Abstract
Panax notoginseng (PN) is one of the most valuable traditional Chinese medicines and has extensive pharmacological effects. Recent studies demonstrated that PN exhibited pharmacological effect related to Alzheimer's disease (AD). However, whether steaming process can boost its anti-AD activity is still unexplored. To fill this gap, effects of steaming durations and temperatures on the chemical characterization, neuroprotective and antioxidant activities of PN were systematically investigated in this study. HPLC fingerprint coupled with quantitative analysis demonstrated striking conversion of original saponins to less polar ones with the increase in the steaming time and temperature. In the viewpoint of anti-AD activity on neuroprotective and antioxidant effects, several steamed PN samples (110°C-6/8/10 h, 120°C -4/6 h samples) displayed a significant increase both in cell viability and oxygen radical absorption capacity (ORAC) values compared with the no steamed one (P < 0.01 or P < 0.005). Steaming temperature had the greater impact on the change of chemical composition and anti-AD activity of PN. Moreover, the spectrum-effect relationship analysis revealed that the transformed saponins were partially responsible for the increased neuroprotective and antioxidant effects of steamed PN. Therefore, steamed PN could be used as a potential crude drug for prevention and treatment of AD.