Bioassay-guided isolation of α-glucosidase inhibitors from Byrsonima garcibarrigae Cuatrec

SUMMARY Introduction: Byrsonima garcibarrigae is an endemic tree of Amazonas state, Brazil, with pharmacological and chemical knowledge poorly understood. Aim: To investigate the antidiabetic potential of the B. garcibarrigae stem bark. Methods: The stem bark was sequentially extracted by maceration with hexane (EHBG), ethyl acetate (EABG), and methanol (EMBG). The antioxidant capacity, α-glucosidase inhibitory potentials and anti-glycation capacities were evaluated. A bio-guided fractionation gave compounds that were characterized by MS and NMR. Results: 8 compounds were identified by HPLC-MS. EMBG showed the highest α-glucosidase inhibitory activity (1.09±0.32 µg/mL), antioxidant activity (9.2±0.23 µg/mL) and phenolic compounds content (61.43±0.50%), thus was fractionated producing hexane (FHX), chloroform (FCL) and hydromethanolic (FHM) fractions. After additional anti- α-glucosidase assays, FHM (1.02±0.49 µg/mL) was fractionated giving quercitrin and epicatechin. The anti-glycation assay showed that EMBG, FHM and quercitrin presented higher activities in comparison to the positive control, amino-guanidine. Conclusions: B. garcibarrigae displayed antidiabetic potential since inhibited α-glucosidase, as well as presented expressive antioxidant and anti-glycation activities were recorded.

Introducción: Byrsonima garcibarrigae es un árbol endémico del estado de Amazonas, Brasil, con poco conocimiento farmacológico y químico. Objetivo: investigar el potencial antidiabético de la corteza del tallo de B. garcibarrigae. Métodos: la corteza del tallo se extrajo secuencialmente mediante maceración con hexano (EHBG), acetato de etilo (EABG) y metanol (EMBG). Se evaluó la capacidad antioxidante, los potenciales inhibidores de la α-glucosidasa y las capacidades anti-glicación. Un fraccionamiento bioguiado dio compuestos que se caracterizaron por MS y NMR. Resultados: se identificaron 8 compuestos mediante HPLC-MS. EMBG mostró la mayor actividad inhibidora de α-glucosidasa (1,09 ± 0,32 µg/mL), actividad antioxidante (9,2±0.23 µg/mL) y contenido de compuestos fenólicos (61,43 ± 0.50%), por lo que se fraccionó produciendo hexano (FHX), cloroformo (FCL) e hidrometanólicas (FHM). Después de ensayos adicionales de anti- α-glucosidasa, se fraccionó FHM (1,02 ± 0,49 µg/mL) dando quercitrina y epicatequina. El ensayo antiglicación mostró que EMBG, FHM y quercitrina presentaron actividades más altas en comparación con el control positivo, aminoguanidina. Conclusiones: B. garcibarrigae mostró potencial antidiabético ya que se registró una inhibición de la α-glucosidasa, así como también presentó actividades expresivas antioxidantes y antiglicación.

Introdução: Byrsonima garcibarrigae é uma árvore endêmica do estado do Amazonas, Brasil, com pouco conhecimento farmacológico e químico. Objetivo: investigar o potencial antidiabético da casca do caule de B. garcibarrigae. Métodos: a casca do caule foi extraída sequencialmente por maceração com hexano (EHBG), acetato de etila (EABG) e metanol (EMBG). A capacidade antioxidante, potencial inibibitório de α-glicosidase e capacidade antiglicação foram avaliadas. Um fracionamento bioguiado isolou compostos que foram caracterizados por MS e RMN. Resultados: 8 compostos foram identificados por HPLC-MS. O EMBG apresentou a maior atividade inibitória de α-glicosidase (1,09 ± 0,32 µg/mL), atividade antioxidante (9,2±0,23 µg/mL) e teor de compostos fenólicos (61,43 ± 0,50%), por isso foi fracionado produzindo hexano (FHX), clorofórmio (FCL) e hidrometanólico (FHM). Após ensaios anti- α-glicosidase adicionais, FHM (1,02 ± 0,49 µg/mL) foi fracionado, originando a quercitrina e epicatequina. O ensaio de antiglicação mostrou que EMBG, FHM e quercitrina exibiram atividades mais altas em comparação com o controle positivo, aminoguanidina. Conclusões: B. garci-barrigae apresentou potencial antidiabético, uma vez que foi registrada inibição da α-glicosidase, bem como expressiva atividade antioxidante e antiglicação.

Semisynthetic triterpenes led to the generation of selective antitrypanosomal lead compounds.

Triterpenes α,ß-amyrin are naturally occurring molecules that can serve as building blocks for synthesizing new chemical entities. This study synthesized acyl, carboxyesther, NSAID, and nitrogenous derivatives and evaluated their antimicrobial activity. A cyclodextrin complexation method was developed to improve the solubility of the derivatives. Of the 17 derivatives tested, five exhibited activity against Trypanosoma cruzi, T. brucei, Leishmania infantum, Candida albicans, Staphylococcus aureus, and Escherichia coli. The 9a/9b mixture showed weak activity against the parasites (IC50 24.45-40.32 µM). However, it showed no activity for the other microorganisms. Derivatives 14a/14b exhibited potent activity against T. cruzi (IC50 2.0 nM) in this tested concentration did not show activity to the other microorganisms and were not cytotoxic. Derivatives 15a/15b and 16a/16b demonstrated relevant activity against the parasites (IC50 2.24-5.44 µM), but were also cytotoxic. Derivatives 17a/17b showed low activity against the tested parasites (IC50 21.70-22.79 µM), but they were selective since they did not show activity against other microorganisms. In docking studies, in general, all derivatives showed complementarity with the CYP51 binding site of the trypanosomatid mainly by hydrophobic interactions; thus, it is not conclusive that the molecules act by inhibiting this enzyme. Our results showed that triterpenes derivatives with antitrypanosomal activity could be synthesized by an inexpensive and rapid method.

Anti-hyperglycemic, lipid-lowering, and anti-obesity effects of the triterpenes α and ß-amyrenones in vivo.

OBJECTIVE: Diabetes, obesity, and their associated metabolic disorders are public health problems that require prevention and new efficient drugs for treatment. We evaluated the anti-hyperglycemic, lipid-lowering, and anti-obesity effects of semisynthetic α, ß-amyrenones (ABA). MATERIALS AND METHODS: BALB/c mice were used for performing an acute model of oral carbohydrate and triglyceride tolerance, and in a streptozotocin-induced diabetes model, where glycemia and body weight changes were measured during ten days. C57BL/6 strain mice were used in the diet-induced obesity model, where lipidemia and body weight were measured during four weeks, and biochemical and histological parameters were analyzed after euthanasia. The doses considered in this study were 25, 50, and 100 mg/kg of ABA, used following some criteria for each experiment. RESULTS: ABA 25 mg/kg reduced the postprandial glycemia peak higher than acarbose 50 mg/kg (p<0.05). ABA 50 mg/kg significantly reduced glycemia in diabetic mice compared to acarbose 50 mg/kg (p<0.05). There was a reduction in the weight of the obese animals treated with ABA 25 and 50 mg/kg (p<0.05). ABA 50 mg/kg also significantly reduced lipidemia in these animals compared to orlistat 50 mg/kg. CONCLUSION: This study presents evidence of ABA's action in reducing postprandial glycemia and obesity in mice.

Dereplication and evaluation of the antinociceptive and anti-inflammatory activity of hydroethanolic extract of leaves from Campomanesia xanthocarpa O. Berg.

Campomanesia xanthocarpa popularly known as gabiroba is used as a medicinal plant for the treatment of inflammatory diseases, ulcers, among other uses, requiring studies to assist in proving these activities. In this study, the extract of leaves from C. xanthocarpa (CxHE) was submitted to assays of formalin-induced paw-licking, peritonitis induced by lipopolysaccharide and carrageenan-induced mechanical hyperalgesia tests. In chemical analysis, a preliminary phytochemical screening and the determination of phenol and flavonoid content were carried out, in addition to analysis by ESI-MS/MS system and HPLC-DAD system. The CxHE presented compounds such as tannins, triterpenoids, steroids and saponins and content of phenols (35.9 ± 1.3 GAE/g extract) and flavonoids (23.3 ± 2.1 mg EQ/g extract). Protocatechuic acid, gallic acid, ethyl gallate, quercetin, and 3-methyl epigallocatechin gallate, alpha and beta-amyrins were identified. CxHE at doses of 10-1000 mg/kg p.o. demonstrated anti-inflammatory and antinociceptive effects in all in vivo assays employed in this study. [Figure: see text].

Chemical Composition and Antioxidant, Antinociceptive, and Anti-inflammatory Activities of Four Amazonian Byrsonima Species.

Species of the Byrsonima genus are widely used in Brazil, especially for the treatment of gastrointestinal disorders. However, species from the Amazonian region are still poorly studied. Thus, we studied the antioxidant, antinociceptive, and anti-inflammatory activities of for Amazonian species, Byrsonima crispa, Byrsonima duckeana, Byrsonima garcibarrigae, and Byrsonima incarnata. Phenolic composition was determined by chemical and chromatographic methods. The aqueous extracts were evaluated in DPPH• , ABTS+• , and superoxide (O2•- ) tests, LPS-activated macrophage assay, and formalin test. All species contained a high phenolic and flavonoid content. We identified 15 phenolic compounds, including phenolic acids, hydroxycinnamic acids, flavonoids, and catechins. The extracts showed high antioxidant activity and were more active than quercetin at inhibiting nitric oxide release in the LPS-activated macrophage assay. B. duckeana and B. garcibarrigae showed higher in vivo antinociceptive and anti-inflammatory activities. B. garcibarrigae presented significant effect on the early phase of the formalin test, pointing to an antinociceptive mechanism distinct from traditional anti-inflammatory medicines. In conclusion, the pharmacological potential of these species is closely related to their flavonoid-rich chemical composition, which seems to act through antioxidant mechanisms. Copyright © 2017 John Wiley & Sons, Ltd.

Analgesic, Anti-Inflammatory, and Antioxidant Activities of Byrsonima duckeana W. R. Anderson (Malpighiaceae).

Background. Byrsonima is a promising neotropical genus, rich in flavonoids and triterpenes, with several proven pharmacological properties. Nevertheless, Byrsonima duckeana W. R. Anderson is an Amazonian species almost not studied. Objective. To assess the antioxidant, anti-inflammatory, and analgesic activities of Byrsonima duckeana leaves. Materials and Methods. We analyzed an ethanol extract and its fractions for polyphenol content and UHPLC-MS/MS, phosphomolybdenum, DPPH, TBARS antioxidant tests, formalin-induced pain, carrageenan-induced peritonitis, acetic acid-induced abdominal writhings, and hot plate assays. Results. All the samples showed high polyphenol content and antioxidant capacity in the phosphomolybdenum, DPPH, and TBARS tests. We identified ethyl gallate, quinic acid, gallic acid, catechin, epicatechin, quercetrin, and quercetin in the samples. B. duckeana was able to reduce leukocyte migration in the carrageenan-induced peritonitis by 43% and the licking time in the formalin test by 57%. In the acetic acid-induced writhing test, the chloroform (FCL) and ethyl acetate (FEA) fractions were the most active samples. FEA was selected for the hot plate test, where all the dosages tested (5, 50, and 200 mg·kg-1) showed significant analgesic activity. Conclusion. B. duckeana has interesting analgesic and antioxidant activities, due to its high phenolic content, especially phenolic acids.

Anti-inflammatory action of Justicia acuminatissima leaves

AbstractIn Amazonas State (Brazil), Justicia acuminatissima (Miq.) Bremek., Acanthaceae, leaf teas are used in folk medicine to treat several inflammatory illnesses. In order to validate this medicinal application, we analyzed the acute toxicity and antioxidant, antiedematogenic and antinociceptive potentials of an aqueous extract of this species, using culture cells and animal models. The aqueous extract did not cause toxic effects on human lymphocytes in high concentration (400 μg/ml), neither on mice treated with high doses (5000 mg/kg) in an acute toxicity analysis by oral route, and also did not cause lesions in the gastric mucosa of animals treated with 300 mg/kg, which was the maximal dose used in the anti-inflammatory screening. The aqueous extract caused inhibition of inflammatory pain in formalin-induced paw licking test with all tested doses, 30, 100 and 300 mg/kg, and antiedematogenic activity at 100 and 300 mg/kg. Additionally, the aqueous extract presented statistically significant action on the release of nitric oxide by lipopolysaccharide-activated macrophages. These results and other preliminary studies support the folk use of this species, and further investigation of its action mechanism by inhibition of COX-2 or related metabolite would be interesting.

Morphology and anatomy of Justicia acuminatissima leaves

Justicia acuminatissima (Miq.) Bremek., Acanthaceae, is a subshrub found in northern Brazil, where it is widely used by the population of this region as an anti-inflammatory medicine. Despite this popular use, there is no pharmacognostical data to support the correct identification of this species. We therefore performed a morpho-anatomical, histochemical and phytochemical analysis of the leaves of this species, using well-known methods. The leaves are simple, exstipulate, green on the surfaces, and pubescent, with a lanceolate shape, crenate margin, pinnate venation and decussate phyllotaxy. The parenchyma is palisade and spongy, and its vascular system is bilateral. Glandular and non-glandular trichome and cystoliths were also detected. There are diacytic stomata on both the adaxial and abaxial surfaces of epidermis. Histochemical tests revealed the presence of phenolic compounds, amide and protein. Phytochemical tests showed the presence of coumarins, tannins, catechins, saponins and steroids.

Anti-inflammatory, anti-hyperalgesic, antiplatelet and antiulcer activities of Byrsonima japurensis A. Juss. (Malpighiaceae).

ETHNOPHARMACOLOGICAL RELEVANCE: Decoctions or infusions of the stem bark of Byrsonima japurensis A. Juss. (Malpighiaceae) are widely used as an anti-inflammatory drug in folk medicine of Amazonas State (Brazil). AIM OF THE STUDY: To evaluate the pharmacological potential of an aqueous extract of the stem bark of Byrsonima japurensis (BJEA) to scientifically verify of its traditional use. MATERIALS AND METHODS: Anti-inflammatory, antihyperalgesic and antiulcer activities were evaluated in Wistar rats, a Hippocratic screening was performed in Swiss mice to evaluate the toxic effects, and antiplatelet evaluation was performed in human platelet rich plasma assay. Additionally, antioxidant activity was evaluated by superoxide radical scavenging method and ß-carotene bleaching test. RESULTS: Anti-inflammatory, antihyperalgesic and gastroprotective activities were observed in rats treated orally with different doses of BJEA. While signals of toxicity were observed in the mice treated with a very high dose of extract (5000mg/kg), no death occurred. BJEA also showed expressive antiplatelet and antioxidant activities in vitro. CONCLUSION: According to our results, it was concluded that stem bark of Byrsonima japurensis has significant and safe anti-inflammatory activity, which is closely related with their potent antioxidant activity, supporting the folk medicinal use of this species.

Estudo farmacognóstico e atividade in vitro sobre a coagulação sanguínea e agregação plaquetária das folhas de Passiflora nitida Kunth (Passifloraceae) / Pharmacognostic study and in vitro activity on blood coagulation and platelet aggregation of leaves of Passiflora nitida Kunth (Passifloraceae)

O gênero Passiflora (Passifloraceae) é utilizado principalmente para tratar doenças do SNC e cardiovasculares. A espécie Passiflora nitida Kunth é comumente conhecida como "maracujá-do-mato". A literatura relata o consumo in natura dos frutos desta espécie pela população local para distúrbios gastrointestinais. Considerando o potencial farmacológico do gênero, este trabalho teve por objetivo realizar estudo de caracterização fitoquímica desta espécie e estudar os efeitos dos extratos aquoso (EA), etanólico (EE) e hexânico (EH) de suas folhas sobre a coagulação sanguínea e agregação plaquetária. Para a caracterização fitoquímica foram realizados testes de cromatografia em camada delgada e ressonância magnética nuclear. O efeito dos extratos sobre a coagulação foi avaliado pelos testes de tempo de protrombina (TP) e tempo de tromboplastina parcial ativada (TTPa). O efeito sobre a agregação plaquetária foi avaliado em plasma rico em plaquetas por método espectrofotométrico, usando adenosina difosfato (ADP) e adrenalina (ADR) como indutores da agregação. Os extratos EA, EE e EH apresentaram atividade coagulante pelo teste do TP e o EE apresentou atividade anticoagulante para o TTPa. Quando induzidos por ADP, os extratos EA, EE e EH apresentaram valores de concentração inibitória 50% (CI50, µg/mL) de 450,5 ± 50,7; 511,2 ± 35,5 e 394,4 ± 8,9, respectivamente, e quando induzidos por ADR apresentaram valores de 438,7 ± 5,2; 21,0 ± 1,9 e 546,9 ± 49,9, respectivamente. O EE apresentou atividade inibitória sobre a agregação. A caracterização fitoquímica foi sugestiva da presença de flavonóides e cumarinas, aos quais podem ser atribuídos, em parte, os efeitos biológicos estudados.

The Passiflora genus (Passifloraceae) is mainly used to treat CNS and cardiovascular diseases. The Passiflora nitida Kunth species is commonly known as "maracujá-do-mato". The literature reports the in natura consumption of fruits of this species by the local population for gastrointestinal disorders. Considering the pharmacological potential of the genus, this work aimed to carry out study of phytochemical characterization of this species and study the effects of the aqueous (AE), ethanol (EE) and hexane (HE) extracts from its leaves on blood coagulation and platelet aggregation. Thin-layer chromatography and nuclear magnetic resonance were carried out for the phytochemical characterization. The effect of the extracts on the coagulation was evaluated by prothrombin time (PT) and activated partial thromboplastin time (aPTT) tests. The effect on the platelet aggregation was evaluated in platelet-rich plasma by spectrophotometric method, using adenosine diphosphate (ADP) and adrenaline (ADR) as inducers of aggregation. The AE, EE and HE extracts showed coagulant activity by the PT test, and the EE showed anticoagulant activity by the aPTT. When induced by ADP, the AE, EE and HE extracts showed 50% inhibitory concentration values (IC50, µg/mL) of 450.5 ± 50.7, 511.2 ± 35.5 and 394.4 ± 8.9, respectively, and when induced by ADR showed values of 438.7 ± 5.2, 21.0 ± 1.9 and 546.9 ± 49.9, respectively. The EE showed inhibitory effect on the aggregation. The phytochemical characterization was suggestive of the presence of flavonoids and coumarins, which can be attributed in part to the biological effects studied.