Antifungal chemosensitization through induction of oxidative stress: A model for control of candidiasis based on the Lippia origanoides essential oil.

In this work, evaluated the antifungal chemosensitizing effect of the Lippia origanoides essential oil (EO) through the induction of oxidative stress. The EO was obtained by hydrodistillation and analyzed by GC-MS. To evaluate the antifungal chemosensitizing effect through induction of oxidative stress, cultures of the model yeast Saccharomyces cerevisiae ∆ycf1 were exposed to sub-inhibitory concentrations of the EO, and the expression of genes known, due be overexpressed in response to oxidative and mutagenic stress was analyzed by quantitative real-time polymerase chain reaction (qRT-PCR) method. Carvacrol and thymol were identified as the main components. The EO was effective in preventing or reducing the growth of the microorganisms tested. The gene expression profiles showed that EO promoted changes in the patterns of expression of genes involved in oxidative and mutagenic stress resistance. The combined use of the L. origanoides EO with fluconazole has been tested on Candida yeasts and the strategy resulted in a synergistic enhancement of the antifungal action of the azolic chemical product. Indeed, in association with EO, the fluconazole MICs dropped. Thus, the combinatorial use of L. origanoides EO as a chemosensitizer agent should contribute to enhancing the efficiency of conventional antifungal drugs, reducing their negative side effects.

Volatile Profiles and DNA Barcodes of Myrtaceae Species with Occurrence in the Brazilian Amazon.

Myrtaceae family includes many species with taxonomic challenges, making it one of the most complex families to identify. This study used DNA barcoding to find molecular markers for species authentication based on the Myrtaceae family's chemical composition and genetic diversity. Essential oils and genetic material were extracted from the leaves of six different species: Eugenia uniflora, E. patrisii, Myrcia splendens, Psidium guajava, P. guineense, and Psidium sp. The samples were analyzed based on compound classes and grouped into two categories. Group I included samples with high amounts of oxygenated sesquiterpenes (3.69-76.05 %) and fatty acid derivatives (0.04-43.59 %), such as E. uniflora, Myrcia splendens, and E. patrisii. Group II included samples P. guajava, P. guineense, and Psidium sp., which had a significant content of monoterpene hydrocarbons (0.69-72.35 %), oxygenated sesquiterpenes (8.06-68.1 %), phenylpropanoids (0.45-22.59 %), and sesquiterpene hydrocarbons (0.27-21.84 %). The PsbA-trnH gene sequences had a high genetic variability, allowing the species to be distinguished. A phylogenetic analysis showed two main clusters with high Bootstrap values corresponding to the subtribes Eugeniineae, Myrciinae, and Pimentinae. The results suggest a weak correlation between genetic and chemical data in these Myrtaceae species.

Seasonal and Circadian Evaluation of the Essential Oil of Dizygostemon riparius (Plantaginaceae), a Wild Flavoring Herb from East Maranhão, Brazil.

Dizygostemon riparius (Plantaginaceae) is an aromatic herbal species known as "Melosa", endemic to the Municipality of São Benedito do Rio Preto, East Maranhão state, Brazil. It has a refreshing and pleasant aroma and is used for food flavoring and controlling domestic animal parasites. This work aimed to evaluate the seasonal and circadian influence on the composition and production of essential oils (EOs) from D. riparius. The plant aerial parts were hydrodistilled, and the oils were analyzed by GC and GC/MS. The seasonal study was conducted from August 2019 to July 2020, and the circadian study in dry (November) and rainy (May) periods, at 6 am, 12 am, and 6 pm. The results showed that the medium EOs yield was 2.8 %, and the primary constituents (>2 %) were endo-fenchyl acetate (30.5-42.1 %) and endo-fenchol (31.6-37.4 %), (E)-caryophyllene (2.8-7.6 %), α-fenchene (3.3-6.5 %), p-cymene (0.7-4.5 %), and caryophyllene oxide (1.4-2.7 %). Yield and composition of EOs did not significantly correlate with the climatic parameters, but their seasonal percentages influenced their two main components due to precipitation and solar radiation environmental factors. Quantitative variability in the EOs composition during the dry and rainy seasons was observed in the circadian period. These data may be significant for the plant's economic use.

Chemometrics of the Composition and Antioxidant Capacity of Hyptis crenata Essential Oils from Brazil.

Hyptis crenata (Pohl) ex Benth is used in traditional medicine as an analgesic to treat general pain. Six Hyptis crenata samples (Hc-1 to Hc-6) were collected in Pará state, Brazil. The leaf essential oils were obtained by hydrodistillation, and GC-MS and GC-FID were used to analyze their chemical compositions. The antioxidant capacity was measured in vitro using DPPH and carotene/linoleic acid assays. Chemometrics analysis (PCA, HCA, and clustered heat map) were used to identify the sample relationships between those collected in this study and those from the literature (Hc-7 to Hc-16) samples. According to the main chemical constituents identified in the samples described in this work and the literature, the sixteen samples were classified into ten groups. Group I was characterized by 1,8-cineole (31.0%), α-pinene (13.6%), (E)-caryophyllene (7.8%), and ß-pinene (7.6%); and Group IV was characterized by 1,8-cineole (17.4-23.5%), α-pinene (15.7-23.5%), ß-pinene (10.5-13.4%), and limonene (8.5-9.7%). Both groups are described for the first time. The total antioxidant capacity was expressed in Trolox Equivalent Antioxidant Capacity values (TEAC): TEAC of Hc-5 (551.9 mg.TE/g) and Hc-6 (475.1 mg.TE/g). In the ß-carotene/linoleic acid assay, the highest inhibition was from Hc-2 (40.0%), Hc-6 (39.0%), and Hc-3 (29.4%).

Stability and Antioxidant Activity of Pouteria macrophylla Fruit Extract, a Natural Source of Gallic Acid.

Pouteria macrophylla (cutite) fruits are rich in phenolic acids, resulting in antioxidant and skin depigmenting activity. The aim of this study, then, is to evaluate the cutite extract stability under three variations of light, time, and temperature using a Box-Behnken experimental design to analyze through the surface response the variations of the total phenolic content (TPC), antioxidant activity (AA), and gallic acid content (GA). A colorimetric assay was also performed, and a decrease in the darkening index was noticed due to the high phenolic coloration in the presence of light, indicating less degradation to extract stability. The experimental planning showed variations in all responses, and second-order polynomial models were calculated and considered predictable, as well as the effects were significant. The TPC exhibited a variation in less concentrated samples (0.5% p/v) at higher temperatures (90 °C). In contrast, the temperature was the only influential variable for AA, where only higher temperatures (60-90 °C) were able to destabilize the fruit extract. Differently, GA showed only the concentration as the influential variable, exhibiting that neither temperature nor time of exposure could affect the gallic acid content stability of P. macrophylla extract. For this, P. macrophylla extract was shown to be highly stable, providing a great perspective on cosmetic application.

Seasonal Variation in Essential Oil Composition and Antioxidant Capacity of Aniba canelilla (Lauraceae): A Reliable Source of 1-Nitro-2-phenylethane.

Aniba canelilla (Kunth) Mez essential oil has many biological activities due to its main compound 1-nitro-2-phenylethane (1N2F), followed by methyleugenol, a carcinogenic agent. This study analyzed the influence of seasonality on yields, antioxidant capacity, and 1N2F content of A. canelilla leaf and twig essential oils. Essential oils (EOs) were extracted with hydrodistillation and analyzed with gas chromatography coupled to mass spectrometry and a flame ionization detector. Antioxidant capacity was measured using the free radical scavenging method (DPPH). Chemometric analyses were carried out to verify the influence of climatic factors on the production and composition of EOs. 1-Nitro-2-phenylethane was the major constituent in A. canelilla EOs throughout the seasonal period (68.0-89.9%); methyleugenol was not detected. Essential oil yields and the 1N2F average did not show a statistically significant difference between the dry and rainy seasons in leaves and twigs. Moderate and significant correlations between major compounds and climate factor were observed. The twig oils (36.0 ± 5.9%) a showed greater antioxidant capacity than the leaf oils (20.4 ± 5.0%). The PCA and HCA analyses showed no statistical differences between the oil samples from the dry and rainy seasons. The absence of methyleugenolin in all months of study, described for the first time, makes this specimen a reliable source of 1N2F.

The Volatile Profiles and DNA Barcodes of Lauraceae Species from the Ocotea Complex with Occurrence in the Brazilian Amazon.

The Ocotea complex accommodates most of the taxonomic diversity of Neotropical Lauraceae with economic importance and biological potential attributed to their essential oils (EOs) and extracts. However, the botanical taxonomy has had limitations due to the difficulty of identifying and delimiting species and genera. The chemical and molecular markers of Ocotea complex species in Pará state, Brazil, were assessed according to their EO compositions and DNA sequences of matK, trnL-trnF, and ITS regions. The multivariate analysis of EOs constituents has classified them into two main clusters characterized by oils rich in (I) terpenoids and phenylpropanoids and (II) sesquiterpenes. We conducted a phylogenetic analysis of species based on DNA barcode sequences on the Bayesian Inference (PP: 0.70-1,0) and Maximum Likelihood (BS: 72-100 %). The comparison between the volatile profiles and phylogenetic data indicates two main groups for these species collected from the Ocotea complex.

Variability in the Chemical Composition of Myrcia sylvatica (G. Mey) DC. Essential Oils Growing in the Brazilian Amazon.

Myrcia sylvatica (G. Mey) DC. is known as "insulin plant" because local communities use the infusions of various organs empirically to treat diabetes. The leaves of seven specimens of Myrcia sylvatica (Msy-01 to Msy-07) were collected in the Brazilian Amazon. Furthermore, the essential oils were extracted by hydrodistillation and analyzed by gas chromatography coupled to mass spectrometry, and their chemical compositions were submitted to multivariate analysis (Principal Component Analysis and Hierarchical Cluster Analysis). The multivariate analysis displayed the formation of four chemical profiles (chemotypes), described for the first time as follows: chemotype I (specimen Msy-01) was characterized by germacrene B (24.5%), γ-elemene (12.5%), and ß-caryophyllene (10.0%); chemotype II (specimens Msy-03, -06 and -07) by spathulenol (11.1-16.0%), germacrene B (7.8-20.7%), and γ-elemene (2.9-7.6%); chemotype III (Msy-04 and -05) by spathulenol (9.8-10.1%), ß-caryophyllene (2.5-10.1%), and δ-cadinene (4.8-5.6%); and chemotype IV, (Msy-02) by spathulenol (13.4%), caryophyllene oxide (15.0%), and α-cadinol (8.9%). There is a chemical variability in the essential oils of Myrcia sylvatica occurring in the Amazon region.

Seasonal Variability of a Caryophyllane Chemotype Essential Oil of Eugenia patrisii Vahl Occurring in the Brazilian Amazon.

Eugenia patrisii Vahl is a native and non-endemic myrtaceous species of the Brazilian Amazon. Due to few botanical and phytochemical reports of this species, the objective of the present work was to evaluate the seasonal variability of their leaf essential oils, performed by GC and GC-MS and chemometric analysis. The results indicated that the variation in oil yields (0.7 ± 0.1%) could be correlated with climatic conditions and rainy (R) and dry seasons (D). (E)-caryophyllene (R = 17.1% ± 16.0, D = 20.2% ± 17.7) and caryophyllene oxide (R = 30.1% ± 18.4, D = 14.1% ± 19.3) are the major constituents and did not display significant differences between the two seasons. However, statistically, a potential correlation between the main constituents of E. patrisii essential oil and the climatic parameters is possible. It was observed that the higher temperature and insolation rates and the lower humidity rate, which are characteristics of the dry season, lead to an increase in the (E)-caryophyllene contents, while lower temperature and insolation and higher humidity, which occur in the rainy season, lead to an increase in the caryophyllene oxide content. The knowledge of variations in the E. patrisii essential oil composition could help choose the best plant chemical profile for medicinal purposes.

Chemical Composition and Variability of the Volatile Components of Myrciaria Species Growing in the Amazon Region.

Myrciaria (Myrtaceae) species have been well investigated due to their chemical and biological relevance. The present work aimed to carry out the chemotaxonomic study of essential oils of the species M. dubia, M. floribunda, and M. tenella, sampled in the Brazilian Amazon and compare them with the volatile compositions from other Myrciaria species reported to Brazil and Colombia. The leaves of six Myrciaria specimens were collected (PA, Brazil) during the dry season, and their chemical compositions were analyzed by gas chromatography-mass spectrometer (GC-MS) and gas chromatography-flame ionization detector (GC-FID). The main compounds identified in the essential oils were monoterpenes with pinane and menthane skeletons, followed by sesquiterpenes with caryophyllane and cadinane skeletons. Among the sampled Myrciaria specimens, five chemical profiles were reported for the first time: profile I (M. dubia, α-pinene, 54.0-67.2%); profile II (M. floribunda, terpinolene 23.1%, α-phellandrene 17.7%, and γ-terpinene 8.7%); profile III (M. floribunda, γ-cadinene 17.5%, and an unidentified oxygenated sesquiterpene 15.0%); profile IV (M. tenella, E-caryophyllene 43.2%, and α-humulene 5.3%); and profile V (M. tenella, E-caryophyllene 19.1%, and caryophyllene oxide 41.1%). The Myrciaria chemical profiles showed significant variability in extraction methods, collection sites, plant parts, and genetic aspects.

Essential Oil Chemotypes and Genetic Variability of Cinnamomum verum Leaf Samples Commercialized and Cultivated in the Amazon.

Cinnamomum verum (Lauraceae), also known as "true cinnamon" or "Ceylon cinnamon" has been widely used in traditional folk medicine and cuisine for a long time. The systematics of C. verum presents some difficulties due to genetic variation and morphological similarity between other Cinnamomum species. The present work aimed to find chemical and molecular markers of C. verum samples from the Amazon region of Brazil. The leaf EOs and the genetic material (DNA) were extracted from samples cultivated and commercial samples. The chemical composition of the essential oils from samples of C. verum cultivated (Cve1-Cve5) and commercial (Cve6-c-Cv9-c) was grouped by multivariate statistical analysis of Principal Component Analysis (PCA). The major compounds were rich in benzenoids and phenylpropanoids, such as eugenol (0.7-91.0%), benzyl benzoate (0.28-76.51%), (E)-cinnamyl acetate (0.36-32.1%), and (E)-cinnamaldehyde (1.0-19.73%). DNA barcodes were developed for phylogenetic analysis using the chloroplastic regions of the matK and rbcL genes, and psbA-trnH intergenic spacer. The psbA-trnH sequences provided greater diversity of nucleotides, and matK confirmed the identity of C. verum. The combination of DNA barcode and volatile profile was found to be an important tool for the discrimination of C. verum varieties and to examine the authenticity of industrial sources.

Secondary Metabolic Profile as a Tool for Distinction and Characterization of Cultivars of Black Pepper (Piper nigrum L.) Cultivated in Pará State, Brazil.

This study evaluated the chemical compositions of the leaves and fruits of eight black pepper cultivars cultivated in Pará State (Amazon, Brazil). Hydrodistillation and gas chromatography-mass spectrometry were employed to extract and analyze the volatile compounds, respectively. Sesquiterpene hydrocarbons were predominant (58.5-90.9%) in the cultivars "Cingapura", "Equador", "Guajarina", "Iaçará", and "Kottanadan", and "Bragantina", "Clonada", and "Uthirankota" displayed oxygenated sesquiterpenoids (50.6-75.0%). The multivariate statistical analysis applied using volatile composition grouped the samples into four groups: γ-Elemene, curzerene, and δ-elemene ("Equador"/"Guajarina", I); δ-elemene ("Iaçará"/"Kottanadan"/"Cingapura", II); elemol ("Clonada"/"Uthirankota", III) and α-muurolol, bicyclogermacrene, and cubebol ("Bragantina", IV). The major compounds in all fruit samples were monoterpene hydrocarbons such as α-pinene, ß-pinene, and limonene. Among the cultivar leaves, phenolics content (44.75-140.53 mg GAE·g-1 FW), the enzymatic activity of phenylalanine-ammonia lyase (20.19-57.22 µU·mL-1), and carotenoids (0.21-2.31 µg·mL-1) displayed significant variations. Due to black pepper's susceptibility to Fusarium infection, a molecular docking analysis was carried out on Fusarium protein targets using each cultivar's volatile components. F. oxysporum endoglucanase was identified as the preferential protein target of the compounds. These results can be used to identify chemical markers related to the susceptibility degree of black pepper cultivars to plant diseases prevalent in Pará State.

Essential Oil Composition and DNA Barcode and Identification of Aniba species (Lauraceae) Growing in the Amazon Region.

Lauraceae species are widely represented in the Amazon, presenting a significant essential oil yield, large chemical variability, various biological applications, and high economic potential. Its taxonomic classification is difficult due to the accentuated morphological uniformity, even among taxa from a different genus. For this reason, the present work aimed to find chemical and molecular markers to discriminate Aniba species collected in the Pará State (Brazil). The chemical composition of the essential oils from Aniba canelilla, A. parviflora, A. rosaeodora, and A. terminalis were grouped by multivariate statistical analysis. The major compounds were rich in benzenoids and terpenoids such as 1-nitro-2-phenylethane (88.34-70.85%), linalool (15.2-75.3%), α-phellandrene (36.0-51.8%), and ß-phellandrene (11.6-25.6%). DNA barcodes were developed using the internal transcribed spacer (ITS) nuclear region, and the matK, psbA-trnH, rbcL, and ycf1 plastid regions. The markers psbA-trnH and ITS showed the best discrimination for the species, and the phylogenic analysis in the three- (rbcL + matK + trnH - psbA and rbcL + matK + ITS) and four-locus (rbcL + matK + trnH - psbA + ITS) combination formed clades with groups strongly supported by the Bayesian inference (BI) (PP:1.00) and maximum likelihood (ML) (BS ≥ 97%). Therefore, based on statistical multivariate and phylogenetic analysis, the results showed a significant correlation between volatile chemical classes and genetic characteristics of Aniba species.

Monoterpenes and Sesquiterpenes of Essential Oils from Psidium Species and Their Biological Properties.

Psidium (Myrtaceae) comprises approximately 266 species, distributed in tropical and subtropical regions of the world. Psidium taxa have great ecological, economic, and medicinal relevance due to their essential oils' chemical diversity and biological potential. This review reports 18 Psidium species growing around the world and the chemical and biological properties of their essential oils. Chemically, 110 oil records are reported with significant variability of volatile constituents, according to their seasonality and collection sites. Monoterpenes and sesquiterpenes with acyclic (C10 and C15), p-menthane, pinane, bisabolane, germacrane, caryophyllane, cadinane, and aromadendrane skeleton-types, were the primary constituents. The essential oils showed various biological activities, including antioxidant, antifungal, antibacterial, phytotoxic, larvicidal, anti-inflammatory, and cytotoxic properties. This review contributes to the Psidium species rational and economic exploration as natural sources to produce new drugs.

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.

Chemical composition and biological activities of two chemotype-oils from Cinnamomum verum J. Presl growing in North Brazil.

Chemical composition and antioxidant and antifungal action of the oils from leaves and wood bark of two chemotypes of Cinnamomum verum J. Presl were evaluated. Plants were sampled in the cities of São Luís and Santa Inês, state of Maranhão, Brazil. GC-MS and GC-FID, DPPH radical scavenging, and in vitro test against the phytopathogenic fungus Colletotrichum musae were used to perform these analyses. Cinnamomum verum is worldwide known as Cinnamon, highlighted for its extensive use in the cooking of diverse cultures of the world, and as a medicinal plant to treat environmental viral diseases. In the leaf oil of São Luís chemotype, eugenol (93.6%) was the main constituent, while in Santa Inês chemotype, it was benzyl benzoate (95.3%). In the bark wood oil of São Luís chemotype, (E)-cinnamaldehyde (89.3%) was the main constituent, while in Santa Inês chemotype, they were benzyl benzoate (23.3%), linalool (14.0%), (E)-caryophyllene (9.1%), caryolan-8-ol (7.2%) and borneol (4.7%). Leaf oils from both chemotypes showed strong to moderate antifungal activity, reaching 100% efficacy in eugenol-containing oils and above 70% in benzyl benzoate oils. In the antioxidant evaluation, the chemotype with a high eugenol content presented an inhibitory concentration higher than 80%, compared to Trolox. The leaf oils of the two C. verum chemotypes showed significant antifungal and antioxidant potential, considering their economic use as a functional and nutraceutical food supplement.

Chemical Diversity, Biological Activity, and Genetic Aspects of Three Ocotea Species from the Amazon.

Ocotea species present economic importance and biological activities attributed to their essential oils (EOs) and extracts. For this reason, various strategies have been developed for their conservation. The chemical compositions of the essential oils and matK DNA sequences of O. caudata, O. cujumary, and O. caniculata were subjected to comparison with data from O. floribunda, O. veraguensis, and O. whitei, previously reported. The multivariate analysis of chemical composition classified the EOs into two main clusters. Group I was characterized by the presence of α-pinene (9.8-22.5%) and ß-pinene (9.7-21.3%) and it includes O. caudata, O. whitei, and O. floribunda. In group II, the oils of O. cujumary and O. caniculata showed high similarity due amounts of ß-caryophyllene (22.2% and 18.9%, respectively). The EO of O. veraguensis, rich in p-cymene (19.8%), showed minor similarity among all samples. The oils displayed promising antimicrobial and cytotoxic activities against Escherichia coli (minimum inhibitory concentration (MIC) < 19.5 µg·mL-1) and MCF-7 cells (median inhibitory concentration (IC50) ≅ 65.0 µg·mL-1), respectively. The analysis of matK gene displayed a good correlation with the main class of chemical compounds present in the EOs. However, the matK gene data did not show correlation with specific compounds.

Essential Oils from Neotropical Piper Species and Their Biological Activities.

The Piper genus is the most representative of the Piperaceae reaching around 2000 species distributed in the pantropical region. In the Neotropics, its species are represented by herbs, shrubs, and lianas, which are used in traditional medicine to prepare teas and infusions. Its essential oils (EOs) present high yield and are chemically constituted by complex mixtures or the predominance of main volatile constituents. The chemical composition of Piper EOs displays interspecific or intraspecific variations, according to the site of collection or seasonality. The main volatile compounds identified in Piper EOs are monoterpenes hydrocarbons, oxygenated monoterpenoids, sesquiterpene hydrocarbons, oxygenated sesquiterpenoids and large amounts of phenylpropanoids. In this review, we are reporting the biological potential of Piper EOs from the Neotropical region. There are many reports of Piper EOs as antimicrobial agents (fungi and bacteria), antiprotozoal (Leishmania spp., Plasmodium spp., and Trypanosoma spp.), acetylcholinesterase inhibitor, antinociceptive, anti-inflammatory and cytotoxic activity against different tumor cells lines (breast, leukemia, melanoma, gastric, among others). These studies can contribute to the rational and economic exploration of Piper species, once they have been identified as potent natural and alternative sources to treat human diseases.

Secondary Metabolic Profiles of Two Cultivars of Piper nigrum (Black Pepper) Resulting from Infection by Fusarium solani f. sp. piperis.

Bragantina and Cingapura are the main black pepper (Piper nigrum L.) cultivars and the Pará state is the largest producer in Brazil with about 90% of national production, representing the third largest production in the world. The infection of Fusarium solani f. sp. piperis, the causal agent of Fusarium disease in black pepper, was monitored on the cultivars Bragantina (susceptible) and Cingapura (tolerant), during 45 days' post infection (dpi). Gas Chromatography-Mass spectrometry (GC-MS) analysis of the volatile concentrates of both cultivars showed that the Bragantina responded with the production of higher contents of α-bisabolol at 21 dpi and a decrease of elemol, mostly at 30 dpi; while Cingapura displayed an decrease of δ-elemene production, except at 15 dpi. The phenolic content determined by the Folin Ciocalteu method showed an increase in the leaves of plants inoculated at 7 dpi (Bragantina) and 7-15 dpi (Cingapura); in the roots, the infection caused a phenolic content decrease in Bragantina cultivar at 45 dpi and an increase in the Cingapura cultivar at 15, 30 and 45 dpi. High Performance Liquid Chromatography-Mass spectrometry (HPLC-MS) analysis of the root extracts showed a qualitative variation of alkamides during infection. The results indicated that there is a possible relationship between secondary metabolites and tolerance against phytopathogens.

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.