ABSTRACT
The ultrasound-assisted aqueous extraction of chlorogenic acid (CGA) and cynarin with the impact of inulin from burdock (Arctium lappa L.) roots was investigated. Three extraction modes, ultrasound at 40 kHz/300 W (U-40), ultrasound at 120 kHz/300 W (U-120), and shaking at 120 rpm (S-120), were compared. The effects of process parameters on the extraction of polyphenols, CGA, cynarin, inulin, and antioxidant activity using U-40 were evaluated. In 10 min, 50 °C, and 1/30 (g/mL-water) of solid-to-liquid ratio, the order of CGA content in the dried burdock root powder (DBR) was U-40 (484.65 µg/g-DBR) > U-120 (369.93 µg/g-DBR) > S-120 (176.99 µg/g-DBR), while the order of cynarin content in DBR was U-120 (376.47 µg/g-DBR) > U-40 (341.54 µg/g-DBR) > S-120 (330.44 µg/g-DBR), showing the selective extraction of CGA and cynarin between using 40 and 120 kHz of ultrasound. The profiles of increase and then decrease in free CGA and cynarin concentrations against time revealed their degradation, including their interactions with the abundant inulin. The kinetic model, considering extraction followed by degradation, was proposed to describe the variations of free CGA and cynarin against time. This study provides an effective method using water to extract CGA, cynarin, and inulin from burdock roots.
ABSTRACT
The characteristics of nuclear calcium regulation were investigated in isolated rabbit myocardial nuclei. It was found that calcium concentration in myocardial nuclei was 2.6 fold more than that in myocardial homogenate (P<0.O1), and the nuclear calcium content was only l/6 of the total cellular calcium. Ca-ATPase of myocardial nuclei was [Ca(2+] and [ATP] dependent. [Ca2+] dependent K(a) and V(max) at 2.O mmol/L [ATP] were 226 nmol/L and 3 460 nmol/(h.mg) protein respectively. [ATP] dependent K(m) value and V(max) at 400 nmol/L [Ca2+] were 376.5 &mgr;mol/L and 2 445 nmol/(h.mg) protein respectively. A positive correlation between nuclear 45)Ca2+ transport and Ca-ATPase activity was observed (r=O.945, P<0.01). The above result suggests that myocardial nuclei are able to transport calcium actively. The pathophysiological role of myocardial nuclear calcium transport should be further determined.
