RESUMO
Parasitic weeds are noxious plants that damage crops of economic relevance, especially in Mediterranean and African countries. The strategy of suicidal germination was proposed to deal with this plague by using seed germination inducers that work as a pre-emergence herbicide and reduce the parasitic seed load before sowing. N-Substituted phthalimides with a furanone ring were found to be efficient in inducing the germination of Phelipanche ramosa and Orobanche cumana, two of the most problematic parasitic weeds of crops. However, the solubility of these compounds in water is low. A strategy for enhancing their aqueous solubility is the synthesis of host-guest complexes with cyclodextrins. Three bioactive phthalimide-lactones (PL01, PL04, and PL07) were selected and studied to form complexes of increased water solubility with α-, ß-, HP-ß-, and γ-cyclodextrin. The complexes obtained by the coprecipitation method, with increased aqueous solubility (up to 3.8 times), were studied for their bioactivity and they showed similar or slightly higher bioactivity than free phthalimide-lactones, even without the addition of organic solvents. A theoretical study using semiempirical calculations of molecular models including a solvation system confirmed the physicochemical empirical results. These results demonstrated that cyclodextrins can be used to improve the physicochemical and biological properties of parasitic seed germination inducers.
Assuntos
Ciclodextrinas , Plantas Daninhas , Humanos , Lactonas/química , Ftalimidas , AgriculturaRESUMO
Nitrogen (N) and phosphorus (P) are among the most important macronutrients for plant growth and development, and the most widely used as fertilizers. Understanding how plants sense and respond to N and P deficiency is essential to optimize and reduce the use of chemical fertilizers. Strigolactones (SLs) are phytohormones acting as modulators and sensors of plant responses to P deficiency. In the present work, we assess the potential role of SLs in N starvation and in the N-P signalling interplay. Physiological, transcriptional and metabolic responses were analysed in wild-type and SL-deficient tomato plants grown under different P and N regimes, and in plants treated with a short-term pulse of the synthetic SL analogue 2'-epi-GR24. The results evidence that plants prioritize N over P status by affecting SL biosynthesis. We also show that SLs modulate the expression of key regulatory genes of phosphate and nitrate signalling pathways, including the N-P integrators PHO2 and NIGT1/HHO. The results support a key role for SLs as sensors during early plant responses to both N and phosphate starvation and mediating the N-P signalling interplay, indicating that SLs are involved in more physiological processes than so far proposed.
Assuntos
Compostos Heterocíclicos com 3 Anéis/metabolismo , Lactonas/metabolismo , Nitrogênio/fisiologia , Fósforo/fisiologia , Transdução de Sinais , Solanum lycopersicum/fisiologiaRESUMO
A dereplication strategy using UPLC-QTOF/MSE, the HMAI method, and NMR spectroscopy led to the identification of five main steroidal saponins (1-5), including three previously unknown compounds named macroacanthosides A-C (3-5), in a bioactive fraction of Agave macroacantha. The major saponins were isolated, and some of them together with the saponin-rich fraction were then evaluated for phytotoxicity on a standard target species, Lactuca sativa. The inhibition values exhibited by the pure compounds were confirmed to be in agreement with the phytotoxicity of the saponin-rich fraction, which suggests that the saponin fraction could be applied successfully as an agrochemical without undergoing any further costly and/or time-consuming purification processes. The NMR data of the pure compounds as well as of those corresponding to the same compounds in the fraction were comparable, which indicated that the main saponins could be identified by means of this replication workflow and that no standards are required.
Assuntos
Agave/química , Saponinas/isolamento & purificação , Lactuca/efeitos dos fármacos , Lactuca/crescimento & desenvolvimento , Espectroscopia de Ressonância Magnética , Saponinas/química , Saponinas/toxicidadeRESUMO
C17-sesquiterpenoids are a group of natural products that have been recently discovered. These compounds have the peculiarity of lacking the α,ß-methylene butyrolactone system, which is known to be quite relevant for many of the biological activities reported for sesquiterpene lactones. Unfortunately, the biological interest of C17-sesquiterpenoids has not been studied in-depth, mainly due to the poor isolation yields in which they can be obtained from natural sources. Therefore, in order to allow a deeper study of these novel molecules, we have worked out a synthetic pathway that provides C17-sesquiterpenoids in enough quantities from easily accessible sesquiterpene lactones to enable a more thorough investigation of their bioactivities. With this synthesis method, we have successfully synthesized, for the first time, three natural C17-sesquiterpenoids, pertyolides A, B, and C, with good overall yields. Furthermore, we have also evaluated their phytotoxicity against etiolated wheat coleoptiles and corroborated that pertyolides B and C present strong phytotoxic activity.
Assuntos
Herbicidas/síntese química , Sesquiterpenos/toxicidade , Triticum/efeitos dos fármacos , Inula/química , Estrutura Molecular , Raízes de Plantas/química , Sesquiterpenos/síntese químicaRESUMO
INTRODUCTION: The analysis and detection of steroidal saponins is mainly performed using chromatographic techniques coupled with mass spectrometry. However, nuclear magnetic resonance (NMR) spectroscopy is a potential tool that can be combined with these techniques to obtain unambiguous structural characterisation. OBJECTIVE: This work provides a review of the carbon-13 (13 C)- and proton (1 H)-NMR spectroscopic data of aglycones from Agave saponins reported in the literature and also the development of an easy identification method for these natural products. METHODS: The database Scifinder was used for spectroscopic data collection in addition to data obtained from the Cadiz Allelopathy research group. The keywords used were Agave, spirostanic, furostanic, and saponin. RESULTS: The shielding variations produced by functional groups on the aglycone core and the structural features of the most representative aglycones from Agave species are described. The effects are additive for up to four long-range connectivities. A method for the identification of aglycones (HMAI) is proposed to classify aglycones from Agave spp. through the use of 1 H-NMR and heteronuclear multiple bond correlation (HMBC) experiments. CONCLUSIONS: The HMBC spectrum is representative of the structural features of aglycones from Agave spp. The HMBC method for aglycone identification (HMAI) method allowed the identification of pure saponins or mixtures thereof and this method can be used in combination with chromatographic techniques coupled with mass spectrometry to provide a more thorough analysis of Agave samples that contain aglycones.
Assuntos
Agave , Saponinas , Espectroscopia de Ressonância Magnética , Extratos VegetaisRESUMO
Yucca is one of the main sources of steroidal saponins, hence different extracts are commercialized for use as surfactant additives by beverage, animal feed, cosmetics or agricultural products. For a deeper understanding of the potential of the saponins that can be found in this genus, an exhaustive review of the structural characteristics, bioactivities and analytical methods that can be used with these compounds has been carried out, since there are no recent reviews on the matter. Thus, a total of 108 saponins from eight species of the genus Yucca have been described. Out of these, the bioactivity of 68 saponins derived from the isolation of Yucca or other genera has been evaluated. Regarding the evaluation and quality control of the saponins from this genus LC-MS technique is the most often used. Nevertheless, the development of methods for their routine analysis in commercial preparations are needed. Moreover, most of the studies found in the literature have been carried out on Y. schidigera extract, since is the most often used for commercial purposes. Only eight of the 50 species that belong to this genus have been studied, which clearly indicates that the identification of saponins present in Yucca genus is still an unresolved question.
Assuntos
Saponinas/química , Yucca/química , Glicosídeos/químicaRESUMO
Even today, weeds continue to be a considerable problem for agriculture. The application of synthetic herbicides produces serious environmental consequences, and crops suffer loss of their activity due to the appearance of new resistant weed biotypes. Our aim is to develop new effective natural herbicides that improve the problem of resistance and do not harm the environment. This work is focused on a bioassay-guided isolation and the characterization of natural products present in Moquiniastrum pulchrum leaves with phytotoxic activity and its preliminary application in weeds. Moquiniastrum pulchrum was selected for two reasons: it is an abundant species in the Cerrado region (the second most important ecosystem in Brazil, after the Amazon)-the explanation behind its being a dominant species is a major focus of interest-and it has traditional employment in folk medicine. Six major compounds were isolated in this plant: one flavone and five diterpenes, two of which are described for the first time in the literature. Four of the six compounds exhibited phytotoxic activity in the bioassays performed. The results confirmed the phytotoxic potential of this plant, which had not been investigated until now.
Assuntos
Asteraceae/química , Agentes de Controle Biológico/toxicidade , Diterpenos/toxicidade , Flavonas/toxicidade , Herbicidas/toxicidade , Plantas Daninhas/efeitos dos fármacos , Controle de Plantas Daninhas/métodos , Bioensaio , Agentes de Controle Biológico/química , Agentes de Controle Biológico/isolamento & purificação , Produtos Agrícolas/crescimento & desenvolvimento , Diterpenos/química , Diterpenos/isolamento & purificação , Flavonas/química , Flavonas/isolamento & purificação , Herbicidas/química , Herbicidas/isolamento & purificação , Humanos , Estrutura Molecular , Extratos Vegetais/química , Folhas de Planta/química , Plantas Daninhas/crescimento & desenvolvimentoRESUMO
Annona cherimola Mill., or the custard apple, is one of the species belonging to the Annonaceae family, is widely used in traditional medicine, and has been reported to be a valuable source of bioactive compounds. A unique class of secondary metabolites derived from this family are Annonaceous acetogenins, lipophilic polyketides considered to be amongst the most potent antitumor compounds. This review provides an overview of the chemical diversity, isolation procedures, bioactivity, modes of application and synthetic derivatives of acetogenins from A. cherimola Mill.
Assuntos
Acetogeninas/química , Acetogeninas/uso terapêutico , Annona/química , Acetogeninas/isolamento & purificação , Acetogeninas/farmacologia , Anticarcinógenos/farmacologia , Carboidratos/química , Micelas , Polímeros/químicaRESUMO
In the search of new alternatives for weed control, spices appear as an option with great potential. They are rich in bioactive natural products and edible, which might minimize toxicity hazard. Marjoram (Origanum majorana L.) is an aromatic herb that has been widely employed as a seasoning herb in Mediterranean countries. Although marjoram boasts a plethora of therapeutic properties (painkiller, antibiotic, treatment for intestinal disorders, etc.), the potential for its extracts for weed control is still to be more thoroughly explored. In order to determine their phytotoxic potential, marjoram leaves were subjected to different bioguided extraction processes, using water, ethyl acetate, acetone or methanol. The most active extract (acetone) was sequentially fractionated to identify its most active compounds. This fractionation led to the isolation and identification of 25 compounds that were classified as monoterpenes, diterpenes or flavonoids. Among them, a new compound named majoradiol and several compounds are described in marjoram for the first time. The phytotoxicity of the major compounds to etiolated wheat coleoptiles was compared against that of the commercial herbicide (Logran®), with similar or higher activity in some cases. These results confirm the extraordinary potential of the extracts from this edible plant to develop safer and more environmentally friendly herbicides.
Assuntos
Herbicidas/farmacologia , Origanum/química , Compostos Fitoquímicos/farmacologia , Fracionamento Químico , Flavonoides/química , Flavonoides/farmacologia , Herbicidas/química , Região do Mediterrâneo , Estrutura Molecular , Compostos Fitoquímicos/química , Folhas de Planta/química , Compostos de Sulfonilureia/farmacologia , Terpenos/química , Terpenos/farmacologia , Controle de Plantas DaninhasRESUMO
Aminophenoxazinones are degradation products resulting from the metabolism of different plant species, which comprise a family of natural products well known for their pharmacological activities. This review provides an overview of the pharmacological properties and applications proved by these compounds and their structural derivatives during 2000-2021. The bibliography was selected according to our purpose from the references obtained in a SciFinder database search for the Phx-3 structure (the base molecule of the aminophenoxazinones). Compounds Phx-1 and Phx-3 are among the most studied, especially as anticancer drugs for the treatment of gastric and colon cancer, glioblastoma and melanoma, among others types of relevant cancers. The main information available in the literature about their mechanisms is also described. Similarly, antibacterial, antifungal, antiviral and antiparasitic activities are presented, including species related directly or indirectly to significant diseases. Therefore, we present diverse compounds based on aminophenoxazinones with high potential as drugs, considering their levels of activity and few adverse effects.
Assuntos
Produtos Biológicos/farmacologia , Oxazinas/farmacologia , Animais , Antibacterianos/farmacologia , Antifúngicos/farmacologia , Antineoplásicos/farmacologia , Antivirais/farmacologia , Humanos , Neoplasias/tratamento farmacológico , Plantas/químicaRESUMO
Strigolactones (SLs) are important ex-planta signalling molecules in the rhizosphere, promoting the association with beneficial microorganisms, but also affecting plant interactions with harmful organisms. They are also plant hormones in-planta, acting as modulators of plant responses under nutrient-deficient conditions, mainly phosphate (Pi) starvation. In the present work, we investigate the potential role of SLs as regulators of early Pi starvation signalling in plants. A short-term pulse of the synthetic SL analogue 2'-epi-GR24 promoted SL accumulation and the expression of Pi starvation markers in tomato and wheat under Pi deprivation. 2'-epi-GR24 application also increased SL production and the expression of Pi starvation markers under normal Pi conditions, being its effect dependent on the endogenous SL levels. Remarkably, 2'-epi-GR24 also impacted the root metabolic profile under these conditions, promoting the levels of metabolites associated to plant responses to Pi limitation, thus partially mimicking the pattern observed under Pi deprivation. The results suggest an endogenous role for SLs as Pi starvation signals. In agreement with this idea, SL-deficient plants were less sensitive to this stress. Based on the results, we propose that SLs may act as early modulators of plant responses to P starvation.
Assuntos
Compostos Heterocíclicos com 3 Anéis/farmacologia , Lactonas/farmacologia , Fosfatos/deficiência , Raízes de Plantas/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Solanum lycopersicum/metabolismo , Raízes de Plantas/metabolismo , Triticum/metabolismoRESUMO
Vladimiria souliei is a plant found in China used in traditional medicine. Recent isolation studies have led to the discovery of vlasouliolides, which are natural sesquiterpene dimers. However, the yields obtained from isolation have proven to be really low (<0.01%), greatly hindering the study of these molecules. In this work, we propose a simple synthetic route to obtain different vlasouliolides in good yields from dehydrocostuslactone and costunolide, which will lead to further bioactivity studies at a higher scale.
Assuntos
Asteraceae , Sesquiterpenos de Eudesmano , Sesquiterpenos , China , Lactonas , Sesquiterpenos de GuaianoRESUMO
Weeds have been a major threat in agriculture for several generations as they lead to decreases in productivity and cause significant economic losses. Parasitic plants are a specific type of weed causing losses in crops of great relevance. A new strategy has emerged in the fight against parasitic plants, which is called 'suicidal germination' or the 'honey-pot strategy'. Regarding the problem of weed control from an ecological point of view, it is interesting to investigate new natural compounds with allelopathic activity with the aim of developing new natural herbicides that can inhibit the growth of weeds without damaging the environment. Safflower crops have been affected by parasitic plants and weeds and, as a consequence, the secondary metabolites exuded by safflower roots have been studied. The sesquiterpene lactone dehydrocostuslactone was isolated and characterised, and the structurally related costunolide was identified by UHPLC-MS/MS in safflower root exudates. These sesquiterpene lactones have been shown to stimulate germination of Phelipanche ramosa and Orobanche cumana seeds. In addition, these compounds were phytotoxic on three important weeds in agriculture, namely Lolium perenne, Lolium rigidum and Echinochloa crus-galli. The exudation of the strigolactones solanacol and fabacyl acetate have also been confirmed by UHPLC-MS/MS. The study reported here contributes to our knowledge of the ecological role played by some secondary metabolites. Moreover, this knowledge could help identify new models for the development of future agrochemicals based on natural products.
Assuntos
Carthamus tinctorius/parasitologia , Germinação/efeitos dos fármacos , Raízes de Plantas/parasitologia , Plantas Daninhas/efeitos dos fármacos , Controle de Plantas Daninhas/métodos , Alelopatia , Cromatografia Líquida , Lactonas/isolamento & purificação , Lactonas/farmacologia , Lolium/efeitos dos fármacos , Lolium/crescimento & desenvolvimento , Orobanche/efeitos dos fármacos , Orobanche/crescimento & desenvolvimento , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologia , Exsudatos de Plantas/isolamento & purificação , Exsudatos de Plantas/farmacologia , Raízes de Plantas/química , Sementes/efeitos dos fármacos , Sesquiterpenos/isolamento & purificação , Sesquiterpenos/farmacologia , Espectrometria de Massas em TandemRESUMO
We aimed to evaluate the bioherbicide potential of Eucalyptus saligna leaf litter essential oil, its fractions and major compounds. Six essential oil fractions were obtained by preparative thin-layer chromatography and analyzed by gas chromatography/mass spectrometry. Effects of the oil, its fractions and major compounds (1,8-cineole and/or α-pinene) diluted in aqueous solution were assessed on germination and seedling growth. Recipient species were Lactuca sativa (model), Amaranthus viridis (weed), Eragrostis plana (weed), and Paspalum notatum (forage). The essential oil was more phytotoxic on A. viridis and L. sativa, followed by E. plana, and caused no effects on P. notatum. Amaranthus viridis was inhibited by all treatments, mainly the essential oil, α-pinene and fraction 6, whereas E. plana was more affected by the oil fractions. Results revealed the species-specific phytotoxic effects of E. saligna essential oil, indicating its potential use for controlling A. viridis and E. plana. Phytotoxic effects of essential oils or their components should not be generalized, as effects may change according to recipient species.
Assuntos
Amaranthus/efeitos dos fármacos , Eragrostis/efeitos dos fármacos , Eucalyptus/química , Herbicidas/farmacologia , Óleos Voláteis/farmacologia , Folhas de Planta/química , Herbicidas/química , Herbicidas/isolamento & purificação , Óleos Voláteis/química , Óleos Voláteis/isolamento & purificação , Controle de Plantas DaninhasRESUMO
Annonaceous acetogenins (ACGs) are lipophilic polyketides isolated exclusively from Annonaceae. They are considered to be amongst the most potent antitumor compounds. Nevertheless, their applications are limited by their poor solubility. The isolation of ACGs from Annona cherimola leaves, an agricultural waste, has not been reported to date. Molvizarin (1) cherimolin-1 (2), motrilin (3), annonacin (4) and annonisin (5) are isolated for the first time from A. cherimola deciduous leaves. Annonacin was found to be four- and two-times more potent in tumoral cells (HeLa, 23.6% live cells; IGROV-1, 40.8% live cells for 24 h) than in HEK-293 at 50 µM (24 h, 87.2% live cells). Supramolecular polymer micelles (SMPMs) were synthesized to encapsulate the major ACG isolated, annonacin, in order to improve its solubility in aqueous media. The bioavailability of this compound was increased by a factor of 13 in a simulated human digestive system when compared with free annonacin and an encapsulation efficiency of 35% was achieved. In addition, the cytotoxic activity of SMPMs that hosted annonacin (100 µM, 24 h, 5.8% live cells) was increased compared with free annonacin in water (100 µM, 24 h, 92% live cells). These results highlight the use of by-products of A. cherimola, and their pure compounds, as a promising source of anticancer agents. The use of SMPMs as nanocarriers of ACGs could be an alternative for their application in food field as nutraceutical to enhance the administration and efficacy.
Assuntos
Acetogeninas/farmacologia , Annona/química , Antineoplásicos Fitogênicos/farmacologia , Nanopartículas/química , Folhas de Planta/química , Acetogeninas/química , Acetogeninas/isolamento & purificação , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/isolamento & purificação , Disponibilidade Biológica , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Portadores de Fármacos/química , Ensaios de Seleção de Medicamentos Antitumorais , Células HEK293 , Humanos , Estrutura MolecularRESUMO
11,13-Dehydro seco-guaianolides, a particular type of sesquiterpene lactones, were synthesized from the commercially available α-santonin (11) using a facile strategy involving a high-yielding photochemical reaction. Natural products 10 and 17 from Artemisia gorgonum were synthesized in good yields. Specifically, compound 10 was obtained in five steps with an overall yield of 17%. The sesquiterpene lactones were tested in the etiolated wheat coleoptile bioassay, and the most active compounds were assayed on standard target species. Guaianolide 13 showed the highest phytotoxic activities when compared with the known herbicide Logran.
Assuntos
Artemisia/efeitos dos fármacos , Plantas/efeitos dos fármacos , Sesquiterpenos de Guaiano/toxicidade , Bioensaio , Linhagem Celular Tumoral , Cristalografia por Raios X , Herbicidas/química , Humanos , Estrutura Molecular , Sesquiterpenos de Guaiano/química , Análise Espectral/métodos , Relação Estrutura-AtividadeRESUMO
A bioassay-guided phytochemical study of a Mimosa caesalpiniifolia leaf extract with antifungal activity permitted the identification of 28 compounds, including the new 6-(ß-boivinopyranosyl)apigenin (1), 8-(ß-oliopyranosyl)apigenin (2), (E)-6-(2-carboxyethenyl)apigenin (3), (E)-8-(2-carboxyethenyl)apigenin (4), and 7,5â³-anhydro-6-(α-2,6-dideoxy-5-hydroxyarabinohexopyranosyl)apigenin (5). The structures of the new compounds were determined by comprehensive spectroscopic analysis, including 1D and 2D NMR techniques, and by mass spectrometry. Compound 3 showed promising activity and selectivity against Candida krusei (IC50 44 nM), which exhibits resistance to azoles. The association of the major components 3-ß-d-glucopyranosyloxysitosterol (8) and ethyl gallate (10) was synergistic against C. krusei, especially the IC values of compound 10, which were reduced by more than 100-fold.
RESUMO
Capsaicinoids are reported to have a bunch of promising pharmacological activities, among them antibacterial effects against various strains of bacteria. In this study the effect on efflux pumps of mycobacteria was investigated. The importance of efflux pumps, and the inhibition of these, is rising due to their involvement in antibiotic resistance development. In order to draw structure and activity relationships we tested natural and synthetical capsaicinoids as well as synthetical capsinoids. In an accumulation assay these compounds were evaluated for their ability to accumulate ethidium bromide into mycobacterial cells, a well-known substrate for efflux pumps. Capsaicin and dihydrocapsaicin, the two most abundant capsaicinoids in Capsicum species, proved to be superior efflux pump inhibitors compared to the standard verapamil. A dilution series showed dose dependency of both compounds. The compound class of less pungent capsinoids qualified for further investigation as antibacterials against Mycobacterium smegmatis.
Assuntos
Amidas/farmacologia , Antibacterianos/farmacologia , Ésteres/farmacologia , Ácidos Graxos/farmacologia , Guaiacol/análogos & derivados , Guaiacol/farmacologia , Amidas/síntese química , Amidas/química , Antibacterianos/síntese química , Antibacterianos/química , Proteínas de Bactérias/antagonistas & inibidores , Capsaicina/análogos & derivados , Capsaicina/farmacologia , Ésteres/síntese química , Ésteres/química , Ácidos Graxos/síntese química , Ácidos Graxos/química , Guaiacol/síntese química , Proteínas de Membrana Transportadoras/metabolismo , Testes de Sensibilidade Microbiana , Estrutura Molecular , Mycobacterium smegmatis/efeitos dos fármacos , Relação Estrutura-AtividadeRESUMO
INTRODUCTION: Strigolactones (SLs) are the most representative germination stimulants for seeds of root parasitic plants, and they show activity even at concentrations below 10-10 M. The low amounts of stimulants produced by the host and their rapid degradability make it crucial to develop analytical methods with very low limits of quantification. OBJECTIVE: To develop a sensitive and validated analytical method for the simultaneous quantification of seven SLs [7-oxoorobanchyl acetate (1), solanacol (2), orobanchol (4), strigol (5), fabacyl acetate (6), orobanchyl acetate (7), and 5-deoxystrigol (8)]. METHODS: SLs were analysed using ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS), with (±)-GR24 (3) employed as internal standard (IS). Validation was based on selectivity, linearity, precision of the peak areas (repeatability and intermediate precision), detection and quantification limits, and stability. RESULTS: A simple, rapid and reliable UHPLC-MS/MS method has been validated for the routine analysis of seven SLs and has been successfully applied to quantify them in exudates and extracts from tomato roots (Solanum lycopersicum). The limits of quantifications range from 0.05 µg/L for 5-deoxystrigol to 0.96 µg/L for solanacol. CONCLUSION: The method provides a useful tool for research in all the fields related to SLs, both for studies related to their function as hormones, and signalling molecules in the rhizosphere, without sample preparation required for extracts and root exudates in less than 11 minutes.
Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Lactonas/análise , Extratos Vegetais/química , Raízes de Plantas/química , Solanum lycopersicum/química , Espectrometria de Massas em Tandem/métodos , Limite de DetecçãoRESUMO
A bio-guided study of leaf extracts allowed the isolation of two new macrobicyclic hydrolysable tannins, namely merianin A (1) and merianin B (2), and oct-1-en-3-yl ß-xylopyranosyl-(1"-6')-ß-glucopyranoside (3) from Meriania hernandoi, in addition to 11 known compounds reported for the first time in the Meriania genus. The structures were elucidated by spectroscopic analyses including one- and two-dimensional NMR techniques and mass spectrometry. The bioactivities of the compounds were determined by measuring the DPPH radical scavenging activity and by carrying out antioxidant power assays (FRAP), etiolated wheat coleoptile assays and phytotoxicity assays on the standard target species Lycopersicum esculentum W. (tomato). Compounds 1 and 2 exhibited the best free radical scavenging activities, with FRS50 values of 2.0 and 1.9 µM, respectively.