The effect of dietary garlic on the development of cardiovascular disease

Allicin treats myocardial infarction in I/R through the promotion of the SHP2 axis to inhibit p-PERK-mediated oxidative stress

OBJECTIVE

The study attempted to explore how allicin reduces oxidative stress levels by promoting SHP2 expression to inhibit p-PERK in I/R mice.

METHODS

The GEO database and RNA sequencing were used to predict downstream gene. TTC staining was used to visualize the myocardial infarction area. Masson staining was used to assess the level of fibrosis. IF was used to examine the expression of SHP2, CTGF, ROS. RT-PCR analysis was used to quantify the expression of SHP2 mRNA. Western blot was used to detect the protein expression levels of SHP2, p-PERK, MFN1, NLRP3, NOX2, and NOX3.

RESULTS

GEO and transcriptomic data revealed low expression of SHP2 in the heart tissues I/R mice. In the I/R mouse model, TTC staining result showed that allicin can reduce the area of myocardial infarction; Masson staining results indicated that allicin can reduce fibrosis; Macrophage transcriptome sequencing found SHP2 is a target gene of allicin; Immunofluorescence showed allicin can increase SHP2; qPCR results showed allicin can raise SHP2 mRNA level; Immunofluorescence indicated that allicin can inhibit ROS in myocardial infarction tissue, but the specific SHP2-KD eliminates changes in ROS. Western blot analysis demonstrated allicin can increase SHP2 protein and reduce the expression of p-PERK, MFN1, NLRP3, NOX2, and NOX3; SHP2-KD eliminates the expression differences in p-PERK, MFN1, NLRP3, NOX2, and NOX3.

CONCLUSIONS

Allicin can modulate p-PERK activation by enhancing the expression of SHP2, thereby inhibiting myocardial ischemia-reperfusion-induced oxidative stress in mice.

Characterization of volatile organic compounds with anti-atherosclerosis effects in Allium macrostemon Bge. and Allium chinense G. Don by head space solid phase microextraction coupled with gas chromatography tandem mass spectrometry

Introduction

Allium macrostemon Bge. (AMB) and Allium chinense G. Don (ACGD) are both edible Allium vegetables and named officinal Xiebai (or Allii Macrostemonis Bulbus) in East Asia. Their medicinal qualities involve in lipid lowering and anti-atherosclerosis effects. And steroidal saponins, nitrogenous compounds and sulfur compounds are like the beneficial components responsible for medicinal functions. Sulfur compounds are the recognized main components both in the volatile oils of AMB and ACGD. Besides, few researches were reported about their holistic chemical profiles of volatile organic compounds (VOCs) and pharmacodynamic effects.

Methods

In this study, we first investigated the lipid-lowering and anti-atherosclerotic effects of volatile oils derived from AMB and ACGD in ApoE ^-/- mice with high fat and high cholesterol diets.

Results

The results showed the volatile oils of AMB and ACGD both could markedly reduce serum levels of TG, TC, and LDL-C (p < 0.05), and had no alterations of HDL-C, ALT, and AST levels (p > 0.05). Pathological results displayed they both could obviously improve the morphology of cardiomyocytes and the degree of myocardial fibrosis in model mice. Meanwhile, oil red O staining results also proved they could apparently decrease the lesion areas of plaques in the aortic intima (p < 0.05). Furthermore, head space solid phase microextraction coupled with gas chromatography tandem mass spectrometry combined with metabolomics analysis was performed to characterize the VOCs profiles of AMB and ACGD, and screen their differential VOCs. A total of 121 and 115 VOCs were identified or tentatively characterized in the volatile oils of AMB and ACGD, respectively. Relative-quantification results also confirmed sulfur compounds, aldehydes, and heterocyclic compounds accounted for about 85.6% in AMB bulbs, while approximately 86.6% in ACGD bulbs were attributed to sulfur compounds, ketones, and heterocyclic compounds. Multivariate statistical analysis showed 62 differentially expressed VOCs were observed between AMB and ACGD, of which 17 sulfur compounds were found to be closely associated with the garlic flavor and efficacy.

Discussion

Taken together, this study was the first analysis of holistic chemical profiles and anti-atherosclerosis effects of AMB and ACGD volatile oils, and would benefit the understanding of effective components in AMB and ACGD.

Allium sativum Protease Inhibitor: A Novel Kunitz Trypsin Inhibitor from Garlic Is a New Comrade of the Serpin Family

PURPOSE

This study was aimed to purify and characterize the Protease inhibitor (PI) from a plant Allium sativum (garlic) with strong medicinal properties and to explore its phytodrug potentials.

METHODS

Allium sativum Protease Inhibitor (ASPI) was purified using ammonium sulphate fractionation and Fast Protein Liquid Chromatography on anion exchanger Hi-Trap DEAE column. The purified protein was analyzed for its purity and molecular weight by SDS PAGE. The confirmation of presence of trypsin inhibiting PI was performed by MALDI TOF-TOF and analyzed by MASCOT database. The ASPI was further investigated for its kinetic properties and stability under extreme conditions of pH, temperature and chemical denaturants. Secondary structure was determined by Circular Dichorism (CD) spectroscopy.

RESULTS

ASPI of ~15 kDa inhibited trypsin and matched "truncated kunitz Trypsin Inhibitor (Glycine max)" in MASCOT database. The purified ASPI showed 30376.1371 U/mg specific activity with a fold purity of 159.92 and yield ~93%. ASPI was quite stable in the range of pH 2-12 showing a decline in the activity around pH 4-5 suggesting that the pI value of the protein as ASPI aggregates in this range. ASPI showed stability to a broad range of temperature (10-80°C) but declined beyond 80°C. Further, detergents, oxidizing agents and reducing agents demonstrated change in ASPI activity under varying concentrations. The kinetic analysis revealed sigmoidal relationship of velocity with substrate concentration with Vmax 240.8 (μM/min) and Km value of 0.12 μM. ASPI showed uncompetitive inhibition with a Ki of 0.08±0.01 nM). The Far UV CD depicted 2.0% α -helices and 51% β -sheets at native pH.

CONCLUSIONS

To conclude, purified ~15 kDa ASPI exhibited fair stability in wide range of pH and temperature Overall, there was an increase in purification fold with remarkable yield. Chemical modification studies suggested the presence of lysine and tryptophan residues as lead amino acids present in the reactive sites. Therefore, ASPI with trypsin inhibitory property has the potential to be used as a non-cytotoxic clinical agents.

Garlic extract prevents CCl(4)-induced liver fibrosis in rats: The role of tissue transglutaminase

BACKGROUND AND AIM

Tissue transglutaminase contributes to liver damage in the development of hepatic fibrosis. In a model of neurodegeneration, the therapeutic benefit of cystamine has been partly attributed to its inhibition of transglutaminase activity. Garlic extract contains many compounds structurally related to cystamine. We investigated the anti-fibrotic effect of garlic extract and cystamine as specific tissue transglutaminase inhibitors.

METHODS

Rat liver fibrosis was induced by intraperitoneal injection of carbon tetrachloride (CCl(4)) for 7 weeks. Cystamine or garlic extract was administrated by daily intraperitoneal injection, starting from the day after the first administration of CCl(4). Hepatic function, histology, tissue transglutaminase immunostaining and image analysis to quantify Red Sirius stained collagen deposition were examined. Reverse transcription-polymerase chain reaction to detect alpha-SMA, IL-1beta and tissue transglutaminase expression and Western blot for tissue transglutaminase protein amount were performed. Transglutaminase activity was assayed on liver homogenates by a radio-enzymatic method.

RESULTS

Transglutaminase activity was increased in CCl(4) group and reduced by cystamine and garlic extract (p<0.05). Treatment with cystamine and garlic extract reduced the liver fibrosis and collagen deposition, particularly in the garlic extract group (p<0.01). Moreover, the liver damage improved and serum alanine aminotransferase was decreased (p<0.05). Tissue transglutaminase immunolocalised with collagen fibres and is mainly found in the ECM of damaged liver. Alpha-SMA, IL-1beta, tissue transglutaminase mRNA and tissue transglutaminase protein were down-regulated in the cystamine and garlic extract groups compared to controls.

CONCLUSION

These findings concurrently suggest that transglutaminase may play a pivotal role in the pathogenesis of liver fibrosis and may identify garlic cystamine-like molecules as a potential therapeutic strategy in the treatment of liver injury.

Immunomodulatory activity of a protein isolated from garlic extract on delayed type hypersensitivity

Garlic is known as a potent spice and a medicine with broad therapeutic properties ranging from antibacterial to anticancer, and anticoagulant. One major protein has been isolated and purified; it is the 14-kDa glycoprotein. This protein has shown to have immunomodulatory effects. In this study, two sources of garlic (freshly prepared and commercial tablet) were used. Both sources of garlic were augmented delayed type hypersensitivity (DTH) response, the optimum enhancement were detected at 20 mg/kg. Histological studies indicate that 20 mg/kg caused a hyperplasia and hypertrophy of periarteriolar lymphoid sheath of spleen and paracortical zone of lymph nodes. Partial purified fraction could increase the DTH response comparing to garlic extract, and purified protein could highly increase the DTH response comparing to both garlic extract and partial purified fraction. Garlic at all doses employed did not exhibit any effect on enhancement of antibody titer to SRBC.