ABSTRACT
Even today, the majority of the world population uses plant-based products (herbal formulations, decoctions, powders, etc.) to treat diabetes mellitus (DM). But, scientic studies have not established in most of the cases the safety and efcacy of traditionally used plant-based medicines. It is true that varying levels of pharmacological (reverse pharmacological) studies have been carried out on experimental animals to determine their usefulness as anti-DM therapeutic agents. However, these studies are insufcient to a large extent. One of the hindrances in the studies on traditional anti-DM plants and plant-based products is the nonavailability of expertise and appropriate inexpensive animal experimental models and in vitro assay systems in most of the laboratories, particularly, in the developing and underdeveloped countries. Although many animal models and in vitro systems are available, most of the scientic studies on antiDM medicinal plants were carried out using alloxan-induced as well as streptozotocin-induced diabetic rats and mice. Some of the in vivo anti-DM models are overlapping between type 1 and type 2 DM; type 2 DM itself is a heterogeneous disease. In the reverse pharmacological studies on existing herbal drugs and in the development of new plant product-based drugs, evaluation of efcacy in appropriate in vivo animal models may be followed by in vitro mechanism of action studies and, if suitable, clinical studies. Agents that show anti-DM effect in animals are not necessarily effective in humans and vice versa. Similarly, agents that show anti-DM effects in in vitro assays are not necessarily effective in in vivo and vice versa. This could be due to the differences in the absorption, metabolism, and elimination of compounds. Studies on experimental animals and human clinical studies are essential to determine the safety and efcacy of herbal medicines. In vitro assays, by virtue of their more rapid output, lower cost, and need for less material, are ideal means of following the active components during a fractionation and isolation process (Soumyanath and Srijayanta 2005). To facilitate systematic study in this direction, the available important in vivo animal experimental models and in vitro assays and clinical methods are briey described in this chapter with appropriate references for details.
