The chemical investigation of the total alkaloid extract (TAE) of the stem bark of Araliopsis soyauxii (Rutaceae) afforded an unreported indolopyridoquinazoline (compound 1) along with nine previously known alkaloids 2–10. In addition, six semi-synthetic derivatives 3a–c, 4b, 5a and 6a were prepared by allylation and acetonidation of soyauxinium nitrate (5), edulinine (3), ribalinine (4) and arborinine (6). The structures and spectroscopic data of five of them are reported herein for the first time. The suggested mechanism for the formation of the new N-allylindolopyridoquinazoline 5a is presented. The structures of natural and derived compounds were determined employing extensive NMR and MS techniques. The absolute configuration of stereogenic centers in compounds 2–4 were determined using NOESY technique and confirmed by the single-crystal X-ray diffraction (SC-XRD) technique. The use of SC-XRD further enabled us to carry out a structural revision of soyauxinium chloride recently isolated from the same plant to soyauxinium nitrate (5). The TAE, fractions, compounds 1–7 and 9, and semi-synthetic derivatives 3a–c, 4b, 5a and 6a were evaluated for their cytotoxic activity towards the cervix carcinoma cell line KB-3-1. No significant activity was recorded for most of the compounds except for 9, which showed moderate activity against the tested cancer cell lines.

Plants synthesize and preserve a variety of metabolites known as natural products. Many of them are easily extractable and can be used as starting material or chemical scaffolds for various purposes, especially in drug discovery. Numbers of reports have listed valuable candidates with privilege scaffolds currently in active development as drugs. New compounds with anticancer and antiinfective activities have been discovered recently, some presented these backbones. The present book chapter aims to highlight these findings from plants which can be considered valuable for the development of new drugs against malignant cells and infective diseases. Interest in anti-infective agents is increasing due to the resistance of microorganisms to existing drugs and newly emerging infectious diseases. This resistance is also, nowadays, associated to some forms of cancers. In addition, the value of plants as essential part in the health care pipeline in low- and middle-income countries is under consideration even though these countries are almost all surrounded by a rich and untapped biodiversity. People are always relying on “modern drugs and treatment” which is unfortunately not affordable to all. Therefore, the present compilation of data on plant-derived compounds can inspire the formulation of ameliorated traditional medicines (ATM) against the targeted diseases and the conservation of species.