Isolation And Identification Of Flavonoids In Nelumbinis Plumula And The Comparison Of Flavonoids In Nelumbinis Plumula From Four Different Districts

Nelumbinis Plumula, the green seed embryo of the mature lotus seed belonging to the Nymphaeaceae Nelumbo, is a traditional Chinese medicine. Lotus is widely distributed in China, and the four representative ones which are respectively distributed in Xiangtan (Hunan province) called xianglian, Guangchang (Jiangxi province) called bailian, Wuyi (Zhejiang province) called xuanlian and Jianning (Fujian province) called jianlian, are the most famous cultivars in Chinese history. It has been proved that alkaloids and flavonoids are the two major bioactive compounds in Nelumbinis Plumula. For the studies on flavonoids in Nelumbinis Plumulas, previous work mostly focused on the extraction and determination of the total flavonoids, as well as the anti-oxidant and anti-bacterial activities of the total flavonoids. However, to further investigate the flavonoids in Nelumbinis Plumula, Nelumbinis Plumulas from Guangchang were used as materials to isolate the pure flavonoid compounds in this work. Meanwhile, to compare the types and contents of flavonoids of the four representative cultivars of Nelumbinis Plumulas, the flavonoids of these cultivars from four different districts were quantitatively and qualitatively analyzed.5 kg of dried Nelumbinis Plumula from Guangchang were extracted with ethanol and then purified and isolated with liquid/liquid partitioning, macro-porous resin column, silica-gel column chromatography, sephadex column chromatography and preparation high performance liquid chromatography (Pre-HPLC). Eleven compounds were isolated from the Nelumbinis Plumula including eight flavonoid compounds and three other compounds, namely, isorhamnetin-3-O-rutinoside, luteolin-6-C-glucoside (isoorientin), rutin, apigenin-6-C-glucoside (isovitexin), luteolin-7-O-neohesperidoside, luteolin-8-C-glucoside (orientin), quercetin-3-O-galactoside (hyperoside), quercetin-3-O-glucoside (isoquercitrin), icariside D2,4-hydroxyphenethyl alcohol, thalifoline, in which hyperoside, luteolin-7-O-neohesperidoside, icariside D2, and thalifoline are isolated from Nelumbinis Plumula for the first time. The isolation and identification of these compounds will further reveal the chemical composition of Nelumbinis Plumula and provide new chemical source for the bioactivity studies.Nelumbinis Plumulas of four representative cultivars were extracted with ethanol and purified with macro-porous D101 resin chromatography to obtain the total flavonoids of Nelumbinis Plumula. The separation conditions of the flavonoids were optimized using high performance liquid chromatography (HPLC). Under the optimized separation conditions, high performance liquid chromatography tandem electrospray ionization mass spectrometry (HPLC-ESI-MS) was used to identify the flavonoids in Nelumbinis Plumula. Finally, the method base on HPLC was established and validated to quantify the flavonoids of four representative Nelumbinis Plumulas. The results showed that twenty flavonoids were detected in all the Nelumbinis Plumulas from the four different districts, indicating that the composition of flavonoid in Nelumbinis Plumula from the four different districts were the same. However, the total flavonoid contents among the four cultivars were different, which are 1237.62 mg/100g for Xianglian (Xiangtan, Hunan province),981.28 mg/100g for Jianlian (Jianning, Fujian province),1702.03 mg/100g for Bailian (Guangchang, Jiangxi province), and 1628.78 mg/100g for Xuanlian (Wuyi, Zhejiang province), respectively. Cultivar of bailian from Guangchang was detected to have the most total flavonoid content which was almost twice as that of Nelumbinis Plumula from Jianning. Although the total flavonoid contents among the four representative cultivars were significantly different, the percentage of flavonoid C-glycosides in the total flavonoids among the four cultivars was much similar, which are 81.88% for Xianglian,80.43% for Jianlian,82.07% for Bailian, and 79.50% for Xuanlian, respectively. The comparison of the flavonoid contents of the four cultivars will be of great interest in guarantying and controlling the quality of Nelumbinis Plumulas and screening Nelumbinis Plumula curtivars with high flavonoid content.