Nettle extract (Urtica dioica) affects key receptors and enzymes associated with allergic rhinitis

A nettle (Urtica dioica) extract shows in vitro inhibition of several key inflammatory events that cause the symptoms of seasonal allergies. These include the antagonist and negative agonist activity against the Histamine‐1 (H₁) receptor and the inhibition of mast cell tryptase preventing degranulation and release of a host of pro‐inflammatory mediators that cause the symptoms of hay fevers. The nettle extract also inhibits prostaglandin formation through inhibition of Cyclooxygenase‐1 (COX‐1), Cyclooxygenase‐2 (COX‐2), and Hematopoietic Prostaglandin D₂ synthase (HPGDS), central enzymes in pro‐inflammatory pathways. The IC₅₀ value for histamine receptor antagonist activity was 251 (±13) µg mL^?1 and for the histamine receptor negative agonist activity was 193 (±71) µg mL^?1. The IC₅₀ values for inhibition of mast cell tryptase was 172 (±28) µg mL^?1, for COX‐1 was 160 (±47) µg mL^?1, for COX‐2 was 275 (±9) µg mL^?1, and for HPGDS was 295 (±51) µg mL^?1. Through the use of DART TOF‐MS, which yields exact masses and relative abundances of compounds present in complex mixtures, bioactives have been identified in nettle that contribute to the inhibition of pro‐inflammatory pathways related to allergic rhinitis. These results provide for the first time, a mechanistic understanding of the role of nettle extracts in reducing allergic and other inflammatory responses in vitro. Copyright © 2009 John Wiley & Sons, Ltd.     

Taxodione and Extracts from Salvia austriaca Roots as Human Cholinesterase Inhibitors

Taxodione, an abietane diterpenoid, was isolated from Salvia austriaca transformed roots grown in in vitro conditions. The compound is known to have antibacterial, cytotoxic and anti‐tumour properties. This study evaluates the ability of pure taxodione and extracts obtained from the S. austriaca hairy roots and roots from field‐grown plants to inhibit human acetylcholinesterase and butyrylcholinesterase. Both extracts were found to have similar actions against acetylcholinesterase. The IC₅₀ for extracts from transformed and untransformed roots were 142.5 and 139.5 µg ml^?1, respectively. The highest activity towards human acetylcholinesterase was demonstrated by taxodione (IC₅₀ = 54.84 µg ml^?1). With respect to BChE inhibition, the root extracts demonstrated stronger activity (IC₅₀ = 23.6 µg ml^?1: field‐grown plants and 41.6 µg ml^?1: transformed roots) than taxodione (IC₅₀ = 195.9 µg ml^?1). Taxodione showed significant cytotoxicity against A549 cell line (IC₅₀ = 9.1 µg ml^?1), whereas the activities for the extracts from S. austriaca roots of field‐grown plants (IC₅₀ = 75.7 µg ml^?1) and hairy roots (IC₅₀ = 86.2 µg ml^?1) were lower. Computer modelling suggests that taxodione should not demonstrate cardiotoxic or genotoxic activity. It also indicates that taxodione should demonstrate very rapid transport from the body with very good blood–brain barrier penetration, but with no cumulative effect on the human body. The obtained results indicate that taxodione is a safe compound and may be used for further investigations in pharmacological activities. Copyright © 2015 John Wiley & Sons, Ltd.     

Tyrosinase and Cholinesterase Inhibitory Potential and Flavonoid Characterization of Viola odorata L. (Sweet Violet)

Inhibitory potential of the dichloromethane, ethyl acetate, ethanol, and aqueous extracts of Viola odorata L. (VO) was investigated against tyrosinase (TYR) and cholinesterases by microplate assays. The antioxidant activity was tested using six in vitro assays. Only the ethanol extract inhibited TYR (80.23 ± 0.87% at 100 µg mL^?1), whereas none of them were able to inhibit cholinesterases. The extracts were more able to scavenge NO radical (31.98 ± 0.53–56.68 ± 1.10%) than other radicals tested, and displayed low to moderate activity in the rest of the assays. HPLC analysis revealed that the aqueous extract of VO contained a substantial amount of vitexin (18.81 ± 0.047 mg g^?1 extract), while the ethanol extract also possessed rutin (1.31 ± 0.013 mg g^?1 extract) and vitexin (4.65 ± 0.103 mg g^?1 extract). Furthermore, three flavonoids (rutin, isovitexin, and kaempferol‐6‐glucoside) were isolated from the ethanol extract. This is the first report on TYR inhibitory activity of VO as well as presence of vitexin and isovitexin in this species. Copyright © 2015 John Wiley & Sons, Ltd.     

Cyclooxygenase‐2 inhibitory and antioxidant compounds from the truffle Elaphomyces granulatus

The ethanol extract of fruiting bodies of Elaphomyces granulatus, a truffle‐like fungus, was evaluated for cyclooxygenase‐2 (COX‐2) enzyme inhibitory and antioxidant activities. Inhibition of COX‐2 activity was evaluated in mouse macrophages (RAW 264.7). The extract of E. granulatus caused a 68% inhibition of COX‐2 activity at 50 µg/mL. Bioassay‐guided investigation led to the isolation and identification of two active compounds, syringaldehyde and syringic acid. Syringaldehyde moderately inhibited COX‐2 activity with an IC₅₀ of 3.5 µg/mL, while syringic acid strongly inhibited COX‐2 activity with an IC₅₀ of 0.4 µg/mL. The antioxidant activity of the extract and isolated compounds was evaluated in HL‐60 cells by the DCFH‐DA method. The extract of E. granulatus showed a potent antioxidant effect, with an IC₅₀ of 41 µg/mL. Of the pure compounds, syringic acid displayed a strong antioxidant activity, with an IC₅₀ of 0.7 µg/mL, while syringaldehyde showed no activity in the assay. Copyright © 2008 John Wiley & Sons, Ltd.     

Antimicrobial,antioxidant and anti‐inflammatory activity of young shoots of the smoke tree,Cotinus coggygria Scop

In this study, we investigated the antimicrobial activity of the young shoots of the smoke tree, Cotinus coggygria Scop., Anacardiaceae. The acetone extract and the derived ethyl acetate fraction effectively inhibited the growth of Gram‐positive and Gram‐negative bacteria (MIC 25–200 µg/ml), while the chloroform fraction showed pronounced activity against the yeast Candida albicans (MIC 3.12 µg/ml). The ethyl acetate fraction exhibited a significant ferric‐reducing ability (10.7 mmol Fe²⁺/g extract), a very high DPPH radical scavenging activity (SC₅₀ = 1.7 µg/ml) and inhibition of lipid peroxidation (IC₅₀ = 41.8 µg/ml). High amounts of total phenolics (929.8 mg/g), tannins (833.8 mg/g) and flavonoids (35.5 mg/g) were determined in the ethyl acetate fraction, which also exerted significant anti‐inflammatory (76.7%) and cytotoxic effects (IC₅₀ = 15.6 µg/ml). Copyright © 2012 John Wiley & Sons, Ltd.     

Evaluation of Turkish seaweeds for antiprotozoal, antimycobacterial and cytotoxic activities

As part of our continuing research on seaweeds, crude MeOH extracts of two green, three brown and six red algae collected from Marmara, Black, Aegean and Mediterranean Seas were screened. Four parasitic protozoa, i.e. Plasmodium falciparum, Trypanosoma brucei rhodesiense, T. cruzi, Leishmania donovani and the tubercle bacillus Mycobacterium tuberculosis were used as test organisms for the in vitro assays. The selective toxicity of the extracts was also determined against mammalian L6 cells. All seaweed extracts were active against T. brucei rhodesiense; the Dasya pedicellata extract was the most potent (IC₅₀ value 0.37 µg/mL). The same extract also weakly inhibited the growth of T. cruzi (IC₅₀ 62.02 µg/mL). All seaweed extracts also showed leishmanicidal activity (IC₅₀ values 16.76–69.98 µg/mL). The majority of the extracts also exhibited antiplasmodial potential and the most potent extracts were those from D. pedicellata (IC₅₀ 0.38 µg/mL), Codium bursa (IC₅₀ 1.38 µg/mL) and Caulerpa rasemosa (IC₅₀ 3.12 µg/mL). One brown and two red algal extracts showed some weak activity against Mycobacterium tuberculosis (MIC values 125–256 µg/mL). Except for the extract of Dasya pedicellata, none of the extracts displayed any cytotoxicity. This is the second study investigating the antiprotozoal activities of Turkish marine algae and identifies Dasya pedicellata, an understudied algal species, as a candidate for further studies. Copyright © 2010 John Wiley & Sons, Ltd.     

侧柏叶不同提取部位抑制胰脂肪酶及抗氧化活性筛选

目的:考察侧柏叶不同提取部位体外抑制胰脂肪酶活性和抗氧化活性。方法:对侧柏叶的醇提液、石油醚部位、乙酸乙酯部位、正丁醇部位、水部位采用体外抑制胰脂肪酶活性研究,并通过其清除1,1二苯基苦基苯肼(DPPH)自由基和Fe3+还原能力(FRAP)测定侧柏叶提取物的体外抗氧化作用。结果:侧柏叶提取物均有不同程度抑制胰脂肪酶活性,以乙酸乙酯部位效果最佳(IC50为26.09 mg·L-1),其次正丁醇部位(IC50为39.02 mg·L-1)和醇提物(IC50为98.20 mg·L-1),石油醚部位(IC50为188.27 mg·L-1)和水部位(IC50为325.28 mg·L-1)最弱。抗氧化活性依次为醇提液(DPPH IC50为7.59 mg·L-1,FRAP 4.40 mmol·g-1)乙酸乙酯部位(DPPH IC50为8.28 mg·L-1,FRAP 3.82 mmol·g-1)正丁醇部位(DPPH IC50为24.21mg·L-1,FRAP 1.77 mmol·g-1)水部位(DPPH IC50为27.53 mg·L-1,FRAP 1.38 mmol·g-1)石油醚部位。结论:初步确定侧柏叶抑制胰脂肪酶活性有效成分主要在乙酸乙酯与正丁醇部位,抗氧化及其相关成分主要在乙酸乙酯部位。     

Antiprotozoal activity of drimane and coloratane sesquiterpenes towards Trypanosoma brucei rhodesiense and Plasmodium falciparum in vitro

The extracts and 12 sesquiterpenes obtained from the East African medicinal plant Warburgia ugandensis Sprague (Canellaceae) were assessed for their antiplasmodial activity against the chloroquine‐sensitive (3D7) and chloroquine‐resistant (K1) strains of Plasmodium falciparum and antitrypanosomal activity against Trypanosoma brucei rhodesiense. The dichloromethane extract displayed strong antiplasmodial and antitrypanosomal activities with IC₅₀ values of 8.10 and 1.10 µg/mL against K1 strain of the malaria parasite and STlB900 strain of T. b. rhodesiense, respectively. Among the compounds evaluated for inhibition of trypomastigotes, both drimane and coloratane sesquiterpenes possessing aldehyde groups at positions 8 and 9 were found to show most antitrypanosomal activity with IC₅₀ values in the range 0.56–6.4 µM. The antiplasmodial assays also revealed that the six coloratane and six drimane sesquiterpenes isolated from this extract exhibited significant antitrypanosomal activity with IC₅₀ values ranged from 0.45 to ?114 µM. Among the compounds tested against the malarial parasite P. falciparum 11?‐hydroxymuzigadiolide (3) was most active with an IC₅₀ value of 6.40 µM. Copyright © 2010 John Wiley & Sons, Ltd.     

Medicinal Plants Traditionally Used for Treatment of Obesity and Diabetes Mellitus – Screening for Pancreatic Lipase and α‐Amylase Inhibition

In order to find new pancreatic lipase (PL) and α‐amylase inhibitors from natural sources for the treatment of obesity and related diseases as diabetes mellitus II, 23 medicinal plants with weight‐reducing, serum glucose‐reducing or related potential were investigated. Methanolic and water extracts of the plants were evaluated by using two in vitro test systems. Our findings have shown that the methanolic extract of Hibiscus sabdariffa L. (Malvaceae) showed high inhibitory activities to PL (IC₅₀: 35.8 ± 0.8 µg/mL) and α‐amylase (IC₅₀: 29.3 ± 0.5 µg/mL). Furthermore, the methanolic extract of Tamarindus indica L. (Leguminosae) showed a high anti‐lipase (IC₅₀: 152.0 ± 7.0 µg/mL) and the aqueous extract a high anti‐amylase (IC₅₀: 139.4 ± 9.0 µg/mL) activity. This work provides a priority list of interesting plants for further study with respect to the treatment of obesity and associated diseases. Copyright © 2015 John Wiley & Sons, Ltd.     

Tribulus terrestris (Linn.) Attenuates Cellular Alterations Induced by Ischemia in H9c2 Cells Via Antioxidant Potential

Tribulus terrestris L. was evaluated for its cardioprotective property against myocardial ischemia in a cell line model. Initially, methanolic extract was prepared and subjected to sequential extraction with various solvents. The extract with high phenolic content (T. terrestris L. ethyl acetate extract–TTME) was further characterized for its chemical constituents and taken forward for evaluation against cardiac ischemia. HPLC analysis revealed the presence of phenolic compounds like caffeic acid (12.41 ± 0.22 mg g^?1), chlorogenic acid (0.52 ± 0.06 mg g^?1) and 4‐hydroxybenzoic acid (0.60 ± 0.08 mg g^?1). H9c2 cells were pretreated with TTME (10, 25, 50 and 100 µg/ml) for 24 h before the induction of ischemia. Then ischemia was induced by exposing cells to ischemia buffer, in a hypoxic chamber, maintained at 0.1% O₂, 95% N₂ and 5% CO₂, for 1 h. A significant (p ≤ 0.05) increase in reactive oxygen species generation (56%), superoxide production (18%), loss of plasma membrane integrity, dissipation of transmembrane potential, permeability transition pore opening and apoptosis had been observed during ischemia. However, pretreatment with TTME was found to significantly (p ≤ 0.05) attenuate the alterations caused by ischemia. The overall results of this study partially reveal the scientific basis of the use of T. terrestris L. in the traditional system of medicine for heart diseases. Copyright © 2015 John Wiley & Sons, Ltd.     

Inhibitory Activities of Compounds from the Twigs of Garcinia hombroniana Pierre on Human Low‐density Lipoprotein (LDL) Oxidation and Platelet Aggregation

The methanol extract of the twigs of Garcinia hombroniana, which showed strong LDL antioxidation and antiplatelet aggregation activities, was subjected to column chromatography to obtain 3,5,3′,5′‐tetrahydroxy‐4‐methoxybenzophenone, 1,7‐dihydroxyxanthone and eight triterpenoids, garcihombronane B, D, E and F, friedelin, glutin‐5‐en‐3β‐ol, stigmasterol and lupeol. The structures of the compounds were elucidated by spectroscopic methods. The compounds were evaluated for their ability to inhibit copper‐mediated LDL oxidation and arachidonic acid (AA)‐, adenosine diphosphate (ADP)‐, collagen‐induced platelet aggregation in vitro. Among the compounds tested, 3,5,3′,5′‐tetrahydroxy‐4‐methoxybenzophenone and 1,7‐dihydroxyxanthone showed strong inhibitory activity on LDL oxidation with half‐maximal inhibitory concentration (IC₅₀) values of 6.6 and 1.7 µm , respectively. 3,5,3′,5′‐Tetrahydroxy‐4‐methoxybenzophenone exhibited strong activity on AA‐, ADP‐ and collagen‐induced platelet aggregation with IC₅₀ values of 53.6, 125.7 and 178.6 µm , respectively, while 1,7 dihydroxyxanthone showed significant and selective inhibitory activity against ADP‐induced aggregation with IC₅₀ value of 5.7 µm . Of the triterpenoids tested, garcihombronane B showed moderate activity against LDL oxidation and garcihombronane D and F showed selective inhibition on ADP‐induced platelet aggregation. Copyright © 2012 John Wiley & Sons, Ltd.     

Plants as a source of antimalarial drugs 5. Activities of Ailanthus altissima stem constituents and of some related quassinoids

Extracts from Ailanthus altissima (Mill.) Swingle Simaroubaceae have been tested for activity against Plasmodium falciparum in vitro and against P. berghei infections in mice. The activity of the chloroformic extract in vitro (IC₅₀ 5 μg ml-1) and in vivo (ED₅₀ 82.94 mg kg ^?1 d ^?1 after oral administration) is due principally to the presence of the quassinoid ailanthone (IC₅₀ in vitro 0.015μg ml^?1 ED₅₀ in vivo 0.76 mg kg^?1 d^?1). The constituent alkaloids canthin-6-one and 1-methoxycanthin-6-one are inactive in vitro. The in vitro and in vivo antimalarial activities of five related quassinoids, viz., ailanthinone, chaparrin, glaucarubol, glaucarubin, glaucarubinone are also reported.     

Antiviral and anticancer activities of 13(E)‐labd‐13‐ene‐8α,15‐diol isolated from Brachyglottis monroi

The antiviral activity of 13(E)‐labd‐13‐ene‐8α,15‐diol (1), isolated from Brachyglottis monroi, was examined against human rhinovirus 2 (HRV2) and 3 (HRV3), and the anticancer activity on human cancer cells (A549 and Hep2). Compound (1) showed strong anti‐HRV2 and HRV3 activity with a 50% inhibitory concentration (IC₅₀) of 2.68 and 0.87 µg/mL, respectively, and a 50% cytotoxicity concentration (CC₅₀) of 59.45 µg/mL. Ribavirin only showed anti‐HRV3 activity with an IC₅₀ of 30.48 µg/mL and a CC₅₀ > 100 µg/mL. The addition of compound (1) to HRV‐infected HeLa cells directly reduced the formation of visible cytopathic effect (CPE) and it directly interacted with HRV particles. Furthermore, A549 and Hep2 cells incubated with 32 µg/mL of compound (1) for 48 h exhibited antilung and antilaryngeal cancer activities, with a viability of less than 50%. These results suggest that compound (1) may be used as a potential antiviral and anticancer agent. Copyright © 2009 John Wiley & Sons, Ltd.     

木蹄复方体外抗肿瘤作用的实验研究

目的:筛选木蹄复方抗肿瘤活性提取物,初步分析其化学成分并观察其体外抗肿瘤效应.方法:常规水提和醇提的方法提取复方中水溶和醇溶性组分.MTT法测定木蹄复方水提取物(distilled water extract of compound Fomes fomentarius,WECF)和木蹄复方乙醇提取物(ethanol extract of compound F.fomentarius,EECF)对体外培养肿瘤细胞A549,Hela,QGY生长的抑制效应.系统预试法分析WECF化学组成.流式细胞术检测WECF对A549细胞凋亡的影响.结果:WECF对A549,Hela,QGY 3种细胞的IC50分别为(0.28±0.02),(0.40 ±0.06),(0.28±0.05) g·L-1;EECF对3种细胞的IC50分别为(0.50±0.04),(0.50±0.03),(0.60 ±0.06)g·L-1,WECF对肿瘤细胞的生长具有较强的抑制作用.WECF含有有机酸,氨基酸、多肽和蛋白质,糖、多糖和苷类,皂苷,内酯、香豆素及其苷类,植物甾醇、三萜成分以及挥发油和油脂,多糖含量为(16.1±0.5)％.WECF对A549,Hela,QGY,DU145,MDA-MB-435S,SGC-79016种细胞的IC50分别为0.29,0.45,0.32,0.32,0.83,0.23g·L-1; WECF 1 g·L-1作用于A549 24 h后,细胞凋亡率为22.0％.结论:WECF具有较强的体外抗肿瘤效果,对多种肿瘤细胞的生长具有非常明显的抑制作用,并可诱导A549细胞凋亡.     

Xanthine Oxidase Inhibitory Activity of Hungarian Wild‐Growing Mushrooms

Mushrooms represent a remarkable and yet largely unexplored source of new, biologically active natural products. In this work, we report on the xanthine oxidase (XO) inhibitory activity of 47 wild‐growing mushrooms native to Hungary. Aqueous and organic (n‐hexane, chloroform, and 50% methanol) extracts of selected mushrooms from different families were screened for their XO inhibitory activities. Among the 188 extracts investigated, the chloroform and 50% methanol fractions proved to be the most effective. Some species exhibited high inhibitory activity, e.g., Hypholoma fasciculare (IC₅₀ = 67.76 ± 11.05 µg/mL), Suillus grevillei (IC₅₀ = 13.28 ± 1.58 µg/mL), and Tricholoma populinum (IC₅₀ = 85.08 ± 15.02 µg/mL); others demonstrated moderate or weak activity. Additional studies are warranted to characterize the compounds responsible for the XO inhibitory activity of mushroom extracts. Copyright © 2014 John Wiley & Sons, Ltd.     

Anti‐complement activity of isolated compounds from the roots of Clerodendrum bungei Steud.

To determine the anti‐complement activity of natural diterpenes, chromatographic separation of the acetone‐soluble fraction from the roots of Clerodendrum bungei (Verbenaceae) led to the isolation of five diterpenoids. An acetone‐soluble extract of the roots of C. bungei exhibited significant anti‐complement activity on the classical pathway complement system, which was expressed as total hemolytic activity. Five compounds isolated from the roots of C. bungei, namely 12‐O‐β‐d ‐glucopyranosyl‐3,11,16‐trihydroxyabieta‐8,11,13‐triene (1), 3,12‐O‐β‐d ‐diglucopyranosyl‐11,16‐dihydroxyabieta‐8,11,13‐triene (2), ajugaside A (3), uncinatone (4) and 19‐hydroxyteuvincenone F (5). Compounds 1, 2, 3, 4 and 5 showed inhibitory activity against complement system with 50% inhibitory concentrations (IC₅₀) values of 24 µm , 138 µm , 116 µm , 87 µm and 232 µm . Among the compounds tested, 1 showed the most potent anti‐complement activity (IC₅₀, 24 µm ). Copyright © 2010 John Wiley & Sons, Ltd.     

Phytochemistry and Antileishmanial Activity of the Leaf Latex of Aloe calidophila Reynolds

Leishmaniasis is a major protozoal disease threatening the lives of 350 million people throughout the world. However, the therapeutic options for the disease are limited. In the present study, the antiprotozoal activity of the latex obtained from the Ethiopian plant Aloe calidophila Reynolds was evaluated by in vitro testing against Leishmania aethiopica and Leishmania major. It was found that the latex possesses moderate activity against both parasites with IC₅₀ values of 64.05 and 82.29 µg/mL, respectively. Phytochemical investigation resulted in the isolation of three anthrones identified as aloinoside, aloin, and microdontin on the basis of IR, MS, ¹H NMR, and ¹³C NMR spectral data. The isolated compounds showed strong antileishmanial activity with IC₅₀ values ranging from 1.76 to 6.32 µg/mL against L. aethiopica and from 2.09 to 8.85 µg/mL against L. major. Although these values were higher than those of amphotericin B (IC₅₀ = 0.109 and 0.067 µg/mL), the selectivity indices (813.35 and 694.90, respectively, against L. aethiopica and L. major) of aloinoside were much better than those of the standard drug (423.49 and 688.96). The results indicate that the isolated compounds have the potential to be used as a scaffold for the development of safe and cost‐effective antileishmanial agents. Copyright © 2014 John Wiley & Sons, Ltd.     

大孔树脂纯化紫心甘薯总黄酮及其抗氧化活性研究

 目的 研究紫心甘薯总黄酮的大孔树脂纯化工艺及其抗氧化活性。方法 以静态饱和吸附量和解析率为指标,对4种大孔树脂(D101,NKA-9,AB-8,NKA-Ⅱ)进行筛选,并以回收率为指标,通过选用L₉(3⁴)正交表设计实验,确立纯化总黄酮的最佳条件;以VC为对照品,采用邻苯三酚自氧化法和邻二氮菲法研究提取物对超氧阴离子(O^{－·₂)和羟基自由基(·OH)的抗氧化活性。结果 AB-8纯化紫心甘薯总黄酮效果最好,最佳纯化工艺：上样液质量浓度为0.81 mg·mL-1,淋洗pH为2,乙醇洗脱液体积分数为70%,洗脱流速为2 mL·min-1;邻苯三酚自氧化法和邻二氮菲法中抗氧化活性以半数抑制浓度(IC₅₀)表示分别为 0.037 4,0.105 mg·mL-1。结论 大孔树脂纯化紫心甘薯总黄酮的效果显著,紫心甘薯黄酮类化合物具有较强的抗氧化活性。}     

Inhibition of keratinocyte growth by different Nepalese Zanthoxylum species

A total of 11 methanol extracts obtained from four different Nepalese Zanthoxylum species were screened for their antiproliferative activity against the growth of human keratinocytes (HaCaT cells). The extract obtained from Z. armatum barks was highly active with an IC₅₀ value of 11 µg/mL. Also, the extracts ­obtained from Z. oxyphyllum barks and roots with IC₅₀ values of 53 and 57 µg/mL, respectively, showed potent activity. Their antiproliferative activity was not due to cytotoxic effects on cell membranes, as documented by the activity of lactate dehydrogenase released from the cytoplasm of keratinocytes, which did not exceed that of the control value. Rather, they also protected against radical‐induced ­damage to model membranes stimulated with 2,2′‐azo‐bis(2‐amidinopropane) dihydrochloride. Copyright © 1999 John Wiley & Sons, Ltd.     

Inhibitory Effect of Verbascoside Isolated from Buddleja brasiliensis Jacq. ex Spreng on Prolyl Oligopeptidase Activity

The phenylpropanoid glycoside verbascoside [2‐(3,4‐dihydroxyphenylethyl)‐1‐O‐α‐l ‐rhamnopyranosyl‐(1→3)‐β‐d ‐(4‐O‐caffeyl)‐glucopyranoside] (1) has been isolated as the main constituent of the crude extract of Buddleja brasiliensis Jacq. ex Spreng from Southern Brazil. The crude extract, main fractions and the compound 1 were evaluated for inhibition of the enzymes acetylcholinesterase (AChE), dipeptidyl peptidase‐IV (DPP‐IV) and prolyl oligopeptidase (POP). Compound 1 showed weak activity against DPP‐IV with an IC₅₀ >> 150 µm and was inactive against AChE, with a pMIQ determined by bioautography of 9.6. In contrast, 1 displayed significant inhibition of POP in a dose‐dependent manner with an IC₅₀ value of 1.3 ± 0.2 µm , similar to the positive control, baicalin, with a POP IC₅₀ of 12 ± 3 µm . Copyright © 2012 John Wiley & Sons, Ltd.