Phytochemicals are the bioactive compounds that plants produce, primarily for their own protection. They occur in fruits, vegetables, whole grains, nuts, seeds, and herbs, and more than a thousand have been identified so far. Among the most significant groups are carotenoids, polyphenols, isoprenoids, phytosterols, saponins, dietary fibers, and polysaccharides.
Although their original role is to help plants adapt and survive—defending against pathogens, pests, and environmental stressors—these compounds have important effects in the human body as well. Many exhibit antioxidant, antimicrobial, antiviral, antispasmodic, and antidiarrheal activities. Others have been shown to regulate gene transcription, enhance communication between cells, support immunity, and offer protective effects against chronic diseases, including certain cancers.
Phytochemistry is the discipline dedicated to studying these compounds. Classical systems of taxonomy once relied primarily on plant morphology and anato…
