Definition: Given an abstract of a paper, generate a title for this paper such that conveys the key focus of the paper.
Input: Abstract: 10 coumarins used in perfumery, cosmetics and ointments, have been investigated by 2 different methods to determine their sensitizing capacity. Only 1 of the compounds, 4-methyl-esculetin, which serves as a sunscreen agent, was found to be a weak sensitizer. All other coumarins were negative. It is assumed that this dihydroxycoumarin becomes a sensitizer when it is enzymically oxidized to the corresponding orthoquinone in the skin.

The sensitizing capacity of coumarins (I).