|Year : 2016 | Volume
| Issue : 1 | Page : 26-30
In vitro α-glucosidase and α-amylase inhibition by aqueous, hydroalcoholic, and alcoholic extract of Euphorbia hirta L.
Manjur Ali Sheliya1, Rayhana Begum1, Kolappa Krishna Pillai1, Vidhu Aeri2, Showkat Rasool Mir2, Abuzer Ali2, Manju Sharma1
1 Department of Pharmacology, Faculty of Pharmacy, Jamia Hamdard University, New Delhi, India
2 Department of Pharmacognosy and Phytochemistry, Faculty of Pharmacy, Jamia Hamdard University, New Delhi, India
|Date of Web Publication||13-Apr-2016|
Department of Pharmacology, Faculty of Pharmacy, Jamia Hamdard University, New Delhi - 110 062
Source of Support: None, Conflict of Interest: None
Background: Euphorbia hirta L. (Euphorbiaceae), commonly known as Dudhani, is distributed in the warm region of India and China. Traditionally, it is used in respiratory and gastrointestinal disorders. In addition, the antidiabetic property of the plant was also reported in the literature. This study was designed to evaluate the effect of aqueous, hydroalcoholic, and methanolic extracts (MEHs) of E. hirta on α-glucosidase and α-amylase in vitro. Materials and Methods: Aqueous, hydroalcoholic, and MEHs of E. hirta were prepared as per application program interface. In α-glucosidase activity, α-glucosidase (0.1 μ/mL) and substrate, 2.5 mM p-nitrophenyl-α-D-glucopyranoside was used; absorbance was recorded at 405 nm. In α-amylase activity, α-amylase solution (1.0 μ/mL) and substrate, 0.25% starch were used, and absorbance was measured at 540 nm. The IC50values were calculated by linear regression. Results: All the extracts showed α-glucosidase inhibitory activity comparable to acarbose with MEH having highest inhibitory activity among tested extracts. The observed IC50values were 213.63, 146.9, 78.88, and 8.07 μg/mL for aqueous, hydroalcoholic, MEH, and acarbose, respectively. All the extracts have shown mild α-amylase inhibitory activity compared to acarbose. Lineweaver–Burk plot has shown that the MEH is a mixed noncompetitive inhibitor for α-glucosidase enzyme. Conclusion: The results from this in vitro study clearly indicated that MEH of E. hirta had strong inhibitory activity against α-glucosidase and mild inhibitory activity against α-amylase. It can be used for management of postprandial hyperglycemia with lesser side effects, and provide a strong rationale for further animal and clinical studies.
Keywords: Euphorbia hirta, Euphorbiaceae, α-amylase, α-glucosidase
|How to cite this article:|
Sheliya MA, Begum R, Pillai KK, Aeri V, Mir SR, Ali A, Sharma M. In vitro α-glucosidase and α-amylase inhibition by aqueous, hydroalcoholic, and alcoholic extract of Euphorbia hirta L. Drug Dev Ther 2016;7:26-30
|How to cite this URL:|
Sheliya MA, Begum R, Pillai KK, Aeri V, Mir SR, Ali A, Sharma M. In vitro α-glucosidase and α-amylase inhibition by aqueous, hydroalcoholic, and alcoholic extract of Euphorbia hirta L. Drug Dev Ther [serial online] 2016 [cited 2017 May 27];7:26-30. Available from: http://www.ddtjournal.org/text.asp?2016/7/1/26/180156
| Introduction|| |
Diabetes mellitus (DM), a global public health problem, is now emerging as an epidemic worldwide. The world prevalence of diabetes among adults was 6.4%, affecting 285 million adults, in 2010, and will be increased to 7.7%, affecting 439 million adults by 2030. Among all cases of diabetes, approximately 90% are type II diabetes. Postprandial hyperglycemia (PPHG) is a more important risk factor in onset and the development of Type II diabetes. Dietary carbohydrates such as starch on hydrolysis yield glucose which is the prime source of glucose in PPHG. Dietary polysaccharides are hydrolyzed by α-amylase to oligosaccharides and disaccharides, which are further hydrolyzed to monosaccharides by α-glucosidases. Inhibition of α-glucosidase and α-amylase can significantly decrease PPHG and thus reduce the diabetes progression. In the past few decades, some synthetic α-glucosidase inhibitors, such as acarbose, miglitol, and voglibose, have been developed and have received considerable attention for the management of type II diabetes. Adverse effects such as abdominal distention, flatulence, meteorism, diarrhea, and pneumatosis cystoides intestinalis are common for these drugs., Such adverse effects might be caused by the excessive inhibition of pancreatic α-amylase resulting in the abnormal bacterial fermentation of undigested carbohydrates in the colon., The α-glucosidase inhibitors from plant sources are potential alternative to control PPHG. Lower inhibitory effect against α-amylase activity and stronger inhibition activity against α-glucosidase can be an ideal approach for the management of PPHG with minimal side effects.,Euphorbia hirta (Euphorbiaceae), commonly known as asthma weed, is often used in traditional medicine in many parts of Africa, America, Asia, Australia, and Pacific countries for the treatment of several ailments such as respiratory diseases, gastrointestinal disorders, skin diseases, diabetes, and kidney stones. Pharmacological activities such as antioxidant  and antidiabetic , have also been reported. Phytochemical investigation of this medicinal plant revealed the presence of several flavonoids , and polyphenols.
In the literature, the α-glucosidase inhibitory activity of E. hirta has been reported. However, the correlation between the presence of flavonoids and polyphenols to its activity has not been explored. Further in this study, type of inhibition is reported for the first time. Therefore, the objective of this research was to correlate in vitro α-glucosidase and α-amylase inhibitory activity of different extracts of E. hirta to their composition and to dwell the type of inhibition.
| Materials and Methods|| |
Chemicals and enzymes
α-glucosidase (EC 22.214.171.124), porcine pancreatic amylase (EC 126.96.36.199, type VI), quercetin, and gallic acid were purchased from Sigma–Aldrich (St. Louis, USA). Acarbose was obtained as a gift sample from Medley Pharmaceuticals Ltd., India. All chemicals and reagents used were of analytical grade.
E. hirta (whole plant) was collected from the garden of Maktabah Jafariyah Knowledge and Research Academy, India, geographically located on 23°58'12.5“N, 72°19.02'17”E in the month of May 2011. The plant material was authenticated by Dr. H. B. Singh, Scientist G and Head, Raw Materials, Herbarium and Museum, NISCAIR, New Delhi, India. The specimen was deposited there with the reference number Ref. NISCAIR/RHMD/Consult/2011-12/1785/85.
Preparation of extracts
The air dried and powdered sample (200 g) were separately extracted with water, methanol-water (1:1, v/v), and methanol by maceration for 24 h with occasional stirring. Extracts were filtered and concentrated under reduced pressure. The dry extracts were stored at 4°C until use.
Preliminary, the phytochemical analysis was carried out qualitatively. The quantitative estimation of total phenolic and total flavonoid contents (TFCs) was performed by Folin–Ciocalteu assay  and aluminum chloride assay, respectively.
In vitro α-glucosidase inhibition
The α-glucosidase inhibitory activity was measured by standard method. Briefly, 50 µL of sample and 50 µL of 0.1 M phosphate buffer (pH 6.8) containing α-glucosidase solution (0.1 µ/ml) was incubated at 37°C for 10 min. After, 50 µL of 2.5 mM p-nitrophenyl-α-D-glucopyranoside (PNPG) solution in the same buffer was added to each well and incubated for 20 min. Then, the reaction was stopped by adding 100 µL of 0.2 M Na2 CO3 and absorbance (A) was recorded at 405 nm by microplate reader (BioTek, USA) and compared to control, which had 50 µL of buffer solution in place of the extract.
In vitro α-amylase inhibition
The α-amylase inhibitory activity was measured by a standard method. The 50 µl of sample (0.020 M phosphate buffer, pH 6.9) was premixed with 100 µL of α-amylase solution (1.0 µ/mL in the pH 6.9 buffer), and incubated at 25°C for 10 min. After, 200 µL of a 0.25% starch solution was added to start the reaction for 5 min and terminated by addition of 1.0 mL of the DNS reagent. The test tubes were then kept on a boiling water bath for 5 min and cooled to room temperature, and absorbance was measured at 540 nm using a ultraviolet-visible spectrophotometer (Shimadzu, Japan). The control had 200 µL of buffer solution in place of the α-amylase solution.
The enzyme inhibitory activity was expressed as %inhibition and was calculated as follows:
Enzyme inhibitory activity (%) = (Acontrol – [Atest − Abackground])/Acontrol × 100
Where Acontrol, Atest, and Abackground are defined as the absorbance of 100% enzyme activity (only the solvent with the enzyme), test sample with the enzyme and test sample without the enzyme, respectively.
The concentration of inhibitors required for inhibiting 50% of the enzyme activity under the assay conditions was presented as the IC50 value.
Kinetic of α-glucosidase inhibition
Methanolic extract (MEH) was further analyzed for the type of inhibition. In this method, initial rates at different MEH concentration (0, 12.5, 25, 50, 100, and 200 µg/mL) were measured at different concentration of PNPG, substrate (0.075, 0.156, 0.313, 0.625, 1.25, 2.5, and 5.0 mM) in 0.1 M phosphate buffer containing α-glucosidase solution (0.1 µ/mL), pH 6.8 at 37°C, and release of p-nitrophenol was measured as described above. The inhibition pattern was evaluated by Lineweaver–Burk plot.
| Results|| |
Qualitative chemical tests have shown the presence of flavonoids, tannins, alkaloids, glycosides, steroids, terpenoids, and absence of proteins, saponins, sugars, and amino acid in MEH. Aqueous and hydroalcoholic extracts had shown similar chemical constituents. Quantitative estimation of total phenolic and TFCs was higher in MEH followed by hydroalcoholic and aqueous extract as showed in [Table 1].
|Table 1: Total phenolic and flavonoid content of Euphorbia hirta extracts|
Click here to view
In vitro α-glucosidase inhibition
All the extracts showed concentration-dependent inhibition of α-glucosidase [Figure 1]. The MEH showed highest α-glucosidase inhibition (75.18 ± 2.2) followed by acarbose (69.40 ± 3.8) and aqueous extract of E. hirta (AEH) (42.18 ± 2.9), respectively at their highest concentration tested. However, based on IC50 values, α-glucosidase inhibitory activity of MEH (78.88 µg/mL) was higher than that of acarbose (8.07 µg/mL), and lower than that of hydroalcoholic extract of E. hirta (HEH) (146.9 µg/mL) and AEH (213.63 µg/mL) [Table 2].
|Figure 1: α-glucosidase inhibitory activity of Euphorbia hirta and acarbose against α-glucosidase (0.1 μ/mL)|
Click here to view
|Table 2: Maximum inhibition of enzymes by Euphorbia hirta extracts and acarbose|
Click here to view
In vitro α-amylase inhibition
All the extracts and acarbose showed dose-dependent inhibition of α-amylase [Figure 2]. Interestingly, MEH showed weakest α-amylase enzyme inhibition (33.49 ± 3.6) followed by HEH (43.79 ± 2.5), AEH (46.89 ± 2.6), and acarbose (73.48 ± 2.7), respectively at their highest concentration tested [Figure 2]. Similarly, IC50 values of α-amylase inhibitory activity of MEH (280.71 µg/mL) was higher than that of HEH (202.24 µg/mL) and AEH (180.09 µg/mL), and acarbose (7.46 µg/mL) as summarized in [Table 2].
|Figure 2: α-amylase inhibitory activity of Euphorbia hirta and acarbose against α-amylase (1.0 μ/mL)|
Click here to view
Relationship between the α-glucosidase and α-amylase inhibition versus total phenolic content and total flavonoid content
The correlation coefficients (R2) of the highest α-glucosidase and α-amylase inhibition versus total phenolic content (TPC) and TFC in the aqueous, hydroalcoholic, and MEH of E. hirta were shown in [Figure 3]a and [Figure 3]b, respectively. The R2 value of the highest α-glucosidase inhibition versus TPC and TFC were 0.9872 and 0.956, respectively. Results suggested that a positive correlation. Similarly, the R2 value of the highest α-amylase inhibition versus TPC and TFC were 0.999 and 0.88, respectively, suggested that a negative correlation [Figure 3].
|Figure 3: Correlation coefficients (R2) of highest α-glucosidase and α-amylase inhibition versus total phenolic content (a) and total flavonoid content (b) in the aqueous, hydroalcoholic, and methanolic extracts of Euphorbia hirta|
Click here to view
Kinetics of α-glucosidase inhibition of methanolic extract
Lineweaver–Burk plot analysis of α-glucosidase inhibition by MEH showed that with increasing MEH concentration, the vertical axis intercept (1/VM) increased and the horizontal axis intercept (−1/KM) varied. These results indicate that the velocity of the reaction catalyzed by α-glucosidase was slowed down with increasing MEH concentration, and the KM value of α-glucosidase was also affected, which was correlated with the classical pattern of mixed noncompetitive inhibition [Figure 4].
|Figure 4: Lineweaver–Burk plot analysis of the inhibition kinetics of α-glucosidase inhibitory effects by methanolic extract of Euphorbia hirta|
Click here to view
Therefore, weak inhibitory effect against α-amylase activity and a stronger inhibition activity against α-glucosidase can be an ideal approach for the managing of PPHG. Flavonoids and phenolic compounds enriched extracts have shown high α-glucosidase inhibitory activity combined with low α-amylase inhibitory activity.,,
In this study, the inhibitory activity of aqueous, hydroalcoholic, and MEH of E. hirta upon α-glucosidase and α-amylase was elucidated and compared with acarbose. Further, the correlation between total phenolic and flavonoid content with α-glucosidase and α-amylase inhibition, and the type of α-glucosidase inhibition were also evaluated.
TPC and TFC estimation showed a high amount of polyphenols and flavonoids in MEH of E. hirta. The MEH exhibited strong α-glucosidase inhibition followed by acarbose, HEH, and AEH, respectively [Figure 1] and [Table 2]. In contrast, the α-amylase inhibitory activity was lowest in MEH compared to acarbose, HEH, and AEH [Figure 2] and [Table 2]. It might be due to the presence of high phenolic and flavonoid content as these inhibitions were perfectly correlated with total flavonoid and phenolic contents from the results [Figure 3]. It is evident that MEH was a strong inhibitor for α-glucosidase with mild α-amylase inhibitory activity. Moreover, MEH has showed the classical pattern of mixed noncompetitive inhibition for α-glucosidase further suggesting that MEH may bind close to the active site, or by binding elsewhere on enzyme site but has an influence on the active site.
| Discussion|| |
The results from this study clearly demonstrated that MEH of E. hirta had strong inhibitory activity against α-glucosidase and mild α-amylase inhibitory activity. It can be potentially useful to manage the glucose-induced hyperglycemia and provide the rationale for further phytochemical and preclinical studies. DM, a metabolic disorder with multiple etiologies, is characterized by chronic hyperglycemia with metabolic disturbances. Initial management of PPHG is of prime importance in the early prevention of diabetic complications, especially in type II diabetes. Acarbose is a competitive inhibitor of α-glucosidase as well as a mixed noncompetitive inhibitor of α-amylase. In this study, the inhibitory activity of aqueous, hydroalcoholic, and MEH of E. hirta upon α-glucosidase and α-amylase was elucidated and compared with acarbose. Further, the correlation between total phenolic and flavonoid content with α-glucosidase and α-amylase inhibition, and the type of α-glucosidase inhibition were also evaluated.
The first author is grateful for receiving financial support from University Grants Commission, New Delhi, India.
Financial support and sponsorship
University Grants Commission, New Delhi, India.
Conflicts of interest
There are no conflicts of interest.
| References|| |
Wild S, Roglic G, Green A, Sicree R, King H. Global prevalence of diabetes: Estimates for the year 2000 and projections for 2030. Diabetes Care 2004;27:1047-53.
Shaw JE, Sicree RA, Zimmet PZ. Global estimates of the prevalence of diabetes for 2010 and 2030. Diabetes Res Clin Pract 2010;87:4-14.
American Diabetes Association. Diagnosis and classification of diabetes mellitus. Diabetes Care 2005;28 Suppl 1:S37-42.
Dong HQ, Li M, Zhu F, Liu FL, Huang JB. Inhibitory potential of trilobatin from Lithocarpus polystachyus
Rehd against α-glucosidase and α-amylase linked to type 2 diabetes. Food Chem 2012;130:261-6.
Bischoff H, Puls W, Krause HP, Schutt H, Thomas G. Pharmacological properties of the novel glucosidase inhibitors BAY m1099 (miglitol) and BAY o 1248. Diabetes Res Clin Pract 1985;1:53-62.
Baron AD. Postprandial hyperglycaemia and alpha-glucosidase inhibitors. Diabetes Res Clin Pract 1998;40 Suppl:S51-5.
Toeller M. alpha-Glucosidase inhibitors in diabetes: Efficacy in NIDDM subjects. Eur J Clin Invest 1994;24 Suppl 3:31-5.
Puls W. Pharmacology of glucosidase inhibitors. In: Kuhlmann J, Puls W, editors. Oral Antidiabetics. Vol. 119. Berlin Heidelberg: Springer; 1996. p. 497-534.
Kojima K, Tsujimoto T, Fujii H, Morimoto T, Yoshioka S, Kato S, et al.
Pneumatosis cystoides intestinalis induced by the a-glucosidase inhibitor miglitol. Intern Med 2010;49:1545-8.
Horii S, Fukase H, Matsuo T, Kameda Y, Asano N, Matsui K. Synthesis and alpha-D-glucosidase inhibitory activity of N-substituted valiolamine derivatives as potential oral antidiabetic agents. J Med Chem 1986;29:1038-46.
Kwon YI, Vattem DA, Shetty K. Evaluation of clonal herbs of Lamiaceae
species for management of diabetes and hypertension. Asia Pac J Clin Nutr 2006;15:107-18.
Anonymous. Wealth of India, A dictionary of Indian Raw materials and Industrial Products. 1st
ed. New Delhi: National Institute of Science Communication and Information Resources (NISCAIR); 2005. p. 113-4.
Basma AA, Zakaria Z, Latha LY, Sasidharan S. Antioxidant activity and phytochemical screening of the methanol extracts of Euphorbia hirta
L. Asian Pac J Trop Med 2011;4:386-90.
Kumar S, Malhotra R, Kumar D. Antidiabetic and Free Radicals scavenging potential of Euphorbia hirta
Flower Extract. Indian J Pharm Sci 2010;72:533-7.
Widharna RM, Soemardji AA, Wirasutisna KR, Kardono LB. Anti diabetes mellitus activity in vivo
of ethanolic extr act and ethyl acetate fraction of Euphorbia hirta
L. Herb. Int J Pharmacol 2010;6:231-40.
Subbiah V. Inventor Anti-Inflammatory Properties of a Standardized Extract from Euphorbia hirta
51) ACTIVIty and for Treating Conditions of Inflammation. USA; 2007.
Wu Y, Qu W, Geng D, Liang JY, Luo YL. Phenols and flavonoids from the aerial part of Euphorbia hirta
. Chin J Nat Med 2012;10:40-2.
Yoshida T, Chen L, Shingu T, Okuda T. Euphorbins A and B, novel dimericdehydroellagitannins from Euphorbia hirta
L. Chem Pharm Bull 1988;36:2940-9.
Ali M. Text Book of Pharmacognosy. New Delhi: CBS Publisher; p. 112-4.
Ainsworth EA, Gillespie KM. Estimation of total phenolic content and other oxidation substrates in plant tissues using Folin-Ciocalteu reagent. Nat Protoc 2007;2:875-7.
Chang CC, Yang M, Wen H, Chern J. Estimation of total flavonoid content in propolis by two complementary colorimetric methods. J Food Drug Anal 2002;10:178-82.
Bhandari MR, Jong-Anurakkun N, Hong G, Kawabata J. α-Glucosidase and α-amylase inhibitory activities of Nepalese medicinal herb Pakhanbhed (Bergenia ciliata
, Haw.). Food Chem 2008;106:247-52.
Shobana S, Sreerama YN, Malleshi NG. Composition and enzyme inhibitory properties of finger millet (Eleusine coracana
L.) seed coat phenolics: Mode of inhibition of α-glucosidase and pancreatic amylase. Food Chem 2009;115:1268-73.
Copeland RA. Enzymes: A Practical Introduction to Structure, Mechanism, and Data Analysis. VCH Publishers; 1996.
Puavilai G, Chanprasertyotin S, Sriphrapradaeng A. Diagnostic criteria for diabetes mellitus and other categories of glucose intolerance: 1997 criteria by the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus (ADA), 1998 WHO consultation criteria, and 1985 WHO criteria. World Health Organization. Diabetes Res Clin Pract 1999;44:21-6.
Ratner RE. Controlling postprandial hyperglycemia. Am J Cardiol 2001 20;88 (6A):26H-31H.
Kim MJ, Lee SB, Lee HS, Lee SY, Baek JS, Kim D, et al.
Comparative study of the inhibition of alpha-glucosidase, alpha-amylase, and cyclomaltodextrin glucanosyltransferase by acarbose, isoacarbose, and acarviosine-glucose. Arch Biochem Biophys 1999;371:277-83.
[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2]