Secretory structures in Baccharis platypoda DC. inflorescences (Asteraceae) and characterization of the chemical composition of its secretion.

Rocky outcrop environments at high altitudes have nutrient-poor soil, where species are exposed to water scarcity and high solar radiation. Baccharis platypoda DC. occurs in such an environment and has a rigid and transparent secretion that covers the entire inflorescence. We analysed and compared the secretory structures and their chemical composition in female and male inflorescences of B. platypoda, a dioecious species, to explore chemodiversity within this species and assess potential differences between individuals. Our investigation also aims to understand the occurrence of these substances in the genus Baccharis L. Chemical compounds and secretory structures were similar in female and male inflorescences. There are glandular trichomes on the epidermis of the abaxial surface of bracts, and secretory ducts in the axis of the inflorescence, as well as in sepals, petals, and bracts. Histochemical tests were positive for phenolic compounds, flavonoids, proteins, pectin, and lipids, but not for mucilage. Flavonoid content varied between 6.24% and 9.81%, being higher in female inflorescences. Chromatography revealed the presence of several phenolic compounds, some terpenes, and other less frequent classes in both female and male inflorescences. We highlight that trichomes found on these surfaces produce abundant phenolic compounds. These act as natural defence agents, absorbing UV radiation and minimizing oxidative stress to plant cells. The chemical composition of the secretion covering the inflorescences may reflect adaptation and survival mechanisms of these organisms under extreme sun exposure.

Pharmacological study of anti-inflammatory activity of aqueous extracts of Mikania glomerata (Spreng.) and Mikania laevigata (Sch. Bip. ex Baker).

ETHNOPHARMACOLOGICAL RELEVANCE: Mikania glomerata Spreng. (MG) and Mikania laevigata Sch. Bip. ex Baker (ML), popularly known as guaco, are medicinal plants similar in morphology, chemical composition and medicinal uses. Both species are often used and sold without distinction; however, it is believed that their chemical composition is different. AIM: Thus, the aim of this study is to investigate if the aqueous extract of MG and ML present similar anti-inflammatory activity to the point of being used interchangeably. MATERIAL AND METHODS: Different doses of both extracts and coumarin were given to rats in different experimental models to assess the anti-inflammatory activity between these two species. For this, the animals were submitted to paw edema, pleurisy and degranulation of peritoneal mast cell and the extracts were also characterized by Ultra High Efficiency Liquid Chromatography coupled to Mass Spectrometry (UHPLC-MS). RESULTS: The chromatographic method showed that ML presents ten times more coumarin than MG. Oral administration of MG, ML and coumarin inhibited paw edema induced by carrageenan (400 mg/kg, 55% inhibition; 400 mg/kg, 57% inhibition; 75 mg/kg, 38% inhibition; p < 0.05, respectively). MG, ML and coumarin treatment also inhibited the edema induced by compound 48/80 (400 mg/kg, 56% inhibition; 400 mg/kg, 69% inhibition; 75 mg/kg, 40% inhibition; p < 0.05, respectively). MG, ML and coumarin did not prevent mast cell degranulation and the consequent histamine release in Wistar rat peritoneal mast cells induced by compound 48/80. MG did not inhibit cell infiltration in pleurisy nor the highest dose tested, while ML decreased the leukocyte migration (200 and 400 mg/kg, 23% and 30% inhibition; p < 0.001, respectively) and, to a lesser extent, coumarin also reduced cell infiltration (10, 50 and 75 mg/kg; 15%, 16% and 17% inhibition; p < 0.001, respectively). CONCLUSION: The variation of the results of the anti-inflammatory activity found in M. glomerata and M. laevigata demonstrates that these two species should not be used interchangeably. Coumarin, as already proven, has anti-inflammatory action however, we have suggested that it probably is not the only component responsible for this therapeutic effect in the extracts.

Carbon disulfide formation in papaya under conditions of dithiocarbamate residue analysis.

Golden, Sunrise Solo and Tainung cultivars of papaya were found to release CS2 when submitted to experimental conditions of dithiocarbamate residue analysis. Three common analytical methods were used to quantitate CS2; one spectrophotometric method and two chromatographic methods. All three methods gave positive CS2 results for all three papaya varieties. Other endogenous compounds present in isooctane extracts of papaya fractions detected via gas chromatography (GC/ITD) using electron ionization (EI) were: carbonyl sulfide, dimethyl sulfide, carbon disulfide, 2-methylthiophene, 3-methylthiophene, 2-ethylthiophene, 3-ethylthiophene, benzylisothiocyanate, benzylthiocyanate and benzonitrile. Control samples were obtained from papaya plantations cultivated in experimental areas, in which no treatment with fungicides of the dithiocarbamate group was applied. Endogenous CS2 levels were compared with true dithiocarbamate residues measured in papaya samples from the field trials following applications of the mancozeb fungicide. Three days after application, true dithiocarbamate residues, measured by the procedure with isooctane partitioning and GC-ITD, were at the average level of 2 mg kg(-1).

Antimicrobial and cytotoxic activity of red propolis: an alert for its safe use.

AIMS: Red propolis is a resinous product popularly consumed in Brazil as it improves health, and it is considered a nutraceutical. The objective of this study was to test the antimicrobial activity of eight samples of red propolis from Brazil and Cuba to assess the possibility of application of this natural product as an antimicrobial agent, along with a study of its cytotoxic activity against non-tumor cell lines to evaluate at which concentrations it could be safely used. METHODS AND RESULTS: The chemical profile of the samples was evaluated by UHPLC-MS. All the samples presented antimicrobial activity which was tested using agar diffusion and serial dilution methods; and these samples displayed a better activity against most Gram-negative bacteria with minimum inhibitory concentration (MIC) in the range between 6·25 µg ml(-1) and 500 µg ml(-1). However our studies also revealed an inherent cytotoxic effect against HaCaT human keratinocytes and BALBc 3T3. CONCLUSIONS: To have a noncytotoxic and safe use of red propolis, it is necessary to use a concentration below the IC50 cytotoxic values. SIGNIFICANCE AND IMPACT OF THE STUDY: The traditional use of propolis does not necessarily guarantee its safety. The evaluation of the safety of bioactive natural products should always be considered together with the evaluation of the activity.

Convergence of a specialized root trait in plants from nutrient-impoverished soils: phosphorus-acquisition strategy in a nonmycorrhizal cactus.

In old, phosphorus (P)-impoverished habitats, root specializations such as cluster roots efficiently mobilize and acquire P by releasing large amounts of carboxylates in the rhizosphere. These specialized roots are rarely mycorrhizal. We investigated whether Discocactus placentiformis (Cactaceae), a common species in nutrient-poor campos rupestres over white sands, operates in the same way as other root specializations. Discocactus placentiformis showed no mycorrhizal colonization, but exhibited a sand-binding root specialization with rhizosheath formation. We first provide circumstantial evidence for carboxylate exudation in field material, based on its very high shoot manganese (Mn) concentrations, and then firm evidence, based on exudate analysis. We identified predominantly oxalic acid, but also malic, citric, lactic, succinic, fumaric, and malonic acids. When grown in nutrient solution with P concentrations ranging from 0 to 100 µM, we observed an increase in total carboxylate exudation with decreasing P supply, showing that P deficiency stimulated carboxylate release. Additionally, we tested P solubilization by citric, malic and oxalic acids, and found that they solubilized P from the strongly P-sorbing soil in its native habitat, when the acids were added in combination and in relatively low concentrations. We conclude that the sand-binding root specialization in this nonmycorrhizal cactus functions similar to that of cluster roots, which efficiently enhance P acquisition in other habitats with very low P availability.

Isolation and characterization of a degradation product of deflazacort.

Deflazacort (DFZ) is an oxazoline derivative of prednisolone with anti-inflammatory and immunosuppressive activity. The aim of this study was to investigate and to identify the main degradation product of DFZ, and to evaluate the anti-inflammatory effect of both DFZ and its major degradation product (namely DDP1). DFZ was subjected to alkaline and acid degradation. In 0.1 N NaOH, DFZ was immediately degraded and 99.0% of product DDP1 was detected by high performance liquid chromatography (HPLC). The HPLC method was ideal to separate the primary and other minor degradation products and was carried out using C18 column, mobile phase consisting of water: acetonitrile: (60:40, v/v) with flow rate of 1.0 mL/min and detection at 244 nm. DDP1 was isolated and identified as 21-hydroxy deflazacort (21-OH-DFZ) by NMR, IR and LCMS. The in vivo pharmacological assays showed that both DFZ as 21-OH-DFZ are active in in vivo and in vitro inflammatory models, but 21-OH-DFZ is more potent than DFZ.

Production of imidazole alkaloids in cell cultures of jaborandi as affected by the medium pH.

The effect of pH (from 4.8 to 9.8) on the production of pilosine and pilocarpine and on their partition between cell and medium was studied in two lineages (P and PP) of Pilocarpus microphyllus cell suspension cultures. Highest mass accumulation was observed at high pHs and both lineages produced pilocarpine while only lineage PP produced pilosine. Both alkaloids were released in the medium but higher accumulation occurred in the cells. The highest production of pilocarpine was at pH 8.8-9.8 in both cell lineages. Other imidazole alkaloids were also identified in both lineages. At all pHs tested, the pH in the media cultures tended to stabilize around 6 after 10-15 days of cultivation. NO3(-) and NH4+ variation in the media might partially explain the pH stabilization.

Cell suspension as a tool to study the biosynthesis of pilocarpine in Jaborandi.

Jaborandi (Pilocarpus microphyllus) is a species that naturally occurs in the North and Northeast of Brazil, whose leaves produce pilocarpine (an imidazole alkaloid that has been used to treat glaucoma and xerostomy), the biosynthesis of which is still uncertain. The aim of this work was to establish cell lineages and select them according to an alkaloid profile similar to the one from Jaborandi leaves. The induction of callus was done in different culture media and growth regulators. Calluses from primary cultures or those subcultured several times were used as explants for the obtainment of six cell lineages. Alkaloids content analyses and growth curves showed that lines obtained from primary cultures produced more alkaloids and a better development. Cell lines from 12 subcultures presented a decrease in pilocarpine and pilosine production. After 24 subcultures, the production of alkaloids remained constant. ESI-MS analysis showed that cell culture extracts have the same alkaloid composition as extracts made from leaves. The results indicate that cell suspensions can be used as a model to study the biosynthesis of the imidazole alkaloid in P. microphyllus.

Chemical composition and antimicrobial activity of the essential oil of Cordiaverbenacea D.C.

Cordiaverbenacea D.C. (Boraginaceae) is found along the coastal regions of Brazil, from the Amazon basin to the southernmost state of Rio Grande do Sul. The aerial parts of this plant have been used in folk medicine since colonial times for their anti-rheumatic, anti-inflammatory, analgesic and healing properties. The objectives of this study were: the extraction of the essential oil of the aerial parts of this species and quantification of the yield thereof; the identification and quantification of the principal components of the essential oil; and the determination of its antimicrobial activity by plate diffusion method. The yield of essential oil was 0.19% (v/w) in relation to the fresh flowering aerial parts and 0.23% (v/w) of the leaves. The main constituents of the essential oil, identified by gas chromatography/mass spectrometry (GC/MS), were alpha-pinene (29.69%), trans-caryophyllene (25.27%) and aloaromadendrene (9.99%). The Gram-positive bacteria and yeast tested were sensitive to the essential oil of Cordiaverbenacea D.C., but most of the Gram-negative bacteria were resistant.

Comparative study of in vitro methods used to analyse the activity of propolis extracts with different compositions against species of Candida.

AIMS: Propolis is known for its activity against micro-organisms and different in vitro assays have been used to evaluate this activity, frequently with contradictory results. METHODS AND RESULTS: Brazilian propolis from the state of São Paulo was extracted by maceration using different concentrations of ethanol and water. The resultant extracts were analysed by chromatographic methods. Several microbiological methods were compared to determine which one best evaluated the activity of the propolis extracts against species of Candida, with average minimal inhibitory concentration values between 6 and 12 mg ml(-1). CONCLUSIONS: Agar dilution in plates showed the clearest results. These were in agreement with the chromatographic analyses, which also identified the active substances. SIGNIFICANCE AND IMPACT OF THE STUDY: Although the active substances identified in this sample are typical of Brazilian propolis, their activity against Candida had not been recognized previously, demonstrating the importance of standardizing the correct combination of microbiological and chromatographic analyses.