechanisms.     

Chemical composition and antioxidant activity of Korean cactus (Opuntia humifusa) fruit

The chemical composition and antioxidant activities of the Korean cactus (Opuntia humifusa, OH) fruit were investigated in this study. Major minerals in the OH fruit were P, Ca, and Mg. Total dietary fiber content was 22.8% and the soluble dietary fiber/insoluble dietary fiber ratio was 1:1.3. An 80% ethanol extract was used to investigate antioxidant activities based on DPPH radical scavenging ability as well as total phenolic and flavonoid content. OH fruit extract from 80% ethanol was sequentially fractionated according to the polarity of solvents. Among various fractions, the ethyl acetate fraction showed the highest antioxidant activity as well as the highest total phenolic and total flavonoid contents compared to other fractions. The most abundant phenolic acid in the ethyl acetate fraction was ferulic acid, followed by protocatechuic acid. The most abundant flavonoid was taxifolin, followed by myricetin. The results suggested that OH fruit could be a good potential source of antioxidant.     

In vitro synergistic anti-oxidant activities of solvent-extracted fractions from Astragalus membranaceus and Glycyrrhiza uralensis

Our study estimated the in vitro anti-oxidant activities of the solvent-extracted fractions from Astragalus membranaceus (AME), Glycyrrhiza uralensis (GU) and the combination of them (AG), using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, 2,2-azinobis (3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) free radical scavenging assay and ferric reducing anti-oxidant power (FRAP) assay. Different solvent extracts have different anti-oxidant activities. As to the herb pair (AG), the highest anti-oxidant capacity and total phenolic/flavonoid content were observed in the ethyl acetate fraction, which were exhibited in different solvent fractions of the individual herbs. The ethyl acetate extract of herb pair (EA-AG) showed significantly higher anti-oxidant capacity than the theoretical sum of two single herbs, and presented better cytoprotection and induced higher activity of anti-oxidant enzymes than the single herbs. Moreover, there’s a linear correlation between the increment of total phenolics/flavonoids and anti-oxidant capacities, especially between polyphenol content and TEAC values (correlation coefficient = 0.9^∗). These indicated that the phenolic and flavonoid may be the main compounds which caused the synergistic anti-oxidant capacity and cytoprotection in the combination of AME and GU.