Lack of antidiabetic effect of a Eugenia jambolana leaf decoction on rat streptozotocin diabetes

Streptozotocin-diabetic rats were treated for 17 days with a decoction of Eugenia jambolana (Myrtaceae) leaves (15%, w/v) as a substitute for water. Body weight, food and fluid intake, urine volume, glycemia, urinary glucose and urea were evaluated every 5 days. The animals were sacrificed by decapitation and blood samples collected for the determination of glycemia, serum cholesterol, HDL-cholesterol, triglycerides and angiotensin-converting enzyme. The weight of adipose and muscle tissues was also determined. There were no statistically significant differences between treated and untreated rats for any of the biochemical or physiological parameters. We conclude that, at least in this experimental model, Eugenia jambolana leaf decoction has no antidiabetic activity.

Cissampelos sympodialis Eichl (Menispermaceae) leaf extract induces interleukin-10-dependent inhibition of Trypanosoma cruzi killing by macrophages

The aqueous fraction of the ethanolic extract (AFL) of Cissampelos sympodialis Eichl (Menispermaceae), popularly known as milona, has been shown to have both immunosuppressive and anti-inflammatory effects. In the present study we investigated the modulation of macrophage antimicrobicidal activity by in vitro treatment with the extract from C. sympodialis. Normal and thioglycolate-elicited mouse peritoneal macrophages were infected in vitro with the protozoan Trypanosoma cruzi DM28c clone. We observed that the AFL (used at doses ranging from 13 to 100 µg/ml) increased T. cruzi growth and induced a 75% reduction in nitric oxide production. This inhibition could be mediated by the stimulation of macrophage interleukin-10 (IL-10) secretion since the in vitro treatment with the AFL stimulated IL-10 production by T. cruzi-infected macrophages. These results suggest that the anti-inflammatory effect of the AFL from C. sympodialis could be, at least in part, mediated by the inhibition of macrophage functions and that the inhibition of macrophage microbicidal activity induced by the C. sympodialis extract may be mediated by the decrease in macrophage function mediated by interleukin-10 production.

Low variation in ribosomal DNA and internal transcribed spacers of the symbiotic fungi of leaf-cutting ants (Attini: Formicidae)

Leaf-cutting ants of the genera Atta and Acromyrmex (tribe Attini) are symbiotic with basidiomycete fungi of the genus Leucoagaricus (tribe Leucocoprineae), which they cultivate on vegetable matter inside their nests. We determined the variation of the 28S, 18S, and 5.8S ribosomal DNA (rDNA) gene loci and the rapidly evolving internal transcribed spacers 1 and 2 (ITS1 and ITS2) of 15 sympatric and allopatric fungi associated with colonies of 11 species of leafcutter ants living up to 2,600 km apart in Brazil. We found that the fungal rDNA and ITS sequences from different species of ants were identical (or nearly identical) to each other, whereas 10 GenBank Leucoagaricus species showed higher ITS variation. Our findings suggest that Atta and Acromyrmex leafcutters living in geographic sites that are very distant from each other cultivate a single fungal species made up of closely related lineages of Leucoagaricus gongylophorus. We discuss the strikingly high similarity in the ITS1 and ITS2 regions of the Atta and Acromyrmex symbiotic L. gongylophorus studied by us, in contrast to the lower similarity displayed by their non-symbiotic counterparts. We suggest that the similarity of our L. gongylophorus isolates is an indication of the recent association of the fungus with these ants, and propose that both the intense lateral transmission of fungal material within leafcutter nests and the selection of more adapted fungal strains are involved in the homogenization of the symbiotic fungal stock.

Inotropic effect of Citrus sinensis (L.) Osbeck leaf extracts on the guinea pig atrium

The objective of the present investigation was to determine the contractile effect of crude and acetone leaf extracts of Citrus sinensis (L.) Osb. on mammalian myocardium. Crude leaf extracts have been used in folk medicine to treat neurological disorders. Some flavonoids isolated from this plant presented a positive inotropic effect on myocardium. This motivated us to test the extracts on the atria of guinea pigs of both sexes (300-500 g) and surprisingly we observed inotropic depression instead of an increase in force. The maximum effect of the crude extract was 79.4 ± 8.1% of the control force amplitude (N = 5 hearts, 10 trials, 27 ± 0.1ºC, stimulus: 2 Hz, 400 V, 0.5 ms). The EC50 for crude, ethanol, acetic, aqueous, and acetone extracts was 300, 300, 600, 1000, and 140 µg/ml, respectively, with a Hill constant of 1.8, 2.0, 2.5, 2.0, and 1.4, respectively. Blockade of cholinergic, beta-adrenergic, or opioid membrane receptors with 1.5 µM atropine sulfate, 1 µM propranolol, and 10 µM naloxone, respectively, did not change the effect of the crude extract. The acetone extract abolished the Bowditch positive staircase phenomenon (N = 5 hearts, 10 trials, 27 ± 0.1ºC), suggesting a possible reduction of the calcium inward current, and also promoted the so-called Woodworth phenomenon. The effect was concentration-dependent and indicated the existence of another inhibitory contractile mechanism such as the simultaneous activation of some of the membrane potassium channels reducing the myocardial action potential duration and further decreasing the cellular calcium entry.

Ginkgo biloba leaf extract (EGb 761) enhances catalepsy induced by haloperidol and L-nitroarginine in mice

Ginkgo biloba extract EGb 761 has been reported to have therapeutic effects which have been attributed to anti-oxidant and free radical-scavenging activities, including a direct action on nitric oxide production. L G-nitro-arginine (L-NOARG), a nitric oxide synthase inhibitor, and haloperidol, a drug that blocks dopamine receptors, are both known to induce catalepsy in rodents. Nitric oxide has been shown to influence dopaminergic transmission in the striatum. The purpose of the present study was to evaluate the effect of the extract obtained from leaves of Ginkgo biloba tree EGb 761 on catalepsy induced by haloperidol or by L-NOARG. Albino Swiss mice (35-45 g, N = 8-12) received by gavage a single or repeated oral dose (twice a day for 4 days) of EGb 761 followed by ip injection of haloperidol or L-NOARG. After the treatments, the animals were submitted to behavioral evaluation using the catalepsy test. Acute treatment with 80 mg/kg EGb did not modify the catalepsy induced by L-NOARG but, the dose of 40 mg/kg significantly enhanced haloperidol-induced catalepsy measured at the 10th min of the test. After repeated treatment with 80 mg/kg EGb 761, a significant increase in the cataleptic effect produced by both haloperidol and L-NOARG was observed. These data show that repeated EGb 761 administration increases the effects of drugs that modify motor behavior in mice. Since the catalepsy test has predictive value regarding extrapyramidal effects, the possibility of pharmacological interactions between haloperidol and Ginkgo biloba extracts should be further investigated in clinical studies.

Cytotoxicity of Marchantia convoluta leaf extracts to human liver and lung cancer cells

The cytotoxicity of three extracts (petroleum ether, ethyl acetate and n-butanol) from a plant used in folk medicine, Marchantia convoluta, to human non-small cell lung carcinoma (H1299) and liver carcinoma (HepG2) cell lines was tested. After 72-h incubation of lung and liver cancer cell cultures with varying concentrations of extracts (15 to 200 µg/mL), cytotoxicity was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and reported in terms of cell viability. The extracts that showed a significant cytotoxicity were subjected to gas chromatography-mass spectrometry analysis to identify the components. The ethyl acetate, but not the petroleum ether or n-butanol extract, had a significant cytotoxicity against lung and liver carcinoma cells with IC50 values of 100 and 30 µg/mL, respectively. A high concentration of ethyl acetate extract (100 µg/mL) rapidly reduced the number of H1299 cells. At lower concentrations of ethyl acetate extract (15, 30, and 40 µg/mL), the numbers of HepG2 cells started to decrease markedly. Gas chromatography-mass spectrometry analysis of the ethyl acetate extract revealed the presence of several compounds such as phytol (23.42%), 1,2,4-tripropylbenzene (13.09%), 9-cedranone (12.75%), ledene oxide (7.22%), caryophyllene (1.82%), and caryophyllene oxide (1.15%). HPLC analysis result showed that there were no flavonoids in ethyl acetate extract, but flavonoids are abundant in n-butanol extract. Further studies are needed regarding the identification, toxicity, and mechanism of action of active compounds.

Antinociceptive effects of the essential oil of Mentha x villosa leaf and its major constituent piperitenone oxide in mice

Mentha x villosa Huds (Labiatae) is an aromatic herb widely used in folk medicine. Since the essential oil of the herb has many pharmacological activities, including antispasmodic effects, we determined whether the oil and its major constituent, piperitenone oxide (PO), have antinociceptive activity. The essential oil of M. x villosa (EOMV) and PO administered orally at 200 mg/kg (vehicle: 0.1% Tween 80 in water) significantly reduced the writhings induced by acetic acid from control values of 59.5 ± 3.1 s (N = 10) to 31.9 ± 2.8 s (N = 10) and 23.8 ± 3.4 s (N = 10), respectively. When administered at 100 and 200 mg/kg, EOMV reduced the paw licking time for the second phase of the formalin test from the control value of 20.6 ± 2.1 s (N = 13) to 5.3 ± 2.2 s (N = 12) and 2.7 ± 1.2 s (N = 18), respectively. At 100 and 200 mg/kg, PO reduced this second phase to 8.3 ± 2.7 s (N = 12) and 3.0 ± 1.2 s (N = 10), respectively. This effect of EOMV and PO was not reversed by naloxone. EOMV and PO had no significant effect on the first phase of the formalin test. As evaluated by the hot-plate and tail immersion test, EOMV and PO, at doses up to 200 mg/kg, showed no analgesic activity. These results show that EOMV and PO have antinociceptive activity and suggest that this effect is probably an indirect anti-inflammatory effect, which does not involve the central nervous system.

Ochratoxin A in Brazilian green coffee

Ochratoxin A is a nephrotoxic, teratogenic and imunotoxic compound produced by Aspergillus and Penicillium spp. It is a suspected carcinogen to humans and it is carcinogenic to rats. Recently it has drawn attention because it has been found in coffee and it has been the object of regulation by coffee importing countries. Brazil is the largest coffee producing country and its largest consumer. In order to conduct an initial assessment of the situation of the coffee produced in the country and offered to its population, one hundred and thirty two samples of Brazilian green coffee from 5 producing states (Minas Gerais, Paraná, São Paulo, Espírito Santo and Bahia) and destined for the home market, were collected at sales points at the cities of Londrina and Santos, Brazil, and analyzed for ochratoxin A. The toxin was isolated in immunoaffinity columns and quantified by HPLC with florescence detection. The limit of detection was 0.7ng/g and the average RSD for duplicates of the samples was 11%. Twenty seven samples were found contaminated with the toxin and the average concentration for the contaminated samples was 7.1ng/g ochratoxin A. Neither the total number of defects nor the number of specific defects according to the Brazilian coffee classification system (black, partly -- black, sour, stinkers-black, stinkers-green, pod beans) showed any relation to the contamination of the samples with ochratoxin A.

Survey on ochratoxin A in Brazilian green coffee destined for exports

The presence of ochratoxin A (OTA) in foods has led some countries to establish regulatory limits. Although coffee is not a major source of OTA in human consumption, the European Community (EC) may establish limits in the near future, with possible economic impact on producing countries. This study measured the OTA content with HPLC in 37 samples of Brazilian green coffee exclusive destined to the export market and also verified a possible relation between coffee defects and OTA content. The results showed an OTA concentration ranging from < 0.16ng/g (detection limit) to 6.24ng/g (average of 3.20ng/g) for 37 samples. Of the five samples observed for defects, toxin content of sound beans ranged from 0.22 to 0.80ng/g (average 0.46ng/g) and of defective beans from 0.42 to 17.46 (average 4.52ng/g). Morphological differences among sound and defective beans showed no susceptibility for mould invasion under optical microscopy observation. One black bean depicted the presence of mould and spores on observation under Scanning Electron Microscope (SEM). According to this investigation, Brazilian green coffee for export complies with most limits in place.

Effect of processing and roasting on the antioxidant activity of coffee brews

The aim of this work was to evaluate the effect of processing and roasting on the antioxidant activity of coffee brews. Brews prepared with light, medium and dark roasted coffees were analyzed. The pH, total solids content, polyphenols content, reducing substances and chlorogenic acids content were determined. The antioxidant activity of aqueous extracts, the guaicol decolorizing and the capacity to inhibit lipid peroxidation were also analyzed. The antioxidant activity of coffee brews were concentration-dependent. A progressive antioxidant activity and polyphenols content was observed decreasing with roasting. The light roasted coffee showed the highest antioxidant activity and dark roasted coffee showed the lowest antioxidant activity. The results indicate that the ingestion of coffee brews prepared with light and medium roasted coffees might protect cells from oxidative stress damages.

Brazilian roasted coffee oil obtained by mechanical expelling: compositional analysis by GC-MS

A preliminary analysis by GC-MS comparing the mass spectrum of the compounds with the Wiley 275 L mass spectral data base was used to identify the fatty acids and mainly, some volatile compounds responsible for the flavor of the roasted coffee oil. The oil was obtained by mechanical expelling of Brazilian beans (Coffea arabica) roasted at 238ºC for 10 minutes. Different sample preparation methodologies such as headspace, adsorbent suction trapping and esterification were used. It was possible to identify pyrazines, pyridines, furan derivatives and other compounds not reported in the literature.

Nutrients in the cassava (Manihot esculenta Crantz) leaf meal at three ages of the plant

The high number of cassava cultivars adapted to many different regions provides a wide variation in the chemical composition of cassava leaves meal (CLM). Therefore, the contents of some nutrients in CLM from five cultivars at three ages of the plant were investigated in order to select the cultivars and ages with superior levels of these nutrients. When the plants were 12 months old, the highest levels of crude protein (CP), beta-carotene, iron, magnesium, phosphorus and sulfur were observed. The IAC 289-70 cv. showed the highest levels of magnesium, as well as considerable contents of CP, beta-carotene, iron, zinc and sulfur, which did not differ statistically from the cultivars showing the highest levels of these nutrients.

Antinutrients in the cassava (Manihot esculenta Crantz) leaf powder at three ages of the plant

In Brazil, the cassava leaf meal (CLM) has been used to strive against undernourishment because it is a high source of vitamins and minerals. However, the wide variation in the chemical composition of the different cultivars, as well as their antinutritional substances may be a restriction to their uses. The levels of some antinutrients in CLM from five cultivars at three ages of the plant (TAP) were investigated, in order to select the cultivars and plant ages that would be more appropriate for human consumption. The lowest contents of antinutrients were observed in the 12-month old plants, except for nitrate and hemagglutinin from which the lowest contents were found for the 17 month old ones. The cultivar IAC 289-70 had the lowest antinutrient levels, except for saponin and oxalate. Thus, the cultivar IAC 289-70 at 12 months is the most appropriate for human consumption.

Sensory evaluation of black instant coffee beverage with some volatile compounds present in aromatic oil from roasted coffee

The oil obtained from Brazilian roasted coffee by supercritical CO2 extraction shows considerable aromatic properties, mainly composed by five aromatic compounds, 2-methylpyrazine; 2-furfurylalcohol, 2,5-dimethylpyrazine; γ-butyrolactone and 2-furfurylacetate. Sensory analyses were used to verify the influence of a mixture of these important classes of aromatic coffee compounds (pyrazines, furans and lactones) and of the roasted coffee aromatic oil on the coffee aroma and flavour of black instant freeze and spray-dried coffee beverages. In the acceptance evaluation of the aroma, the samples prepared with freeze-dried instant coffee without the mixture of volatile compounds (sample 4) were not significantly different from the freeze-dried instant coffee in which the aromatic coffee oil was added (sample 5) and from the sample prepared with freeze-dried coffee in which the mixture of the five volatile was added (sample 3), coincidentally from the same drying process. Therefore, sample (3) did not differ from samples prepared with spray dried instant coffee without (sample 1) and to which (sample 2) the mixture of volatile was added. Therefore, with respect to this attribute, the addition of this mixture did not interfere in this drink acceptance. Taking into consideration the flavor, samples prepared with freeze-dried instant coffee in which the aromatic coffee oil was added (5) and the samples with (3) and without (4) the mixture of the five volatile was added did not differ significantly, however sample (4) did not differ from samples (1) and (2). Regarding this attribute, the addition of the aromatic oil of roasted coffee or a mixture of volatile in samples of freeze-dried instant coffee had a better acceptance than those dried by spray dryer (1) and (2). Thus, the enrichment of drinks with the aromatic oil of roasted coffee, or even with the mixture of the five components did not influence the consumer acceptance with respect to the aroma, but exerts influence with respect to flavour.