Terminalia catappa is a plant known for its medicinal values. It is richin tannins and flavonoids. It is checked for the presence of the enzyme, Tyrosine Ammonia Lyase (TAL). It converts tyrosine into p-coumaric acid and eliminates non-oxidative ammonia. The crude enzyme was extracted and assay was done using tyrosine as a substrate and tested for the presence of p-coumaric acid. The absorbance value at 410 nm showed the presence of p-coumaric acid and the presence of TAL in the crude enzyme. The methanol extract of Azadirachta indica (neem) is shown to enhance the activity of TAL enzyme. The dry leaves of Azadirachta indica were extracted by methanol using Soxhlet extractor. The extract was added to the crude enzyme and the increase in activity was observed by assay. The activator-enzyme mixture was then used to study its anti-hyperpigmentation activity by using zebrafish as a model. Dechorionated embryos of zebrafish were used as in-vivo models and incubated with the activator-enzyme mixture. The decrease in pigmentation proved that it can be used as a viable drug against hyperpigmentation.