α-amylase detection methods and applications / 生物工程学报

α-amylase is an endonucleoside hydrolase that hydrolyzes the α-1, 4-glycosidic bonds inside polysaccharides, such as starch, to generate oligosaccharides, dextrins, maltotriose, maltose and a small amount of glucose. Due to the importance of α-amylase in food industry, human health monitoring and pharmaceuticals, detection of its activity is widely required in the breeding of α-amylase producing strains, in vitro diagnosis, development of diabetes drugs, and the control of food quality. In recent years, many new α-amylase detection methods have been developed with improved speed and sensitivity. This review summarized recent processes in the development and applications of new α-amylase detection methods. The major principle of these detection methods were introduced, and their advantages and disadvantages were compared to facilitate future development and applications of α-amylase detection methods.

The effects of yoga and mindful meditation on elderly care worker’s burnout: a CONSORT-compliant randomized controlled trial / Journal of Rural Medicine

Objectives: This study aims to investigate the effects of mindful meditation and yoga on reducing burnout and stress in care workers who assist elderly individuals. Knowing how to reduce burnout is important because that of care workers is associated with the quality of client care, worker productivity, and job turnover.Patients and Methods: The participants included 44 care workers who worked for elderly care facilities in rural Fukuoka. They were randomly assigned to one of three intervention groups: control, yoga, or mindfulness. In the yoga intervention group, a certified yoga instructor taught a 60-minute yoga session each week for six weeks. In the mindfulness group, an experienced medical doctor instructed a mindful meditation program for the same length. Participants were asked to complete the Japanese Burnout Scale (JBS), and the research team collected the level of α-amylase in saliva using NIPRO: T-110-N pre- and post-interventions.Results: MANOVA was performed with each intervention (control, yoga, mindfulness) as the independent variable on the three subscales of the JBS (emotional exhaustion, depersonalization, and personal achievement) and a biomarker of stress level (α-amylase). The results indicated a significant main effect of interventions, and a follow-up ANOVA showed a significant effect of interventions on emotional exhaustion and personal achievement.Conclusion: The results indicate that practicing mindful meditation or yoga for 60 minutes once a week for six weeks can reduce care workers’ burnout. This study was notable because the biomarker of stress also improved. It is strongly recommended and encouraged that institutions caring for the elderly population provide mindful meditation or yoga intervention to reduce burnout, which benefits not only care workers but also their clients.

Advances in identification of biomarkers for aspiration: from laboratory research to clinical practice / 中华老年医学杂志

Aspiration is the entry of oropharyngeal or gastric contents into the lower respiratory tract through the glottis, a common and important cause of death in elderly patients due to lung infections.However, a lack of accurate and rapid clinical methods for the diagnosis of aspiration leads to misdiagnosis, missed diagnosis or delayed diagnosis of aspiration, especially aspiration pneumonia.In recent years, with further research into the mechanisms of aspiration syndromes, multiple aspiration biomarkers with potential and clinical translational value have been found, and may help early detection of aspiration and have important and practical significance for elderly health.Therefore, this article reviews aspiration biomarkers such as pepsin, α-amylase, bile acid and other potential biomarkers as well as current relevant research, detection methods, their clinical value and prospects concerning challenges and directions of innovation in future research.

Antidiabetic effect of Chrysophyllum albidum is mediated by enzyme inhibition and enhancement of glucose uptake via 3T3-L1 adipocytes and C2C12 myotubes

Objective: To investigate the in vivo and in vitro antidiabetic potential of Chrysophyllum albidum. Methods: The effects of oral treatment with hydro-ethanolic extract (125, 250 and 500 mg/kg) of the stem bark of Chrysophyllum albidum and glibenclamide for 21 d on glucose level, serum enzyme markers for liver function, lipid profile, total protein, serum urea, serum creatinine, and body weight were evaluated in experimental diabetic rats administered with 45 mg/kg of streptozotocin. In vitro assays including glucose uptake in C2C12 cells and 3T3-L1 adipose tissues, α-glucosidase and α-amylase inhibition were employed to evaluate the possible mechanism of hypoglycemic action of the extract. DPPH and nitric oxide radical antioxidant activity of the extract was also measured. Results: The increased levels of blood glucose, triglycerides, low-density lipoprotein, total cholesterol, serum aspartate, and alanine transaminases, creatinine, and urea in the diabetic animals were reduced significantly (P<0.01) after treatment with Chrysophyllum albidum extract. The decreased total protein and high-density lipoprotein concentrations were normalized after treatment. In addition, the extract significantly (P<0.01) increased the transport of glucose in 3T3-L1 cells and C2C12 myotubes and exhibited considerable potential to inhibit α-amylase and α-glucosidase. It also demonstrated potent antioxidant action by scavenging considerably DPPH and nitric oxide radicals. Conclusions: Chrysophyllum albidum stem bark extract exhibits considerable antidiabetic effect by stimulating glucose uptake and utilization in C2C12 myotubes and 3T3-L1 adipocytes as well as inhibiting the activities of α-amylase and α-glucosidase.

Antidiabetic effect of Chrysophyllum albidum is mediated by enzyme inhibition and enhancement of glucose uptake via 3T3-L1 adipocytes and C2C12 myotubes

Objective: To investigate the in vivo and in vitro antidiabetic potential of Chrysophyllum albidum. Methods: The effects of oral treatment with hydro-ethanolic extract (125, 250 and 500 mg/kg) of the stem bark of Chrysophyllum albidum and glibenclamide for 21 d on glucose level, serum enzyme markers for liver function, lipid profile, total protein, serum urea, serum creatinine, and body weight were evaluated in experimental diabetic rats administered with 45 mg/kg of streptozotocin. In vitro assays including glucose uptake in C2C12 cells and 3T3-L1 adipose tissues, α-glucosidase and α-amylase inhibition were employed to evaluate the possible mechanism of hypoglycemic action of the extract. DPPH and nitric oxide radical antioxidant activity of the extract was also measured. Results: The increased levels of blood glucose, triglycerides, low-density lipoprotein, total cholesterol, serum aspartate, and alanine transaminases, creatinine, and urea in the diabetic animals were reduced significantly (P<0.01) after treatment with Chrysophyllum albidum extract. The decreased total protein and high-density lipoprotein concentrations were normalized after treatment. In addition, the extract significantly (P<0.01) increased the transport of glucose in 3T3-L1 cells and C2C12 myotubes and exhibited considerable potential to inhibit α-amylase and α-glucosidase. It also demonstrated potent antioxidant action by scavenging considerably DPPH and nitric oxide radicals. Conclusions: Chrysophyllum albidum stem bark extract exhibits considerable antidiabetic effect by stimulating glucose uptake and utilization in C2C12 myotubes and 3T3-L1 adipocytes as well as inhibiting the activities of α-amylase and α-glucosidase.

Study on quantification method of non-starch polysaccharides in Dendrobium catenatum / 中国中药杂志

The non-starch polysaccharides,mainly composed of glucomannans,are the major bioactive compounds in Dendrobium catenatum. In order to evaluate the quality of the medicinal materials and guide the production and processing,a quantification method of non-starch polysaccharides was established by stems of D. catenatum C15 strain collected from the pear epiphytic cultivation. The non-starch polysaccharides were obtained by " water extraction,α-amylase pretreatment,and alcohol precipitation once" method. The contents of starches,non-starch polysaccharides and monosaccharides were analyzed. In addition,the system suitability was tested. Compared with method of the Chinese Pharmacopoeia( 2015 edition),the contents of total polysaccharides,glucose,and mannose were decreased by 20. 9%,58. 8% and 1. 6% respectively. The method effectively digested starch and retained non-starch polysaccharides,and the analysis result was accurate and repeatable. Therefore,it is suitable for the content measurement of non-starch polysaccharides of D. catenatum. Furthermore,it could be an alternative method for quality control of D. catenatum and a reference in the determination of non-starch polysaccharides in other starch-containing medicinal materials.

Study on Inhibitory Effects of Ethanol Extract of Different Medicinal Parts from Syzygium jambos on the Activities of α- Glycosidase and α-Amylase / 中国药房

OBJECTIVE： To compare inhibitory effects of ethanol extract of different medicinal parts （root， stem， leaf， seed， flower and flesh） from Syzygium jambos on the activities of α-glycosidase and α-amylase. METHODS： Using half-inhibitory concentration value （IC50） as evaluation index， acarbose as positive control， inhibitory effects of ethanol extract of different medicinal parts from S. jambos on the activities of α-glycosidase （from yeast and small instestine in mice） and α-amylase were evaluated with in vitro inhibition model. The enzymatic dynamics and Lineweaver-Burk methods were used to analyze the inhibitory type of the best medicinal part on the activities of α-glycosidase and α-amylase. RESULTS： In the yeast α-glucosidase inhibitory activity test， the order of inhibitory activity was S. jambos seed＞S. jambos stem＞S. jambos leaf＞S. jambos root＞S. jambos flower＞S. jambos flesh＞acarbose. In the mice intestine α-glucosidase inhibitory activity test， the order of inhibitory activity was S. jambos seed＞S. jambos stem＞S. jambos root＞S. jambos leaf＞S. jambos flower＞S. jambos flesh＞acarbose. In the α-amylase inhibitory activity test， the order of inhibitory activity was acarbose＞S. jambos seed＞S. jambos stem＞S. jambos root＞S. jambos leaf＞S. jambos flesh＞S. jambos flower. Ethanol extract of S. jambos seed had the stronger inhibition activity against α-glucosidase from yeast，α-glucosidase from small intestine in mice and α-amylase than other medicinal parts [IC50 were（6.64±0.24）， （32.77±2.46） and （41.18±1.63） μg/mL]. Ethanol extract of S. jambos seed had the stronger inhibition activity against α-glucosidase than acarbose [IC50 to α-glucosidase from yeast and α-glucosidase from small intestine in mice were （2 833.33±5.48）， （1 304.21±6.45） μg/mL] （P＜0.05）. The inhibitory effect of ethanol extract from S. jambos on the activity of α-amylase was less than that of acarbose [IC50 was （27.27±1.24） μg/mL] （P＜0.05）. Enzymatic dynamics showed that the inhibitory type of ethanol extract from S. jambos seed on α-glucosidase and α-amylase were both reversible competitive inhibition. CONCLUSIONS： Among different parts of S. jambos such as root， stem， leaf， seed， flower and flesh， S. jambos seed shows the strongest inhibitory effects on the activities of α-glucosidase and α-amylase， which has the value of being developed for the treatment of diabetes or health food.

Inhibitory potentials of phenolic-rich extracts from Bridelia ferruginea on two key carbohydrate-metabolizing enzymes and Fe-induced pancreatic oxidative stress / 中西医结合学报

<p><b>OBJECTIVE</b>The current study was designed to evaluate the various antioxidant potentials and inhibitory effects of phenolic-rich leaf extracts of Bridelia ferruginea (BF) on the in vitro activities of some key enzymes involved in the metabolism of carbohydrates.</p><p><b>METHODS</b>In this study, BF leaf free and bound phenolic-rich extracts were used. We quantified total phenolic and flavonoid contents, and evaluated several antioxidant activities using assays for ferric reducing antioxidant power, total antioxidant activity (phosphomolybdenum reducing ability), 1,1-diphenyl-2-picrylhydrazyl and thiobarbituric acid reactive species. Also, extracts were tested for their ability to inhibit α-amylase and α-glucosidase activity.</p><p><b>RESULTS</b>The total phenolic and total flavonoid contents in the free phenolic extract of BF were significantly greater than in the bound phenolic extract. Also, all the antioxidant activities considered were significantly greater in the free phenolic extract than in the bound phenolic extract. In the same vein, the free phenolic-rich extract had a significantly higher percentage inhibition against α-glucosidase activity (IC = 28.5 µg/mL) than the bound phenolic extract (IC = 340.0 µg/mL). On the contrary, the free phenolic extract (IC = 210.0 µg/mL) had significantly lower inhibition against α-amylase than the bound phenolic-rich extract (IC = 190.0 µg/mL).</p><p><b>CONCLUSION</b>The phenolic-rich extracts of BF leaves showed antioxidant potentials and inhibited two key carbohydrate-metabolizing enzymes in vitro.</p>

Improving the thermostability of α-amylase from Rhizopus oryzae by rational design / 生物工程学报

Fungal α-amylases are widely used in the production of maltose syrup, while additional production costs may be required in the syrup production process due to the loss of enzyme activity, because of the poor thermostability exhibited in this type of enzyme. After deeply studying the importance of thermostability of fungal α-amylases applied in industrial production, with attempt to improve the thermostability of Rhizopus oryzae α-amylase (ROAmy), single-point mutations and combined mutations that based on analysis of B-factor values and molecular dynamics simulations were carried out for amino acid residues G128, K269 and G393 of ROAmy by overlapping PCR. The results showed that all the 7 mutants obtained presented better thermostability than the wild-type enzyme, and the best mutant was G128L/K269L/G393P which showed a 5.63-fold increase in half-life at 55 ℃ compared with the wild-type enzyme. Meanwhile, its optimum temperature increased from 50 ℃ to 65 ℃, the maximum reaction rate (Vmax) and catalytic efficiency (kcat/Km) increased by 65.38% and 99.86%. By comparing and analyzing the protein structure and function between the mutants and the wild-type enzyme, it was found that the increase of the number of hydrogen bonds or the introduction of proline in special position may be the main reasons for the improved thermostability that found in the mutants.

Production and application of α-amylase from indigenous fungalstrain Aspergillus luchuensis bs1

@#Aim:The study aimed at isolation, screening, optimization and partial purification of α-amylase and evaluating its desizing efficiency in textile industry. Methodology and results:The AF01 showed the highest α-amylase activity of 128 KU. This isolate was identified asAspergillus luchuensisstrain bs1 using 18S rRNA gene sequencing. The process parameters were screened by employing Plackett-Burman Design (PBD) with seven variables and followed by Box-Behnken Design with three positively influencing factors. The investigation revealed that the maximum α-amylase production (192KU) at medium pH 5.6, starch 3% (w/v) and sodium nitrate 0.5% (w/v). The partial purification of α-amylase was done by acetone precipitation and it resulted in 6.1 fold purification. Partially purified α-amylase recorded optimum activity at pH 5.5, 60 min of contact time, temperature stability at 60°C and 93%specificity to potato starch. The desized cotton fabric showed 9.5% weight loss, 5 sec of absorbency time and 8 rating in Tegewa analysis.Conclusion, significance and impact of study: The study proposes a novel indigenous fungal strain having ability to produce alpha amylase and an enzyme preparation for desizing sized cotton fabric in minimal concentration.

Selection and evaluation of calibrators for the conventional measurement system of serum α-Amylase / 临床检验杂志

Objective To select the calibrator for the conventional measurement system of serum a-Amylase (Amy).Methods The Amy levels of forty frozen serum samples were detected by the IFCC reference method (reference system),the conventional system A which used the Bioassay routine reagent and Randox calibrator,and was calibrated by the Roche PNPG7 method,and the conventional system B which used the Bioassay routine reagent and Randox calibrator,and was calibrated by the Rondox liquid stable PNPG7 method,respectively,and the acceptability of the two conventional systems was evaluated.Results The regression equations of the measurement values between the IFCC reference method and the conventional systems A and B were Y =0.964X +0.376 and Y =1.095X + 3.131,respectively.Among them,X and Y represented the results of the IFCC reference method and the conventional system,respectively.Compared with the IFCC reference method,the results of the conventional system A was reliable.Condusion With the guidance of the IFCC reference method,the domestic biochemical reagents matched with the suitable calibrators may provide the acceptable results.

Research progress in cortisol and α-amylase as stress biomarkers / 军事医学

We are facing increasing stress and challenges because of the fierce competition and fast pace of daily work and life.In other words,we are exposed to more frequent and intense social stress.Continual and intense stress is known to be detrimental to human well-being.Stress has been regarded as a major contributing factor of human diseases.There-fore,it′s necessary to review the recent research progress in stress biomarkers that are of different types,such as cortisol,α-amylase,catecholamine,heat shock protein and cytokines.In this review,we will focus on the most well reported stress biomarkers,including cortisol and α-amylase.We hope that this review will enable researchers and practitioners to gain in-sights into stress biomarkers,which will lead to improved healthcare decisions regarding prevention,treatment and rehabili-tation of stress-related diseases.

In vitro, in vivo and in silico anti-hyperglycemic inhibition by sinigrin

Objective To evaluate the anti-hyperglycemic potential of sinigrin using in vitro, in silico and in vivo streptozotocin (STZ) induced hyperglycemic zebrafish model. Methods The in vitro enzyme inhibition assay was carried out to determine the IC

In vitro, in vivo and in silico anti-hyperglycemic inhibition by sinigrin

OBJECTIVE@#To evaluate the anti-hyperglycemic potential of sinigrin using in vitro, in silico and in vivo streptozotocin (STZ) induced hyperglycemic zebrafish model.@*METHODS@#The in vitro enzyme inhibition assay was carried out to determine the IC value against α-glucosidase and α-amylase, in silico molecular docking was performed against both enzymes with PyRx tool and simulations were performed using GROMACS tool. Hyperglycemia was induced in zebrafishes using three intraperitoneal injections on alternating days for 1 week at 350 mg/kg of STZ. Hyperglycemic fishes were treated intraperitoneally with 50, 100 and 150 mg of sinigrin/kg of body weight for 24 h and glucose levels were measured.@*RESULTS@#The sinigrin showed very strong inhibition against α-glucosidase and α-amylase with 0.248 and 0.00124 μM while reference drug acarbose showed IC value of 73.0700 and 0.0017 μM against α-glucosidase and α-amylase, respectively. Kinetic analysis revealed that sinigrin has the mixed type mode of inhibition against α-glucosidase. Molecular docking results revealed its strong binding affinity with α-glucosidase (-10.00 kcal/mol) and α-amylase (-8.10 kcal/mol). Simulations graphs confirmed its stability against both enzymes. Furthermore, in hyperglycemic zebrafishes most significant (P < 0.001) reduction of glucose was occurred at 150 mg/kg, moderate significant reduction of glucose was observed at 100 mg/kg and no any significant reduction of glucose was measured at 50 mg/kg.@*CONCLUSIONS@#It can be evident from the present results that sinigrin has potent anti-hyperglycemic activity and it may prove to be effective treatment for the hyperglycemia.

Polyphenols isolated from Acacia mearnsii bark with anti-inflammatory and carbolytic enzyme inhibitory activities / 中国天然药物

The present study was designed to characterize the polyphenols isolated from Acacia mearnsii bark crude extract (B) and fractions (B1-B7) obtained by high-speed counter-current chromatography (HSCCC) and evaluate their anti-inflammatory and carbolytic enzymes (α-glucosidase and α-amylase) inhibitory activities. Fractions B4, B5, B6, B7 (total phenolics 850.3, 983.0, 843.9, and 572.5 mg·g, respectively; proanthocyanidins 75.7, 90.5, 95.0, and 44.8 mg·g, respectively) showed significant activities against reactive oxygen species (ROS), nitric oxide (NO) production, and expression of pro-inflammatory genes interleukin-1β (IL-1β) and inducible nitric oxide synthase (iNOS) in a lipopolysaccharide (LPS)-stimulated mouse macrophage cell line RAW 264.7. All the extracts suppressed α-glucosidase and α-amylase activities, two primary enzymes responsible for carbohydrate digestion. A. mearnsii bark samples possessed significantly stronger inhibitory effects against α-glucosidase enzyme (IC of 0.4-1.4 μg·mL) than the pharmaceutical acarbose (IC 141.8 μg·mL). B6 and B7 (IC 17.6 and 11.7 μg·mL, respectively) exhibited α-amylase inhibitory activity as efficacious as acarbose (IC 15.4 μg·mL). Moreover, B extract, at 25 µg·mL, significantly decreased the non-mitochondrial oxidative burst that is often associated with inflammatory response in human monocytic macrophages.

Inhibitory actions of Pseuderanthemum palatiferum (Nees) Radlk. Leaf ethanolic extract and its phytochemicals against carbohydrate-digesting enzymes

Objective: To investigate the effects of the leaf ethanolic extract of Pseuderanthemum palatiferum (PPE) and its isolated phytochemicals, stigmasterol and sitosterol-3-O-β-. d-glucopyranoside, against α-amylase and α-glucosidase enzyme activities both in vitro and in vivo. Methods: A concentration of maltose, which is a product released in α-amylase-catalyzing reaction, was used as an index of in vitro α-amylase activity. Meanwhile, in vitro α-glucosidase enzyme activity was indicated by the amount of liberated p-nitrophenol in α-glucosidase-catalyzing reaction. In vivo α-amylase and α-glucosidase enzyme activities were evaluated in the normal rats by using oral starch tolerance test and oral sucrose tolerance test, respectively. Results: PPE exerted a concentration-dependent inhibitory action against both α-amylase and α-glucosidase in vitro with the IC

Chemical constituents from leaves of Garcinia xanthochymus / 中国中药杂志

The constituents were isolated and purified by the silica gel and semi-preparative HPLC, and their structures were elucidated by NMR spectral and MS data. Fifteen compounds were isolated from the ethyl acetate fraction of 95% ethanol extract from the leaves of Garcinia xanthochymus, and identified as 5, 7, 4'-trihydroxy-6-(3-hydroxy-3-methylbutyl)-flavone(1), 1,5-dihydroxy-3-methoxyxanthone(2), 1, 3-dimethoxy-5-hydroxy xanthone(3), kaempferol(4),(2S,3S)-trans-dihydrokaempferol(5), 3, 24, 25-trihydroxytirucall-7-ene(6), 4-hydroxycinnamic acid(7), isovanillic acid(8),(Z)-2-(2,4-dihydroxy-2, 6, 6-trimethylcyclohexylidene)acetic acid(9), volkensiflavone(10), morelloflavone(11), 3, 8″-biapigenin(12), bilobetin(13), fukugiside(14), GB2a glucoside(15). Compound 1 is a new compound, compounds 5, 6, 9 and 13 are isolated from the genus Garcinia for the first time, and compounds 4, 7-8, 10-12, 14 and 15 are firstly found from this plant. α-Amylase inhibitory activities of 10 compounds were determined using starch azure as the substrate, and the results show that compound 13 has the inhibitory activities against α-amylase, IC₅₀ values of compound 13 and acarbose are 8.12, 4.32 μmol•L⁻¹ respectively.

Sex differences of salivary α-amylase activity, flow rate and pH value before and after acid stimulation / 第二军医大学学报

Objective To explore sex differences of salivary α-amylase activity (sAA), flow rate, pH value and correlation between sAA activity and flow rate. Methods Saliva samples were collected from 105 healthy volunteers before and after citric acid stimulation. Salivary sAA activity, flow rate and pH value were determined for each samples, and the correlation between sAA activity and flow rate was analyzed. The sex differences of the indices mentioned above were analyzed. Results Citric acid stimulation significantly increased salivary sAA activity, flow rate and pH value, with flow rate undergoing the greatest increase (P <0.01). No significant sex differences in sAA activity, flow rate or pH value were found at baseline, stimulation or acute responses (delta value) to citric acid stimulation. For female subjects, significant positive correlations were found between sAA activity and flow rate in unstimulated and stimulated saliva, between sAA activity delta value and flow rate delta value (P <0.05), and their coefficients kept relatively stable. For male subjects, significantly positive correlation was only found between stimulated sAA activity and flow rate (P <0.01). Conclusion Our study indicates that no sex difference in the sAA activity, flow rate or pH value at basal and acute responses to citric acid stimulation. However, certain sex difference is indicated in correlation between sAA activity and flow rate.

In vitro α-amylase inhibitory activity and in vivo hypoglycemic effect of methanol extract of Citrus macroptera Montr. fruit

Objective: To investigate the therapeutic effects of methanol extract of Citrus macroptera Montr. fruit in α-amylase inhibitory activity (in vitro) and hypoglycemic activity in normal and glucose induced hyperglycemic rats (in vivo). Methods: Fruits of Citrus macroptera without rind was extracted with pure methanol following cold extraction and tested for presence of phytochemical constituents, α-amylase inhibitory activity, and hypoglycemic effect in normal rats and glucose induced hyperglycemic rats.Results:showed that fruit extract had moderate α-amylase inhibitory activity [IC50 value=(3.638±0.190) mg/mL] as compared to acarbose. Moreover at 500 mg/kg and 1 000 mg/kg doses fruit extract significantly (P<0.05 and P<0.01 respectively) reduced fasting blood glucose level in normal rats as compared to glibenclamide (5 mg/kg). In oral glucose tolerance test, 500 mg/kg dose significantly reduced blood glucose level (P<0.05) at 2 h but 1000 mg/kg dose significantly reduced blood glucose level at 2 h and 3 h (P<0.05 and P<0.01 respectively) whereas glibenclamide (5 mg/kg) significantly reduced glucose level at every hour after administration. Overall time effect is also considered extremely significant with F value=23.83 and P value=0.0001 in oral glucose tolerance test.Conclusion:These findings suggest that the plant may be a potential source for the development Presence of saponin, steroid and terpenoid were identified in the extract. The results of new oral hypoglycemic agent.

Inhibitory effect of polyphenolic-rich extract from Cola nitida (Kolanut) seed on key enzyme linked to type 2 diabetes and Fe(2+) induced lipid peroxidation in rat pancreas in vitro

<p><b>OBJECTIVE</b>To investigate the inhibitory effect of phenolic-rich extracts from Cola nitida (C. nitida) seeds on key enzymes linked with type-2 diabetes and Fe(2+) induced oxidative stress in rat pancreas.</p><p><b>METHODS</b>The phenolic extract was prepared with 80% acetone (v/v). Subsequently, the antioxidant properties and inhibitory effect of the extract on α - amylase and α - glucosidase as well as on Fe(2+) induced lipid peroxidation in rat pancreas were determined in vitro.</p><p><b>RESULTS</b>The result revealed that C. nitida extract inhibited α-amylase (EC50=0.34 mg/mL) and α-glucosidase (EC50=0.32 mg/mL) activities as well as Fe(2+) induced lipid peroxidation in rat pancreas in a dose dependent manner. In addition, the extract had high DPPH radical scavenging ability (EC50=2.2 mg/mL) and reducing power (8.2 mg AAE/g). Characterization of the main phenolic compounds of the extract using gas chromatography analysis revealed catechin (6.6 mg/100 g), epicatechin (3.6 mg/100 g), apigenin (5.1 mg/100 g) and naringenin (3.6 mg/100 g) were the main compounds in the extract.</p><p><b>CONCLUSIONS</b>This antioxidant and enzyme inhibition could be some of the possible mechanism by which C. nitida is use in folklore for the management/treatment of type-2 diabetes. However, the enzyme inhibitory properties of the extract could be attributed to the presence of catechin, epicatechin, apigenin and naringenin.</p>