Quercetin and Kaempferol as Multi-Targeting Antidiabetic Agents against Mouse Model of Chemically Induced Type 2 Diabetes

Abstract

Diabetes, a multifactorial metabolic disorder, demands the discovery of multi-targeting drugs with minimal side effects. This study investigated the multi-targeting antidiabetic potential of quercetin and kaempferol. The druggability and binding affinities of both compounds towards multiple antidiabetic targets were explored using pharmacokinetic and docking software (AutoDock Vina 1.1.2). Our findings showed that quercetin and kaempferol obey Lipinski's rule of five and exhibit desirable ADMET (absorption, distribution, metabolism excretion, and toxicity) profiles. Both compounds showed higher binding affinities towards C-reactive protein (CRP), interleukin-1 (IL-1), dipeptidyl peptidase-4 (DPP-IV), peroxisome proliferator-activated receptor gamma (PPARG), protein tyrosine phosphatase (PTP), and sodium-glucose co-transporter-1 (SGLT-1) compared to metformin (the positive control). Both quercetin and kaempferol inhibited α-amylase activity (in vitro) up to 20.30 ± 0.49 and 37.43 ± 0.42%, respectively. Their oral supplementation significantly reduced blood glucose levels (p < 0.001), improved lipid profile (p < 0.001), and enhanced total antioxidant status (p < 0.01) in streptozotocin-nicotinamide (STZ-NA)-induced diabetic mice. Additionally, both compounds significantly inhibited the proliferation of Huh-7 and HepG2 (cancer cells) (p < 0.0001) with no effect on the viability of Vero cell line (non-cancer). In conclusion, quercetin and kaempferol demonstrated higher binding affinities towards multiple targets than metformin. In vitro and in vivo antidiabetic potential along with the anticancer activities of both compounds suggest promise for further development in diabetes management. The combination of both drugs did not show a synergistic effect, possibly due to their same target on the receptors.

Keywords: anticancer activity; kaempferol; molecular docking; multi-target compounds; quercetin; type 2 diabetes.

Figure 1

Chemical structure of quercetin and kaempferol.

Figure 2

Two-dimensional representation of the interaction between quercetin, kaempferol, and metformin within the binding sites of CRP, IL-1, and the active site of DPP-IV. CRP (PDB ID: 1gnh), DPP-IV (PDB ID: 1j2e), and IL1 (PDB ID: 9ilb). Interaction analysis was carried out using BIOVIA Discovery Studio 2021 and the best pose was selected for each ligand.

Figure 3

Two-dimensional representation of quercetin, kaempferol, and metformin interaction within canonical thiazolidinedione (TZD) binding sites of PPARG, active site of PTP, and binding site of SGLT-1. Quercetin (PubChem CID: 5280343), Kaempferol (PubChem CID: 5280863), and Metformin (PubChem CID: 4091). PRARG (PDB ID: 1prg), PTP (PDB ID: 2nt7), and SLGT-1 (PDB ID: 7sla). Interaction analysis was carried out using BIOVIA Discovery Studio 2021 and the best pose was selected for each ligand.

Figure 4

Graph showing the effect of quercetin, kaempferol, their combination, and metformin on blood glucose level. Data are expressed as mean ± SEM, where n = 3 (number of mice in each group). One-way ANOVA (analysis of variance) and Tukey’s multiple comparison test was applied to find the significance level and represented as p-value. ^#### p < 0.0001 shows comparison of diabetic control with normal control, *** p < 0.001 and **** p < 0.0001 show the comparison of other groups with diabetic control. Ctrl received 20% ethanol, representing normal control; Veh (vehicle) received normal saline, served as diabetic control; Quer received quercetin 20 mg/Kg; Kaem received kaempferol 5 mg/Kg; Quer + Kaem group received 10 mg/Kg of quercetin and 2.5 mg/Kg of kaempferol; and Met received metformin 50 mg/Kg served as positive control.

Figure 5

Effect of quercetin, kaempferol, and their combination on lipid profile; (A) serum triglyceride level and (B) cholesterol level of experimental mice. Data are presented as mean ± SEM, where n = 3. One-way ANOVA (analysis of variance) and Tukey’s multiple comparison test were applied to find the significance level and represented as p-value. ^#### p < 0.0001 and ^### p < 0.001 show comparison of diabetic control with normal control, *** p < 0.001 and ** p < 0.01 show the comparison of other groups with diabetic control.

Figure 6

Effect of quercetin, kaempferol, and their combination on TAC status of liver tissue; values are means (n = 3) ± SEM, where n = 3. One-way ANOVA (analysis of variance) and Tukey’s multiple comparison test were applied to find the significance level and represented as p-value. ^### p < 0.001 shows comparison of diabetic control with normal control, *** p < 0.001, ** p < 0.01, and * p < 0.05 show the comparison of other groups with diabetic control. Ctrl, normal control; Veh, vehicle (diabetic control); Quer, quercetin; Kaem, kaempferol; and Met, metformin (positive control).

Figure 7

Effect of quercetin, kaempferol, and their combination on the viability of cancer and non-cancer cell lines. (A–C) Shows the effect of quercetin (36 µg/mL), kaempferol (15 µg/mL), their combination (18 µg/mL quercetin + 7.5 µg/mL kaempferol), and doxorubicin (1.8 µg/mL) on the viability of HepG2, Huh-7 (cancer), and Vero (non-cancer) cell lines, respectively. One-way ANOVA (analysis of variance) and Tukey’s multiple comparison test were applied to find the significance level and represented as p-value. **** p < 0.0001 shows comparison of all treatment groups with both controls. Ctrl1, control with distilled water; Ctrl2, control with 0.1–0.2% dimethyl sulfoxide (DMSO); Quer, quercetin; Kaem, kaempferol; and Doxo, doxorubicin as standard anticancer drug. The absorbance was measured at 570 nm.