Naomi Kato Simas

Produtos naturais para o controle da transmissão da dengue: atividade larvicida de Myroxylon balsamum (óleo vermelho) e de terpenóides e fenilpropanóides

The bioassay-guided fractionation of the hexane extract obtained from the medicinal plant Myroxylon balsamum (red oil) was conducted in preparative thin layer chromatography on silica gel. The obtained fractions and some terpenoids and phenylpropanoids were assayed as larvicidal on third instar Aedes aegypti larvae, NPPN colony. The results indicate that the sesquiterpene nerolidol was the active constituent in the extract and that the sesquiterpenes were more active than the monoterpenes and phenylpropanoids utilized in this study. Lipophilicity seems to be an important property for the activity since the compounds with hydroxyl, carbonyl and methoxyl groups were less active. The results confirm also that essential oils can be a good tool for the control of dengue.

Chemistry and pharmacology of monimiaceae: a special focus on Siparuna and Mollinedia

The chemistry and pharmacology of species of the family Monimiaceae are reviewed, with special attention given to the genera Mollinedia and Siparuna, the two most important and representative in Brazil. The isolation of benzylisoquinoline alkaloids and kaempferol derivatives from Siparuna apiosyce is reported, as well as the isolation of aporphines from the fruits of Siparuna arianeae. Cinnamic acid derivatives and a gamma-lactone were isolated from Mollinedia gilgiana and Mollinedia marliae.

Potential use of Piper nigrum ethanol extract against pyrethroid-resistant Aedes aegypti larvae

Fractionation of Piper nigrum ethanol extract, biomonitored by assays on pyrethroid-resistant Aedes aegypti larvae yielded isolation of the larvicidal amides piperolein-A and piperine. Comparing LC50 values, the ethanol extract (0.98 ppm) was the most toxic, followed by piperolein-A (1.46 ppm) and piperine (1.53 ppm).

Flavonoids and a neolignan glucoside from Guarea macrophylla (Meliaceae)

This work describes the phytochemical study of the methanol extract obtained from leaves of Guarea macrophylla, leading to the isolation and identification of three flavonoid glycosides (quercetin 3-O-β-D-glucopyranoside, quercetin 3-O-b-D-galactopyranoside, kaempferol 7-O-β-D-glucopyranoside) and a neolignan glucoside, dehydrodiconiferyl alcohol-4-β-D-glucoside. All compounds were identified by a combination of spectroscopic methods (1H, 1D, 2D NMR, 13C and UV), ESI-MS and comparison with the literature data. This is the first report of flavonoids in the genus Guarea and of a neolignan glucoside in the Meliaceae family.

Antibacterial activity and cytotoxicity analysis of halistanol trisulphate from marine sponge Petromica citrina

OBJECTIVES An aqueous extract and fraction from the marine sponge Petromica citrina have antibacterial activity. We performed a chemical and biological characterization of the antibiotic substance from P. citrina and investigated its mode of action on Staphylococcus aureus cells. METHODS The inhibitory activity of the aqueous extract of P. citrina was determined against 14 bacteria belonging to type strains and clinical antibiotic-resistant strains. The aqueous extract was fractionated under bioassay guidance and the bioactive substance was identified by its (1)H-NMR, (13)C-NMR and mass spectra. The MIC and the MBC of this substance were determined. This substance was also subjected to cytotoxic bioassays. The mode of action on S. aureus cells was investigated by light and transmission electron microscopy analysis. RESULTS P. citrina showed a large spectrum of activity against type strains and resistant-bacteria such as S. aureus, Staphylococcus epidermidis, Enterococcus faecalis, Mycobacterium fortuitum and Neisseria gonorrhoeae. The aqueous extract was fractionated and halistanol trisulphate (24ε,25-dimethylcholestane-2β,3α,6α-triol trisodium sulphate) was isolated for the first time from P. citrina. Halistanol trisulphate had a bactericidal effect on exponentially growing S. aureus cells at the MIC (512 mg/L). Cytotoxicity biossays showed moderate toxicity against cancer cell line L929 (fibrosarcoma). This substance apparently acts by damaging the cell membrane, with subsequent cell lysis. CONCLUSIONS Halistanol trisulphate is a broad-spectrum antibiotic isolated from P. citrina with a mode of action involving disruption of the cytoplasmic membrane. It is a new candidate for research on antibacterial substances.

Distinct growth and extractive methods of Acmellaoleracea (L.) R.K. Jansen rising different concentrations of spilanthol: An important bioactive compound in human dietary

Acmella oleracea, commonly known as jambú, is a great source of spilanthol, a secondary metabolite responsible for different kind of biological activities, such as the antioxidant, antimicrobial, cytotoxic and anti-inflammatory bioactivities. The purpose of this work was to evaluate spilanthol content in A. oleracea plants obtained from three different cultivation conditions - in vitro, acclimatized and in field - and compare two different extraction techniques: maceration and microwave assisted extraction (MAE). Therefore, A. oleracea nodal segments were cultured on Murashige and Skoog medium. After 30days, developed plants were transferred to ex vitro conditions and successfully acclimatized. From all types of culture, the whole plant as well as the flowers, leaves, stems and roots were used, separately, to obtain ethanolic extract (75%) but only the micropropagated whole plant was used on the factorial design 24-1 on the microwave-assisted extraction. All the samples were quantified by HPLC-DAD and analyzed by CG-MS. Results show that the different acclimatized plant parts are the richest in spilanthol content, followed by the in vitro culture and, finally, field material. The MAE was able to extract the highest amount of spilanthol from in vitro whole plant (3.09%) compared to the classical maceration extract (0.98%) and, furnished good crude extracts yields under an optimized study accurately explained by the mathematical model. The antibacterial assay presented a negative result using in vitro samples and bacteria inhibition with field samples against Staphylococcus aureus (ATCC 29213) and Staphylococcus epidermidis (ATCC 12228) standard strains.

Allagoptera arenaria (Arecaceae): Leaf anatomy of a palm from the Brazilian shore

Allagoptera arenaria (Arecaceae), commonly known as “guriri,” is a palm that occurs only along the sandy coastal environments of Brazil. This work carries out a thorough analysis of A. arenaria leaf anatomy, including histochemistry and micromorphology, with special emphasis on leaf epicuticular waxes. Several common features of palms were identified, as well as characters not yet reported for the family or the species. Allagoptera arenaria pinnae possess a one-layered epidermis, hypodermis with two adaxial layers and one abaxial layer, homogeneous mesophyll composed of palisade cells, three different types of collateral veins, a prominent adaxial midrib, and silica inclusions. Although both margins of A. arenaria pinnae have a similar appearance, the shape of the leaf margins can vary. Scales or ramenta were found on the abaxial surface of the midrib on the median and basal portions of the pinnae. Histochemical analysis revealed the presence of polyphenols, flavonoids, lignin, and neutral and acidic lipids. The most distinctive character of A. arenaria pinnae is the presence of a thick layer of epicuticular waxes covering both the adaxial and abaxial surfaces. These results suggest the potential for exploiting A. arenaria as an alternative source of industrial waxes.

Anti-Escherichia coli activity of extracts from Schinus terebinthifolius fruits and leaves

Abstract Ethanol extracts obtained from Schinus terebinthifolius Raddi fruits and leaves were active against Escherichia coli with MIC of 78 μg mL−1 for both extracts. Phytochemical analyses revealed a major presence of phenolic acids, tannins, fatty acids and acid triterpenes in the leaves and phenolic acids, fatty acids, acid triterpenes and biflavonoids in the fruits. Major compounds isolated from the plant, such as the acid triterpene schinol, the phenolic acid derivative ethyl gallate and the biflavonoids agathisflavone and tetrahydroamentoflavone, showed very little activity against E. coli. Bioautography of the ethanol extracts on silica gel plate showed inhibition zones for E. coli. They were removed from the plate and the compounds identified as a mixture of myristic, pentadecanoic, palmitic, heptadecanoic, stearic, nonadecanoic, eicosanoic, heneicosanoic and behenic fatty acids.

In vitro effect of isoschaftoside isolated from Syngonium podophyllum on pig kidney Na+, K+-ATPase

The present study aimed to investigate the in vitro effects of isoschaftoside isolated from Syngonium podophyllum on pig kidney Na+,K+-ATPase. The Na+, K+-ATPase activity was determined by colorimetric measurement of inorganic phosphate (Pi), resulting from ATP hydrolysis. Isoschaftoside significantly decreased the renal Na+, K+-ATPase activity at the highest concentration as well as at a lower concentration. Our work suggests that isoschaftoside is a promising compound for the treatment of hypertension.