Minor indole alkaloids of Alstonia macrophylla (original) (raw)
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Monoterpenoid indole alkaloids from Alstonia yunnanensis
Journal of natural …, 2009
Eight new monoterpenoid indole alkaloids, alstoyunines A− H (1− 8), along with 17 known analogues, were isolated from Alstonia yunnanensis. The structures of the new alkaloids were established by means of extensive spectroscopic methods. Alstoyunines C (3), E (5), ...
Unusual indole alkaloid-pyrrole, -pyrone, and -carbamic acid adducts from Alstonia angustifolia
Tetrahedron, 2010
Three unusual natural products, viz., alstopirocine, a macroline alkaloid incorporating a substituted pyrrole moiety, pleiomaltinine, an alkaloidepyrone adduct, and pleiomalicine, an alkaloidecarbamic acid adduct, were isolated from the Malayan Alstonia angustifolia. The alkaloid moiety in alstopirocine was alstomicine while that in pleiomaltinine and pleiomalicine was pleiocarpamine. The structures were determined by spectroscopic methods and in the case of pleiomaltinine, confirmed by X-ray diffraction analysis. Possible biogenetic pathways to these unusual compounds are presented.
Indole alkaloids with antibacterial activity from aqueous fraction of Alstonia scholaris
Tetrahedron, 2015
Eleven new indole alkaloids, alstoniascholarines A-K (1-11), along with one known analogue, were isolated from the aqueous fraction of Alstonia scholaris leaf extract. Their structures were established on the basis of extensive spectroscopic data analysis, chemical transformation and quantum theory. Alkaloid 4 possessed a novel skeleton with a 6/5/6 fused-ring and a six membered-ring, the absolute configuration of which was assigned by quantum theory. Alkaloids 6 and 10 showed the best antibacterial activity against Pseudomonas aeruginosa with a MIC value of 3.13 µg/mL.
2010
A total of 25 alkaloids were isolated from the leaf and stem-bark extracts of Alstonia spatulata, of which five are new alkaloids of the strychnan type (alstolucines A-E, 1-5) and the other, a new alkaloid of the secoangustilobine A type (alstolobine A, 6). The structures of these alkaloids were established using NMR and MS analysis and, in the case of alstolucine B (2), also confirmed by X-ray diffraction analysis. A reinvestigation of the stereochemical assignment of scholaricine (13) by NMR and X-ray analyses indicated that the configuration at C-20 required revision. Alkaloids 1, 2, 6, 7, 9, 10, and 13 reversed multidrug resistance in vincristine-resistant KB cells. Plants of the genus Alstonia (Apocynaceae), which are usually shrubs or trees, are distributed over the tropical parts of Central America, Africa, and Asia, with the center of diversity in the Malesian region. 1-3 About six species occur in Peninsular Malaysia and are mainly found in both the lowland and highland forests, as well as in swampy areas. 1,3 Several species have been reported to be used in the treatment of malaria and dysentery. 4,5 The genus represents a rich source of biologically active indole and bisindole alkaloids. 6-39 In continuation of our studies of the alkaloids of this genus, 9-15,20 in the wider context of our studies of the alkaloids of the Malaysian Apocynaceae, 6,7,40 we report the alkaloidal composition as well as the isolation of new biologically active alkaloids from A. spatulata Bl. There has been no previous phytochemical investigation of this species.
Bisindole alkaloids and secoiridoids from Alstonia macrophylla Wall. ex G. Don
Fitoterapia, 2011
The ethanolic extract from stems of a Thai medicinal plant, Alstonia macrophylla Wall. ex G. Don (Apocynaceae) showed a significant inhibitory effect on acetylcholinesterase (AChE) determined by using Ellman assay. Four compounds i.e., a bisindole alkaloid, macralstonine (1), a new bisindole alkaloid, thungfaine (2), a secoiridoid glycoside, sweroside (3) and a new secoiridoid glycoside, naresuanoside (4) were isolated. Compound 4 showed moderate AChE and butyrylcholinesterase (BChE) inhibitory effects. Interestingly, compound 4 inhibited cell growth on human androgen-sensitive prostate cancer cell line (LNCaP) but no effect on viability of human foreskin fibroblast cells (HF).
ALKALOIDS OF ALSTONIA CORIACEA
alkaloids have been identified from the stem bark of Alstonia coriacea from New Caledonia. They are gentianine, lo-methoxy deplancheine, vincamajine, desmethylquaternine, lo-methoxy-3-epi-a-yohimbine, corialstonine and cabucraline. Corialstonine is a novel member of the little represented quinoline alkaloid series.