Screening and Binding Analysis of Flavonoids with Alpha-Amylase Inhibitory Activity from Lotus Leaf

Abstract

Lotus leaf is gaining growing popularity due to its various benefits and widely usage. In this paper, ten flavonoids in lotus leaf extract were analyzed by high performance liquid chromatography (HPLC). Centrifugal ultrafiltration combined liquid chromatography was used to screen alphaamylase inhibitors from ten flavonoids mixture and the binding degrees ranged from 2.34 to 94.1%. The alpha-amylase inhibition and the 1,1-diphenyl-2-picrylhydrazyl (DPPH) antioxidant activity of ten flavonoids were verified as well. Apigenin, kaempferol and isorhamnetin with relatively higher binding degrees showed higher inhibition on alpha-amylase as well. The interactions between these flavonoids and alpha-amylase were investigated by spectroscopic method. As a result, the fluorescence quenching could be considered as static quenching because the quenching rate constant (K q ) values were higher than 2.0 × 10 10 L mol -1 s -1. The binding constants (log 10 K a ) of ten flavonoids were in the range of 5.971 to 7.417 L mol -1 . The hydrogenation of C 2 =C 3 double bond of apigenin and quercetin decreased the affinity for alpha-amylase (1.92-and 2.82-fold). The hydroxylation on 3 and 3' position decreased the affinity for alpha-amylase. Moreover, the glycosylation with different sugar moiety improved in varying degrees of affinity. The hydrogen bond force might be important in the binding between alpha-amylase and flavonoids.

Polyphenol Profile and Biological Activity Comparisons of Different Parts of Astragalus macrocephalus subsp. finitimus from Turkey

“…In addition, the flowers exhibited the weakest inhibitory activities (IC 50 : 4.94 mg/mL for amylase and 1.41 mg/mL for tyrosinase). The findings could be related with chemical profiles of the tested extracts and some compounds in extracts such as hyperoside [ 70 , 71 ], ferulic acid [ 72 , 73 ], and apigenin [ 74 , 75 ] have been reported as inhibitory agents in earlier studies. A moderate positive correlation was also observed between total phenolic content and the enzyme inhibitory abilities Table 4 .…”

Chemical Composition Analysis Using HPLC-UV/GC-MS and Inhibitory Activity of Different Nigella sativa Fractions on Pancreatic α-Amylase and Intestinal Glucose Absorption

“…Also, it was mentioned that its combination with acarbose showed a great synergic capacity to inhibit α -amylase and glucosidase [ 44 ]. It was recorded that kaempferol, a flavonoid present in the ethanolic fraction by 0.032 mg/100 g of DW, showed a higher inhibition capacity of α -amylase and this could be due to their high binding to the pancreatic enzyme [ 45 ]. Also, catechin, a molecule present with an important quantity in EtOH (89.03) followed by MeOH fraction (19.92), showed its capacity to inhibit the pancreatic α -amylase [ 46 ].…”

Flavonoids from Nelumbo nucifera Gaertn., a Medicinal Plant: Uses in Traditional Medicine, Phytochemistry and Pharmacological Activities

“…Recently, Wang et al demonstrated that N. nucifera leaf flavonoids could prevent diabetes type 2 through the inhibition of α-amylase [51]. In the same way, Liao et al analyzed the binding affinity of ten flavonoids from N. nucifera leaf on α-amylase using spectroscopic methods [52]. They found that, among the tested flavonoids, Kae, Api and Iso displayed the most potent inhibiting potential on α-amylase activity.…”

“…They found that, among the tested flavonoids, Kae, Api and Iso displayed the most potent inhibiting potential on α-amylase activity. Their structure–function experiments also showed that the hydrogenation of the C 2 =C 3 double bond of the flavonoid backbone of Quer and Api as well as the hydroxylation of 3 and 3′ positions decreased the affinity of the flavonoids for this enzyme [52]. Additionally, the methanol extract from seed epicarp of N. nucifera revealed the significant α-amylase inhibiting activity, and was suggested to develop as potential anti-diabetic agents [49].…”