Molluscicidal and cercaricidal activities of the essential oil of Dysphania ambrosioides (L.) Mosyakin & Clemants: Implications for the control of schistosomiasis.

Schistosomiasis is one of the most important tropical diseases. A fundamental strategy to control its spread is the use of natural products against its vectors, which are snails of the genus Biomphalaria. The present study evaluated the chemical composition, the molluscicidal and cercaricidal effects, and the ecotoxicity of the essential oil from the aerial parts of Dysphania ambrosioides (L.) Mosyakin & Clemants (DAEO). The essential oil was obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS). Molluscicidal and cercaricidal activities were determined by the immersion method. Environmental toxicity was assessed from bioassays using Artemia salina larvae and Danio rerio fish. DAEO presented a 0.8% yield. The GC-MS analysis revealed the predominance of hydrocarbon monoterpenes in the oil. A total of 32 constituents was identified, with α-terpinene (50.69%) being the major compound, followed by p-cymene (13.27%) and ascaridole (10.26%). DAEO was active against adult Biomphalaria glabrata snails and demonstrated lethal effect against Schistosoma mansoni cercariae, with LC50 values of 25.2 (22.7-27.8) and 62.4 (61.8-62.9) µg/mL, respectively. Regarding toxicity to non-target aquatic organisms, the oil showed LC50 values of 86.9 (84.7-87.6) and 18.6 µg/mL (15.5-22.8) for A. salina and D. rerio, respectively. DAEO proved to be a promising natural product for the control of schistosomiasis, acting on both the vectors and the etiological agent of the disease. However, the use of the oil is safer in transmission sites where there are no non-target organisms, as it has showed toxicity to D. rerio fish.

Proliferation of human adipose tissue-derived stem cells stimulated by oil rich in thymol of Lippia origanoides.

PURPOSE: To evaluate the effects of this thymol-rich oil in the proliferation of human adipose tissue-derived stem cells. METHODS: Stem cells were isolated from human adipose tissue by liposuction. After the first passage, cells were cultivated in triplicate for three days in control medium and medium supplemented with three oil samples (1.0 µg/mL, 5.0 µg/mL, and 25.0 µg/mL). Cells were analyzed by the MTT assay at passage 1 (P1), and cell proliferation of control and 1 µg/mL groups was determined with a hemocytometer at P2 and P3. RESULTS: Viability of the essential oil-treated cells was significantly higher than the control group at P1 (p = 0.0008). The treatment with the oil, at a concentration of 1 µg/mL, led to increases of 24.8% at P1 and 43.0% at P3 in the rate of cell proliferation compared with control cells. CONCLUSION: Supplementing culture medium with essential oil of Lippia origanoides increased cell proliferation, especially at later passages.

Proliferation of human adipose tissue-derived stem cells stimulated by oil rich in thymol of Lippia origanoides

Abstract Purpose: To evaluate the effects of this thymol-rich oil in the proliferation of human adipose tissue-derived stem cells. Methods: Stem cells were isolated from human adipose tissue by liposuction. After the first passage, cells were cultivated in triplicate for three days in control medium and medium supplemented with three oil samples (1.0 μg/mL, 5.0 μg/mL, and 25.0 μg/mL). Cells were analyzed by the MTT assay at passage 1 (P1), and cell proliferation of control and 1 μg/mL groups was determined with a hemocytometer at P2 and P3. Results: Viability of the essential oil-treated cells was significantly higher than the control group at P1 (p = 0.0008). The treatment with the oil, at a concentration of 1 µg/mL, led to increases of 24.8% at P1 and 43.0% at P3 in the rate of cell proliferation compared with control cells. Conclusion: Supplementing culture medium with essential oil of Lippia origanoides increased cell proliferation, especially at later passages.

Seasonal analysis and acaricidal activity of the thymol-type essential oil of Ocimum gratissimum and its major constituents against Rhipicephalus microplus (Acari: Ixodidae).

The tick Rhipicephalus microplus affects cattle health, with production loss in tropical and subtropical regions. Moreover, the use of commercial acaricides has been reduced due to the resistance of this parasite. Although alternatives such as plant bioactive molecules have been sought, essential oils present variations in their chemical constituents due to environmental factors, which can interfere with their acaricidal activity. The objective of the present study was to evaluate the seasonal influence of the essential oil of Ocimum gratissimum and its major constituents on acaricidal activity against R. microplus larvae. A high-yield essential oil of O. gratissimum and its major constituents were used, and a plant with a thymol-type oil was selected for seasonal analysis and acaricidal activity against R. microplus. Gas chromatography (GC) and GC-mass spectrometry (MS) were employed to identify 31 oil constituents (average yield of 6.26%). The main compounds were found to be thymol (33.4 to 47.9%), γ-terpinene (26.2 to 36.8%), and p-cymene (4.3 to 17.0%). Concerning acaricidal activity, the December (LC50 0.84 mg/mL) and September (LC50 1.58 mg/mL) oils obtained in the dry season were the most active, and assays performed with commercial standards revealed LC50 values of p-cymene, thymol, and γ-terpinene of 1.41, 1.81, and 3.08 mg/mL, respectively. Overall, lower acaricidal activities were found for oils produced from plants harvested in the rainy season. The results showed that seasonal variation in the chemical composition of the O. gratissimum essential oil influences its acaricidal activity. The seasonal variations in the thymol-type essential oil of O. gratissimum can represent an important strategy for the control of R. microplus.

Chemical composition and acaricide activity of an essential oil from a rare chemotype of Cinnamomum verum Presl on Rhipicephalus microplus (Acari: Ixodidae).

The Essential Oils (EOs) from the leaves of species Cinnamomum verum J. Presl are used in the pharmaceutical industry for their numerous biological activities. Currently, the main compound of C. verum EO is eugenol which has acaricidal activity; however, a rare chemotype with benzyl benzoate as the main component can be found. Benzyl benzoate is recognized as an acaricide; however, studies of the C. verum EOs benzyl benzoate chemotype on Rhipicephalus microplus were not reported. The aim of this study was to evaluate the acaricide activity of an EO from a rare chemotype of C. verum, as well as purified benzyl benzoate, against larvae and engorged females of R. microplus resistant to amidines and pyrethroids. The EO was extracted from C. verum leaves and the compounds present were identified using a gas phase chromatograph coupled to a mass spectrometer. Efficacy against R. microplus was assessed by the larval packet and the engorged female immersion tests. A rare chemotype of C. verum was found to produce EOs with benzyl benzoate (65.4%) as the main compound. The C. verum essential oil was 3.3 times more efficient on the R. microplus larvae than was benzyl benzoate. However, no differences were found on the R. microplus engorged females. This is the first report regarding the acaricidal activity of C. verum with chemotype benzyl benzoate, and this compound showed acaricidal activity on R. microplus larvae.

Cultivation of Guaco (Mikania laevigata Sch. Bip. ex Baker) in the Lower Amazon River and monitoring of coumarin, its principal active constituent / Cultivo do Guaco (Mikania laevigata Sch. Bip. ex Baker) no Baixo Rio Amazonas e monitoramento de cumarina, seu principal constituinte ativo

Mikania laevigata (Asteraceae) é popularmente usada no tratamento de doenças respiratórias, incluindo asma, bronquite e tosse. No Brasil, extratos de guaco são usados como produtos medicinais autorizados pela Agência Nacional de Vigilância Sanitária (ANVISA). No estudo, avaliou-se a adaptação e influência da variação sazonal do guaco, em um cultivo mantido em Santarém, Estado do Pará, Brasil; além do monitoramento da cumarina, seu principal constituinte ativo. No cultivo do guaco, as variáveis climáticas e o teor de cumarina foram avaliados mensalmente. A cumarina foi analisada por CCD (Cromatografia em Camada Delgada) e quantificada por HPLC (Cromatografia Liquida de Alta Eficiência) com base nos extratos hidroalcoólico e aquoso das folhas desidratadas. Na estação chuvosa (janeiro a julho), o guaco teve um crescimento homogêneo. Na estação de estiagem (agosto a novembro) houve perda das plantas que cresciam a pleno sol. O teor de cumarina foi detectado durante o desenvolvimento da planta, com níveis que variaram de 0,470 ± 0,01% a 0,886 ± 0,063%. O tempo da coleta não influenciou no teor de cumarina nas plantas cultivadas com 50% de sombra, tendo a média de 0,712% no extrato hidroalcoólico e 0,744% no extrato aquoso. Baseado nos resultados, em condições de sombreamento parcial, assegurou-se que o cultivo do guaco no Baixo Rio Amazonas pode ser replicado pelos pequenos agricultores, em seus Arranjos Produtivos Locais (APL) de plantas medicinais.(AU)

Mikania laevigata (Asteraceae) is popularly used in the treatment of respiratory diseases, including asthma, bronchitis, and cough. In Brazil, guaco extracts are used as medicinal products authorized by the National Health Surveillance Agency (ANVISA).In the study, it was evaluated the adaptation and the influence of the seasonal variation of guaco, in a cultivation held in Santarém, state of Pará, Brazil, and a monitoring of coumarin, its primary active constituent. In the growing of guaco, the climate variables, and the coumarin content were evaluated monthly. The coumarin was analyzed by TLC (Thin Layer Chromatography) and quantified by HPLC (High Performance Liquid Chromatography) from hydroalcoholic and aqueous extracts of dried leaves. In the rainy season (january-july), the guaco had a homogeneous growth. In the dry season (august to november), there was loss of plants grown in full sun. The coumarin content was detected throughout the development of the plant, with levels that varied from 0.470 ± 0.01% to 0.886 ± 0.063%. The time of collection does not influenced in the coumarin content of the plants grown with 50% shade, having the mean of 0.712% in the hydroalcoholic extract and 0.744% in the aqueous extract. Based on the results, in partial shade conditions, it was ensured that small farmers could replicate the cultivation of guaco in the Lower Amazon River, in their local productive arrangements of medicinal plants.(AU)

Chemical Composition and Larvicidal Activity of Essential Oils Extracted from Brazilian Legal Amazon Plants against Aedes aegypti L. (Diptera: Culicidae).

The mosquito Aedes aegypti L. (Diptera: Culicidae) is the major vector of dengue and chikungunya fever. The lack of effective therapies and vaccines for these diseases highlights the need for alternative strategies to control the spread of virus. Therefore, this study investigated the larvicidal potential of essential oils from common plant species obtained from the Chapada das Mesas National Park, Brazil, against third instar A. aegypti larvae. The chemical composition of these oils was determined by gas chromatography coupled to mass spectrometry. The essential oils of Eugenia piauhiensis Vellaff., Myrcia erythroxylon O. Berg, Psidium myrsinites DC., and Siparuna camporum (Tul.) A. DC. were observed to be mainly composed of sesquiterpene hydrocarbons. The essential oil of Lippia gracilis Schauer was composed of oxygenated monoterpenes. Four of the five tested oils were effective against the A. aegypti larvae, with the lethal concentration (LC50) ranging from 230 to 292 mg/L after 24 h of exposure. Overall, this work demonstrated the possibility of developing larvicidal products against A. aegypti by using essential oils from the flora of the Brazilian Legal Amazon. This in turn demonstrates the potential of using natural resources for the control of disease vectors.

Linalool-rich rosewood oil induces vago-vagal bradycardic and depressor reflex in rats.

Cardiovascular effects of the linalool-rich essential oil of Aniba rosaeodora (here named as EOAR) in normotensive rats were investigated. In anesthetized rats, intravenous (i.v.) injection of EOAR induced dose-dependent biphasic hypotension and bradycardia. Emphasis was given to the first phase (phase 1) of the cardiovascular effects, which is rapid (onset time of 1-3 s) and not observed in animals submitted to bilateral vagotomy or selective blockade of neural conduction of vagal C-fibre afferents by perineural treatment with capsaicin. Phase 1 was also absent when EOAR was directly injected into the left ventricle injection, but it was unaltered by i.v. pretreatment with capsazepine, ondansetron or HC030031. In conscious rats, EOAR induced rapid and monophasic hypotensive and bradycardiac (phase 1) effects that were abolished by i.v. methylatropine. In endothelium-intact aortic rings, EOAR fully relaxed phenylephrine-induced contractions in a concentration-dependent manner. The present findings reveal that phase 1 of the bradycardiac and depressor responses induced by EOAR has a vago-vagal reflex origin resulting from the vagal pulmonary afferents stimulation. Such phenomenon appears not to involve the recruitment of C-fibre afferents expressing 5HT3 receptors or the two chemosensory ion channels TRPV1 and TRPA1 . Phase 2 hypotensive response appears resulting from a direct vasodilatory action.

Eugenia uniflora L. Essential Oil as a Potential Anti-Leishmania Agent: Effects on Leishmania amazonensis and Possible Mechanisms of Action.

Eugenia uniflora L. is a member of the Myrtaceae family and is commonly known as Brazilian cherry tree. In this study, we evaluated the chemical composition of Eugenia uniflora L. essential oil (EuEO) by using gas chromatography-mass spectrometry (GC-MS) and assessed its anti-Leishmania activity. We also explored the potential mechanisms of action and cytotoxicity of EuEO. Thirty-two compounds were identified, which constituted 92.65% of the total oil composition. The most abundant components were sesquiterpenes (91.92%), with curzerene (47.3%), γ -elemene (14.25%), and trans- ß -elemenone (10.4%) being the major constituents. The bioactivity shown by EuEO against promastigotes (IC50, 3.04 µ g·mL(-1)) and amastigotes (IC50, 1.92 µ g·mL(-1)) suggested significant anti-Leishmania activity. In the cytotoxicity determination, EuEO was 20 times more toxic to amastigotes than to macrophages. Hemolytic activity was 63.22% at the highest concentration tested (400 µ g·mL(-1)); however, there appeared to be no toxicity at 50 µ g·mL(-1). While the data show that EuEO activity is not mediated by nitric oxide production, they do suggest that macrophage activation may be involved in EuEO anti-Leishmania activity, as evidenced by increases in both the phagocytic capacity and the lysosomal activity. More studies are needed to determine in vivo activity as well as additional mechanisms of the anti-Leishmania activity.

Vasorelaxant effects of 1-nitro-2-phenylethane, the main constituent of the essential oil of Aniba canelilla, in superior mesenteric arteries from spontaneously hypertensive rats.

The present study investigated the mechanisms underlying the vasorelaxant effects of the essential oil of Aniba canelilla (EOAC) and its main constituent 1-nitro-2-phenylethane (NP) in isolated superior mesenteric artery from spontaneously hypertensive rats (SHRs). At 0.1-1000 µg/mL, EOAC and NP relaxed SMA preparations pre-contracted with 75 mMKCl with IC(50) (geometric mean [95% confidence interval]) values of 294.19 [158.20-94.64] and 501.27 [378.60-624.00] µg/mL, respectively); or with phenylephrine (PHE) (IC(50)s=11.07 [6.40-15.68] and 7.91 [4.08-11.74) µg/mL, respectively). All these effects were reversible and remained unaltered by vascular endothelium removal. In preparations maintained under Ca(2+)-free conditions, EOAC and NP (both at 600 µg/mL) reduced the PHE-, but not the caffeine-induced contraction. In Ca(2+)-free and high K(+) (75 mM) medium, the contractions produced by CaCl(2) or BaCl(2) were reduced or even abolished by EOAC and NP at 100 and 600 µg/mL, respectively. EOAC and NP (both at 10-1000 µg/mL) also relaxed the contraction evoked by phorbol dibutyrate (IC(50)=52.66 [10.82-94.64] and 39.13 [31.55-46.72] µg/mL, respectively). It is concluded that NP has a myogenic endothelium-independent vasorelaxant effects and appears to be the active principle of the EOAC. Vasorelaxant effect induced by both EOAC and NP is preferential to receptor-activated pathways and it appears to occur intracellularly more than a superficial action restricted to the membrane environment such as a simple blocking activity on a given receptor or ion channel.

Cardiovascular effects of 1-nitro-2-phenylethane, the main constituent of the essential oil of Aniba canelilla, in spontaneously hypertensive rats.

This study investigated the cardiovascular responses to the essential oil of Aniba canelilla (EOAC) and its main constituent 1-nitro-2-phenylethane (NP) in spontaneously hypertensive rats (SHRs). In anesthetized SHRs, intravenous (i.v.) bolus injections of EOAC (1-20 mg/kg) or NP (1-10 mg/kg) elicited dose-dependent hypotensive and bradycardiac effects, which were characterized in two periods (phases 1 and 2). The first rapid component (phase 1) evoked by EOAC and NP both at 10 mg/kg was absent after left ventricle injection, fully abolished by bilateral vagotomy and perineural treatment of both cervical vagus nerves with capsaicin (250 µg/mL) while remained unaltered by i.v. pretreatment with capsazepine (1 mg/kg) or ondansetron (30 µg/kg). In conscious SHRs, NP (5 and 10 mg/kg, i.v.) evoked rapid hypotensive and bradycardiac effects (phase 1) that were fully abolished by methylatropine (1 mg/kg, i.v.) pretreatment. In rat endothelium-containing mesenteric preparations, increasing concentrations (0.1-1000 µg/mL) of EOAC and NP relaxed the phenylephrine-induced contraction in a concentration-dependent manner. It is concluded that NP induces a vago-vagal bradycardiac and depressor reflex (phase 1) that apparently results from the stimulation of vagal pulmonary rather than cardiac C-fiber afferents. This effect does not appear to involve activation of either vanilloid TPRV(1) or 5-HT(3) receptors located on vagal sensory nerves. The phase 2 hypotensive response to i.v. NP seems to result, at least in part, from its direct vasodilatory effect on the peripheral smooth muscle. All in vivo and in vitro effects of EOAC are mostly attributed to the actions of its main constituent NP.

1-Nitro-2-phenylethane, the main constituent of the essential oil of Aniba canelilla, elicits a vago-vagal bradycardiac and depressor reflex in normotensive rats.

Previously, it was shown that intravenous (i.v.) treatment with the essential oil of Aniba canelilla (EOAC) elicited a hypotensive response that is due to active vascular relaxation rather than to the withdrawal of sympathetic tone. The present study investigated mechanisms underlying the cardiovascular responses to 1-nitro-2-phenylethane, the main constituent of the EOAC. In pentobarbital-anesthetized normotensive rats, 1-nitro-2-phenylethane (1-10mg/kg, i.v.) elicited dose-dependent hypotensive and bradycardiac effects which were characterized in two periods (phases 1 and 2). The first rapid component (phase 1) evoked by 1-nitro-2-phenylethane (10mg/kg) was fully abolished by bilateral vagotomy, perineural treatment of both cervical vagus nerves with capsaicin (250 microg/ml) and was absent after left ventricle injection. However, pretreatment with capsazepine (1mg/kg, i.v.) or ondansetron (30 microg/kg, i.v.) did not alter phase 1 of the cardiovascular responses to 1-nitro-2-phenylethane (10mg/kg, i.v.). In conscious rats, 1-nitro-2-phenylethane (1-10mg/kg, i.v.) evoked rapid hypotensive and bradycardiac (phase 1) effects that were fully abolished by methylatropine (1mg/kg, i.v.). It is concluded that 1-nitro-2-phenylethane induces a vago-vagal bradycardiac and depressor reflex (phase 1) that apparently results from the stimulation of vagal pulmonary rather than cardiac C-fiber afferents. The transduction mechanism of the 1-nitro-2-phenylethane excitation of C-fiber endings is not fully understood and does not appear to involve activation of either Vanilloid TPRV(1) or 5-HT(3) receptors. The phase 2 hypotensive response to 1-nitro-2-phenylethane seems to result, at least in part, from a direct vasodilatory effect since 1-nitro-2-phenylethane (1-300 microg/ml) induced a concentration-dependent reduction of phenylephrine-induced contraction in rat endothelium-containing aorta preparations.

Rosewood oil induces sedation and inhibits compound action potential in rodents.

AIM OF THE STUDY: Aniba rosaeodora is an aromatic plant which has been used in Brazil folk medicine due to its sedative effect. Therefore, the purpose of the present study was to evaluate the sedative effect of linalool-rich rosewood oil in mice. In addition we sought to investigate the linalool-rich oil effects on the isolated nerve using the single sucrose-gap technique. MATERIALS AND METHODS: Sedative effect was determined by measuring the potentiation of the pentobarbital-induced sleeping time. The compound action potential amplitude was evaluated as a way to detect changes in excitability of the isolated nerve. RESULTS: The results showed that administration of rosewood oil at the doses of 200 and 300 mg/kg significantly decreased latency and increased the duration of sleeping time. On the other hand, the dose of 100 mg/kg potentiated significantly the pentobarbital action decreasing pentobarbital latency time and increasing pentobarbital sleeping time. In addition, the effect of linalool-rich rosewood oil on the isolated nerve of the rat was also investigated through the single sucrose-gap technique. The amplitude of the action potential decreased almost 100% when it was incubated for 30 min at 100 microg/ml. CONCLUSIONS: From this study, it is suggested a sedative effect of linalool-rich rosewood oil that could, at least in part, be explained by the reduction in action potential amplitude that provokes a decrease in neuronal excitability.

Cardiovascular effects of the essential oil of Aniba canelilla bark in normotensive rats.

Cardiovascular effects of intravenous (i.v.) treatment with the essential oil of the bark of Aniba canelilla (EOAC) were investigated in normotensive rats. In both pentobarbital-anesthetized and conscious rats, i.v. bolus injections of EOAC (1 to 20 mg/kg) elicited similar and dose-dependent hypotension and bradycardia. Pretreatment of anesthetized rats with bilateral vagotomy significantly reduced the bradycardia without affecting the hypotension. In conscious rats, pretreatment with hexamethonium (30 mg/kg, i.v.) significantly reduced the EOAC-induced bradycardia without affecting the hypotension. The opposite effect was observed after i.v. pretreatment with the nitric oxide synthase inhibitor, N-nitro-L-arginine methyl esther (L-NAME, 20 mg/kg). However, both EOAC-induced hypotension and bradycardia were significantly reduced by pretreatment with methylatropine (1 mg/kg, i.v.). In rat endothelium-containing aorta preparations, EOAC (1-600 microg/mL) induced a concentration-dependent reduction of potassium (60 mM)-induced contraction [IC50 (geometric mean+/-95% confidence interval)=64.5 (45.6-91.2) microg/mL)], an effect that was significantly reduced by the addition of atropine (10 microM) in the perfusion medium [IC50=109.5 (72.5-165.4) microg/mL)]. Furthermore, the vasorelaxant effects of the EOAC were also but significantly reduced [IC50=139.1 (105.2-183.9) microg/mL)] by removal of the vascular endothelium. Furthermore, the CaCl2-induced contractions in calcium-free medium were reduced and even fully abolished by EOAC (100 and 600 microg/mL), respectively. However, EOAC (600 microg/mL) was without significant effect on caffeine-induced contractions in calcium-free medium. These data show that i.v. treatment of rats with EOAC induces dose-dependent hypotension and bradycardia, which occurred independently. The bradycardia appears mainly dependent upon the presence of an operational and functional parasympathetic drive to the heart. However, the hypotension is due to an active vascular relaxation rather than withdrawal of sympathetic tone. This relaxation seems partly mediated by an endothelial L-arginine/nitric oxide pathway through peripheral muscarinic receptor activation (endothelium-dependent relaxation) and predominantly through an inhibition of calcium inward current (endothelium-independent relaxation).

Avaliaçäo do potencial contraceptivo de plantas da regiäo amazônica / Evaluation of the contraceptive potencial of plants from the amazon region

Apresentam-se resultados sobre efeito inibidor da fertilidade em ratas, tratadas com plantas usadas por populaçöes da regiäo amazônica. Nos testes inciais com oito plantas, as seguintes revelaram efeito zigotóxico ou de inibiçäo da implantaçäo e desenvolvimento embrionário: Cusparia toxicaria, Petiveria alliacea, Inga edulis e Endopleura uichi