Sustainable and Biomimetic Methodology for Extraction of High-Value-Added Compounds in Almond Hulls.

Almond trees are the most cultivated nut tree in the world. The production of almonds generates large amounts of by-products, much of which goes unused. Herein, this study aimed to develop a green chemistry approach to identify and extract potentially valuable compounds from almond by-products. Initially, a screening was performed with 10 different Natural Deep Eutectic Solvents (NADESs). The mixture lactic acid/glycerol, with a molar ratio 1:1 (1:50 plant material to NADES (w/v) with 20% v/v of water) was identified as the best extraction solvent for catechin, caffeoylquinic acid, and condensed tannins in almond hulls. Subsequently, a method was optimized by a Design of Experiment (DoE) protocol using a miniaturized extraction technique, Microwave-Assisted Extraction (MAE), in conjunction with the chosen NADESs. The optimal conditions were found to be 70 °C with 15 min irradiation time. The optimal extraction conditions determined by the DoE were confirmed experimentally and compared to methods already established in the literature. With these conditions, the extraction of metabolites was 2.4 times higher, according to the increase in total peak area, than the established literature methods used. Additionally, by applying the multiparameter Analytical Greenness Metric (AGREE) and Green Analytical Process Index (GAPI) metrics, it was possible to conclude that the developed method was greener than the established literature methods as it includes various principles of green analytical chemistry.

Anti-Candida activity and biocompatibility of silver nanoparticles associated with denture glaze: a new approach to the management of denture stomatitis.

The association of silver nanoparticles (AgNps) to sealant agent Palaseal® can be a promising alternative for complete denture wearers who may develop denture stomatitis (DS). The study aimed to evaluate the anti-Candida and biocompatible potential of silver nanoparticles synthesized by three routes associated with denture glaze to prevent and/or treat oral candidiasis. Surface acrylic resin specimens were treated with different associations of glaze with AgNps (VER+AgUV, VER+AgTurk and VER+AgGm). As controls, specimens were treated with glaze+nystatin (VER+Nyst), glaze only (VER) or submerged in PBS (PBS). Afterwards, Candida albicans biofilm was developed for 24 h, 15 d and 30 d. Subsequently, the biofilm was quantified by CFU/mL, XTT assay and confocal laser scanning microscopy. Fibroblasts were submitted to conditioned medium with the same associations for 24, 48 and 72 h and LIVE/DEAD® viability test was carried out. Regardless of the period, there was a significant reduction (p < 0.01) of viable fungal cells load, as well as inhibition of fungal metabolic activity, in specimens treated with glaze+AgNps associations, compared to VER and PBS. The anti-Candida effects of the associations were similar to the VER+Nyst group, with emphasis on VER+AgGm, which showed the highest percentage values of non-viable fungal cells maintained over time. The associations did not prove toxicity to fibroblasts. The AgNps exerted antimicrobial activity against C. albicans biofilms and are biocompatible. The most effective results were achieved with the association of glaze+silver nanoparticles synthesized by the green chemistry method (AgGm), proving to be an innovative alternative in the management of DS.

Silver nanoparticles in denture adhesive: An antimicrobial approach against Candida albicans.

OBJECTIVE: To evaluate the antimicrobial potential of silver nanoparticles (Ag NPs) synthesized using three different routes (ultraviolet light, Turkevich, and green chemistry method using Glycine max extract) associated with COREGA® denture powder adhesive. METHODS: Heat-cured acrylic resin specimens were treated with different Ag NPs associated with the adhesive (AD + Ag UV, AD + Ag Turk, and AD + Ag Gm groups). As controls, the specimens were treated with a combination of adhesive and nystatin (AD + Nyst group), only adhesive (AD group), or submerged on the surface of the specimens (PBS group). After the treatments, biofilms of C. albicans developed for 3, 6, and 12 h on the specimen surfaces. The biofilm was quantified using colony-forming units per milliliter, colorimetric assay, and confocal laser scanning microscopy. RESULTS: Regardless of the period, we observed an inhibition of fungal load and a reduction in metabolic activity and biofilm mass in the resin specimens treated with the combinations AD/Ag NPs, compared to AD and PBS. The antimicrobial action of the AD + Turk and AD + Ag Gm groups was similar than that for the AD + Nyst group in all periods and viability tests, except for the biofilm mass (12 h). CONCLUSIONS: The COREGA® adhesive with Ag NPs, mainly those synthesized using the Turkevich and Glycine max methods, showed excellent antimicrobial activity against C. albicans biofilms, maintained for up to 12 h. CLINICAL SIGNIFICANCE: The association of Ag NPs to the adhesive can add preventive or therapeutic effects against denture stomatitis, to this prosthetic material.

Reaction of the Phytochemistry Community to Green Chemistry: Insights Obtained Since 1990.

This review article aims to study how phytochemists have reacted to green chemistry insights since 1990, the year when the U.S. Environmental Protection Agency launched the "Pollution Prevention Act". For each year in the period 1990 to 2019, three highly cited phytochemistry papers that provided enough information about the experimental procedures utilized were sampled. The "greenness" of these procedures was assessed, particularly for the use of solvents. The highly hazardous diethyl ether, benzene, and carbon tetrachloride did not appear in the papers sampled after 2010. Advances in terms of sustainability were observed mainly in the extraction stage. Similar progress was not observed in purification procedures, where chloroform, dichloromethane, and hexane regularly have been employed. Since replacing such solvents in purification procedures should be a major goal, potential alternative approaches are discussed. Moreover, some current initiatives toward a more sustainable phytochemical research considering aspects other than only solvents are highlighted. Although some advances have been achieved, it is believed that natural products chemists can play a major role in developing a novel ecological paradigm in chemistry. To contribute to this objective, six principles for performing natural products chemistry consistent with the guidelines of green chemistry are proposed.

A green and sustainable method for monitoring the chemical composition of soybean: an alternative for quality control.

INTRODUCTION: Soybean is one of the most important crops in the world, an important source of isoflavones, and used to treat various chronic diseases. High-performance liquid chromatography (HPLC), associated with multivariate experiments and green solvents, is increasingly used to develop comprehensive elution methods for quality control of plants and derivatives. OBJECTIVE: The work aims to establish a HPLC fingerprinting method for soybean seeds employing Green Chemistry Principles, a sustainable solvent with low toxicity, and a comprehensive experimental design that reduces the number of experiments. MATERIALS AND METHODS: The fingerprinting method was optimised through Design of Experiments by evaluating seven chromatographic variables: initial percentage of ethanol (X1), final percentage of ethanol (X2), temperature (X3), percentage of acetic acid in water (X4), flow rate (X5), run time (X6), and stationary phase (X7). The dependent variable was the number of peaks (n). RESULTS: An initial factorial design for screening purposes indicated that the most significant quantitative parameters to separate soybean metabolites were X1 and X3. The conditions were optimised by a Doehlert design, to obtain a HPLC-PAD (photodiode array detector) fingerprinting of the polar extract of soybean seeds with the markers identified by liquid chromatography electrospray ionisation tandem mass spectrometry (LC-ESI-MS/MS). The optimum fingerprinting method was determined as 5-55% of ethanol in 30 min, at 35°C, and flow rate of 1 mL/min, by employing a phenyl-hexyl column (150 mm × 4.6 mm). CONCLUSION: The developed green method enabled markers of soybean to be separated and identified and could be an eco-friendlier alternative for soybean quality control that covered seven Green Analytical Chemistry Principles.

A green, simplified, and efficient experimental setup for a high-throughput screening of agri-food by-products - From polar to nonpolar metabolites in sugarcane solid residues.

From an environmental perspective, searching for useful compounds in agri-food by-products by employing inefficient and polluting analytical procedures is paradoxical. This work aimed to develop a green, simplified, and highly efficient experimental setup for extracting and tentatively identifying the broadest range of metabolites in sugarcane solid by-products collected directly within the industrial mills. Nine different extraction approaches were investigated side-by-side, including three reference methods. Based on the extraction and environmental performances assessed by two complementary metrics called Analytical-Eco Scale and the Analytical Greenness Calculator, it was possible to reach two highly efficient two liquid-phase extractions while avoiding harmful solvents and traditional time, energy, and solvent consuming sample preparation steps, such as solvent evaporation, metabolite concentration, re-suspension, and derivatization. The simultaneously produced hydroethanolic and n-heptane extracts were directly analyzed by ultra-high-performance liquid chromatography and gas chromatography, both coupled to mass spectrometry, respectively, leading to the annotation of a large dynamic range of compounds from information rich spectral data. Up to 111 metabolites were identified in a single matrix, from highly polar sucrose to nonpolar wax ester C53 in a single extraction. Orientin, apigenin-6-C-glucosylrhamnoside, 1-octacosanol, octacosanal, and other bioactive compounds were identified in these abundantly available by-products, which are currently just burned to produce energy. The best two methods developed here (Two-Liquid-Phase Ultrasound-Assisted Extraction with Probe and Two-Liquid-Phase Dynamic Maceration) appeared as a green, simplified, and highly efficient procedures to qualitatively profile metabolites in complex solid matrices.

Soya agricultural waste as a rich source of isoflavones.

Soybeans are among the world's major crops responsible for food and biodiesel production, as well as a major source of isoflavones - a class of high value-added bioactive compounds. As estimated 460 million tonnes of soya residues (branches, leaves, roots, and pods) will be produced in the 2018/2019 harvest, and 20-40% of this waste must be removed from the field to ensure soil quality and minimize environmental impacts. This work investigated the potential occurrence and content of isoflavones in soya agricultural waste collected directly from the ground after mechanically harvesting. We also assessed the extraction performances of ethanol and acetone for these materials as an alternative to acetonitrile, a problematic solvent from an environmental point of view. Considerable amounts of isoflavones were found in soya agricultural waste collected directly from the ground when compared to soybeans (2.71 ± 0.27, 0.57 ± 0.1, 0.30 ± 0.05 and 2.09 ± 0.24 kg of isoflavones/tonne of leaves, branches, pods, and soybeans, respectively). The greener ethanol and acetone performed well for a broad range of compounds. This is an example in which appreciable amounts of high value-added compounds are wasted. Since isoflavones are considered phytoestrogens, their recovery from part of this waste might avoid potential contamination of soil and groundwater.

Qualitative and Quantitative Analysis of Ethanolic Extract and Phenolic Fraction of Jatropha aethiopica (Euphorbiaceae) Leaves and Their Hypoglycemic Potential.

Although Jatropha aethiopica, popularly known in Cuba as "mata diabetes", is used in salads and as a dietary supplement, its chemical composition and antidiabetic properties yet remains unclear. In this work, we evaluate the qualitative and quantitative composition of ethanolic extract (EE) and phenolic fraction (PF) of Jatropha aethiopica leaves and their hypoglycemic and hypolipidemic activity. Chemical fractionation of the ethanolic extract yielded nine compounds, which included protocatechuic acid (1), chlorogenic acid (2), caffeic acid (3), quercetin 3-O-α-l-rhamnopyranosyl-(1 → 2)-[α-l-rhamnopyranolsyl-(1 → 6)]-ß-d-galactopyranoside (4), a new kaempferol 3-O-α-l-rhamnopyranosyl-(1 → 4)-[α-l-rhamnopyranolsyl-(1 → 6)]-ß-d-galactopyranoside (5), kaempferol 3-O-α-l-rhamnopyranosyl-(1 → 2)-[α-l-rhamnopyranolsyl-(1 → 6)]-ß-d-glucopyranoside (6), rutin (7), kaempferol 3-O-α-l-rhamnopyranosyl-(1 → 6)-ß-d-glucopyranoside (8), and quercetin (9). The compounds (1, 4-7) were quantified by high-performance liquid chromatography photodiode array detection (HPLC-PDA) in both the ethanolic extract (62.65 ± 0.15 mg/g) and phenolic fraction (61.72 ± 0.23 mg/g). The results obtained show that both ethanolic extract and phenolic fraction contributed toward the improvement of glucose tolerance, which in turn led to a decline in the glucose levels. Remarkably, the ethanolic extract presented a relatively higher promising effect compared to metformin.

Operculina macrocarpa: chemical and intestinal motility effect in mice

ABSTRACT Operculina macrocarpa (L.) Urb., Convolvulaceae, is used by the population as a laxative. In this work we described the isolation of the three phenolic acids present in the hydroethanolic extract of the O. macrocarpa roots. The quantification of the caffeic, chlorogenic acids and of the new caffeic dimer in the hydroethanolic and infusion extracts was performed by high-performance liquid chromatography coupled photodiode array detector. These analyses showed the higher content of the chlorogenic, caffeic and the new 3,4'-dehydrodicaffeic acid in hydroethanolic and hydroethanolic extracts without resin in which infusion. The acid found in greater quantity is caffeic acid followed by the 3,4'-dehydrodicaffeic acid. The laxative activity was evaluated by different experimental models of intestinal transit with the hydroethanolic and infusion extracts, and the resin fraction, caffeic, chlorogenic and ferulic acids. The results showed all extracts and compounds tested had significant activity in the experimental model tested. These results obtained are essential for the future development of a pharmaceutical product with safety and efficacy.

The Anti-Inflammatory Effects of the Methanolic Extract and Fractions from Davilla elliptica St. Hil. (Dilleniaceae) on Bothrops jararaca Envenomation.

Inflammation and haemorrhage are the main characteristics of tissue injury in botropic envenomation. Although some studies have shown that anti-venom prevents systemic reactions, it is not efficient in preventing tissue injury at the site of the bite. Therefore, this work was undertaken to investigate the anti-inflammatory effects of the methanolic extract and fractions from D. elliptica and to evaluate the role of matrix metalloproteinases (MMPs) in this process. Effects of the extract and fractions from D. elliptica were evaluated using a carrageenan-induced paw oedema model in rats, and leukocyte rolling was visualized by intravital. The quantification of MMPs activities (MMP-2 and MMP-9) extracted from the dermis of mice treated with extract and fractions alone or incubated with venom was determined by zymographic analyses. Our results show that intraperitoneal (i.p.) injection of fractions significantly reduced paw oedema after the carrageenan challenge. Treatment with the tannins fraction also resulted in considerable inhibition of the rolling of leukocytes and this fraction was able to decrease the activation of MMP-9. These results confirmed the anti-inflammatory activity of the methanolic extract and tannins fraction of D. elliptica and showed that the dermonecrosis properties of B. jararaca venom might be mediated through the inhibition of MMP-9 activity.

Investigation on the effects of guava (Psidium guajava L.) infusions on germination, root tips and meristematic cells of Latuca sativa.

Guava (Psidium guajava L.) is a plant often employed in popular medicine. Recently several studies have alerted about the toxicity of substances present in medicinal plants, which can pose risks to the human health. In this sense, the present work aimed to investigate the phytotoxic, cytotoxic and genotoxic action of three guava varieties - Paluma, Pedro Sato and Roxa ("purple") - on the plant test system Lactuca sativa L. Thus, macro- and microscopic evaluations were carried out for five infusion concentrations (2.5, 5.0, 10.0, 20.0 and 40.0 g.L(-1)) prepared from each variety. Distilled water was used as negative control. Chromatographic and spectroscopic analysis by HPLC-PAD indicated that the chemical composition of the infusion of Roxa is different than that of the infusions of the varieties Paluma and Pedro Sato. It was observed that seed germination and root growth in L. sativa exposed to infusions decreased with increasing infusion concentration, regardless of the tested cultivar. For the mitotic index, no statistical differences were observed. On the other hand, a significant increase in the frequency of cell cycle alterations was verified, especially for the highest concentrations tested. The cytogenotoxic effect was significant. Therefore, guava should not be used indiscriminately in popular medicine.

Flavonoid detection in hydroethanolic extract of Pouteria torta (Sapotaceae) leaves by HPLC-DAD and the determination of its mutagenic activity.

It is well known that phytotherapy has grown in popularity in recent years. Because a drug cannot be administered without ensuring its effectiveness and safety, the standardization and regulation of phytotherapeutic drugs are required by the global market and governmental authorities. This article describes a simple and reliable high-performance liquid chromatography-diode array detection analysis method for the simultaneous detection of myricetin-3-O-ß-D-galactopyranoside, myricetin-3-O-α-L-arabinopyranoside, and myricetin-3-O-α-L-rhaminopyranoside present in the hydroethanolic extract (ethanol/H2O, 7:3, v/v) of Pouteria torta. The mutagenic activity of the extract was evaluated on Salmonella typhimurium and by an in vivo micronucleus test on the peripheral blood cells of Swiss mice. The linearity, sensitivity, selectivity, repeatability, accuracy, and precision of the assay were evaluated. The analytical curves were linear and exhibited good repeatability (with a deviation of less than 5%) and demonstrated good recovery (within the 83-107% range). The results demonstrate that the hydroethanolic extract exhibited a mutagenic activity in both assays, suggesting caution in the use of this plant in folk medicine.

Composição química e atividade alelopática do óleo essencial de eucalipto / Chemical composition and allelopathic activity of the eucalyptus essential oil

Os óleos essenciais constituem um tipo de metabólito secundário de grande importância econômica e estão sendo cada vez mais estudados e utilizados como potentes inibidores de sementes e do crescimento de diversas plantas. O presente trabalho teve por objetivo a análise química qualitativa e quantitativa bem como a avaliação da atividade alelopática do óleo essencial extraído das folhas frescas de eucalipto (Eucalyptus citriodora) sobre a germinação e o desenvolvimento radicular das sementes de sorgo (Sorghum bicolor L.) e pepino (Cucumis sativus L.), cultivados em placa de Petri. O óleo essencial foi obtido por hidrodestilação, utilizando um aparelho tipo Clevenger, e analisado por cromatografia em fase gasosa com detector de ionização de chama e espectrometria de massas. Foi possível identificar doze constituintes químicos correspondendo a 97,69%, com predominância dos monoterpenos oxigenados citronelal (64,92%) e iso-isopulegol (10,20%) e do citronelol (8,25%). Os ensaios biológicos utilizando o óleo essencial mostraram que o mesmo apresenta efeito alelopático, prejudicando a germinação e o desenvolvimento da radícula das sementes de sorgo e pepino, sendo a redução da germinação mais pronunciada no sorgo, e que o aumento da concentração do óleo leva a uma redução linear na capacidade germinativa e no desenvolvimento da radícula.

Essential oils consist of a type of secondary metabolite that holds great economic importance, they have been increasingly studied and used as potent inhibitors of seeds and growth of various plants. The present work aimed at the qualitative and quantitative chemical analysis and evaluation of the allelopathic activity of the essential oil extracted from fresh leaves of eucalyptus (Eucalyptus citriodora) over the germination and root development of seeds of sorghum (Sorghum bicolor L.) and cucumber (Cucumis sativus L.), grown in a Petri dish. The essential oil was obtained by steam distillation, using a Clevenger apparatus, and analyzed by chromatography in gas phase with flame ionization detector and mass spectrometry. It was possible to identify twelve chemical constituents corresponding to 97.69%, with predominance of oxygenated monoterpenes citronellal (64.92%) and iso-isopulegol (10.20%) and citronellol (8.25%). The biological essays using the essential oil showed the presence of an allelopathic effect, affecting the germination and radicule length of sorghum and cucumber seeds, the germination reduction being more pronounced in sorghum, also the increase of the oil concentration leads to a linear decrease in the germination and in the radicule length.

Interconverting flavanone glucosides and other phenolic compounds in Lippia salviaefolia Cham. ethanol extracts.

Four interconverting flavanone glycosides [(2R)- and (2S)-3',4',5,6-tetrahydroxyflavanone 7-O-ß-D-glucopyranoside, and (2R)- and (2S)-3',4',5,8-tetrahydroxyflavanone 7-O-ß-D-glucopyranoside], in addition to eight known flavonoids [naringenin, asebogenin, sakuranetin, 6-hydroxyluteolin 7-O-ß-D-glucoside, (2R)- and (2S)-eriodictyol 7-O-ß-D-glucopyranoside, aromadendrin and phloretin], three phenylpropanoid glycosides [forsythoside B, alyssonoside and verbascoside] and the epoxylignan lariciresinol 4'-O-ß-D-glucopyranoside were isolated and identified in the EtOH extract of the aerial parts of Lippia salviaefolia Cham. The phytochemical study herein was guided by preliminary antioxidant tests, namely, ß-carotene protection and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity. The crude extracts, their active fractions and the isolated compounds were assayed against intracellular reactive oxygen species (ROS) and human embryonic kidney HEK-293 and human melanoma M14 cancer cell growth. Aromadendrin and phloretin were able to counteract elevation of ROS induced by the oxidant t-butylhydroperoxide (t-BOOH) in HEK-293 cells, whereas phloretin strongly protected HEK-293 cells from ROS damage at 1 µM. Additionally, phloretin exhibited a significant growth inhibitory effect at 20-40 µM in both HEK-293 and M14 cells and induced a concentration dependent apoptosis at 20 µM in M14 cells, suggesting a selective action towards malignant cells. Due to their equilibria, the four interconverting flavanone glycosides were studied using 1D and 2D NMR, HPLC-CD-PDA and HRMS analyses.

Secondary metabolites of Miconia rubiginosa.

The Miconia genus is the most representative of the Melastomataceae family, and some species are commonly used in Brazilian folk medicine as anti-inflammatory agents. In this work we investigated the leaves from Miconia rubiginosa (Bonpl.) DC, using high-speed countercurrent chromatography, which yielded 11 substances (eight flavonoids, gallic acid, casuarictin, and schizandriside). Identification was achieved using nuclear magnetic resonance spectroscopy and high-performance liquid chromatography-circular dichroism-diode array detection analyses.

Absolute configuration and selective trypanocidal activity of gaudichaudianic acid enantiomers.

Gaudichaudianic acid, a prenylated chromene isolated from Piper gaudichaudianum, has been described as a potent trypanocidal compound against the Y-strain of Trypanosoma cruzi. We herein describe its isolation as a racemic mixture followed by enantiomeric resolution using chiral HPLC and determination of the absolute configuration of the enantiomers as (+)-S and (-)-R by means of a combination of electronic and vibrational circular dichroism using density functional theory calculations. Investigation of the EtOAc extract of the roots, stems, and leaves from both adult specimens and seedlings of P. gaudichaudianum revealed that gaudichaudianic acid is biosynthesized as a racemic mixture from the seedling stage onward. Moreover, gaudichaudianic acid was found exclusively in the roots of seedlings, while it is present in all organs of the adult plant. Trypanocidal assays indicated that the (+)-enantiomer was more active than its antipode. Interestingly, mixtures of enantiomers showed a synergistic effect, with the racemic mixture being the most active.

Assessment of DNA damage induced by extracts, fractions and isolated compounds of Davilla nitida and Davilla elliptica (Dilleniaceae).

Davilla nitida and Davilla elliptica (Dilleniaceae) are plants that occur predominantly in the cerrado region of South America. They are used in popular medicine to treat stomach diseases, diarrhea and swelling, particularly of the lymph nodes and testicles. Chemical investigation of these two plant species led to the identification of the compounds myricetin-3-O-α-l-rhamnoside (myricitrin), quercetin-3-O-α-l-rhamnoside (quercitrin), myricetin, quercetin and gallic acid derivatives in the leaves of D. nitida and D. elliptica. Therefore, it was concluded that the two species of Davilla possess qualitatively similar chemical profiles. In the present study, the mutagenic and genotoxic potential of these plants and of their isolated compounds was tested in the Salmonella typhimurium assay (Ames test) with strains TA100, TA98, TA102 and TA97a, in the micronucleus test with peripheral blood cells of mice treated in vivo, and in plasmid DNA to analyze DNA strand-breaks. In the assessment of mutagenic potential by the Ames test, extracts from both plant species and a D. nitida ethyl-acetate fraction induced positive responses. On the other hand, none of the extracts showed genotoxic activity in the mouse cells. In the presence of metal ion, D. nitida and D. elliptica aqueous and ethyl-acetate fractions, as well as their isolated compounds, induced single- and double-strand-breaks in plasmid DNA in a cell-free system.

Determination of catechin diastereomers from the leaves of Byrsonima species using chiral HPLC-PAD-CD.

When catechins are found in plant extracts, they are almost always identified as catechin and/or epicatechin probably due to stereoselectivity of the enzymes involved in the biosynthesis of these substances. However, the lack of reports regarding to ent-catechin as well as ent-epicatechin does not necessarily mean that these compounds have not been produced. In fact, most of the previous reports used chromatographic conditions not suitable for such separation. This article describes a simple and reliable analytical HPLC-PAD-CD method for simultaneous determination of catechin diastereomers both in infusions and extracts from the leaves of Byrsonima species. The direct separation of catechin, ent-catechin, epicatechin, and ent-epicatechin was obtained in normal phase by HPLC-PAD-CD using Chiralcel OD-H as chiral stationary phase and n-hexane/ethanol with 0.1% of TFA as mobile phase.

Davilla elliptica and Davilla nitida: gastroprotective, anti-inflammatory immunomodulatory and anti-Helicobacter pylori action.

ETHNOPHARMACOLOGICAL RELEVANCE: Davilla elliptica and Davilla nitida are species commonly found in the Brazilian Cerrado biome. AIM OF THE STUDY: Based on ethnopharmacological and phytochemical analyses, methanolic extracts from leaves of Davilla elliptica (EDE) and Davilla nitida (EDN) were evaluated for their anti-ulcer, anti-inflammatory, immunological and anti-Helicobacter pylori activities. MATERIALS AND METHODS: The gastroprotective action of both extracts was evaluated in rodent experimental models (HCl/ethanol, ethanol or NSAID). We also evaluated anti-inflammatory (carrageenin-induced rat hind paw edema), immunomodulatory (murine peritoneal macrophages) and antibacterial action of both extracts against a standard strain of Helicobacter pylori. RESULTS: EDE and EDN (500 mg/kg) were able to protect gastric mucosa against HCl/ethanol solution (EDE 63%; EDN 59%), absolute ethanol (EDE 95%; EDN 88%), and also against injurious effect of NSAID (EDE 77%; EDN 67%). When EDE and EDN were challenged with sulfhydryl depleter compound, the gastroprotective action of both extracts was completely abolished. EDE had gastroprotective effect related to increase of glutathione bioavailability and stimulated higher levels of NO, H2O2 and TNF-alpha production. Otherwise EDN showed better anti-Helicobacter pylori action than EDE. Neither extracts presented anti-inflammatory activity by oral route. CONCLUSION: The phytochemical investigation showed that both extracts possess phenolic acid derivatives, acylglycoflavonoids and condensed tannins with evident quantitative variations that probably influenced the pharmacological differences between extracts.

Resolution and absolute configuration assignment of a natural racemic chromane from Peperomia obtusifolia (Piperaceae).

The resolution of the natural racemic chromane 3,4-dihydro-5-hydroxy-2,7-dimethyl-8-(3''-methyl-2''-butenyl)-2-(4'-methyl-1',3'-pentadienyl)-2H-1-benzopyran-6-carboxylic acid (1) isolated from the leaves of Peperomia obtusifolia has been accomplished using stereoselective HPLC. The absolute configuration of the resolved enantiomers was determined by the analysis of optical rotations and CD spectra. The finding of a racemic mixture instead of an enantiomerically pure metabolite raises questions about the final steps in the biosynthesis of this class of natural products, suggesting that the intramolecular chromane ring formation step may not be enzymatically controlled at all in P. obtusifolia.