Derived from India, Moringa oleifera Lam. has been mainly introduced into Yunnan, Guangdong, Hainan and Fujian provinces in recent decades. Presently, plenty of studies have indicated the bioactivities of M. oleifera, such as anti-inflammatory, antibacterial, anti-cancer, hypoglycemic, hypolipidemic and antioxidant activities, etc., especially in terms of antioxidant activity. However, it is still a puzzle which individual compounds in M. oleifera leave contribute most to its outstanding antioxidant capacity. Therefore, it is of great necessity to screen out the most effective components of M. oleifera leaves. 

Supervised by Prof. GUO Mingquan from Wuhan Botanical Garden, XU Yongbing aimed to find out the potential bioactive components with the most potent antioxidant capacity from M. oleifera leaves.   

For this purpose, the high-performance liquid chromatography-ultraviolet-electrospray ionization tandem mass spectrometry (HPLC-UV/ESI-MS/MS) was firstly applied to establish the chromatography fingerprints of M. oleifera leaves. Three types of antioxidant determination methods (DPPH, ABTS and FRAP assays) were carried out to evaluate the antioxidant capacity of M. oleifera leaf extracts. Finally, the chemometrics analysis was used to correlate t he antioxidant capacity with chromatography fingerprints of M. oleifera leaves. 

A total of 24 common peaks were identified in M. oleifera leaves by LC-MS. By chemometrics analysis, four main antioxidant active ingredients were screened from M. oleifera leaves, namely kaempferol 3-O-rutinoside, quercetin 3-O-(6′′-malonyl-glucoside), kaempferol 3-O-glucoside, and quercetin derivative, respectively.   

This study provides a theoretical support for M. oleifera leaves as a natural source of antioxidants for better applications in the future, and also provides an alternative method to screen for the potential antioxidant components without conventional phytochemical separation and purification. 

Relevant results have been published in Phytochemical Analysis entitled “Correlations between Phytochemical Fingerprints of Moringa oleifera Leaf Extracts and Their Antioxidant Activities Revealed by Chemometrics Analysis”. This study was financially supported by the National Natural Science Foundation of China, the Youth Innovation Promotion Association of the Chinese Academy of Science and Natural Science Foundation of Hubei Province. 

 The base peak chromatographic fingerprints of fifteen batches of extracts from M. oleifera leaves (Image by WBG)