Evaluation Of Α-glucosidase Inhibitory Activity Research Articles

α-Glucosidase Inhibitory Phytochemical Components of Chinese Endemic Plant Whitfordiodendron filipes var. tomentosum.

Whitfordiodendron filipes var. tomentosum is an endemic plant in China. There have been no chemical or pharmacological studies of this plant reported before. In the current research, eight triterpenes and two steroids were obtained. Their structures were established by the analysis of NMR data and comparison with those reported in the literature. These ten structurally diverse compounds comprised five distinct carbon frameworks with different functionalities. The chemotaxonomic significance of these secondary metabolites was discussed, disclosing the common components between the variant W. filipes var. tomentosum and the species W. filipe. Evaluation of α-glucosidase inhibitory activities of these isolates disclosed that compounds 1, 2, 4, and 6 exhibited significant α-glucosidase inhibitory activities (IC50 = 16.6-19.2 μM), which were close in value to the positive control acarbose (IC50 = 11.5 μM). Moreover, the binding modes between the biologically active compounds 1, 2, 4, and 6 and the α-glucosidase protein were preliminarily studied using molecular docking. This study not only showed the chemical and biological profile of the plant W. filipes var. tomentosum but also revealed that these components could be developed as hypoglycemic lead compounds.

Extraction and evaluation of α-glucosidase inhibitory activity of polysaccharide from Urena lobata L. roots

Polysaccharides are compounds found in the roots of Urena lobata L. Polysaccharides are of interest due to many valuable biological activities such as immunomodulatory, anti-cancer, diabetes treatment, anti-inflammatory and antioxidant. In this research, polysaccharides extracted from Urena lobata L. roots were analyzed by GC-MS (Gas Chromatography Mass Spectometry) and GPC (Gel Permeation Chromatography). The results show that the polysaccharide from Urena lobata L. natural roots is a heteropolysaccharide. This polysaccharide has two peaks with the weighted average molecular weights (Mw) as 1.823 x 107 g/mol and 1.139 x 105 g/mol. The monosaccharide composition of this polysaccharide includes rhamnose, arabinose, xyloza, mannose, glucose and galactose with the composition ratios of 13.927, 16.579, 3.174, 5.442, 27.659 and 33.219% respectively. In addition, when investigating the α-glucosidase inhibitory activity of polysaccharide from three types of Urena lobata L. roots cultured under different conditions: natural, in vitro and aeroponics, the results showed that the activity of in vitro hairy root polysaccharide was the best. This shows the potential for the development of biologically active polysaccharide sources by in vitro hairy root culture of Urena lobata L.

Evaluation of alpha-glucosidase inhibition activity and glycosides in the Syringa pubescens Turcz from different geographical origin

Inhibition of α-glucosidase is an attractive strategy for the control of hyperglycaemia. Naturally occurring bioactive compounds are potential sources of α-glucosidase inhibitors. The Syringa pubescens Turcz (SP) is commonly used as Chinese folk medicine for treatment of hepatitis and cirrhosis. However, the anti-hyperglycemic activity of SP was lack of study and the report on compounds of α-glucosidase inhibitory activity of SP was also insufficient. In this study, the α-glucosidase inhibitory activity of SP extract was firstly assessed in vitro. The quantification analysis of bioactive glycosides in SP collected at different geographical origins and its correlation with α-glucosidase inhibitory activities were investigated. As the results, six glycosides including salidroside, echinacoisde, forsythoside B, verbascoside, isoacteoside and oleuropein were simultaneously determined using HPLC-DAD method. Moreover, SP collected from different geographical origins exhibited different concentrations of bioactive glycosides and had potential α-glucosidase inhibitory activity. The results of correlation analysis indicated that the amounts of glycosides were positively correlated with the α-glucosidase inhibitory activities of SP. Then, the evaluation of α-glucosidase inhibitory activity of six glycosides was performed. And docking study was conducted to predict the possible binding sites of forsythoside B. Forsythoside B might be the most possible α-glucosidase inhibitor in SP.

Isolation, selection and evaluation of α-glucosidase inhibitory activity from endophytic Streptomyces sp. isolated from Citrus myrtifolia cultivar in Hoa Binh, Vietnam

Cao Phong orange (Citrus sinensis Lour) was grown in Cao Phong district, Hoa Binh province. Citrus sinensis is Vietnam’s most valued commercial fruit. In this study, 30 microorganim strains were isolated from the samples of root, stem, and leaf of Cao Phong orange. The ratio of endophytic actinomycetes was found in different parts of the plant: root, stem, and leaf was 37%, 40%, and 23%, respectively. The isolating HBC6-2 was selected because of its high output of α-glucosidase inhibitors from 6 different strains. Morphological, physiological, and biochemical characterization showed that HBC6-2 strain belongs to the Streptomyces sp. The 16S rRNA sequence of HBC6-2 indicated 99% identity to the corresponding sequence of Streptomyces costaricanus, and was registered on GenBank with the code MT 453944.1.
 Streptomyces costaricanus EBL.HB6 was able to produce melanin yelow pigment, and its aerial and substrate mycelia have brown and yellow-grey pigment on ISP2, ISP3, ISP4, and ISP5 cultivating medium, respectively. The optimal pH range was from 5-10 and temperature from 15-40°C and exhibited salt tolerance up to 3% and utilized the carbon sources such as fructose, xylose, arabinose, cellulose, and rhamnose. In the following investigation, Streptomyces costaricanus EBL.HB6 displayed the highest α-glucosidase inhibitory activity by 68.98% among Streptomyces sp. strains

Investigation of factors in improving Agrobacterium-mediated gene transfer in Ruellia tuberosa L. and evaluation of α-glucosidase inhibitory activity in established hairy roots

Ruellia tuberosa (family Acanthaceae) is widely known in traditional medicine in Asian countries for the treatment of diabetes and other diseases. Its roots were demonstrated to possess a hypoglycemic ability in diabetic animal models. In this study, an original induced procedure was investigated to establish hairy root (HR) from R. tuberosa. With the aim of increasing the transformation rate, some induced factors (acetosyringone (AS) dosage, type of explant, age, infection time, bacterial density, co-cultivation duration) were individually examined. As a result, an improved procedure was implemented: ten-day-old in vitro cotyledon explants were injured and then immersed in the bacterial suspension (OD600 nm = 0.4) added 200 µM AS during 10 min. The infected explants were co-cultivated for 4 days in the Murashige & Skoog (MS) medium before transferring to the medium containing cefotaxime for bacterial elimination. After thirty days of culture, the improved procedure revealed a synergistic effect by enhancing the rooting rate and number of secondary roots per explant up to 4.4- and 8.0-fold, respectively, in comparison with the original procedure. The R. tuberosa HR was then cultured in liquid MS medium and achieved the highest biomass production at the late exponential growth phase (3rd week). Its ethanol extract was also higher 2.0-fold in α-glucosidase inhibitory activity than that of the natural root. In conclusion, the α-glucosidase inhibitory activity of HR inducing by the improved procedure may offer an effective and reliable substitute for the utilization of this herbal plant.

Isolation of acid tolerant lactic acid bacteria and evaluation of α-glucosidase inhibitory activity

In this study, lactic acid bacteria strains (LABs) were isolated from Korean traditional fermented food and examined as potential probiotics using in vitro methods. Ten LAB strains survived in de Man, Rogosa and Sharpe broth adjusted to pH 2.5 were tested for resistance to acidic conditions and bile, antimicrobial activity, and α-glucosidase inhibitory activity. Among them, strain MBEL1397 showed antimicrobial activity against Bacillus cereus and exhibited survival rates of over 97% in acidic and bile conditions. The α-glucosidase inhibitory activity was 3.91 ± 0.25%, corresponding to approximately 2.3 times higher than that of acarbose. MBEL1397 was susceptible to ampicillin, erythromycin, and penicillin G and identified as Lactobacillus sakei. It was deposited to Korean Collection for Type Culture (KCTC) as KCTC14037BP. In conclusion, these results demonstrate that L. sakei MBEL1397 might be prominent probiotics with potential hypoglycemic effects.

Study on α-glucosidase enzyme inhibitory activity and DPPH free radical scavenging of green coffee bean extract (Coffea canephora)

Abstract: α-glucosidase enzyme is one of the important molecular targets in the treatment of diabetes. In addition, free radicals are the cause of insulin resistance, damage β- cell pancreatic, glucose uptake disorders and induced diabetes. In this study we evaluated the inhibitory effect of α-glucosidase enzyme and antioxidant effect by using DPPH free radical scavenging method of green coffee bean extract (Coffea canephora) and its fractions. Coffee beans were pulverized, extracted with ethanol 70% by sonications, and fractionated with n-hexane, ethyl acetate (EtOAc) and n-butanol (n-BuOH) solvents. Our results showed that coffee bean extract has a strong α-glucosidase enzyme inhibitory activity, especially EtOAc fraction with an IC50 value of 2.21 ± 0.04 µg/mL. Furthermore, the coffee bean extract has an antioxidant effect by DPPH radical scavenging ability, and EtOAc fraction has the highest effect with an IC50 value of 25.69 ± 3.08 µg/ml. Our results show that green coffee beans and EtOAc fraction have potential effect in preventing and supporting for the treatment of diabetes.
 Keywords
 Coffee; Coffea canephora; free radical; α-glucosidase; DPPH.
 References
 [1] Federation ID. IDF Diabetes Atlas 8th Edition (2017).[2] Wright Jr E, Scism‐Bacon J, Glass L. Oxidative stress in type 2 diabetes: the role of fasting and postprandial glycaemia. International journal of clinical practice 60(3) (2006) 308.[3] X. Chen. A review on coffee leaves: Phytochemicals, bioactivities and applications. Critical reviews in food science and nutrition 59(6) (2019) 1008.[4] Chu Y-F. Coffee: emerging health effects and disease prevention. John Wiley & Sons (2012).[5] N.T. Hai, D.K. Thu, B.T. Tung. Sarcandra glabra Extract Protects against Scopolamine Induced Cognitive Deficits by Modulating Neuroinflammation and the Cholinergic System. Current Enzyme Inhibition 14(3) (2018) 210.[6] B.T. Tung, D.K. Thu, P.T. Hai, N.T. Hai. Evaluation of α-glucosidase inhibitory activity of fractions from Punica granatum Linn fruits (in Vietnamese), Journal of Traditional Vietnamese Medicine and Pharmacy 5(18) (2018) 59.[7] S. Lenzen. The mechanisms of alloxan-and streptozotocin-induced diabetes. Diabetologia 51(2) (2008) 216.[8] K. Shapiro, W.C. Gong . Natural products used for diabetes. Journal of the American Pharmaceutical Association 42(2) (2002) 217.[9] O. Babova, A. Occhipinti, M.E. Maffei. Chemical partitioning and antioxidant capacity of green coffee (Coffea arabica and Coffea canephora) of different geographical origin. Phytochemistry 123 (2016) 33.[10] A. Priftis, D. Stagos, K. Konstantinopoulos, C. Tsitsimpikou, D.A. Spandidos, A.M. Tsatsakis, et al. Comparison of antioxidant activity between green and roasted coffee beans using molecular methods. Molecular medicine reports 12(5) (2015) 7293.[11] N. Liang, D.D. Kitts. Antioxidant property of coffee components: assessment of methods that define mechanisms of action. Molecules 19(11) (2014) 19180.[12] Vieira TMFdS. Potential antioxidant of brazilian coffee from the region of Cerrado. Food Science and Technology 38(3) (2018) 447.[13] S.D. Kim. α-Glucosidase inhibitor isolated from coffee. J Microbiol Biotechnol 25(2) (2015) 174.[14] Y. Zheng, K. Liu, G. Jia, H. Li, L. Han, Y. Kimura Effect of hot-water extract of coffee seeds on postprandial blood glucose concentration in rats. (2007).
 

A New Glycoside and in vitro Evalution of α-Glucosidase Inhibitory Activity of Constituents of the Mangrove Lumnitzera racemosa

From Lumnitzera racemosa Willd., a new glycoside, 2- O-galloyl-α-L-rhamnopyranosyl-(3→4’)-3’- O-galloyl-α-L-rhamnopyranose (1), as well as nine known compounds were isolated. Their chemical structures were elucidated by spectroscopic data analysis as well as comparison with the ones in the literature. The evaluation of α-glucosidase inhibitory activity of the extracts and some isolated compounds was measured.

Organocatalyzed solvent free an efficient novel synthesis of 2,4,5-trisubstituted imidazoles for α-glucosidase inhibition to treat diabetes

A new and efficient solvent free synthesis of 2,4,5-trisubstituted imidazoles (3a–3j) was achieved by N-acetyl glycine (NAG) catalyzed three components condensation of aldehydes, benzil and ammonium acetate. Our synthetic methodology accommodated a range of various substituted alkyl and aryl aldehydes. Evaluation of α-glucosidase inhibitory activity of these imidazole derivatives revealed that most of them presented good α-glucosidase inhibition at low micro-molar concentrations. Among the synthesized compounds, compound 3c, bearing the ortho-hydroxy phenyl substituent at position 2 displayed the highest inhibitory activity with an IC50 value 74.32±0.59μM. In silico molecular docking for all compounds and computational studies of the most active compound 3c were also performed.

A new triterpenoid saponin from Glinus oppositifolius with α-glucosidase inhibitory activity

Evaluation of α-glucosidase inhibitory activity led to the isolation of six triterpene saponins from the aerial parts of Glinus oppositifolius including one new and five known constituents. The structure of the new saponin, glinoside C (1), was established as 16-O-(β-D-glucopyranosyl)-3β,12β,16β,21α,22-pentahydroxy hopane by extensive use of 1-D, 2-D NMR and mass spectral techniques. The other constituents identified were 3-O-(β-D-xylopyranosyl)-spergulagenin A (2), spergulacin (3), spergulin A (4), spergulacin A (5) and spergulin B (6). Compound 1 exhibited the greatest inhibition of the enzyme with IC50 of 127 ± 30 µM. Kinetics study for the compound 1 demonstrated mixed type of inhibition (Ki = 157.9 µM).

Quantitative analysis of neosalacinol and neokotalanol, another two potent α-glucosidase inhibitors from Salacia species, by LC-MS with ion pair chromatography

A quantitative analytical method for the highly polar sulfonium pseudo-sugar constituents neosalacinol (3) and neokotalanol (4), another two potent α-glucosidase inhibitors isolated from Ayurvedic traditional medicine Salacia species, was developed by employing an ion pair reagent upon chromatographic separation. The optimum conditions for separation and detection of these two constituents were achieved on an ODS column (3-µm particle size, 2.1-mm i.d.×100mm) with 5mM undecafluorohexanoic acid-MeOH (99:1, v/v) as the mobile phase and using MS equipped with an electrospray ionization source. More than ten samples of Salacia from different origins were analyzed, and the results indicated that the assay was reproducible and precise and could be readily utilized for evaluation of α-glucosidase inhibitory activity of Salacia species. By combining this assay with the quantitative analytical method previously developed for salacinol (1) and kotalanol (2), a more precise and strict evaluation of α-glucosidase inhibitory activities of extracts from Salacia species (R=0.959 for maltase and 0.795 for sucrase) was achieved.