THE EFFECT OF DIFFERENT LIGHT INTENSITIES ON THE GERMINATION AND EARLY GROWTH OF CHRYSOPHYLLUM ALBIDUM SEEDLINGS
CHAPTER ONE
INTRODUCTION
Nutraceuticals are substances that are regarded as food or part of food that provides medical or health benefits, for the prevention and treatment of diseases (De Felice, 1995). They include a broad range of categories such as dietary supplements, functional foods and herbal products (Radhika et al., 2011). The active compounds or phytochemicals in plants, especially fruits, have been associated with numerous health benefits (Lachance and Das, 2007) and are used as ingredients in many nutraceuticals and pharmaceutical products today. Radhika et al., (2011) listed some sources of active ingredients from plants being used in manufacture of nutraceuticals. Medicinal plants are of great importance to the health of individuals and communities with great potentials for pharmaceutical and nutraceutical applications. The medicinal value of these plants lies in some chemical substances that produce a definite physiological action on the human body and these chemical substances are called phytochemicals. These are non- nutritive chemicals that have protective or disease preventive properties. There are at least fourteen classes of secondary metabolites (phytochemicals) from fruits that exert biological activities and can potentially be used to promote human health. These include alkaloids, amines, cyanogenic glycosides, diterpenes, flavonoids, glucosinolates, monoterpenes, non-protein amino acids, phenylpropanes, polyacetylenes, polyketides, sesquiterpenes, tetraterpenes, triterpenes, saponins and steroids (Thompson and Thompson, 2010). Research by Mukherjee et al. (2011) highlighted some chemical compounds from various parts of plants that exhibit potential antioxidant activities, including madecossoside, asiaticoside, catechin, epicatechin, 4-hydroxycinnamic acid, esculetin, curcumin, xanthorrhizol, anthocyanins, diosgenin, gallic acid, ginsenoside, β-carotene and cyanidin-3-glucoside. However, plant extracts can be toxic with excessive lethal constituents such as aristolochic acids, pyrrolizidone alkaloids, benzophenanthrine alkaloids, viscotoxins, saponins, diterpenes, cyanogenetic glycosides and furanocoumarins (Bahorun et al., 2008). These compounds can affect human health since nutraceutical products, unlike pharmaceutical products, are not as well regulated and are commonly consumed without supervision or medical guidance. On the other hand, phenolic compounds from a variety of fruits such as catechin, anthocyanins, quercetin, kaempherol, resvasterol, curcuminoids, genistein, apigenin, carotenoids, carnosic acid, caffeic acid and ferulic acid are known to possess antioxidant activities and a sun-protective effect against UV light-induced damage (Zaid et al., 2009). Fruits are vital to humans. In fact, humans and many animals have become dependent on fruits as a source of food. They account for a substantial fraction of the world’s agricultural output, and some (such as the apple and the pomegranate) have acquired extensive cultural and symbolic meanings (Lewis, 2002). Generally, fruits are high in fiber, water, vitamin C and sugars, although this latter varies widely from traces as in lime, to 61% of the fresh weight of the date (Braide et al., 2012). Regular consumption of fruit is associated with reduced risks of