Journal of Dietary Supplements, 9(3):155–165, 2012 C 2012 by Informa Healthcare USA, Inc. Available online at www.informahealthcare.com/jds DOI: 10.3109/19390211.2012.708713 ORIGINAL ARTICLES Analgesic Effects of a Standardized Bioflavonoid Composition from Scutellaria baicalensis and Acacia catechu Mesfin Yimam, Lidia Brownell, Mandee Hodges, & Qi Jia Unigen Pharmaceuticals Inc., Lacey, Washington, USA ABSTRACT. Anti-inflammatory properties of both baicalin and catechins have been widely reported. However, the reports of analgesic effects of baicalin and catechins are limited. Three commonly used pain-related animal models were employed to evaluate the analgesic activity of UP446, a standardized bioflavonoid composition of baicalin and catechins. Carrageenan-induced paw edema, formalin test, and abdominal constriction assays were used to evaluate antinociceptive activity of 150 mg/kg or 100 mg/kg oral doses of UP446. Ibuprofen was used as a reference compound in each test. Pretreatment of carrageenan-induced hyperalgesic animals with UP446 at 150 mg/kg oral dosage re- duced the hypersensitivity of pain by 39.5%. Similarly, a single dose of UP446, given orally at 100 mg/kg, exhibited 58% and 71.9% inhibition in pain sensitivity compared to vehicle-treated control in writhing and formalin tests, respectively. These findings sug- gest that the standardized anti-inflammatory bioflavonoid composition, UP446, could also be employed to inhibit nociception. KEYWORDS. Acacia catechu, inflammation, pain, Scutellaria baicalensis INTRODUCTION Current use of prescription and over the counter non-steroidal anti-inflammatory drugs (NSAIDs) has been limited due to untoward gastrointestinal and cardiovascular-related side effects. UP446, a standardized bioflavonoid composi- tion with primarily baicalin from the roots of Scutellaria baicalensis (S. baicalen- sis) and (+)-catechin from the heartwoods of Acacia catechu (A. catechu), has been used in both over the counter joint care dietary supplements and a pre- scription medical food. This natural flavonoid composition reduces production of eicosanoids through inhibition of cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), and 5-lipoxygenase (5-LOX) enzymes (Burnett, Jia, Zhao, & Levy, 2007) and also decreases expressions of inducible nitric oxide synthase (iNOS), nuclear Address correspondence to: Mesfin Yimam, DVM, MS, Unigen Pharmaceuticals Inc., 2660 Willamette Drive NE, Lacey, WA 98516, USA (E-mail: myimam@unigen.net). (Received 8 December 2011; accepted 29 June 2012) 155