Isolation of diterpenes from Araucaria sp Brazilian brown propolis and development of a validated high-performance liquid chromatography method for its analysis.

Propolis comprises a complex resinous product composed of plant's parts or exudates, pollen, bee wax, and enzymes. Brazilian brown propolis from Araucaria sp displays several biological activities. Considering the lack of validated analytical methods for its analysis, we are reporting the development of a validated high-performance liquid chromatography with photodiode array detector method to analyze Araucaria brown propolis. The crude propolis were extracted and chromatographed, furnishing six main diterpenes. The isolated standards were used to draw the analytical curves, allowing the studies of selectivity, precision, accuracy, recovery, robustness, the determination of limits of detection and limits of quantification. The mobile phase consisted of 0.1% acetic acid in water and acetonitrile, using an octadecylsilane column, 1 mL/min flow rate and detection at 200 or 241 nm. Relative standard deviation values obtained for intra-day and inter-day precision were lower than 4% for all diterpenes. From the five parameters for robustness, wavelength detection and flow rate were the critical ones. Limits of detection and quantification ranged from 0.808 to 10.359 µg/mL and from 2.448 to 31.392 µg/mL, respectively. The recoveries were between 105.03 and 108.13%, with relative standard deviation values around 5.0%. The developed method is precise, sensitive, and reliable for analyzing Araucaria brown propolis.

Fast and Efficient Method to Obtain Tagitinin F by Photocyclization of Tagitinin C.

There is some evidence in the literature of the photocyclization reaction of Tagitinin C (1) to Tagitinin F (2). Compound 2 has high pharmacological potential, but it is not easy to obtain, while compound 1 is easily obtained from a widespread plant, Tithonia diversifolia. Among different reaction conditions monitored, one was found that allowed the cyclization of 1 into 2 in <15 min in a photo-dependent reaction. Scaling-up the photocyclization of the pure compound 1 into 2 demonstrated 100% yield, and the isolation of 2 from a UV-irradiated extract was eight-fold higher than the quantity isolated from the non-UV-irradiated extract. We were also able to better understand the process of photoconversion and determine methods to isolate and quantify these compounds, which are known for their important antitumoral activities among other important pharmacological properties.

Sclerotinia Sclerotiorum (White Mold): Cytotoxic, Mutagenic, and Antimalarial Effects In Vivo and In Vitro.

This work aimed includes performing the sclerotia chemical profile and evaluates their biological effects on mutagenesis, oxidative stress, cancer, and malaria. A chemical profile was determined by ultraperformance liquid chromatography mass spectrometry (UHPLC-HRMS) analysis dereplicating norditerpenoid dilactone, sclerolide, and other compounds. The GI50 values to cancer cells (19.8 to 277.6 µg/mL) were higher than normal (16.05 µg/mL), meaning high cytotoxicity. Regarding the oxidative stress, the results showed that the all AcOET fraction concentrations tested on IMR90 noncancer cell increased reactive oxygen species (ROS) production in more intense way (by fivefold) than in tested cancer cells. The in vivo study showed an increase of the following biomarkers (by 296.00%): % DNA in comet tail in peripheral blood and liver cells; micronucleated erythrocytes and colon cells and lipid serum peroxidation. These results indicate the sclerotia as genotoxic and mutagenic agent and its contamination may lead to fungal toxic effects with a risk to human health.

Casearin D inhibits ERK phosphorylation and induces downregulation of cyclin D1 in HepG2 cells.

Cancer is a public health problem which represents the second cause of death in the world. In this framework, it is necessary to identify novel compounds with antineoplastic potential. Plants are an important source for discovering novel compounds with pharmacological potential. In this study, we aimed to investigate the antiproliferative potential of isolated compounds from Casearia sylvestris on tumor cell lines. Crude extract effectively reduced cell viability of 4 tumor cell lines (HepG2, A549, U251-MG, and HT-144) after 48h treatment. HepG2 and HT-144 were the most responsive cells. Three fractions (aqueous ethanol, n-hexane and ethyl acetate) were tested against HepG2 and HT-144 cells and we observed that compounds with antiproliferative activity were concentrated in n-hexane and ethyl acetate fractions. The casearins A, G and J were isolated from n-hexane fraction, while casearin D was obtained from ethyl acetate fraction. We demonstrated that casearin D significantly inhibited the clonogenic capacity of HepG2 cells after 24h exposure indicating its antiproliferative activity. In addition, G1/S transition cell cycle arrest in HepG2 cells was also observed. These effects are related, at least in part, to ability of the casearin D in reducing ERK phosphorylation and cyclin D1 expression levels.

Isolation and evaluation of the antioxidant activity of phenolic constituents of the Garcinia brasiliensis epicarp.

A new glycosylated biflavonone, morelloflavone-4'″-O-ß-d-glycosyl, and the known compounds 1,3,6,7-tetrahydroxyxanthone, morelloflavone (fukugetin) and morelloflavone-7″-O-ß-d-glycosyl (fukugeside) were isolated from the epicarp of Garcinia brasiliensis collected in Brazil. The structures of these compounds were established using 1H and 13C NMR, COSY, gHMQC and gHMBC spectroscopy. The compounds exhibited antioxidant activity. The greatest potency was displayed by morelloflavone (2), with IC50=49.5mM against DPPH and absorbance of 0.583 at 400µg/mL for the reduction of Fe3+. The weakest potency was displayed by 1,3,6,7-tetrahydroxyxanthone (1), with IC50=148mM against DPPH and absorbance of 0.194 at 400µg/mL for the reduction of Fe3+.