Biosynthesis of Alkaloids Using Plant Cell Cultures

Abstract

With an estimated 7000 individual structures thus far isolated from plant material, alkaloids are the most diverse of all low molecular weight nitrogen containing compounds. The amount of nitrogen immobilized in these structures varies drastically but, for instance, in cell suspension cultures of Berberis stolonifera which produce up to 3 g of protoberberine alkaloids per liter of medium,¹ 15% of the nitrogen supplied in the medium can be found in alkaloids. Plants in general in their natural environment are nitrogen limited; therefore the sacrifice of valuable nitrogen fixed into alkaloids which generally have no apparent turnover but rather are dead end products is justified only by the fact that these metabolites serve important ecochemic functions for the differentiated plant.² The extreme diversity of alkaloids and their use as pharmaceuticals³ and stimulatory agents (i.e., caffeine, nicotine) of considerable commercial value make this group of compounds an interesting subject for studying their formation within the living system. At this stage of development of plant biochemistry, the elucidation of biosynthetic pathways for secondary compounds has become possible.