Antitermitic and antifungal activities of eugenol and its congeners from the flower buds of Syzgium aromaticum (clove)

Biodegradation of wood by fungi and termites is recognized as one of the most serious problems for wooden structures. In this study, we analyzed the antitermitic and antifungal activities of flower buds essential oil from Syzygium aromaticum and its dominant constituents. Essential oil components were analyzed by gas chromatography and the major compound of essential oil was eugenol (90.6%). The results demonstrated that at the dosage of 50 mu g/g, clove essential oil had 100% mortality to Reticulitermes chinensis after testing for 5 d. Furthermore, we found eugenol killed all termites after testing for 3 d, with an LC50 value of 12.1 mu g/g. Meanwhile, we also found clove essential oil and eugenol displayed activity against three fungi, Trametes hirsuta, Schizphylhls commne, and Pycnoporus sanguineus. We found eugenol was principal antifungal constituent of clove oil. The IC50 values of eugenol against T. hirsuta, S. commne, and P. sanguineus were 83.6, 116.1, and 102.4 mu g/mL, respectively. In addition, comparisons of the termite mortality and antifungal indices of eugenol and its congeners proved that eugenol exhibited the strongest antitermitic and antifungal activities. The clove oil and eugenol have potential for the development of natural wood preservatives. (C) 2015 Elsevier B.V. All rights reserved.