title: Analysis of flavonoids from lotus (Nelumbo nucifera) leaves using high performance liquid chromatography/photodiode array detector tandem electrospray ionization mass spectrometry and an extraction method optimized by orthogonal design.
abstract: The extraction protocol of flavonoids from lotus (Nelumbo nucifera) leaves was optimized through an orthogonal design. The solvent was the most important factor comparing solvent, solvent:tissue ratio, extraction time, and temperature. The highest yield of flavonoids was achieved with 70% methanol-water and a solvent:tissue ratio of 30:1 at 4 °C for 36 h. The optimized analytical method for HPLC was a multi-step gradient elution using 0.5% formic acid (A) and CH₃CN containing 0.1% formic acid (B), at a flow rate of 0.6 mL/min. Using this optimized method, thirteen flavonoids were simultaneously separated and identified by high performance liquid chromatography coupled with photodiode array detection/electrospray ionization mass spectrometry (HPLC/DAD/ESI-MS(n)). Five of the bioactive compounds are reported in lotus leaves for the first time. The flavonoid content of the leaves of three representative cultivars was assessed under the optimized extraction and HPLC analytical conditions, and the seed-producing cultivar 'Baijianlian' had the highest flavonoid content compared with rhizome-producing 'Zhimahuoulian' and wild floral cultivar 'Honglian'.
authors.affiliation: Key Laboratory of Plant Germplasm Enhancement and Speciality Agriculture, Wuhan Botanical Garden, The Chinese Academy of Sciences, Wuhan 430074, China.
authors.forename: Sha
authors.initials: S
authors.lastname: Chen
authors.forename: Ben-Hong
authors.initials: BH
authors.lastname: Wu
authors.forename: Jin-Bao
authors.initials: JB
authors.lastname: Fang
authors.forename: Yan-Ling
authors.initials: YL
authors.lastname: Liu
authors.forename: Hao-Hao
authors.initials: HH
authors.lastname: Zhang
authors.forename: Lin-Chuan
authors.initials: LC
authors.lastname: Fang
authors.forename: Le
authors.initials: L
authors.lastname: Guan
authors.forename: Shao-Hua
authors.initials: SH
authors.lastname: Li
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005419:Flavonoids / Q000032:analysis*; D016014:Linear Models; D000432:Methanol; D031653:Nelumbo / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry; D015203:Reproducibility of Results; D053719:Tandem Mass Spectrometry / Q000379:methods*; D014867:Water
chemical_list: D005419:Flavonoids; D014867:Water; D000432:Methanol