RESUMEN
The objective of our study was to analyse the extracts from six medicinal herb roots (marshmallow, dandelion, liquorice, angelica, burdock, and comfrey) in terms of antioxidant capacity (ABTS, DPPH) and inhibition of advanced glycation end product (AGEs) formation. The quantification of phenolic acids and flavonoids was analysed using the UHPLC-DAD-MS method. Fifteen polyphenolic compounds were detected in the studied herbs. The higher number of polyphenols were found in marshmallows (ten polyphenols), while the lowest was in comfrey (five compounds). Liquorice root revealed the highest individual phenolic concentration (382 µg/g dm) with the higher contribution of kaempferol-3-O-rutinoside. Comfrey root extract was characterised by the most abundant TPC (Total Phenolic Content) value (29.79 mg GAE/ g dm). Burdock and comfrey showed the strongest anti-AGE activity studies with the BDA-GLU model. Burdock root was also characterised by the highest anti-AGE activity in the BSA-MGO model. The highest antioxidant capacity was determined by ABTS (72.12 µmol TE/g dw) and DPPH (143.01 µmol TE/g dw) assays for comfrey extract. The p-coumaric acid content was significantly correlated with anti-AGE activity determined by the BSA-MGO model. This research sheds new light on the bioactivity of root herbs, explaining the role of p-coumaric acid in preventing diabetes.
RESUMEN
Herbs are characterized by a high content of biologically active substances that positively affect human health. Phenolic compounds are one of the main bioactive compounds in these plants with highly beneficial properties (e.g., anti-carcinogenic, cardioprotective, immune system support and antibacterial). Therefore, this study aimed to determine the composition of free and bound phenolic compounds and antioxidant activity in 10 different herbs (bogbean leaves, sage leaves, whole Indian hemp, whole heartsease, whole horsetail, whole blessed thistle, whole thyme, chamomile flower, corn silk and pine buds). Phenolic compounds were analyzed using the HPLC-TOF-MS/MS method, total phenolic (TP) and flavonoid (TF) contents were measured using spectrophotometric methods, while antioxidant activity was determined by ABTS and DPPH assays. The highest content of free TP was found in thyme, while sage was characterized by the highest range of these compounds released from ester and glycosidic derivatives by hydrolysis. In turn, the highest values of TF in non-hydrolyzed extracts were found in Indian hemp. The highest values of TF, including bound phenols were observed in extracts obtained from sage leaves. In the analyzed herbs thirty-three phenolic compounds were found, constituting 16 phenolic acids, 9 flavonoids and eight stilbenes. Moreover, the analyzed compounds appeared in the bound form than in the free form. The antioxidant activity of herb extracts differed significantly across varieties (P < 0.05). The research showed that each tested herb possesses its own fingerprint of phenolic compounds and antioxidant properties.
