STUDIES ON THE PHOTOLYSIS OF PYRETHRUM

The rates of photolysis of films of pyrethrum were studied to determine the factors which could contribute to their increased stability. The claims that the green colouring matter ( referred to as chlorophyll) present in crude oleoresin contributed to the rapid photolysis of pyrethrum films were verified. Evidence was accumulated to show that light of a wide range of wavelengths could effect photolysis. The action of para-aminoazobenzene as a stabilizer was studied in detail and the experimental evidence obtained strongly suggested that this compound did not exert its action by virtue of its light-absorbing properties but as a direct or indirect inhibitor of a chemical reaction. Assays of the four active principles in extract before and after irradiation showed that the PAAB protected primarily the cinerin II and pyrethrin II. Sudan IV and p-methoxyazobenzene and Spirit Red were shown to have similar stabilizing properties to PAAB.