Invited Review

No matter how unwilling, it is impossible to run away from aging. And when human ages, metabolism will start to slow down and production of many essential things in the body will be lesser and could not be replenished anymore. One of it is collagen fibers; an insoluble protein which is the major constituent of connective tissues, skin, tendons, cartilage and bones. The function of collagen is to maintain the structural integrity and the mechanical properties of tissues and organs.