Flavonoids profiles,antioxidant, acetylcholinesterase inhibition activities of extract from Dryoathyrium boryanum (Willd.) Ching

The profiles and bioactivities of flavonoids extracted from Dryoathyrium boryanum (Willd.) Ching were investigated. The total flavonoids content in extract from D. boryanum is about 145.8 mg/g. By means of HPLC–DAD–ESI–MS, the main flavonoids in D. boryanum were tentatively identified as 3-hydroxyphloretin 6′-O-hexoside, quercetin-7-hexoside, apigenin7-O-glucoside, luteolin 7-O-glucoside, apigenin 7-O-galactoside, acacetin 7-O-(α-D-apio-furanosyl) (1 → 6)-β-d-glucoside, 3-hydroxy phloretin 6-O-hexoside, luteolin-6-C-glucoside. 0.21 mg/ml flavonoids extract from D. boryanum showed very strong superoxide anion radical scavenging potential, which is higher than that of rutin (0.25 mg/ml). The extract (0.21 mg/ml of flavonoids) from D. boryanum exhibited similar DPPH scavenging potential with that of rutin (0.25 mg/ml). However, rutin (0.25 mg/ml) showed a significantly higher reducing power and ABTS scavenging potential than that of 0.21 mg/ml flavonoids extract from D. boryanum. It had no effect on acetylcholinesterase. D. boryanum can be considered as a medicinal plant and the flavonoids from D. boryanum are excellent antioxidants.     

Synthesis of protopanaxadiol derivatives and evaluation of their anticancer activities

Protopanaxadiol (PPD), an aglycon of ginseng saponins, has shown anticancer activity in earlier studies. Here, we have reported the semisynthesis of nine PPD derivatives with acetyl substitutions. Subsequently, the antiproliferative effects of these nine analogs on different human cancer cell lines have been investigated. Compounds 1, 3, and 5 showed more significant and more potent antiproliferative activity compared with PPD and other derivatives. A flow cytometric assay indicated that compounds 1, 3, and 5 arrested cell cycle progression in the G1 phase and significantly induced apoptosis of cancer cells.     

远志地上部分10个黄酮类成分的分离及抗氧化活性研究(英文)

研究远志地上部分的化学成分并测试其抗氧化活性。运用硅胶、Sephadex LH-20、ODS及半制备液相,从远志地上部分中分离得到10个黄酮类化合物。用DPPH自由基清除试验测定了其抗氧化活性。分离所得化合物经光谱数据分析鉴定其结构分别为:异鼠李素-3-O-β-D-吡喃葡萄糖苷(1),异鼠李素-3-O-β-D-吡喃半乳糖苷(2),槲皮素-3-O-β-D-吡喃葡萄糖(1→2)-β-D-吡喃半乳糖苷(3),槲皮素-3-O-β-D-吡喃葡萄糖(1→2)-β-D-吡喃葡萄糖苷(4),蒙花苷(5),槲皮素-3-O-β-D-吡喃葡萄糖苷(6),5,7-二羟基-3-甲氧基黄酮-7-O-β-D-葡萄糖醛酸(7),异鼠李素(8),山奈酚(9)和槲皮素(10)。所有化合物均为首次从该植物中分离得到,化合物1–5和7均为首次从该属植物中分离得到。活性测试结果表明,化合物3、4、6、8、9和10表现出一定的抗氧化活性。     

UPLC快速测定石崖茶中5个黄酮类化合物含量及其体外抗氧化活性评价

目的:建立石崖茶中山茶苷A、山茶苷B、表儿茶素、槲皮苷和芹菜素5个黄酮类成分超高效液相色谱(UPLC)测定方法,初步评价石崖茶的体外抗氧化活性。方法:采用Waters Acquity BEH(2.1 mm×100 mm,1.7μm)色谱柱,水-乙腈作流动相,梯度洗脱,流速0.35 mL.min-1,检测波长280 nm(0～1.5 min)用于检测表儿茶素,330 nm(1.5～2.5 min和3.0～7.0min)检测山茶苷A、山茶苷B和芹菜素,254 nm(2.5～3.0 min)检测槲皮苷,柱温40℃,分析时间7 min。采用1,1-二苯基-2-苦基苯肼(DPPH)和2,2-联氮基-双-(3-乙基苯并噻唑啉-6-磺酸)二氨盐(ABTS)法测定石崖茶63%乙醇提取物的抗氧化活性。结果:山茶苷A、山茶苷B、表儿茶素、槲皮苷和芹菜素的线性范围分别为120.0～600.0,2.5～18.0,50.0～480.0,1.0～3.5,1.5～7.5 ng(r≥0.9996);平均加样回收率分别为98.03%,98.26%,100.8%,98.48%,100.2%;精密度、重复性和稳定性良好,RSD均小于2%。石崖茶抗氧化活性较维生素C弱,抗氧化活性与含测指标成分不呈相关性。结论:石崖茶具有一定抗氧化活性。该UPLC方法操作简便,检测结果准确,可为石崖茶的质量标准研究提供依据。     

Assessment of selected Yemeni medicinal plants for their in vitro antimicrobial,anticancer, and antioxidant activities

Context: The role of natural products as a source for remedies has been recognized since the beginning of mankind. Nevertheless, a minority of folkloricly used medicinal plants have been evaluated for their pharmacological activities.

Objectives: The purpose of this study is to evaluate 33 selected Yemeni plants for their in vitro anticancer, antimicrobial, and antioxidant activities.

Materials and methods: The plants were extracted with methanol and hot water. The obtained 66 extracts were tested for their in vitro cytotoxic activity using the neutral red uptake assay against two cancer cell lines (5637 and MCF-7). The antimicrobial activity was determined using the agar diffusion method and MIC-determination. The DPPH radical method was used for the determination of antioxidant activity.

Results: Interesting cytotoxic activity was observed for Hypoestes forskalei (Vahl) R. Br. (Acanthaceae), Lycium shawii Roem. & Schult. (Solanaceae), Pergularia tomentosa L. (Asclepiadaceae), Psiadia punctulata (DC.) Vatke (Compositae), Pulicaria petiolaris Jaub. & Spach (Compositae) and Rosmarinus officinalis L. (Labiatae) (IC₅₀ values < 50 μg/mL). Antimicrobial activity with MIC values ≤ 125 μg/mL was exhibited against Gram-positive bacteria by Chrozophora oblongifolia (Del.) A.Juss. ex Spreng. (Euphorbiaceae), Myrtus communis L. (Myrtaceae), Phragmanthera regularis (Steud. ex Sprague) M.G. Gilbert (Loranthaceae) and R. officinalis. Antioxidant activity was observed for C. oblongifolia, M. communis, and P. regularis.

Conclusion: The results justified the use of some investigated plants in the Yemeni ethnomedicine. These findings demonstrated that some of the investigated plants could be a source of new cytotoxic and antibiotic compounds; however, further work is needed.     

吉祥草总黄酮提取物的抗氧化活性评价

目的对吉祥草中总黄酮的体外抗氧化活性进行研究。方法采用盐酸-镁粉法测定黄酮含量,通过1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)法和铁离子还原(ferric ion antioxidant power,FRAP)法评价吉祥草总黄酮提取物的抗氧化活性。结果总黄酮提取物和脂溶性成分的EC50为(0.253±0.009)g·L-1,FRAP值为(0.964±0.028)mmol·g-1。结论吉祥草中总黄酮具有较强的抗氧化活性。     

Immunomodulatory and anticancer activities of flavonoids extracted from litchi (Litchi chinensis Sonn) pericarp

The litchi pericarp extract was subjected to partition by hexane, ethyl acetate and water. Epicatechin, proanthocyanidin B2 and proanthocyanidin B4 were isolated and purified from the ethyl acetate fraction by reverse-phase high performance liquid chromatography. The immunomodulatory activities of epicatechin, proanthocyanidin B2, proanthocyanidin B4 and the ethyl acetate fraction were examined using proliferation of mouse splenocytes. The results showed all these samples had much higher stimulatory effects on splenocyte proliferation than that of the reference, rutin. Epicatechin and the ethyl acetate fraction showed a significantly (P<0.05) stimulatory effect when the concentration was up to 12.5 micro g/ml. Proanthocyanidin B2 and proanthocyanidin B4 exhibited little lower stimulatory effects than epicatechin and the ethyl acetate fraction. The anti-breast cancer activities of epicatechin, proanthocyanidin B2, proanthocyanidin B4 and the ethyl acetate fraction were also evaluated. Epicatechin and proanthocyanidin B2 had lower cytotoxicities to human breast cancer cell MCF-7 and human embryolic lung fibroblast than paclitaxel.     

Synthesis of B-ring substituted flavones and evaluation of their antitumor and antioxidant activities

A series of flavones, substituted at the ring B, were synthesized using either Claisen–Schimdt Condensation or Baker–Venkataraman rearrangement. The synthesized compounds were tested for in vitro cytotoxic activity by sulforhodamine B assay against three cell lines of different origin, viz. HepG2, MCF-7, and MOLT-4. The compounds were also tested for a possible antioxidant activity by determination of inhibition of lipid peroxidation. Quercetin was taken as a standard for antioxidant activity. Compound 1c showed the highest cytotoxic activity against MCF-7 (GI50 < 0.1 μM) and MOLT-4 (GI50 < 0.1 μM) cell lines and was comparable to adriamycin, the standard used. Compounds 1b, 1g, and 1h also showed promising activity against MCF-7 and MOLT-4 cell lines. In the absence of a hydroxyl group, one or more methoxy groups present on the B-ring (compounds 1c–1e) were major determinants of inhibition of lipid peroxidation.     

溪黄草黄酮类化合物抑制亚硝化反应活性的研究

目的研究溪黄草黄酮类化合物对亚硝化反应的抑制作用。方法根据最佳提取工艺条件提取得到3个主要的黄酮类化合物,研究其对亚硝化反应的抑制作用。结果溪黄草总黄酮提取率可达91.98%,水溶性部分阻断亚硝胺的合成及清除亚硝酸盐作用较强,分离得到的3个黄酮类化合物中芦丁的抑制作用较强,对亚硝胺的合成的最大阻断率可达91.5%,对亚硝酸盐的最大清除率可达89.2%。结论溪黄草黄酮类化合物具有抑制亚硝化反应的活性。     

Study on the inhibition activities on nitrosation of flavonoids from Rabdosia serra

目的 研究溪黄草黄酮类化合物对亚硝化反应的抑制作用.方法 根据最佳提取工艺条件提取得到3个主要的黄酮类化合物,研究其对亚硝化反应的抑制作用.结果 溪黄草总黄酮提取率可达91.98％,水溶性部分阻断亚硝胺的合成及清除亚硝酸盐作用较强,分离得到的3个黄酮类化合物中芦丁的抑制作用较强,对亚硝胺的合成的最大阻断率可达91.5％,对亚硝酸盐的最大清除率可达89.2％.结论 溪黄草黄酮类化合物具有抑制亚硝化反应的活性.     

Characterization of polysaccharides and their antioxidant properties from Plumula nelumbinis

Two novel polysaccharides, Plumula nelumbinis (P. nelumbinis) polysaccharide I (LNP I) and P. nelumbinis polysaccharide II (LNP II), were extracted and purified from P. nelumbinis, and a sulfated polysaccharide, P. nelumbinis polysaccharide III (LNP III), with a substitution degree of 0.62 was prepared from LNPI. The structures of the LNPs were preliminarily characterized using high performance size exclusion chromatography (HPSEC), gas chromatography-mass spectrometry (GC–MS), Fourier transformed infrared spectrometry (FT-IR), and nuclear magnetic resonance (NMR) spectrometry. In addition, evaluation of the antioxidant activity of the LNPs showed that they could significantly increase the proliferation of RAW264.7 macrophages (P?<?0.05) and improve the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) based on cell model of H₂O_2-induced oxidative damage. This suggested that these LNPs may be used as potential antioxidants.     

Antimicrobial,antioxidant and anticancer activities of Laurencia catarinensis,Laurencia majuscula and Padina pavonica extracts

The antimicrobial, antioxidant, and anticancer activities of ethanolic extract of Laurencia catarinensis, L. majuscula and Padina pavonica were determined. The highest antibacterial activity; 23.40?±?0.58?mm (00.98?µg/ml) and 22.60?±?2.10?mm (03.90?µg/ml) were obtained against Klebsiella pneumonia by Laurencia catarinensis and Padina pavonica, respectively. However, Padina pavonica showed excellent antibacterial activity against Bacillus subtilis (21.7?±?1.5?mm; 1.95?µg/ml), Staphylococcus aureus (21.7?±?0.58?mm; 1.95?µg/ml), Streptococcus pyogenes (20.7?±?1.2?mm; 1.95?µg/ml) and Acinetobacter baumannii (20.1?±?1.2?mm; 3.9?µg/ml). Moreover, the highest antifungal activity; 24.7?±?2.0?mm (0.98?µg/ml), 23.7?±?1.5?mm (0.98?µg/ml), 23.6?±?1.5?mm (0.98?µg/ml) was obtained by Padina pavonica against Candida tropicalis, C. albicans and Aspergillus fumigatus, respectively. The algal extracts showed DPPH radical scavenging activity in a concentration–dependent manner with maximum scavenging activity (77.6%, IC₅₀?=?5.59?µg/ml and 77.07%, IC₅₀?=?14.3?µg/ml) was provided by Padina pavonica and Laurenica majuscula, respectively. The in vitro antitumor activity revealed that the IC₅₀ values of Padina pavonica were 58.9, 115.0, 54.5, 59.0, 101.0, 101.0, and 97.6?µg/ml; Laurencia catarinensis were 55.2, 96.8, 104.0, 78.7, 117.0, 217.0, 169.0?µg/ml; and Laurencia. majuscula were 115.0, 221.0, 225.0, 200.0, 338.0, 242.0, and 189.0?µg/ml; respectively against A-549 (Lung carcinoma), Caco-2 (Intestinal carcinoma), HCT-116 (Colon carcinoma), Hela (Cervical carcinoma), HEp-2 (Larynx carcinoma), HepG-2 (Hepatocellular carcinoma), and MCF-7 (Breast carcinoma) cell lines.     

山楂核中的芳香族化合物及其抗氧化活性

目的为寻找新的抗氧化剂来源,对蔷薇科山楂属植物山楂(Crataegus pinnatifida Bge.)核的体积分数70%乙醇提取物进行化学成分及其抗氧化活性的研究。方法运用D101大孔树脂、硅胶柱色谱、ODS柱色谱、制备HPLC等手段进行化学成分的分离纯化,根据理化性质及波谱数据鉴定其结构,并对分离得到的化合物进行DPPH和ABTS自由基清除抗氧化活性筛选实验研究。结果从山楂核体积分数为70%的乙醇水溶液的提取物中分离得到4个芳香族化合物,分别鉴定为threo-7R,8R-7-O-ethylguaiacylglycerol(1),erythro-7R,8S-7-O-ethylguaiacylglycerol(2),2,4-dimethoxyphenyl-1-O-β-D-glucopyranoside(3),vanillic acid-β-D-glucopyranoside(4)。结论化合物1和2为2个绝对构型未见报道的新化合物,化合物3和4为首次从山楂属植物中分离得到。同时,抗氧化活性结果显示化合物1和2具有较强的抗氧化活性。     

Preliminary screening of acetylcholinesterase inhibitory and antioxidant activities of Anatolian Heptaptera species

The ethyl acetate and methanol extracts prepared from the fruits, aerial parts, and roots of Heptaptera anatolica (Boiss.) Tutin, (Umbelliferae), H. anisoptera (DC.) Tutin, H. cilicica (Boiss. & Balansa) Tutin (endemic), and H. triquetra (Vent.) Tutin were tested for their acetylcholinesterase (AChE) inhibitory and antioxidant activities. AChE inhibition was evaluated using ELISA microplate reader at 500, 1000, and 2000 μg mL^?1. Antioxidant activity was determined by 2,2-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging test and Fe⁺²-ferrozine test system for metal chelating power at the same concentrations. Total phenol contents of the extracts were determined using Folin-Ciocalteu reagent. At 2000 μg mL^?1, only the aerial parts and fruits of H. anatolica showed moderate anti-AChE effect (61.97% and 49.80%, respectively), while the aerial parts and fruits of H. triquetra had the highest DPPH scavenging effect (80.48% and 86.19%, respectively). All of the methanol extracts exhibited significant ferrous ion-chelating effect varying between 72.97% and 92.36%, whereas only four of the ethyl acetate extracts exerted chelating effect over 70%. These results indicate that Heptaptera species could be a good source for antioxidant compounds.     

In vitro anti-nitrosative,antioxidant, and cytotoxicity activities of plant flavonoids: a comparative study

The ability of eight flavonoids to react with the biologically relevant reactive nitrogen species, nitric oxide, peroxynitrite, and nitrous acid were investigated in vitro, for the first time. All the investigated flavonoids were found to be potent reactive nitrogen and oxygen species scavengers and resulted in a significant inhibition of 3-nitrotyrosine (3-NT) formation in a dose-dependent manner. All the IC₅₀s were found at the μM level. The results reveal that, the presence of C₅–OH and C_4’–OH, in the flavonoid skeleton, enhanced the anti-nitrosative activity. The absence of the C₂=C₃ double bond and/or C₄-carbonyl group resulted in slight decrease of the anti-nitrosative activity. However, the presence of C₆- and/or C_3’-methoxy groups together with C_4’–OH dramatically decrease the inhibition capacity. Especially the free hydroxyl groups at 3’ and 4’ of the catechol containing ring B flavonoids as well as both hydroxyl groups at C₃ and C₅ are necessary for better antioxidant activity. The absence of both C₃–OH and/or C_3’–OH groups resulted in a remarkable decrease in the antioxidant activity. The cytotoxicity results indicate that the investigated flavonoids are safe to be used up to a concentration of 100 μM and may be utilized as promising sources of therapeutics.     

Two new c-glucosyl benzoic acids and flavonoids from Mallotus nanus and their antioxidant activity

Two new 2-C-β-D-glucopyranosyl benzoic acid derivatives named mallonanosides A (1) and B (2) were isolated from the methanolic extract of the leaves of Mallotus nanus along with five known flavonoids, kaempferin (3), juglanin (4), quercitrin (5), myricitrin (6), and rhoifolin (7). Their structures were established on the basis of spectral and chemical evidence. Their antioxidant activities were shown to depend on the number of hydroxyl groups, and the location and species of sugar moiety.     

Flavan-3-ol-phenylpropanoid conjugates from Anemopaegma arvense and their antioxidant activities

One of the species of commercially available catuaba was identified as Anemopaegma arvense by comparison of its micromorphological characteristics and TLC profile with six species of authenticated plants that are commonly referred to as catuaba. The bioactivity-guided fractionation of the ethyl acetate extract of the stem bark of this catuaba sample resulted in the isolation of one new (1, catuabin A) and three known flavan-3-ol type phenylpropanoids, cinchonain Ia (2), cinchonain IIa (3), and kandelin A1 (4) with antioxidant activities. The structures of these compounds were determined by a combination of spectroscopic techniques. Additionally, these compounds were tested for their anti-inflammatory, cytotoxicity, antimalarial, and antimicrobial activities, where no activity was observed.     

Cooperative inhibition of acetylcholinesterase activities by hexachlorophene in human erythrocytes

Hexachlorophene (HCP), pentachlorophenol (PCP), 2,4,5-trichlorophenol (2,4,5-TCP), and 2,4,6-trichlorophenol (2,4,6-TCP) all hemolyzed washed human erythrocytes and inhibited acetylcholinesterase (AchE) activities in erythrocyte membrane. HCP was much more potent in either effect than any other compound examined. The inhibition of AchE activities by HCP was reversed on adding albumin. The dose-response curves by HCP and PCP were sigmoidal, indicating cooperative inhibition, while those by 2,4,5-TCP and 2,4,6-TCP were not. Furthermore, the cooperativity of the inhibition by HCP was greater than by PCP. Differing from that by PCP, the cooperativity of inhibition increased depending on the temperature (13, 25, 37 °C) and decreased when the membrane was treated with Triton X-100. The cooperativity was also decreased in the presence of albumin. On a Scatchard plot analysis, erythrocyte membranes appeared to have multiple binding sites of different affinities for HCP; binding of HCP to the low affinity site [dissociation constant (Kd) 4.7 × 10^–5 M] seemed to be responsible for the observed cooperative inhibition of AchE activities. Neither neostigmine nor fenitrothion altered the cooperativity. HCP seems to be the most potent cooperative inhibitor of AchE in human erythrocyte membranes known to date. HCP may be useful to examine AchE and milieu in human erythrocyte membranes. Received: 17 June 1996 / Accepted: 25 July 1996