Myricitrin, a nitric oxide and protein kinase C inhibitor, exerts antipsychotic-like effects in animal models.

Myricitrin is a nitric oxide (NO) and protein kinase C (PKC) inhibitor that has central nervous system activity, including anxiolytic-like action. Nitric oxide inhibitors blocked the behavioral effects of apomorphine, suggesting an antipsychotic-like effect. Furthermore, PKC inhibition reduced psychotic symptoms in acute mania patients and blocked amphetamine-induced hyperlocomotion, suggesting a potential antipsychotic-like effect. The present study evaluated the effects of myricitrin in animal models that assess antipsychotic-like effects (apomorphine-induced stereotypy and climbing and the paw test) and extrapyramidal side effects (catalepsy test and paw test). Olanzapine was used as a positive control. 7-Nitroindazole (7-NI), a NOS inhibitor, and l-arginine, a NO precursor, were used to evaluate nitrergic modulation, and tamoxifen was used to test the effect of PKC inhibition. In mice, myricitrin dose-dependently and olanzapine blocked the stereotypy and climbing induced by apomorphine at doses that did not induce catalepsy. 7-Nitroindazole also blocked apomorphine-induced stereotypy and climbing, which were reversed by l-arginine pretreatment. l-arginine only attenuated the effects of myricitrin on apomorphine's effects. Tamoxifen also blocked apomorphine-induced stereotypy and climbing. In the paw test in rats, myricitrin and olanzapine increased hindlimb retraction time at doses that did not affect forelimb reaction time, whereas haloperidol affected both parameters at the same dose. Myricitrin did not induce catalepsy in the bar test. Tamoxifen did not affect hindlimb retraction time or forelimb retraction time, whereas 7-NI significantly increased hindlimb reaction time. Thus, myricitrin exhibited an antipsychotic-like profile at doses that did not induce catalepsy, and this effect may be related to nitrergic action.

Antifungal activities of compounds isolated from Piper abutiloides Kunth.

Piperaceae is a family of tropical plants known to have antifungal, antibacterial, tumour-inhibitory, antiviral, antioxidant, molluscicidal and leishmanicidal activities. In this work, extracts and fractions from aerial parts of Piper abutiloides (Piperaceae), a traditional medicinal plant, were evaluated against the fungal species Candida albicans, C. parapsilosis, C. krusei, C. glabrata, C. tropicalis, Cryptococcus neoformans and Sporothrix schenckii. The results have shown that the antifungal activity of this plant can be concentrated in the hexanic fraction after partitioning its hydroalcoholic extract between hexane and 90% aqueous methanol. The chromatographic fractionation of the bioactive part was monitored with a bioautographic assay using C. glabrata, and allowed the isolation of three antifungal compounds: pseudodillapiol, eupomatenoid-6 and conocarpan. These compounds presented different potencies against the fungi tested, with the strongest effect being observed for eupomatenoid-6 against C. glabrata, which presented a minimal inhibitory concentration value of 0.3 microg spot(-1). Conocarpan showed antifungal activity without apparent cytotoxic effect on normal human lymphocytes, as assessed by the proliferation assay with human peripheral blood mononuclear cells stimulated with phytohaemaglutinin. This work reveals for the first time the occurrence of these compounds in P. abutiloides and justifies further studies to clarify their mechanisms of action.

Antioxidant and anti-inflammatory effects of products from Croton celtidifolius Bailon on carrageenan-induced pleurisy in rats.

Croton celtidifolius Bailon, commonly known as Sangue-de-Adáve or Pau-Andrade, is a tree found in the Atlantic forest of southern Brazil. It has been popularly used for the treatment of inflammatory and ulcerative disorders. Phytochemical analysis demonstrated the presence of flavonoids and proanthocyanidins in an ethyl acetate fraction (EAF) from C. celtidifolius Bailon. In this study, we have evaluated the effects of EAF and its sub-fractions (35 and 63, catechin) on inflammatory (cell migration and plasma extravasation) and oxidative (lipid peroxidation, superoxide dismutase (SOD) activity and superoxide anion production) parameters in carrageenan-induced pleurisy in rats. NO production was also measured by nitrite/nitrate levels. EAF and sub-fraction 63 (63SF) showed anti-inflammatory activity, as indicated by a reduction in plasma extravasation and cell migration (mainly polymorphonuclear leukocytes) to the pleural cavity. Furthermore, EAF treatment decreased the production of superoxide radical anion by cells isolated from the pleural cavity, while it did not affect the nitrite/nitrate levels in exudates. The results show that C. celtidifolius contains substances with antioxidant and anti-inflammatory activity that, at least in part, act by a modulation of oxidative stress by phenolic compounds.

Trypanocidal activity of extracts from Brazilian Atlantic Rain Forest plant species.

The trypanocidal activity of crude hydro alcoholic extracts and several fractions of 13 plants from Brazilian Atlantic Rain Forest were tested in vitro against epimastigote and trypomastigote forms of Trypanosoma cruzi, the etiological agent of Chagas disease. Crude ethanol extracts with promising in vitro activity (DL50 between 5-10 microg/ml) against epimastigotes were fractionated by solvent partition and further tested against bloodstream form of the parasite. Activity against bloodstream parasites was observed in both dichloromethane and hexane fractions of Polygala sabulosa and P. paniculata.

Anti-inflammatory and antioxidant effects of Croton celtidifolius bark.

Croton celtidifolius Baill commonly known as "sangue-de-adave" is a tree found in the Atlantic Forest of south of Brazil, mainly in Santa Catarina. The bark and leaf infusions of this medicinal plant have been popularly used for the treatment of inflammatory diseases. In this study we evaluated the anti-inflammatory and antioxidant properties of crude extract (CE), aqueous fraction (AqF), ethyl acetate fraction (EAF), butanolic fraction (BuF) and catechin, gallocatechin and sub-fractions, 19SF, 35SF and 63SF that contained a mixture of proanthocyanidins and were derived from the EAF fraction. The CE, AqF, EAF, BuF, catechin and sub-fractions 35SF and 63SF reduced paw edema induced by carrageenan. The CE, fractions, sub-fractions and isolated compounds showed antioxidant properties in vitro, all were able to scavenge superoxide anions at a concentration of 100 microg ml(-1). The EAF, catechin and gallocatechin were most effective in the deoxyribose assay, IC50 0.69 (0.44-1.06), 0.20 (0.11-0.39), 0.55 (0.28-1.08) microg x ml(-1) respectively. The CE and other fractions and sub-fractions inhibited deoxyribose degradation up to 1 microg x ml(-1). In the hydrophobic system only AqF did not show lipid peroxidation inhibition. The CE, other fractions, sub-fractions and isolated compounds inhibited lipidid peroxidation only at a concentration of 100 microg x ml(-1). In summary, this study demonstrates that Croton celtidifolius bark has significant anti-inflammatory and antioxidant activity.

Monitoramento dos extratos brutos de espécies de Polygala (Polygalaceae) utilizando Artemia salina

Extratos de duas espécies de Polygala foram submetidos a um biomonitoramento utilizando o teste de toxicidade frente a Artemia salina, com a finalidade de detectar atividade citotóxica. Os resultados obtidos para o extrato bruto, frações hexânica e diclorometano de Polygala sabulosa Aw. Benn. mostraram-se promissores. No entanto, bioensaios mais específicos devem ser encorajados nos extratos vegetais que apresentam atividade diante deste bioensaio, a fim de confirmar estas conclusões.

Extracts of two species of Polygala were subjected to a bioscreening study to detect cytotoxic activity by the brine shrimp lethality bioassay. The results obtained for the crude extracts, hexanic and dichlorometane fractions of Polygala sabulosa Aw. Benn. were promising. These results suggest that in those plant extracts, which showed activity for this bioassay, more specific bioassays should be encouraged, in order to confirm these conclusions.

A new flavonol from leaves of Eugenia jambolana.

Leaves of Eugenia jambolana yielded the new flavonol, myricetin 3-O-(4"-acetyl)-alpha-L-rhamnopyranoside (1).

Triterpenes from the resin of Protium heptaphyllum.

From the neutral fraction of the resin of Protium heptaphyllum, a mixture of alpha- and beta-amyrin, a mixture of maniladiol and brein have been isolated as main components, and the novel 3 beta,24-dihydroxy-urs-12-ene (1), 3-oxo-20S-hydroxytaraxastane (2) and 3 beta,20S-dihydroxytaraxastane (3) as minor components. NMR data of the last three compounds are provided.

Antinociception caused by the extract of Hedyosmum brasiliense and its active principle, the sesquiterpene lactone 13-hydroxy-8,9-dehydroshizukanolide.

The hydroalcoholic extract (HE) obtained from stems and leaves of Hedyosmum brasiliense, given i.p., produced significant inhibition of acetic acid-induced abdominal constriction in mice, with a mean ID50 of 12.7 mg/kg. This effect installed rapidly (0.5 h) and lasted for up to 2 h. Given orally up to 1000 mg/kg, the HE was ineffective. When assessed in the formalin response the HE, given i.p., inhibited the first and second phase, with ID50s of 31.1 and 21.7 mg/kg for the first and the second phases, respectively. The HE also inhibited capsaicin-induced neurogenic pain with ID50 of 69.0 mg/kg, but, in contrast to morphine, failed to cause analgesia in either the tail-flick or hot-plate models of pain. In addition, its antinociception was not reversed by naloxone. The sesquiterpene lactone 13-hydroxy-8,9-dehydroshizukanolide, isolated from H. brasiliense and already reported in other plant species (given by i.p., i.t., or i.c.v. routes) exhibited graded antinociception against acetic-acid writhing and capsaicin-induced licking. Additionally, we have corrected some physico-chemical data already reported for this compound. It is concluded that both the extract and the sesquiterpene lactone isolated from H. brasiliense produced marked antinociception in different models of chemical pain. The site of action involved in the antinociception of the 13-hydroxy-8,9-dehydroshizukanolide remains unclear, but the opioid pathway seems unlikely to be involved in its action.

Chemical composition and antimicrobial activity of Croton urucurana Baillon (Euphorbiaceae).

In the methanolic extract of Croton urucurana Baillon (Euphorbiaceae) a number of known compounds, such as acetyl aleuritolic acid, stigmasterol, beta-sitosterol, campesterol, beta-sitosterol-O-glucoside, sonderianin, catechin and gallocatechin were isolated and identified by MS and NMR spectroscopy, HRGC and data from literature. The antibacterial activity of the aqueous-EtOH extract, some fractions of the methanolic extract and some of the isolated compounds, were tested against Staphylococcus aureus and Salmonella typhimurium. Acetyl aleuritolic acid exhibits the best minimum inhibitory concentration (MIC) against both Staphylococcus aureus and Salmonella typhimurium.

Mechanisms involved in the antinociceptive effect in mice of the hydroalcoholic extract of Siphocampylus verticillatus.

The antinociception caused by the hydroalcoholic extract of Siphocampylus verticillatus (Campanulaceae) has been investigated in chemical and thermal models of nociception in mice. We have also assessed some of the mechanisms underlying the antinociceptive effect of the extract. The hydroalcoholic extract of S. verticillatus (60-1000 mg kg-1, i.p. or p.o.) produced dose-related, significant and long-lasting (6 to 8 h) inhibition of acetic acid-induced abdominal constriction in mice, with ID50 values of 204 and approximately 1000 mg kg-1, respectively. In the formalin test, the extract (100-1000 mg kg-1), given either intraperitoneally or orally, resulted in graded inhibition of both phases of formalin-induced pain, being about 2- to 4-fold more potent in attenuating the second phase of the pain. The calculated mean ID50 (mg kg-1) values for the earlier and the later phases were: 491 and 186 and 640 and 441, respectively. In addition, the extract (60-1000 mg kg-1, i.p. or p.o.) caused marked and dose-related inhibition of capsaicin-induced neurogenic pain with mean ID50 values of 420 and 485 mg kg-1, respectively. The hydroalcoholic extract, at the same doses, did not significantly affect the performance of animals in the rota-rod test, nor did it have any analgesic effect in the tail-flick or hot-plate tests. The treatment of animals with naloxone (5 mg kg-1, s.c.) significantly reversed the analgesic effect of both morphine (5 mg kg-1, s.c.) and the extract (300 mg kg-1, i.p.) when assessed against acetic acid-induced abdominal constrictions. The treatment of animals with L-arginine (600 mg kg-1, i.p.) significantly attenuated the antinociceptive effects of NG-nitro-L-arginine (L-NOARG) (75 mg kg-1, i.p.), of the hydroalcoholic extract (600 mg kg-1, i.p.) or of morphine (5 mg kg-1, s.c.), when analysed against the formalin test. In addition, adrenalectomy of animals 7 days before the tests significantly reversed the antinociception caused by the hydroalcoholic extract (300 mg kg-1, i.p.) in the formalin-induced pain. These data show that the hydroalcoholic extract of S. verticillatus has significant and long-lasting oral antinociception when assessed against both neurogenic and inflammatory models of nociception in mice. The precise mechanism responsible for the analgesic effect of the extract still remains unclear, but a great part of this effect seems to be partly related to an opioid-like action and involvement of the L-arginine-nitric oxide pathway. Finally, the antinociception caused by the hydroalcoholic extract of S. verticillatus is modulated by adrenal hormones.

Antinociceptive properties of the hydroalcoholic extract and preliminary study of a xanthone isolated from Polygala cyparissias (Polygalaceae).

Polygala cyparissias (Polygalaceae) grows abundantly on Brazil's Atlantic coast, belonging to the typical underbrush vegetation of dunes and have been used in folk medicine for treatment of several diseases, such as disturbances of bowel and kidney. The hydroalcoholic extract of P. cyparissias (HE, 3 to 60 mg kg(-1), i.p. or 25 to 200 mg kg(-1), p.o.) produced significant and graded inhibition of acetic acid-induced abdominal constrictions, with mean ID50 values of 6 and 72 mg kg(-1), respectively. The HE (at this same range of doses) also produced dose-related inhibition of both the early and the late phase of formalin-induced licking. The calculated mean ID50 values for the early phase were: >60 and >200 mg kg(-1), while for the late phase they were 11 and 101 mg kg(-1), respectively, by i.p. and p.o. routes. The HE also caused dose-related inhibition of formalin-induced edema formation (P<0.01). The HE (3 to 60 mg kg(-1), i.p. or 50 to 200 mg kg(-1), p.o.) produced significant and dose-related inhibition of the neurogenic nociception caused by topical injection of capsaicin, with mean ID50 values of 12 and 71 mg kg(-1), respectively. Given orally, the HE (50 to 200 mg kg(-1)) prevented in a dose-dependent manner, bradykinin (3 nmol/paw) and substance P (10 nmol/paw)-induced hyperalgesia in the rat paw, with mean ED50 values of 122 and 121 mg kg(-1), respectively, but was ineffective in the hot-plate model of nociception. The antinociception caused by the HE, in contrast to that of morphine (5 mg kg(-1), s.c.), was not reversed by naloxone (5 mg kg(-1), i.p.) when assessed in the acetic acid writhing test. The HE, at antinociceptive doses, did not affect motor coordination of animals when assessed in the rota-rod model. The xanthone isolated from P. cyparissias, identified as 1,7-dihydroxy-2,3-dimethoxy xanthone (0.3 to 30 mg kg(-1), i.p.), produced dose-related inhibition of acetic acid-induced abdominal constriction, with mean ID50 value of 1.5 mg kg(-1). These data show that the active principle(s) present in the HE of P. cyparissias, elicited pronounced antinociception when assessed by i.p. or p.o. routes, against both inflammatory and neurogenic nociception, and was able to prevent bradykinin and substance P-induced hyperalgesia. Its precise mechanism of action still remains unclear.

Mechanisms involved in the contractile responses induced by the hydroalcoholic extract of Phyllanthus urinaria on the guinea pig isolated trachea: evidence for participation of tachykinins and influx of extracellular Ca2+ sensitive to ruthenium red.

1. The hydroalcoholic extract (HE) of stems, leaves and roots from P. urinaria (Euphorbiaceae) (1-3000 micrograms/ml), caused graded contraction in guinea pig trachea (GPT), being more effective in preparations without epithelium. 2. Response to HE was slightly affected by tetrodotoxin (0.3 microM) and nicardipine (1 microM), but was unaffected by w-conotoxin, atropine, mepyramine or staurosporine (all 1 microM). Indomethacin (3 microM) greatly inhibited HE contraction, but MK 571 (leukotriene D4 and E4 antagonist) caused partial inhibition; L-655,240 (thromboxane A2 antagonist) and WEB 2086 (PAF antagonist) (all 1 microM) were ineffective. 3. Response to HE was markedly inhibited in a Ca(2+)-free solution and was partially affected in GPT desensitized to capsaicin (10 microM). 4. Capsazepine (capsaicin antagonist, 3 microM) antagonized the contraction from capsaicin, leaving the response to HE unaffected. In contrast, ruthenium red (an ionic channel antagonist coupled to vanilloid receptors of capsaicin) (0.1-3 microM) caused graded and equipotent noncompetitive inhibition of HE- and capsaicin-induced contractions, but had no effect on carbachol- and prostaglandin E2-mediated responses. 5. FK 888 and SR 48968 (NK1 and NK2 receptor antagonists, respectively) (both 1 microM) antagonized, through a competitive mechanism, the contraction from SP and [beta-ala8]NKA (4-10) respectively, but antagonized, through a noncompetitive mechanism, HE-mediated contraction. 6. We concluded that contraction to HE in GPT is modulated by the epithelium, depends on the release of a cyclo-oxygenase metabolite, and relies largely upon an extracellular Ca2+ influx that is highly sensitive to ruthenium red, but is insensitive to L and N-type of voltage-sensitive Ca2+ channel antagonists. In addition, NK1 and NK2 tachykinins, but not vanilloid receptors, play an important role in mediating its response.

Chemical and preliminary analgesic evaluation of geraniin and furosin isolated from Phyllanthus sellowianus.

The present study describes the occurrence of two ellagitannins in the ethanolic extract of the leaves and stems of Phyllanthus sellowianus (Euphorbiaceae). Their preliminary antinociceptive properties were also evaluated. The two ellagitannins were identified on the basis of 1H- and 13C-NMR spectra data and by mixed co-TLC and co-HPLC injection with an authentic sample of furosin and geraniin. Preliminary pharmacological analysis revealed that both furosin and geraniin (3 to 30 mg/kg, i.p.), given 30 min before testing, exhibited significant and dose-related antinociceptive properties against acetic acid-induced abdominal constrictions in mice. Geraniin and furosin were about six- to seven-fold more potent at the ID50 level (micromol/kg) as analgesics than aspirin and acetaminophen, respectively, although they were less efficacious when compared with the standard drugs. These data extend our previous studies and indicate that the two ellagitannins isolated from P.sellowianus, identified as furosin and geraniin are, at least in part, responsible for the antinociceptive actions reported previously for the hydroalcoholic extract of P.sellowianus and other plants belonging to the genus Phyllanthus.

Antinociceptive properties of steroids isolated from Phyllanthus corcovadensis in mice.

The antinociceptive actions of the steroid compounds isolated from the leaves, stems, and roots of P. corcovadensis have been investigated in mice. Stigmasterol, stigmasterol acetate, beta-sitosterol, and aspirin (3-100 mk/kg, i.p.) inhibited, in a dose-related manner, acetic acid-induced abdominal constriction in mice with ID50s of 16, 11, 9, and 24 mg/kg, respectively. In the formalin test, stigmasterol and stigmasterol acetate (10-100 mg/kg, i.p.) caused graded inhibition of both the neurogenic (first phase) and inflammatory phases (second phase) of formalin-induced pain. However, both compounds were more effective in relation of the second phase of the formalin test with ID50 values of 26 and 41 mg/kg, respectively. Furthermore, both steroids failed to affect the edematogenic response of the formalin test. Given orally, stigmasterol and stigmasterol acetate (50-200 mg/kg) also exhibited significant though less potent analgesic action against both acetic acid- and formalin-induced nociception in mice. In addition, stigmasterol (up to 100 mg/kg, i.p.), in contrast to morphine (10 mg/kg, s.c.), had no analgesic effect in either tail-flick or hot-plate models. These findings suggest that stigmasterol and beta-sitosterol may account, at least in part, for the antinociceptive actions reported previously for the hydroalcoholic extract of Phyllanthus corcovadensis.

The competitive antagonistic effect of compounds from Mandevilla velutina on kinin-induced contractions of rat uterus and guinea-pig ileum in vitro.

1. Pure non-peptide compounds obtained in crystal form from the crude extract of the plant Mandevilla velutina (Apocynaceae) were analysed for their antagonistic effects on rat uterine and guinea-pig smooth muscle contractions induced by bradykinin (Bk), lisyl-bradykinin (L-Bk), acetylcholine (ACh), oxytocin and histamine, in vitro. 2. Pre-incubation of rat uterine muscle with compounds MV 8608, MV 8609, MV 8610, MV 8611 and MV 8612 (5 to 40 micrograms ml-1) caused parallel and concentration-dependent rightward displacements of the Bk concentration-response curves (1 to 1000 nM). Schild plots of these data were linear (correlation close to 1) and yielded nominal pA2 values (g ml-1) of 5.7, 5.6, 5.4, 5.7 and 5.3, respectively. Compounds MV 8608, MV 8611 and MV 8612 (5 to 20 micrograms ml-1) also caused concentration-dependent and parallel displacements to the right of the concentration-response curve to L-Bk (1 to 10,000 nM). The Schild plots were linear and furnished nominal pA2 values (g ml-1) of 5.4, 5.8 and 5.1, respectively. With the exception of the antagonist effect of compound MV 8606 against Bk-induced contraction, all compounds behaved as simple competitive kinin antagonists since the calculated slopes were not different from unity. 3. In the guinea-pig ileum, both MV 8608 and MV 8612 (5 to 20 micrograms ml-1), produced concentration-dependent rightward displacements of the concentration-response curve to Bk (0.1 to 1000 nM) when the experiments were performed in the presence but not in the absence of atropine (2.5 microM). However, in contrast to the result obtained in the rat uterus, compound MV 8608 also caused a significant reduction of the maximal response to Bk. The Schild plot for compound MV 8612 was linear (correlation close to unity) and furnished a nominal pA2 value (g ml-1) of 5.3 and a slope not different from unity. 4. In rat uterine muscle, compounds MV 8608 and MV 8612 at concentrations producing marked rightward displacements of the kinin concentration-response curves (10 and 20 micrograms ml-1), did not influence the uterine contractile response to oxytocin or ACh, indicating some selectivity towards kinin receptors. Similarly, compound MV 8612 (10 and 20 ygml 1) did not interfere with the sensitivities or the maximal responses to ACh and histamine in the guinea-pig ileum, whereas compound MV 8608 (10 and 20ug ml-1) caused a slight reduction of ACh- and histamine-induced maximal contractions, allied to decrease of the sensitivity to histamine at concentrations of 20pgml-1 or more. 5. These results extend our previous data, indicating the existence of several non-peptide compounds in the crude extract of Mandevilla velutina that act as simple, competitive, selective and reversible kinin receptor antagonists in the rat isolated uterus and guinea-pig ileum smooth muscle.

Kinin antagonist activity of compounds from Mandevilla velutina in the rat isolated uterus.

The effect of four semi-purified compounds obtained from Mandevilla velutina crude extract by silica gel chromatography fractionization were analysed for their inhibitory effects on uterine contractions induced by bradykinin (BK), lysylbradykinin (L-BK), acetylcholine (ACh) and oxytocin, in vitro. None of the compounds tested affected uterine tone. Pre-incubation for 20 min with fraction 12 (20 to 80 micrograms ml-1), isolated from M. velutina produced a parallel and concentration-dependent displacement to the right of the concentration-response curves for BK and L-BK (1 to 1000 nM). Schild plots of these data were linear (correlation close to unity) and yielded a nominal pA2 value (as g ml-1) of 5.1 and 4.9, respectively, and the values of the slopes were not significantly different from unity. Fraction 11 (10 to 40 micrograms ml-1) also produced a parallel and concentration-dependent displacement to the right of the BK concentration-response curve. The Schild plot gave a mean pA2 value (g ml-1) of 5.4 and a slope not significantly different from unity. Fraction 12 did not influence the uterine contractile responses induced by ACh (0.1 to 100 microM) and oxytocin (0.01 to 30 miu ml-1) at concentrations less than 80 micrograms ml-1. Fraction 16 (20 to 80 micrograms ml-1) antagonized the action of BK only at concentrations greater than 40 micrograms ml-1, whereas fraction 5 (20 to 80 micrograms ml-1) was completely inactive against BK-induced responses. 5 As observed previously with the crude extract, the onset of the BK antagonistic action of these compounds was rapid and completely reversible following intermittent washing of the preparation for 30-60 min. 6 These results indicate the existence of at least two compounds in the crude extract of Mandevilla velutina that act as competitive and selective kinin antagonists on the isolated uterus of the rat.