Antinociceptive and anti-inflammatory activity of the siaresinolic acid, a triterpene isolated from the leaves of Sabicea grisea Cham. & Schltdl. var. grisea.

In the present study, siaresinolic acid (siaresinol, SA) was isolated from the leaves of Sabicea grisea and studied to evaluate its antinociceptive and anti-inflammatory activity. The antinociceptive effect of SA was investigated in mice using different animal models to study pain. In the acetic acid-induced writhing test, intraperitoneal (i.p.) injection of SA (0.1, 1, and 10 mg/kg, i.p.) 1 h before a pain stimulus significantly reduced the nociceptive response (by 42.3, 68.2, and 70.9 %, respectively). Pretreatment with glibenclamide, but not with yohimbine, metoclopramide, ketanserin, or naloxone, restored the antinociceptive effect induced by SA in the writhing test, suggesting that the K(+)ATP channel pathway might be involved in its mechanism of action. In the formalin test, SA (1 mg/kg, i.p.) decreased licking time in the second phase only, thereby indicating an anti-inflammatory effect. In the hot plate test, there was no significant difference in nociceptive behavior. In the rota-rod test, it was verified that a high dose of SA (10 mg/kg, i.p.) did not affect the locomotor activity of mice. In the pleurisy model, induced by carrageenan, treatment with SA inhibited important events involved in inflammatory responses, namely leukocyte influx, plasma leakage, and increased inflammatory mediators (TNF-α, IL-1ß, and chemokine CXCL1), in the pleural exudate. Additionally, SA itself was not cytotoxic when evaluated using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in macrophages cultured for 24 h at concentrations ranging from 1 to 200 µg/mL. These results suggest, for the first time, that SA attenuates nociceptive behavior through mechanisms involving receptors for ATP-dependent potassium channels, in addition to suppressing acute inflammatory responses.

Isolation of a dihydrobenzofuran lignan, icariside E4, with an antinociceptive effect from Tabebuia roseo-alba (Ridley) Sandwith (Bignoniaceae) bark.

The antinociceptive activity of icariside E4, a dihydrobenzofuran-type lignan isolated from Tabebuia roseo-alba (Ridley) Sandwith (Bignoniaceae) bark, was evaluated in mice by using chemical and thermal models of nociception. Intraperitoneal (i.p.) administration of crude T. roseo-alba bark extract and its methanol fraction inhibited acetic acid-induced abdominal constriction in mice. Furthermore, i.p. administration of 0.1, 1, and 10 mg/kg of icariside E4 reduced the number of writhes evoked by acetic acid injection by 46.9, 82.3, and 66.6%, respectively. Icariside E4 administration had no effect in the first phase of the formalin test, but it reduced nociceptive behavior in the second phase as indicated by a reduction in the licking time. Icariside E4 did not modify thermal nociception in the hot-plate test model, suggesting that it had a peripheral antinociceptive action. The antinociceptive effect of icariside E4 in the writhing test was reversed by pre-administration of glibenclamide, but not of naloxone, atropine, yohimbine, or haloperidol. Together, these results indicated that the antinociceptive activity of icariside E4 from T. roseo-alba in models of chemical pain occurred through ATP-sensitive K(+) channel-dependent mechanisms.

Larvicidal activities and chemical composition of essential oils from Piper klotzschianum (Kunth) C. DC. (Piperaceae).

BACKGROUND: Volatile oils from fresh roots, stems, leaves and seeds of Piper klotzschianum (Piperaceae) were obtained by hydrodistillation and analysed by GC-FID and GC-MS. In total, 25 components, representing more than 95% of the examined oils, were identified. The essential oils were evaluated against Artemia salina Leach nauplii and fourth-instar Aedes aegypti larvae. RESULTS: The major chemical constituents that were identified from various parts of this plant were 1-butyl-3,4-methylenedioxybenzene and 2,4,5-trimethoxy-1-propenylbenzene in the root, 1-butyl-3,4-methylenedioxybenzene in the stems and leaves and 1-butyl-3,4-methylenedioxybenzene, limonene and α-phellandrene in the seeds. The biological activities of these essential oils generally exhibited high toxicity against A. salina, with LC50 values that ranged from 7.06 to 15.43 µg mL(-1), and significant larvicidal activity against fourth-instar A. aegypti larvae was observed in the essential oils from the seeds (LC50 of 13.27 µg mL(-1)) and roots (LC50 of 10.0 µg mL(-1)) of the plant. CONCLUSION: The present study indicates that both essential oil of P. klotzsdhianum and the isolate 1-butyl-3,4-methylenedioxybenzene are potential resources for A. aegypti larva control. This is the first report of the biological activities of the oil and isolated compound.

Antinociceptive and anti-inflammatory effects of octacosanol from the leaves of Sabicea grisea var. grisea in mice.

Sabicea species are used in the Amazon for treatment of fever and malaria, which suggests that its chemical constituents may have some effect on pain and inflammation. Phytochemical analysis of the hexane fraction obtained from the crude ethanol extract from Sabicea grisea var. grisea Cham. & Schltdl (Rubiaceae), an endemic plant in Brazil, resulted in the isolation of octacosanol. This study investigated the antinociceptive and anti-inflammatory effects of the octacosanol in different experimental models. The crude ethanolic extract and hexane fraction obtained from the leaves of S. grisea produced an inhibition of acetic acid-induced pain. Moreover, octacosanol isolated from the hexane fraction produced a significant inhibition of pain response elicited by acetic acid. Pre-treatment with yohimbine, an alpha 2-adrenergic receptor antagonist, notably reversed the antinociceptive activity induced by octacosanol in the abdominal constriction test. Furthermore, mice treated with octacosanol did not exhibit any behavioral alteration during the hot plate and rota-rod tests, indicating non-participation of the supraspinal components in the modulation of pain by octacosanol with no motor abnormality. In the formalin test, octacosanol did not inhibit the licking time in first phase (neurogenic pain), but significantly inhibited the licking time in second phase (inflammatory pain) of mice. The anti-inflammatory effect of octacosanol was evaluated using carrageenan-induced pleurisy. The octacosanol significantly reduced the total leukocyte count and neutrophils influx, as well as TNF-α levels in the carrageenan-induced pleurisy. This study revealed that the mechanism responsible for the antinociceptive and anti-inflammatory effects of the octacosanol appears to be partly associated with an inhibition of alpha 2-adrenergic transmission and an inhibition of pathways dependent on pro-inflammatory cytokines. Finally, these results demonstrated that the octacosanol from the leaves of S. grisea possesses antinociceptive and anti-inflammatory activities, which could be of relevance for the pharmacological control of pain and inflammatory processes.

Modulation of inflammatory processes by leaves extract from Clusia nemorosa both in vitro and in vivo animal models.

The present study was carried out to investigate the anti-inflammatory effect of the hexane extract of the leaves from Clusia nemorosa G. Mey, called HECn, using carrageenan-induced mice pleurisy and cotton pellet-induced mice granuloma. Additionally, the ability of HECn to affect both neutrophil migration as viability was investigated by use of the Boyden chamber assay and flow cytometry, respectively. The HECn significantly inhibited exudation, total leukocytes and neutrophils influx, as well as TNFα levels in carrageenan-induced pleurisy. However, the extract not suppressed the granulomatous tissue formation in the cotton pellet-induced granuloma test. Experiments performed in vitro revealed that HECn on human neutrophils inhibited a dose-dependent manner the CXCL1-induced neutrophil chemotaxis. Furthermore, HECn also inhibited the chemoattraction of human neutrophils induced by formyl-methionyl-leucyl-phenylalanine (fMLP), leukotriene B4 (LTB4) and platelet activating factor (PAF) in a Boyden chamber. However, this same treatment not was able to induce apoptosis. The results obtained in this study showed that the extract from leaves of C. nemorosa possess a potent inhibitory activity in acute model of inflammation, being the effects mediated, in part, by inhibition of neutrophil responsiveness. These results indicate that C. nemorosa could be a good source for anti-inflammatory compounds.

A new iridoid from Guettarda grazielae M.R.V. Barbosa (Rubiaceae).

Chromatographic fractionation of the chloroform extracts from the stem bark and stems of Guettarda grazielae resulted in the isolation of a new iridoid (guettardodiol, 1) and the secoiridoid sarracenin (2), described for the first time in this genus. The structural elucidation of these compounds was based on spectroscopic analyses (IR, MS as well as 1-D and 2-D NMR experiments).

Determination of the phenolic content and antioxidant potential of crude extracts and isolated compounds from leaves of Cordia multispicata and Tournefortia bicolor.

In this work, the total phenolic content and antioxidant activity of extracts and four flavonoids isolated from leaves of two Boraginaceae species (Cordia multispicata Cham. and Tournefortia bicolor Sw.) were evaluated using Folin-Ciocalteu reagent, DPPH free radical scavenging and inhibition of peroxidation of linoleic acid by FTC method. For comparison, ascorbic acid, alpha-tocopherol and BHT were used. In general, extracts from T. bicolor (68.8 +/- 0.001 to > 1000 mg/g) showed higher phenolic content than C. multispicata (66.1 +/- 0.009 to 231 +/- 0.07 mg/g), and also scavenged radicals (IC(50) 12.8 +/- 2.5 to 437 +/- 3.5 mg/L) and inhibited lipid peroxide formation (IC(50) 51.2 +/- 2.29 to 89 +/- 0.59 mg/L). For these extracts a good correlation between the phenolic content and antioxidant activity was observed, suggesting that T. bicolor is richer in phenolic compounds and that it could serve as a new source of natural antioxidants or nutraceuticals with potential applications. Chromatographic procedures monitored by antioxidant assays afforded seven compounds, which were identified by spectral analyses (IR, MS and 1D and 2D NMR) and comparison with reported data as being trans-phytol (1), taraxerol (2), 3,7,4'-trimethoxyflavone (3), 5,3'-dihydroxy-3,7,4'-trimethoxyflavone (4), quercetin (5), tiliroside (6), and rutin (7). Compounds (4-7) were also evaluated and were effective as DPPH quenching (IC(50) 7.7 +/- 3.6 to 79.3 +/- 3.4 mg/L) and as inhibition of lipid peroxidation (IC(50) 80.1 +/- 0.98 to 88.7 +/- 3.62 mg/L). This is the first report on the total phenolic content, radical-scavenging and antioxidant activities of these species.

Larvicidal activity of 94 extracts from ten plant species of northeastern of Brazil against Aedes aegypti L. (Diptera: Culicidae).

In an effort to find effective and affordable ways to control of Aedes aegypti L. (Diptera: Culicidae), the larvicidal activities of 94 extracts from ten plant species belonging to eight families [Guettarda grazielae and Spermacoce verticillata (Rubiaceae), Coccoloba mollis and Triplaris americana (Polygonaceae), Eschweilera ovata (Lecytidaceae), Merremia aegyptia (Convolvulaceae), Ouratea nitida (Ochnnaceae), Protium heptaphyllum (Burseraceae), Rourea doniana (Connaraceae), and Tovomita brevistaminea (Guttiferae)], widely found in the northeast of Brazil, were initially screened at 250 microg/mL. Nineteen of the 94 extracts from six plant species (C. mollis, G. grazielae, M. aegyptia, R. doniana, S. verticillata, and T. americana) showed significant activity (>75% mortality) against the fourth instar larvae. Some of these extracts showed 100% mosquito larvae mortality, with LD(50) values lower 200 microg/mL. When compared to synthetic insecticide Temephos (LD(50) 8.7 microg/mL), two of them, hexane (LD(50) 12.1 microg/mL) and ethyl acetate (LD(50) 51.6 microg/mL) extracts from stems of R. doniana and G. grazielae, respectively, were the most effective. The isolation and purification of these extracts are in progress and evaluation of these compounds will be needed to identify the active component.

Studies on the antimicrobial activity and brine shrimp toxicity of Zeyheria tuberculosa (Vell.) Bur. (Bignoniaceae) extracts and their main constituents.

BACKGROUND: Due to the indiscriminate use of antimicrobial drugs, the emergence of human pathogenic microorganisms resistant to major classes of antibiotics has been increased and has caused many clinical problems in the treatment of infectious diseases. Thus, the aim of this study was to evaluate for the first time the in vitro antimicrobial activity and brine shrimp lethality of extracts and isolated compounds from Zeyheria tuberculosa (Vell.) Bur., a species used in Brazilian folk medicine for treatment of cancer and skin diseases. METHODS: Using the disc diffusion method, bioautography assay and brine shrimp toxicity test (Artemia salina Leach), we studied the antimicrobial activity and lethality of extracts and isolated compounds against three microorganisms strains, including Gram-positive (Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa) bacteria and yeasts (Candida albicans). RESULTS: In this study, the extracts inhibited S. aureus (8.0 +/- 0.0 to 14.0 +/- 0.0 mm) and C. albicans (15.3 +/- 0.68 to 25.6 +/- 0.4 mm) growth. In the brine shrimp test, only two of them showed toxic effects (LC50 29.55 to 398.05 microg/mL) and some extracts were non-toxic or showed weak lethality (LC50 705.02 to > 1000 microg/mL). From these extracts, four flavones [5,6,7,8-tetramethoxyflavone (1), 5,6,7-trimethoxyflavone (2), 4'-hydroxy-5,6,7,8-tetramethoxyflavone (3), and 4'-hydroxy-5,6,7-trimethoxyflavone (4)] were isolated through bioassay-guided fractionation and identified based on the 1D and 2D NMR spectral data. By bioautography assays, compounds 1 [S. aureus (16.0 +/- 0.0 mm) and C. albicans (20.0 +/- 0.0 mm)] and 3 [S. aureus (10.3 +/- 0.6 mm) and C. albicans (19.7 +/- 0.6 mm)] inhibited both microorganisms while 2 inhibited only S. aureus (11.7 +/- 0.6 mm). Compound 4 did not restrain the growth of any tested microorganism. CONCLUSION: Our results showed that extracts and isolated flavones from Z. tuberculosa may be particularly useful against two pathogenic microorganisms, S. aureus and C. albicans. These results may justify the popular use this species since some fractions tested had antimicrobial activity and others showed significant toxic effects on brine shrimps. However, in order to evaluate possible clinical application in therapy of infectious diseases, further studies about the safety and toxicity of isolated compounds are needed.