Study of ethnobotany and phytochemistry of Pavettacrassipes leaves and Calotropis procera bark fromMalawi.

Abstract

This study aims to analyse the phytochemistry of two medicinal plants locally used by herbalists Pavetta crassipes leaves and Calotropis procera bark from Malawi. The specific objectives of the study are: To extract Pavetta crassipes leaves and Calotropis procera bark using 80% methanol and 100% methanol respectively. To isolate compounds using open column and medium pressure liquid chromatography. To elucidate the structures of isolated pure compounds using nuclear magnetic resonance spectral techniques. The research design was an experimental method. The dried Pavetta crassipes leaves (2900g) and Calotropis procera bark (4500g) was extracted with 3L 80% methanol and 100% MeOH respectively, at room temperature after 72 hours. Using various column chromatographical techniques each of the extracts was isolated to get the pure compounds. The isolated pure compounds were elucidated and characterized using Proton Nuclear magnetic Resonance Spectrum (1H NMR), Carbon Nuclear Magnetic Resonance (13C NMR), Heteronuclear Multiple Bond Coherence (HMBC), Heteronuclear Single Quantum Coherence (HSQC), Distortionless Enhancement via Polarization Transfer (DEPT), Nuclear Overhauser Effect Spectroscopy (NOESY) and Correlation Spectroscopy (COSY). The elucidation of pure compounds from Pavetta classipes yielded flavonoid Quercetin-3-O-rutinoside (1), Chlorogenic acid (2) and Methyl chlorogenate (3) and Calotropis procera yielded taraxasteryl acetate (4) and calactin (5).