A Review of the Efficacy and Safety of Banaba (Lagerstroemia speciosa L.) and Corosolic Acid

Abstract

Banaba (Lagerstroemia speciosa L.) extracts have been used for many years in folk medicine to treat diabetes, with the first published research study being reported in 1940. This review summarizes the current literature regarding banaba and its constituents. The hypoglycemic effects of banaba have been attributed to both corosolic acid as well as ellagitannins. Studies have been conducted in various animal models, human subjects and in vitro systems using water soluble banaba leaf extracts, corosolic acid-standardized extracts, and purified corosolic acid and ellagitannins. Pure corosolic acid has been reported to decrease blood sugar levels within 60 min in human subjects. Corosolic acid also exhibits antihyperlipidemic, antioxidant, antiinflammatory, antifungal, antiviral, antineoplastic and osteoblastic activities. The beneficial effects of banaba and corosolic acid with respect to various aspects of glucose and lipid metabolism appear to involve multiple mechanisms, including enhanced cellular uptake of glucose, impaired hydrolysis of sucrose and starches, decreased gluconeogenesis and the regulation of lipid metabolism. These effects may be mediated by PPAR, MAP K, NF-κB and other signal transduction factors. No adverse effects have been observed or reported in animal studies or controlled human clinical trials. Banaba extract, corosolic acid and other constituents may be beneficial in addressing the symptoms associated with metabolic syndrome, as well as offering other health benefits.

Management of Diabetes and Its Complications with Banaba (Lagerstroemia speciosaL.) and Corosolic Acid

“…Investigations are needed to clearly define and understand the roles and importance of corosolic acid and related pentacyclic terpene acids relative to the ellagitannins present in Banaba [57]. Finally, additional acute and subchronic animal safety studies are needed.…”

A Review of Natural Stimulant and Non‐stimulant Thermogenic Agents

“…Extracts of Lagerstroemia speciosa (banaba) have been shown to enhance glucose and lipid metabolism in both humans and animals (Stohs et al , 2012a). Corosolic acid is believed to be the primary active agent in banaba with effects being mediated through a variety of signal transduction mechanisms.…”

Corosolic acid inhibits the proliferation of glomerular mesangial cells and protects against diabetic renal damage

“…Corosolic acid (2α-hydroxyursolic acid, CA), a pentacyclic triterpenoid isolated from Lagerstroemia speciosa L7, exhibits anti-tumor8, anti-diabetic9, anti-obesity10, and anti-inflammatory activities11. An increase in cellular uptake of glucose and induction of apoptosis by this compound have been suggested to explain its beneficial effects.…”