8-benzylberbine and N-oxide alkaloids from Aristolochia gigantea

From the ethanol extract of Aristolochia gigantea Mart an 8-benzylberbine-type alkaloid and an N-oxide were isolated together with pinitol and sequoyitol. Structural assignments were based on analysis of spectral data, mainly by 2D NMR spectroscopic techniques. (C) 1997 Elsevier B.V. Ltd.

New selective acetylcholinesterase inhibitors designed from natural piperidine alkaloids

Five new piperidine alkaloids were designed from natural (-)-3-O-acetyl-spectaline and (-)-spectaline that were obtained from the flowers of Senna spectabilis (sin. Cassia spectabilis, Leguminosae). Two semi-synthetic analogues (7 and 9) inhibited rat brain acetylcholinesterase, showing IC50 of 7.32 and 15.1 mu M, and were 21 and 9.5 times less potent against rat brain butyrylcholinesterase, respectively. Compound 9 (1 mg/kg, ip) was fully efficacious in reverting scopolamine-induced amnesia in mice. The two active compounds (7 and 9) did not show overt toxic effects at the doses tested in vivo. (c) 2005 Elsevier Ltd. All rights reserved.

Anxiolytic effects of erythrinian alkaloids from Erythrina mulungu

One new erythrinian alkaloid derivative, (+)-11 alpha-hydroxyerythravine (1), and the known (+)-erythravine (2) and (+)-alpha-hydroxyerysotrine (3) were isolated from the flowers of Erythrina mulungu. Their structures were determined by spectroscopic/spectrometric data interpretation of H-1, C-13, and 2D NMR and MS experiments. The relative configuration was established by NOESY analysis, while the conformation adopted by these molecules was evaluated through molecular modeling studies and coupling constants obtained by NMR analysis. Furthermore, the anxiolytic effects of the E. mulungu aqueous alcoholic crude extract and of the purified alkaloids were evaluated using the elevated T-maze test.

Effects of erythrinian alkaloids isolated from Erythrina mulungu (Papilionaceae) in mice submitted to animal models of anxiety

The effects of acute oral administration of erythrinian alkaloids, Le. (+)-alpha-hydroxy-erysotrine, erythravine and (+)-11 alpha-hydroxy-erythravine isolated from the flowers of Erythrina mulungu were investigated in two animal models of anxiety in mice-the light-dark transition model (LDTM) and the elevated plus-maze (EPM). In the LDTM, erythravine (3, 10 mg/kg) and (+)-11 alpha-hydroxy-erythravine (10mg/kg) increased the time spent by the animals in the illuminated compartment and (+)-11 alpha-hydroxy-erythravine (3 mg/kg) increased the number of transitions between compartments of the LDTM, suggesting an anxiolytic-like effect of these erythrinian alkaloids. Nevertheless, the third alkaloid studied, (+)-alpha-hydroxy-erysotrine, did not change any behavioral response with the range of doses used (3-10 mg/kg). Since the oral administration of the crude extract of E. mulungu (EM) (100-400 mg/kg) did not modify the conventional measures of anxiety in the EPM, this animal model was not chosen to evaluate the anxiolytic properties of the isolated alkaloids. These results suggest that the alkaloids erythravine and (+)-11 alpha-hydroxy-erythravine are responsible for the anxiolytic effects of the crude extract of E. mulungu.

Tetrahydroisoquinoline alkaloids and 2-deoxyribonolactones from Aristolochia arcuata

2-Deoxyribonolactones and four tetrahydroisoquinoline alkaloids were isolated from the acetone extract of the leaves of Aristolochia arcuata Mast., together with pinitol, sequoyitol, glycerol, fructose, sucrose, eupomatenoid-7, salsolinol, and 6,7-dihydroxyl,1-dimethyl-1,2,3,4-tetrahydroisoquinoline. Their structures were determined on the basis of spectroscopic methods, mainly using H-1, C-13, N-15, and P-31 NMR. (C) 2003 Elsevier B.V. Ltd. All rights reserved.

Interactions of indole acetic acid with EGF and FSH in the culture of ovine preantral follicles

The mechanisms that regulate the gradual exit of ovarian follicles from the non-growing, primordial pool are very poorly understood. The objective of this study was to evaluate the effects of adding indole acetic acid (IAA), epidermal growth factor (EGF) and follicle stimulating hormone (FSH) to the media for in vitro culture of ovine ovarian fragments and determine their effects on growth activation and viability of preantral follicles. The ovarian cortex was divided into small fragments; one fragment was immediately fixed in Bouin (control). The other fragments were cultured for 2 or 6 days in culture plates with: minimum essential medium (MEM) supplemented with insulin-transferrin-selenium (ITS), pyruvate, glutamine, hypoxantine, bovine serum albumine and antibiotics (MEM+); MEM+ plus IAA (40 ng/mL); MEM+ plus EGF (100 ng/mL); MEM+ plus FSH (100 ng/mL); MEM+ plus IAA + EGF; MEM+ plus IAA + FSH; MEM+ plus EGF + FSH; or MEM+ plus IAA + EGF + FSH. After 2 or 6 days of culture in each treatment, the pieces of ovarian cortex were fixed in Bonin for histological examination. Follicles were classified as primordial or developing (primary and secondary) follicles. Compared to the control, in all media tested, the percentages of primordial follicles were reduced (P < 0.05) and the percentages of developing follicles were increased (P < 0.05) after 2 or 6 days of culture. Furthermore, culture of ovarian cortex for 6 days reduced the percentages of healthy, viable follicles when compared with the control (P < 0.05), except for cultures supplemented with IAA + EGF and EGF + FSH. In conclusion, the addition of IAA and EGF or EGF and FSH to the culture media were the most effective treatments to sustain the health and viability of activated ovine primordial follicles during in vitro culture. (c) 2005 Elsevier B.V. All rights reserved.

BIOACTIVE AND OTHER PIPERIDINE ALKALOIDS FROM CASSIA-LEPTOPHYLLA

Four new piperidine alkaloids, leptophyllin A (4), 3-acetylleptophyllin A (5), leptophyllin B (8), and (-)-spectaline (1), and 3 known piperidine alkaloids, (-)-spectalinine (2), canavaline (3), and iso-6-canavaline (7), were isolated by a bioassay-guided fractionation of a leaf extract of Cassia leptophylla. The alkaloids 1 - 3 were active in a mechanism-based DNA-modifying yeast assay and 2 was moderately active in Vero monkey and Chinese hamster ovary cell cytotoxicity assays.

Bioactive sesquiterpene pyridine alkaloids from Maytenus aquifolium

Two new sesquiterpene evoninate alkaloids, were isolated together with the known compounds syringaresinol and 4'-O-methyl-(-)-epigallocatechin from the root bark of Maytenus aquifolium. The structures of the two alkaloids were elucidated by interpretation of their spectral data, and both exhibited very weak activity in a mechanism-based DNA-modifying yeast assay. (C) 1998 Elsevier B.V. Ltd. All rights reserved.

ALKALOIDS FROM ARISTOLOCHIA-ARCUATA

Phytochemical studies with Aristolochia arcuata led to the isolation of KNO3, fructose, sucrose, sitosterol, calarene, its 2-oxo derivative, and three neolignans. Besides which, two new 13-oxidodibenzo[a, g]-quinolizinium alkaloids were isolated. They present only one oxygenated substituent at rings A and D.

Indolizidine 239Q and quinolizidine 275I. Major alkaloids in two Argentinian bufonid toads (Melanophryniscus)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Bioactive guanidine alkaloids from Pterogyne nitens

Bioactivity-guided fractionation of a methanolic CHCl 3 extract of the leaves of Pterogyne nitens afforded the known guanidine alkaloid pterogynidine [2] and three new guanidine alkaloids, nitensidines A [3], B [4], and C [5], all of which exhibited selective activity towards the DNA repair-deficient yeast mutant RS 321 (IC 12=9.3-20.0 μg/ml); 3,4, and 5 were moderately cytotoxic to CHO Aux B 1 cells (IC 50=8.5-13.0 μg/ml).

Further sesquiterpene pyridine alkaloids from Maytenus aquifolium

Two new sesquiterpene evoninate alkaloids, aquifoliunine E-III and aquifoliunine E-IV, were isolated from the root bark of Maytenus aquifolium. The structures of the new compounds were elucidated on the basis of spectroscopic methods, including ES-MS.

Electrospray ionization mass spectrometry screening of piperidine alkaloids from Senna spectabilis (Fabaceae) extracts: Fast identification of new constituents and co-metabolites

The fragmentation pattern of a homologous series of piperidine alkaloids isolated from S. spectabilis was investigated using electrospray ionization tandem mass spectrometry (ESI-MS/MS). The ESI-MS and ESI-MS/MS analyses of EtOH extracts and fractions from flowers and fruits of S. spectabilis allowed to elucidate the structures of four new compounds. The identification of these co-metabolites, based on the fragmentation patterns of previously isolated compounds, and further confirmed by accurate mass spectrometry defines this technique as a powerful tool to determine the metabolomic profile of species which has pharmacological importance. ©2005 Sociedade Brasileira de Química.