INTRODUCTION AND LITERATURE REVIEW

1.1 INTRODUCTION

Knowledge of the chemical constituents of plants is desirable, not only for the discovery of therapeutic agents, but also because such information could be valuable in disclosing new sources of economic and important materials as tannins, oils, gums, and precursors for the synthesis of complex chemical substances. Furthermore, the knowledge of the chemical constituents of plants is valuable in discovering the actual value of folkloric remedies (Mojab et al., 2003). Plants have a limitless ability to synthesize substances mainly secondary metabolites, of which at least 12,000 are known, This figure is estimated to be less than10% of the total (Mallikharjuna et al., 2007). The natural substances are used by plants as defensive molecules against microorganisms, insects and herbivores. However, some of these product are involved in determination of plant odour (terpenoids), pigmentation (tannins and quinines), and flavour (Capsacin) (Mallikharjuna et al., 2007). However, these defensive molecules give plants their medicinal value which is exploited by human beings because of their great importance in health care of individuals and communities. These natural compounds formed the basis of modern drugs development today (Edeoga et al., 2005).

1.2 LITERATURE REVIEW

1.2.1 Botany of Mentha Spicata

Spearmint (botanic name Mentha spicata) belongs to the mint family (Lamiaceae) and is indigenous to most of the European regions as well as places in southwest Asia. The species derives its name from the resemblance of the tips of its leaves to pointed lances or spears. However, as spearmint has been extensively cultivated since ancient times. Spearmint is a herb-like rhizomatous (a flat, subversive steam that often sends out roots and shoots from its nodes) plant that thrives best in damp soil conditions. This is a perennial herb that grows up to a height of 30 to 100 cm. The spearmint plant is extremely invasive in nature and was first noticed in the Great Lakes way back in 1843. (Ditomaso and Healy, 2007).The stems of the spearmint plant may or may not have hair-like bristles. The plant has dense undergrowth and an extensive fleshy rhizome beneath the ground. The deep…