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Screening for potential α-glucosidase and α-amylase inhibitory constituents from selected Vietnamese plants used to treat type 2 diabetes.
J Ethnopharmacol. 2016 Jun 20; 186:189-195.JE

Abstract

ETHNOPHARMACOLOGICAL RELEVANCE

The 18 plant species investigated in this study have been used as herbal antidiabetic remedies in Vietnamese traditional medicines. This study aimed to evaluate their ability to inhibit α-glucosidase and α-amylase, two key enzymes involved in serum glucose regulation.

MATERIALS AND METHODS

Chloroform, ethanol and water extracts of 18 plants were screened for α-glucosidase and α-amylase inhibitory activity. Analytical-scale HPLC was subsequently used to investigate the most active extracts, where samples with low level of tannins were identified and fractionated into 96-well microplates, followed by α-glucosidase and α-amylase assessment of each well. High-resolution α-glucosidase and α-amylase inhibition profiles constructed from these assays allowed identification of HPLC peaks correlated with α-glucosidase and α-amylase inhibitory activity. The active constituents were subsequently isolated using preparative-scale HPLC and their structure was elucidated by HR-ESIMS and NMR.

RESULTS

Ethanol extracts of Nepenthes mirabilis, Phyllanthus urinaria, and Kandelia candel significantly inhibited α-glucosidase with IC50 values of 32.7±6.3, 39.7±9.7, and 35.4±13.9μg/mL, respectively. Water extracts of N. mirabilis, Phyllanthus amarus, P. urinaria, Lagerstroemia speciosa, Syzygium cumini, Rhizophora mucronata, and K. candel showed IC50 values of 3.3±0.8, 34.9±1.5, 14.6±4.6, 5.4±0.5, 20.9±1.8, 3.3±0.6, and 4.0±0.8μg/mL, respectively. In the α-amylase inhibition assay, ethanol extracts of K. candel and Ficus racemosa showed IC50 of 7.6±0.9 and 46.7±23.6μg/mL, respectively. Showing low tannin constituents as seen from HPLC profiles, P. amarus and P. urinaria water extracts and F. racemosa ethanol extract were subjected to microfractionation. Only high-resolution α-glucosidase inhibition profiles of P. amarus and P. urinaria water extracts showed several active compounds, which were isolated and identified as corilagin (1), repandusinic acid A (2), and mallotinin (3). IC50 of these compounds were 1.70±0.03, 6.10±0.10, and 3.76±0.15μM, respectively. Kinetics analysis revealed that 1 displayed a mixed type mode of inhibition with Ki and Ki' values of 2.37±0.90 and 2.61±0.61μM, respectively, whereas 2 and 3 competitively inhibited α-glucosidase with Ki values of 4.01±0.47 and 0.65±0.11μM, respectively.

CONCLUSION

Corilagin (1), repandusinic acid A (2), and mallotinin (3) were potent α-glucosidase inhibitors contributing significantly to the inhibitory effect observed for the water extracts of P. amarus and P. urinaria.

Authors+Show Affiliations

Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark.Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark.Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark. Electronic address: anna.jager@sund.ku.dk.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

27041401

Citation

Trinh, Binh T D., et al. "Screening for Potential Α-glucosidase and Α-amylase Inhibitory Constituents From Selected Vietnamese Plants Used to Treat Type 2 Diabetes." Journal of Ethnopharmacology, vol. 186, 2016, pp. 189-195.
Trinh BTD, Staerk D, Jäger AK. Screening for potential α-glucosidase and α-amylase inhibitory constituents from selected Vietnamese plants used to treat type 2 diabetes. J Ethnopharmacol. 2016;186:189-195.
Trinh, B. T. D., Staerk, D., & Jäger, A. K. (2016). Screening for potential α-glucosidase and α-amylase inhibitory constituents from selected Vietnamese plants used to treat type 2 diabetes. Journal of Ethnopharmacology, 186, 189-195. https://doi.org/10.1016/j.jep.2016.03.060
Trinh BTD, Staerk D, Jäger AK. Screening for Potential Α-glucosidase and Α-amylase Inhibitory Constituents From Selected Vietnamese Plants Used to Treat Type 2 Diabetes. J Ethnopharmacol. 2016 Jun 20;186:189-195. PubMed PMID: 27041401.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Screening for potential α-glucosidase and α-amylase inhibitory constituents from selected Vietnamese plants used to treat type 2 diabetes. AU - Trinh,Binh T D, AU - Staerk,Dan, AU - Jäger,Anna K, Y1 - 2016/03/31/ PY - 2015/11/11/received PY - 2016/03/29/revised PY - 2016/03/30/accepted PY - 2016/4/5/entrez PY - 2016/4/5/pubmed PY - 2017/2/23/medline KW - High-resolution inhibition profile KW - Phyllanthus KW - Type 2 diabetes KW - Vietnamese plants KW - α-amylase KW - α-glucosidase SP - 189 EP - 195 JF - Journal of ethnopharmacology JO - J Ethnopharmacol VL - 186 N2 - ETHNOPHARMACOLOGICAL RELEVANCE: The 18 plant species investigated in this study have been used as herbal antidiabetic remedies in Vietnamese traditional medicines. This study aimed to evaluate their ability to inhibit α-glucosidase and α-amylase, two key enzymes involved in serum glucose regulation. MATERIALS AND METHODS: Chloroform, ethanol and water extracts of 18 plants were screened for α-glucosidase and α-amylase inhibitory activity. Analytical-scale HPLC was subsequently used to investigate the most active extracts, where samples with low level of tannins were identified and fractionated into 96-well microplates, followed by α-glucosidase and α-amylase assessment of each well. High-resolution α-glucosidase and α-amylase inhibition profiles constructed from these assays allowed identification of HPLC peaks correlated with α-glucosidase and α-amylase inhibitory activity. The active constituents were subsequently isolated using preparative-scale HPLC and their structure was elucidated by HR-ESIMS and NMR. RESULTS: Ethanol extracts of Nepenthes mirabilis, Phyllanthus urinaria, and Kandelia candel significantly inhibited α-glucosidase with IC50 values of 32.7±6.3, 39.7±9.7, and 35.4±13.9μg/mL, respectively. Water extracts of N. mirabilis, Phyllanthus amarus, P. urinaria, Lagerstroemia speciosa, Syzygium cumini, Rhizophora mucronata, and K. candel showed IC50 values of 3.3±0.8, 34.9±1.5, 14.6±4.6, 5.4±0.5, 20.9±1.8, 3.3±0.6, and 4.0±0.8μg/mL, respectively. In the α-amylase inhibition assay, ethanol extracts of K. candel and Ficus racemosa showed IC50 of 7.6±0.9 and 46.7±23.6μg/mL, respectively. Showing low tannin constituents as seen from HPLC profiles, P. amarus and P. urinaria water extracts and F. racemosa ethanol extract were subjected to microfractionation. Only high-resolution α-glucosidase inhibition profiles of P. amarus and P. urinaria water extracts showed several active compounds, which were isolated and identified as corilagin (1), repandusinic acid A (2), and mallotinin (3). IC50 of these compounds were 1.70±0.03, 6.10±0.10, and 3.76±0.15μM, respectively. Kinetics analysis revealed that 1 displayed a mixed type mode of inhibition with Ki and Ki' values of 2.37±0.90 and 2.61±0.61μM, respectively, whereas 2 and 3 competitively inhibited α-glucosidase with Ki values of 4.01±0.47 and 0.65±0.11μM, respectively. CONCLUSION: Corilagin (1), repandusinic acid A (2), and mallotinin (3) were potent α-glucosidase inhibitors contributing significantly to the inhibitory effect observed for the water extracts of P. amarus and P. urinaria. SN - 1872-7573 UR - https://www.unboundmedicine.com/medline/citation/27041401/Screening_for_potential_α_glucosidase_and_α_amylase_inhibitory_constituents_from_selected_Vietnamese_plants_used_to_treat_type_2_diabetes_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0378-8741(16)30174-X DB - PRIME DP - Unbound Medicine ER -