A PHYTOCHEMICAL INVESTIGATION OF SOME PLANTS BELONGING TO FAMILY FABACEAE AND FAMILY APOCYNACEAE.

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 1: 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 1: Phytochemical investigation of Erythrina caffra Thumb. and Erythrina lysistemon Hutch., family Fabaceae

• Phytochemical investigation of Erythrina caf{ra 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, ill and IV) and one 0-flavonoidal glycoside (compound ll) 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-Al 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-Al 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 089• 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-Al 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 Vll and IX. It should not be confused with abrin, highly toxic hemagglutinating compound 094 195>. Compound EC-2, isolated from the chloroform extract of Erythrina caffra stem bark, was identified as 1-0ctacosanol. Compound EC-2 differs from previously isolated fatty alcohols from the genus Erythrina in the carbon chain length < 169>. Fatty alcohols were