A review of nemorosone: Chemistry and biological properties.

Nemorosone is a bicyclic polyprenylated acylphloroglucinol derivative originally isolated from Clusia spp. and it can be obtained through chemical synthesis employing different synthetic strategies. Since its discovery, it has attracted great attention both from a biological and chemical viewpoint. In the present article, we attempted to review various chemical and biological topics around nemorosone, with an emphasis on its antiproliferative activities. For this purpose, relevant data was collected from different scientific databases including Google Scholar, PubMed, Scopus and ISI Web of Knowledge. This natural compound has shown activity against several types of malignancies such as leukemia, human colorectal, pancreatic, and breast cancer because it modulates multiple molecular pathways. Nemorosone has both cytostatic and cytotoxic activity and it also seems to induce apoptosis and ferroptosis. Additionally, it has antimicrobial capabilities against Gram-positive bacteria and parasites belonging to genus Leishmania. Its promising antiproliferative pre-clinical effects deserve further attention for anticancer and anti-parasitic drug development and translation to the clinic.

Chemical characterization and antioxidant potential of ecuadorian propolis.

The chemical composition and the antioxidant potential of Ecuadorian propolis samples (n = 19) collected in different provinces were investigated. HPLC-DAD-ESI/MSn and GC-EI-MS analysis of the methanol extracts enabled us to define six types of Ecuadorian propolis based on their secondary metabolite composition. 68 compounds were identified, 59 of which are reported for the first time in Ecuadorian propolis. The detected compounds include flavonoids, diterpenes, triterpenes, organic acid derivatives, alkylresorcinol derivatives and nemorosone. Plants belonging to genera Populus, Mangifera and Clusia seemed to be vegetable sources employed by bees to produce Ecuadorian propolis. Total phenolic content and antioxidant activity of propolis extracts were determined by the Folin-Ciocalteu assay and 2,2-diphenyl-1-picrylhydrazyl and ferric reducing/antioxidant potential assays, respectively. As expected, the variable chemical composition affected the differences in terms of antioxidant potential.

Microencapsulación mediante secado por atomización a partir de un extracto de los cálices de Hibiscus sabdariffa L / Microencapsulation by spray drying from an extract of the calyces of Hibiscus sabdariffa L / Microencapsulação por secagem por pulverização a partir de um extrato dos cálices de Hibiscus sabdariffa L

Resumen La investigación tuvo como objetivo definir las mejores condiciones de extracción asistida por ultrasonido de los cálices de H. sabdariffa L. y la obtención de polvos microencapsulados, mediante secado por aspersión. Los extractos fueron analizados, considerando como variables: disolvente (agua y agua/etanol) y la relación temperatura/tiempo de extracción (25 °C/60 min y 60 °C/30 min). Para el secado se evaluaron las variables temperatura de entrada (150 °C; 190 °C) y la mezcla de encapsulantes goma arábiga (G) y maltodextrina (MD) (G40/ MD60; G60/MD40). Los parámetros utilizados para el análisis fueron: rendimiento, pH, °Bx, composición química (fenoles y antocianinas totales, CLAE-EM) y capacidad antioxidante (DPPH). La mejor condición para la extracción de polifenoles resultó ser con agua:etanol (80:20), a 60 °C y durante 30 min. Se identificó la presencia de ácidos fenólicos, glicósidos de flavonoles y las antocianinas (delfinidina-3-sambubiósido y cianidina-3-sambubiósido), como las señales de mayor intensidad. Con el secado por atomización a 150°Cy con G60/MD40, se logró el mayor contenido de fenoles totales y antocianinas, sin embargo, la capacidad antioxidante se favoreció a 150 °C y con G40/MD60. Las micropartículas obtenidas podrían valorarse como materia prima para la elaboración de fitofármacos o alimentos funcionales, considerando su fácil manipulación, posible estabilidad y su valor antioxidante.

Abstract The objective of the research was to define the best conditions for ultrasound-assisted extraction of H. sabdariffa L. calyces, and to obtain microencapsulated powders, by spray drying. The extracts were analyzed, considering as variables: extracting solvent (water and water/ethanol) and the temperature /extraction time ratio (25 °C/ 60 min and 60 °C/30 min). Inlet air temperature (150 °C; 190 °C) and the mixture of gum arabic (G) and maltodextrin (MD) as encapsulating agents (G40/MD60; G60/MD40) were the variables studied. The parameters used for the analysis were: yield, pH, °Bx, chemical composition (phenols and total anthocyanins, HPLC-MS), and antioxidant capacity (DPPH). The best polyphenols extraction conditions were water:ethanol (80:20), at 60 °C for 30 min. The presence of phenolic acids, flavonol glycosides, and anthocyanins (delphinidin-3-sambubioside and cyanidin-3-sambubioside) were identified as the signals of highest intensity. Inlet air temperature at 150 °C and G60/MD40 allowed the highest total phenols and anthocyanins content. However, the antioxidant capacity was better at 150 °C and G40/MD60. The microparticle obtained could be used as an ingredient for the preparation of phytopharmaceuticals or functional foods, considering their easy handling, and antioxidant capacity.

Resumo O objetivo da pesquisa foi definir as melhores condições para a extração assistida por ultrassom de H. sabdariffa L. calyces e obter pós microencapsulados, por meio de secagem por pulverização. Os extratos foram analisados considerando-se variáveis: menstruação (água e água/etanol) e a razão temperatura/tempo de extração (25 °C/60 min e 60°C/30 min). Para a secagem, os variais foram avaliados: temperatura de entrada (150 °C; 190 °C) e mistura dos encapsulantes goma arábica (G) e maltodextrina (MD) (G40/ MD60; G60/MD40). Os parâmetros utilizados para a análise foram: rendimento, pH, °Bx, composição química (fenóis e antocianinas totais, HPLC-MS) e capacidade antioxidante (DPPH). A melhor condição de extração acabou com a água: etanol (80:20), a 60 °C e por 30 min. A presença de ácidos fenólicos, flavonol glicosídeos e antocianinas (delfinidin-3-sambubiosídeo e cianidin-3-sambubiosídeo) foram identificados como sinais de maior intensidade. Com a secagem por pulverização a 150°Ce com G60/MD40, foi atingido o maior teor de fenóis e antocianinas totais, no entanto, a capacidade antioxidante foi favorecida a 150 °C e com G40/MD60. As microcápsulas obtidas podem ser utilizadas como matéria-prima na preparação de fitofarmacêuticos ou alimentos funcionais, considerando seu fácil manuseio, possível estabilidade e seu valor antioxidante.

Nigerian propolis: chemical composition, antioxidant activity and α-amylase and α-glucosidase inhibition.

Propolis is an attractive natural ingredient to design health products due to its pharmacological effects. Our chemical investigation of a polar extract of Nigerian propolis (NP) led the isolation and identification of five isoflavonoids (1-4, 6), one diarylpropane (5) and one prenylated flavanone (7) by the combination of chromatographic and spectroscopic techniques. Compounds 1, 4 and 7 were found to be the main markers in NP (8.0, 5.0 and 4.0 mg/g of dry extract, respectively). Moreover, NP and its phenolic constituents exhibited in vitro free radical scavenging activity together with a promising antidiabetic effect against α-amylase and α-glucosidase enzymes. Finally, NP showed also a moderate inhibition of Helicobacter pylori growth. These results suggested that NP could be a good candidate in nutraceuticals and food products.

Cuban Brown Propolis Interferes in the Crosstalk between Colorectal Cancer Cells and M2 Macrophages.

Tumor-associated macrophages (TAMs), primarily the M2 phenotype, are involved in the progression and metastasis of colorectal cancer (CRC). Cuban brown propolis (Cp) and its main component Nemorosone (Nem) displays an antiproliferative effect on different cancer cells, including CRC cell lines. However, whether Cp and Nem could exploit its effect on CRC cells by targeting their relationship with TAMs remains to be elucidated. In this study, we differentiated the human monocytic THP-1 cells to M2 macrophages and confirmed this transition by immunofluorescence (IF) staining, qRT-PCR and zymography. An MTT assay was performed to determine the effect of Cp and Nem on the viability of CRC HT-29 cells co-cultured with M2 macrophages. Furthermore, the migration and invasion abilities of HT-29 cells were determined by Transwell assays and the expression levels of epithelial-mesenchymal transition (EMT) markers were analyzed by IF staining. We demonstrated that Cp and Nem reduced the viability of M2 macrophages and, accordingly, the activity of the MMP-9 metalloprotein. Moreover, we demonstrated that M2 macrophages produce soluble factors that positively regulate HT-29 cell growth, migration and invasion. These M2-mediated effects were counteracted by Cp and Nem treatments, which also played a role in regulating the expression of the EMT markers E-cadherin and vimentin. Taken together, our results indicate that Nem contained in Cp interferes in the crosstalk between CRC cells and TAMs, by targeting M2 macrophages.

The Cuban Propolis Component Nemorosone Inhibits Proliferation and Metastatic Properties of Human Colorectal Cancer Cells.

The majority of deaths related to colorectal cancer (CRC) are associated with the metastatic process. Alternative therapeutic strategies, such as traditional folk remedies, deserve attention for their potential ability to attenuate the invasiveness of CRC cells. The aim of this study is to investigate the biological activity of brown Cuban propolis (CP) and its main component nemorosone (NEM) and to describe the molecular mechanism(s) by which they inhibit proliferation and metastatic potential of 2 CRC cell lines, i.e., HT-29 and LoVo. Our results show that CP and NEM significantly decreased cell viability and inhibited clonogenic capacity of CRC cells in a dose and time-dependent manner, by arresting the cell cycle in the G0/G1 phase and inducing apoptosis. Furthermore, CP and NEM downregulated BCL2 gene expression and upregulated the expression of the proapoptotic genes TP53 and BAX, with a consequent activation of caspase 3/7. They also attenuated cell migration and invasion by inhibiting MMP9 activity, increasing E-cadherin and decreasing ß-catenin and vimentin expression, proteins involved in the epithelial-mesenchymal transition (EMT). In conclusion NEM, besides displaying antiproliferative activity on CRC cells, is able to decrease their metastatic potential by modulating EMT-related molecules. These finding provide new insight about the mechanism(s) of the antitumoral properties of CP, due to NEM content.

Nemorosone inhibits the proliferation and migration of hepatocellular carcinoma cells.

AIMS: In the tumor microenvironment, dysregulated immune cells could promote tumor progression, invasion and metastasis, by establishing a symbiotic relationship with cancer cells. A pivotal role is played by monocyte recruitment and induction of tumor-associated macrophages (TAMs), which provide immunosuppression and tumorigenesis. The effect of nemorosone, an antiproliferative phytocomponent present in Cuban Propolis, on TAM-induced tumor progression remains to be elucidated. Here we investigated the symbiotic relationship between monocytic leukemia THP-1 and hepatocellular carcinoma HepG2 cells, and the role of nemorosone in preventing TAM-induced tumor growth. MAIN METHODS: Macrophage differentiation induced by HepG2-conditioned medium was assessed by flow cytometry, analysis of secreted molecules and cytokine expression. The effect of nemorosone and/or conditioned THP-1-medium on HepG2 proliferation was evaluated by MTT assay, colony formation, cells cycle and migration assays. KEY FINDINGS: HepG2 cells induced THP-1 recruitment and differentiation to macrophages. When compared with control THP-1 cells, differentiated THP-1 showed a significant increase of the matrix metalloproteinases MMP-2 and MMP-9 expression (P < 0.01), and slightly induced HepG2 cells growth. This effect was counteracted by nemorosone, which also significantly inhibited colony formation (P < 0.01) and migratory capacity of HepG2 cells, driving a high percentage of cells (80%) to the G0/G1 phase. SIGNIFICANCE: HepG2-conditioned medium is a suitable model for THP-1 modulation and differentiation. Moreover, nemorosone significantly inhibits the proliferation of HepG2 cells, both in presence and absence of the soluble factors secreted by TAMs. Further studies are needed to elucidate the role of this natural compound in the HCC-TAM relationship.

Chemosensitizing activity of Cuban propolis and nemorosone in doxorubicin resistant human colon carcinoma cells.

Propolis is a natural product obtained from bees, used since ancient times for its multiple pharmacological properties. Several evidences indicate that the antiproliferative effect of propolis against different cancer cell lines can be ascribed to its components. However, little is known about the possible use of this natural product in the treatment of chemo-resistant tumors. Combination experiments were carried out in order to study the ability of Cuban propolis extracts (CP) and its main component (nemorosone) to chemosensitize doxorubicin-resistant human colon carcinoma cells (LoVo Dox) compared to the sensitive cells (LoVo). Antiproliferative effect was determined by MTT assay after 24, 48 and 72 h exposure. Synergistic, additive or antagonistic effects of different combined treatments (CP-Dox and nemorosone-Dox), was evaluated by isobologram-combination index method. The interaction mechanisms between CP or nemorosone with doxorubicin were studied by flow cytometry to investigate cell death pathway and cell cycle arrest. Reactive oxygen species production (ROS) and mitochondrial membrane potential (ΔΨm) modification were also evaluated. Data showed that both CP and its main component nemorosone were able to reduce cell proliferation in a concentration- and time-dependent manner. Combined treatments induced a cell growth inhibition with a significantly synergistic antiproliferative and cytotoxic effect. Co-treatments induced also cell cycle arrest which results in apoptosis by a marked ROS production and drastic alteration of ΔΨm. In summary, our findings evidence the potential role of Cuban propolis extracts and their main component nemorosone as new chemosensitizing agents against drug-resistant human colon carcinoma cells.

Efficacy of Four Solanum spp. Extracts in an Animal Model of Cutaneous Leishmaniasis.

Background: Leishmaniasis is a complex protozoa disease caused by Leishmania genus (Trypanosomatidae family). Currently, there have been renewed interests worldwide in plants as pharmaceutical agents. In this study, the in vivo efficacy of Solanum spp. is assessed in an L. amazonensis BALB/c mice model for experimental cutaneous leishmaniasis. Methods: Animals were infected with 5 × 106 metacyclic promastigotes and 30-day post-infection, a treatment with 30 mg/kg of Solanum extracts or Glucantime® (GTM) was applied intralesionally every four days to complete 5 doses. Results: Neither death nor loss of weight higher than 10% was observed. All the tested extracts were able to control the infection, compared with the infected and untreated group. Solanum havanense Jacq. extract showed the highest efficacy and was superior (p < 0.05) to GTM. Solanum myriacanthum Dunal., S. nudum Dunal. and S. seaforthianum Andr. extracts demonstrated a similar effect (p > 0.05) to GTM. An increase of IFN-γ (p < 0.05) was displayed only by animals treated with S. nudum compared to the group treated with a vehicle, while no differences (p > 0.05) were observed for IL-12. Conclusions:In vivo effects of Solanum extracts were demonstrated, suggesting that this genus could be further explored as a new antileishmanial alternative.

Chemical profile and anti-leishmanial activity of three Ecuadorian propolis samples from Quito, Guayaquil and Cotacachi regions.

Three propolis samples were collected from different regions of Ecuador (Quito, Guayaquil and Cotacachi) and their methanolic extracts were prepared. Preliminary information supplied by TLC and NMR data, allowed us to define two main types of propolis: Cotacachi propoli sample (CPS), rich in flavonoids and Quito and Guayaquil samples (QPS and GPS) containing triterpenic alcohols and acetyl triterpenes as the main constituents. Two different approaches based on RP-HPLC preparative procedure and NMR structural determination (CPS) and GC-MS analysis (QPS and GPS) were successfully used for the chemical characterization of their major compounds. All three propolis extracts were able to inhibit Leishmania amazonensis growth but propolis sample rich in flavonoids was the most active (IC50=17.1±1.7µg/mL). In the literature this is the first study on propolis from Ecuador.