Antioxidant and α-glucosidase inhibitory ingredients identified from Jerusalem artichoke flowers

Jerusalem artichoke diversity in Türkiye: comparative analysis of clone and organ-based biochemical composition

In this study, biochemical analyses were performed for the first time on 22 different Jerusalem artichokes clones collected from different regions of Türkiye and samples from three different organs of each clone, considering the interaction effects. As a result of the study, the interaction effect of clones and sampled organs was found significant for total flavonoids, ascorbic acid, total chlorophyll, pH, H2O2 removal capacity, total dry matter, water soluble dry matter and antioxidant capacity via FRAP. According to the correlation analysis, the highest coefficient among the parameters in the tuber was between titratable acidity and total phenolic matter (0,576). Principal component analysis was used to assess the degree to which the parameters explained the variation in the gene pool. Factors directly and indirectly affecting the amount of water-soluble dry matter in the tuber were examined by path analysis.

Administration of Jerusalem artichoke reduces the postprandial plasma glucose and glucose-dependent insulinotropic polypeptide (GIP) concentrations in humans

Background

The consumption of Jerusalem artichoke has multiple beneficial effects against diabetes and obesity.

Objective

The aim of this study was to determine the effect of a single administration of Jerusalem artichoke tubers on postprandial glycemia and the concentrations of incretin hormones in humans.

Method

Grated Jerusalem artichoke was administered prior to a meal (Trial 1; white rice for prediabetic participants, n = 10). Dose-dependent effect of Jerusalem artichoke (Trial 2; white rice for prediabetic participants, n = 4) and effect prior to the fat-rich meal were also investigated (Trial 3; healthy participants, n = 5) in this pilot study. Circulating glucose, insulin, triglyceride, glucagon, active glucagon-like peptide-1 (GLP-1), and active glucose-dependent insulinotropic polypeptide (GIP) concentrations were subsequently measured in all the trials.

Results

Jerusalem artichoke significantly reduced the glucose and GIP concentrations after the consumption of either meal in Trial 1 and Trial 3, whereas there were no differences in the insulin, glucagon, and active GLP-1 concentrations. Also, there was no significant difference in the triglyceride concentration after the ingestion of the fat-rich meal in Trial 3. The glucose and GIP-lowering effects were dose-dependent, and the consumption of at least 100 g of Jerusalem artichoke was required to have these effects in Trial 2.

Conclusion

This study demonstrates that a single administration of Jerusalem artichoke tubers reduces postprandial glucose and active GIP concentrations in prediabetic and healthy individuals.

Bioactive isocoumarins isolated from a mangrove-derived fungus Penicillium sp. MGP11

Two new isocoumarins penicimarins L-M (1-2), along with seven known analogues (3-9) were isolated from the mangrove-derived fungus Penicillium sp. MGP11. Compounds 1-2 were established by spectroscopic methods and comparison of their circular dichroism (CD) spectra with the literature. All isolated compounds were evaluated for antioxidant and α-glucosidase inhibitory activities. Compound 8 had better antioxidant activity (IC₅₀ = 4.6 μM) than positive control trolox (IC₅₀ = 12.9 μM). Compounds 5, 8 and 9 exhibited α-glucosidase inhibitory activity with the IC₅₀ values of 776.5, 683.7 and 868.7 μM, respectively.

Nutritional value, bioactivity, and application potential of Jerusalem artichoke (Helianthus tuberosus L.) as a neotype feed resource

The large-scale development of herbivorous animal husbandry in China has increased the demand for forage products. However, due to scarce land resources and poor soil quality, forage is in short supply. In particular, high-quality forage in China heavily relies on imports. The contradiction between supply and demand for forage grass products is increasingly notable. Therefore, the development of indigenous new forage resources with a strong ecological adaptability and a high nutritional value is a key to solving this problem. Jerusalem artichoke (JA, Helianthus tuberosus L.), a perennial herb of the genus Helianthus, has advantageous growth traits such as resistance to salinity, barrenness, drought, cold, and disease. The contents of crude protein, crude fiber, and calcium in the optimal harvest period of forage-type JA straw are comparable to those of alfalfa hay at the full bloom stage and the straw of ryegrass and corn at the mature stage. Inulin in JA tubers is a functional ingredient that has prebiotic effects in the gastrointestinal tract of monogastric animals and young ruminants. In addition, some bioactive substances (e.g. flavonoids, phenolic acids, sesquiterpenes, polysaccharides, and amino acids) in JA leaves and flowers have antibacterial, anti-inflammatory, and antioxidant functions as well as toxicities to cancer cells. These functional ingredients may provide effective alternatives to antibiotics used in livestock production. In this review, we summarized the potentials of JA as a feed ingredient from the aspects of nutritional value and fermenting characteristics of the straw, the functions of physiological regulation and disease prevention of inulin in the tubers, and bioactive substances in the leaves and flowers.

Chemical constituents from Urtica fissa stem and their inhibitory effects on α-glucosidase activity

A new unsaturated fatty acid (E)-7,9-diene-11-carbonyl stearic acid (1) and a new lignan 8'-acetyl olivil (2), together with 14 known compounds (3-16), were isolated from the stem of Urtica fissa E. Pritz. Their structures were elucidated by spectroscopic and mass-spectrometric analyses. 8'-Acetyl olivil (2), (6 R,9R)-roseoside (15) and urticol-7-O-β-d-glucopyrannoside (16) exhibited significant inhibition on α-glucosidase activities, with IC₅₀ values less than 9 μM.

Inhibitory Effects of Helianthus tuberosus Ethanol Extract on Dermatophagoides farina body-induced Atopic Dermatitis Mouse Model and Human Keratinocytes

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by complex symptoms. To treat AD without adverse effects, alternative therapeutic agents are required. The tubers of Helianthus tuberosus L. (Jerusalem artichoke) have been used in folk remedies for diabetes and rheumatism. However, its effect on AD development remains unknown. Therefore, this study examined the inhibitory effect of H. tuberosus (HT) on AD skin symptoms using an NC/Nga mouse model and HaCaT keratinocytes. The effect of HT and associated molecular mechanisms were evaluated in Dermatophagoides farina body (Dfb)-induced AD mice and tumor necrosis factor (TNF)-α/interferon (IFN)-γ-stimulated HaCaT keratinocytes by ELISA, western blot, and histological analysis. Topical HT administration attenuated AD skin symptoms in Dfb-induced AD mice, with a significant reduction in the dermatitis score and production of inflammatory mediators. HT also decreased epidermal thickness and mast cell infiltration. Moreover, HT restored filaggrin expression and inhibited adhesion molecules in the mice. These effects were confirmed in vitro. Furthermore, HT suppressed the activation of NF-κB, Akt, and mitogen-activated protein kinase (MAPK) signaling pathways induced by TNF-α/IFN-γ. These results suggest that HT is a potential therapeutic agent or supplement for skin allergic inflammatory diseases such as AD.