Chemopreventive and Antioxidant Activity of the Chamazulene‐Rich Essential Oil Obtained from Artemisia arborescens L. Growing on the Isle of La Maddalena,Sardinia, Italy

The essential oils of Artemisia arborescens growing in Sardinia (Italy), collected during three plant growth stages, i.e., from the vegetative stage to post‐blooming time, were characterized. Moreover, the in vitro antiproliferative and antioxidant activities of the oil isolated from aerial parts collected in February were evaluated. The essential oils belonged to the β‐thujone/chamazulene chemotype, notably with the highest amount of chamazulene (ca. 52%) ever detected up to now in the genus Artemisia and, in general, in essential oils. Quantitative variations in the oil composition were observed as the plant passes from the vegetative to the blooming stage. The oil was tested for its potential tumor cell growth‐inhibitory effect on T98G, MDA‐MB 435S, A375, and HCT116 human cell lines, using the MTT (=3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl‐2H‐tetrazolium bromide) assay. The highest activity was observed on A375 and HCT116 cell lines, with IC₅₀ values of 14 μg/ml. Moreover, the in vitro antioxidant and free radical‐scavenging assays revealed the oil to be an effective scavenger of the ABTS radical cation, with an activity comparable to that of Trolox^®. These results support the use of A. arborescens oil for the treatment of inflamed skin conditions. Finally, the composition of the polar fraction of the A. arborescens aerial parts was also examined, and the main component detected was 5‐O‐caffeoylquinic acid, which was identified for the first time in this plant.     

Composition and Antiviral Activity of the Essential Oils of Eryngium alpinum and E. amethystinum

The chemical compositions of the essential oils obtained by hydrodistillation of the aerial parts of Croatian Eryngium alpinum L. and E. amethystinum L. were characterized by GC‐FID and GC/MS analyses. The main components identified were the sesquiterpene β‐caryophyllene (19.7%) in the oil of E. amethystinum and the oxygenated sesquiterpene caryophyllene oxide (21.6%) in the oil of E. alpinum. Overall, 32 and 35 constituents were detected in the essential oils of the aerial parts of E. alpinum and E. amethystinum, respectively, representing 92.4 and 93.1% of the total oil compositions. The essential oils of both Eryngium species were proved to reduce the number of lesions in the local host Chenopodium quinoa infected with cucumber mosaic virus and an associated satellite. This is the first investigation of antiphytoviral activity of essential oils of Eryngium species.     

Immunosuppressive Activity of the Ethanol Extract of Sedum sarmentosum and Its Fractions on Specific Antibody and Cellular Responses to Ovalbumin in Mice

The immunosuppressive activity of the ethanol extract of Sedum sarmentosum (EESS) and its fractions was studied with respect to specific antibody and cellular response to ovalbumin (OVA) in mice. ICR Mice were immunized subcutaneously with OVA on days 0 and 14. Beginning on the day of immunization, the mice were administered intraperitoneally (ip) with EESS and it fractions at a single dose of 0.25, 0.5, and 1.0 mg, and cyclosporin A at a single dose of 0.1 mg at intervals of 7 days. On day 28, splenocyte proliferation and specific antibody level in serum were measured. EESS significantly suppressed concanavalin A (Con A)‐, lipopolysaccharide (LPS)‐, and OVA‐induced splenocyte proliferation in the immunized mice in a dose‐dependent manner. The OVA‐specific serum IgG, IgG1, and IgG2b levels in the immunized mice were also markedly reduced by EESS. Among four fractions of EESS, the BuOH fraction consisting mainly of flavonoid glycosides showed the highest suppressive activity. The results suggest that EESS could suppress the cellular and humoral immune response in mice, and deserve further research to be developed as immunosuppressant.     

Isolation, purification and characterization of beta-1,3-glucan binding protein from the plasma of marine mussel Perna viridis

A beta-1,3-glucan binding protein (betaGBP) specific for laminarin (a beta-1,3-glucan) was detected for the first time in a mollusc, Perna viridis. betaGBP was isolated and purified from the plasma using laminarin precipitation and affinity chromatography on laminarin-Sepharose 6B, respectively. It agglutinated bakers yeast, bacteria, and erythrocytes and enhanced prophenoloxidase (proPO) activity of the plasma in a dose-dependent manner. The purified betaGBP appeared as a single band in native-PAGE and the purity was conformed by HPLC. The protein has a molecular weight estimate of 510kDa as determined by SDS-PAGE and in isoelectric focusing the purified betaGBP was focused as a single band at pI 5.3. betaGBP was found to possess inherent serine protease activity but lacked beta-1,3-glucanase activity and all these results suggest that plasma betaGBP of P. viridis functions as a recognition molecule for beta-1,3-glucan on the surface of microbial cell walls. This recognition and binding lead to the activation of the prophenoloxidase cascade mediated by the inherent serine protease activity of betaGBP. Presence of agglutinating activity and serine protease activity shows that betaGBP is a bifunctional protein. The findings are discussed in light of the importance of this protein in the innate immune response of P. viridis, and they implicate evolutionary link with similar proteins found in other invertebrates.     

Viper and cobra venom neutralization by β-sitosterol and stigmasterol isolated from the root extract of Pluchea indica Less. (Asteraceae)

We reported previously that the methanolic root extract of the Indian medicinal plant Pluchea indica Less. (Asteraceae) could neutralize viper venom-induced action [Alam, M.I., Auddy, B., Gomes, A., 1996. Viper venom neutralization by Indian medicinal plant (Hemidesmus indicus and P. indica) root extracts. Phytother. Res. 10, 58-61]. The present study reports the neutralization of viper and cobra venom by beta-sitosterol and stigmasterol isolated from the root extract of P. indica Less. (Asteraceae). The active fraction (containing the major compound beta-sitosterol and the minor compound stigmasterol) was isolated and purified by silica gel column chromatography and the structure was determined using spectroscopic analysis (EIMS, (1)H NMR, (13)C NMR). Anti-snake venom activity was studied in experimental animals. The active fraction was found to significantly neutralize viper venom-induced lethal, hemorrhagic, defibrinogenation, edema and PLA(2) activity. Cobra venom-induced lethality, cardiotoxicity, neurotoxicity, respiratory changes and PLA(2) activity were also antagonized by the active component. It potentiated commercial snake venom antiserum action against venom-induced lethality in male albino mice. The active fraction could antagonize venom-induced changes in lipid peroxidation and superoxide dismutase activity. This study suggests that beta-sitosterol and stigmasterol may play an important role, along with antiserum, in neutralizing snake venom-induced actions.     

Anti‐Lipid Peroxidation, α‐Glucosidase and α‐Amylase Inhibitory Effects of the Extract of Capitula of Coreopsis tinctoria Nutt. and Protection Effects on High‐Fat/High‐Sugar and Streptozotocin‐Induced Type 2 Diabetes in Mice

Coreopsis tinctoria capitula (CTC) of the Compositae family has been used traditionally to treat various diseases in China, particularly type 2 diabetes mellitus (T2DM). This study evaluated the anti‐lipid peroxidation, α‐glucosidase and α‐amylase inhibitory effects of CTC extracts, and analyzed its chemical composition by HPLC. Moreover, the antioxidant activity and protection effects of CTC extracts were investigated on high‐fat/high‐sugar and streptozotocin‐induced T2DM mice. In vitro study, the ethyl acetate extract (EAE) and butanol extract (BE) of CTC exhibited anti‐lipid peroxidation (IC₅₀: BHA>BE or EAE>ascorbic acid, p<0.05) and α‐glucosidase inhibitory activity (IC₅₀: BE>EAE, p<0.05). In vivo, the BE at the dose of 600 mg/kg was intragastrically given to T2DM mice, which exhibited a certain extent of repair and improvement of the levels of CAT, GSH, GSH‐P_X, SOD, as well as plasma biomarkers, compared with those in the model group (p<0.05). These results demonstrated that CTC extracts have a positive effect to treat T2DM and it can be used for the treatment of T2DM in the future.     

Essential oils from the aerial parts of Centaurea cuneifolia Sibth. & Sm. and C. euxina Velen., two species growing wild in Bulgaria

The volatile constituents of the aerial parts of Centaurea cuneifolia Sibth. & Sm. and Centaurea euxina Velen. from Bulgaria were extracted by hydrodistillation and were analyzed. The main components in C. cuneifolia were β-eudesmol (26.5%) and hexadecanoic acid (17.6%). The main components in C. euxina were hexadecanoic acid (20.3%), spathulenol (10.8%) and caryophyllene oxide (6.2%). The chemotaxonomic significances with respect to other previously studied species of the same sections (Achrolopus and Phalolepis, respectively) are discussed.     

The effects of organic solvents on the efficiency and regioselectivity of N‐acetyl‐lactosamine synthesis,using the β‐galactosidase from Bacillus circulans in hydro‐organic media

The enzymatic synthesis of N‐acetyl‐lactosamine (LacNAc) by the transgalactosylation of N‐acetyl‐D ‐glucosamine (GlcNAc), catalyzed by the β‐galactosidase from Bacillus circulans (BcβGal), was studied in hydro‐organic media, starting from o‐nitrophenyl‐β‐D ‐galactopyranoside (oNPG) as a galactosyl donor. Thermal stability and synthesis activity of BcβGal were shown to depend on the organic solvent polarity, characterized by its Log P value. BcβGal was thus most stable in 10% (v/v) t‐BuOH, an organic solvent found to have a stabilizing and/or weakly denaturing property, which was confirmed for high t‐BuOH concentrations. In the same manner, the optimal synthesis yield increased as the Log P value of the organic solvent increased. The best results were obtained for reactions carried out in 10% (v/v) pyridine or 2‐methyl‐2‐butanol, which gave 47% GlcNAc transgalactosylation yield based on starting oNPG, of which 23% (11 mM; 4.3 g/L) consisted in LacNAc synthesis. Furthermore, it was also established that both the GlcNAc transgalactosylation yield and the enzyme regioselectivity depended on the percentage of organic solvent used, the optimal percentage varying from 10 to 40% (v/v), depending on the solvent. This phenomenon was found to correlate mainly with the thermodynamic activity of water (a_w) in the aqueous organic solvent mixture, which was found to be optimal when close to 0.96, whatever the organic solvent used. Finally, this study highlighted the fact that the regioselectivity of BcβGal for 1‐4 linkage formation could be advantageously managed by controlling the a_w parameter. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2010