| Structure Identification: |
| Tetrahedron.1957;1(4):328-337. | | Alkaloid studies–XIX: Alkaloids of some Hawaiian Rauwolfia species: The structure of sandwicine and its interconversion with ajmaline and ajmalidine.[Reference: WebLink] |
METHODS AND RESULTS:
The alkaloid composition of the following three Hawaiian Rauwolfia species–R. sandwicensis A.DC., R. degeneri Sherff and R. mauiensis Sheriff–was determined. Aside from the known aklakoids serpentinine, ajmaline, tetraphylline and tetraphyllicine there were encountered trace amounts of two new dihydroindole alkaloids, mauiensine and sandwicensine as well as larger quantities of an isomer of ajmaline, which was named sandwicine (C20H26N2O2). Since sandwicine and ajmaline yield different dihydro derivatives which are convertible by lead tetra-acetate oxidation to a common indole hemi-acetal, sandwicine represents the C-17 epimer of ajmaline.
CONCLUSIONS:
Dihydrosandwicine was found to be identical with tetrahydroAjmalidine, the sodium borohydride reduction product of Ajmalidine, thereby proving that Ajmalidine is 17-dehydroajmaline. | | Joint Malaysia-UK Symposium on Natural Product Chemistry and Drug Discovery. 2014. | | Distribution of indole alkaloids in Indian Rauvolfia species.[Reference: WebLink] |
METHODS AND RESULTS:
The major alkaloid distributed in the Rauvolfia species endemic to India (R. hookeri and R. micrantha) was identified as reserpiline by NMR studies of the compound isolated by column chromatography of the alkaloid extract. Further, reserpiline with Rf value close to reserpine, has been identified as a compound that can interfere in the HPTLC and HPLC estimation of reserpine. Other indole alkaloids ajmalicine, Ajmalidine, ajmaline, alstonine, deserpidine, sarpagine, tetraphylline, vomilinine and yohimbinic acid were identified by LC-Q-ToF-MS studies 3-4. HPTLC profiling using the marker compounds reserpine, reserpiline and ajmalicine showed close resemblance of the Indian endemic species R. hookeri and R. micrantha.
CONCLUSIONS:
This is the first report of the comparative phytochemical profiling of all the Rauvolfia species in India and the fingerprints will be much useful for the herbal drug industries for quality control measures. |
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