Alkaloids are the natural compounds which mostly contain basic nitrogen atoms. They are characterized by multilateral pharmacological activity, broad spectrum of therapeutic action and hypo-toxicity. The extraction of alkaloids from Carica papaya leaves was realized with organic solvent and the result was justified by thin layer chromatography (TLC) in which a TLC plate coated with silica gel was marked 2cm at two edges, spotted and put in a chromatographic tank with solvent mixture chloroform/methanol (9:1), and was allowed to elute for 1hour. Iodine crystal was used to visualize the spots which gave the R_f values 0.593, 0.360, 0.302, 0.232, 0.174, 0.110. When Dragendroff’s reagent was spread on the plate, the spot with R_f0.360 was the only one seen. From the result, it shows that carpaine (R_f0.360) was detected in the dry leaves of Carica papaya chromatographically.

CHAPTER ONE

1.0 INTRODUCTION

1.1 BACKGROUND OF THE STUDY

Alkaloids are a group of naturally occurring chemical compounds which mostly contain basic nitrogen atoms. This group also includes some related compounds with neutral and even weakly acidic properties (Grant, 2005). Also some synthetic compounds of similar structure are attributed to alkaloids. In addition to carbon, hydrogen and nitrogen, alkaloids may also contain oxygen, sulphur and more rarely other elements such as Chlorine, bromine and phosphorus. The compounds have complex molecular structures and manifest significant pharmacological activities. Alkaloids are produced by a large variety of organisms including bacteria, fungi, plants and animals and are part of the group of natural products (also called secondary metabolites), (Hampel, 2002).

Chemical, pharmacological and botanical properties must all be considered when classifying a compound as an alkaloid. Their basic character may be due to amino group or nitrogen atom in a heterocyclic system. Broadly, they are considered as true alkaloids, proto alkaloids or pseudo alkaloids (Grayson, 2001).

The alkaloid carpaine was first isolated in 1890 from Papaya leaves and was considered the major alkaloids of Carica papaya (Barger et al, 1999). Pseudo Carpaine, a stereoisomer of Carpaine was regarded as the minor alkaloids (Gavindachari, 2004). Two new alkaloids dehydrocarpaine I and dehydrocarpaine II were identified in Papaya leaves as viscous oils (Tang, 1998) also reported that the failure of recognizing the two new alkaloids in the past was attributed to the fact that they do not crystallize readily as carpaine does.

1.2 STATEMENT OF THE PROBLEM

Alkaloids had been reported to have some physiological action on human; many are poisonous. Thus, they are of considerable importance in pharmacology, medicine and toxicology. Hence the need to know the quantity and type of alkaloid present in Carica papaya leaves.

1.3 OBJECTIVES OF THE STUDY

- To extract alkaloids from Carica papaya

- To determine the quantity of alkaloid present in the Carica papaya leaves.

- To recommend to people the need to use Carica papaya leaves as medicine for the treatment of malaria, stroke, as a sliming tea etc.