L menthone

Pelargonium roseum (Geraniaceae) essential oil (PREO; Geranium; batch no. 92/2) obtained from Barij Essence Pharmaceutical Co. (Iran) was kept in a refrigerator at 4°C away from direct sunlight. Tween 20 (TW), ethanol (ETH), and chemical constituents of PREO (citronellol [cat no. 27470], geraniol [cat no. 163333], linalool [cat no. L2602], L-menthone [cat no. W266701]) were acquired from Sigma-Aldrich Company (Germany). Technical grade of temephos (97.3%, Pestanal ®; Sigma-Aldrich, Riedel-de Haën, Germany) was received from Institute Pasteur du Laos. The bacterial propagation media, such as brain heart infusion (BHI) broth (M210) and BHI agar (M211), were procured from HiMedia Laboratories, Mumbai, India. Volumetric instruments of class A with the highest grade accuracy were used.

Monoterpenes include (R)-camphor (98%), (L)-menthone (97%), (S)-fenchone (98%), (R)-carvone (98%), geraniol (98%), thymol (98%), (1R, 2S, 5R)-menthol (98%), (S)-limonene (96%), and camphene (95%) which were purchased from Sigma-Aldrich (St. Louis, MO, USA). Citronella oil was supplied from El Gomhoria Co. (Alexandria, Egypt). Chemical structures of these monoterpenes and citronella oil are shown in Figures 1 and 2, respectively. All other commercially available solvents and reagents were used without further purification.