Polyvinyl alcohol-based hydrogel sorbent for extraction of parabens in human milk samples by in-tube SPME-LC-UV.

In this work, we developed an in-tube solid-phase microextraction (SPME) device consisting of a fused silica capillary modified with a polyvinyl alcohol (PVOH) hydrogel. Methylparaben, ethylparaben, propylparaben, and butylparaben were determined in human milk samples by using the in-tube SPME device coupled with liquid chromatography with spectrophotometric detection in the ultraviolet region (LC-UV). The inner surface of the fused silica capillary was silanized to allow covalent modification with the PVOH-hydrogel, using glutaraldehyde as cross-linking agent.

Tyrosinase immobilized enzyme reactor: development and evaluation.

Immobilized enzyme reactors of tyrosinase (tyr-IMERs) for use on-line in HPLC system were prepared by different procedures and then compared. The enzyme, obtained from Agaricus bisporus, was immobilized on epoxy-silica which was prepared using different conditions. Enzyme immobilization was conducted by both in situ and in batch techniques.

Preparation of betulinic acid derivatives by chemical and biotransformation methods and determination of cytotoxicity against selected cancer cell lines.

Several novel 2,4-dinitrophenylhydrazone betulinic acid derivatives have been prepared by chemical and biotransformation methods using fungi and carrot cells. Some compounds showed significant cytotoxicity and selectivity against some tumor cell lines. The most active, 3-[(2,4-dinitrophenyl)hydrazono]lup-(20R)-29-oxolupan-28-oic acid, showed IC50 values between 1.

rac-2-[(2-Chloro-phen-yl)(4-chloro-phen-yl)meth-yl]-1,3-dioxolane.

The title compound, C(16)H(14)Cl(2)O(2), is a chiral mitotane derivative that contains a dioxolane ring and crystallizes from methanol as a racemic mixture. It was obtained in high yield from mitotane and ethyl-eneglycol in alkaline medium, followed by neutralization with sulfuric acid and extraction with ethyl acetate. The mol-ecular structure is stabilized by an intra-molecular C- H⋯ O hydrogen bond.

Therapy of adrenocortical cancer: present and future.

Adrenocortical carcinoma is a rare endocrine malignancy with an estimated worldwide incidence of 0.5 - 2 per million/year. This neoplasm is characterized by a high risk of recurrence and a dismal prognosis owing to unsatisfactory overall survival.

HPLC analysis of oxindole alkaloids in Uncaria tomentosa: sample preparation and analysis optimisation by factorial design.

Introduction: Uncaria tomentosa ("cat's claw") is widely used for the treatment of some infectious and inflammatory diseases. Oxindole alkaloids are regarded as the most important components responsible for the biological activities attributed to the plant. Their analysis require efficient sample preparation and suitable reference standards but few are commercially available.

Plant growth regulation activity of steviol and derivatives.

This work describes the preparation of tetracyclic diterpenoids and determination of their plant growth regulator properties. Stevioside (2) was used as starting material and the derivatives 13-hydroxy-ent-kaur-16-en-19-oic acid (steviol, 3), ent-7alpha,13-dihydroxy-kaur-16-en-19-oic acid (4), 13-hydroxy, ent-kaur-16,17-epoxi-19-oic acid (steviol epoxide, 5), 17-hydroxy-16-ketobayeran-19-oic acid (17-hydroxyisosteviol, 6), 17-hydroxy-16-hydroxyiminobayeran-19-oic acid (7), 16-ketobayeran-19-oic acid (isosteviol, 9), 16,17-dihydroxybeyeran-19-oic acid (8), and 16-hydroxyiminobayeran-19-oic acid (isosteviol oxime, 10) were obtained by simple chemical procedures. Another derivative, ent-7alpha,13-dihydroxycaur-15-en-19-oic acid (4), was obtained by biotransformation of steviol (3) by Penicillium citrinum.

Eupafolin: Effect on mitochondrial energetic metabolism.

This study evaluated the effects of flavone eupafolin (6-methoxy 5,7,3',4'-tetrahydroxyflavone), extracted from dry leaves of Eupatorium litoralle. Eupafolin (25-200microM) promoted inhibition of the respiratory rate in state 3, in the presence of glutamate or succinate. During succinate oxidation, it was found that only state 4 respiratory rate was stimulated approximately 30% by eupafolin (100microM) and ADP/O ratio and RCC were reduced with all doses.

Enzymatic modification of stevioside by cell-free extract of Gibberella fujikuroi.

Stevioside is a natural sweetener obtained from the leaves of Stevia rebaudiana. It is a glycoside of steviol and other glycosides of the same aglycone are also found in the plant. Stevioside is usually the major component in commercial products, but it is not the one with the best organoleptic properties.

Biotransformation of betulinic and betulonic acids by fungi.

Betulinic acid (1), a triterpenoid found in many plant species, has attracted attention due to its important pharmacological properties, such as anti-cancer and anti-HIV activities. The closely related, betulonic acid (2) also has similar properties. In order to obtain derivatives potentially useful for detailed pharmacological studies, both compounds were submitted to incubations with selected microorganisms.

Mitotane associated with cisplatin, etoposide, and doxorubicin in advanced childhood adrenocortical carcinoma: mitotane monitoring and tumor regression.

Purpose: To define a mitotane dose for pediatric patients with adrenocortical cancer (ACC) that maintains therapeutic plasma levels (TL) between 14 and 20 microg/mL and to verify its antitumor efficacy in association with 8 cycles of cisplatin, etoposide, and doxorubicin (CED).

Methods: Powdered mitotane was dissolved in a medium chain triglyceride oil and administered to 11 children with ACC (2.4 to 15.

Is the unilateral lesion of the left substantia nigra pars compacta sufficient to induce working memory impairment in rats?

Adult male Wistar rats with a substantia nigra pars compacta (SNc) lesion induced by intranigral administration of 1 micromol 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) were used as a model of early phase Parkinson's disease (PD). This lesion caused a partial depletion of striatal dopamine (DA). The animals were submitted to a spatial working memory version of the water maze task in which they had to find a hidden (submersed) platform using online-maintained information that the platform remains in the same place during four consecutive trials, but that it is moved to another place every training day.

Activity of isosteviol lactone on mitochondrial metabolism.

Isosteviol lactone (LAC), a lactone derivative of the diterpenic acid isosteviol (ISO) was evaluated for its effect on the oxidative metabolism of mitochondria isolated from rat liver. In this model, LAC (1 mM) depressed the phosphorylation efficiency, as shown by the decreased respiratory control coefficient (RCC) and ADP/O ratio. LAC (1 mM) inhibited NADH oxidase (45%), succinate oxidase (34%) and promoted low-level inhibitions on succinate dehydrogenase (13%), succinate-cytochrome c oxide-reductase (23%), cytochrome c oxidase (10%), and NADH dehydrogenase (13%).

Determination of the diterpenoid, kaurenoic acid, in Annona glabra by HPLC.

The isolation of ent-kaur-16-en-19-oic acid (1) from the leaves and bark of Annona glabra and its determination by reversed-phase HPLC with a photodiode array detector is described. The results indicate that 1 accumulates in the bark of the plant with only very low concentrations in the leaves. Levels of 1 varied throughout the year being highest for bark and leaves in the autumn (5.

Gibberellic acid production by solid-state fermentation in coffee husk.

Five strains of Gibberella fujikuroi and one of Fusarium moniliforme were screened for the production of gibberellic acid (GA3) in coffee husk, and based on the results, one strain, G. fujikuroi LPB-06, was selected. The comparative production of GA3 by solid-state fermentation and submerged fermentation indicated better productivity with the former technique, mainly with pretreated substrate.

Amino acid and monoamine alterations in the cerebral cortex and hippocampus of mice submitted to ricinine-induced seizures.

The alkaloid ricinine isolated from the plant Ricinus communis, when administered to mice at high doses, induces clonic seizures accompanied by electroencephalographic alterations in the cerebral cortex and hippocampus. The lethal nature of ricinine-induced seizures is considered to be a good model for the study of the events that cause death during clonic seizures, particularly those related to respiratory spasms. The initial signs (pre-seizure period) were marked by exophthalmus and decreased locomotor behavior.

Determination of the triterpenoid, betulinic acid, in Doliocarpus schottianus by HPLC.

The isolation, detection and quantification of betulinic acid in Doliocarpus schottianus are described. The isolation from the plant extract was made by column chromatography and centrifugal TLC, and betulinic acid was characterized by spectrometric methods. The detection and quantification were made by HPLC using a C18 column eluted with acetonitrile: water and detected at 210 nm.