Antimicrobial, modulatory and chemical analysis of the oil of Croton limae.

CONTEXT: Croton sp. are plants with a well-reported antimicrobial activity. Croton limae A.P. Gomes, M.F. Sales P.E. Berry (Euphorbiaceae), known as 'marmeleiro-prateado', is commonly used to manage abdominal pain in Brazil. OBJECTIVE: This work evaluates the phytochemical composition, antimicrobial and modulatory activities of the essential oil of C. limae leaves (EOCL). MATERIALS AND METHODS: The minimum inhibitory concentration (MIC) and the modulation of the antibiotic activity were determined using a microdilution method. The concentration of EOCL ranged between 512 and 8 µg/mL. Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia, Candida tropicalis, C. krusei and C. albicans strains were used in the MIC and modulation assays. The antibiotics, amikacin, gentamicin and neomycin, and the antifungals, amphotericin B, benzoylmetronidazole and nystatin, were used in concentrations ranging between 2500 and 2.5 µg/mL. The phytochemical analysis of the EOCL was performed through gas chromatography coupled to a mass spectrometer (GC/MS). RESULTS: Only Staphylococcus aureus was inhibited by a clinically relevant concentration of EOCL (MIC 512 µg/mL). Synergism between the EOCL and amikacin against S. aureus (9.76 µg/mL) and E. coli (39.062 µg/mL); neomycin against E. coli (2.44 µg/mL); and benzoylmetronidazole against C. krusei (256 µg/mL) were observed. The GC/MS analysis identified cedrol, eucalyptol and α-pinene as the main compounds of EOCL. CONCLUSION: EOCL inhibited the growth of S. aureus and potentiated the antibiotic and antifungal effects of drugs against all bacterial and Candida strains, respectively.

Importancia medicinal del género Croton (euphorbiaceae) / Medicinal importance of Croton genus (euphorbiaceae)

Introducción: el género Croton que pertenece a la familia Euphorbiaceae, se caracteriza porque sus especies poseen una gran cantidad de usos a nivel etnobotánico. Esta información ha sido validada por los relatos ancestrales y los reportes bibliográficos que se han encontrado en los últimos cuarenta años. Se ubican muy cerca de la región del trópico y se encuentran distribuidas en Centroamérica, Suramérica, Asía y norte de África, de allí que se pueden observar los innumerables usos que tiene y que han llevado a profundizar en el estudio de las especies del género en estudio. Objetivos: realizar una búsqueda organizada, que permita reconocer el valor etnobotánico de especies del género Croton a nivel mundial, con el fín de determinar su valor e importancia medicinal. Métodos: fueron revisadas varias bases de datos, libros especializados y demás reportes bibliográficos relacionados con el uso tradicional de especies del género Croton y composición química. Resultados: la información de esta revisión, puede servir como base preliminar y como justificación en investigaciones relacionadas con la búsqueda de compuestos químicos del tipo flavonoide y diterpeno. Conclusiones: se evidenció de acuerdo al análisis de los datos obtenidos y la información obtenida en la presente revisión, que las especies del género Croton se caracterizan porque poseen un sinnúmero de usos en la medicina tradicional y popular(AU)

Introduction: The genus Croton Euphorbiaceae belonging to the family, is characterized by its species have a lot of uses ethnobotanical level, this information has been validated by the ancestral stories and bibliographic reports have been found in the last forty years, these species are located very close to the tropics and are distributed mainly in Central America, South America, Asia and north Africa, from there you can observe the many uses it has and which have led to further study of the genus study. Objectives: Perform an organized search, which allows recognizing the value ethnobotanical species of Croton worldwide, in order to determine its value and medicinal importance. Methods: Were revised several databases, specialized books and other bibliographic reports related to the traditional uses of species of Croton and chemical composition. Results: The information presented in this review may serve as a preliminary basis and as justification in research related to the search for chemical compounds specifically flavonoids and diterpenes. Conclusions: The results obtained in this review showed the evidence according to the analysis of the data and total information presented, that the genus Croton are characterized by has a wide use in traditional and folk medicine(AU)

Isolation, characterization and evaluation of antimicrobial and cytotoxic activity of estragole, obtained from the essential oil of Croton zehntneri (Euphorbiaceae).

Croton zehntneri (Euphorbiaceae) is a native aromatic plant from Northeast region of Brazil. The monoterpenoid estragole (ESL) has been isolated by classical chromatographic methods from the essential oil (EO) of C. zehnteneri leaves and characterized by GC-FID and GC-MS, its antimicrobial and cytotoxic potentials being assessed. The analysis of the EO enabled the identification of 100% of the integrated constituents, of which yield was about 1.8%. The main components identified were: eucalyptol, estragole (84.7%) and spathulenol. The dosage of 50 µg/disk of ESL presented fairly significant zones of inhibition against Gram-positive bacteria and fungi. The ESL presented toxicity against Artemia salina with LC50 and LC90 of 4,54 and 8,47 µg mL-1. However, in tumor inhibition assays (human cells), there were no rewarding inhibition in any of the human cancer cell lines (MCF-7, HEP-2 and NCI-H292).

Effects of the essential oil of Croton zehntneri and its major components, anethole and estragole, on the rat corpora cavernosa.

AIMS: The effects of the essential oil of Croton zehntneri (EOCz) and its major components anethole, estragole and methyl eugenol were evaluated in phenylephrine precontracted rat corpora cavernosa (RCC). MAIN METHODS: RCC strips were mounted in 5 ml organ baths for isometric recordings of tension, precontracted with 10 µM phenylephrine and exposed to test drugs. KEY FINDINGS: All major compounds relaxed RCC. The order of potency was estragole>anethole>methyl eugenol. The maximal relaxation to EOCz and methyl eugenol was 62.67% (IC50 of 1.67 µM) and 45.8% (IC50 of 1.7 µM), respectively. Estragole relaxed RCC with an IC50 of 0.6 µM (maximal relaxation-76.6%). The maximal relaxation to estragole was significantly reduced by L-NAME (43.46%-IC50 of 1.4 µM), ODQ (53.11%-IC50 of 0.83 µM) and indomethacin (24.41%-IC50 of 1.3 µM). On the other hand, anethole relaxed RCC by 66.73% (IC50 of 0.96 µM) and this relaxation was blunted by indomethacin (35.65%-IC50 of 1.6 µM). Both estragole and anethole increased the relaxation achieved upon electrical stimulation. Both compounds increased the levels of cAMP (estragole by 3-fold and anethole by 2-fold when compared to controls). Estragole also increased the levels of cGMP (0.5-fold). SIGNIFICANCE: The higher potency of these compounds to relax corpora cavernosa smooth muscle may form the pharmacological basis for the use of such substances as leading compounds in the search of alternative treatments of erectile dysfunction.

In vitro/in vivo characterization of nanoemulsion formulation of metronidazole with improved skin targeting and anti-rosacea properties.

Topical skin treatment was limited due to the lack of suitable delivery system with significant cutaneous localization and systemic safety. The aim of this study was to develop and optimize a nanoemulsion (NE) to enhance targeting localization of metronidazole (MTZ) in skin layers. In vitro studies were used to optimize NE formulations, and a series of experiments were carried in vitro and in vivo to validate the therapeutic efficacy of MTZ-loaded optimal NE. NE type selection and D-optimal design study were applied to optimize NE formulation with maximum skin retention and minimum skin penetration. Three formulation variables: Oil X1 (Labrafil), Smix X2 (a mixture of Cremophor EL/Tetraethylene glycol, 2:1 w/w) and water X3 were included in D-design. The system was assessed for skin retention Y1, cumulative MTZ amount after 24 h Y2 and droplet size Y3. Following optimization, the values of formulation components (X1, X2 and X3) were 4.13%, 16.42% and 79.45%, respectively. The optimized NE was assessed for viscosity, droplet size, morphological study and in vitro permeation in pig skin. Distributions of MTZ were validated by confocal laser scanning microscopy (CLSM). Active agent of NE transferred into deeper skin and localized in epidermal/dermal layers after 24 h, which showed significant advantages of the optimal NE over Gel. The skin targeting localization and minimal systemic escape of optimal NE was further proved by in vivo study on rat skin. Current in vitro-in vivo correlation (IVIVC) enabled the prediction of pharmacokinetic profile of MTZ from in vitro permeation results. Further, the in vivo anti-rosacea efficacy of optimal formulation was investigated by pharmacodynamics study on mice ear.

[GC-MS analysis of chemical components in seeds oil from Croton tiglium].

OBJECTIVE: To identify the chemical components and their relative content in seeds oil from Croton tiglium. METHODS: The oil obtained by extracting of the seeds of Croton tiglium with petroleum ether was subjected to methyl-esterification or dilution with ethylether. GC-MS were used to identify the components in croton oil,peak area normalization method was used to determine the relative content of these substances in the sample. RESULTS: Seventeen fat acid components were identified from croton oil. The main components were linoleic acid, oleic acid, and eicosenoic acid in methyl-esterified sample, whose quantities accouted for 77.33%. In addition, five aromatic compounds were also found in the sample diluted with ethylether, such as isoborneol, fenchyl alcohol, etc. Phorbol esters, having carcinogenesis and anti-HIV-1 effects, were not been identified. CONCLUSION: There are abundant of linoleic acid, oleic acid and eicosenoic acid in the seeds oil extracted from Chinese Croton tiglium. In contrast, the active component with carcinogenesis and anti-HIV-1 might be very rare in the samples and difficult to be obtained by ordinary separating and extracting methods.

Essential oil of Croton argyrophylloides: toxicological aspects and vasorelaxant activity in rats.

Croton argyrophylloides Muell. Arg. is widely used in Brazilian folk medicine to treat diabetes and venereal diseases. This study examined the acute toxicity and cytotoxicity of the essential oil of C. argyrophylloides (EOCA). In addition, vascular effects of the EOCA have been examined. In mice, an oral acute toxicity test revealed that EOCA could be considered as a non toxic essential oil since it showed a very high LD50 (9.84 +/- 0.01 g/kg). In the brine shrimp (Artemia salina) cytotoxic assay, the LC50 value of EOCA was 275 [165-534] microg/mL. EOCA (1-1000 microg/mL) relaxed isolated endothelium-intact aortic rings precontracted with phenylephrine with an IC50 value of 126.7 [89.8-163.7] microg/mL. In rat mesenteric bed preparations precontracted with phenylephrine, EOCA (1-300 microg/mL) also induced a reversible, vasodilator effect with an IC50 value of 46.0 [33.3-58.7] micro/mL. It is concluded that EOCA is a very interesting agent from the point of view of the possibility of therapeutic application. This is because, whilst showing a very small acute toxicity, EOCA also showed maximal efficacy as a vascular antispasmodic agent with a pharmacological potency similar to that of other Croton species essential oils.

Fluorine bearing sydnones with styryl ketone group: synthesis and their possible analgesic and anti-inflammatory activities.

In continuation of structure activity relationship studies, a panel of fluorine containing sydnones with styryl ketone group 4-[1-oxo-3-(substituted aryl)-2-propenyl]-3-(3-chloro-4-fluorophenyl)sydnones 2a-i, was synthesized as better analgesic and anti-inflammatory agents. The title compounds were formed by condensing 4-acetyl-3-(3-chloro-4-fluorophenyl)sydnone with various substituted aryl aldehydes, characterized by spectral studies and evaluated at 100 mg\kg b.w., p.o. for analgesic, anti-inflammatory and ulcerogenic activities. Compounds 2c and 2e showed good analgesic effect in acetic acid-induced writhing while none showed significant activity in hot plate assay in mice. In carrageenan-induced rat paw oedema test, compound 2c and 2f exhibited good anti-inflammatory effect at 3rd h, whereas compounds 2c, 2e, 2d, 2g and 2h showed activity in croton oil induced ear oedema assay in mice. Compounds 2c and 2e were less ulcerogenic than ibuprofen in rats, when tested by ulcer index method. Compounds with electron attracting substituents such as 2c and 2e were found to be promising in terms of the ratio of efficacy and adverse effect. These compounds generally exhibited better activity than those of earlier series signifying fluorine substitution.

12-O-Tetradecanoyl phorbol-13-acetate (TPA)-induced growth arrest is increased by silibinin by the down-regulation of cyclin B1 and cdc2 and the up-regulation of p21 expression in MDA-MB231 human breast cancer cells.

TPA is a potent regulator of cell growth, including cell proliferation and differentiation. In this study, we determined the effect of silibinin on TPA-induced growth arrest in breast cancer cells. Silibinin increased growth arrest of the G2/M phase in a dose-dependent fashion. Silibinin decreased the basal level of cyclin B1 and cdc2 expression, which is involved in S phase and G2/M transition. In addition, TPA-induced G2/M phase arrest was increased by silibinin. Under the same conditions, TPA-induced down-regulation of cyclin B1 and cdc2 was decreased by silibinin. In contrast, TPA-induced p21 expression was further increased by silibinin. To determine the regulatory mechanism of TPA-induced growth arrest, we pretreated cells with various inhibitors, such as UO126, SB203580, and LY294002. Interestingly, TPA-induced growth arrest was significantly increased by LY294002, but not by UO126 and SB203580. In addition, TPA-induced down-regulation of cyclin B1 was inhibited by LY294002; however, the basal level of p21 was increased by TPA and TPA-induced p21 expression was further increased by LY294002. Finally, adenoviral constitutively active-Akt (Ad-CA-Akt) overexpression regulated the up-regulation of cyclin B1 and the down-regulation of p21. Therefore, we have demonstrated that silibinin has an additive effect on TPA-induced growth arrest through the PI-3-kinase/Akt-dependent pathway.

Croton megalocarpus oil: a feasible non-edible oil source for biodiesel production.

This study presents the feasibility of converting a non-edible oil source native to the Africa region -croton megalocarpus oil to methyl esters (biodiesel) using sulfated tin oxide enhanced with SiO(2) (SO(4)(2-)/SnO(2)-SiO(2)) as super acid solid catalyst. This study was conducted using design of experiment (DoE), specifically, response surface methodology based on three-variable central composite design (CCD) with alpha (alpha)=2. The reaction parameters studied are: reaction temperature (60-180 degrees C), reaction period (1-3h) and methanol to oil ratio (1:6-1:24). Although the oil was found to contain high free fatty acid, however, yield up to 95% was obtained without any pre-treatment step with the following reaction conditions: 180 degrees C, 2h and 15:1 methanol to oil molar ratio, while keeping constant catalyst concentration and stirring speed at 3 wt.% and 350-360 rpm, respectively.

Larvicidal and nematicidal activities of the leaf essential oil of Croton regelianus.

The chemical composition of the leaf essential oil of Croton regelianus collected from wild plants growing in two different sites at Ceará State (Brazil) was analyzed by GC/MS and GC-FID. Twenty monoterpenoids, representing more than 96% of the chemical composition of the oils, were identified and quantified. The oils showed similar chemical composition but considerable variation in the levels of each constituent. Ascaridole (33.9-17.0%), p-cymene (22.3-21.6%), and camphor (13.0-3.1%) were the predominant constituents. The monoterpene ascaridole was isolated and characterized by spectroscopic data. The essential oils and the isolated compounds were tested against Aedes aegypti and Artemia sp. larvae, and the root knot nematode Meloidogyne incognita. The bioassay results show that the essential oil of C. regelianus and ascaridole were moderately active against the M. incognita, but strongly effective against both A. aegypti and Artemia sp. larvae.

Essential oil of croton nepetaefolius and its main constituent, 1,8-cineole, block excitability of rat sciatic nerve in vitro.

1. The effects of the essential oil of Croton nepetaefolius (EOCN) and its major constituent, 1,8-cineole, on the compound action potential (CAP) of nerve were investigated. 2. Experiments were performed in sciatic nerves dissected from Wistar rats, mounted in a moist chamber and stimulated at a frequency of 0.2 Hz, with electric pulses of 100 micros duration at 20-40 V. Evoked CAP were displayed on an oscilloscope and recorded on a computer. The CAP control parameters were as follows: peak-to-peak amplitude 8.1 +/- 0.6 mV (n = 15); conduction velocity 83.3 +/- 4.2 m/s (n = 15); chronaxie 58.0 +/- 6.8 msec (n = 6); and rheobase 2.8 +/- 0.1 V (n = 6). 3. Lower concentrations of EOCN (100 and 300 microg/mL) and 1,8-cineole (153 and 307 microg/mL; i.e. 1 and 2 mmol/L, respectively) had no significant effects on CAP control parameters throughout the entire recording period. However, at the end of 180 min exposure of the nerve to the drug, peak-to-peak amplitude was significantly (P < 0.05) reduced to 27.4 +/- 6.7 and 1.7 +/- 0.8% of control values by 500 and 1000 microg/mL EOCN, respectively (n = 6), and to 76.5 +/- 4.4, 70.0 +/- 3.9 and 14.8 +/- 4.1% of control values by 614, 920 and 1227 microg/mL (i.e. 4, 6 and 8 mmol/L) 1,8-cineole, respectively (n = 6). Regarding conduction velocity, at the end of the 180 min exposure period, this parameter was significantly reduced to 85.8 +/- 7.3 and 48.7 +/- 12.3% (n = 6) of control values by 500 and 1000 microg/mL EOCN, respectively, and to 86.4 +/- 4.5 and 76.1 +/- 5.2% (n = 6) by 920 and 1227 microg/mL 1,8-cineole, respectively. Chronaxie and rheobase were significantly increased by the higher concentrations of both EOCN and 1,8-cineole. 4. It is concluded that EOCN and its main constituent 1,8-cineole block nerve excitability in a concentration-dependent manner, an effect that was totally reversible with 1,8-cineole but not with EOCN. This suggests that other constituents of EOCN, in addition to 1,8-cineole, may contribute to the mediation of this effect of EOCN.

Protein kinase C translocation by modified phorbol esters with functionalized lipophilic regions.

Several novel phorbol esters were prepared with polar functional groups terminating their C12 and/or C13 acyl chains. Designed to be inhibitory protein kinase C (PKC) ligands, these phorbol analogues contain various polar functional groups (amide, ester, carboxylic acid, or quaternary ammonium salt) to prevent membrane insertion of the PKC-phorbol ester complex. All phorbol derivatives were synthesized with use of diterpene starting materials obtained from croton oil, the seed oil of Croton tiglium. The ability of these derivatives to recruit PKC to the lipid bilayer-a usual requirement for enzyme activation-was determined by using a sucrose-loaded vesicle assay. Phorbol 12-octanoate-13-acetate derivatives translocate PKC-betaII to increasing degrees as the functionality on the C12 ester becomes more hydrophobic. Likewise, PKC translocation by carboxylic acid-containing phorbol esters was dependent upon length and saturation of the hydrocarbon tether. The most promising PKC inhibitors had short carboxylic acids capping their C12 and C13 acyl chains, since these compounds did not recruit PKC to any appreciable extent.

A skin irritant phorbol ester from Euphorbia cooperi N E Br.

From the fresh latex of Euphorbia cooperi N E Br was isolated by partition and chromatographic methods, a diterpene ester 12-deoxyphorbol-16-isobutyrate-13-tigliate. The phorbol ester exhibited highly irritant activity on the mouse ear. Since skin irritancy is an indication of possible tumour promotion, the use of this plant as a medicine should be discouraged.