Comparison of Free, Esterified, and Insoluble-Bound Phenolics and Their Bioactivities in Three Organs of Lonicera japonica and L. macranthoides

• Published in: Molecules (Basel, Switzerland) Vol. 24; no. 5; p. 970
• Main Authors: Yu, Miao, Yang, Lingguang, Xue, Qiang, Yin, Peipei, Sun, Liwei, Liu, Yujun
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 09.03.2019; MDPI
• Subjects: Acids; antioxidant activity; Antioxidants; Biological activity; Caffeic acid; Chlorogenic acid; Diabetes; DNA damage; DNA protection; Esterification; Flavonoids; Flowers & plants; Free radicals; Herbal medicine; Investigations; Liquid chromatography; Lonicera japonica; Lonicera macranthoides; Mass spectrometry; Mass spectroscopy; Organs; Phenolic compounds; phenolics; Phenols; Quadrupoles; UPLC-DAD–QTOF-MS/MS; DNA protection; Lonicera macranthoides; antioxidant activity; UPLC-DAD–QTOF-MS/MS; Lonicera japonica; phenolics
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules24050970

Dried flower buds of and have long been used as herbs in numerous Chinese traditional medicines. Comparisons of three phenolic fractions (i.e., free, esterified, and insoluble-bound phenolics) in three different organs (i.e., flower, leaf, and stem) of the two species revealed that the free phenolics were the highest in terms of total phenol and total flavonoid content, composed of the most numerous phenolics and flavonoids; thus, they exhibited the most excellent antioxidant activities (2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonate) (ABTS), and oxygen radical absorbance capacity (ORAC)), as well as protective effects on DNA damage induced by free radicals. In identical free and esterified phenolics of a same organ, higher contents and bioactivities were observed in than in . Phenolics identified by ultra-performance liquid chromatography with a diode array detector, alongside tandem mass spectrometry coupled with a quadrupole time-of-flight mass spectrometer (UPLC-DAD⁻QTOF-MS/MS) mainly included chlorogenic acid and its five derivatives, three flavonoids that were only found in the free phenolic fraction and closely correlated with its bioactivity, and caffeic acid that was the major contributor to antioxidant activity of the esterified and insoluble-bound phenolic fractions. It was, thus, concluded that, like , , which was underestimated since being separately listed by the 2010 edition of the Chinese Pharmacopoeia, is also a good (and better) herbal medicine.