SAFETY EVALUATION OF A COMBINATION, DEFINED EXTRACT OF SCUTELLARIA BAICALENSIS AND ACACIA CATECHU

Abstract

A combined extract containing primarily baicalin from Scutellaria baicalensis and (+)‐catechin from Acacia catechu used in both joint supplements and a prescription medical food was tested for safety. Cytotoxicity testing in THP‐1 monocytes showed limited cell death compared to nonsteroidal anti‐inflammatory drugs (NSAIDs). Acute and subchronic toxicity testing demonstrated no abnormalities in any toxicological end points examined including animal body weights, gross organ pathology and tissue histology, and blood chemistries or serology. The extract, when dosed in Fischer 344 rats, a model for gastric toxicity of NSAIDs, showed no evidence of ulceration. No mutagenicity or drug interactions were seen by AMES and cytochrome P450 enzyme inhibition, respectively. When the extract was compared with placebo after administration to a healthy human population, no changes in blood chemistry or serology were observed. Based on these findings, the combined extract with baicalin and catechin appears to possess a safety profile that justifies further testing in humans. PRACTICAL APPLICATIONS A specific ratio of Scutellaria baicalensis and Acacia catechu metabolically balances the inhibition of cyclooxygenase‐1 and cyclooxygenase‐2 (COX‐2) enzymes and provides a comparable amount of 5‐lipoxygenase (5‐LOX) enzyme inhibition in the conversion of arachidonic acid (AA) to inflammatory metabolites. This mechanism of action may yield fewer side effects than traditional nonsteroidal anti‐inflammatory drugs and selective COX‐2 inhibitors produced by their generally specific inhibition of either COX enzyme. Simultaneous inhibition of 5‐LOX may also avoid a “shunt” of arachidonic acid metabolism down the LOX pathway, thus reducing side effects related to excess, unopposed production of inflammatory vasoconstrictive as well as chemoattractive leukotrienes. The net result should be an effective anti‐inflammatory metabolic product for the management of osteoarthritis with an improved toxicity profile and lower requirement for use with gastroprotective therapies.