Metabolite profiles and antibacterial and antioxidant activities of leaf extracts of five Lonicera species: a comparative study

Abstract Background Lonicera japonica Flos is widely used as a medicinal plant in China owing to its various pharmacological activities. However, little is known about the metabolic profile and antibacterial properties of the leaves of Lonicera species. The present study aimed to determine and compare the metabolite profiles and antibacterial and antioxidant activities of leaf extracts of five Lonicera species. Results 598 metabolites were identified based metabolomics using UHPLC-Q Exactive Orbitrap MS/MS in the five Lonicera species leaves. Among them, flavonoids and phenols compounds accounted for 13%. In Lonicera dasystyla, 110 differential metabolites were found compared to those in the other Lonicera species, of which flavonoids and phenols accounted for 20% and 10%, respectively. Compared to other Lonicera species leaves, the contents of total phenol, total flavonoid, antioxidant activities and anti-bacterial capacities were considerably higher in Lonicera hypoglauca and lower in L. dasystyla. The contents of total phenol and total flavonoid in L. hypoglauca were 95.86% and 201.64% higher than those in L. dasystyla. The RPA value in L. hypoglauca was 93.27% higher than the value of L. dasystyla, respectively. The content of 4, 5-dicaffeoylquninic acid in L. hypoglauca was 4.814 mg g−1, which was 302.85% higher than that of L. dasystyla. Besides, Chlorogenic acid was most high in leaves of L. japonica and reached 15 mg g−1, which was 209.34% higher than that of L. dasystyla. Moreover, correlation analysis showed most flavonoids, phenols, and coumarins were positively correlated with antioxidant activities and antibacterial capacities. Conclusions This study identified the difference of metabolites in leaves of five Lonicera species, antioxidant abilities and inhibition effects of leaf extracts on pathogens, which provides a potential information for further application of Lonicera leaves. Graphical Abstrac