Abstract
Diabetes mellitus, is a chronic condition with dysregulated glucose levels
and has been affecting a larger global population. The disease, if not controlled, can
lead to several microvascular and macrovascular complications that will impede the
patients' physical and mental well-being in addition to its economic burden. Many
diabetic patients are unaware of the complications and hesitate to take medicines in the
early phase of the disease condition. Furthermore, many patients have limited access to
conventional antidiabetic drugs, which drives the search for newer agents or relying on
alternative/complementary medicines. Ancient systems such as Ayurveda, traditional
African and Chinese medicine, Japanese Kampo medicine, and other systems of
medicine have identified many herbal/plants, and mineral-based agents for treating
diabetes. Many such plants probably more than 800 and their extracts have been
scientifically proven or tested using various experimental models of diabetes in
animals. Despite several In vitro and In vivo studies reporting the effects of extracts of
plants on blood glucose, only a few trials have been performed to validate their efficacy
in treating humans with diabetes. An apparent mismatch in outcomes was observed
while translating the effectiveness of these plants from an experimental animal study to
a human study. These inconsistencies among animal and human studies were
remarkable in some cases. There are several aspects responsible for these variations,
such as variation in plant parts/extracts, dose, duration in different studies, the
difference between animal models and human disease, and initiation of drug treatment
in animal model, which is generally before the induction of diabetes or immediately
after the induction of diabetes. This chapter focuses on the animal studies and human
clinical trials conducted on plant-based extracts and other natural products and the
outcomes in controlling or managing diabetes mellitus.