Biotechnologically produced secondary plant metabolites for cancer treatment and prevention

Secondary metabolites of higher plants exert numerous effects on tumorigenesis, on tumor cells in vitro, tumors in experimental animals in vivo, interact with anti-cancer drugs, thus affecting positively or negatively their efficacy, and protect normal tissues of the host organism against adverse effects of anti-cancer therapies. The industrial development of pharmaceutical and nutraceutical products based on secondary plant metabolites is limited due to the following: (i) limited availability of their natural sources, (ii) concern about rare extinguishing plants, (iii) unavoidable contamination of plant extracts with environmental pollutants, (iv) seasonal variations in plant harvesting, (v) poor standardization of the final product due to variable conditions for plant growth, and (vi) difficulties of secondary metabolite extraction from the parts of grown plant. There is now steadily growing interest in the biotechnological approach to produce secondary metabolites using plant cell or plant tissue cultures. In the present review, biosynthesis of secondary metabolites and their role(s) in plant physiology will be briefly discussed; the biotechnological approach to active substances production in the plant cell and plant tissue cultures will be described; examples and mechanisms of cancer preventive and anti-cancer action of some biotechnologically produced plant metabolites will be provided; and future perspectives for biotechnologically produced plant-derived substances in the combined protocols for cancer treatment will be suggested.