Metabolic Profiling and Antioxidant Analysis for the Juvenile Red Fading Leaves of Sweetpotato

Abstract

Leaves of sweetpotato (Ipomoea batatas L.) are promising healthy leafy vegetable. Juvenile red fading (JRF) leaves of sweetpotato, with anthocyanins in young leaves, are good candidates for developing functional vegetables. Here, metabolic profiling and possible antioxidants were analyzed for five leaf stages of the sweetpotato cultivar “Chuanshan Zi”. The contents of anthocyanins, total phenolics, and flavonoids all declined during leaf maturation, corresponding to declining antioxidant activities. By widely targeted metabolomics, we characterized 449 metabolites belonging to 23 classes. A total of 193 secondary metabolites were identified, including 82 simple phenols, 85 flavonoids, 18 alkaloids, and eight terpenes. Analysis of the metabolic data indicates that the antioxidant capacity of sweetpotato leaves is the combined result of anthocyanins and many other colorless compounds. Increased levels of “chlorogenic acid methyl ester”, a compromised form of chlorogenic acid, significantly correlated with the declined antioxidant abilities. Besides anthocyanins, some significant metabolites contributing to the high antioxidant property of the sweetpotato leaves were highlighted, including chlorogenic acids, isorhamnetin glycosides, trans-4-hydroxycinnamic acid methyl ester, 4-methoxycinnamic acid, esculetin, caffeate, and trigonelline. This study provides metabolic data for the utilization of sweetpotato leaves as food sources, and sheds light on the metabolomic change for JRF leaves of other plants.

Bioactive Compounds, Antioxidant Activities, and HPLC Analysis of Nine Edible Sprouts in Cambodia

“…The extract or compound contains molecular structures that bear active hydroxyl groups, such as polyphenols and flavonoids, which are potent radical scavengers [ 19 ]. The antioxidant activities of plant extracts were enhanced by the presence of phenolic compounds, flavonoids, alkaloids, anthocyanin compounds, and other secondary metabolites [ 20 , 21 ].…”

Pre-Treatment, Extraction Solvent, and Color Stability of Anthocyanins from Purple Sweetpotato

“…The measurements were according to Shi et al [ 24 ]. About 1 g fresh sample or 0.35 g dry powder was homogenized with 20 mL of 75% ethanol.…”