Eugenol derivatives: synthesis, characterization, and evaluation of antibacterial and antioxidant activities.

Eugenol is the major component of clove essential oil and has demonstrated relevant biological potential with well-known antimicrobial and antioxidant action. Therefore, this work carried out the synthesis, purification, characterization, and evaluation of the antioxidant and antibacterial potential of 19 eugenol derivatives. The derivatives were produced by esterification reactions in the hydroxyl group (-OH) of eugenol with different carboxylic acids and also by addition reactions in the double bond of the allyl group. The derivatives had a promising antibacterial potential, including a lower minimum inhibitory concentration of 500 µg/mL than eugenol (1000 µg/mL). In addition, the derivatives were active against bacterial strains (Escherichia coli, Staphylococcus aureus) that eugenol itself showed no activity, thus increasing the spectrum of antibacterial action. As for the antioxidant activity, it was observed that the derivatives that involved esterification reactions in the hydroxyl group (-OH) of the eugenol molecule's phenol resulted in a significant reduction of the antioxidant action (IC50 > 100 µg/mL) when compared with the eugenol precursor molecule (IC50 = 4.38 µg/mL). On the other hand, the structural changes located in the double bond affected much more smoothly the capacity of capturing radicals than the starting molecule, also being obtained derivatives with proximal antioxidant capacity (IC50 = 19.30 µg/mL) to commercial standards such as Trolox (IC50 = 16.00 µg/mL).

Triterpenes from Protium hebetatum resin.

Three olean (beta-amyrenone, beta-amyrin and maniladiol), three ursane (alpha-amyrinone, alpha-amyrin and breine) and four tirucallane (3-oxotirucalla-8,24-dien-21-6ic acid, 3alpha-hydroxytirucalla-8,24-dien-21-oic acid, 3alpha-acetoxytirucalla-8,24-dien-21-oic acid and 3alpha-hydroxytirucalla-7,24-dien-21-oic acid) triterpenes were isolated from the oleoresin of Protium hebetatum Daly. The structures were established mainly by 13C, 1D and 2D NMR spectroscopic analysis. The isolation of 3alpha-hydroxytirucalla-8,24-dien-21-oic acid permitted correction of the chemical shift assignments of some of its carbon atoms.

Chemical composition of the essential oils from two subspecies of Protium heptaphyllum / Composição química do óleo essencial de duas subespécies do Protium heptaphyllum

Qualitative and quantitative analyses of the volatile constituents from resin of Protium heptaphyllum (Aubl.) Marchand subsp. ulei (Swat) Daly (PHU), and Protium heptaphyllum (Aubl.) Marchand subsp. heptaphyllum (PHH), Burseraceae were performed using GC-MS and GC-FID. The resins were collected around the city of Cruzeiro do Sul, state of Acre, Brazil. Essential oils from the two subspecies were extracted by hydrodistillation with a yield of 8.6 percent (PHU) and 11.3 percent (PHH); the main components were terpinolene (42.31 percent) and p-cymene (39.93 percent) for subspecies ulei (PHU) and heptaphyllum (PHH), respectively.

As análises qualitativa e quantitativa dos óleos essenciais obtidos das resinas das espécies Protium heptaphyllum (Aubl.) Marchand subespécie ulei (Swat) Daly (PHU) e Protium heptaphyllum (Aubl.) Marchand subespécie heptaphyllum (PHH), Burseraceae, foram realizadas utilizando cromatografia em fase gasosa acoplado a um espectrômetro de massa (CG-EM) e cromatografia a gás com detector de chama (CG-DIC). As resinas foram coletadas no Município de Cruzeiro do Sul, Acre, Brasil. O óleo essencial das oleoresinas foi extraído por hidrodestilação fornecendo rendimento 8,6 por cento para PHU e 11,3 por cento para PHH. Os monoterpenos terpinoleno (42.31 por cento) e p-cimeno (39.93 por cento) foram os constituintes principais para PHU e PHH, respectivamente.

Studies on the cytotoxicity of cucurbitacins isolated from Cayaponia racemosa (Cucurbitaceae).

The cytotoxic potential of three cucurbitacins, 2,3,16,20(R),25-pentahydroxy-11,22-dioxo-cucurbita-5-en (cucurbitacin P, 1), 2,3,16,20(R),25-pentahydroxy-22-oxocucurbita-5-en (2) and 2,3,16,20(R),25-pentahydroxy-22-oxocucurbita-5,23(E)-diene (deacetylpicracin, 3), obtained from Cayaponia racemosa was evaluated as their ability to induce brine shrimp lethality, to inhibit the development of sea urchin eggs and tumor cell proliferation, and to lysis mouse erythrocytes. Compounds 1 and 2 were highly toxic with LC50 of (29.6+/-.1) (56.8) and (38.8 +/-.0) (76.6) micro/mL (umicro), respectively, while compound 3 was not effective at the tested concentrations. All tested compounds possessed an inhibitory effect on the proliferation of tumor cell lines, compound 1 being the most active, followed by 2 and 3. Nevertheless, no hemolytic activity or inhibition of the development of sea urchin eggs was observed for these compounds.