Analysis of Flavonoids in Lotus (Nelumbo nucifera) Leaves and Their Antioxidant Activity Using Macroporous Resin Chromatography Coupled with LC-MS/MS and Antioxidant Biochemical Assays

Abstract

Lotus (Nelumbo nucifera) leaves, a traditional Chinese medicinal herb, are rich in flavonoids.In an effort to thoroughly analyze their flavonoid components, macroporous resin chromatography coupled with HPLC-MS/MS was employed to simultaneously enrich and identify flavonoids from lotus leaves. Flavonoids extracted from lotus leaves were selectively enriched in the macroporous resin column, eluted subsequently as fraction II, and successively subjected to analysis with the HPLC-MS/MS and bioactivity assays. Altogether, fourteen flavonoids were identified, four of which were identified from lotus leaves for the first time, including quercetin 3-O-rhamnopyranosyl-(1→2)-glucopyranoside, quercetin 3-O-arabinoside, diosmetin 7-O-hexose, and isorhamnetin 3-O-arabinopyranosyl-(1→2)-glucopyranoside. Further bioactivity assays revealed that these flavonoids from lotus leaves possess strong antioxidant activity, and demonstrate very good potential to be explored as food supplements or even pharmaceutical products to improve human health.

Lotus Flavonoids and Phenolic Acids: Health Promotion and Safe Consumption Dosages

“…At present, it has received extensive attention and is also being used in combination with chromatography to achieve the best separation and highest purity of compounds. Zhu, Wu, Jiao, Yang, and Guo () have reported enrichment in the flavonoids of lotus leaves when fractionated using MARs coupled with LC‐MS/MS. The content of Que‐3‐Gln in the lotus leaves was found to have increased by 50.1%, with a purity above 98.00%, when LX‐5 MARs was used in combination with semi‐preparative HPLC (Li, Sun, Li, Yang, & Qi, ).…”

Quantitative Analysis and Comparison of Flavonoids in Lotus Plumules of Four Representative Lotus Cultivars

“…Optimization of LC Conditions. The chromatographic separation condition was referred to Zhu et al [18] and Chen et al [16] and some modifications were made to achieve a faster and better separation. Lotus plumules from XT (Xiangtan in Hunan province) were used to optimize chromatographic conditions.…”

“…As referred to Zhu et al [18] with some minor modifications, 20 g of dried powders of lotus plumule was ultrasonically extracted with 200 mL of 70% ethanol for 40 min and then the extracts were filtered with filter paper. The residues were re-extracted twice and filtered.…”

“…Bailian, Xuanlian, Xianglian, Jianlian), which were collected from four different districts. Their total and individual content of flavonoids were determined by combining macroporous resin chromatography with high-performance liquid chromatography (MPRC-HPLC) method, which was developed for the simultaneous enrichment and analysis of flavonoids from lotus leaves, recently [18]. It would be of key importance for the following reasons.…”

Effects of thermal processing methods and simulated digestion on the phenolic content and antioxidant activity of lotus leaves

“…Lotus leaf is harvested in summer and fall, as a perennial aquatic plant species, and is widely distributed throughout Asia (Hussain, Li, Jin, Yan, & Wang, ; Li, Sun, Li, Yang, & Qi, ; Zhu, Wu, Jiao, Yang, & Guo, ). According to the ancient literature of traditional Chinese medicine, lotus leaf has a bitter taste, can clear up summer heat, drain dampness, induce antibacterial activity, remove heart‐fire and heart‐heat, cool blood, and arrest bleeding.…”