**1.12. Glycosides**

Glycosides are the condensation products of sugars (polysaccharides inclusive) with different varieties of organic hydroxyl (occasionally thiol) compounds. Glycosides are colorless, crystalline water-soluble plant constituents found in the cell sap. Glycosides chemically contain a carbohydrate (glucose) and a noncarbohydrate part (aglycones or genin) [27, 21]. Glycosides can be readily hydrolyzed into its components with mineral acids as they are neutral in reaction and are purely bitter principles commonly found in plants of the family Genitiaceae. The action of the bitters on the gustatory nerves results in increased flow of saliva and gastric juices [27, 21]. Some of the bitter principles due to the presence of tannic acid are either used in restricting flow of blood (as astringents), function in the reduction of thyroxin, and thereby regulate cell metabolism and growth or as antiprotozoal. Examples of glycosides include cardiac glycosides which act on the heart and anthracene glycosides act as purgative and for treatment of skin diseases, while chalcone glycosides are used as anticancer agents [22]. The extracts of plants containing cyanogenetic glycosides have been reported to be useful as flavoring agents in many pharmaceutical formulations. Amygdalin has been used in the treatment of cancer [hydrogen cyanide (HCN) liberated in stomach kills malignant cells] and also as a cough suppressant in various preparations. Intake of cyanogenetic glycosides in excess quantities can be dangerous [22].

**1.17. Steroids**

**1.18. Carotenoids**

functional target.

**2. Conclusion**

are found in large quantities in many plants [44].

*1.18.1. Mechanism of action of phytochemicals*

Plant steroids also known as cardiac or steroid glycosides are one of the most naturally occurring plant phytoconstituents that are applied therapeutically as cardiac drugs or arrow poisons [21]. The cardiac glycosides are majorly steroids having a natural ability to exert specific and powerful action on the cardiac muscle mainly when injected into animal or man. Steroids (anabolic steroids) have the ability to promote nitrogen retention in osteoporosis (a disease following menopause in women causing bones to be porous and subjected to fracture) and in animals with wasting illness [36, 23]. Steroids have the ability to exhibit activities such as antifungal, antiviral, antileukemic, hypnotic, antipyretic, and muscle-relaxant activities and

Phytochemicals—God's Endowment of Curative Power in Plants

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Carotenoids are coloring pigments in plants especially fruits and vegetables; these act as anti-

Phytochemicals may inhibit microorganisms, may interfere with some metabolic processes, or may modulate gene expression and signal transduction pathways [46–48]. Among the many uses, phytochemicals may either be used as chemotherapeutic or chemopreventive agents. Chemoprevention refers to the use of agents to inhibit, reverse, or retard tumorigenesis. In this sense chemopreventive phytochemicals are applicable to cancer therapy, and molecular

The mechanism of action of phytochemicals in general is attributed to proton-motive force disruption, active transport, cytoplasmic membrane disturbance, electron flow, and cell contents' coagulation [51]. There are different modes of action of phytoconstituents which could be anticancer, anti-inflammatory, antioxidant, anti-ulcer, antidiabetic and may be a multi-

God is the creator of all things that are in existence of which plants which are in abundance and of various diversities are among. He put plants in place to serve man especially for food and medicine to heal their diseases. It is therefore imperative to search more into medicinal plants for phytochemicals which can provide a clue in terms of lead (active) compound discovery for the cure of many so-called incurable diseases like cancer, diabetes, hypertension, ulcer, and other degenerative diseases that are just being managed by medical practitioners till the patient passes on. It is realized that many natural remedies carry their cures along with them; therefore, it could be concluded that botanists (plant scientists), pharmacists, pharmacognosists, pharmacologists, chemists, biochemists, and all other fields related to the science of drug discovery should rise up to these challenges of sourcing from plant alternative medi-

cines which God had placed into our hands only left to be discovered.

mechanisms may be common to both chemoprevention and cancer therapy [49, 50].

oxidants to protect the body against the activities of free radicals [45].
