ALLELOPATHIC EFFECTS OF HERBAL EXTRACTS

By Melanie J. Messina and John M. Zamora

Department of Biology

The use of plants in the treatment of disease is as old as folk medicine. There are over 1500 antimicrobial and cytotoxic chemicals that have been isolated from plants. The purpose of this study was to see if the hot water extracts of several medicinal herbs, chaparral, burdock root, red clover, paud’ arco, periwinkle, noni, garlic, yucca, flax seed, and yellow dock, inhibited the growth of bean sprouts. This assay is used as a screening test for allelopathy as well as for anticancer activity. Most of the herbal extracts inhibited the growth of the bean sprouts. Chapparal, yellow dock, paud’ arco, and yucca were the most inhibitory. To determine what was occurring microscopically, onion root tip squashes were prepared and fixed onto slides. Altered cell morphology and differences in number of mitotic cells were observed in many of the hot water extracts. It appears that there are allelopathic chemicals in many of these medicinal herbs.