Biologically active compounds are natural or synthetic substances that have an effect on living organisms. These compounds can influence biological processes, such as metabolism, cell signaling, and immune responses. They are often found in plants, animals, and microorganisms, and can include vitamins, minerals, and phytochemicals. These compounds play a crucial role in health and disease. For example, antioxidants help protect cells from damage, while alkaloids can have medicinal properties. Research into biologically active compounds is important for developing new drugs and understanding how diet and lifestyle choices impact overall health.