Linalool-rich rosewood essential oil (Aniba rosaeodora Ducke) mitigates emotional and neurochemical impairments induced by ethanol binge-like exposure during adolescence in female rats.

Linalool-rich Rosewood oil (Aniba rosaeodora Ducke) is a natural compound widely used in perfumery industry. Evidence suggests that linalool exerts antidepressant and anxiolytic effects. Conversely, ethanol binge drinking (i.e., intermittent and episodic consumption) during adolescence elicits neurobehavioral alterations associated with brain damage. Here, we investigated whether linalool-rich Rosewood oil administration can improve the emotional and molecular impairments associated with ethanol binge-like exposure during adolescence in female rats. Rosewood oil was obtained by hydrodistillation and posteriorly analyzed. Adolescent female Wistar rats received four-cycles of ethanol binge-like pattern (3 g/kg/day, 3 days on/4 days off) and daily Rosewood oil (35 mg/kg, intranasally) for 28 days. Twenty-four hours after treatments, it was evaluated the impact of ethanol exposure and Rosewood oil treatment on the putative emotional impairments assessed on the splash and forced swimming tests, as well as the levels of brain-derived neurotrophic factor (BDNF), S100B, oxidative parameters, and inflammatory cytokines in prefrontal cortex and hippocampus. Results indicated that Rosewood oil intranasal administration mitigated emotional impairments induced by ethanol exposure accompanied by a marked increase in BDNF, S100B, glutathione (GSH), and antioxidant activity equivalent to Trolox (TEAC) levels in brain areas. Rosewood oil treatment also prevented the ethanol-induced increase of interleukin-1ß, interleukin-6, tumor necrosis factor α (TNF-α), and neurofilament light chain (NFL) levels. These findings provide the first evidence that Rosewood oil intranasal administration exerts protective effects against emotional and molecular impairments associated with adolescent ethanol binge-like exposure, possibly due to linalool actions triggering neurotrophic factors, rebalancing antioxidant status, and attenuating proinflammatory process.

Phenolic Monoterpenes Conversion of Conobea scoparioides Essential Oil by Hydrotalcite Synthesized from Blast-Furnace Slag.

Conobea scoparioides (Plantaginaceae) is an herbaceous plant known as "pataqueira" that grows wild in seasonally wet areas of the Amazon region. It is used for aromatic baths and anti-protozoan remedies by the Brazilian Amazon native people. The main volatile compounds identified in the essential oil of "Pataqueira" were the phenolic monoterpenes thymol and thymol methyl ether and their precursors, the monoterpene hydrocarbons α-phellandrene and p-cymene. A hydrotalcite synthesized from blast-furnace slag exhibited a 3:2 (Mg/Al) molar ratio, and this layered double hydroxide (LDH) was evaluated as a catalyst in converting the main monoterpenes of the "Pataqueira" oil. This action significantly increased the thymol content, from 41% to 95%, associated with the percentual reduction in other main components, such as thymol methyl ether, α-phellandrene, and p-cymene. The LDH reaction showed a strong tendency towards producing hydroxylated derivatives, and its behavior was similar to the hypothetical plant biosynthetic pathway, which leads to the production of the monoterpenes of "Pataqueira" oil. Thymol and its derivatives are potent antiseptics applied in pharmaceutical and hygienic products as antibacterial, antifungal, and antioxidant properties, among others. The present work reports a natural source with a high thymol content in aromatic plants from the Amazon, with evident economic value.

Volatile Constituents from Catasetum (Orchidaceae) Species with Occurrence in the Brazilian Amazon.

BACKGROUND: Catasetum Rich. ex Kunth is a genus of Neotropical orchids distributed in Central and South American regions. In the Brazilian Amazon, there are more than 60 species of Catasetum. The floral aromas of orchids are little known, particularly of Catasetum species. This work aimed to analyze the chemical constituents of the volatile concentrates of eight Catasetum specimens from the Amazon: C. alatum (1), C. albovirens (2), C. barbatum (1), C. ciliatum (2), C. galeritum (1), and C. gnomus (1). METHODS: Gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) analyzed and identified the constituents of the volatile concentrates, and principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used in the multivariate statistical analysis. RESULTS: The Catasetum main constituents in descending order and above 10% were trans-geranylgeraniol, 1,4-dimethoxybenzene, linalool, 2-phenylethyl acetate, geraniol, 7-epi-1,2-dehydro-sesquicineole, 1,8-cineole, benzyl acetate, limonene, methyl salicylate, (E)-ß-farnesene, anisyl butyrate, cis-carvone oxide, cadin-4-en-10-ol, indole, α-pinene, and δ-cadinene. CONCLUSIONS: Multivariate statistical analysis of Catasetum species showed that C. barbatum, C. albovirens, and C. gnomus are distinct from the other studied species, while C. alatum, C. ciliatum, and C. galeritum presented the same primary classes of compounds. These results contribute to a better understanding of the genus Catasetum chemotaxonomy.

Flavonoids, antioxidant potential and antimicrobial activity of Myrcia rufipila mcvaugh leaves (myrtaceae).

This paper reports the first chemical study of the non-volatile compounds, antioxidant capacity and antimicrobial effect of the methanol extract of the leaves of Myrcia rufipila McVaugh. Samples of the leaves were collected in Maracanã Municipality, Pará, Brazil. The chemical investigation led to the identification of the triterpenoids ß- and α-amyrin, the flavonoids 4'-O-galloyldihydromyricetin, myricetin, myricitrin, desmantin-I, myricetin-3-O-(3"-O-galloyl)-α-L-rhamnopyranoside and isovitexin, in addition to gallic acid. The methanol extract showed antioxidant capacity (>90%) against DPPH radical (IC50 356.3 ± 3.1 µg.mL-1) and was active only at high concentrations against the tested microorganisms, including the chloramphenicol resistant E. coli CCMB261 and S. aureus CCMB285 and a nystatin resistant C. parapsilosis CCMB 288. This study shows that M. rufipila, like other Myrcia species, is another source of flavonoids such as desmantin-I and myricitrin which have shown hypoglycemic potential, besides triterpenes and phenolic acids.

Composition and Larvicidal Activity of the Oil of Dizygostemon riparius (Plantaginaceae), a New Aromatic Species Occurring in Maranhão, Brazil.

Dizygostemon riparius (Plantaginaceae) is a new aromatic herbaceous species occurring in Maranhão State, Brazil. It is used as flavorings to remove domestic animal parasites and preventing mosquitoes. GC and GC/MS were used to analyze its essential oil, and a larvicidal bioassay was performed against Aedes albopictus larvae, a vector of arboviruses in Brazil. endo-Fenchyl acetate, endo-fenchol, (E)-caryophyllene, and caryophyllene oxide were the oil's primary constituents, totalizing 88.0 %. The two morphotypes of D. riparius, with purple and white flowers, did not present a significant difference in the oils' composition. From a chemotaxonomic point of view, D. riparius oil showed some similarities with other oils of Plantaginaceae, suggesting (E)-caryophyllene and caryophyllene oxide as possible chemical markers. The oil larvicidal action displayed the lowest and highest mortality percentage at 50 mg/L (2.0 %) and 600 mg/L (88.0 %). The fenchyl acetate and fenchol standards showed a lower and higher mortality percentage at a concentration of 300 mg/L (42.0 % and 26.0 %) and 900 mg/L (96.0 % and 98.0 %), respectively. The present study results with the D. riparius oil point to a new bioproduct with significant larvicidal activity.

Effects of inoculation by arbuscular mycorrhizal fungi on the composition of the essential oil, plant growth, and lipoxygenase activity of Piper aduncum L.

The aim of this study was to evaluate the changes in the production of secondary metabolites Piper aduncum seedlings were inoculated by spores of the arbuscular mycorrhizal fungi (AMF) Rhizophagus clarus and Claroideoglomus etunicatum. P. aduncum seedlings were inoculated by spores of R. clarus and C. etunicatum and then, development parameters, root colonization, lipoxygenase (LOX) activity, and essential oil (OE) chemical composition were monitored at 30, 60 and 90 days' post-inoculation (dpi). The inoculation had influenced the plant height and root length at 30 and 90 dpi and microscopic analysis of roots showed the presence of hyphae, arbuscules and vesicles in the inoculated plants. Phenylpropanoids and sesquiterpene hydrocarbons were the main compounds in the EO. In the leaves, the concentration of phenylpropanoids showed a decrease, mainly at 60 dpi, with increased sesquiterpene hydrocarbon production. The main compounds were dillapiole, myristicin, and germacrene D; the dillapiole concentration decreased in all treatments. LOX activity had an increase in the leaves and roots at 90 dpi. These results suggest that alterations in the secondary metabolites of P. aduncum can be induced by its mechanisms of resistance during AMF interaction.

Lupane triterpenoids, antioxidant potential and antimicrobial activity of Myrciaria floribunda (H. West ex Willd.) O. Berg.

Chemical composition of the methanol extract of Myrciaria floribunda leaves was investigated. The nor-lupane triterpenoids platanic acid and messagenic I acid were identified, along with other known triterpenoids (betulinic aldehyde, ursolic acid acetate and betulinic acid), a new lupane triterpenoid (2α,6α,30-trihydroxybetulinic acid) and the flavonoids catechin, quercetrin and mirycitrin. The structures were determined by spectroscopic methods (NMR, LC-MS, GC-MS). The major isolated compound was betulinic acid. The methanol extract and 2α,6α,30-trihydroxybetulinic acid were evaluated for their DPPH scavenging potential. The tested triterpenoid was one hundred times more active than betulinic acid, but less active than the extract. Screening for antimicrobial activity showed that the methanol extract was active against Staphylococcus aureus and Escherichia coli, but inactive against Candida albicans and Candida krusei, while 2α,6α,30-trihydroxybetulinic acid was inactive to all tested microorganisms.

Planting and seasonal and circadian evaluation of a thymol-type oil from Lippia thymoides Mart. & Schauer.

BACKGROUND: The oil and extracts of Lippia thymoides have been used for various medicinal and food applications. Entrepreneurs in the Amazon have been considering the economic exploitation of this plant. The present study evaluated the influence of the seasonal and circadian rhythm on the yield and composition of the essential oil of leaves and thin branches of a Lippia thymoides specimen cultivated in Abaetetuba, State of Pará, Brazil. The constituents of the oils were identified by GC and GC-MS and with the application of multivariate analysis: Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA). RESULTS: The predominance of oxygenated monoterpenes (70.6-91.8%) was observed in oils, followed by monoterpene hydrocarbons (1.2 to 21.6%) and sesquiterpene hydrocarbons (3.9 to 9.1%). Thymol, thymol acetate, γ-terpinene, p-cymene, and (E)-caryophyllene were the first compounds. The mean thymol content was higher in the rainy season (seasonal: 77.0%; circadian: 74.25%) than in the dry period (seasonal: 69.9%; circadian: 64.5%), and it was influenced by climatic variables: rainfall precipitation, solar radiation, temperature, and relative humidity. For the circadian study, PCA and HCA analysis were applied to the constituents of oils from rainy and dry periods. Two groups were formed. A higher thymol content characterized the group 1, followed by (Z)-hexen-3-ol, α-thujene, α-pinene, α-phellandrene and humulene epoxide II, in minor percent. A higher content of p-cymene formed the group 2, γ-terpinene, thymol acetate and (E)-caryophyllene, followed by myrcene, α-terpinene, 1,8-cineole, terpinen-4-ol, methylthymol, and germacrene D, in a low percentage. CONCLUSIONS: The different chemical profiles found in the oils of L. thymoides must be associated with the environmental conditions existing at its collection site. The knowledge of this variation in the oil composition is essential from the ecological and taxonomic point of view, regarding the management and economic use of the species.

Chemical Composition of Four Essential Oils of Eugenia from the Brazilian Amazon and Their Cytotoxic and Antioxidant Activity.

Background:Eugenia species are appreciated for their edible fruits and are known as having anticonvulsant, antimicrobial and insecticidal actions. Methods: The plant material was collected in the southeastern Pará state of Brazil and submitted to hydrodistillation. GC-MS analyzed the oils, and their antioxidant and cytotoxic activities were evaluated by the DPPH and MTT assays. Results: The main components identified in the Eugenia oils were 5-hydroxy-cis-calemene, (2E,6E)-farnesol, (2E,6Z)-farnesol, caryophylla-4(12),8(13)-dien-5α-ol-5ß-ol, E-γ-bisabolene, ß-bisabolene, germacrene D, and ishwarane. The oil of E. egensis showed the most significant antioxidant activity (216.5 ± 11.6 mg TE/mL), followed by the oils of E. flavescens (122.6 ± 6.8 mg TE/mL) and E. patrisii (111.2 ± 12.4 mg TE/mL). Eugenia oils were cytotoxic to HCT-116 (colon cancer) cells by the MTT assay, where the most active was the oil of E. polystachya (10.3 µg/mL), followed by the oils of E. flavescens (13.9 µg/mL) and E. patrisii (16.4 µg/mL). The oils of E. flavescens and E. patrisii showed the highest toxicity for MRC5 (human fibroblast) cells, with values of 14.0 µg/mL and 18.1 µg/mL, respectively. Conclusions: These results suggest that Eugenia oils could be tested in future studies for the treatment of colon cancer and oxidative stress management.

Tyrosinase inhibitory activity, molecular docking studies and antioxidant potential of chemotypes of Lippia origanoides (Verbenaceae) essential oils.

The essential oils (EOs) of the aerial parts of Lippia origanoides (LiOr), collected in different localities of the Amazon region, were obtained by hydrodistillation and analyzed by GC and CG-MS. Principle component analysis (PCA) based on chemical composition grouped the oils in four chemotypes rich in mono- and sesquiterpenoids. Group I was characterized by 1,8-cineole and α-terpineol (LiOr-1 and LiOr-4) and group II by thymol (LiOr-2). The oil LiOr-3 showed ß-caryophyllene, α-phellandrene and ß-phellandrene as predominant and LiOr-5 was rich in (E)-nerolidol and ß-caryophyllene. All samples were evaluated for antioxidant activity and inhibition of tyrosinase in vitro and in silico. The highest antioxidant activity by the DPPH free radical method was observed in LiOr-2 and LiOr-5 oils (132.1 and 82.7 mg TE∙mL-1, respectively). The tyrosinase inhibition potential was performed using L-tyrosine and L-DOPA as substrates and all samples were more effective in the first step of oxidation. The inhibition by samples LiOr-2 and LiOr-4 were 84.7% and 62.6%, respectively. The samples LiOr-1, LiOr-4 and LiOr-5 displayed an interaction with copper (II) ion with bathochromic shift around 15 nm. In order to elucidate the mechanism of inhibition of the main compounds, a molecular docking study was carried out. All compounds displayed an interaction between an oxygen and Cu or histidine residues with distances less than 4 Å. The best docking energies were observed with thymol and (E)-nerolidol (-79.8 kcal.mol-1), which suggested H-bonding interactions with Met281 and His263 (thymol) and His259, His263 ((E)-nerolidol).

Chemical Profile and in vitro Biological Activities of Essential Oils of Nectandra puberula and N. cuspidata from the Amazon.

Essential oils (EO) from leaves and branches of Nectandra puberda Schott (Nees) and from leaves of N. cuspidata Nees & Mart. were obtained by hydrodistillation and their chemical compositions determined by gas chromatography - mass spectrometry (GC-MS). The main compounds identified from N. puberula EO were apiole (22.2%), ß-caryophyllene (15.1%), ß-pinene (13.3%), germacrene D (8.3%), pogostol (6.6%) and bicyclogermacrene (6.4%) in the leaves; and apiole (28.1%), pogostol (19.8%) and guaiol (11.2%) in the branches. The EQ of N. cuspidata leaves showed ß-caryophyllene (26.9%), bicyclogermacrene (16.0%) and spathulenol (5.2%) as the main compounds. The EOs were subjected to antibacterial screening and displayed promising activity against Escherichia coli (MIC = 19.5 µg.mL⁻¹). In addition, the EOs were tested for cytotoxic activity against MCF-7 breast tumor cells and the IC50 values were 64.5 ± 1.6 and 117.1 ± 11.9 µg.mL⁻¹ for the leaf EOs of N. puberula and N. cuspidata, respectively.

Composition and cytotoxic and antioxidant activities of the oil of Piper aequale Vahl.

BACKGROUND: Piper aequale Vahl is a small shrub that grows in the shadow of large trees in the Carajás National Forest, Municipality of Parauapebas, Para state, Brazil. The local people have used the plant against rheumatism and inflammation. METHODS: The essential oil of the aerial parts was extracted and analyzed by GC and GC-MS. The MTT colorimetric assay was used to measuring the cytotoxic activity of the oil against human cancer lines. The determination of antioxidant activity of the oil was conducted by DPPH radical scavenging assay. RESULTS: The main constituents were δ-elemene (18.92 %), ß-pinene (15.56 %), α-pinene (12.57 %), cubebol (7.20 %), ß-atlantol (5.87 %), and bicyclogermacrene (5.51 %), totalizing 65.63 % of the oil. The oil displayed a strong in vitro cytotoxic activity against the human cancer cell lines HCT-116 (colon) and ACP03 (gastric) with IC50values of 8.69 µg/ml and 1.54 µg/ml, respectively. The oil has induced the apoptosis in a gastric cancer cells in all tested concentration (0.75-3.0 µg/ml), after 72 h of treatment, when compared to negative control (p < 0.001). Also, the oil showed a significant antioxidant activity (280.9 ± 22.2 mg TE/ml), when analyzed as Trolox equivalent, and a weak acetylcholinesterase inhibition, with a detection limit of 100 ng, when compared to the physostigmine standard (1.0 ng). CONCLUSION: The higher cell growth inhibition induced by the oil of P. aequale is probably due to its primary terpene compounds, which were previously reported in the proliferation inhibition, in stimulation of apoptosis and induction of cell cycle arrest in malignant cells.

Phenylpropanoid-rich Essential Oils of Piper Species from the Amazon and their Antifungal and Anti-cholinesterase Activities.

The essential oils (EOs) from aerial parts of Piper aduncum, P. callosuin and P. marginatum, collected from the Amazon region of Brazil, were analyzed by GC-MS and then evaluated for their antifungal and anticholinesterase activities. The essential oils were dominated by phenylpropanoids, such as dillapiole (73.0%) in P. aduncum, safrole (66.0%) in P. callosum and 3,4-methylenedioxypropiophenone (21.8%) in P. inarginatum. The analyzed oils showed low to moderate antifungal activity; with detection limits (DL) from 10 to 100 pg against Cladosporium cladosporioides and C. sphareospermum. In the anticholinesterase (AChE) evaluation, the oils of P. callosum (DL = 0.01 ng) and P. marginatum (DL = 0.01 ng) were one hundred times more potent than the standard physostigmine (DL = 1.0 ng). Molecular docking analysis showed that phenylpropanoids docked reasonably well with acetyleholinesterase and may be responsible for the anti-AChE activities of the Piper EOs. This is the first presentation about acetylcholinesterase inhibition by methylenedioxyphenyl-propanoids.

Essential oils composition of croton species from the Amazon.

The essential oils of leaves and twigs from the Euphorbiaceous Croton draconoides, C. urucurana and Julocroton triqueter were obtained and analyzed by GC and GC-MS. In total, 101 volatile constituents were identified, comprising an average of 90% of the oil, mostly made up of mono- and sesquiterpenes. The monoterpene hydrocarbons varied from 1.2 to 40.2%, the sesquiterpene hydrocarbons from 34.0 to 49.6% and the oxygenated sesquiterpenes from 11.5 to 51.3%. The main compounds found in the oil of C. draconoides were beta-pinene (16.9%), alpha-pinene (16.5%), curzerene (12.8%), germacrene D (9.0%), gamma-elemene (4.7%), and elemol (4.4%). The oil of C. urucurana showed sesquicineole (23.0%), dehydro-sesquicineole (13.8%), beta-caryophyllene (7.9%), beta-bisabolol (5.0%), germacrene D (4.2%) and beta-elemene (4.1%) as the chief compounds. The oil of J. triqueter was dominated by beta-caryophyllene (16.3%), beta-phellandrene (10.2%), spathulenol (5.1%), caryophyllene oxide (5.0%), delta-cadinene (4.3%), (E)-nerolidol (4.3%), and alpha-copaene (4.1%).

Molluscicidal and larvicidal activities and essential oil composition of Cymbopogon winterianus.

UNLABELLED: CONTEXT. Cymbopogon winterianus Jowitt ex Bor (Poaceae), known as citronella grass, is an aromatic herbaceous plant and the essential oil extracted from this grass is used in cosmetics, perfumes, hygiene and cleanliness products worldwide. OBJECTIVE: This study investigated the composition and molluscicidal and larvicidal activities of the essential oil of C. winterianus cultivated in North Brazil. MATERIALS AND METHODS: The oil was obtained by hydrodistillation, analyzed by gas chromatography (GC) and GC-mass spectrometry and then its molluscicidal and larvicidal activities against snails (Biomphalaria glabrata) and hatched larvae of Artemia salina, respectively, were evaluated at concentrations from 10 to 1000 mg/L. RESULTS: The main constituents of oil were citronellal (26.5%), geraniol (16.2%), elemol (14.5%) and citronellol (7.3%). The molluscicidal test revealed significant lethal concentration (LC) values (LC90=97.0 mg/L, LC50=54.0 mg/L and LC20=22.0 mg/L), indicating the presence of molluscicidal compounds in the oil. In addition, the oil showed moderate larvicidal activity (LC50=181.0 mg/L) against the larvae of A. salina, which could justify its use in the aquatic environment without affecting other living organisms. DISCUSSION AND CONCLUSION: The results suggest that the oil of C. winterianus could be an effective alternative to control schistosomiasis, with an average margin of safety to other living organisms that coexist with snails.

Antioxidant capacity and larvicidal and antifungal activities of essential oils and extracts from Piper krukoffii.

The leaves and twigs of Piper krukoffii, collected in the Carajás National Forest, north Brazil, yielded essential oils (2.0% and 0.8%), the main constituents of which were myristicin (40.3% and 26.7%), apiole (25.4% and 34.1%) and elemicin (2.8% and 3.0%). The antioxidant activities of the oils, methanol extract and its sub-fractions were evaluated. The DPPH EC50 values varied from the ethyl acetate sub-fraction (73.4 +/- 3.7 microg/mL) to the methanol extract (24.9 +/- 0.8 microg/mL), and the ABTS TEAC values ranged in the same order from 265.7 to 349.2 microMol TE/g. These results indicated a significant antioxidant activity for the plant. The lignans (-)-kusunokin, yatein, (-)-hinokin and cubebin were identified in the methanol extract. The hydro-methanolic sub-fraction showed a high value for total phenol content (106.5 +/- 0.7 mg GAE/g), as well as 1H NMR signals for sugar moieties. Crude extracts and sub-fractions were also able to inhibit beta-carotene bleaching, varying from 22.4 to 47.1%. The oils from the leaves and twigs showed strong larvicidal (21.4 and 3.6 microg/mL) and fungicide (0.5 and 0.1 microg/mL) activities.

Antioxidant capacity and larvicidal activity of essential oil and extracts from Lippia grandis

The leaves and thin branches of Lippia grandis Schauer, Verbenaceae, are used for flavoring of food in the Brazilian Amazon, as substitute for oregano. In this study the constituents of the essential oil were identified and the antioxidant capacity and larvicidal activity of the oil and methanol extract and its sub-fractions were evaluated. A sensory evaluation was determined in view of absence of toxicity. The oil showed a yield of 2.1 percent and its main constituents were thymol (45.8 percent), p-cymene (14.3 percent), γ-terpinene (10.5 percent), carvacrol (9.9 percent) and thymol methyl ether (4.8 percent), totalizing 85 percent. The DPPH radical scavenging activity showed values for the EC50 between 9.0 and 130.5 µg mL-1 and the TEAC/ABTS values varied from 131.1 to 336.0 mg TE/g, indicating significant antioxidant activity for the plant. The total phenolic content ranged from 223.0 to 761.4 mg GAE/g, contributing to the antioxidant activity observed. The crude extracts inhibited the bleaching of β-carotene and the oil showed the greatest inhibition (42.5 percent). The oil (LgO, 7.6±2.4 µg mL-1) showed strong larvicidal activity against the brine shrimp bioassay. The sensory evaluation was highly satisfactory in comparison to oregano. The results are very promising for the use of L. grandis in seasoning and antioxidant products.

Essential oil composition, antioxidant capacity and antifungal activity of Piper divaricatum.

The major components of the essential oil of Piper divaricatum from Marajó Island, PA, Brazil, were methyleugenol (63.8%) and eugenol (23.6%), which were identified by GC and GC-MS. Essential oils of Piper species from the Brazilian Amazon are rich in either mono- and sesquiterpenes or phenylpropanoids, as seen in this study. The oil was able to scavenging the DPPH radical, displaying an inhibition varying from 19% to 74%, with an EC50 value of 16.2 +/- 1.9 microg mL(-1). In the bleaching of beta-carotene, the inhibition of the oil oxidation was 60.0 +/- 2.7%. The oil gave minimum inhibitory concentrations for the fungi Cladosporium cladosporioides and C. sphareospermum of 0.5 microg and 5.0 microg, respectively. The oil also showed significant brine shrimp larvicidal activity (LC50, 38.8 +/- 0.8 microg mL(-1)).

Essential oil composition and antioxidant capacity of Lippia schomburgkiana.

The leaves and fine stems of Lippia schomburgkiana recorded an essential yield of 1.8%, the main constituents of which were 1,8-cineole (64.1%) and alpha-terpineol (12.0%). The methanol extract of L. schomburgkiana inhibited the DPPH radical, resulting in an EC50 value of 16.1 +/- 0.7 microg x mL(-1), which is only three times lower than that of trolox (4.7 +/- 0.4 microg x mL(-1)), signifying a high antioxidant activity for the species. The amount of total phenolics (376.7 +/- 35.5 mg GAE/g) and the trolox equivalent antioxidant capacity (327.0 +/- 24.8 mg TE/g) of the methanol extract confirmed the significant antioxidative capacity of this plant. The brine shrimp bioassay carried out on the oil (49.6 +/- 0.4 microg x mL(-1)) showed high toxicity, providing important evidence of its biological activity. The sensory evaluation of the leaves of L. schomburgkiana showed a percentage acceptance value very close to commercial oregano, indicating that the plant can be used in spice and condiment products.

Essential oil composition of three Peperomia species from the Amazon, Brazil.

The essential oils of three species of Peperomia from the Amazon, Brazil, were hydrodistilled and their 96 volatile constituents identified by GC and GC-MS. The main constituents found in the oil of P. macrostachya were epi-alpha-bisabolol (15.9%), caryophyllene oxide (12.9%), myristicin (7.6%), an aromatic compound (6.6%) and limonene (5.4%). The oil of P. pellucida was dominated by dillapiole (55.3%), (E)-caryophyllene (14.3%) and carotol (8.1%). The major volatile found in the oil of P. rotundifolia was decanal (43.3%), probably a fatty acid-derived compound, followed by dihydro-P3-santalol (9.0%), (E)-nerolidol (7.9%) and limonene (7.7%). The aromatic compounds elemicin, myristicin, apiole, dillapiole and safrole identified in these Peperomia species has been found also in Amazon Piper species. The oils and methanol extracts showed high brine shrimp larvicidal activities. The oil of P. rotundifolia (LC50 = 1.9 +/- 0.1 microg/mL) was the more toxic, followed by the extract of P. pellucida (LC50 = 2.4 +/- 0.5 microg/mL) and the oil of P. macrostachya (LC50 = 9.0 +/- 0.4 microg/mL), therefore with important biological properties.