Hypoglycemic and hepatoprotective effects of Jerusalem artichoke extracts on streptozotocin-induced diabetic rats

Therapeutic Effects of Milk Thistle (Silybum marianum L.) and Artichoke (Cynara scolymus L.) on Nonalcoholic Fatty Liver Disease in Type 2 Diabetic Rats

BACKGROUND

At present, nonalcoholic fatty liver disease (NAFLD) does not have an approved pharmacologic therapy. The present study investigated the protective effects and possible mechanisms of milk thistle (Silybum marianum L.) and artichoke (Cynara scolymus L.) in treating NAFLD in type 2 diabetic rats.

METHODS

The NAFLD was established in rats after four weeks of type 2 diabetes induction. The animals were treated with pharmaceutical preparations of milk thistle (Livergol®) and artichoke (Atheromod-B®) extracts for eight weeks. After the end of the intervention, oral glucose tolerance, the serum parameters of oxidative stress, liver functional tests, and lipid profiles were evaluated. Histopathological changes were assessed by hematoxylin and eosin staining.

RESULTS

Treatment with preparations of milk thistle and artichoke nonsignificantly improved glucose tolerance in diabetic rats. Both preparations significantly improved serum superoxide dismutase activity and the level of malondialdehyde. Although treatment with milk thistle reduced serum activity of aspartate aminotransferase and serum levels of triglyceride (TG), total cholesterol, and low-density lipoprotein-cholesterol, artichoke extracts only attenuated the serum level of TG. Milk thistle also effectively protected the liver from histological changes.

CONCLUSIONS

Milk thistle could be a promising pharmacological option for the treatment of NAFLD. Nonetheless, long-term randomized clinical trials are necessary to confirm the observed results.

Unravelling the Helianthus tuberosus L. (Jerusalem Artichoke, Kiku-Imo) Tuber Proteome by Label-Free Quantitative Proteomics

The present research investigates the tuber proteome of the ‘medicinal’ plant Jerusalem artichoke (abbreviated as JA) (Helianthus tuberosus L.) using a high-throughput proteomics technique. Although JA has been historically known to the Native Americans, it was introduced to Europe in the late 19th century and later spread to Japan (referred to as ‘kiku-imo’) as a folk remedy for diabetes. Genboku Takahashi research group has been working on the cultivation and utilization of kiku-imo tuber as a traditional/alternative medicine in daily life and researched on the lowering of blood sugar level, HbA1c, etc., in human subjects (unpublished data). Understanding the protein components of the tuber may shed light on its healing properties, especially related to diabetes. Using three commercially processed JA tuber products (dried powder and dried chips) we performed total protein extraction on the powdered samples using a label-free quantitate proteomic approach (mass spectrometry) and catalogued for the first time a comprehensive protein list for the JA tuber. A total of 2967 protein groups were identified, statistically analyzed, and further categorized into different protein classes using bioinformatics techniques. We discussed the association of these proteins to health and disease regulatory metabolism. Data are available via ProteomeXchange with identifier PXD030744.

Enhanced antitumor activity of inulin-capped Se nanoparticles synthesized using Jerusalem artichoke tubers

An inulin polysaccharide with a molecular weight of ~ 2600 Da was derived from Jerusalem artichoke tubers and referred to as "JAP". Previous studies have shown that inulin can improve glucose tolerance and the liver lipid profile; however, its antitumor activity remains to be examined in detail. Therefore, to investigate the possible improvement of the antitumor activity of JAP, a novel nanostructured biomaterial was constructed by capping Se nanoparticles with JAP using sodium selenite, via a redox reaction with ascorbic acid, and referred to as "JAP-SeNPs". Transmission electron microscopy revealed that the average diameter of JAP-SeNPs is ~ 50 nm, and the C:Se mass ratio in JAP-SeNPs was found to be 15.4:1 by energy-dispersive X-ray spectroscopy. The well-dispersed JAP-SeNPs exhibited a significant in vitro antiproliferative effect on mouse forestomach carcinoma cells at a concentration of 400 μg/mL when incubated for 48 h, with an inhibition rate of 41.5%. Moreover, 38.9% of later apoptotic cells were observed. These results reveal that a combination of Se and JAP can effectively enhance the antitumor activity of polysaccharides obtained from Jerusalem artichoke tubers.

Fermentation of purple Jerusalem artichoke extract to improve the α-glucosidase inhibitory effect in vitro and ameliorate blood glucose in db/db mice

BACKGROUND/OBJECTIVES

Jerusalem artichoke has inhibitory activity against α-glucosidase and decreases fasting serum glucose levels, which may be related to its fructan content. The biological activity of fructan can be influenced by the degree of polymerization. Thus, in this study, the inhibitory effects of original and fermented purple Jerusalem artichoke (PJA) on α-glucosidase were compared in vitro. Additionally, the anti-diabetes effect of Lactobacillus plantarum-fermented PJA (LJA) was studied in a non-insulin-dependent diabetes mellitus animal model (C57BIKsJ db/db).

MATERIALS/METHODS

The water extract of PJA was fermented by L. plantarum, and two strains of Bacillus subtilis to compare their anti-α-glucosidase activities in vitro by α-glucosidase assays. The anti-diabetes effect of LJA was studied in a non-insulin-dependent diabetes mellitus animal model (C57BIKsJ db/db) for seven weeks. During the experiment, food intake, body weight, and fasting blood glucose were measured every week. At the end of the treatment period, several diabetic parameters and the intestinal α-glucosidase activity were measured.

RESULTS

The LJA showed the highest α-glucosidase inhibitory activity in vitro. In the in vivo study, it resulted in a significantly lower blood glucose concentration than the control. Serum insulin and HDL cholesterol levels were significantly higher and the concentrations of triglycerides, non-esterified fatty acids, and total cholesterol were significant lower in mice treated with LJA after seven weeks. In addition, the intestinal α-glucosidase activity was partially inhibited.

CONCLUSIONS

These results suggested that LJA regulates blood glucose and has potential use as a dietary supplement.

Antioxidant and protective effect of inulin and catechin grafted inulin against CCl4-induced liver injury

In this study, the antioxidant activity and hepatoprotective effect of inulin and catechin grafted inulin (catechin-g-inulin) against carbon tetrachloride (CCl4)-induced acute liver injury were investigated. Results showed that both inulin and catechin-g-inulin had moderate scavenging activity on superoxide radical, hydroxyl radical and H2O2, as well as lipid peroxidation inhibition effect. The antioxidant activity decreased in the order of Vc > catechin >catechin-g-inulin > inulin. Administration of inulin and catechin-g-inulin could significantly reduce the elevated levels of serum aspartate transaminase, alanine transaminase and alkaline phosphatase as compared to CCl4 treatment group. Moreover, inulin and catechin-g-inulin significantly increased the levels of hepatic superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione and total antioxidant capacity, whereas markedly decreased the malondialdehyde level when compared with CCl4 treatment group. Notably, catechin-g-inulin showed higher hepatoprotective effect than inulin. In addition, the hepatoprotective effect of catechin-g-inulin was comparable to positive standard of silymarin. Our results suggested that catechin-g-inulin had potent antioxidant activity and potential protective effect against CCl4-induced acute liver injury.