ASPECTS CONCERNING HYDROQUINONE EFFECT ON CELL CULTURES OF ARCTOSTAPHYLOS UVA-URSI, CATHARANTHUS ROSEUS AND DIGITALIS LANATA

The experimental support for hydroquinone (HQ) bioconversion to arbutin consisted of cell cultures of: Arctostaphylos uva-ursi (6AUU cell line), Catharanthus roseus (Cr cell line) and Digitalis lanata (15 and 8HQ cell lines). HQ (6 mM) was added to the culture medium and displayed different effects on the physiological processes we had in view, such as: growth, cell viability and peroxidase activity. These processes varied depending on the species or cell lines, amount of fresh inoculum and duration of contact with HQ. Although cell growth suffered less significant variations, cell viability was strongly inhibited in all cell suspensions after the 6 th day of culture. D. lanata cell lines showed the highest resistance to HQ and the most sensitive cell line proved to be A. uva-ursi. In C. roseus and D. lanata (15 cell line), IEF (isoelectric focusing) revealed a basic isoperoxidase (usually involved in stress response). This basic peroxidase had not been expressed in Digitalis lanata (8HQ cell line), which may explain it is higher resistance to HQ. Isoperoxidases associated with the growth process have been also identified. TLC (thin layer chromathography) revealed that all plant cell cultures biotransformed HQ to arbutin, excepting A. uva-ursi cell line.