Nowadays, the pharmacological research is better and faster tha a few years ago, this is the procedure:
In silico is using only computers and software. For example, do the molecular docking. With that we reduce the huge amount of possible drugs.
In vitro is the pass when we use cells and we use the flow cytrometry. Using PMA to produce free radicals measured with fluorescent compount and check if the plant products reduced free radicals because free adicals produce inflamation. For covid-19 Vero 6 cells from kidney of African green monkey are used because produces protein "ACE2" used for the virus to enter the lunk cell.
In vivo is the pass usig animals. Rat hind paw edema. With a plethysmometer we can mesure the exact volume of a paw rat and when we inject a drug in the rat hind paw we can observe that the volume of the paw is proporcional to the inflamation. Always in all of that steps of research we need three groups. First we need 3 groups of composts analyzed by a computer, 3 groups of cells, 3 groups of animals or 3 groups of persons. First we have the group placebo, we give him an innactive product. later we have the positive control, that have a drug that works. And the last group is the research group, with a the compunt to be studied. COVID-19 ferret mode. Ferret are easilly infected with covid-19. Another thing is that we have the clinical trials, where we will study voluntears, healthy voluntears, small groups of patients and big groups. And finally we have we have the pharmacovigilance.