In our previous study, we reported the renoprotective effect of Hachimi-jio-gan, a Chinese traditional prescription consisting of eight medicinal plants, and also reported the effect of Corni Fructus (Cornus officinalis SIEB. et ZUCC.), a component of Hachimi-jio-gan, on diabetic nephropathy using diabetic rats. In this study, we investigated the effects of morroniside isolated from Corni Fructus on renal damage in streptozotocin-treated diabetic rats. Oral administration of morroniside at a dose of 20 or 100 mg/kg body weight/d for 20 d to diabetic rats resulted in significant decreases in increasing serum glucose and urinary protein levels. Moreover, the decreased levels of serum albumin and total protein in diabetic rats were significantly increased by morroniside administration at a dose of 100 mg/kg body weight/d. In addition, morroniside significantly reduced the elevated serum urea nitrogen level and showed a tendency to reduce creatinine clearance. Morroniside also significantly reduced the enhanced levels of serum glycosylated protein, and serum and renal thiobarbituric acid-reactive substances. Protein expressions related to the advanced glycation endproduct (AGE) level and actions, oxidative stress such as Nε-(carboxyethyl)lysine, as well as receptors for AGE and heme oxygenase-1 were increased in diabetic rats, but the levels were also significantly decreased by the administration of morroniside. This suggests that morroniside exhibits protective effects against diabetic renal damage by inhibiting hyperglycemia and oxidative stress. These results indicate that morroniside is one component partly responsible for the protective effects of Corni Fructus and Hachimi-jio-gan against diabetic renal damage.

Cholinergic dysfunction and oxidative stress are the most common causes of Alzheimer's disease (AD). Safflower seed contains various anti-oxidant and cholinergic improvement compounds, such as serotonin and its derivatives. In the present study, we investigated the protective effects and mechanisms of a safflower seed extract on scopolamine-induced memory impairment in a mouse model. The safflower seed extract was orally administered at a dose of 100 mg kg⁻¹ day⁻¹, and then behavior tests (such as T-maze and novel object recognition tests) were conducted. Acetyl cholinesterase (AChE) activity, reactive oxygen species (ROS) production, and antioxidant enzymes in the brain were measured. In behavior tests, the novel route exploration and object recognition were improved by the administration of the safflower seed extract, which suggests that the safflower seed extract improves memory function in the scopolamine-treated mouse model. In addition, the safflower seed extract-administered group showed inhibition of the AChE activity and improved cholinergic dysfunction. Furthermore, the administration of the safflower seed extract resulted in lower ROS production and higher antioxidant enzyme levels as compared to the scopolamine-treated group, suggesting the protective role of the safflower seed extract against oxidative stress. The results of the present study suggest that the safflower seed extract improves scopolamine-induced memory deficits via the inhibition of cholinergic dysfunction and oxidative stress. Therefore, safflower seeds might become a promising agent for memory improvement in AD patients.

We investigated the antidiabetic potential of proanthocyanidin and its oligomeric form in STZ-induced diabetic model rats anddb/dbtype 2 diabetic mice. Proanthocyanidin ameliorated the diabetic condition by significant decreases of serum glucose, glycosylated protein, and serum urea nitrogen as well as decreases of urinary protein and renal-AGE in STZ-induced diabetic rats and decrease of serum glucose as well as significant decrease of glycosylated protein indb/dbtype 2 diabetic mice. The suppression of ROS generation and elevation of the GSH/GSSG ratio were also observed in the groups administered proanthocyanidin. Moreover, proanthocyanidin, especially its oligomeric form, affected the inflammatory process with the regulation of related protein expression, iNOS, COX-2 and upstream regulators, NF-κB, and the IκB-α. In addition, it had a marked effect on hyperlipidemia through lowering significant levels of triglycerides, total cholesterol, and NEFA. Moreover, expressions in the liver of SREBP-1 and SREBP-2 were downregulated by the administration of proanthocyanidins. The protective effect against hyperglycemia and hyperlipidemia in type 1 and 2 diabetic models was significantly strong in the groups administered the oligomeric rather than polymeric form. This suggests that oligomers act as a regulator in inflammatory reactions caused by oxidative stress in diabetes.

Inhibition of glycogen synthase kinase 3β (GSK-3β) is considered to be the central therapeutic approach against Alzheimer’s disease (AD). In the present study, boiled water extracts of the Kangen-karyu (KK) herbal mixture and its constituents were screened for GSK-3β inhibitory activity. KK is used in traditional Kampo and Chinese medicines for improving cognitive function. The GSK-3β inhibition potential was evaluated by using the Kinase-Glo luminescent kinase assay platform. Furthermore, enzyme kinetics and in silico modeling were performed by using AutoDockTools to demonstrate the mechanism of enzyme inhibition. KK extract significantly inhibited GSK-3β in a concentration-dependent manner (IC₅₀: 17.05 ± 1.14 μg/mL) when compared with the reference drug luteolin (IC₅₀: 2.18 ± 0.13 μM). Among the six components of KK, extracts of Cyperi Rhizoma and Salviae Miltiorrhizae Radix significantly inhibited GSK-3β with IC₅₀ values of 20.68 ± 2.50 and 7.77 ± 1.38 μg/mL, respectively. Among the constituents of the roots of S. miltiorrhiza water extract, rosmarinic acid, magnesium lithospermate B, salvianolic acid A, salvianolic acid B, and salvianolic acid C inhibited GSK-3β with IC₅₀ values ranging from 6.97 to 135.5 μM. Salvianolic acid B was found to be an ATP-competitive inhibitor of GSK-3β and showed the lowest IC₅₀ value (6.97 ± 0.96 µM). In silico modeling suggested a mechanism of action by which the hydrophobic, π–cation, and hydrophilic interactions of salvianolic acid B at ATP and substrate sites are critical for the observed GSK-3β inhibition. Therefore, one of the mechanisms of action of KK against AD may be the inhibition of GSK-3β and one of the active components of KK is the root of S. miltiorrhiza and its constituents: rosmarinic acid, magnesium lithospermate B, and salvianolic acids A, B, and C. Our results demonstrate the pharmacological basis for the use of KK against AD.

The protective effect of 7-O-galloyl-D-sedoheptulose (GS), isolated from Corni Fructus as an active component, against acute renal failure (ARF) induced by glycerol was investigated. The administration of GS led to a decline in the levels of blood urea nitrogen and creatinine; on the other hand, it did not have a significant effect on creatinine clearance. Furthermore, GS also significantly decreased the urine volume and fractional excretion of sodium, but it increased the urine osmolarity, suggesting the protective role of GS against renal dysfunction. Oxidative stress under ARF was attenuated by GS through the inhibition of lipid peroxidation, scavenging of reactive oxygen species (ROS), and elevation of the antioxidative status. Renal oxidative stress is related to the overproduction of ROS by nicotinamide adenine dinucleotide phosphate (NAD(P)H) oxidase; therefore, in the present study, the protein expression of p22phox and NAD(P)H oxidase-4 (Nox-4) was investigated. GS down-regulated the protein expression of p22phox; on the other hand, it did not significantly affect the expression of Nox-4. This indicates that GS inhibits the production of superoxide by regulating a component of NAD(P)H oxidase, p22phox. Furthermore, GS down-regulated the expressions of nuclear factor-κB (NF-κΒ) and inducible nitric oxide (NO) synthase (iNOS), suggesting that GS protects against NO-induced inflammatory pathological conditions under ARF through the regulation of NF-κB and iNOS expressions. The present study indicates that GS exerts a protective effect against ARF through the recovery of renal dysfunction and attenuation of renal oxidative stress by regulating related protein expression.