Narrative review of production of antioxidants and anticancer compounds from Bryophyllum spp. (Kalanchoe) using plant cell tissue culture

Abstract

For centuries, plants have been widely used in traditional medicine worldwide for the treatment of many diseases. The subgenus Bryophyllum (genus Kalanchoe) have been used in ethnobotanic medicine across America, Africa and Asia. Traditionally, some formulations derived from leaves and roots of Bryophyllum spp. have been applied for the treatment of common illness such as coughs, fever, infections, insect bites, wounds and burns. Phenolic compounds and bufadienolides are the two major families of secondary metabolites identified in several species of the subgenus Bryophyllum. These compounds have gained much attention due to their associated antioxidant and cytotoxic activity, but they are synthetized by plants in fairly limited amounts. In this sense, plant tissue culture (PTC) technology provides a powerful methodology, able to overcome the limitations of low yields associated with conventional open field cultivation of medicinal plants. Several types of PTC methods are routinely employed in plant in vitro propagation, although micropropagation and cell culture are the most common. While micropropagation provides a reliable multiplication procedure, enabling a continuous in vitro production of great amounts of whole medicinal plantlets or just their organs producing the bioactive metabolites, such as their leaves and/or roots; the cell suspension culture procedure allows for the massive production of secondary metabolites using huge bioreactors. In both cases, the addition of biotic and abiotic elicitors and metabolic precursors trigger the bioaccumulation of secondary metabolites through the induction of plant defense mechanisms.