Dereplication coupled with in vitro antioxidant assay of two flavonoid glycosides from Diospyros peregrina fruit

Diospyros peregrina is an edible seasonal fruit found in coastal West Bengal, India. The fruits have been reported to possess a significant antioxidant activity. In this study, the aim was to isolate the lead compound responsible for the above-mentioned activity. The aqueous extract of D. peregrina fruit was subjected to dereplication coupled with an in?vitro 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging assay. The n-butanol fraction of the aqueous extract of D. peregrina fruit exhibited significant antioxidant activity (IC(50), 131.10?μg?mL(-1)) as compared with the parent extract (IC(50), 285.15?μg?mL(-1)). The n-butanol fraction was subjected to silica gel column chromatographic separation coupled with a chemo-autographic study of column eluents, employing ethanolic DPPH as a spraying reagent. Two bioactive flavonoid glycosides, namely luteoline-4'-methyl-ether-7-O-glucoside and quercetin-3-O-(glucosyl)-glucoside, were identified to exhibit IC(50) values of 74.04 and 65.78?μg?mL(-1), respectively in the DPPH assay.     

Free radical scavenging, antimicrobial and immunomodulatory activities of Orthosiphon stamineus

Orthosiphon stamineus is considered an important traditional folk medicine. In this study ethanol and aqueous extracts of O. stamineus were evaluated in vitro for their antioxidant, antimicrobial as well as for their immunomodulatory properties on human peripheral blood mononuclear cells (PBMCs). The DPPH radical scavenging method was used for the determination of antioxidant activity, while the antibacterial efficacy was investigated by both disc diffusion method and Minimum Inhibitory Concentration (MIC) against four bacterial strains (Gram-positive and Gram-negative). Furthermore, the immunomodulatory potential of the extracts was investigated through the MTT assay. Aqueous extract of O. stamineus exhibited significant free radical scavenging activity with IC?? 50 9.6 μg/mL, whereas the IC?? for the ethanol extract was 21.4 μg/mL. The best antimicrobial activity was shown by the aqueous extract of O. stamineus against Staphylococcus aureus, with inhibition zone of 10.5 mm and MIC value 1.56 mg/mL. Moreover, the results observed from the MTT assay showed that both plant extracts stimulated the PBMCs proliferation in vitro in a concentration-dependent manner, but the aqueous extract has remarkable activity against PBMCs. These findings indicate that O. stamineus showed high antioxidant activity and may be considered as an immunomodulatory agent.     

Turmerin, the antioxidant protein from turmeric (Curcuma longa) exhibits antihyperglycaemic effects

A wide range of proteinaceous inhibitors are present in plants to protect themselves from hydrolytic enzymes. In this study, turmerin, a water-soluble peptide in turmeric rhizomes, was evaluated for its inhibitory potential against glucosidase and its antioxidant (AO) capacity. Turmerin inhibited α-amylase and α-glucosidase activities with IC?? values 31 and 192?μg?mL?1, respectively. Under the experimental conditions, those values for a standard glucosidase inhibitor, acarbose, were 81 and 296?μg?mL?1, respectively. The AO capacity of turmerin was evaluated using in vitro assay systems. Turmerin showed good DPPH (IC???=?29?μg?mL?1) and superoxide (IC???=?48?μg?mL?1) and moderate ABTS (IC???=?83?μg?mL?1) radical scavenging and Fe(II) chelation (IC???=?101?μg?mL?1) capacities. The inhibitory potential showed by turmerin against enzymes linked to type 2 diabetes, as well as its moderate AO capacity, could rationalise the traditional usage of turmeric rhizome preparations against diabetes.     

In vitro inhibitory effects of cyandin-3-rutinoside on pancreatic α-amylase and its combined effect with acarbose

The inhibitory activity on pancreatic α-amylase by cyanidin-3-rutinoside was examined in vitro. The IC?? value of cyanidin-3-rutinoside against pancreatic α-amylase was 24.4 ± 0.1 μM. The kinetic analysis revealed that pancreatic α-amylase was inhibited by cyanidin-3-rutinoside in a non-competitive manner. The additive inhibition of a combination of cyanidin-3-rutinoside with acarbose against pancreatic α-amylase was also found. These results provide the first evidence for the effect of cyanidin-3-rutinoside in a retarded absorption of carbohydrates by inhibition of pancreatic α-amylase which may be useful as a potential inhibitor for prevention and treatment of diabetes mellitus.     

Ethanolic extract of Rubia peregrina L. (Rubiaceae) inhibits haloperidol-induced catalepsy and reserpine-induced orofacial dyskinesia

In the traditional Sardinian system of medicine, Rubia peregrina L. (Rubiaceae) is reported as an aphrodisiac herb. Since the aphrodisiacs may also have antioxidant and dopaminergic activities, the aim of this study was to study the effect of ethanolic extract of aerial parts of R. peregrina for the scavenging of free DPPH radicals and the inhibition of haloperidol-induced catalepsy in mice and reserpine-induced orofacial dyskinesia in rats. The extract exhibited significant antioxidant activity in a free radical DPPH assay with IC(50)?=?55.6?μg?mL(-1), which was very close to IC(50) of ascorbic acid. The extract of R. peregrina (100 and 200?mg?kg(-1) intraperitoneally, i.p.) significantly inhibited haloperidol (1?mg?kg(-1) i.p.) - induced catalepsy in mice (p?相似文献   

Phytochemical screening and evaluation of in vitro angiotensin-converting enzyme inhibitory activity of Artocarpus altilis leaf

This study investigates the effect of Artocarpus altilis leaf extracts on angiotensin-converting enzyme (ACE) activity. Among the extracts tested, hot ethanol extract exhibited a potent ACE-inhibitory activity with an IC?? value of 54.08?±?0.29?μg?mL?1 followed by cold ethyl acetate extract (IC?? of 85.44?±?0.85?μg?mL?1). In contrast, the hot aqueous extracts showed minimum inhibition with the IC?? value of 765.52?±?11.97?μg?mL?1 at the maximum concentration tested. Further, the phytochemical analysis indicated the varied distribution of tannins, phenolics, glycosides, saponins, steroids, terpenoids and anthraquinones in cold and hot leaf extracts. The correlation between the phytochemical analysis and ACE-inhibitory activity suggests that the high content of glycosidic and phenolic compounds could be involved in exerting ACE-inhibitory activity. In conclusion, this study supports the utilisation of A. altilis leaf in the folk medicine for the better treatment of hypertension. Further studies on isolation and characterisation of specific ACE-inhibitory molecule(s) from ethyl acetate, ethanol and methanol extracts of A. altilis leaf would be highly interesting.     

Chemical composition and antioxidant activities of ansu apricot oil growing wild in north Xinjiang, China

Ansu apricots growing wild in north Xinjiang are recognised as being one of the major wild-plant resources in China. In order to improve the level of comprehensive utilisation and the number of cultivated apricot varieties, the chemical composition of ansu apricot oil was analysed by capillary GC-MS and elucidated based on the standard mass spectral data; the antioxidant activities were also evaluated. Seven components of ansu apricots oil were identified, and the total unsaturated fatty acid (FA) (TUFA) and total essential FA (TEFA) contents of the ansu apricot oil were found to be 90.35 g/100 g and 48.93 g/100 g, respectively. The scavenging capacity of the ansu apricots oil in the superoxide anion radical system and the hydroxyl radical system performed better than in the DPPH radical system. The IC?? values of the ansu apricot oil for the superoxide anion radical system and the hydroxyl radical system were 0.15 mg mL?1 and 0.30 mg mL?1, respectively: stronger than that of the control (ascorbic acid). In the DPPH system, the IC?? value of the ansu apricot oil was 0.50 mg mL?1, and the IC?? value of ascorbic acid was 0.30 mg mL?1, but within the selected dosage, the highest scavenging capacity of ansu apricot oil was higher than the control. The results obtained in this study clearly suggest that ansu apricot oil is a natural source of antioxidants and could serve as a functional food ingredient with potential application in food products and thus provide related health benefits.     

Studies on the potential antioxidant properties of Senecio stabianus Lacaita (Asteraceae) and its inhibitory activity against carbohydrate-hydrolysing enzymes

This study showed for the first time the antioxidant and hypoglycaemic properties of the methanol, n-hexane and ethyl acetate extracts from Senecio stabianus Lacaita, a plant that belongs to the Asteraceae family. The antioxidant activities were carried out using two different in vitro assays, namely 2,2-diphenyl-1-picrylhydrazyl (DPPH) test and 2,2'-azinobis(3-ethylbenzthiazoline-6-sulphonate) (ABTS) test. The ethyl acetate extract showed the highest activity with inhibitory concentration 50% (IC(50)) values of 35.5 and 32.7?μg?mL(-1) on DPPH test and ABTS test, respectively. This activity may be related to a good total phenol and flavonoid content. All extracts were also tested for their potential inhibitory activity of α-amylase and α-glucosidase digestive enzymes. The n-hexane extract exhibited the highest α-amylase inhibition with an IC(50) value of 0.21?mg?mL(-1). Through bioassay-guided fractionation processes seven fractions (A-G) were obtained and tested. Based on the phytochemical analysis, the activity of n-hexane extract may be related to the presence of monoterpenes and sesquiterpenes.     

红花黄色素抗氧化活性研究

通过考察红花黄色素(SY)及其主要化学成分对羟基自由基介导2-脱氧核糖氧化降解的抑制作用,以及对1,1-二苯基-2-苦肼基自由基(DPPH·)的清除能力,探究SY的体外抗氧化活性及其抗氧化的主要有效成分.通过Fenton反应产生羟基自由基,用紫外分光光度计检测了SY及其主要化学成分对2-脱氧核糖降解的抑制作用和对DPPH·的清除能力,同时对红花黄色素B(SYB)抑制2-脱氧核糖降解的作用机制做了初步研究.结果表明SY抑制Fenton反应对2-脱氧核糖的氧化降解的IC50为256.79 μg/mL,对DPPH·清除的IC50值为27.15μg/mL.羟基红花黄色素A(HSYA)和SYB是SY中抗氧化的两个有效成分,抑制2-脱氧核糖的氧化降解的IC50分别为220.68 μg/mL和207.01μg/mL;对DPPH·清除的IC50值分别为55.81 μg/mL和41.25μg/mL.SYB对2-脱氧核糖氧化降解的抑制作用机理研究表明,SYB除了对Fenton反应产生的羟基自由基具有直接清除作用外,又可通过与Fe2+离子的络合作用而阻断Fenton反应产生羟基自由基.由此可知SY具有明显的体外抗氧化活性,SYB和HSYA为其主要抗氧化活性成分.     

Chemical composition and bioactivity of Citrus medica L. cv. Diamante essential oil obtained by hydrodistillation, cold-pressing and supercritical carbon dioxide extraction

The chemical composition of the essential oil of Citrus medica L. cv. Diamante peel obtained by hydrodistillation, cold-pressing and supercritical carbon dioxide extraction techniques was determined by GC/MS analysis. Forty-six components were fully characterised. Limonene and γ-terpinene were the major components of the oils obtained by hydrodistillation (HD) and cold-pressing (CP), while citropten was the major constituent in the oil obtained by supercritical carbon dioxide extraction (SFE). Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities were evaluated. The essential oil obtained by hydrodistillation exerted the highest inhibitory activity against BChE (IC?? value of 154.6 μg mL?1) and AChE (IC?? value of 171.3 μg mL?1. Interestingly, the oil obtained by cold-pressing exhibited a selective inhibitory activity against AChE. The essential oils have also been evaluated for the inhibition of NO production in LPS induced RAW 264.7 macrophages. The oil obtained by hydrodistillation exerted a significant inhibition of NO production with an IC?? value of 17 μg mL?1 (IC?? of positive control 53 μg mL?1).     

Antioxidant and antibacterial activities of bark extracts from Commiphora berryi and Commiphora caudata

This study investigates the in vitro antioxidant and antimicrobial activities of eight extracts obtained from the dried barks of Commiphora berryi and Commiphora caudata (Burseraceae). The radical scavenging activity was assessed by 1,1-diphenyl-2-picryl hydrazyl (DPPH) and nitric oxide assays. The methanolic extracts of C. berryi and C. caudata showed significant DPPH radical scavenging activity, with IC?? values of 26.92 and 21.16?μg?mL?1, respectively, and low radical scavenging activity against the nitric oxide assay. The antimicrobial activity of the plants was tested against the Gram-positive and Gram-negative bacteria. The ethyl acetate, chloroform and petroleum ether extracts of C. berryi showed good antibacterial activity against Pseudomonas aeruginosa, with a minimum inhibitory concentration (MIC) of 0.26?mg?mL?1, whereas the ethyl acetate and methanol extracts of C. caudata showed moderate antimicrobial activity with an MIC of more than 2.0?mg?mL?1 against P. aeruginosa compared to the petroleum ether and chloroform extracts, which showed an MIC of 1.1?mg?mL?1. The methanolic extracts of C. berryi and C. caudata also showed moderate cytotoxic activity against a human mammary carcinoma cell line (MCF-7), with values IC?? of 82.6 and 88.4?μg?mL?1, respectively.     

Antioxidant and antiproliferative activity of Laurus nobilis L. (Lauraceae) leaves and seeds essential oils against K562 human chronic myelogenous leukaemia cells

The antioxidant and antiproliferative activities of the essential oils from Laurus nobilis leaves and seeds in relation to their composition were analysed. The most abundant components of the leaf essential oil were 1,8-cineole, 1-p-menthen-8-ethyl acetate, linalool and sabinene, while the seed oil was characterised by β-ocimene, 1,8-cineole, α-pinene and β-pinene as main constituents. Both seed and leaf essential oils exhibited a scavenging effect on the DPPH radical, with IC?? values of 66.1 and 53.5?μg?mL?1, respectively. The leaf essential oil showed the strongest antioxidant activity in the β-carotene/linoleic acid system, with an IC?? value of 35.6?μg?mL?1 after 30?min of incubation. Both leaf and seed oils inhibited proliferation of the K562 tumour cell line with IC?? values of 95 and 75?μg?mL?1, respectively. The L. nobilis leaf oil showed a percentage of erythroide differentiation of 15% at a concentration of 10?μg?mL?1. A value of 12% was found for the seed essential oil at a concentration of 50?μg?mL?1. When the oils were added to a suboptimal concentration of the commercial drug, cytosine arabinoside, a clear synergic effect was observed.     

Antioxidant and anticancer activity of fresh corm extract from Romulea tempskyana (Iridaceae)

The antioxidant and anticancer properties of a medicinal plant, Romulea tempskyana (R. tempskyana) (Iridaceae) were investigated. The fresh corm water extract of R. tempskyana significantly increased cell viability against H(2)O(2) cytotoxicity(.) The extract also showed high inhibition of the lipid peroxidation activity (78.20%), reducing power (IC(50) 64.99?μg?mL(-1)) activity and hydroxyl (IC(50) 38.66?μg?mL(-1)), superoxide (IC(50) 25.99?μg?ml(-1)) and DPPH (IC(50) 19.88?μg?mL(-1)) radical scavenging activity. On the other hand, treatment of the cells with higher extract concentration showed the anticancer activity inducing cytotoxicity. The extract significantly affected Hepatoma G2 and H1299 cell proliferation (IC(50); 103.79 and 88.15?μg?mL(-1)). The amount of MDA (2-fold and 2.5-fold) and activities of several cellular antioxidant enzymes, including Se-GSPx (30%, 15%), non-Se-GSH-Px (11%, 16%) and GST (17%, 23%) increased in Hepatoma G2 and H1299 cells treated with IC(50) concentrations of extract, respectively. These findings suggest that R. tempskyana extract exhibits antioxidant and carcinogenesis-reducing potential.     

Antiatherogenic properties of acetone extract of Alpinia zerumbet seeds

Oxidation of low-density lipoprotein (LDL) is the principal risk factor for the development of atherosclerosis. In this study, we used several methods to investigate the ability of the acetone extract from rhizomes, stems, leaves, flowers, pericarps and seeds of Alpinia zerumbet to inhibit atherosclerosis in vitro. The seed extract had the strongest activity against tyrosinase, pancreatic lipase (PL), 15-lipoxygenase (15-LO) and LDL oxidation activities (IC?? = 2.30 ± 0.02, 5.00 ± 0.07, 1.29 ± 0.07 and 15.40 ± 0.86 μg/mL, respectively), amongst all different parts. It also had similar effects to the positive controls. Most of the extracts showed partial agonistic properties towards estrogenic activity. Cholest-4-ene-3,6-dione, a steroid present only in the seed extract seems to be the compound responsible for these activities. The results showed that cholest-4-ene-3,6-dione had similar ability to curcumin and quercetin against PL and LDL oxidation (IC?? = 19.50 ± 1.17 and 16.12 ± 1.43 μg/mL, respectively). Furthermore, cholest-4-ene-3,6-dione (IC?? = 34.21 ± 1.31 μg/mL) had higher inhibition against 15-LO than quercetin (IC?? = 54.79 ± 1.12 μg/mL).     

In vitro antioxidant and radical scavenging of Guinean kinkeliba leaf (Combretum micranthum G. Don) extracts

The antioxidant properties of the water and ethanol leaf extracts of kinkeliba (Combretum micranthum) were investigated, including scavenging of the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical (IC?? values: 8.02?±?0.34 for the ethanol extract [KE] and 9.1?±?0.28 for the water extract [KW]), the 2,2'-azinobis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical (IC(50) values: 7.4?±?0.14 for KE and 11.8?±?0.01 for KW) and the hydroxyl radical (58.1% for KE and 61.1% for KW). The ferric thiocyanate method, reducing power, metal chelating activity, an assay of protein oxidation and the β-carotene-linoleic bleaching assay were also used. Butylated hydroxytoluene and ascorbic acid were used as the reference antioxidant compounds. At 20 mg mL?1 concentration, KW and KE provided 36.8% and 75.1% inhibition of lipid peroxidation of linoleic acid emulsion, respectively. The IC?? values of the ethanol extract in ABTS and DPPH tests were significantly lower than those from the water extract. Furthermore, crude polyphenols were extracted from kinkeliba leaf with 90% ethanol solution using a water bath treatment and then purified by a macroporous resin, AB-8. The polyphenols from kinkeliba leaf were subjected to analyses by RP-HPLC and ESI-MS. The dominant polyphenols in kinkeliba leaf were identified as gallic acid, rutin trihydrate, (+)-catechin and benzoic acid.     

A new lignan from Oxytropis myriophylla

The 70% alcohol extract of Oxytropis myriophylla (PALL.) DC. (Leguminosae) exhibited high radical scavenging activity (IC(50) value: 88.0?μg?mL(-1) and 86.7?μg?mL(-1)) on 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical scavenging assays. Further chemical investigation led the isolation of one new lignan, namely myriophylloside G (1), together with three known compounds. Their structural elucidations of all the compounds were based on extensive spectroscopic methods, including HRESIMS and 2D NMR experiments (HSQC, HMBC and (1)H-(1)HCOSY) and by comparison with reference values.     

Butylated hydroxytoluene analogs: synthesis and evaluation of their multipotent antioxidant activities

A computer-aided predictions of antioxidant activities were performed with the Prediction Activity Spectra of Substances (PASS) program. Antioxidant activity of compounds 1, 3, 4 and 5 were studied using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and lipid peroxidation assays to verify the predictions obtained by the PASS program. Compounds 3 and 5 showed more inhibition of DPPH stable free radical at 10?? M than the well-known standard antioxidant, butylated hydroxytoluene (BHT). Compound 5 exhibited promising in vitro inhibition of Fe2?-induced lipid peroxidation of the essential egg yolk as a lipid-rich medium (83.99%, IC?? 16.07 ± 3.51 μM/mL) compared to α-tocopherol (α-TOH, 84.6%, IC?? 5.6 ± 1.09 μM/mL). The parameters for drug-likeness of these BHT analogues were also evaluated according to the Lipinski’s “rule-of-five” (RO5). All the BHT analogues were found to violate one of the Lipinski’s parameters (LogP > 5), even though they have been found to be soluble in protic solvents. The predictive polar surface area (PSA) and absorption percent (% ABS) data allow us to conclude that they could have a good capacity for penetrating cell membranes. Therefore, one can propose these new multipotent antioxidants (MPAOs) as potential antioxidants for tackling oxidative stress and lipid peroxidation processes.     

Prenylated xanthones from the bark of Garcinia xanthochymus and their 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities

Garcinia xanthochymus has been widely used in traditional Chinese medicine for expelling worms and removing food toxins. Bioassay-guided fractionation of an EtOAc-soluble extract of G. xanthochymus stem bark led to the isolation of six new xanthones. Their structures were elucidated by spectroscopic methods, especially 2D-NMR techniques. Free-radical-scavenging activities of the isolated compounds were elucidated through DPPH method. Most of the isolated compounds showed considerable free radical scavenging activity on DPPH assay. Compound 1 exhibited effective antioxidant scavenging activity against DPPH radical with an IC?? value of 19.64 μM, and compound 6 showed the lowest activity among all the tested molecules, with an IC?? value of 66.88 μM. These findings support the notion that the plant genus Garcinia is a good source of bioactive compounds.     

Composition of essential oil and antioxidant capacity of Centaurea drabifolia Sm. subsp. detonsa (Bornm.) Wagenitz, endemic to Turkey

In this study, composition of essential oil and antioxidant capacity of Centaurea drabifolia subsp. detonsa were investigated. The antioxidant capacity of the methanolic extract was evaluated by various methods including measuring the total phenolic content, total antioxidant capacity, free radical scavenging activity (DPPH assay), β-carotene/linoleic acid bleaching assay and ferric and cupric ion reducing power assay. The composition of essential oil was identified by using gas chromatography-mass spectrometry. Totally, 41 compounds were described in the essential oil. Germacrene D (44.829%) was determined as the major compound of the essential oil. The total phenolic content, total antioxidant capacity, inhibition rate of oxidation of linoleic acid, IC(50) (in DPPH assay) and EC(50) (in reducing power) value were found to be 40.454?mg?GAE/g, 100.840?mg?AAE/g, 65.639%, 39.584?μg?mL(-1) and 0.603?mg?mL(-1), respectively. The results indicated that the extract of C. drabifolia subsp. detonsa has strong antioxidant properties and this species can be used as a natural antioxidant in food processing and pharmaceutical industries.     

Phytochemical composition,in vitro antioxidant activity and antibacterial mechanisms of Neolamarckia cadamba fruits extracts

Aqueous extracts of Neolamarckia cadamba fruits prepared at different maturity stages were used for the analysis of various phytochemicals, and their antioxidant and antibacterial activities were determined. Ripe fruit extract had highest phenolics (3.14 mM GAE/ g fruit extract) with caffeic acid, tannic acid, syringic acid and quercetin as major phenolic compounds. The ripe fruit extract showed lowest IC₅₀ values in DPPH radical scavenging assay (231.33 μg fruit extract/ mL), and highest ABTS radical scavenging activity (111.18 μM TEAC/g). Immature fruit extract showed lowest minimum inhibitory concentration against tested bacteria, and the antibacterial activity was probably due to membrane permeation, as was evident by leakage of genetic material and reduction in propidium iodide uptake by bacterium; and by inhibition of sugar and amino acid uptake. The appreciable amount of phenolic compounds and biological activities in the aqueous extracts of N. cadamba fruits suggests it's potential application as natural preservative.