Curry leaves belong to the citrus fruit family. The curry leaves have a shiny dark green color. Curry leaves are used mostly in South India. Curry leaves have very aromatic leaves and a lemon scent. If you eat the leaves they are bitter and pungent. Curry leaves are sauteed in oil or ghee to release their aroma and flavor. They need to be cooked at high heat. The calming scent of curry leaves is said to alleviate symptoms of stress and anxiety. Curry leaves have a reasonable amount of iron and folic acid. You can store curry leaves in a Ziploc bag in the freezer. Sometimes it can change color but the taste remains the same.
There is a misconception that curry powder comes from curry leaves. Curry leaf is an herb whereas curry powder is a spice mixture of coriander, turmeric, cumin, and cayenne. Curry powder was invented in Britain to flavor Indian Dishes.