Diphenylamine, an antihyperglycemic agent from onion and tea

Diphenylamine has been isolated as one of the active antihyperglycemic agents of onion. It was identified by ir, uv, cmr, pmr, and mass spectra. It attained the highest percentage in mature onion bulbs; other onion organs contained diphenylamine in lower percentages. Green and black teas were found to contain relatively high percentages of diphenylamine, being higher in the former. Cooking was found to decrease the diphenylamine content.