Extractives from samadera madagascariensis and toddaliopsis bremekampii.
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This work involves the isolation, structural elucidation and the biological screening of compounds from the Madagascan Samadera madagascariensis and Toddaliopsis bremekampii from South Africa. Samadera madagascariensis Jussieu (locally known as "fatriana") belongs to the Simaroubaceae family and is endemic to Madagascar. The leaves of Samadera madagascariensis are used in Madagascar for the treatment of stomach aches and dysentry, and the juice of the fresh leaves is used to treat wounds and burns. Samadera madagascariensis leaves were investigated in this work for the presence of quassinoids and triterpenoids. Eighteen compounds, including seven quassinoids: samaderine A (i), the novel 5~,6-dihydrosamaderine A (ii), the novel 2chlorosamaderine A (iii), the novel samaderine DN (iv), samaderine B (v), cedronin (vi) and the novel 3,4~-dihydrosamaderine C (vii), and eleven triterpenoids: the novel protosamaderine A (viii), 1,2-dihydrobruceajavanin A (ix), chisocheton compound A (x), the novel protosamaderine B (xi), the novel protosamaderine C (xii), the novel protosamaderine D (xiii), the novel protosamaderine E (xiv), the novel protosamaderine F (xv), the novel protosamaderine G (xvi), the novel protosamaderine H (xvii) and the novel protosamaderine I (xviii) were isolated from the Samadera madagascariensis leaves. The quassinoids isolated in this work are of the C18 and C19 classes, and only five of the C18 type have been published previously. Quassinoids exhibit a range of biological activities such as antileukemic, antiviral, antimalarial, anti-inflammatory, antifeedant and amoebicidal. 2-Chlorosamaderine A (iii), cedronin (vi) and 3,4~-dihydrosamaderine C (vii) were found to have anticarcinogenic properties. The triterpenoids isolated in this work are of the protolimonoid type and protolimonoids are known to exhibit anticarcinogenic and antifungal properties. Toddaliopsis bremekampii I. Verd. belongs to the Rutaceae family. Members of the Toddaliopsis genus are found in the warmer regions of southern Africa. The phytochemistry of this species and genus has not been investigated previously, however, other members of the Rutaceae have yielded a wide range of alkaloids and other compounds. The leaves and branches of Toddaliopsis bremekampii were investigated in this work and yielded four novel acridone alkaloids: 1,2,3trimethoxyacridone (i), 1,2,3-trimethoxy-1 O-acetoxymethylacridone (ii), 1-hydroxy-2,3-dimethoxy10- acetoxymethylacridone (iii) and 1,2,3-trimethoxy-1 O-methoxy methylacridone (iv). Acridone alkaloids are known to have antineoplastic and antitumour properties. These alkaloids were active in the chemiluminescence assay, which showed the suppression of the reactive oxygen species generated by polymorphonuclear leukocytes (PMNs) in humans. The PMNs play a key role in the host's defence. However, the reactive oxygen species generated as a result of this defence mechanism cause tissue damage.