Marisa Alves Nogueira Diaz

Screening of medicinal plants for antibacterial activities on Staphylococcus aureus strains isolated from bovine mastitis

Staphylococcus aureus is the main causative agent of bovine mastitis. The activity of several extracts from ten medicinal plants traditionally used in Brazil as antiseptic was investigated against fifteen strains of Staphylococcus aureus isolated from animals with mastitis manifestation by the disc diffusion method and broth microdilution assay. The interference of the extracts on cell in the form of adherent colonies was also evaluated. MIC values ranged from 0.5 mg/mL to 1.0 mg/mL and biofilm inhibitory concentration (BIC) were between 0.25 mg/mL and 0.8 mg/mL. Results revealed the potential of extracts of Senna macranthera, Artemisia absinthium, Cymbopogon nardus and Baccharis dracunculifolia as antibacterial agents against S. aureus strains isolated from bovine mastitis and support the possible use of these phytotherapic agents in the clinical management of the disease.

Effect of vitamin K in bone metabolism and vascular calcification: A review of mechanisms of action and evidences

ABSTRACT Osteoporosis is a public health concern associated with an increased risk of bone fractures and vascular calcification. Vitamin K presents unique benefits on these issues, although understudied. The two main forms of vitamin K are phylloquinone (vitamin K1) and menaquinone (vitamin K2). In this study, it was especially investigated the action of vitamin K2 in bones and vessels. Vitamin K2 has shown to stimulate bone formation by promoting osteoblast differentiation and carboxylation of osteocalcin, and increasing alkaline phosphatase, insulin-like growth factor-1, growth differentiation factor-15, and stanniocalcin 2 levels. Furthermore, vitamin K2 reduces the pro-apoptotic proteins Fas and Bax in osteoblasts, and decreases osteoclast differentiation by increasing osteoprotegerin and reducing the receptor activator of nuclear factor kappa-B ligand. In blood vessels, vitamin K2 reduces the formation of hydroxyapatite, through the carboxylation of matrix Gla protein and Gla rich protein, inhibits the apoptosis of vascular smooth muscle cells, by increasing growth arrest-specific gene 6, and reduces the transdifferentiation of vascular smooth muscle cells to osteoblasts. The commonly used dosage of vitamin K2 in human studies is 45 mg/day and its application can be an interesting strategy in benefitting bone and vascular health, especially to osteoporotic post-menopausal women.

Synthesis Approaches to (−)-Cytoxazone, a Novel Cytokine Modulator, and Related Structures

(−)-Cytoxazone, originally isolated from cultures of a Streptomyces species has an oxazolidin-2-one 4,5-disubstituted ring. It is known that this natural product presents a cytokine modulator effect through the signaling pathway of Th2 cells (type 2 cytokines), which are involved in the process of growth and differentiation of cells. From this, the interest in the development of research aimed at the total synthesis of this molecule and its analogs has remained high, which can be confirmed by the large number of publications on the topic, more than 30 to date. This review focuses on the various creative methods for the synthesis of (−)-cytoxazone and its congeners. The assessment of the preparation of this oxazolidinone and related structures serves as a treatise on the efforts made in the synthesis of this important class of compound from its first total synthesis in 1999.

Identification of phenolic compounds and biologically related activities from Ocotea odorifera aqueous extract leaves

Ocotea odorifera (Vell.) Rohwer is popularly used as food and flavoring. The aim of this study was to determine the chemical composition of the aqueous extract from O. odorifera leaves and evaluate the correlation of their phytochemical composition and biological activities. The antioxidant effect was determined by DPPH radical scavenging, β-carotene-linoleic acid and lipid peroxidation assays; the antibacterial activity was evaluated by the hole plate and MIC techniques and the antimutagenic activity was evaluated by the Ames test. Identification of phytochemicals was performed by LC-ESI/MS and the correlation between the phytochemical composition of the extract and the evaluated activities. The results allowed the identification of 13 phenolic compounds in the extract that exhibited high antioxidant activity and moderate antibacterial and antimutagenic action. Statistical analyses showed correlation of the total phenolic content with biologically related activities. The phytochemical analyses, together with the biological results, support the popular use of O. odorifera.

Chemical Constituents and an Alternative Medicinal Veterinary Herbal Soap Made from Senna macranthera

Upon undergoing biomonitoring, the most active dichloromethane extract retrieved from Senna macranthera roots led to the isolation of three main compounds: emodine, physione, and chrysophanol. In this sequence, these compounds revealed a potential antibacterial activity against Staphylococcus aureus strains isolated from animals with mastitis infections with minimum inhibitory concentration (MIC) values of 20, 90, and 90 μg mL−1, respectively. Therefore, an herbal soap was also produced from this same active extract. This soap was tested in vitro using gloves contaminated by animals with bovine mastitis that had been discarded after use by milkers and showed similar results to previously tested compounds. These results indicate the potential of this plant as an alternative veterinary medicine for the production of antibacterial soaps that aimed at controlling bovine mastitis infections in small Brazilian farms.

Easy Access to Evans' Oxazolidinones. Stereoselective Synthesis and Antibacterial Activity of a New 2-Oxazolidinone Derivative

An interesting new approach was developed for the synthesis of Evans’ chiral auxiliaries with excellent yields. In turn, another new stereoselective and efficient strategy has also allowed for the preparation of a 2-oxazolidinone derivative in 34% overall yield from the Morita-Baylis-Hillman adduct. The antibacterial activity of this oxazolidinone was tested against Staphylococcus aureus strains isolated from animals with mastitis infections.

Aloe vera-based formula as emollient on horses' hooves

The present study aimed at developing an Aloe vera-based formula for topical use on horse hoof and evaluating whether the treatment affects hooves growth and balance. Six healthy male horses between the ages of 3 and 17 years (12±5.25) were used, all semi-confined animals for breeding purposes. Before beginning A. vera treatment, animals underwent two trimming procedures with a 45 days-interval. After the second trimming, one of the forelimbs and one of the hindlimbs of 4 horses was weekly treated by topical application of the glycolic extract of A. vera at 20%. The contralateral limb, randomly chosen, received the extract at 50%. The hooves of the other animals were treated with propylene glycol. Treatment was done for 225 days and, during this time, animals underwent periodic trimming. Variables related to growth and balance of the hooves were measured before and after trimming. Data were analyzed using chi-square test and regression analysis at 5% significance. Growth rate of the hooves was not related to treatment. On the other hand, the 50% extract was related to the majority of the hooves in balance (p<0.05). Results suggest that a weekly topical treatment with A. vera glycolic extract does not improve the growth rate of the hooves; however, when applied at a high concentration, it improves their balance.

Enantioselective synthesis of both (-)-(R)-and (+)-(S)-angustureine controlled by enzymatic resolution

Uma nova sintese dos enantiomeros (-)-(R)- e (+)-(S)-angustureina, assim como do racemato (±)-angustureina, a partir de um b-amino ester racemico controlado por resolucao cinetica enzimatica, e descrita. Esta estrategia permitiu, incorporar tanto o esqueleto basico como controlar o unico estereocentro no carbono 2 de ambos enantiomeros. A sequencia em cinco etapas a partir dos b-amino ester e o carboxilato de sodio quirais para a sintese de ambos os alcaloides foi feita com um rendimento global de 80 e 44%, respectivamente, e excelentes excessos enantiomericos (95 e 96%, respectivamente) e sem nenhuma protecao de grupos funcionais em todas as etapas. The present study describes a new synthesis of (-)-(R)- and (+)-(S)-angustureine enantiomers, as well as of racemate (±)-angustureine, from a racemic b-amino ester controlled by kinetic enzymatic resolution. This strategy allowed to incorporate the basic skeleton, as well as to control the single stereocenter at carbon 2 in both enantiomers. The sequence of five steps starting from the chiral b-amino ester and sodium carboxylate for the synthesis of both alkaloids achieved overall yields of 80 and 44%, respectively, and produced excellent enantiomeric excesses (95 and 96%, respectively) with no protection of functional groups in any of the steps.

Antibacterial Chemical Constituent and Antiseptic Herbal Soap from Salvinia auriculata Aubl.

The bioassay-guided isolation of the active extract of Salvinia auriculata Aubl. led to the separation of three main compounds, characterized as stigmasterone, stigmasterol, and friedelinol. The pure form of diketosteroid presented a potential antibacterial activity with a minimum inhibitory concentration (MIC) value of 0.01 mg mL−1 against Staphylococcus aureus isolated from animals with mastitis infections. The active extract also showed a similar result to that previously obtained with pure diketosteroid when tested with the same isolates. The present studys results demonstrate the potential of this plant as an excipient for the production of antibacterial soaps aimed at controlling bovine mastitis infections, especially on small farms.

New Approach for the Stereoselective Synthesis of (+)-epi-Cytoxazone

The stereoselective total synthesis of (+)-epi-cytoxazone was performed satisfactorily in 8 steps, in 17% overall yield, via a novel route from 2,3-O-(3-pentylidene)-(R)-glyceraldehyde. The bulky group alkene-ketal allowed intramolecular control of the target molecule’s asymmetric centers in the dihydroxylation step by promoting the approach of OsO4 to the face opposite to that of the ketal group.