الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 219 |  |  |
| | | from | 219 | | |
Abstract
The work presented in this thesis is a further contribution to the phytochemical
investigations of three ornamental plants, cultivated in Egypt. The plants examined are
Erythrina caffra Thumb. (flowers and stem bark), Erythrina lysistemon Hutch. (stem bark)
and Nerium oleander L. (fruits).
This thesis includes three parts:
Part I: Phytochemical investigation of Erythrina caffra Thumb. and Erythrina
lysistemon Hutch., family Fabaceae
Part II: Phytochemical investigation of Nerium oleander L., family Apocynaceae
Part III: Biological activities of some fractions and the isolated flavonoids
Part I: Phytochemical investigation of Erythrina caffra Thumb. and
Erythrina lysistemon Hutch., family Fabaceae
Phytochemical investigation of Erythrina caffra Thumb.
Previous work on Erythrina caffra examined the alkaloidal fractions and resulted in the
isolation of eleven alkaloids (171, 173). However, no reports in the literature concerning the
flavonoids of Erythrina caffra were found. The work presented in this thesis resulted in the
isolation and identification of fourteen compounds from Erythrina caffra plant. Twelve of
these compounds were isolated for the first time from Erythrina caffra. Three compounds
of them were isolated from the genus Erythrina for the first time and one is a new
compound (Table 60).
The isolated compounds include three C-flavonoidal glycosides (compound I, III and IV)
and one O-flavonoidal glycoside (compound II) from the alcohol extract of Erythrina
caffra flowers.
from the chloroform extract of the stem bark of Erythrina caffra, three isoflavonoidal
compounds were isolated and identified (EC-4, EC-5 and EC-7).
Four alkaloids (EC-3 and EC-6) and (EC-A1 and EC-A2) were isolated from the
chloroform and the alcohol extracts of Erythrina caffra stem bark, respectively.
Compounds EC-3 (erythraline) and EC-6 (erysodine) were previously isolated from
Erythrina caffra, while compound EC-A2, identified as hypaphorine, was previously
isolated from the genus Erythrina. Compound EC-A1 is a new alkaloid, isolated for the
first time from the nature. It is the l isomer of abrine alkaloid (d-isomer) previously
isolated from Abrus precatorius (189, 191) seeds, (family Fabaceae). Abrine and hypaphorine
are 3-indolyl propionate alkaloids. They are belonging to the class of N-methyl amino acid
derivatives. The N-methyl amino acids derivatives are found to exhibit wide range of
biological effects, including antibiotic, anticancer, antiviral, and immunosuppressive
activities. (219). Hypaphorine induces sleep in mice (200).
Compound EC-A1 is identified as (-) abrine. This is the first report for the isolation of
abrine from Erythrina plants. In Egypt, it was difficult to obtain Erythrina caffra seeds.
However, the examination of the alcohol extract of Erythrina lysistemon seed reveals the
presence of abrine using systems VII and IX. It should not be confused with abrin, highly
toxic hemagglutinating compound (194, 195).
Compound EC-2, isolated from the chloroform extract of Erythrina caffra stem bark, was
identified as 1-Octacosanol. Compound EC-2 differs from previously isolated fatty
alcohols from the genus Erythrina in the carbon chain length (169). Fatty alcohols we