Tang Center Research Topics
Cardiovascular disease, both acute and chronic, is a leading cause of significant mortality and morbidity in the United States, accounting for more than 40% of all deaths. In traditional medicinal systems, cardiovascular diseases such as congestive heart failure, hypertension, angina pectoris, atherosclerosis, and arrhythmia have been effectively treated by herbal medicines. Herbs with antioxidant properties are commonly consumed herbal remedies for cardiovascular health worldwide. There is increasing evidence that U.S. patients with cardiovascular diseases resort to either supplemental or substitutional therapy with herbal medicines. Since the pathogenesis of heart disease involves cellular events mediated by oxidative damage, studying the role of antioxidant herbs in prevention or attenuation of heart disease and the involved mechanisms is extremely important. The active antioxidant components found in botanicals differ structurally, potentially leading to differences in biological activities. Using distinct antioxidant herbs will advance our understanding of whether different antioxidants induce distinct cellular responses.
Anticolorectal Cancer Studies
Colorectal cancer is the second leading cause of cancer related death in the United States, and the second most prevalent cancer worldwide. While advances continue to be made in developing effective treatment strategies for colorectal cancer patients, chemotherapies are still limited by severe adverse effects and dose-limiting toxicity. The drug-related adverse events not only worsen patients’ quality of life, but can also lead to their refusal to continue the potentially curative chemotherapy. Use of botanicals may also decrease chemotherapy-induced side effects. The identification of non-toxic chemo-adjuvants from herbal medicines remains an essential step in advancing the treatment of cancer. The development and identification of herbal medications, which can either enhance chemotherapeutic anti-cancer efficacy, and/or reduce the coincident side effects of these treatments, remain an important avenues of research in medical oncology. In September 2008, the National Center for Complementary and Alternative Medicine (NCCAM) has awarded $6 million to create the Center for Herbal Research on Colorectal Cancer. Researchers at the center will study the anti-tumor effects of different preparations of the herbs American ginseng (Panax quinquefolius), and notoginseng (Panax notoginseng).
Dr. Tong-Chuan He at The Molecular Oncology Laboratory, Department of Surgery, University of Chicago.
Dr. Wei Du at The Ben May Department for Cancer Research, University of Chicago
Chemotherapy-Induced Nausea and Vomiting
Surgery, chemotherapy and radiotherapy form the cornerstones of treatment in cancer. In advanced stages of the disease, the therapy consists mostly of chemotherapy and radiation. Both these modes of therapy are highly cytotoxic, causing a number of severe adverse events. The patients not only bear the biological effects of cancer but also suffer from the adverse effects of therapy. Nausea and vomiting are significant adverse effects of chemotherapeutic agents, experienced by 30-90% of patients. The currently available anti-emetic drugs can relieve the symptoms especially when used in combination, but may lead to additional adverse events related to these drugs, and potential drug-drug interactions that reduce the efficacy of chemotherapy agents. Patients with cancer often resort to complementary and alternative medical means to treat the side effects of chemotherapy. We have been using American ginseng and other medicinal herbs in preventing and treating chemotherapy-induced nausea and vomiting. Ginseng may not only prevent emesis, but may also have other beneficial effects for cancer, such as tumoricidal properties.
Type 2 diabetes is a chronic metabolic disorder characterized by reduced tissue responsiveness to insulin and progressive loss of pancreatic beta-cell function. The resulting hyperglycemia, which is the hallmark of diabetes, leads to several severe complications. Considering the limitations of current pharmacological therapies for type 2 diabetes, such as high secondary failure rates and side effects, the enormous economical burden of treating diabetic complications, and a significant increase in the incidence, we are investigating newer anti-diabetic agents, especially those from botanicals.
Antioxidant Herbal Research
Antioxidants are compounds that protect cells against the damaging effects of reactive oxygen species (ROS). Some ROS, such as superoxide and hydrogen peroxide, are normally produced in cells as by-products of biochemical reactions or as signaling molecules. When ROS-generating reactions are activated excessively, pathological quantities of ROS are released to create an imbalance between antioxidants and ROS. Oxidative stress, which may result in cellular damage, has been linked to cardiovascular disease, diabetes, cancer, and other degenerative conditions. Many herbal medicines possess antioxidant properties. Herbal antioxidants, such as ginseng, grape seed, green tea, and Scutellaria baicalensis, may protect against these diseases by contributing to the total antioxidant defense system of the human body. The activity of these antioxidant herbs to affect various pathological processes mediated by ROS depends on their ability to access the sites or sub-cellular compartments of biochemical activity. If the activity of these botanicals in promoting antioxidant tissue defense can be established using contemporary methods, these herbs may have potential roles in preventing and treating diseases.
Botanical Identification and Analysis
According to the World Health Organization, reports of patients experiencing negative health consequences caused by the use of herbal medicines are on the rise. These cases are usually linked to the incorrect identification of plant species, the poor quality of herbal medicines, and/or inadequate labeling. Thus, botanical identification and analysis are very important issues for the safe and effective use of herbal products. Furthermore, standardization of herbal medicine is currently a topic of global concern. Because of the diversity of sources of botanical materials, many problems must be solved before the target of standardization of herbal medicine is reached. Using advanced analytical techniques, we are improving and developing methods for botanical identification, quantitative determination of their constituents, and herbal extract standardization using bioassay-guided fractionation and active constituent isolation.
Dr. Harry H.S. Fong at The Department of Medicinal Chemistry and Pharmacognosy, University of Illinois at Chicago.