The rind of the mangosteen has a hight tannin content and is used to cure leather in Asia. It is also used to fix the color black in textile dyeing.
The mangosteen (Garcinia mangostana) is a fruit tree native to Malaysia with small, dark reddish brown to purple fruit with a smooth, thick rind, 5 or so seeds.
The flavor is described variously as that of peach and pineapple, strawberry and grape, peach and apple, etc. The juicy flesh, divided into sections like an orange, almost melts in your mouth. Many say the mangosteen is the most delicious fruit in the world. It is usually found only in local markets because it must ripen on the tree, and they only keep a short time.
Mangosteens are not related to the mango.