Anti-tumor Activity of Nuvastatic^TM (C5OSEW5050ESA) of Orthosiphon stamineus and Rosmarinic Acid in an Athymic Nude Mice Model of Breast Cancer

The current treatment strategies for metastatic breast cancer depend on the cancer subtype by palliating symptoms and prolonging life. However, triple-negative breast cancers have no targeted treatment available. Orthosiphon stamineus (O.s) is a traditional folk medicine plant used in South East Asia to treat many diseases. The aim of this study is to evaluate the anti-tumor activity of O.s extract formulation (ID: C5EOSEW5050ESA trademarked as Nuvastatic^TM) and its major component, rosmarinic acid in a breast in vivo tumor xenograft model. Human triple-negative breast cancer cells were transplanted into the mammary fat pad of 20 athymic nude mice. Fourteen days post-injection, mice were randomly assigned to four groups. C5EOSEW5050ESA (200 and 400 mg/kg/day) and rosmarinic acid (32 mg/kg/day) were administered orally. The body weight and tumor size were measured twice a week. Histopathological analyses of tumor tissues were conducted. Tumor necrosis and tumor growth were determined by hematoxylin and eosin staining. A significant reduction in tumor size and growth was found in all treatment groups. No significant difference between C5EOSEW5050ESA at 200 mg/kg and rosmarinic acid in the reduction of tumor size and necrosis. However, a more significant reduction was found in tumor growth and necrosis with 400 mg/kg of C5EOSEW5050ESA treatment as compared to other treatments. These results highlighted the anti-tumor activity of C5EOSEW5050ESA in reducing breast tumor growth in mice compared to the lower dose of C5EOSEW5050ESA and rosmarinic acid. This study provides valuable insights into using C5EOSEW5050ESA as a treatment to target triple-negative breast cancers in vivo.