Novák Z

Alkaloids from Zephyranthes robusta BAKER and their acetylcholinesterase- and butyrylcholinesterase-inhibitory activity.

The bulbs of Zephyranthes robusta (Amaryllidaceae) have been extensively analyzed for their chemical constituents, resulting in the isolation of 13 alkaloids. The chemical structures of the isolated compounds were elucidated by mass‐spectrometric, and 1D‐ and 2D‐NMR spectroscopic experiments. The complete NMR assignments were achieved for hippeastidine. All isolated alkaloids were evaluated for their erythrocytic acetylcholinesterase and serum butyrylcholinesterase inhibitory activities using the Ellmans method. Significant acetylcholinesterase inhibition activity was exhibited by 8‐O‐demethylmaritidine (IC50(HuAChE) 28.0±0.9 μM).

Fine Needle Aspiration Biopsy of Mixed Medullary-Follicular Thyroid Carcinoma

BACKGROUND Mixed differentiated thyroid carcinomas are rare tumors, difficult to recognize on fine needle aspiration biopsy (FNAB). Most cases are diagnosed only after histologic investigation. CASES The cases entailed two cytologic samples and a thyroidectomy specimen. Two FNAB thyroidectomy specimens from a 60-year-old man presenting with a solitary thyroid nodule (case 1) were investigated. Both cytologic samples were referred as atypical, with a mixture of features indicating a proliferating follicular lesion but also containing some characteristics of medullary carcinoma. The serum calcitonin level was borderline. Surgery was recommended because of a suspicion of malignancy. The diagnosis of mixed medullary follicular carcinoma was established after a complex histologic investigation. The tumor was encapsulated, with partly microfollicular architecture. Immunohistochemistry was positive for both calcitonin and thyreoglobulin. Electron microscopy from the formol-paraffin block found neurosecretory granules in many cells. The patient was well one year after the operation. One FNAB and thyroidectomy specimen from a 47-year-old woman with long-treated lymphoplasmocellular thyroiditis (case 2) was investigated. The tumor in case 2 was diagnosed on FNAB as medullary carcinoma. Only after histologic and immunohistochemical investigation was mixed differentiation proven. CONCLUSION Mixed differentiated thyroid tumors are a diagnostic challenge on fine needle aspiration. Irrespective of their rarity, they can be suspected if combined features are present. FNAB recognition of the medullary component in both cases was of crucial importance. Nevertheless, definitive diagnosis remains a histologic problem due to the necessity for topographic information.

Isoquinoline Alkaloids from Fumaria officinalis L. and Their Biological Activities Related to Alzheimer's Disease

Two new isoquinoline alkaloids, named fumaranine (2) and fumarostrejdine (10), along with 18 known alkaloids were isolated from aerial parts of Fumaria officinalis. The structures of the isolated compounds were elucidated on the basis of spectroscopic analyses and by comparison with literature data. The absolute configuration of the new compound 2 was determined by comparing its circular dichroism spectra with those of known analogs. Compounds isolated in sufficient amounts were evaluated for their acetylcholinesterase, butyrylcholinesterase, prolyl oligopeptidase (POP), and glycogen synthase kinase‐3β inhibitory activities. Parfumidine (8) and sinactine (15) exhibited potent POP inhibition activities (IC50 99±5 and 53±2 μM, resp.).

Fully substituted pyranones via quasi-heterogeneous genuinely ligand-free Migita-Stille coupling of iodoacrylates.

Migita-Stille coupling of (Z)-β-iodoacrylates with (E)-α-stannyl allylic alcohols to furnish 5-alkylidene-4-substituted-5,6-dihydro-2H-pyran-2-ones is efficiently catalyzed by 2% Pd black in DMF, while Pd(PPh3)4 is inactive. Heterogeneous Pd released in solution is most likely responsible for the catalysis. The reaction is applicable to other substrates, without having to resort to ligands, additives, and/or solid support for Pd. The resulting pyranones can be rearranged to fully functionalized pyranones in another single step.