title: The effects of different night-time temperatures and cultivation durations on the polyphenolic contents of lettuce: Application of principal component analysis.
abstract: The present study was conducted to characterize the polyphenolic contents of lettuce leaves grown under different night-time temperatures (4, 12, and 20 °C) and cultivation durations (5, 15, and 20 days) using high performance liquid chromatography-tandem mass spectrometry (LC/MS/MS). The assay method was validated based on specificity, linearity, accuracy, precision, and the performance limit. The total polyphenolic contents were highest (2462.6 mg/kg) after transplantation at a night temperature of 20 °C on day 20 and lowest (1132.7 mg/kg) at the same temperature on day 5. Quantification and principal component analysis showed that the relative contents of quercetin and kaempferol were markedly higher during the early stage of cultivation (day 5) than those of day 15 and 20, and that night-time temperatures of 12 and 20 °C on day 20 were favorable for producing polyphenol-rich lettuce containing caffeic acid. In conclusion, a synergistic effect between high night-time temperatures (12 and 20 °C) and cultivation duration (20 days) produced lettuce rich in polyphenols compared to that at low temperature (4 °C).
authors.affiliation: Department of Chemistry and Research Institute of Life Science, Gyeongsang National University, Jinju 660-701, Republic of Korea.
authors.forename: Sung Woo
authors.initials: SW
authors.lastname: Jeong
authors.affiliation: Research Institute of Life Science and College of Veterinary Medicine, Gyeongsang National University, Jinju 660-701, Republic of Korea.
authors.forename: Gon-Sup
authors.initials: GS
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Institute of Health Sciences, Gyeongsang National University, Jinju 660-701, Republic of Korea.
authors.forename: Won Sup
authors.initials: WS
authors.lastname: Lee
authors.affiliation: Department of Chemistry and Research Institute of Life Science, Gyeongsang National University, Jinju 660-701, Republic of Korea.
authors.forename: Yun-Hi
authors.initials: YH
authors.lastname: Kim
authors.affiliation: Department of Horticulture and Research Institute of Life Science, Gyeongsang National University, Jinju 660-701, Republic of Korea.
authors.forename: Nam Jun
authors.initials: NJ
authors.lastname: Kang
authors.affiliation: Korea Basic Science Institute Busan Centre, Division of High Technology Materials Research, Gangseo-gu, Busan 618-230, Republic of Korea.
authors.forename: Jong Sung
authors.initials: JS
authors.lastname: Jin
authors.affiliation: Department of Information Statistics, Research Institute of Natural Science, Gyeongsang National University, Jinju 660-701, Republic of Korea.
authors.forename: Gye Min
authors.initials: GM
authors.lastname: Lee
authors.affiliation: Department of Information Statistics, Research Institute of Natural Science, Gyeongsang National University, Jinju 660-701, Republic of Korea.
authors.forename: Soo Taek
authors.initials: ST
authors.lastname: Kim
authors.affiliation: Biotechnology Research Institute, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 500-757, Republic of Korea ; Department of Pharmacology, Faculty of Veterinary Medicine, Cairo University, 12211 Giza, Egypt ; Department of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Konkuk University, Seoul 143-701, Republic of Korea.
authors.forename: A M
authors.initials: AM
authors.lastname: Abd El-Aty
authors.affiliation: Biotechnology Research Institute, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 500-757, Republic of Korea.
authors.forename: Jae-Han
authors.initials: JH
authors.lastname: Shim
authors.affiliation: Department of Chemistry and Research Institute of Life Science, Gyeongsang National University, Jinju 660-701, Republic of Korea.
authors.forename: Sung Chul
authors.initials: SC
authors.lastname: Shin
keywords: Compositions; Lactuca sativa L.; Night growth temperature; Polyphenols; Principal component analysis