Ultraviolet-Mediated Cytotoxic Activity of Phenylheptatriyne From Bidens pilosa L.

Abstract

The tropical weed Bidens pilosa L. (Asteraceae) contains a number of polyacetylenes which are phototoxic to bacteria, fungi, and human fibroblast cells in the presence of sunlight, artificial sources of long-wave ultraviolet light, or cool-white 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.

Coumarins and Caterpillars: A Case for Coevolution

“…The composite host plants Antennaria, Artemisia, Eupatorium, Coreopsis, Bidens, Senecio and Erigeron contain several polyacetylenic substances, notably tridecapentayene, thiophene derivatives such as a-terthienyl, and matricaria ester, with antibiotic and phototoxic properties (Towers et al, 1977). In the case of a-terthienyl and derivatives, phototoxicity to nematodes, fungi and insects depends on the presence of longwave ultraviolet radiation (Gommers and Geerligs, 1973;Wat et al, 1981), as does the phototoxicity of phenylheptatryene (Wat et al, 1979). Wavelengths below 400 nm are necessary for the photoactivation of furanocoumarins in such Agonopterix hosts as Angelica, Cicuta, Heracleum, and Pastinaca in the Umbelliferae, Ptelea and Xanthoxylum in the Rutaceae, and Psoralea in the Leguminosae.…”

Phototoxicity to selected marine and freshwater algae of polyacetylenes from species in the Asteraceae

“…Four types of reaction of Chlorella were observed (i) 8 of the 22 compounds were scored as inactive; (ii) 8 as phototoxic (toxic only in presence of UV); (iii) 2 as antibiotic (toxic in the presence and absence of UV), and (iv) 4 as "+antiw (toxic in the dark with enhanced toxicity in UV). In general, the activity of Chlorella resembles that previously reported for microorganisms, with many compounds displaying the same activity to Clzlorella that they do toward bacteria and fungi Wat et al 1977). 8-Methoxypsoralen (8-MOP), a photosensitizer whose mode of action is understood, was included in the study for comparative purposes.…”

The wild plants used as traditional medicines by indigenous people of Manokwari, West Papua

“…Bidens pilosa has been the subject of recent clinical studies which have supported many of its uses in herbal medicine (Taylor 1998). As early as 1979, scientists demonstrated that specific chemicals found in this species were phototoxic to bacteria and fungi (Wat et al 1979;Arnason et al 1980). Subsequently, Swiss scientists isolated several known phytochemical compounds with anti-microbial and anti-inflammatory properties which led them to believe that the presence of these compounds may rationalize the use of this plant in traditional medicine in the treatment of wounds, against inflammation and against bacterial infection of the gastrointestinal tracts (Geissberger and Sequin 1991).…”