In this task, you are given a sentence. You are expected to recognize the name of any form of chemical substances. Although there might be several correct answers, you need to write one of them.

Studies on the antioxidant potential of flavones of Allium vineale isolated from its water-soluble fraction.
flavones

On the relationship between the dopamine transporter and the reinforcing effects of local anesthetics in rhesus monkeys: practical and theoretical concerns.
dopamine

Vitamin A and retinoid signaling: genomic and non-genomic effects.

retinoid