Abstract Recent decades have experienced a sharp increase in the incidence and prevalence of diabetes mellitus. One antidiabetic therapeutic approach is to reduce gastrointestinal glucose production and absorption through the inhibition of carbohydrate-digesting enzymes such as α- amylase and α-glucosidase and α-amylase. The aim of the current study was to screen six medicinal plant species, with alleged antidiabetic properties for α-glucosidase inhibitory activities. Powdered plant materials were extracted with acetone, and tested for ability to inhibit baker's yeast α-glucosidase and α-amylase activities. The largest mass (440 mg from 10 g) of the extract was obtained from Cassia abbreviata, while both Senna italica and Mormordica balsamina yielded the lowest mass of the extracts. Extracts of stem bark of C. abbreviata inhibited baker's yeast α-glucosidase activity with an IC50 of 0.6 mg/ml. This plant species had activity at low concentrations, with 1.0 mg/ml and above resulting in inhibition of over 70%. The other five plant extracts investigated had IC50 values of between 1.8 and 3.0 mg/ml. Senna italica only managed to inhibit the activity of enzyme-glucosidase at high concentrations with an IC50 value of 1.8 mg/ml, while Tinospora fragosa extracts resulted in about 55% inhibition of the activity of the enzyme at a concentration of 3.5 mg/ml, with an estimated IC50 value of 2.8 mg/ml. The bark extract of C. abbreviata was the most active inhibitor of the enzyme, based on the IC50 values (0.6 mg/ml). The bark extract of C. abbreviata contains non-competitive inhibitor(s) of α-glucosidase, reducing Vmax value of this enzyme from 5 mM·s–1 to 1.67 mM·s–1, while Km remained unchanged at 1.43 mMfor para-nitrophenyl glucopyranoside. Antioxidant activity of the extracts was also investigated. The C. abbreviata extract was more active as an antioxidant than the positive control, trolox. The extracts did not inhibit alphaamylase activity more than about 20% at the highest concentration tested.

Antioxidant-rich plant foods can inhibit starch and lipid digestion that are relevant to the management of type-II diabetes. Our objective was to compare the three phenolic substances (total phenolic, total flavonoids, and condensed tannin content) in crude, semi-purified extracts from eight types of foods (purified by XAD-7 column), five fractions (semi-purified extracts fractionated by Sephadex LH-20 column) from black legumes, and to compare their antioxidant capacities. The IC50 values of these crude extracts, semi-purified extracts and fractions against alpha-amylase, alpha-glucosidase and lipase were measured. Results showed that Fraction V from black soybean had the lowest IC50 value (0.25 mg/mL) against alpha-amylase; Fraction V from black bean had the lowest IC50 value (0.25 micro gram/mL) against alpha-glucosidase; Fraction IV of black bean had the lowest IC50 value (76 micro gram/mL) against lipase; myricetin showed the lowest IC50 value against alpha-amylase, alpha-glucosidase and lipase.

京都大学 / 新制・課程博士 / 博士(農学) / 甲第24247号 / 農博第2526号 / 新制||農||1094(附属図書館) / 学位論文||R4||N5418(農学部図書室) / 京都大学大学院農学研究科食品生物科学専攻 / (主査)教授 保川 清, 教授 井上 和生, 教授 谷 史人 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

Brown rice is a food ingredient which has high nutritious values. During germination, some nutritious and functional components are increased such as lysine, vitamin E, B1, B6, magnesium, calcium, iron… and especially γ – amino butyric acid. Enzyme activity will also change during the germination of the grains. The α – amylase activity of ungerminated grains is very low, only 34.91 UI/g. This is because the enzyme is hibernating and not activated. During germination, enzyme activity will increase. Submerge the Anhdao brown glutinous rice for 6 hours at 30oC in solutions with different pH values (2.0, 3.0, 4.0, 5.0, 6.0). The results show that at pH 3.0 the activity of α – amylase enzyme reaches the highest value of 82.93 UI/g. After the submersion, incubate the germinated brown rice in unentirely anaerobic condition at different temperature of 25, 30, 35, 37oC. The result showed that at 35oC after 24 hours of incubation, the α – amylase activity reaches the highest value of 89.82 UI/g. Examine the dynamic of changes of α – amylase activity against time at 35oC, we can see that in the first 28 hours the α – amylase activity increased significantly. Highest α – amylase activity reaches 97.10 UI/g after 28 hours of incubation. In reality, people usually use enzyme from germinated grains for many food manufacturing industries. α – amylase activity increases during incubation, which can bring promising prospects for processing sugar syrup and prebiotics food from germinated rice. / Gạo lứt là một nguyên liệu thực phẩm có giá trị dinh dưỡng cao. Trong quá trình nảy mầm các thành phần dinh dưỡng và chức năng của hạt gạo lứt được tăng lên ví dụ như lysine, các vitamin E, B1, B6, magie, canxi, sắt… và đặc biệt là γ – amino butyric acid. Hoạt tính của hệ enzyme sẽ thay đổi trong suốt quá trình nảy mầm của hạt gạo. Hoạt tính enzyme α – amylase của hạt gạo chưa nảy mầm là rất thấp, chỉ đạt 34,91UI/g, do enzyme của hạt đang ở trạng thái ngủ chưa được kích hoạt. Trong quá trình nảy mầm thì hoạt tính của α – amylase tăng lên. Tiến hành ngâm gạo lứt giống nếp Anh Đào trong 6 tiếng, ở 30oC trong nước ngâm có pH khác nhau (pH 2.0, 3.0, 4.0, 5.0, 6.0). Kết quả cho thấy, ở pH 3.0 hoạt độ enzyme α – amylase cao nhất đạt 82,93 UI/g. Sau quá trình ngâm, tiến hành ủ nẩy mầm gạo lứt yếm khí không hoàn toàn ở những nhiệt độ khác nhau 25, 30, 35, 37oC, kết quả ở 35oC sau 24 giờ ủ hoạt độ enzyme α – amylase đạt cao nhất là 89,82 UI/g. Khảo sát động học sự thay đổi của hoạt độ enzyme α – amylase theo thời gian ở nhiệt độ ủ 35oC, kết quả cho thấy,trong 28 giờ đầu hoạt độ của α – amylase tăng mạnh. Hoạt độ α – amylase cao nhất đạt 97,10 UI/g sau 28 giờ ủ. Trong thực tế người ta đã sử dụng enzyme từ hạt nảy mầm cho rất nhiều ngành sản xuất thực phẩm. Hoạt độ của α-amylase sau quá trình ủ mầm tăng lên, có thể đem lại triển vọng sử dụng để chế biến dịch đường và các sản phẩm có tính prebiotic từ gạo lứt nảy mầm.

This study has assessed the effects of pulse type and processing (soaking and cooking) on antinutritional factors (α-amylase inhibitor, trypsin inhibitor, chymotrypsin inhibitor, lectins, phytic acid and oxalates) in a wide range of Canadian pulses, using soybean as a control. The contents of these antinutrients in Canadian pulses varied widely, but the levels were generally lower than those found in soybean. Analysis of variance indicated that both pulse type and processing had significant effects (P < 0.0001) on the investigated seeds. Soaking markedly decreased the contents of α-amylase inhibitor, trypsin inhibitor, chymotrypsin inhibitor, lectins and oxalates, but had no impact on phytic acid. Cooking of presoaked seeds appeared to be more effective; all proteinaceous antinutrients (α-amylase inhibitor, trypsin inhibitor, chymotrypsin inhibitor and lectins) were decreased by 80 – 100%, and significant reductions in phytic acid content (11 – 39%) were observed for all pulses, except common beans and soybean. / February 2016

Diabetes mellitus is a growing threat to human health. Current pharmacological agents cause undesirable side-effects. Herbal remedies offer the potential for alternative treatment strategies that may prove more cost-effective and devoid of the undesirable side-effects. The purpose of this study was to evaluate the in vitro anti-diabetic activity of aqueous and methanol extracts of Sclerocarya birrea (A. Rich.) Hochst. (Anacardiaceae) and Ziziphus mucronata Willd. (Rhamnaceae), which are traditionally used for the treatment of diabetes mellitus in southern Africa. Polyphenolic contents of extracts were quantified using the aluminium trichloride and Folin-Ciocalteau methods. The capacity of individual extracts to scavenge both the 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and 2,2-diphenyl-1-picrylhydrazyl radicals was used as a measure of antioxidant activity. The inhibitory activities of the crude extracts of both plants on the enzymes, α-amylase and α-glucosidase, were determined using colorimetric assays. The effects of the crude extracts on cell viability was assessed in C2C12 myotubes, HepG2 hepatocarcinoma cells, 3T3-L1 adipocytes and RIN-m5F pancreatic β-islet cells, using the Sulforhodamine B assay. Fluorescence detection was used to investigate the effects of the crude extracts on glucose uptake in C2C12, HepG2 and 3T3-L1 cells. Insulin secretion was assessed in RIN-m5F cells, using ELISA. Crude extracts of both plants contained flavonoids and phenols, but flavonoid content was predominantly higher. All the extracts displayed antioxidant activity, with the methanol extract of S. birrea possessing the most potent free radical scavenging ability (IC50 = 2.16 μg/ml). Aqueous and methanol extracts of S. birrea displayed significantly (p < 0.05) greater inhibition of α-amylase, than the positive control, acarbose. Only the methanol extract of Z. mucronata inhibited α-amylase activity. Furthermore, crude extracts of both plants also displayed potent α-glucosidase inhibitory activity. Most of the crude extracts had low toxicity, where concentrations of 100 μg/ml of crude extract of the plants did not induce 50% cell death. iv Although no significant increase in insulin secretion from cultured RIN-m5F cells was noted, the crude extracts of both plants significantly (p < 0.05) increased glucose uptake in C2C12, HepG2 and 3T3-L1 cells, with efficacy significantly (p < 0.05) higher than the positive control, insulin. From the results, the plant extracts appear to exert their hypoglycaemic effects independently of insulin, via an extra-pancreatic mechanism, possibly involving interactions with the different receptors. An additive hypoglycaemic effect originates from the inhibition of both α-amylase and α-glucosidase. The findings of the present study provide evidence that S. birrea and Z. mucronata possess in vitro anti-diabetic activity. Further investigations are required to elucidate the mechanism(s) of action of the crude extracts using more targeted in vitro assays. / Dissertation (MSc)--University of Pretoria, 2013. / gm2014 / Pharmacology / unrestricted

Aims: The purpose of this thesis was to synthesize the current literature on alpha amylase as an emerging biomarker of microaspiration in mechanically ventilated patient. Methods: The methodology included a review and synthesis of pertinent research articles from 1981-2018, written in English language. Criteria for inclusion in the review were all articles that evaluated α- amylase in tracheal secretions or bronchoalveolar lavage fluid (BAL) as a diagnostic tool for identifying microaspiration. The search yielded 11 studies that were reviewed. Findings: The findings suggest that once aspiration occurs, the duration of α-amylase in the lungs requires further exploration to assist in interpretation of positive values. After these values are identified they need be used consistently used throughout practice of mechanically ventilated patients. Inconsistencies in the defining parameters of α-amylase were used with the thirteen studies. Conclusion: Testing amylase levels can require financial stability, standardized training, and timeliness of collecting the specimen. Alpha-amylase is a biomarker of microaspiration. Further research should be conducted to evaluate the biomarker capabilities of α-amylase to assist in early identification and/or prevention of microaspiration in mechanically ventilated patients. Implications for nursing policy practice, education, and considerations for upcoming research of α-amylase were reviewed with limitations to the study.

Fermentation and roasting of cocoa (Theobroma cacao) decrease levels of polyphenolic flavanol compounds. However, it is largely unknown how these changes in polyphenol levels caused by processing affect cocoa's anti-diabetic and anti-obesity bioactivities, such as inhibition of certain enzymes in the body. Polyphenol profiles, protein-binding abilities, presence of compounds termed oxidative polymers, and abilities to inhibit α-glucosidase, pancreatic α-amylase, lipase, and dipeptidyl peptidase-IV (DPP4) in vitro were compared between unfermented bean (UB), fermented bean (FB), unfermented liquor (UL), and fermented liquor (FL) cocoa extracts. Overall, there were significant decreases (p<0.05) in total polyphenols, flavanols, and anthocyanins between the two sets of unfermented and fermented cocoa extracts (CEs). All CEs effectively inhibited α-glucosidase (lowest IC50 = 90.0 ug/mL for UL) and moderately inhibited α-amylase (lowest IC50=183 ug/mL for FL), lipase (lowest IC25=65.5 ug/mL for FB), and DPP4 (lowest IC25=1585 ug/mL for FB) in dose-dependent manners. Fermentation and roasting of the samples affected inhibition of each enzyme differently (both processes enhanced α-amylase inhibition). Improved α-glucosidase and α-amylase inhibitions were correlated with presence of different classifications of oxidative polymers, suggesting that these compounds could be contributing to the bioactivities observed. Some α-glucosidase inhibition might be due to non-specific protein-binding. Improved DPP4 inhibition was strongly correlated to increased CE degree of polymerization. In conclusion, potential enzyme inhibition activities of cocoa were not necessarily negatively affected by the large polyphenol losses that occur during fermentation and roasting. Additionally, it is possible that more complex compounds could be present in cocoa that contribute to its potential anti-diabetic and anti-obesity bioactivities. / Master of Science in Life Sciences

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