Cyclo(-His-Phe)

Catalyst for asymmetric cyanohydrin synthesis. The addition of hydrogen cyanide to benzaldehyde gives the highest optical yield ever obtained for the corresponding cyanohydrin. In a study of McCleland et al., Cyclo(His-Phe) showed significant anti-tumour activity, causing reduction of cell viability in cervical cancer cells. In isolated rat hearts, the diketopiperazine caused a gradual reduction of heart rate and a decrease in coronary flow rate.