Guerin, Patrick

2007, Mohottalage, Susantha, Tabacchi, Raffaele, Guerin, Patrick

The essential oil extracted from Piper betle L. leaf using pilot plant steam distillation was tested against the adult housefly, Musca domestica, for insecticidal activity. LC50 values at the end of 24 and 48 h exposure periods were 10.3 and 8.7 mg/dm(3), respectively. Ceylon citronella oil (Cymbopogon nardus) used as a standard showed LC(50)s of 26.5 and 24.2 mg/dm(3) for the same exposure periods. Bioassay-guided fractionation of P. betle leaf oil revealed safrole and eugenol as the active principles against M. domestica, safrole showing LC50 values of 4.8 and 4.7 mg/dm(3), and eugenol 7.3 and 6.2 mg/dm(3) for the 24 and 48 h exposure periods, respectively, while citronellal (synthetic standard) showed equal LC50 values of 14.3 mg/dm(3) for the same exposure periods. Using safrole as the starting compound, eight analogues were prepared to study structure-activity relationships. Among the eight analogues, dihydrosafrole gave almost equal mortality at LC50 4.7 mg/dm(3) as that of the parent compound safrole after 24 and 48 h exposure, but isosafrole was twice as active as safrole, showing LC50 values of 2.3 and 2.2 mg/dm(3) for the 24 and 48 h exposure periods. Our GC-MS studies on Sri Lankan P. betle leaf oil show that it contains safrole (52.7%), allyllpyrocatechol diacetate (15.4%), eugenol (6.4%) and eugenyl acetate (5.8%) as the major components. Here we also present the GC-MS profile of fractions of Sri Lankan P. betle leaf oil. Copyright (c) 2006 John Wiley & Sons, Ltd.

2007, Mohottalage, Susantha, Tabacchi, Raffaele, Guerin, Patrick

The essential oil extracted from Piper betle L. leaf using pilot plant steam distillation was tested against the adult housefly, Musca domestica, for insecticidal activity. LC₅₀ values at the end of 24 and 48 h exposure periods were 10.3 and 8.7 mg/dm³, respectively. Ceylon citronella oil (Cymbopogon nardus) used as a standard showed LC₅₀s of 26.5 and 24.2 mg/dm³ for the same exposure periods. Bioassay-guided fractionation of P. betle leaf oil revealed safrole and eugenol as the active principles against M. domestica, safrole showing LC₅₀ values of 4.8 and 4.7 mg/dm3, and eugenol 7.3 and 6.2 mg/dm³ for the 24 and 48 h exposure periods, respectively, while citronellal (synthetic standard) showed equal LC₅₀ values of 14.3 mg/dm³ for the same exposure periods. Using safrole as the starting compound, eight analogues were prepared to study structure–activity relationships. Among the eight analogues, dihydrosafrole gave almost equal mortality at LC₅₀ 4.7 mg/dm³ as that of the parent compound safrole after 24 and 48 h exposure, but isosafrole was twice as active as safrole, showing LC₅₀ values of 2.3 and 2.2 mg/dm³ for the 24 and 48 h exposure periods. Our GC–MS studies on Sri Lankan P. betle leaf oil show that it contains safrole (52.7%), allylpyrocatechol diacetate (15.4%), eugenol (6.4%) and eugenyl acetate (5.8%) as the major components. Here we also present the GC–MS profile of fractions of Sri Lankan P. betle leaf oil.