“Know’st thou the land where the lemon-trees bloom,
Where the gold orange glows in the deep thicket’s gloom,
Where a wind ever soft from the blue heaven blows,
And the groves are of laurel and myrtle and rose.”

– Johann von Goethe


Overview

Leaves of the banaba, Lagerstroemia speciosa, also known as Pride of India and crape or crepe myrtle, have been traditionally consumed in Southeast Asia as treatment for diabetes. The tree is native to several tropical countries including India and the Philippines.

What are the known benefits?

Much research documents that banaba lowers blood sugar. In fact, this study deemed the effects of banaba comparable to those of the commonly prescribed drug Metformin – at least in rabbits. For results in humans, look at this overview of several studies.

Any other potential benefits?

Banaba is also believed to lead to weight loss, lower cholesterol, and increase antioxidant activity.

Any reports casting doubt on purported benefits?

This study found no significant change in glucose markers among people taking a cocktail of herbals including banaba. Click on the other links and decide for yourself.

What is the scientific mechanism at play?

It is believed that corosolic acid, a component of Lagerstroemia as well as cranberry and several plants native to Asia, is the main actor in lowering blood sugar. Another report attributes the beneficial effects to compounds called ellagitannins.

Conclusion

Is banaba a natural herbal cure for diabetes, pre-diabetes or metabolic syndrome? The verdict depends on the study. Click here to read reviews and learn more about banaba teas, extracts, powders and supplements.

References

As always, Wikipedia is a good place to start and has a picture of the chemical structure.
https://en.wikipedia.org/wiki/Lagerstroemia_speciosa

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3468018/

http://www.scopemed.org/?mno=36729

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3303547/

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2176148/