Banaba Leaf Extract
Banaba leaf extract is derived from the banaba tree (Lagerstroemia speciosa), which grows throughout Asia. The mature leaves are washed and extracted, and the extract is then filtered, concentrated, and spray-dried. It is standardized to contain 1% corosolic acid, usually most concentrated in mature leaves.1 Other active components include gallic acid and ellagic acid.2 Banaba has been traditionally valued in the Philippines as a medicinal herb.
Corosolic acid in Banaba leaf extract may contain antioxidant properties and lower lipid levels in the blood (antihyperlipidemic).2 Corosolic acid may also lower blood sugar levels and thus decrease the risk of type 2 diabetes.2,3 It has been suggested in a preclinical study that gallic and ellagic acid may contain anti-HIV activity.4
Individuals taking diabetic medication should consult a professional before consuming banaba leaf extracts. Corosolic acid in Banaba leaf extract has been seen to lower blood sugar levels within 60 minutes of administration, which might cause glucose levels to be too low if taken with diabetic medication.2
Jayakumar KS, Sajan JS, Aswati Nair R, Padmesh Pillai P, Deepu S, Padmaja R, Agarwal A, Pandurangan AG. Corosolic acid content and SSR markers in Lagerstroemia speciosa (L.) Pers.: a comparative analysis among populations across the Southern Western Ghats of India. Phytochemistry. 2014 Oct;106:94-103. Epub 2014 Aug 1. PubMed PMID: 25092227.
Miura T, Takagi S, Ishida T. Management of Diabetes and Its Complications with Banaba (Lagerstroemia speciosa L.) and Corosolic Acid. Evid Based Complement Alternat Med. 2012;2012:871495. Epub 2012 Oct 2. PubMed PMID: 230820863.
Kouzi SA, Yang S, Nuzum DS, Dirks-Naylor AJ. Natural supplements for improving insulin sensitivity and glucose uptake in skeletal muscle. Front Biosci (Elite Ed). 2015 Jan 1;7:94-106. PubMed PMID: 25553366.
Nutan, Modi M, Goel T, Das T, Malik S, Suri S, Rawat AK, Srivastava SK, Tuli R, Malhotra S, Gupta SK. Ellagic acid & gallic acid from Lagerstroemia speciosa L. inhibit HIV-1 infection through inhibition of HIV-1 protease & reverse transcriptase activity. Indian J Med Res. 2013 Mar;137(3):540-8. PubMed PMID: 23640562