Tonkin herbal drug: a multidisciplinary approach to development.

Ipomoea muricata (L.) Jacq, locally known as 'Tonkin', has been used for generations by the Dominicans in the Philippines for medicinal purposes. The seeds, stems and leaves are said to be effective in treating several types of skin ailments such as chronic and gangrenous wounds, cuts and blisters due to burns. Scientific investigations to rationalize the reported medicinal uses of the plant were carried out at University of Santo Tomas. Botanists at the University did the identification and studied the cultivation and propagation of the plant. Pharmacists and chemists worked closely together on the 'Tonkin' seeds. The seeds were found to have both analgesic and antiseptic properties. Chemists identified indolizidine alkaloids in the seeds, to which the analgesic properties have been attributed. Antimicrobial and antifungal compounds were also identified. Different formulations of the crude drug have been made, namely, an ointment for the treatment of skin ailments, glycerol preparation for the treatment of pharyngitis and an otic preparation for the treatment of otitis externa. Limited clinical trials of these formulations were carried out in collaboration with the medical doctors. The clinical trial studies were supported by in vitro studies carried out by microbiologists. Basic research on this plant material is still continuing. Efforts are now underway for the commercial production of the Tonkin ointment.