Phenylalanine is the predominant antisickling agent in Cajanus cajan seed extract.

Amino acid analysis showed that solvent extracts of Cajanus cajan L. Millsp. (Fabaceae) seeds (white species) contain, as free amino acid, as much as 26.3% phenylalanine. Antisickling experiments based on the estimated amount of free phenylalanine in the methanol (water-soluble) extract of the seeds showed that the presence of this amino acid alone could account for about 70% of the antisickling potency of Cajanus cajan seed extract.