Chundakkai, Sundakkai, Turkey berry, Thai Berry, Maarang in Marthi, Bhurat in Hindi, has got many medicinal values specially stomach related issues. You can google search for the benefits of this Berry.
I have made various dishes with this, the link shall share in this post.
How to make this pickle. I had a very limited quantity of this, so I prepared a Chutney and Pickle using 50 gms for each recipe.