Determination of total flavonoids content in buckwheat and inhibition of α-amylase activity

Abstract

Diabetes is one of the most difficult chronic diseases to cure in the world, which seriously affects people’s health and quality of life. Flavonoids in buckwheat can regulate blood glucose levels by inhibiting α-amylase activity. Therefore, sweet buckwheat produced in Inner Mongolia was used as the research object, and buckwheat flavonoids were extracted by ultrasonic-assisted extraction method. Total flavonoids content was determined by ultraviolet-visible spectrophotometry. With acarbose as the positive control, the inhibition test of α-amylase was carried out by DNS colorimetry to study the inhibition behavior of flavonoids on α-amylase activity. The results showed that the extraction process of flavonoids was stable and reliable, and the established method for the determination of flavonoids was simple, accurate and reproducible. The total flavonoids content of buckwheat samples was 2.706 mg/g, buckwheat total flavonoids extraction solution had an inhibitory effect on α-amylase, and its median inhibition concentration (IC₅₀) was 38.53 mg/mL. The results of this experiment provide a technical reference for the development and utilization of flavonoids in Inner Mongolia sweet buckwheat, and provide a theoretical reference for the development and application of flavonoid-rich hypoglycemic food.

Keywords

buckwheat / total flavonoids content / α-amylase / activity inhibition

References

[1] Zheng B, Zhang H, Wang L, et al. Characterization of 16-kDa major allergen with α-amylase inhibitor domain in tartary buckwheat seeds[J]. Molecular Immunology, 2018, 94: 121-130.

[2] Skrabanja V, et al. Liljeberg Elmsthl Helena G, Kreft I, Nutritional properties of starch in buckwheat products: studies in vitro and in vivo[J]. Journal of Agricultural and Food Chemistry, 2001, 49 (1): 490-496.

[3] Wang MT, Shi JY, Wang L, et al. Inhibitory kinetics and mechanism of flavonoids from lotus (Nelumbo nucifera Gaertn.) leaf against pancreatic α-amylase[J]. International Journal of Biological Macromolecules, 2018, 120 (Pt B): 2589-2596.

[4] Thanh MT, MinhHoang P, Thi TT, et al. Discovery of novel flavonoid derivatives as potential dual inhibitors against α-glucosidase and α-amylase: Virtual screening, synthesis, and biological evaluation[J]. Molecular Diversity, 2024, 28 (3): 1629-1650.

[5] Vang T, Bottini N, Cucca F, et al. Role of PTPN22 in type 1 diabetes and other autoimmune diseases[J]. Seminars in Immunology, 2006, 18 (4): 207-213.

[6] Lam TP, Tran NVN, Pham LHD, et al. Flavonoids as dual- target inhibitors against α-glucosidase and α-amylase: A systematic review of in vitro studies[J]. Natural Products and Bioprospecting, 2024, 14 (1): 4.

[7] Hassan R, Mohammad-Bagher H-GS, Hadi A, et al. Differential α-amylase/α-glucosidase inhibitory activities of plant-derived phenolic compounds: A virtual screening perspective for the treatment of obesity and diabetes[J]. Food & Function, 2017, 8 (5): 1942-1954.

[8] Siddhu N, Saxena J. Quantification of total phenolic and total flavonoid content of extracts of tagetes Erecta flowers[J]. Asian Journal of Pharmaceutical and Clinical Research, 2017, 10 (6): 328-330.

[9] Zhang HL, Wu QX, Qin XM. Camellia nitidissima Chi flower extracts inhibit α-amylase and α-glucosidase: In vitro by analysis of optimization of addition methods, inhibitory kinetics and mechanisms[J]. Process Biochemistry, 2019, 86: 177-185.

[10] Jiang P, Burczynski F, Campbell C, et al. Rutin and flavonoid contents in three buckwheat species Fagopyrum esculentum, F. tataricum, and F. homotropicum and their protective effects against lipid peroxidation[J]. Food Research International, 2006, 40 (3): 356-364.

[11] Davis AB, Hoseney RC. Grain sorghum condensed tannins. I. Isolation, estimation, and selective adsorption by starch[J]. Cereal Chemistry, 1979, 56: 310-314.

[12] Cohen R, Orlova Y, Kovalev M, et al. Structural and functional properties of amylose complexes with genistein[J]. Journal of Agricultural and Food Chemistry, 2008, 56 (11): 4212-4218.

[13] Renard CMGC, Baron A, Guyot S, et al. Interactions between apple cell walls and native apple polyphenols: Quantification and some consequences[J]. International Journal of Biological Macromolecules, 2001, 29 (2): 115-125.

[14] Bourvellec CL, Guyot S, Renard CMGC. Non-covalent interaction between procyanidins and apple cell wall material[J]. BBA - General Subjects, 2004, 1672 (3): 192-202.

[15] Cai Y, Gaffney SH, Lilley TH, et al. Cheminform abstract: Polyphenol interactions. Part 4. Model studies with caffeine and cyclodextrins[J]. Cheminform, 1991, 22 (11): 51.

[16] Fayad N, Marchal L, Billaud C, et al. Comparison of β-cyclodextrin effect on polyphenol oxidation catalyzed by purified polyphenol oxidase from different sources[J]. Journal of Agricultural and Food Chemistry, 1997, 45 (7): 2442-2446.

[17] Ishizu T, Kintsu K, Yamamoto H. NMR study of the solution structures of the inclusion complexes of β-cyclodextrin with (+)-catechin and (-)-epicatechin[J]. The Journal of Physical Chemistry B, 1999, 103 (42): 8992-8997.

[18] Kriz Z, Koca J, Imberty A, et al. Investigation of the complexation of (+)-catechin by beta-cyclodextrin by a combination of NMR, microcalorimetry and molecular modeling techniques[J]. Organic & Biomolecular Chemistry, 2003, 1 (14): 2590-2595.

[19] Kim JS, Kwon CS, Son KH. Inhibition of alpha- glucosidase and amylase by luteolin, a flavonoid[J]. Bioscience, Biotechnology, and Biochemistry, 2000, 64 (11): 2458-2461.

[20] Lee YA, Cho EJ, Tanaka T, et al. Inhibitory activities of proanthocyanidins from persimmon against oxidative stress and digestive enzymes related to diabetes[J]. Journal of Nutritional Science and Vitaminology, 2007, 53 (3): 287-292.

[21] Li Y, Gao F, Gao F, et al. Study on the interaction between 3 flavonoid compounds and alpha-amylase by fluorescence spectroscopy and enzymatic kinetics[J]. Journal of Food Science, 2009, 74 (3): C199-C203.

[22] Kim HM, Kim JK, Kang LW, et al. Docking and scoring of quercetin and quercetin glycosides against α-amylase receptor[J]. Bulletin of the Korean Chemical Society, 2010, 31 (2): 461-463.

[23] Narita Y, Inouye K. Kinetic analysis and mechanism on the inhibition of chlorogenic acid and its components against porcine pancreas alpha-amylase isozymes I and II[J]. Journal of Agricultural and Food Chemistry, 2009, 57 (19): 9218-9225.

[24] He Q, Lv YP, Yao K. Effects of tea polyphenols on the activities of α-amylase, pepsin, trypsin and lipase[J]. Food Chemistry, 2006, 101 (3): 1178-1182.