Development and Optimization of a High Sensitivity LC-MS/MS Method for the Determination of Hesperidin and Naringenin in Rat Plasma: Pharmacokinetic Approach.

The purpose of this study was to develop, optimize, and fully validate a high-sensitivity methodology using UHPLC-MS/MS to simultaneously quantify hesperidin and naringenin in microsamples (100 µL) of murine plasma after intragastric administration of single pure flavonoids and a mixture. The optimization process allowed for high sensitivity with detection limits of approximately picogram order using an electrospray ionization (ESI) source in negative mode and an experiment based on multiple reaction monitoring (MRM). The validation parameters showed excellent linearity and detection limits, with a precision of less than 8% and a recovery of over 90%. This methodology was applied to compare the pharmacokinetic parameters for the administration of hesperidin and naringenin in individual form or in the form of a mixture. The results showed an absence of significant effects (p > 0.05) for Tmax and Cmax; however, the AUC presented significant differences (p < 0.05) for both flavonoids when administered as a mixture, showing an improved absorption ratio for both flavonoids.

Comparative fingerprint analyses of extracts from the root bark of wild Hippocratea excelsa and "Cancerina" by high-performance liquid chromatography.

A simple high-performance liquid chromatography method was developed for the identification and comparison of quinone-methide triterpenes in wild Hippocratea excelsa and "cancerina" to establish the chromatographic profile of these compounds in root bark. The essential chromatographic conditions for this method are based on a gradient system with a reversed-phase column (C18 ) using proportions of water, methanol, and tetrahydrofuran as mobile phases to correctly separate the signals at 254 and 420 nm and compare the signals to those reported in the literature. The chromatograms exhibit good resolution and precision. Statistical analysis showed that the chromatographic profiles of wild H. excelsa and cancerina do not exhibit significant differences (p≥0.05) in their area proportions or relative retention times. The method developed in this study is suitable for the identification of the major chemotaxonomic markers of the Celastraceae family and can be used for quality control of this herbal root bark, which has uses today in Mexican folk medicine.

The tropical brown alga Lobophora variegata: a source of antiprotozoal compounds.

Lobophora variegata, a brown alga collected from the coast of the Yucatan peninsula, Mexico, was studied for antiprotozoal activity against Giardia intestinalis, Entamoeba histolytica and Trichomonas vaginalis. The whole extract showed the highest activity against T. vaginalis, with an IC(50) value of 3.2 microg/mL. For the fractions, the best antiprotozoal activity was found in non-polar fractions. The chloroform fraction of the extract contained a major sulfoquinovosyldiacylglycerol (SQDG), identified as 1-O-palmitoyl-2-O-myristoyl-3-O-(6'''-sulfo-alpha-D-quinovopyranosyl)-glycerol (1), together with small amounts of 1,2-di-O-palmitoyl-3-O-(6'''-sulfo-alpha-D-quinovopyranosyl)-glycerol (2) and a new compound identified as 1-O-palmitoyl-2-O-oleoyl-3-O-(6'''-sulfo-alpha-D-quinovopyranosyl)-glycerol (3). Their structures were elucidated on the basis of chemical and enzymatic hydrolysis and careful analysis of FAB-MS and NMR spectroscopic data. This is the first report on the isolation of SQDGs from L. variegata. The mixture of 1-3 showed good activity against E. histolytica and moderate activity against T. vaginalis with IC(50s) of 3.9 and 8.0 microg/mL, respectively, however, the activity of 1-3 is not as effective as metronidazole. These results afford ground information for the potential use of the whole extract and fractions of this species in protozoal infections.

Two new 24-isopropenyl-lanostanoids from Tillandsia brachycaulos.

The leaves of Tillandsia brachycaulos afforded two novel tetracyclic triterpenoids identified as (24S)-24-isopropenyl-29-nor-5alpha-lanosta-7-en-3beta-ol (1) and (24S)-24-isopropenyl-29-nor-5alpha-lanosta-7-en-3-one (2), in addition to the known isopimaric acid (3) and chlorogenic acid (4). Their structures were elucidated on the basis of spectral analysis, including homo- and heteronuclear correlation NMR experiments (COSY, ROESY, HMQC and HMBC) and by comparison with data in the literature. The antimicrobial and antifungal activities were studied. The compounds did not show significant activity.