Strychnos pseudoquina A. St. Hil.: a Brazilian medicinal plant with promising in vitro antiherpes activity

AIMS

To investigate the anti-HSV and anti-inflammatory effects of a standardized ethyl acetate extract (SEAE) prepared with the stem bark of Strychnos pseudoquina, along with two isolated compounds: quercetin 3-O-methyl ether (3MQ) and strychnobiflavone (SBF).

METHODS AND RESULTS

The mechanisms of action were evaluated by different methodological strategies. SEAE and SBF affected the early stages of viral infection and reduced HSV-1 protein expression. Both flavonoids elicited a concentration-dependent inhibition of monocyte chemoattractant protein-1 (MCP-1), whereas 3MQ reduced the chemokine release more significantly than SBF. Conversely, both compounds stimulated the production of the cytokines TNF-α and IL-1-β in LPS-stimulated cells, especially at the intermediate and the highest tested concentrations.

CONCLUSIONS

SEAE and SBF interfered with various steps of HSV replication cycle, mainly adsorption, postadsorption and penetration, as well as with β and γ viral proteins expression; moreover, a direct inactivation of viral particles was observed. Besides, both flavonoids inhibited MCP-1 selectively, a feature that may be beneficial for the development of new anti-HSV agents.

SIGNIFICANCE AND IMPACT OF THE STUDY

The results indicated that the samples present anti-HSV and anti-inflammatory activities, at different levels, which is an interesting feature since cold and genital sores are accompanied by an inflammation process.

In vitro and in vivo action of Piptadenia viridiflora (Kunth) Benth against Haemonchus contortus in sheep

Anthelminthic resistant populations of Haemonchus contortus are a major problem in sheep rearing, but plant extracts may offer viable alternative treatments. In our preliminary studies, Piptadenia viridiflora was frequently selected by sheep grazing in the Cerrado. The present research evaluated its in vitro and in vivo anthelmintic activity. The HPLC chromatograms of P. viridiflora aqueous extract (AE) and ethanolic extract (EE) showed the presence of flavonoids. The total condensed tannin (proanthocyanidin) was 0.2 and 1.01% in AE and EE, respectively. In an egg hatching inhibition (EHI) test, the LC90 of AE was 2.4mg/mL, and, of EE, was 2.1mg/mL. After tannin extraction, higher EHI and lower LC90 were observed. In a larval development inhibition test, the LC90 of AE was 13.66mg/g of fecal culture. The highest dose of AE administered to mice (203.0mg/kg bw) was well tolerated, suggesting low toxicity. In vivo, AE was orally administered to lambs at 283mg/kg bw, and, at weeks one, two, and three post-treatment, the mean fecal egg count (FEC) was significantly lower than in untreated lambs (P<0.05). Blood parameters were normal and similar in untreated and treated sheep. For all lamb groups, the mean total serum protein was significantly higher at week two post-treatment than at other evaluated periods (P<0.05). Piptadenia viridiflora extracts had low condensed tannin content and exhibited high anthelminthic efficacy in vitro and significantly reduced FEC. Tannins were not shown to be the principal components affecting EHI, hence it is necessary to isolate and characterize the principal active P. viridiflora compounds, and to assess their possible synergism.

Characterization and cytotoxic activity of sulfated derivatives of polysaccharides from Agaricus brasiliensis

Agaricus brasiliensis cell-wall polysaccharides isolated from fruiting body (FR) and mycelium (MI) and their respective sulfated derivatives (FR-S and MI-S) were chemically characterized using elemental analysis, TLC, FT-IR, NMR, HPLC, and thermal analysis. Cytotoxic activity was evaluated against A549 tumor cells by MTT and sulforhodamine assays. The average molecular weight (Mw) of FR and MI was estimated to be 609 and 310 kDa, respectively. FR-S (127 kDa) and MI-S (86 kDa) had lower Mw, probably due to hydrolysis occurring during the sulfation reaction. FR-S and MI-S presented ~14% sulfur content in elemental analysis. Sulfation of samples was characterized by the appearance of two new absorption bands at 1253 and 810 cm(-1) in the infrared spectra, related to S=O and C-S-O sulfate groups, respectively. Through (1)H and (13)C NMR analysis FR-S was characterized as a (1→6)-(1→3)-β-D-glucan fully sulfated at C-4 and C-6 terminal and partially sulfated at C-6 of (1→3)-β-D-glucan moiety. MI-S was shown to be a (1→3)-β-D-gluco-(1→2)-β-D-mannan, partially sulfated at C-2, C-3, C-4, and C-6, and fully sulfated at C-6 of the terminal residues. The combination of high degree of sulfation and low molecular weight was correlated with the increased cytotoxic activity (48 h of treatment) of both FR-S (EC₅₀=605.6 μg/mL) and MI-S (EC₅₀=342.1 μg/mL) compared to the non-sulfated polysaccharides FR and MI (EC₅₀>1500 μg/mL).

Hancornia speciosa Gomes induces hypotensive effect through inhibition of ACE and increase on NO

ETHNOPHARMACOLOGICAL RELEVANCE

The leaves of Hancornia speciosa Gomes are popularly used in Brazil to treat diabetes and hypertension. Cardiovascular diseases are the main cause of death worldwide and their incidences are increasing in Brazilian population. The present study aimed to investigate the hypotensive effect and the mechanism of action of Hancornia speciosa Gomes.

METHODS

A fraction of the ethanolic extract of leaves from Hancornia speciosa (SFH) was obtained and standardized by its content on rutin, bornesitol and quinic acid. Systolic blood pressure (SBP) of normotensive mice was measured by tail plethysmography. SFH was given orally and SBP was monitored for 5h. Angiotensin-converting enzyme (ACE) inhibitor activity of SFH (1mg/kg) or captopril (10mg/kg) was measured by colorimetric methods. Serum nitrite levels were measured by spectrophotometry.

RESULTS

SFH induced a dose-dependent hypotensive effect in normotensive mice. The serum activity of ACE and the level of angiotensin II were significantly reduced by SFH and by captopril. Administration of SFH induced a significant increase on plasmatic level of nitrites and the systemic inhibition of nitric oxide synthase by L-NAME (20mg/kg) reduced the hypotensive effect of SFH.

CONCLUSIONS

The present work demonstrated that Hancornia speciosa has a potent hypotensive effect in normotensive mice. The inhibition of ACE leading to reduction on angiotensin II and increase on NO levels might account for the hypotensive effect. These results support the use of Hancornia speciosa by traditional medicine as antihypertensive.

ACE inhibition by astilbin isolated from Erythroxylum gonocladum (Mart.) O.E. Schulz

Erythroxylum species have several traditional uses in different countries, including the treatment of hypertension. The ethanol extract from E. gonocladum aerial parts, a species endemic to the Brazilian cerrado, elicited a concentration-dependent inhibition of angiotensin converting enzyme (ACE) (pIC(50)=4.53+/-0.05). Extract fractionation led to the isolation of two compounds, whose structures were assigned by spectrometric data as astilbin and beta-sitosterol, along with a mixture of palmitic, stearic and linolenic acids. This is the first report on the occurrence of these compounds on E. gonocladum. Astilbin promoted significant ACE inhibition in vitro (pIC(50)=5.86+/-0.33) and its activity did not differ from captopril, when both compounds were assayed at 10 microM concentration.

Oestrogen and progesterone receptor gene expression in canine oocytes and cumulus cells throughout the oestrous cycle

The aim of this research was to analyze oestrogen receptor-alpha (ERalpha), ERbeta and progesterone receptor (PR) gene expression in the canine oocyte and cumulus cells throughout the oestrous cycle. Ovaries from 38 bitches were recovered after ovariohysterectomy and sliced. The phase of the oestrous cycle was determined by vaginal cytology, vaginoscopy and serum hormonal measurements. Oocytes were mechanically denuded by repeated pipetting. For each phase of the cycle, a sample was composed by a pool of 50 oocytes (sample number: prooestrus = 3, oestrus = 8, dioestrus = 5 and anoestrus = 5) or a pool of cumulus cells (prooestrus = 4, oestrus = 7, dioestrus = 4 and anoestrus = 6). Oocyte and cumulus cells' total RNA was isolated and reverse transcription was conducted to perform real-time PCR. Oestrogen receptor-alpha was expressed throughout the cycle in the oocyte (33.33%, 25.0%, 20.0% and 60.0% for prooestrus, oestrus, dioestrus and anoestrus, respectively) and cumulus cells (50.0%, 47.14%, 25.0% and 66.67% for prooestrus, oestrus, dioestrus and anoestrus, respectively). In the oocyte, the ERbeta was also expressed in all phases of the cycle (33.33%, 50.0%, 20.0% and 60.0% for prooestrus, oestrus, dioestrus and anoestrus, respectively), whereas in cumulus cells, ERbeta was only expressed during prooestrus (50%) and oestrus (14.29%). Interestingly, while the oocyte PR was not detected in any phase of the cycle, this receptor was expressed during prooestrus (50%), oestrus (42.86%) and anoestrus (16.67%) in cumulus cells. In conclusion, canine oocytes express ERalpha and ERbeta throughout the oestrous cycle, however, there is a lack of PR expression in all these phases. Moreover, in cumulus cells, only ERalpha was expressed throughout the oestrous cycle.

237 EXPRESSION OF THE GENES HSP 70.1, ZAR-1, AND MATER IN BOVINE OOCYTES SUBMITTED TO PREMATURATION AND/OR IN VITRO MATURATION

The present study aimed to assess the transcripts for the proteins that embryos require, histone 2a (H2a-FZ), heat shock 70 kDa protein 1A (HSP 70.1), zygote arrest 1 (ZAR-1), and maternal antigen (MATER), in bovine oocytes submitted to prematuration (PM) culture and/or in vitro maturation (IVM). Follicles (2–6 mm diameter) were aspirated from slaughterhouse-derived ovaries. Oocytes were selected and randomly distributed among treatments. For PM, oocytes were cultured 24 h in TCM-199 medium supplemented with 10 µm butyrolactone I, 0.2 mm pyruvate, and 10 µg mL–1 gentamicin (BGV group). Part of the prematured oocytes were washed and transferred to IVM culture (BMII group). For IVM, oocytes were cultured in TCM-199 supplemented with 10% FCS, 5.0 µg mL–1 LH, 0.5 µg mL–1 FSH, 0.2 mm pyruvate, and 10 µg mL–1 gentamicin for 22 h. As controls one group of oocytes was collected immediately after aspiration (GV group) and another group was matured in vitro (MII group) without undergoing prematuration. All cultures were carried out in 100-µL droplets of culture medium under mineral oil at 38.5�C and 5% CO2 in air. Oocytes from each treatment were denuded and frozen at 80�C (3 pools of 200 oocytes) in PBS with 0.1% polyvinyl alcohol (PVA) and 1 UI µL–1 RNase inhibitor. RNA was extracted using the RNeasy Protect Kit (Qiagen, S�o Paulo, Brazil) according to the manufacturer's instructions. The extracted RNA was used for reverse transcription by the enzyme Improm-II Reverse Transcriptase (Promega, Madison, WI, USA) according to the manufacturer's instructions. cDNA was produced in a thermocycler for 60 min at 42�C, followed by warming to 70�C for 15 min and cooling to 4�C for freezing at –20�C. Relative quantification of the transcripts for the genes H2a-FZ, HSP 70.1, ZAR-1, and MATER was performed by real-time PCR using the SYBR GREEN Kit (Applied Biosystems do Brasil, Sao Paulo, Brazil) according to manufacturer's instructions. Data were analyzed by the REST� software (Relative Expression Software Tool; Pfaffl et al. 2002 Nucl. Acids Res. 30, e36) 2005 BETA V1.9.9; a level of significance of 5% was considered to show differences among transcripts using H2a-FZ to normalize data. No differences were observed (P < 0.05) for the transcripts HSP 70.1, ZAR-1, and MATER, respectively, when comparing GV (1.0, 1.0, and 1.0), MII (0.37 � 0.1, 0.37 � 0.05, and 0.43 � 0.1), and GV with BGV (0.43 � 0.15, 0.54 � 0.2, and 0.33 � 0.25). However, a difference was detected (P < 0.05) between BGV (1.0, 1.0, and 1.0) and BMII (0.17 � 0.1, 0.13 � 0.05, and 0.3 � 0.2), but not between (P > 0.05) MII (1.0, 1.0, and 1.0) and BMII (0.52 � 0.25, 0.5 � 0.1, and 0.6 � 0.25) for transcripts HSP 70.1, ZAR-1, and MATER, respectively. A reduction in transcripts in group BMII may influence oocyte competence, reducing embryo development and/or quality.

Evolution of suiform aromatases: ancestral duplication with conservation of tissue-specific expression in the collared peccary (Pecari tayassu)

Aromatase cytochrome P450 (P450arom), the enzyme that catalyzes estrogen synthesis, is required for successful reproduction and is encoded by a single copy gene (CYP19) in most mammals. However, pigs and their distant suiform relatives the peccaries experienced CYP19 duplication. Here, the evolutionary origin of CYP19 duplication, and the evolution of the gene paralogs, was explored further in collared peccaries (Pecari tayassu). Exons IV and V, and the intervening intron, representing duplicated CYP19 genes, were cloned and sequenced from collared peccary, pig, and hippopotamus. Sequence alignment and analysis identified a gene conversion in collared peccary with a breakpoint 102 base pairs (bp) upstream of exon V. Phylogenetic analyses of nucleotide and amino acid sequence upstream of the breakpoint supported a tree in which one peccary sequence was orthologous with the porcine gonadal gene. Cloning and sequencing of tissue transcripts, using reverse-transcriptase polymerase chain reaction techniques (RT-PCR), confirmed that the gonadal ortholog was expressed in collared peccary testis. Orthology of the other genomic sequence with the porcine placental gene was not resolved, but its placenta-specific expression in collared peccary was confirmed by similar transcript analysis. Immunoblot and enzyme activity in collared peccary testes demonstrated much lower levels of P450arom than in pig testis. Collared peccary placental P450arom expression also seemed much lower than pigs. Thus, suiform CYP19 genes arose from an ancestral duplication that has maintained gonad- and placenta-specific expression, but at lower levels in peccaries than pigs, perhaps facilitating the emergence of different reproductive strategies as Suiformes diverged and evolved.

Antinociceptive effect from Davilla elliptica hydroalcoholic extract

Davilla elliptica St Hill (Dilleniaceae) is widely used for multiple purposes in Brazil. The aim of this study was to verify the pharmacological support of this folk use and evaluate its use as antinociceptive. The hydroalcoholic extract of the stems (100-1000 mg/kg, p.o.) induced reduction of response in the formalin test inflammatory phase in mice. This antinociceptive effect does not involve the opioidergic pathway since it was not reverted by pre-treatment with naloxone nor due to myorelaxant activity since it did not affect rota-rod and tail-flick performance. Our results indicate a participation of the nitrergic pathway and may be of particular potential importance in clinical medicine, in view of the current interest in the assessment of new medicines originated from plants.

Endothelium-dependent vasodilation induced by Hancornia speciosa in rat superior mesenteric artery

The vasodilator effect of the ethanolic extract of leaves from Hancornia speciosa Gomes (HSE) was evaluated in superior mesenteric artery rings. HSE produced a concentration-dependent vasodilation (IC50 = 10.8 +/- 4.0 microg/mL) in arterial rings pre-contracted with phenylephrine, which was completely abolished in endothelium-denuded vessels. Endothelium-dependent vasodilation induced by HSE was strongly reduced by L-NAME (100 microM), a nitric oxide (NO) synthase inhibitor, but neither by atropine, a muscarinic receptor antagonist (1 microM), nor by indomethacin (10 microM), a cyclooxygenase inhibitor. In rings pre-contracted with 80 mM KCl, the vasodilator effect of HSE was shifted to the right and was completely abolished in the presence of L-NAME (100 microM). Similar effects were obtained in mesenteric rings pre-contracted with phenylephrine in the presence of KCl 25 mM alone or in addition to 100 microM L-NAME. In addition, BaCl2 (1 mM) dramatically reduced the vasodilation induced by HSE. Together, these findings led us to conclude that HSE induces an endothelium-dependent vasodilation in rat mesenteric artery, by a mechanism dependent on NO, on the activation of potassium channels and endothelium-derived hyperpolarizing factor release. Rutin, identified as a major peak in the HPLC fingerprint obtained for HSE, might contribute for the observed vasodilator effect, since it was able to induce an endothelium-dependent vasodilation in rat superior mesenteric arteries.

Effects of the Brazilian phytopharmaceutical product Ierobina on lipid metabolism and intestinal tonus

Ierobina is a Brazilian phytopharmaceutical product indicated for the treatment of dyspepsia. It contains the hydroethanolic extracts of Solanum paniculatum L. (Solanaceae), Remijia ferruginea D.C. (Rubiaceae), Jacaranda caroba D.C. (Bignoniaceae) and Erythraea centaurium (L.) Borkh. (Gentianaceae), species traditionally used to treat gastrointestinal disorders. The effect of Ierobina on the digestive system was investigated in rats fed with normal or high-fat (HF) diets, at doses of 2.16, 4.32 and 8.64 mg/kg. The product did not affect the plasmatic levels of glucose, total cholesterol and HDL-cholesterol in the evaluated doses, whereas the triacylglycerol (TAG) concentration showed a dose-dependent increase in HF-fed animals. TAG-rich lipoprotein uptake, estimated by measuring total lipoprotein lipase activity in epididymal adipose tissue, was accompanied by TAG increase in HF-fed rats, after Ierobina administration. The product also induced a concentration-dependent relaxant effect on spontaneous ileum contractions and on the rat ileum pre-contracted with carbachol. Together, these results support the indication of Ierobina as an anti-dyspeptic agent.

Validation of a colorimetric assay for the in vitro screening of inhibitors of angiotensin-converting enzyme (ACE) from plant extracts

A new method for the in vitro screening of plant extracts with potential angiotensin-converting enzyme (ACE) inhibitory activity is proposed. The method is based on the cleavage of the substrate hippuryl-glycyl-glycine by ACE and subsequent reaction with trinitrobenzenesulfonic acid to form 2,4,6-trinitrophenyl-glycyl-glycine, whose absorbance is determined at 415 nm in a microtitre plate reader. Rabbit lung dehydrated by acetone was employed as an enzyme source. Validation of the method showed satisfactory intra-day (CV = 7.63%) and inter-day precision (CV = 13.61%), recovery (97-102.1%), sensitivity (IC50 = 14.1 nmol/l) and linearity in the range 7.5-120 mmol/l of glycyl-glycine (r2 = 0.9921). Besides, the method showed good correlation with a HPLC assay already established for the screening of ACE inhibitors (r = 0.9935 and 0.9034, respectively, for captopril solutions and for plant extracts). The method involves only inexpensive reagents and apparatus.

Antibacterial activity of Brazilian propolis and fractions against oral anaerobic bacteria

Propolis collected from a cerrado area in Minas Gerais State, Brazil, was subjected to chromatography on silica gel column and to partition between immiscible solvents. Propolis aqueous-ethanolic extract and fractions obtained were tested for inhibitory activity against periodontitis-causing bacteria. All of the assayed bacterium species were susceptible to propolis extract. The two fractionation methodologies yielded fractions which were active against bacteria, with minimum inhibitory concentrations (MIC) ranging from 64 to 1024 microg/ml. TLC and HPLC analyses of the extract and of active fractions showed the presence of phenolic compounds of varied polarity. None of the assayed fractions was more active than the extract, suggesting that the antibacterial activity is probably due to the synergistic effect of several compounds.

HPLC quantitation of kaurane diterpenes in Xylopia species

Xylopia frutescens is a tree native to the Brazilian Amazon whose seeds are rich in kaurenoic acid, a diterpene that showed in vitro activity against Trypanosoma cruzi. Aiming to find out alternative sources for kaurenoic acid, the content of some kaurane diterpenes was evaluated in X. aromatica and X. brasiliensis, species occurring in the Cerrado area of Minas Gerais, and also in X. frutescens. A reversed phase HPLC isocratic method was developed and validated to perform the assays. Kaurenoic acid was found to be the most abundant diterpene within the analyzed species, with a 3.16+/-0.97% content in the seeds of X. frutescens, which also presented the highest amount of xylopic acid (1.09+/-0.33%). The highest concentration of 16-alpha-hydroxykauranoic acid (1.96+/-1.58%) was found in the stems of X. aromatica.

Screening Brazilian plant species for in vitro inhibition of 5-lipoxygenase

Plants from the Brazilian flora were evaluated for the inhibition of 5-lipoxygenase. The species were selected based on their traditional use and on a chemosystematic approach. In total, 19 species belonging to 13 families have been investigated. Hedychium coronarium J. Koenig (Zingiberaceae), Xylopia frutescens Aubl. (Annonaceae) and Hymenaea courbaril L. (Leguminosae) presented a high 5-lipoxygenase inhibitory activity. Some hypothesis about the nature of the active compounds are discussed, based on reports of the chemical constitution of these species or other species from the same botanical family.

Isolation of cardenolides from a Brazilian cultivar of Digitalis lanata by rotation locular counter-current chromatography

Cardenolides from a Brazilian cultivar of Digitalis lanata were isolated by rotation locular countercurrent chromatography (RLCC), employing dichloromethane-methanol-water (5:6:4, v/v) as the solvent system. Highly pure lanatoside C was obtained from the Digitalis lanata hydromethanolic extract, pre-purified either by silica gel or reversed-phase chromatography.