The Biochemistry, Toxicology, and Uses of the Pharmacologically Active Phytochemicals: Alkaloids, Terpenes, Polyphenols, and Glycosides

The biochemistry, applications, toxic potentials, and uses of alkaloids, terpenes, polyphenols, and glycosides. Traditional medicine is still recognized and accepted as the desired primary health care system in several communities, with over 80% in developing countries and about 60% of the world’s population directly depending on the medicinal plants for their medical treatment and health purposes. Many parts of plants are being used to return abnormalities to normal, prevent illnesses, and/or allay symptoms. These plant parts contain bioactive compounds; terpenes, glycosides, polyphenols, and alkaloids. Alkaloids have pharmaco-logical activities such as antiasthma, anticancer, and antimalarial. Other alkaloids possess stimulant and psychotropic activities, and are widely used as recreational drugs or in entheogenic rituals. Alkaloids can be toxic too. Although alkaloids act on diverse metabolic systems in humans and animals, they almost uniformly induce a bitter taste. The characteristics and number of the structures of phenol in polyphenols underlie the unique chemical, physical, and biological (metabolic, therapeutic, toxic, etc.) properties of specific members of the class; e.g. ellagitannin and tannic acid. Plants often contain complex mixtures of polyphenols. Several polyphenolic extracts, such as from grape seeds, olive pulp, maritime pine bark, or grape skin, are sold as ingredients for functional foods, cosmetics, and dietary supplements. Terpenes have gained public awareness by the growth and education of recreational and medical cannabis. Terpenoids and terpenes are the primary components of the essential oils of most flowery plants. Essential oils are used widely as scents and fragrances in perfumery and in traditional medicine, such as aromatherapy. Similarly, many plant glycosides are used as medicines. Amygdalin and laetrile (a synthetic derivative) were investigated as potential cancer treatment drugs; nevertheless, they are ineffective and dangerous. Pharmacologically active phytochemicals have useful applications and safety concerns.