Globally, the pervasiveness of chronic, non-communicable disease diabetes mellitus is growing by leaps and bounds. It is one of the major causes of premature morbidity and mortality worldwide. Almost 3.2 million people die of diabetes across the world every year. India is one of the major biodiversity centers of the world and enriched by nearly 45,000 plant species. Out of these, about 2,500 species are described in Ayurveda along with over 10,000 formulations. Herbal preparations for various purposes including pharmaceutical and cosmetic form, part of traditional biodiversity uses in India. Even the WHO (World Health Organization) approves the use of plant drugs for different diseases, including diabetes mellitus. Many plants possessing hypoglycemic principles/ properties are known to exist in nature. Some of these are leaves of Gymnema sylvestre, fruits of Withania coagulans and leaves of Ocimum sanctum. Also a large number of polyherbal formulations derived from these plants are presently being prescribed as medicinal/dietary supplements for diabetes mellitus. This paper focuses on pharmacological activity such as serum glucose level, serum total lipids, triglycerides; cholesterol of these plant extract on STZ-Nicotinamide induced diabetic rats for the management of type 2 diabetes and found that G. sylvestre had significantly reduced the serum glucose level in STZ-Nicotinamide diabetic rats while W. coagulans and O. sanctum showed potent hypolipidemic activity in STZ-Nicotinamide rats.