Genipa

Genip’s fruit produces a sour, refreshing drink. When immature, it yields an indelible stain. The fruit is eaten as a remedy for jaundice in El Salvador. It is a common practice in Puerto Rico to cut up the fruits, steep them in water until there is a little fermentation, then add flavoring and drink the infusion as a cold remedy. The juice expressed from the leaves is commonly given as a fever reducer in Central America. The pulverized seeds are emetic and caustic. 

The juice of the unripe fruit is colorless but oxidizes on exposure to the air and gradually turns light brown, then blue-black, and finally jet black. It has been commonly employed by South American Indians to paint their faces and bodies for adornment and to repel insects; and to dye clothing, hammocks, utensils and basket materials a bluish-purple. The dye is indelible on the skin for 15 to 20 days.

Because the fruit and its infusion have unusually good keeping quality, Puerto Rican scientists investigated the possible presence of antibiotic principles and proved the existence of antibiotic activity in all parts of the fruit. In 1964, scientists isolated and identified two new antibiotic cyclopentoid monoterpenes, named aptly genipic and genipinic acids.