Initial Characterization of Crude Extracts from Phyllanthus amarus Schum. and Thonn. and Quassia amara L. Using Normal Phase Thin Layer Chromatography
The extracts of many plants used in traditional medicine contain curative agents that are used in many modern medicines. As part of the quest for potentially valuable plants of medicinal value, the plant species Phyllanthus amarus Schum. and Thonn. and Quassia amara L. were chosen based on ethno-pharmacological knowledge from Suriname, South America. Phyllanthus amarus (whole plant) was collected in the city Paramaribo and in the country, and Quassia amara (wood) was collected in the countryside of Suriname.
The aim of this study was to optimize extraction methods in order to maximize the recovery of secondary metabolites in the crude extracts of P. amarus and Q. amara. This was accomplished by examining the influence of different extraction solvents on the presence of secondary metabolites in the extracts by thin layer chromatography (TLC), determining the most suitable mobile phase for the plant extracts, and determining the most suitable detection method.
Ten grams of each species were extracted (w/v 1:10) with 50% methanol in water, 99% methanol, and 50% methanol in chloroform. Thin layer chromatography (TLC) was used to analyze the compounds in the plant extracts. In order to detect the most compounds, it was necessary to determine the optimal mobile phase (chloroform/methanol 9:1; 95:5; or 98:2) and most suitable detection method (I: UV-254 nm and Phosphomolybdic acid reagent; II: UV-365 nm and Dragendorff reagent; III: ethanolic sulfuric acid reagent; or IV: ethanolic sulfuric acid and UV-365 nm).
For both plant species, crude extracts from methanol and chloroform-methanol yielded the highest number of fractions. Mobile phase chloroform/methanol 95:5 eluted the most fractions and had the best separation. Detection method I detected a wide variety of fractions/compounds. In the P. amarus extracts the following secondary metabolites were visualized: alkaloids, flavonoids, lignans, phenols and indole derivatives. In Q. amara extracts, alkaloids (e.g. ?-carbolines, canthin-6-ones) and quassinoids were detected.
Methanol as an extraction solvent gave the best recovery (extraction rate) of secondary metabolites in both plants, and it can be concluded that different extraction solvents influence the extraction rate. Optimized powder extracts were produced as determined by TLC analysis for future bioassay tests.
Advisor:Cornelis de Hoop; Michael Stine; Isiah Warner; Zhijun Liu
School:Louisiana State University in Shreveport
School Location:USA - Louisiana
Source Type:Master's Thesis
Keywords:forestry wildlife and fisheries
Date of Publication:04/09/2003