Supplementary file 1_UHPLC-Q-TOF-MS/MS profiling of resin glycosides and their lipase inhibitory activity in leaves of selected sweet potato (Ipomoea batatas L.) cultivars.docx

IntroductionResin glycosides (RGs) found in the aerial parts of sweet potato are health promoting agents that can be reclaimed from the by-products of sweet potato plantation as agriceuticals for combating obesity. However, RGs have complex structural variations across various sweet potato cultivars, along with an unclear structure–activity relationship. To address this gap, nine types of sweet potato leaves were evaluated, including “Shangshu 19”, “Xuzi 20-1”, “Xushu 24”, “Xushu 32”, “Yanshu 25”, “Blackheart”, “Blackie”, and two “Beniazuma” samples.
MethodsRG-rich extracts were obtained from sweet potato leaves by using dichloromethane extraction. Pancreatic lipase (PL) inhibitory activity was then determined by a p-nitrophenyl palmitate (pNPP)-based assay. Individual RG profiles were characterized and semi-quantified by UHPLC–Q-TOF-MS/MS, followed by multivariate analysis to evaluate cultivar-dependent variations and identify spectral features associated with PL inhibition.
ResultsXushu 32 and Blackheart cultivars exhibited the highest PL inhibitory activities with an Orlistat equivalent (OE) of 2.44 ± 0.30 and 2.02 ± 0.10 ng orlistat/μg extracts, respectively. In total, 128 RGs were tentatively identified based on UHPLC–Q-TOF-MS/MS analysis. Multivariate analysis revealed cultivar-dependent differences in RG profiles and identified four RGs as potential marker compounds associated with PL inhibition. All four RGs were pentasaccharides featuring 2-methylbutyric and dodecanoic acid as side chains. Further mechanistic study revealed that long-chain fatty acid esters or a macrocyclic lactone moiety on the RG backbone may play a key role in conferring inhibition.
DiscussionTaken together, these findings may serve as valuable guidelines for foodomic analysis of RGs and cultivar selection in developing anti-obesity functional foods derived from agricultural by-products.In addition, we would like to double-check that the formatting of Table 1 is maintained as in the original manuscript we provided. The current proof version includes additional internal table lines that slightly alter the intended meaning of the table.