Antioxidant capacity and phenolic compounds of Lonicerae macranthoides by HPLC–DAD–QTOF-MS/MS

•Extract solvent affected TPC, TFC and the antioxidant activities.•Thirty-one antioxidants were screened and identified from L. macranthoides.•Twenty-one compounds were discovered from L. macranthoide for the first time.•L. macranthoide was a potential antioxidants resource.

Lonicerae macranthoides with strong antioxidant activity is commonly used in traditional Chinese medicine and folk tea/beverage. However, detailed information about its antioxidant activity and bioactive compounds is limited. Then at first, we comparatively evaluated total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activities of water extract, petroleum ether, ethyl acetate and n-butanol fractions of L. macranthoides. Ethyl acetate fraction exhibited the highest level of TPC (207.38 mg GAE/g DW), TFC (53.06 mg RE/g DW) and the best DPPH scavenge activity and reducing power. n-Butanol fraction showed the best ABTS+ and O2− scavenging activities. Interestingly, water extract, ethyl acetate and n-butanol fractions showed stronger antioxidant activities than positive control, butylated hydroxytoluene (BHT). After that, thirty-one antioxidant phenolic compounds, including twenty-two phenolic acids and nine flavonoids, were screened by DPPH–HPLC experiment and then identified using HPLC–DAD–QTOF-MS/MS. It is noted that twenty-one compounds (1, 3–4, 6–17, 19, 23, 26, 28–29, and 31), as far as was known, were discovered from L. macranthoide for the first time, and eleven of them (3–4, 10–17, and 23) were reported in Lonicera species for the first time. Results indicated that L. macranthoides could serve as promising source of rich antioxidants in foods, beverages and medicines for health promotion.

Graphical abstractProfiling of antioxidant components in Lonicerae macranthoides.Figure optionsDownload full-size imageDownload as PowerPoint slide