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Planta medica [journal]
- β-Carboline Alkaloids from Galianthe ramosa Inhibit Malate Synthase from Paracoccidioides spp. [JOURNAL ARTICLE]
- Planta Med 2014 Nov 20.
As part of our continuing chemical and biological analyses of Rubiaceae species from Cerrado, we isolated novel alkaloids 1 and 2, along with known compounds epicatechin, ursolic acid, and oleanolic acid, from Galianthe ramosa. Alkaloid 2 inhibited malate synthase from the pathogenic fungus Paracoccidioides spp. This enzyme is considered an important molecular target because it is not found in humans. Molecular docking simulations were used to describe the interactions between the alkaloids and malate synthase.
- Inhibitory Effect of Oleanolic Acid from the Rhizomes of Cyperus rotundus on Transient Receptor Potential Vanilloid 1 Channel. [JOURNAL ARTICLE]
- Planta Med 2014 Nov 17.
Cyperus rotundus is used as an analgesic and sedative in oriental medicine and has been reported to exhibit antinociceptive and anti-inflammatory effects. On the other hand, the transient receptor potential vanilloid 1 channel is a nonselective cation channel that senses various noxious chemical and thermal stimuli. However, it has recently been reported that the epidermally expressed transient receptor potential vanilloid 1 channel is involved in heat- and UV-induced skin aging. The aim of this study was to evaluate whether C. rotundus extract and its constituents can inhibit this channel. Ethylacetate and hexane fractions of the methanol extract were found to partially inhibit transient receptor potential vanilloid 1 channel activity, and at a concentration of 90 µM, oleanolic acid, which was one of three constituents isolated from the ethylacetate fraction, inhibited this activity by 61.4 ± 8.0 %. This is first electrophysiological study to be conducted on the effects of C. rotundus extract and its constituents on the transient receptor potential vanilloid 1 channel. The results obtained provide insight of the potential therapeutic effects of C. rotundus in the contexts of analgesia and UV-induced photoaging.
- Influence of Extra Virgin Olive Oil on Blood Pressure and Kidney Angiotensinase Activities in Spontaneously Hypertensive Rats. [JOURNAL ARTICLE]
- Planta Med 2014 Nov 11.
High-fat diets are associated with the development of cardiovascular diseases. The efficacy of the current strategies of treatment is still not entirely satisfactory, and new approaches are being considered. To analyze the beneficial effects of extra virgin olive oil as a major component of the Mediterranean diet, we studied systolic blood pressure and angiotensinase activities, since this enzyme is involved in the metabolism of angiotensins, in the kidney of hypertensive rats fed during 12 weeks with a diet enriched with extra virgin olive oil compared with a standard diet. As a reflex of oxidative stress, 8-isoprostanes and nitric oxide were quantified in urine. Results demonstrated a progressive increase in systolic blood pressure until the end of the feeding period in both groups. However, this increase was delayed in the extra virgin olive oil group until week six, with the systolic blood pressure being always lower in this group. Nitric oxide and 8-isoprostanes were lower in the extra virgin olive oil group. While we can deduce a higher formation of angiotensin 2-10 in the renal cortex, a higher availability of angiotensin II may be presumed in the renal medulla of animals fed an extra virgin olive oil diet than in animals fed a standard diet. Our results support the beneficial influence of extra virgin olive oil on cardiovascular function and suggest that the Mediterranean diet may be beneficial in itself but it may also be an effective tool in the treatment of hypertension.
- In Vitro Antihyperlipidemic Potential of Triterpenes from Stem Bark of Protorhus longifolia. [JOURNAL ARTICLE]
- Planta Med 2014 Nov 11.
Two lanostane triterpenes, 3β-hydroxylanosta-9,24-dien-21-oic acid (1) and methyl-3β-hydroxylanosta-9,24-dien-21-oate (2), were isolated from the stem bark of Protorhus longifolia. Their structures were deduced on the basis of spectroscopic analysis (NMR, HRMS, IR). This study investigated the in vitro anti-adipogenic activity of the two triterpenes. Their inhibitory activity was evaluated on selected lipid digestive enzymes (pancreatic lipase and cholesterol esterase). The inhibitory activity of the compounds on hormone-sensitive lipase and their ability to bind bile acids were also evaluated. The effect of the compounds on glucose uptake in C2C12 muscle cells and 3T3-L1 adipocytes, and on triglyceride accumulation in 3T3-L1 adipocytes was investigated. The triterpenes effectively inhibited the activities of the enzymes with IC50 values ranging from 0.04 to 0.31 mg/mL. The compounds showed a high affinity for secondary bile acids. Both compounds stimulated glucose uptake in C2C12 muscle cells and 3T3-L1 adipocytes. Compound 1 significantly reduced triglyceride accumulation in mature differentiated 3T3-L1 adipocytes. It is apparent that these lanostane triterpenes enhance glucose uptake and suppress adipogenesis, which together with their inhibitory effects on lipid digestive enzymes suggests that they have antihyperlipidemic potential.
- Antioxidant and Tyrosinase Inhibitory Effects of Neolignan Glycosides from Crataegus pinnatifida Seeds. [JOURNAL ARTICLE]
- Planta Med 2014 Nov 6.
In our efforts to find an inhibitor of melanin formation and develop potential depigmenting agents for skin-protecting cosmetics and medicinal products from natural resources, we focused on the seeds of Crataegus pinnatifida which showed antioxidant and tyrosinase-inhibiting activities. By activity-guided fractionation of an extract of C. pinnatifida seeds, four new neolignan glycosides, pinnatifidaninsides A-D (1-4), along with two known compounds (5-6), were isolated. Their structures were elucidated by spectroscopic analyses, especially 1D, 2D NMR and CD spectra. The antioxidant and tyrosinase-inhibiting activities of all isolates were assayed. Compound 6 showed good activity against 2,2-diphenyl-1-pikrylhydrazyl, while compounds 1, 2, 5, and 6 exhibited strong 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) free radical scavenging activity, being as effective as, or even more effective than the positive control Trolox. Moreover, compounds 5 and 6 displayed a moderate mushroom tyrosinase inhibitory activity.
- Schistosomicidal and Antioxidant Flavonoids from Astragalus englerianus. [JOURNAL ARTICLE]
- Planta Med 2014 Nov 5.
Astragalus englerianus is a close relative of the traditional Chinese medicine plant Radix Astragali (Huang-qi) and is mainly distributed in Yunnan. It has been traditionally used as a substitute of "Huang-qi" for reducing fatigue and enhancing immunity by local folks. A phytochemical study of the methanol extract of the roots led to the isolation of three new flavonoids including one aurone (1) and two chalcones (2 and 3), as well as two known flavonoids (4 and 5). Their structures were elucidated based on the analyses of extensive spectroscopic data and comparison of their physicochemical properties. This is the first report on the occurrence of β-hydroxydihydrochalcone, 2',5'-dioxygenchalcones, and 2',5'-dioxygenaurone in the genus Astragalus. All the isolated compounds were tested in vitro for their schistosomicidal and antioxidant activities. Compounds 2 and 4 showed schistosomicidal activities with worm mortality rates of 100 % within 12 h in a drug-containing (0.70 and 0.77 mM, respectively) RPMI 1640 medium. Compounds 1 and 2 exhibited antioxidant activities in 2,2-diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl free radical scavenging assays, with IC50 values of 35.9 ± 1.1 and 12.2 ± 1.1 µM, respectively.
- Diterpenes from Euphorbia piscatoria: Synergistic Interaction of Lathyranes with Doxorubicin on Resistant Cancer Cells. [JOURNAL ARTICLE]
- Planta Med 2014 Nov 5.
Four new diterpenes were isolated from the methanolic extract of Euphorbia piscatoria, two ent-abietanes (1, 2) and two lathyrane-type macrocyclic diterpenes (3, 4), along with three known diterpenes (5-7). Their structures were characterized by spectroscopic methods, mainly 1D and 2D NMR ((1)H, (13)C, DEPT, COSY, HMBC, HMQC, and NOESY) experiments. Compound 2, with an unusual structure, might be considered intermediate in the biosynthesis of ent-abietane α,β-unsaturated lactones, commonly found in Euphorbia species. Therefore, a possible biogenetic pathway is proposed. The MDR reversal potential of macrocyclic diterpenes 3-5 was evaluated through a drug combination assay, using the L5178Y mouse T lymphoma cell line transfected with the human MDR1 gene. Compounds 3-5 were able to enhance, synergistically, the antiproliferative activity of doxorubicin (combination indexes < 0.5). Moreover, compounds 1-6 were also assessed for their antiproliferative activity on human MDR cancer cell models, namely gastric, pancreatic, and colon. Weak antiproliferative activity was observed for compounds 1 (IC50 = 66.02 ± 7.10 µM) and 4 (IC50 = 39.51 ± 3.82 µM) on the MDR gastric cell line.
- Isomeric C12-Alkamides from the Roots of Echinacea purpurea Improve Basal and Insulin-Dependent Glucose Uptake in 3T3-L1 Adipocytes. [JOURNAL ARTICLE]
- Planta Med 2014 Nov 5.
Echinacea purpurea has been used in traditional medicine as a remedy for the treatment and prevention of upper respiratory tract infections and the common cold. Recent investigations have indicated that E. purpurea also has an effect on insulin resistance. A dichloromethane extract of E. purpurea roots was found to enhance glucose uptake in adipocytes and to activate peroxisome proliferator-activated receptor γ. The purpose of the present study was to identify the bioactive compounds responsible for the potential antidiabetic effect of the dichloromethane extract using a bioassay-guided fractionation approach. Basal and insulin-dependent glucose uptake in 3T3-L1 adipocytes were used to assess the bioactivity of extract, fractions and isolated metabolites. A peroxisome proliferator-activated receptor γ transactivation assay was used to determine the peroxisome proliferator-activated receptor γ activating properties of the extract, active fractions and isolated metabolites. Two novel isomeric dodeca-2E,4E,8Z,10E/Z-tetraenoic acid 2-methylbutylamides together with two known C12-alkamides and α-linolenic acid were isolated from the active fractions. The isomeric C12-alkamides were found to activate peroxisome proliferator-activated receptor γ, to increase basal and insulin-dependent glucose uptake in adipocytes in a dose-dependent manner, and to exhibit characteristics of a peroxisome proliferator-activated receptor γ partial agonist.
- The Endothelial Protective Properties of Essential Oil from Fructus Alpiniae zerumbet via the Akt/NOS-NO Signaling Pathway In Vitro. [JOURNAL ARTICLE]
- Planta Med 2014 Oct 28.
Oxidized low-density lipoprotein has been demonstrated to induce vascular injury, at least partly, through the nitric oxide-dependent pathway. Our previous studies showed that the essential oil from Fructus Alpiniae zerumbet had a capacity of antioxidation to ameliorate endothelial function and vasodilatation on aortic rings ex vivo. The present study aims to confirm the hypothesis that Fructus Alpiniae zerumbet protects against oxidized low-density lipoprotein-induced endothelial dysfunction in human aortic endothelial cells, and the role nitric oxide synthase plays in the process. Human aortic endothelial cells were pretreated with one of three different doses of Fructus Alpiniae zerumbet (1, 2, or 4 µg/mL), simvastatin (10 µM), or vehicle,followed by coincubation with oxidized low-density lipoprotein (150 µg/mL), for designed time periods. Exposure to oxidized low-density lipoprotein resulted in cytotoxicity accompanied by mitochondrial membrane potential collapse, excessive reactive oxygen species generation, and a decrease of nitric oxide production. The upregulation of inducible nitric oxide synthase mRNA and protein expression was determined by reverse transcription-polymerase chain reaction and Western blot analysis, respectively. Furthermore, oxidized low-density lipoprotein inhibited Akt phosphorylation and downregulated endothelial nitric oxide synthase and soluble guanylatecyclase in mRNA expression and the protein level. However, cytotoxicity and aberrant reactive oxygen species and nitric oxide generation caused by oxidized low-density lipoprotein could be significantly inhibited by Fructus Alpiniae zerumbet or Sim pretreatment. Results from this study confirmed that Fructus Alpiniae zerumbet could protect against oxidized low-density lipoprotein-induced endothelial dysfunction by antioxidation and modulating the Akt/nitric oxide synthase-nitric oxide signaling pathway.