Silymarin from Milk Thistle Fruits Counteracts Selected Pathological Changes in the Lenses of Type 1 Diabetic Rats

Increased therapeutic effect of nanotized silibinin against glycation and diabetes: An in vitro and in silico-based approach

BACKGROUND

The global prevalence of diabetes has increased sharply, with the number of cases expected to rise from 424.9 million in 2017 to 628.6 million by 2045. Flavonoids are plant derived molecules with well-established antioxidant potential in addition to other therapeutic properties. Silibinin is a naturally occurring flavonoid with antioxidant and antidiabetic properties. However, its rapid metabolism and low bioavailability limit its therapeutic effects.

AIMS & OBJECTIVES

In this study, we have synthesized the nanoformulation of silibinin and compared its antiglycating and antidiabetic potential with the soluble form.

METHODOLOGY

The inhibitory effect was tested on carbohydrate-hydrolyzing enzymes as well as glycation of human serum albumin (HSA). The structural and biochemical changes in HSA were assessed by spectroscopic analyses and different assays.

KEY FINDINGS

The nanoforms were found to be better inhibitors of α-amylase and α-glucosidase compared to the bulk forms. Glycation of HSA in the presence of nano-silibinin resulted in the formation of lower level of early and advanced glycation products. This was also confirmed by spectroscopic studies and by estimating protein oxidation and free lysine residues. Molecular docking studies further supported the experimental outcomes. These results indicate that the nano form has significantly stronger antidiabetic and antiglycating effects than the bulk form. Nano-silibinin could therefore be recommended as a dietary supplement for diabetics to help control glycation and other associated complications.

Silymarin reduces retinal microvascular damage in streptozotocin-induced diabetic rats

Diabetic retinopathy is a severe microvascular problem in diabetes mellitus. Silymarin is a flavonoid compound, and according to previous studies, it is a bioactive compound with potent antioxidant and anti-inflammatory properties. This investigation aims to peruse the impact of silymarin against diabetic retinopathy in streptozotocin (STZ)-provoked rats. Thirty-two adult male Wistar rats were randomly allocated into the control group, STZ group, STZ + silymarin (50 mg/kg), and STZ + silymarin (100 mg/kg). STZ rats received silymarin every day until 2 months after diabetes induction. The serum and retinal tissues were collected 2 months after silymarin treatment to determine biochemical and molecular analyses. Silymarin markedly lowered the serum glucose concentration in diabetic rats. Silymarin reduced the increased levels of advanced glycosylated end products (AGEs), the receptors for AGEs (RAGE), and reactive oxygen species (ROS) in diabetic rats. Silymarin also attenuated the phosphorylation of p38 MAP kinase and nuclear factor (NF)-κB p65 and diminished diabetes-induced overexpression of inflammatory cytokines, vascular endothelial growth factor (VEGF), adhesion molecules, and extracellular matrix proteins in STZ rats. Our data suggested that silymarin has protective effects against diabetic retinopathy, which might be related to the inhibition of the AGEs/RAGE axis and its antioxidant and anti-inflammatory activities.