A bioactive agent is a compound that engages in and influences life phenomena in a small amount. Bioactive agents include vitamins and coenzymes, hormones, antibiotics, neurotransmitters, and cytokines, for example, and exist in a variety of forms, ranging from low molecular weight compounds to peptides/proteins. They mainly act as regulators of biological functions and are also used as pharmaceuticals.
Toxins are substances that cause abnormalities in the homeostasis and physiological functions of an organism through physical or chemical reactions. Toxins are harmful to living organisms, but toxins that inhibit specific chemical reactions contribute to elucidating the mechanism of life phenomena, including inflammatory responses and signaling in an organism.