Backgrounds : Pomelo (Citrus grandis Osbeck) is the kind of citrus fruit which is Dicotyledoneae belongs to Rutaceae and special product in Jeju island. According to the previous researches, coumarin, eliocitrin, naringin are identified and these kinds of constituents revealed to be effective as anticancer, antioxidant, and antidiabetic. Until recently, there are many investigations about its functional properties were reported, but investigation about biological activities depend on extraction conditions are not sufficient. Methods and Results : 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity was performed by the method of Blois with minor modification. After adding DPPH radical to each sample solutions, the mixtures were incubated in 30 minutes at aphotic place. Then, the degree of scavenging activity was recorded by microplate reader at 490 nm. The scavenging activity was expressed by RC50, which is the concentration of sample solution necessitated to scavenge 50% DPPH radical against negative control. For α-glucosidase inhibitory activity, the method using p-nitrophenyl-α-D-glucopyranoside (pNPG) was applied. To each samples, α-glucosidase and pNPG were mixed and incubated, consequently, Na2CO3 was added to terminate the reaction. Finally, absorbance was read at 450 nm. The same as DPPH radical scavenging activity, the inhibition was explicitly expressed by the amount of sample solution to inhibit 50% α-glucosidase, IC50. The 80% MeOH extract demonstrated the highest radical scavenging activity with 74.32±8.45 μg/ml. α-Glucosidase inhibitory activity was carried out to evaluate the inhibitory activity of sugar digestion and absorption and 60, 80% MeOH extract exhibited 416.35±11.07 μg/ml and 336.57±2.03 μg/ml, respectively. Conclusion : The DPPH radical scavenging and α-glucosidase inhibitory activity were evaluated in this study. The highest DPPH radical scavenging activity was seen in 80% Citrus grandis Osbeck MeOH extract, following 60% MeOH extract exhibited the second highest scavenging activity. Also, 80% MeOH extract showed 336.57±2.03 μg/ml, which was the highest α-glucosidase inhibition among all extracts.

본 연구에서는 새로운 프로바이오틱스를 선발하고자 protease를 생산하는 GRAS균주를 된장 및 청국장으로부터 분리하고 그 특성을 조사하였다. 분리한 균주를 분리 동정 한 결과 각각B. amyloliquefaciens CDD5, B. amyloliquefaciens CPD4 및B. amyloliquefaciens CGD3로 명명하였다. 분리균 주의 생육은 12시간 배양 시, 7.13~7.32 log CFU/mL로 최대 생육도를 보였으며 24시간까지 유지되다가 감소하는 경향 을 나타내었고, 그 중B. amyloliquefaciens CGD3의 protease 활성이9.21 U/mL로서가장높게나타났다. B. amyloliquefaciens 이 생산하는 protease 활성은 pH 7.0~10.0, 온도는 50℃에서 최적활성을 나타내었으며, casein에서 protease활성이 가장 우수하게 나타났다. pH, NaCl, glucose 농도를 달리한 배양 조건에 따른 B. amyloliquefaciens의 생육특성으로는 pH 5.0~10.0의 넓은 범위에서 생육하였고, NaCl은 12% 농도까 지 증식하였으며 glucose 5%까지는 생육하나 10% 농도부 터는 현저하게 생육이 낮아짐을 확인하였다. 또한 혈당저 하를 유도하는 α-glucosidase의 저해활성을 측정한 결과, B. amyloliquefaciens CPD4 및B. amyloliquefaciens CGD3에 서는 각각 96.65% 및 97.85%의 저해율을 나타내었다. 이러 한 결과는 특히 protease활성이 가장 우수하고 α-glucosidase 또한 높은 저해활성을 가진 B. amyloliquefaciens CGD3 균 주의 생육특성을 고려하여 단백질 분해 분야의 프로바이오 틱 적용 및 당뇨예방용 기능성식품 소재로의 가능성이 기대 된다.

This study investigated the changes of antioxidant activity and α-glucosidase inhibitory effect of Jerusalem artichoke (Helianthus tuberosus) 100% methanol extracts by various heat treatment. The contents of total phenolic and flavonoid compounds in methanol extract tended to increased gradually with the rise of temperature to 180℃. The maximum yield of gallic acid (51.52 ± 2.17mg/g extract weight) and quercetin (13.39 ± 0.03mg/g extract weight) were obtained with extraction temperature of 180℃ for 120min. In addition, the improving extraction efficiency resulted in the increased biological activities, such as electronic donation ability (EDA, 90.36± 0.57%), reducing power (Abs 1.14) and α-glucosidase inhibitory effect (92.14 ± 1.14%). Overall, the results of this study indicate that the optimum conditions for the extraction process were an extraction temperature at 180℃ for 120 min, and will provide the basis for future research on the improving extraction yield of phenolic and flavonoid compounds.

Compounds of isolated from roots extract of Pueraria thunbergiana were tested their inhibitory effects on α-glucosidase and α-amylase. Inhibitory activity of methylene chloride (MC) fraction and ethyl acetate (EA) fraction against α-glucosidase showed more than 60% at a concentration of 500μg/ml. Among the nine compounds tested on α-glucosidase, biochanin A, (-)-tuberosin and calycosin from MC fraction and daidzein from EA fraction were stronger inhibitors than acarbose (IC50=530μg/ml), and their IC50 were 9, 144, 328 and 20μg/ml, respectively. Biochanin A and (-)-tuberosin also inhibited α-amylase activity as like as acarbose IC50=20.5μg/ml), and their IC50 were 22 and 348μg/ml, respectively. Although daidzein was already known α-glucosidase inhibitory effects, it was newly evaluated that biochanin A and (-)-tuberosin inhibited α-glucosidase as well as α-amylase, and that calycosin did α-glucosidase.