Bioactive natural products are those chemical compounds produced by living organisms that exert a biological effect on other organisms. All over the world at present scientists investigate plants, microorganisms, marine creatures and many other forms of life for biological activity. The area where activity has been greatest is the effect of extracts from the flowering plants on human physiology and human pathogens, since this is very relevant to the discovery of new drugs for treating diseases of human beings and other mammals. Testing large number of extracts or compounds to determine if they produce a biochemical or cellular effect is usually one of the first steps in the discovery of bioactive compounds.Plants contain a wide variety of antioxidant molecules, such as flavonoids, anthocyanins,carotenoids,etc. Plant antimicrobials may be of great help in dealing with drug-resistant bacteria due to their unique structures which are quite different than those of conventional antibiotics of microbial origin. This work will be of interest to microbiologists, phytochemists, and those who are into natural product chemistry.