Alkaloidal extracts of six selected species of Amaryllidaceae were studied with respect to their antibacterial and anti-yeast activity and their alkaloidal fingerprint. Twenty-five alkaloids were determined by GC/MS, and sixteen of them identified from their mass spectra, retention times and retention indexes. In the antimicrobial assay, Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus were used, along with isolates of the human pathogenic yeasts Candida albicans, C. glabrata, C. dubliniensis and Lodderomyces elongiosporus. The six extracts, together with 19 Amaryllidaceae alkaloids isolated in our laboratory, showed almost no inhibitory activity against the bacteria tested. However, promising anti-yeast properties were detected; the most potent activity was shown by lycorine, which inhibited C. dubliniensis with a MIC of 32 µg/mL, C. albicans and L. elongiosporus, both with MICs of 64 µg/mL, followed by caranine inhibiting C. dubliniensis with a MIC of 128 µg/mL. Among the alkaloidal extracts, Narcissus jonquilla cv. Baby Moon showed the most potent anti-yeast activity, with minimal and average MIC values of 128 and 192 µg/mL, respectively, followed by Leucojum aestivum, Narcissus poeticus var. recurvus and N. canaliculatus (average MICs 256, 267 and 299 µg/mL, respectively). The lowest MIC value among extracts was obtained for N. canaliculatus against L. elongiosporus (MIC 64 µg/mL).
Three new alkaloids, bersavine (3), muraricine (4), and berbostrejdine (8), together with seven
known isoquinoline alkaloids (1–2, 5–7, 9, and 10) were isolated from an alkaloidal extract of the root bark
of Berberis vulgaris. The structures of the isolated
compounds were determined by spectroscopic methods, including 1D and
2D NMR techniques, HRMS, and optical rotation, and by comparison of
the obtained data with those in the literature. The NMR data of berbamine
(5), aromoline (6), and obamegine (7) were completely assigned employing 2D NMR experiments.
Alkaloids isolated in sufficient amounts were evaluated for their
in vitro acetylcholinesterase, butyrylcholinesterase (BuChE), prolyl
oligopeptidase, and glycogen synthase kinase-3β inhibitory activities.
Selected compounds were studied for their ability to permeate through
the blood–brain barrier. Significant human BuChE (hBuChE) inhibitory activity was demonstrated by 6 (IC50 = 0.82 ± 0.10 μM). The in vitro data were further
supported by computational analysis that showed the accommodation
of 6 in the active site of hBuChE.
-Three taxa of the subgenus Sibiricobombus live in the Near-East mountain steppes: Bombus niveatus, B. sulfureus and B. vorticosus. The latter is also present in the Balkan. B. niveatus and B. vorticosus can only be distinguished based on color pattern. B. sulfureus differs in coat color and in genitalia. We identified 40 compounds in the secretions of the labial glands of these taxa, among which 7 were detected for the first time in labial cephalic gland secretions of bumblebee males. Whereas the secretions of the male cephalic labial glands of B. sulfureus are very different from those of B. niveatus and B. vorticosus, we found no significant difference between the latter. We conclude that B. sulfureus is a valid species, whereas B. vorticosus is a mere subspecies of B. niveatus: Bombus niveatus ssp. vorticosus Gerstaecker nov. status. cephalic secretions / Sibiricobombus / Bombus / taxonomic status / chemical composition
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