Inhibition of tyrosine activity by cultured lichen tissues and bionts.

Axenic, cultured thallus tissues from forty-six species of lichens were evaluated for their inhibitory effect on tyrosinase activity. Methanol extracts of tissues of three lichens, i.e. HYPOGYMNIA PHYSODES, LETHARIA VULPINA, and CETRARIA JUNIPERINA strongly inhibited tyrosinase activity, but extracts from the corresponding natural thalli showed only weak inhibition. The mycobiont of HYPOGYMNIA PHYSODES showed a higher inhibitory action than its photobiont.