Tenellin and bassianin are deduced from chemical and spectroscopic evidence to be the 3-[(E,E)-4,6-dimethylocta-2,4-dienoyl] and 3-[(E,E,E)-6,8-dimethyldeca-2,4,6-trienoyl] derivatives of 1,4-dihydroxy-5-(p-hydroxyphenyl)-2(1H)-pyridone. Spin–spin coupling information in the 1H and 13C nuclear magnetic resonance spectra after biosynthetic enrichment of tenellin with 13C and 15N isotopes was a valuable aid in elucidating the structure.

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Polyacetylenes and their thiophene derivatives were tested for their effects on human skin. Topically applied alpha-terthienyl evoked bi-phasic phototoxic dermatitis and the appearance of 'sunburn' cells in human epidermis. None of 11 polyacetylenes had the same effect although they mimicked alpha-terthienyl in their phototoxic effects on Candida albicans and certain pathogenic microorganisms. The UV-mediated antibiotic activity of the compounds and their apparent lack of phototoxicity towards the skin suggest a potential topical therapeutic role for them in yeast, fungal and bacterial infections and light-responsive dermatoses. Their topical sensitizing capacity, however, has not yet been studied.

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