Inhibitory effect of plant essential oils on α-glucosidase.

Diabetes mellitus, associated with α-glucosidase, has been considered as a chronic metabolic disorder, seriously affecting human health. Thus, searching natural α-glucosidase inhibitors and investigating their inhibition mechanism are urgently important. In this study, sixty-two essential oils (EOs), derived from aromatic plants, were found to exert different inhibition on α-glucosidase. The further study revealed that the most potent EOs against α-glucosidase were chuan-xiong, fructus cnidii, sacha inchi, aloe, ganoderma lucidum spore and ginger with IC50 values of 3.02, 2.88, 7.37, 5.06, 5.32 and 7.40 µg/mL. Moreover, the inhibitory mechanism and kinetics studies found that chuan-xiong and sacha inchi were reversible and mixed-type inhibitors. Fructus cnidii, aloe, ganoderma lucidum spore and ginger were reversible and uncompetitive-type inhibitors. It is suggested that EOs, being of natural origin, would be promising anti-α-glucosidase agents.

Safety Assessment of Canola Oil Extracted by Aid of Pulsed Electric Field: Genetic, Acute and Subacute Toxicity.

Pulsed electric field (PEF) is a nonthermal technology resulting in the rupture of cell membranes and increasing the electrical conductivity and the permeability of intracellular material. There was little work about the safety of food treated by PEF. The acute, subacute oral, and genetic toxicities were investigated to explore the safety of canola oil extracted by aid of PEF treatment (PTCO). The results showed that no negative consequences were caused by PEF. PTCO was regarded as practically non-toxic with a LD50 higher than 40 g/kg bw. No oil intake-related mortality, clinical, weight gain and organ coefficient abnormalities were observed. The histopathological symptoms indicated a mild load but not obvious toxicities on liver and kidney. The 28-day subacute toxicity test confirmed that less than 10 g/kg·d bw of oil intake did not exhibit any intake-related changes in physical, physiological, biochemical, hematological, and histopathological signs. The less than 4 of atherosclerosis index suggested that no risk of cardiovascular disease caused by PTCO intake. It was speculated that the PEF treatment would not cause any safety issues to food products.

Immunostimulatory and antioxidant activities of the selenized polysaccharide from edible Grifola frondosa.

Grifola frondosa polysaccharide (GFP2) was extracted and purified by anion-exchange chromatography. A selenized G. frondosa polysaccharide, SeGFP2, was modified in selenylation by nitric acid-sodium selenite (HNO3-Na2SeO3) method. Structural features were investigated, and the lymphocyte proliferation and antioxidant activities were compared taking GFP2 as control. SeGFP2 with a molecular weight of 2.12 × 104 Da was composed of mannose, glucose, and galactose with a ratio of 3.5:11.8:1.0. A typical absorption of selenium ester was observed in SeGFP2 molecule. SeGFP2 was proposed as a branched polysaccharide, which consisted of 1,3-D-Glcp, 1,6-D-Glcp, 1,4,6-D-Galp, and 1,3,6-D-Manp. SeGFP2 showed a linear filamentous structure with some branches. SeGFP2 could significantly promote T- or B-lymphocyte proliferation and the enhancement was higher than GFP2. The in vitro antioxidant activities of SeGFP2 were more potent than GFP2. These present data suggested that selenylation could significantly improve the lymphocyte proliferation and in vitro antioxidant activities of GFP2.

Inhibition of plant essential oils and their interaction in binary combinations against tyrosinase.

Background: Essential oils (EOs), derived from aromatic plants, exhibit properties beneficial to health, such as anti-inflammatory, anti-oxidative, antidiabetic, and antiaging effects. However, the effect of EOs and their interaction in binary combinations against tyrosinase is not yet known. Objective: To evaluate the underlying mechanisms of EOs and their interaction in binary combinations against tyrosinas. Design: We explored to investigate the inhibitory effect of 65 EOs and the interaction among cinnamon, bay, and magnolia officinalis in their binary combinations against tyrosinase. In addition, the main constituents of cinnamon, bay, and magnolia officinalis were analyzed by gas chromatography-mass spectrometry (GC-MS). Results: The results showed that the most potent EOs against tyrosinase were cinnamon, bay, and magnolia officinalis with IC50 values of 25.7, 30.8, and 61.9 µg/mL, respectively. Moreover, the inhibitory mechanism and kinetics studies revealed that cinnamon and bay were reversible and competitive-type inhibitors, and magnolia officinalis was a reversible and mixed-type inhibitor. In addition, these results, assessed in mixtures of three binary combinations, indicated that the combination of cinnamon with bay at different dose and at dose ratio had a strong antagonistic effect against tyrosinase. Magnolia officinalis combined with cinnamon or bay experienced both antagonistic and synergistic effect in anti-tyrosinase activity. Conclusion: It is revealed that natural EOs would be promising to be effective anti-tyrosinase agents, and binary combinations of cinnamon, bay, and magnolia officinalis might not have synergistic effects on tyrosinase under certain condition.

Construction of Loose Positively Charged NF Membrane by Layer-by-Layer Grafting of Polyphenol and Polyethyleneimine on the PES/Fe Substrate for Dye/Salt Separation.

The effective separation of dyes and inorganic salts is highly desirable for recycling inorganic salts and water resource in printing and dyeing wastewater treatment. In this work, tannic acid (TA) and polyethyleneimine (PEI) were grafted on the PES/Fe ultrafiltration membrane via the coordination assembly and Michael addition strategy to fabricated a loose nanofiltration membrane (LNM). The effect of PEI concentration on membrane morphologies and properties was systematically investigated. The membrane surface becomes more hydrophilic and transforms into positive charge after the PEI grafting. The optimized PES/Fe-TA-PEI membrane possesses high pure water flux (124.6 L·m-2·h-1) and excellent dye rejections (98.5%, 99.8%, 98.4%, and 86.4% for Congo red, Eriochrome black T, Alcian blue 8GX, and Bromophenol blue, respectively) under 2 bar operation pressure. Meanwhile, the LNM showed a high Alcian blue 8GX rejection (>98.4%) and low NaCl rejection (<5.3%) for the dye/salt mixed solutions separation. Moreover, the PES/Fe-TA-PEI LNM exhibited good antifouling performance and long-term performance stability. These results reveal that such LNM shows great potential for effective fractionation of dyes and salts and recycling of textile wastewater.

Design, Synthesis, and Activity Study of Cinnamic Acid Derivatives as Potent Antineuroinflammatory Agents.

Neuroinflammatory cytokines are promising therapeutic targets for the treatment of Alzheimer's disease. Herein, we described our efforts toward the investigation of cinnamic acid derivatives as antineuroinflammatory agents. Intensive structural modifications led to the identification of compound 4f as the most effective antineuroinflammatory agent in vitro. The oral administration of compound 4f could reverse lipopolysaccharide (LPS)-induced memory disturbance and normalize glucose uptake and metabolism in the brains of mice. Further biological studies in vivo revealed that compound 4f was directly bound to the mitogen-activated protein kinase (MAPK) signaling pathway, resulting in suppression of its downstream signaling pathway by blocking neuroinflammatory progression. Docking studies showed that compound 4f could be inserted into the active pocket of interleukin-1ß (IL-1ß). Furthermore, it was confirmed that compound 4f formed hydrogen bonds with SER84 to enhance the binding affinity. Taken together, these results are of great importance in the development of cinnamic acid derivatives for the treatment of Alzheimer's disease.

Synergistic effect of tolfenamic acid and glycyrrhizic acid on TPA-induced skin inflammation in mice.

Tolfenamic acid (TA) and glycyrrhizic acid (GA) are well-known components with anti-inflammatory properties. However, their combined effects on inflammation have not been well studied. The present study aimed to investigate the in vivo anti-inflammatory effects of TA combined with GA using a 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced mouse ear edema model, as well as the underlying mechanisms thereof. The results indicated that TA combined with GA led to a stronger inhibition on TPA-induced mouse ear edema compared to the singular treatments. In addition, the combined treatment significantly alleviated subcutaneous tissue inflammation caused by TPA. Further mechanistic investigations demonstrated that TA combined with GA decreased the levels of TPA-induced interleukin-1ß (IL-1ß), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). Furthermore, the combined treatment effectively inhibited nuclear factor-κB (NF-κB), extracellular signal-regulated kinase (ERK1/2), c-Jun N-terminal kinase (JNK), phosphor-ERK1/2 and phosphor-JNK, which was accompanied by blocking of the activation and the phosphorylation in mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K)/Akt signaling pathways. Collectively, our findings revealed that different anti-inflammatory components used in combination lead to enhanced inhibitory effects against inflammation.

Suppressive effect of glycyrrhizic acid against lipopolysaccharide-induced neuroinflammation and cognitive impairment in C57 mice via toll-like receptor 4 signaling pathway.

BACKGROUND: Glycyrrhizinic acid (GA), a major active ingredient enriched in the roots of licorice, possesses well-confirmed anti-inflammatory effects. OBJECTIVE: To evaluate the underlying mechanisms of GA against lipopolysaccharide (LPS)-induced chronic neuroinflammation and memory impairment. DESIGN: We explored to investigate the effects of GA on neuroinflammation and memory impairment in an LPS-induced Alzheimer's mouse model. RESULTS: Data of micro-PET/CT imaging and morris water maze test suggested that GA, when administrated orally, could reverse LPS-induced abnormalized glucose intake and metabolism in the brain and alleviate LPS-induced memory loss and cognitive defects in mice. Histological and immunohistochemical staining results revealed that GA treatment suppressed overexpressions of pro-inflammatory cytokines of IL-1 ß and TNF-α in the brain of C57 mice by inhibiting toll-like receptor 4 (TLR4) signaling pathway activation. CONCLUSION: Our findings suggest that GA may be a therapeutic agent for the treatment of neuroinflammation and cognitive impairment.

Glycyrrhizic acid from licorice down-regulates inflammatory responses via blocking MAPK and PI3K/Akt-dependent NF-κB signalling pathways in TPA-induced skin inflammation.

Glycyrrhizinic acid (GA), a principal component derived from licorice which is used extensively as a natural sweetener and traditional folk herbal medicine, is attracting considerable attention because of its broad range of bioactivities. However, the anti-inflammatory mechanism of GA on 12-O-tetradecanoylphorbol-13-acetate (TPA)-mediated skin inflammation has not been elucidated. Herein, we investigated the anti-inflammatory activity of GA by using a TPA-induced mouse ear model. It was indicated that GA, applied topically onto mouse ears, effectively inhibited the TPA-mediated expressions of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in a dose-dependent manner, respectively. Mechanistic investigations demonstrated that GA down-regulated the expressions of IκBα and p65 and blocked the phosphorylation of IκBα and p65 in TPA-induced mouse skin. Moreover, GA significantly inhibited the TPA-mediated activation of extracellular signal-regulated kinase (ERK1/2), p38 mitogen-activated protein kinase (MAPK), and phosphatidylinositol 3-kinase (PI3K)/Akt, which are upstream of nuclear factor-kB (NF-κB). Taken together, these results indicated that GA, being of natural origin, may be a potential agent for preventing inflammatory diseases.

Glabridin, an isoflavan from licorice root, ameliorates imiquimod-induced psoriasis-like inflammation of BALB/c mice.

In this paper, we investigate the effect of glabridin (Glab) on psoriasis. We observed that Glab significantly suppressed the levels of nitric oxide (NO), NF-κB subunit p65, interleukin (IL)-6, and IL-1ß in lipopolysaccharide (LPS)-stimulated HaCaT cells. In addition, Glab treatment reduced the expression of IL-17A, IL-22, and IL-23 in TNF-α-stimulated-HaCaT cells. These findings prompted us to test whether Glab could be used to treat psoriasis in vivo. The effects of Glab on PASI scores, histopathological changes, oxidative/anti-oxidative indexes and pro-inflammatory cytokines in IMQ-induced mice were investigated. The results indicated that Glab could reduce the PASI scores and ameliorate the deteriorating histopathology. Interestingly, RT-PCR revealed that Glab significantly decreased the mRNA expression of p65, IL-6, IL-1ß, IL-17A, IL-22, and IL-23. These results were confirmed by Western blot analysis and immunohistochemistry staining. In conclusion, our present study revealed that Glab had beneficial effects on psoriasis, and the underlying mechanism may be associated with the downregulation of pro-inflammatory cytokines and the improvement of antioxidant status. Hence, Glab is a promising candidate molecule for development of effective psoriasis therapies.

Synthesis of carbazole derivatives containing chalcone analogs as non-intercalative topoisomerase II catalytic inhibitors and apoptosis inducers.

Novel topoisomerase II (Topo II) inhibitors have gained considerable interest for the development of anticancer agents. In this study, a series of carbazole derivatives containing chalcone analogs (CDCAs) were synthesized and investigated for their Topo II inhibition and cytotoxic activities. The results from Topo II mediated DNA relaxation assay showed that CDCAs could significantly inhibit the activity of Topo II, and the structure-activity relationship indicated the halogen substituent in phenyl ring play an important role in the activity. Further mechanism studies revealed that CDCAs function as non-intercalative Topo II catalytic inhibitors. Moreover, some CDCAs showed micromolar cytotoxic activities. The most potent compound 3h exhibited notable growth inhibition against four human cancer cell lines. Flow cytometric analysis revealed that compounds 3d and 3h arrested the HL-60 cells in sub G1 phase by induction of apoptosis. It was further confirmed by Annexin-V-FITC binding assay. Western blot analysis revealed that compound 3h induces apoptosis likely through the activation of caspase proteins.

Potent inhibitory effect of silibinin from milk thistle on skin inflammation stimuli by 12-O-tetradecanoylphorbol-13-acetate.

Silibinin, a major polyphenol in milk thistle, has been reported to have multiple pharmacological activities; therefore, there is an urgent need to well understand how silibinin works on inflammation-associated skin diseases. We herein designed silibinin on 12-O-tetradecanoylphorbol-13-acetate (TPA)-stimulated skin inflammation to test its inhibitory effects. It was demonstrated that silibinin, applied topically onto mouse ears following TPA stimulation, effectively down-regulated the expressions of TPA-induced interleukin-1ß (IL-1ß), interleukin-6 (IL-6), necrosis factor-alpha (TNF-α) and cyclooxygenase-2 (COX-2) in a dose-dependent manner. Further mechanistic investigations indicated that silibinin suppressed the expression of IκB kinase (IKK) by inhibiting the phosphoinositide 3-kinase/protein kinase B (PI3K/Akt) signaling pathway, and thereby suppressing TPA-stimulated nuclear factor-κB (NF-κB) activation. Promisingly, silibinin, used for transdermal application, may be a potent naturally occurring anti-inflammatory agent for the prevention of inflammation-associated skin diseases.