ABSTRACT
Cancer stands as second most common cause of disease-related deaths in humans. Resistance of cancer to chemotherapy remains challenging to both scientists and physicians. Medicinal plants are known to contribute significantly to a large population of Africa, which is to a very large extent linked to folkloric claims which is part of their livelihood. In this review paper, the potential of naturally occurring anti-cancer agents from African flora has been explored, with suggested modes of action, where such data is available. Literature search revealed plant-derived compounds from African flora showing anti-cancer and/or cytotoxic activities, which have been tested in vitro and in vivo. This corresponds to 400 compounds (from mildly active to very active) covering various compound classes. However, in this part II, we only discussed the three major compound classes which are: flavonoids, alkaloids and terpenoids.
Subject(s)
Alkaloids/pharmacology , Antineoplastic Agents, Phytogenic/pharmacology , Biological Products/pharmacology , Flavonoids/pharmacology , Neoplasms/drug therapy , Plants, Medicinal/chemistry , Terpenes/pharmacology , Alkaloids/chemistry , Alkaloids/isolation & purification , Antineoplastic Agents, Phytogenic/chemistry , Antineoplastic Agents, Phytogenic/isolation & purification , Biological Products/chemistry , Biological Products/isolation & purification , Cell Proliferation/drug effects , Flavonoids/chemistry , Flavonoids/isolation & purification , Humans , Medicine, African Traditional , Molecular Conformation , Neoplasms/pathology , Structure-Activity Relationship , Terpenes/chemistry , Terpenes/isolation & purificationABSTRACT
A new altersolanol derivative, 4-dehydroxyaltersolanol A (9), along with two known sesquiterpenoids, (S)-7'-hydroxyabscisic acid (7) and (S)-abscisic acid (8) were obtained from the endophytic fungus, Nigrospora oryzae, isolated from leaves of Combretum dolichopetalum. The host plant yielded six known compounds including ellagic acid (1), 3, 3', 4-tri-O-methylellagic acid (2), arjunolic acid (3), 4'-dihydrophaseic acid (4), echinulin (5) and arestrictin B (6). Close structural similarities with regard to compounds 4, 7 and 8 were observed between the metabolites from the host plant and those of the endophytic fungus. Furthermore compounds 5 and 6 are related to alkaloids isolated from N. oryzae previously thus stressing the notion that some of the isolated plant metabolites may actually be of fungal origin. The structures of the isolated compounds were established by spectroscopic methods including 1D, 2D NMR, MS, and by comparison with the literature. 4-Dehydroxyaltersolanol A (9) and 3, 3', 4-tri-O-methylellagic acid (2) showed cytotoxicity against L5178Y mouse lymphoma cells with IC50 values of 9.4 and 29.0 µM, respectively.
Subject(s)
Anthraquinones/chemistry , Ascomycota/chemistry , Combretum/chemistry , Animals , Anthraquinones/isolation & purification , Cell Line, Tumor , Combretum/microbiology , Endophytes/chemistry , Mice , Molecular Structure , Plant Leaves/chemistryABSTRACT
Cancer is known to be the second most common disease-related cause of death among humans. In drug discovery programs anti-cancer chemotherapy remains quite challenging due to issues related to resistance. Plants used in traditional medicine are known to contribute significantly within a large proportion of the African population. A survey of the literature has led to the identification of ~400 compounds from African medicinal plants, which have shown anti-cancer, anti-proliferation, anti-tumor and/or cytotoxic activities, tested by in vitro and in vivo assays (from mildly active to very active), mainly alkaloids, terpenoids, flavonoids, coumarins, phenolics, polyacetylates, xanthones, quinones, steroids and lignans. The first part of this review series focuses on xanthones, quinones, steroids, coumarins, phenolics and other compound classes, while part II is focused on alkaloids, terpenoids, flavonoids.
