Alkaloids of picralima nitida used for treatment of protozoal diseases

A method of preparing substantially purified alkaloids from seeds, fruit-rind and stem-bark of a plant selected from the group consisting of Picralima nitida, Gongronema latifolia, Dorstenia multiradiata, Cola attiensis, Rothmania withfieldii and Desmodium gangeticum, for use in the treatment of drug resistant strains of protozoal diseases, comprising:

• pulverizing said seeds, fruit-rind and stem-bark;
• extracting said pulverized seeds, fruit-rind and stem-bark with a first solvent selected from the group consisting of dichloromethane, methanol, petroleum ether and water, drying the extracted material and re-extracting the dried material with a different solvent than said first solvent, wherein said different solvent than said first solvent is selected from a member of the group consisting of said first solvent;
• extracting a fresh sample of said seeds, fruit-rind and stem-bark with boiling water;
• filtering and concentrating the boiled water solvent extracts under reduced pressure to dryness;
• concentrating the dried extract to a gum and re-extracting said gum with an aqueous acidic HCl solution;
• filtering the acidic extract and making it alkaline to a pH of about 9 with a concentrated NaOH solution;
• extracting the alkaline solution with dichloromethane;
• concentrating organic layers of the extracts of alkaline solution to dryness under reduced pressure to obtain an alkaloid fraction;
• and
• separating the alkaloid fraction by liquid chromotography-mass spectrometry to obtain substantially purified alkaloids for use in treatment of protozoal diseases.