ULTRAVIOLET-MEDIATED CYTOTOXIC ACTIVITY OF PHENYLHEPTATRIYNE FROM BIDENS-PILOSA L

The tropical weed Bidens pilosa L. (Asteraceae) contains a number of polyacetvlenes which are phototoxic to bacteria, fungi, and human fibroblast cells in the presence of sunlight, artificial sources of long-wave ultraviolet light, or coolwhite fluorescent light. The principle photoactive compound in the leaf, phenylheptatriyne, is present in the cuticle as well as in the underlying cells. Experiments with calf thymus DNA indicate that, unlike photoactive furanocoumarins, phenylheptatriyne does not form interstrand cross linkages with DNA in ultraviolet light. © 1979, American Chemical Society. All rights reserved.