Buckwheat hulls, generally discarded as waste, have been known to possess various flavonoids and high antioxidant activities. The objective of this study was to determine effect of extracting solvents [water, ethanol (20%, 50%, 80%, and 100%), methanol, and acetone] on total phenolic content, flavonoid content and composition, and antioxidant activities of common and tartary buckwheat hull extracts. Antioxidative effect of common and tartary buckwheat hull extracts on lipids in mayonnaise was also investigated. Vitexin, isovitexin, isoorientin, orientin, rutin, isoquercetin, and quercetin were identified in the common buckwheat hull extracts, while rutin, quercetin, isoorientin, and isoquercetin were in the tartary buckwheat hull extracts. The methanol and 80% ethanol extracts had more flavonoids than the others, while the aqueous ethanol extracts from both of the hulls had more total phenolics and antioxidant activities. Oxidative stability of lipids in mayonnaises added with common and tartary buckwheat hull extracts (0.02 and 0.08%, w/w) prepared by 50% ethanol were higher than that in the mayonnaise with butylated hydroxytoluene (0.02%) and control. Oxidative stability was not significantly different between the mayonnaises added with the two buckwheat hull extracts.

Red ginseng (RG) and black ginseng (BG, CJ EnerG) were prepared from fresh ginseng using one and nine cycles of steaming and drying, respectively. This process reduces the molecular weight (MW) of ginsenoside-active compounds in ginseng by removing sugar moieties from their dammaranes. We compared the pharmacokinetic characteristics of ginsenosides between BG comprising mainly low-MW ginsenosides (Rg3, Rg5, Rk1, and Rh1) and RG that predominantly contains high-MW ginsenosides (Rb1, Rb2, Rc, Rd, Re, and Rg1). The safety profiles and tolerability were also studied using a randomized, double-blind, single-dose, crossover clinical trial. A combination of Rb1, Rg1, and Rg3, well-known representative and functional RG components, exhibited a 1-h faster absorption rate (Tmax) and 58% higher exposure (24-h area under the concentration–time curve, AUC24) in BG than in RG. Furthermore, the combination of Rg3, Rg5, and Rk1, the major and most efficient components in BG, displayed 824% higher absorption (AUC24) in BG than in RG. The total ginsenoside showed a 5-h rapid intestinal absorption (Tmax) and 79% greater systemic exposure (AUC24) in BG than in RG. No clinically significant findings were observed in terms of safety or tolerability. Thus, BG extract was more effective than RG extract.