This book has overviews of the basic principles of isolation, purifcation, structure, and characteristics of natural products isolated from endophytic Streptomyces SUK 25 against methicillin-resistant Staphylococcus aureus (MRSA), bioactivity of compounds, biosynthesis and identifcation of pure compounds, and illustrates current research techniques of structure elucidation. In addition, the DNA microarray, gene expression profles and cytotoxicity of pure compounds were explained in this book.