Chemical Structure and Localization of Levan, the Predominant Fructan Type in Underground Systems of Gomphrena marginata (Amaranthaceae).

Gomphrena marginata Seub. (Amaranthaceae) is an endemic species from Brazilian campos rupestres with a fructan accumulating underground reserve system. Analyses of high performance anion exchange chromatography (HPAEC-PAD) revealed the presence of the soluble carbohydrates glucose, fructose, sucrose, 1-kestose, 6-kestose, nystose and fructans with degree of polymerization (DP) up to approximately 40 fructose units. Data of 1H and 13C Nuclear Magnetic Resonance (NMR) spectroscopy, including Heteronuclear Single-Quantum Correlation (HSQC) and Heteronuclear Multiple-Bonds Correlation (HMBC) showed the presence of ß (2,6) linkages, characteristic of the linear molecule of levan-type fructan(2,6). These results confirmed previous studies suggesting that the reserve carbohydrate in the underground system of this species was levan-type fructans, similar to that of G. macrocephala. Structural analyses of the thickened underground system using light microscopy revealed a mixed origin system consisting mainly of a gemmiferous tuberous root with the upper region formed by short branched stems, both presenting vascular cylinders with unusual growth patterns. Fructan spherocrystals were visualized under polarized light and scanning electron microscopy (SEM) mostly in the cortex and vascular cylinder in both thickened stem and root. In addition to data reported in the literature concerning the occurrence of fructans in the Amaranthaceae, the results presented here suggest that fructans are a trait in this family while the levan-type fructan prevail in Gomphrena species.

Phytochemical Characterization of Terminalia catappa Linn. Extracts and Their antifungal Activities against Candida spp.

Terminalia catappa Linn bark is used to treat dysentery by various populations in Southeast Asian countries, and its leaves have also been used in traditional medicine to treat hepatitis in India and the Philippines. Here, the antifungal actions of crude hydro-alcoholic extract (TcHE) and fractions from T. catappa leaves were assessed via the agar diffusion and microdilution tests on Candida reference strains and clinical isolates from patients with acquired immunodeficiency syndrome (AIDS). Additionally, the potential cytotoxic effects of TcHE were assessed on cultured human peripheral blood mononuclear cells (PBMC). T. catappa fractions and sub-fractions were analyzed by gas chromatography coupled to mass spectrometry with electron impact (GC/MS/EI), high-performance liquid chromatography coupled to mass spectrometry "electrospray" ionization in positive mode (HPLC/MS/MS/ESI+) and hydrogen nuclear magnetic resonance (1HNMR). TcHE and its fractions were able to inhibit the growth of all tested Candida strains with the n-butanol (FBuOH) fraction presenting the best antifungal activity. Testing of different FBuOH sub-fractions (SF) showed that SF10 was the most active against Candida spp. Fractioning of SF10 demonstrated that 5 out of its 15 sub-fractions were active against Candida spp., with SF10.5 presenting the highest activity. Chemical analysis of SF10 detected hydrolysable tannins (punicalin, punicalagin), gallic acid and flavonoid C-glycosides. Overall, the results showed that T. catappa L. leaf extract, fractions and sub-fractions were antifungal against Candida spp. and may be useful to treat diseases caused by this fungus.

Involvement of monoaminergic systems in the antidepressant-like properties of Lafoensia pacari A. St. Hil.

ETHNOPHARMACOLOGICAL RELEVANCE: Lafoensia pacari A. St.-Hil. (Lythraceae), known popularly as "pacari" or "mangaba-brava" is popularly used in the state of Goiás, Brazil. The stem bark or leaves are used to treat cancer, gastric disorders, inflammation and as a tonic to treat loss of enthusiasm. AIM OF THE STUDY: Previous results suggest that the ethanol:water 7:3 extract of the stem bark of L. pacari (PEx) has antidepressant-like activity in male mice. Our aim was to perform the PEx׳s bioguided fractionation and evaluate the monoaminergic system involvement in the antidepressant effect as well as progress in the study of L. pacari mechanism of action. MATERIAL AND METHODS: Mice (30-35g) orally treated (24, 5 and 1h) with PEx (100, 300 or 1000mg/kg), chloroform (ChloF-70mg/kg), ethyl acetate (180mg/kg), n-butanol (370mg/kg) and aqueous (1g/kg) fractions were submitted to the forced swimming test. To assess the mechanism of action, different groups of mice were pretreated with p-chlorophenylalanine (PCPA-100mg/kg, 4 days, i.p.) and alpha-methyl-p-tyrosine (AMPT-100mg/kg, 4h, i.p.) to assess the involvement of serotoninergic and catecholaminergic systems in the ChloF effects, respectively. A putative in vitro inhibition of monoamine oxidase (MAO) activity as well as the ex vivo hippocampal brain-derived neurotrophic factor (BDNF) quantification were carried out. Phytochemical screening, spectroscopy and chromatography analysis were used for identification of compounds present in ChloF. RESULTS AND DISCUSSION: After the fractionation, the ChloF 70mg/kg was the most active fraction, reducing the immobility time by 22%. Pre-treatments with both PCPA and AMPT abolished the ChloF effects, suggesting that ChloF antidepressant-like effect is dependent on serotonergic and catecholaminergic systems. ChloF did not inhibited MAO-A or MAO-B activity, excluding this as possible mechanism of action. ChloF augmented hippocampal BDNF level, which could be accounted for its antidepressant-like effect. Phytochemical screening showed the presence of saponins, tannins, steroids and triterpene in the PEx, and the presence of triterpene and steroids in ChloF. The spectroscopy and chromatography analysis identified lupeol, ß-sitosterol and stigmasterol in ChloF. CONCLUSION: ChloF is the fraction that better retained the crude extract active constituents. ChloF presents antidepressant-like effect that involves both serotonergic and catecholaminergic systems without inhibiting MAO enzymatic activity; this fraction also increases the hippocampal BDNF levels.

Biologically active compounds from cyanobacteria extracts: in vivo and in vitro aspects

An investigation was directed towards the antiacetylcholinesterase activity of the acid aqueous and methanolic extracts of five cyanobacterial taxa, which encompasses an enzymatic inhibition essay and the evaluation of the physiological responses of mice to cyanobacterial extracts along with toxicological observations. The strains Calothrix sp. CCIBt 3320, Tolypothrix sp. CCIBt 3321, Phormidium cf. amoenum CCIBt 3412, Phormidium sp. CCIBt 3265, and Geitlerinema splendidum CCIBt 3223 were from the São Paulo Botanical Institute Cyanobacterial Culture Collection and all of them showed inhibitory effect on acetylcholinesterase activity (in vitro) and caused systemic effects similar to those described for anticholinesterase drugs (in vivo). With the exception of G. splendidum and Tolypothrix sp. strains, all extracts produced reversible antiacetylcolinesterase effects in mice. Complementary histopathological studies were carried out on tissues from animals administered with Phormidium sp. and P. cf. amoenum.

Antiulcerogenic activity of the extracts of Struthanthus marginatus

The gastroprotective action of the aqueous extract (AE) and the hydroalcoholic extract obtained from the leaves of Struthanthus marginatus (Desr.) Blume, Loranthaceae, were performed with in vivo models in rodents using: ethanol, indomethacin or stress-induced ulcers, determination of gastric secretion and the mucus production. The scavenger activity of AE in vitro was tested by the DPPH method. The treatment with the extracts (125-1000 mg/kg) significantly inhibited ulcerative lesions in comparison with the negative control groups in all the models evaluated and demonstrated greater effectiveness of the aqueous extract. Regarding the model of gastric secretion, a reduction in volume of gastric juice and total acidity was observed, as well as an increase in the gastric pH. The treatment of rats raised the gastric mucus production. Significant DPPH scavenging activity was evident in the AE. No sign of toxicity was observed. These results show that S. marginatus possesses gastroprotective activity. There are indications that the mechanisms involved in anti-ulcer activity are related to a decrease in acid secretion and an increase in gastric mucus content. Also, there is evidence for the involvement of antioxidant activity in the gastroprotective mechanism.

Inhibition of the gastric H+,K+ -ATPase by plectrinone A, a diterpenoid isolated from Plectranthus barbatus Andrews.

This work assessed the mechanism underlying the antisecretory gastric acid effect of Plectranthus barbatus Andrews (Lamiaceae) and active constituents. Popularly known as "false-boldo", this plant is used in Brazilian folk medicine to treat gastrointestinal and hepatic ailments. The plant aqueous extract (AE) and isolated compounds were assayed in vivo in pylorus-ligated mice, and in vitro on acid secretion measured as [(14)C]-aminopyrine ([(14)C]-AP) accumulation in rabbit gastric glands and gastric H(+),K(+)-ATPase preparations. Injected into the duodenal lumen, the AE of the plant leaves (0.5 and 1.0 g/kg) decreased the volume (62 and 76%) and total acidity (23 and 50%) of gastric acid secretion in pylorus-ligated mice. Bioguided purification of the AE yielded an active fraction (IC(50)=24 microg/ml) that inhibited acid secretion in rabbit gastric glands with a potency 10 to 18 times greater than that of the originating extract, on both the basal and stimulated acid secretion by histamine (His) (1 microM) or bethanechol (100 microM). At the same concentrations the gastric H(+),K(+)-ATPase activity was also inhibited. The active constituent was chemically identified as the abietanoid dienedione plectrinone A which reduced the H(+),K(+)-ATPase activity with IC(50)=171 microM. The results indicate that inhibition of the gastric proton pump by this diterpenoid may account for the antisecretory acid effect and reputed anti ulcer activity of Plectranthus barbatus.

Analgesic activity of a triterpene isolated from Scoparia dulcis L. (vassourinha)

Analgesic and anti-inflammatory activities of water (WE) and ethanolic (EE) extracts of Scoparia dulcis L. were investigated in rats and mice, and compared to the effects induced by Glutinol, a triterpene isolated by purification of EE. Oral adminsitration (p.o.) of either WE or EE (up to 2 g/Kg) did not alter the normal spontaneous activity of mice and rats. The sleeping time induced by sodium pentobarbital (50 mg/Kg, i.p.) was prolonged by 2 fold in mice pretreated with 0.5 g/Kg EE, p.o. Neither extract altered the tail flick response of mice in immersion test, but previous administration of EE (0.5 g/Kg, p.o.) reduced writhings induced by 0.8% acetic acid (0.1 ml/10 g, i.p.) in mice by 47% EE (0.5 and 1 g/Kg, p.o.) inhibited the paw edema induced by carrageenan in rats by respectively 46% and 58% after 2 h, being ineffective on the paw edema induced by dextran. No significant analgesic or anti-edema effects were detected in animals pretreated with WE (1 g/Kg, p.o.). Administration of Glutinol (30 mg/Kg, p.o.) reduced writhing induced by acetic acid in mice by 40% and the carrageenan induced paw edema in rats by 73%. The results indicate that the analgesic activity of S dulcis L. may be explained by explained by an anti-inflammatory activity probably related to the triterpene Glutinol.