Mevalonolactone: an inhibitor of Staphylococcus epidermidis adherence and biofilm formation.

Staphylococcus epidermidis, a commensal microorganism at the human skin and mucosae, is nowadays considered an important opportunistic pathogen related to nosocomial infections on indwelling medical devices due biofilm formation. Bacterial biofilms are the worst aspect in the treatment of infections and now efforts have been made in the search for new molecular entities to overcome this situation. In this work, a compound isolated from marine associated fungi was capable to interfere with the adherence and biofilm formation of S. epidermidis. This compound, identified as mevalonolactone, showed significant inhibition of S. epidermidis ATCC 35984 biofilm formation, without antibacterial activity, evaluated by crystal violet assay, turbidimetric assay and scanning electron microscopy. When assayed against 12 clinical isolates of S. epidermidis, this compound exhibited both biofilm inhibition and antimicrobial activity, but no activity against gram-negative bacteria was observed. Therefore, when this constitutive molecule is added in the antibiofilm and antibacterial assays, it might act as an important agent against this pathogen, contributing to the arsenal of antibiofilm compounds.

ANTIOXIDANT ACTIVITY OF BLACKBERRY ( Rubus sp. ) GENOTYPES FROM THE SOUTHERN REGION OF BRAZIL

The antioxidant activity and bioactive compounds of different blackberry fruit genotypes from the major Brazilian producer region (three cultivars and four selections) were evaluated and compared to the Cherokee cultivar. Phenolic and anthocyanic extracts were obtained and evaluated for each fruit genotype. The phenolic extracts of selections 02/96 and 07/001 presented higher antioxidant activity than those of cultivars in most assays. This activity was partially correlated to the higher amount of total phenolics in these samples. Thus, the phenolic compounds are probably the major responsible for the antioxidant activity in the diphenyl-2-picrylhydrazyl radical scavenging assay (DPPH), ferric reducing antioxidant power (FRAP) assay and thiobarbituric acid reactive substances (TBARS) assay. Quercetin seems to be responsible for the antioxidant activity of blackberry phenolic extracts in the ß-carotene bleaching assay. Concerning anthocyanic extracts, the selection 02/96 and Cherokee cultivar from harvest 2007 had higher antioxidant activity than the other genotypes in most assays. Anthocyanins appear to be the major responsible for the antioxidant activity of anthocyanic extracts in the DPPH and FRAP assays, although ascorbic acid also contributed to the DPPH antioxidant activity. Selection 02/96 appears to have higher antioxidant activity than the commercial cultivars cultivated in the southern Brazil and appears to be promising for nutritional and health purposes.

In vitro antiviral activity of marine sponges collected off Brazilian coast.

This paper describes the in vitro antiviral evaluation of 27 different marine sponges (Porifera) collected off Brazilian coastline in the search for novel drug leads. With these sponges aqueous and organic extracts were prepared and tested for anti-herpetic (HSV-1, KOS strain), anti-adenovirus (human AdV serotype 5) and anti-rotavirus (simian RV SA11) activities. The evaluation of the cytotoxicity and potential antiviral activity of these extracts were performed by using MTT assay. Results were expressed as 50% cytotoxicity (CC50) and 50% effective (EC50) concentrations, respectively, in order to calculate the selectivity indices (SI=CC50/EC50) of each extract. From the 40 sponge extracts tested, 17 extracts showed antiviral action in different degrees. The results concerning the antiviral activity were obtained by using three different strategies: (1) simultaneous assay, when sponge extracts were added to the cells at the same time of the viruses; (2) pre treatment assay, when sponge extracts were added to the cells 15 h prior to the viruses infection; and (3) post treatment assay, when the viruses were added to the cells and remained during 2 h prior to the addition of sponge extracts. The antiviral assays with HSV-1/KOS and AdV-5 showed more promising results when the pre treatment test was employed. In relation to the RV-SA11 virus, only the simultaneous assay showed antiviral activity. The extracts presenting the most promising results were the aqueous extracts of Cliona sp., Agelas sp.2, Tethya sp., Axinella aff corrugata, Polymastia janeirensis and Protosuberites sp., and these extracts deserve special attention in further studies.

Pilocarpine accumulation on Pilocarpus pennatifolius tissue culture

Callus and cell suspension cultures were established from young leaves of Pilocarpus pennatifolius on Murashige & Skoog (MS) medium supplemented with 5.0 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) and 1.0 mg/L kinetine. The pilocarpine contents of callus and cell suspension cultures were quantitatively compared by HPLC

Essential oils from Calyptranthes concinna, C. lucida and C. rubella (Myrtaceae)

Essential oils from Calyptranthes concinna, C. lucida and C. rubella, collected in Southern Brazil, were analyzed by GC and GC/MS. Sixty-two compounds were identified representing about 98 por cento of the oil contents. All samples were rich in cyclic sesquiterpenes (more then 90 por cento), mainly those from cadinane, bisabolane and germacrane cyclization pathway. The mainly components characterized were byclogermacrene (22.1 por cento in C. concinna; 11.7 por cento in C. rubella), cis-calamenene (10.3 por cento in C.concinna), beta-caryophyllene (16.5 por cento in C. rubella; 9.4 por cento in C. lucida), beta-bisabolene (25.5 por cento in C. lucida), spathulenol (15.4 por cento in C. rubella) and caryophyllene oxide (7.6 por cento in C. concinna)