Neryl acetate

The standard compounds used for the GC analysis were thymol, trans-anethol, (+)-borneol, (−)-borneol, α-terpineol, L-carvone, (R)-(+)-limonene, eucalyptol, farnesol, neryl acetate, (±)-citronellal, citral, γ-terpinene, nerol, α-pinene, p-cymene, (−)-trans-caryophyllene, geraniol, geranyl acetate, carvacrol, eugenol, sabinene hydrate, bornyl acetate, linalyl acetate, myrcene and (±)-camphor and were purchased from Sigma-Aldrich (St. Louis, MO, USA). In addition, 1,1-Diphenyl-2-picryl-hydrazyl-hydrate (DPPH∙) was obtained from Sigma-Aldrich GmbH (Germany). All chemicals and solvents were analytical reagent grade.

Five-year-old tea plants of Camellia sinensis cv. “Shu Cha Zao” grown at the experimental farm of Anhui Agricultural University in Hefei, China, were used in this study. Standards of geranyl diphosphate (GDP), farnesyl diphosphate (FDP), β-myrcene, β-ocimene, linalool, geraniol, α-citral, β-citral, methyl geranate, nerol, D-limonene, trans-linalool oxide (furanoid), neryl acetate, L-terpineol, α-terpinen, geranyl acetone, thymol, (Z)-nerolidol, α-farnesene, β-farnesene, (E)-nerolidol, humulene, α-ionone, β-ionone, (E)-γ-bisabolene, cadinol and caryophyllene were purchased from Sigma-Aldrich (St. Louis, MO, USA).

8-oxogeranial (CAS# 80054-40-6) & 7S-cis-trans nepetalactol (CAS# 109215-55-6) from Toronto Research Chemicals. 7S-cis-trans and 7S-trans-cis nepetalactone were isolated from Nepeta fassinii “Six Hills Giant” (Burncoose Nurseries, Gwennap, UK) and from catnip oil, respectively using flash silica gel chromatography^{41 (link)}. 7S-cis-cis nepetalactone was isolated from Nepeta mussinii “Snowflake” (Burncoose Nurseries, Gwennap, UK) also using using flash silica gel chromatography^{20 (link)}. 8-oxonerol was synthesized^{19 (link)} by hydrolysis of neryl acetate (Sigma-Aldrich) as an initial substrate. To synthesize the dialdehyde (8-oxoneral), 8-oxonerol (25 mmole) was added to a mixture of MnO₂ (175 mmole) in dichloromethane (50 mL) and stirred at room temperature for 16 h. The mixture was filtered through celite, concentrated in vacuo, and 8-oxoneral was purified via silica flash chromatography using a gradient from 0 to 50% EtOAc in hexane. 7R-trans-trans nepetalactone was isolated from N. sibirica (Beth Chatto, Colchester, UK) following the method for N. racemosa in Liblikas, et al.^{34 (link)}.