Banaba leaf, also known as Lagerstroemia, is a plant traditionally used in India and the Philippines to treat high blood sugar and diabetes, with the first research paper being published in 1940. However, do banaba leaves work? A 2012 study published in the Evidence-based Complementary and Alternative Medicine journal confirmed that animal and human studies, as well as in-vitro models, show that banaba has an anti-diabetic and anti-obesity effect due to two compounds present in it, corosolic acid and ellagitannins. Other compounds like oleanic acid and valonein acid in the plant may help exert an anti-hyperglycemic effect. 
Benefits of Banaba Leaf
The most active ingredient in these powerful leaves is corosolic acid. This chemical has many benefits, so these leaves are consequently used for a multitude of ailments.
- Corosolic acid is a naturally occurring compound, in banaba leaves, that has been reported to give the body a powerful antioxidant boost, making it potentially useful in the prevention of cervical cancer.  
- Banaba leaf extract is anti-viral, anti-bacterial, and anti-inflammatory. It aids in the treatment of urinary tract infections, liver diseases, and viral diseases.
- Banaba is an anti-diabetic due to the ability of corosolic acid to significantly lower glucose levels. 
- A rat study published in the Journal of Nutritional Science and Vitaminology showed that the leaf had an anti-obesity effect because it helped reduce blood triglycerides.