**7. Bioassay**

At this point of the bioassay with the most active pure compound, the methodology chosen should be definitive and not the whole array of test for the particular disease of interest.

#### **7.1. The experimental model of a disease**

The experimental model of a disease aids not only the understanding of the pathophysiology of the disease but also the development of drugs for its treatment [30]. In the bias of the relaying researcher, the several animal models existing for studying diabetes mellitus (DM) are treated below. And with this knowledge, the reader can deduct relevant idea to use in her/his field of interest. It should be noted that certain disease state may have more than one model for scientific study. And the choice of test may be the use of more than one model which would be sufficient to satisfy the general entity of the pathophysiology of the disease state.

#### *7.1.1 Normoglycemic animal model*

Normal healthy animals are used for testing potential oral hypoglycemic agents. This method allows for the effect of the drug to be tested in the animal with an intact pancreatic activity [30]. This is a valid screening method often used in addition to diabetic animal models [31]. This means that using this model alone would not be sufficient for the study of this disease of interest.

#### *7.1.2 Oral glucose loading animal model*

In this method the animals are fasted overnight, then an oral glucose load (1.0–2.5 g/kg body weight) is given, and blood glucose level is monitored. This method is often referred to as physiological induction of DM because there is no damage to the pancreas even with raised blood glucose level. And in the clinical setting, it is referred to as oral glucose tolerance test (OGTT), used for diagnosis of borderline DM [30].
