Bioactive components in Panax notoginseng and Panax quinquefolium leaves and their antioxidant, antihypertensive and anti-inflammatory capacities

Roots of Panax notoginseng and Panax quinquefolium that are native in China and North America, are widely used as traditional herbal medicines. As non-medicinally utilized parts, the leaves of P. notoginseng (LPN) and P. quinquefolium (LPQ) are also rich in bioactive ingredients, however their metabolites and bioactive capacities require deeply research. In this study, 1028 potential bioactive ingredients in LPN and LPQ were identified by targeted metabolomics methods, including 60 triterpenoid saponins and 178 flavonoids, etc. Ginsenoside Rb3 (5.71 ± 0.23) mg/g, notoginsenoside Fd (1.68 ± 0.07) mg/g, notoginsenoside Fc (1.60 ± 0.04) mg/g, gallocatechin gallate (3.64 ± 0.67) mg/g and gallocatechin (1.91 ± 0.74) mg/g in LPN, as well as ginsenoside Rb3 (5.75 ± 0.09) mg/g, ginsenoside Rg1 (2.61 ± 0.02) mg/g, ginsenoside Rb2 (0.88 ± 0.08) mg/g, gallocatechin gallate (20.70 ± 0.22) mg/g and gallocatechin (0.82 ± 0.01) mg/g in LPQ were measured using high performance liquid chromatography. Both LPN and LPQ showed good antioxidant activities with IC50 values of 0.32–1.91 mg/mL for scavenging ABTS, DPPH; and the total antioxidant capacities at 2.00 mg/mL were 86.73 ± 0.54% and 70.03 ± 3.38%. LPN and LPQ inhibited angiotensin I-converting enzyme with IC50 values of 3.59 and 1.37 mg/mL, respectively, reflecting their antihypertensive activities. Both samples inhibited the production of the inflammatory cytokines TNF-α and IL-6 in lipopolysaccharide induced RAW264.7 cells, showing anti-inflammatory effects. In conclusion, as the non-medicinal parts of important traditional herbal medicinal plants, LPN and LPQ are rich in bioactive metabolites and show good antioxidant, antihypertensive and anti-inflammatory capacities, revealing their potential as sources of natural medicines.