Studies on Fagara rhoifolia Lam. and Diplorrpynchus condylocarpon Pichon

Part I of this work presents a review of the tertiary and quaternary alkaloids of the genus Fagara, family Rutaceae, comprising a detailed account of the physical data of the alkaloids and a survey of the pharmacological actions of these and related alkaloids. Methods are discussed for the extraction, separation and purification of tertiary and quaternary alkaloids, with particular reference to the screening for alkaloids in plant material. The alkaloidal compositions of three fractions obtained from the bark of Fagara rhoifolia Lam. were studied; fractions I and II were shown to contain similar quaternary alkaloids whilst fraction III was shown to consist of a mixture of one quaternary and five tertiary alkaloids. The two major quaternary alkaloids of fractions I and II were isolated and shown to be 5-hydroxy-2,3,6-trimethoxy-alpha,beta-dimethyl-aporphinim chloride and (-)-methylcanadine chloride. The remaining minor quaternary alkaloids were not isolated as pure compounds. (-)-Methylcanadine chloride was identified as the major alkaloid, and the only quaternary base, of fraction III which also contained allocryptopine, as the principal tertiary base, together with other minor, uncharacterised, tertiary alkaloids. The stem and root barks of four African Fagara species, Fagara leprieurii Engl., F. macrophylla Engl., F. viridis A. Chev. and F. xanthoxyloides Lam., were examined for the presence of tertiary and quaternary bases. A suitable method was devised for the separation of these two groups of bases. The mixtures of tertiary and quaternary alkaloids of the four African Fagara species were compared by means of suitable thin-layer chromatographic systems. The results showed sufficient valuation in the constituent alkaloids to differentiate the four species, but the similarities showed that the four had a close chemical relationship, Although several authors have reported tertiary alkaloids in these African Fagara species, the present work is the first to report the presence of quaternary alkaloids. Part II comprises the results of an alkaloidal screening of some Apocynaceous plant materials and a review of the alkaloidal constituents previously reported in other species of the genera involved in this survey. The presence of alkaloids was demonstrated in extracts from plant material of Ambelania acida Aubl., Diplorrhynchus condylocarpon Pichon, Mandevilla hirsuta Malme, Ochrosia elliptica Labill, Odontadenia nitida Muell., Prostonia quinquangularis Spreng, Tabemaemontana angolensis Stapf and T. pachysiphon Stapf. This is the first report of alkaloidal material in Ambelania acida, Mandevilla hirsuta, Odontadenia nitida and Tabernaemontana angolensis, though alkaloids have previously been reported in the genera Macoubea (in which Pichon includes the genus Ambelania), Mandevilla, Odontadenia and Tabernaemontana. Extracts from Cameraria belizensis Standley and Carissa edulis Vahl were devoid of alkaloid. The alkaloids of the stem berk of Diplorrhynchus condylocarpon Pichon were isolated and three pure alkaloids were identified as the known bases normacusine B, condylocarpine and mossarabine