Cucurbitacins and the Immune System: Update in Research on Anti- inflammatory, Antioxidant, and Immunomodulatory Mechanisms.

Cucurbitacins are a wide group of natural products found in several plant families, especially in the Cucurbitaceae family. In the last decade, there has been a significant increase in studies aimed at identifying new biological activities of cucurbitacins and describing their mechanisms of action. The most researched pharmacological activities are antineoplastic and anti-inflammatory activity, the first being recently reviewed. The present review explains the anti-inflammatory, antioxidant, and immunomodulatory potential of cucurbitacins, identifying the most studied compounds in this area and exploring their mechanisms of action already studied. A brief report was made about the main structural characteristics of cucurbitacins, in addition to an update on the biological activities attributed to this class in the last 5 years. Cucurbitacin B and cucurbitacin E have been identified as the most investigated when it comes to the immune response, playing roles in both innate and adaptive immunity. The most cited mechanisms were inhibition of COX-2 and NOS, reduction of oxidative stress, suppression of proinflammatory cytokines and modulation of acquired immunity proteins. It was found that cucurbitacins are promising molecules in the search for therapeutic innovation and have wide versatility in the immune response.

Bioguided Isolation of Alkaloids and Pharmacological Effects of the Total Alkaloid Fraction from Aspidosperma pyrifolium Mart. (Apocynaceae).

Aspidosperma pyrifolium is used in traditional medicine to treat inflammatory disorders. The aim of the study was to perform phytochemical characterization and evaluate the anti-inflammatory, anti-nociceptive and acute toxicity effects of the total alkaloid fraction (TAF-Ap) from stem barks. Two monoterpenic indole alkaloids were isolated by high performance liquid chromatography coupled with mass spectrometry (HPLC-MS) and the structural elucidation was performed using 1D and 2D NMR analysis. As for toxicity, no animals died at 50 mg kg-1 and this concentration presented mild sedation and forced breathing within the first 24 h. The lethal dose capable of killing 50% of the animals (LD50) was estimated to be 160 mg kg-1. In the pharmacological tests, the models used were 1% carrageenan-induced paw edema and peritonitis, 1% formalin-induced nociception and 1% acetic acid-induced abdominal writhing in Swiss mice. The study made it possible to isolate 15-methoxyaspidospermine and 15-methoxypyrifolidine, corroborating the results of pharmacological assays, which showed anti-inflammatory and analgesic potential, especially at 30 mg kg-1 (p < 0.001). Thus, the species was shown to be a promising source of active substances, with special attention paid to its toxicological potential.

Bioguided Purification of Active Compounds from Leaves of Anadenanthera colubrina var. cebil (Griseb.) Altschul.

Anadenanthera colubrina var cebil (Griseb.) Altschul is a medicinal plant found throughout the Brazilian semi-arid area. This work performed a bioguided purification of active substances present in ethyl acetate extract from A. colubrina leaves. The anti-Staphylococcus aureus and antioxidant actions were used as markers of bioactivity. The extract was subjected to flash chromatography resulting in five fractions (F1, F2, F3, F4, and F5). The fractions F2 and F4 presented the highest antimicrobial action, with a dose able to inhibit 50% of bacteria growth (IN50) of 19.53 µg/mL for S. aureus UFPEDA 02; whereas F4 showed higher inhibitory action towards DPPH radical (2,2-diphenyl-1-picryl-hydrazyl-hydrate) [dose able to inhibit 50% of the radical (IC50) = 133 ± 9 µg/mL]. F2 and F4 were then subjected to preparative high-performance liquid chromatography (HPLC) and nuclear magnetic resonance (NMR), resulting in the identification of p-hydroxybenzoic acid and hyperoside as the major compounds in F2 and F4, respectively. Hyperoside and p-hydroxybenzoic acid presented IN50 values of 250 µg/mL and 500 µg/mL against S. aureus UFPEDA 02, respectively. However, the hyperoside had an IN50 of 62.5 µg/mL against S. aureus UFPEDA 705, a clinical isolate with multidrug resistant phenotype. Among the purified compounds, the proanthocyanidins obtained from F2 exhibited the higher antioxidant potentials. Taken together, these results highlight the potential of A. colubrina leaves as an alternative source of biomolecules of interest for the pharmaceutical, food, and cosmetic industries.

Atividade antimicrobiana de produtos obtidos de espécies de Piper (Piperaceae) / Actividad antimicrobiana de productos obtenidos a partir de especies de Piper (Piperaceae) / Antimicrobial activity of products obtained from Piper species (Piperaceae)

Introdução: espécies do gênero Piper são encontradas nas regiões tropicais do globo e possuem inúmeras indicações terapêuticas. Objetivos: avaliar a atividade antimicrobiana de extratos e frações de quatro espécies de Piper, além de dois flavonoides isolados de Piper montealegreanum e determinar a concentração inibitória mínima dos produtos ativos. Métodos: o material vegetal foi coletado em diferentes regiões do estado da Paraíba e na cidade de Belém (Pará) submetido à extração com etanol e partição com solventes em grau crescente de polaridade. Os flavonoides foram isolados por meio de técnicas cromatográficas. A avaliação da atividade antimicrobiana foi realizada pelo método de disco-difusão frente a três espécies bacterianas: Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853 e três espécies fúngicas: Candida albicans ATCC 76645, Candida tropicalis ATCC 13803 e Candida glabrata ATCC 15545. Resultados: quase metade dos produtos testados foi capaz de inibir o crescimento de S. aureus com halos de inibição variando entre 8-16 mm. O extrato etanólico bruto e as frações hexânica e CHCl3 das folhas de P. mollicomum mostraram atividade antibacteriana frente as três linhagens testadas. As frações hexânicas de P. arboreum, de P. caldense e de P. mollicomum apresentaram atividade antifúngica, enfatizando a formação do halo de inibição de 28 mm para a fração de P. mollicomum. Os dois flavonoides isolados de P. montealegreanum não apresentaram atividade antimicrobiana. Conclusões: os resultados preliminares deste estudo sugerem que alguns dos produtos obtidos das espécies de Piper são uma fonte promissora de compostos com atividade antimicrobiana(AU)

Introducción: el género Piper se encuentra en las regiones tropicales del mundo y numerosas indicaciones terapéuticas. Objetivos: evaluar la actividad antimicrobiana de extractos y fracciones de cuatro especies de Piper, además de dos flavonoides aislados de Piper montealegreanum y determinar la concentración inhibitoria mínima de los productos activos. Métodos: el material vegetal fue recolectado en diferentes regiones del estado de Paraíba y en Belém (Pará) y sometido a extracción con etanol y partición com disolventes en grado creciente de polaridad. Los flavonoides fueron aislados por medio de técnicas cromatográficas. La evaluación de la actividad antimicrobiana se realizó por el método de difusión en disco frente a tres especies bacterianas:Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853 y três especies de hongos: Candida albicans ATCC 76645, Candida tropicalis ATCC 13803 y Candida glabrata ATCC 15545. Resultados: casi la mitad de los productos ensayados fueron capaces de inhibir el crecimiento de S. aureus con zonas de inhibición entre 8-16 mm. Los extractos etanolicos crudo y fracciones hexano y CHCl3 de las hojas de P. mollicomum mostraron actividad antibacteriana contra todas las cepas probadas. Las fracciones hexano de P. arboreum, P. caldense y P. mollicomum mostraron actividad antifúngica, con énfasis en la zona de inhibición de 28 mm para la fracción de P. mollicomum. Los dos flavonoides aislados de P. montealegreanum no mostraron actividad antimicrobiana. Conclusiones: los resultados preliminares de este estudio sugieren que algunos de los productos obtenidos de especies de Piper son una fuente prometedora de compuestos con actividad antimicrobiana(AU)

Introduction: The species of the genus Piper are widely found in the tropical regions of the globe and have numerous therapeutic indications. Objective: To evaluate the antimicrobial activity of extracts and fractions of four species of Piper and two flavonoids isolated from Piper montealegreanum and determine the minimum inhibitory concentration of the active products. Methods: The plant material was collected in different regions of the state of Paraíba and in Belém (Pará) and subjected to extraction with ethanol and partition with solvents in increasing degree of polarity. Flavonoids were isolated through chromatographic techniques. The evaluation of antimicrobial activity was performed by disk diffusion method front the three bacterial species: Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853 and three fungi species: Candida albicans ATCC 76645, Candida tropicalis ATCC 13803 and Candida glabrata ATCC 15545. Results: Almost half of the products tested were able to inhibit the growth of S. aureus with inhibition zones between 8-16 mm. The crude ethanolic extract and hexane fractions and CHCl3 of P. mollicomum leaves showed antibacterial activity against all the tested strains. The hexane fractions of P. arboreum, P. caldense and P. mollicomum showed antifungal activity, emphasizing the formation of 28 mm inhibition zone for the fraction of P. mollicomum. The two flavonoids isolated from P. montealegreanum showed no antimicrobial activity. Conclusions: preliminary results suggest that some the products obtained from Piper species are a promising source of compounds with antimicrobial activity(AU)