In vitro and in vivo antihypertensive and antioxidant activities of fermented roots of Allium hookeri

Objective

To evaluate antihypertensive and antioxidant activities of Allium hookeri root (AHR) fermented with Lactobacillus plantarum, Leuconostoc mesenteroides, and Weissella cibaria.

Methods

The novel fermented AHR products using L. plantarum, L. mesenteroides, and W. cibaria were developed and ACE inhibitory activity, DPPH radical scavenging activity, hydroxyl radical scavenging activity, superoxide anion radical scavenging activity, total phenolic content, and total thiosulfinate content were determined. The antihypertensive and antioxidant effects of fermented AHR were further investigated in spontaneously hypertensive rats (SHRs).

Results

Administration of fermented AHR to SHRs had an attenuating effect on both diastolic and systolic blood pressure. The SHRs treated with fermented AHR showed lower plasma ACE activity and higher plasma NO levels. Furthermore, fermented AHR administration led to parallel improvements in plasma oxidative stress biomarkers in SHRs.

Conclusion

Our results highlight the potential usefulness of fermented AHR for the prevention of hypertension.

Allium hookeri Extracts Improve Scopolamine-Induced Cognitive Impairment via Activation of the Cholinergic System and Anti-Neuroinflammation in Mice

Allium hookeri (AH) is a medicinal food that has been used in Southeast Asia for various physiological activities. The objective of this study was to investigate the activation of the cholinergic system and the anti-neuroinflammation effects of AH on scopolamine-induced memory impairment in mice. Scopolamine (1 mg/kg body weight, i.p.) impaired the performance of the mice on the Y-maze test, passive avoidance test, and water maze test. However, the number of error actions was reduced in the AH groups supplemented with leaf and root extracts from AH. AH treatment improved working memory and avoidance times against electronic shock, increased step-through latency, and reduced the time to reach the escape zone in the water maze test. AH significantly improved the cholinergic system by decreasing acetylcholinesterase activity, and increasing acetylcholine concentration. The serum inflammatory cytokines (IL-1β, IL-6, and IFN-γ) increased by scopolamine treatment were regulated by the administration of AH extracts. Overexpression of NF-κB signaling and cytokines in liver tissue due to scopolamine were controlled by administration of AH extracts. AH also significantly decreased Aβ and caspase-3 expression but increased NeuN and ChAT. The results suggest that AH extracts improve cognitive effects, and the root extracts are more effective in relieving the scopolamine-induced memory impairment. They have neuroprotective effects and reduce the development of neuroinflammation.

Neuroprotective effect of Allium hookeri against H2O2-induced PC12 cell cytotoxicity by reducing oxidative stress

In this study, the anti-oxidative and neuro-protective effects of ethanolic extracts of the dried roots of Allium hookeri were investigated. Total phenolic contents and total flavonoid contents of A. hookeri extract depended on the ethanol concentrations used (50, 70 and 95%). In order to evaluate radical scavenging activity, DPPH and ABTS radical scavenging assays and ferric reducing powers were evaluated. The results showed the 95% ethanol extract of A. hookeri (95AH) had higher phenolic and flavonoid contents, and greater radical scavenging activities than 50 or 70% ethanol extracts of A. hookeri. The neuro-protective effects of 95AH were evaluated using H₂O₂-treated PC12 neuronal cells. Treatment of 95AH increased cell viability and superoxide dismutase and glutathione peroxidase activities, reduced lactate dehydrogenate release, reduced reactive oxygen species production, and increased Bcl-2/Bax ratio. HPLC revealed 95AH was rich in phenolics, especially catechin. These results demonstrate 95AH has substantial anti-oxidative and neuro-protective effects against H₂O₂-induced oxidative stress.

Effect of Allium hookeri Root on Physicochemical, Lipid, and Protein Oxidation of Longissimus Dorsi Muscle Meatball

The antioxidant effects of Allium hookeri root (AHR) were investigated by evaluating lipid and protein oxidation in meatballs during refrigerated storage at 4±1℃. AHR was mixed at concentrations of 0.5% (w/w, T2) and 1% (w/w, T3) with minced longissimus dorsi muscle. Meatballs containing AHR (T2 and T3) were compared to those containing 0.05% (w/w) ascorbic acid (T1) as a reference and without antioxidant as a control. The 2-thiobarbituric acid reactive substances (TBARS) value, disulfide bond formation, carbonyl contents, and volatile basic nitrogen (VBN) value of T2 were lower than those of the control during storage (p<0.05). The pH values of T2 and T3 were higher than that of the control (p<0.05). Texture profile analysis of T2 revealed a lower value compared to the control (p<0.05). Therefore, the VBN value, TBARS value, disulfide bond formation, and carbonyl content in meatball containing AHR were lower than those of the control meatball. These results indicate that AHR improves the quality of meat products and functions as an antioxidant.

An Ethanolic Extract of Allium hookeri Root Alleviates Reflux Esophagitis and Modulates NF-κB Signaling

Reflux esophagitis (RE) is a kind of gastroesophageal reflux disease, of which an esophageal inflammatory lesion is caused by the contents of the stomach and duodenum flowing back into the esophagus. Allium hookeri is a plant possessing both nutritional and medicinal properties. In our study, we investigated the inhibition effect of inflammation of A. hookeri root extract (AHE) on inflammatory RAW264.7 macrophage cells induced by lipopolysaccharide and rat models of RE. The results showed that AHE significantly reduced the production of nitric oxide (NO) and the protein expression levels of various mediators related to inflammation including inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and inflammatory cytokines such as interleukin-1 beta (IL-1β) and tumor necrosis factor-alpha (TNF-α). Furthermore, AHE also inhibited the nuclear translocation of nuclear factor kappa B (NF-κB) by inhibiting the phosphorylation IκBα. In addition, AHE administration significantly ameliorated esophageal mucosal damage upon histological evaluation of RE in rats. AHE was also found to downregulate the expression levels of proteins such as COX-2, TNF-α, and IL-1β in the rat esophagus. AHE markedly attenuated activation of NF-κB and phosphorylation of IκBα at the same time. These results indicated that AHE suppressed LPS-induced inflammatory responses in RAW264.7 cells and may help reduce the development of esophagitis through the modulation of inflammation by regulating NF-κB activation.

Allium hookeri root extract exerts anti-inflammatory effects by nuclear factor-κB down-regulation in lipopolysaccharide-induced RAW264.7 cells

Background

Allium hookeri (AH) is widely consumed as a vegetable and herbal medicine in southeastern Asia. AH has been reported antioxidant, antimicrobial, improvement of bone health and antidiabetic effects. In the present study, we investigated the inhibitory effect of a methanol extract of AH root (AHE) on inflammatory response in lipopolysaccharide (LPS)-induced RAW264.7 cells.

Methods

Initially, characterization of organic sulfur compounds in AHE was determined using high performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS). Cells were incubated with LPS and AHE for 24 h. The productions of nitric oxide (NO), reactive oxygen species (ROS), and inflammation-related cytokines were examined. Gene and protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were assessed by polymerase chain reaction and Western blotting. Key factor, nuclear factor kappa B (NF-κB) was also determined.

Results

AHE contained organosulfur compounds such as alliin and S-allylcysteine by HPLC-ESI-MS. AHE significantly inhibited NO, ROS, and cytokines production in LPS-induced RAW264.7 cells. In addition, AHE treatment inhibited iNOS and COX-2 mRNA and protein levels, leading to a decrease in iNOS-derived NO level. Furthermore, NF-κB activation was, at least in part, suppressed by AHE treatment.

Conclusion

Our data suggest that AHE treatment inhibits the inflammation condition through suppression of iNOS and COX-2 expression via NF-κB down-regulation.

Allium hookeri root protects oxidative stress-induced inflammatory responses and β-cell damage in pancreas of streptozotocin-induced diabetic rats

Background

Water extract from the root of Allium hookeri (AH) shows anti-inflammatory, antioxidant, and free radical scavenging effects. In this study, the ameliorating effects of AH on oxidative stress-induced inflammatory response and β-cell damage in the pancreas of streptozotocin (STZ)-induced type 1 diabetic rats were investigated.

Methods

AH (100 mg/kg body weight/day) was orally administered every day for 2 weeks to STZ-induced diabetic rats. After the final administration of AH, biochemical parameters including glucose, insulin, reactive oxygen species levels, and protein expressions related to antioxidant defense system in the pancreas of STZ-induced diabetic rats.

Results

The diabetic rats showed loss of body weight and increased pancreatic weight, while the oral administration of AH attenuated body and pancreatic weight changes. Moreover, the administration of AH caused a slightly decrease in the serum glucose level and a significant increase in the serum and pancreatic insulin levels in the diabetic rats. AH also significantly reduced the enhanced levels of reactive oxygen species, oxidative stress biomarker, in the serum and pancreas. The diabetic rats exhibited a down-regulation of the protein expression related to antioxidant defense system in the pancreas, but AH administration significantly up-regulated the expression of the heme oxygenase-1 (HO-1). Furthermore, AH treatment was reduced the overexpression of nuclear factor-kappa B (NF-кB)p65 and NF-кBp65-induced inflammatory cytokines such as tumor necrosis factor-α and interleukin-6. In addition, AH treatment was less pancreatic β-cell damaged compared with those of the diabetic rats.

Conclusion

These results provide important evidence that AH has a HO-1 activity on the oxidative stress conditions showing pancreato-protective effects against the development of inflammation in the diabetic rats. This study provides scientific evidence that AH protects the inflammatory responses by modulated NF-кBp65 signaling pathway through activation of HO-1 in the pancreas of STZ-induced diabetic rats.