Biotransformation of Aromatic Aldehydes by Cell Cultures of Peganum harmala L. and Silybum marianum (L.) Gaertn.

Many aldehydes are important components of natural flavours. They are used in food, cosmetic, and biomedical industries in large amounts. Plant cells or microorganisms carry out their production by biotransformation, which is one of the biotechnological methods that allow them to be defined as 'natural'.

Cell cultures of Silybum marianum and Peganum harmala have been studied with a view to investigat their abilities to produce flavonolignans and β-carboline alkaloids respectively. However, we have isolated S. marianum and P. harmala culture strain, which are able to metabolise several aromatic aldehydes. Ten culture strains derived from S. marianum and P. harmala were examined for their ability to biotransform exogenous aromatic aldehyde compounds, including benzaldehyde, 2-methoxybenzaldehyde, 4-methoxybenzaldehyde, cinnamaldehyde and 3-methoxy, 4-hydroxy benzaldehyde. Callus cultures of Silybum marianum and Peganum harmala were established from seedlings, and healthy suspensions were grown using the Murashige and Skoog medium. Exogenous aromatic aldehydes were fed to S. marianum and P. harmala cell suspension cultures. Biotransformation reactions were detected over 24 h of incubation. The cultures then extracted with dichloromethane and extracts subjected to GC and GC-MS analysis. The S. marianum cultured cells in this study exhibit greater selectivity in the reduction of aromatic aldehydes than P. harmala cultured cells. The ability of cultured plant cells to biotransform substrate appears to be dependent on the culture strains as well as the nature and position of the substituent on the aromatic ring.