The bioactivity of processed garlic (Allium sativum L.) as shown in vitro and in vivo studies on rats

The deleterious effects of cadmium on oxidative stress markers, drug-metabolizing, and antioxidant enzyme activities: Role of Silymarin and Garlic as Antioxidants

Exposure to cadmium has been related to liver and kidney diseases such as polycystic and nephrotic syndrome. It is still unclear how cadmium contributes to these diseases. It is believed that the induction of oxidative stress resulting from the inhibition of antioxidant enzyme activities and changes in drug-metabolizing enzymes in the liver could explain the role of cadmium in the development of different diseases in the kidney and probably other organs. Changes in oxidative stress markers, antioxidant enzymes, and drug-metabolizing enzyme activities were assessed in the liver of male rats exposed to cadmium chloride. Additionally, the protective effects of silymarin and garlic extract against cadmium toxicosis were evaluated. Rats were randomly divided into eight groups as follows, groups 1, 2, 3, 4, and 5, received orally saline, CdCl2 (1 mg/kg), garlic extract [800 mg/kg], silymarin (25 mg/kg) and silymarin plus garlic extract respectively for 28 consecutive days. Rats in groups 6, 7, and 8 were pretreated with the same doses of garlic, silymarin, and garlic plus silymarin, respectively for two hours before cadmium administration. The Western immunoblotting technique was used to investigate the protein expression of cytochrome P450 isozymes. Spectrophotometric methods were used to assess the activity of both antioxidant- and drug-metabolizing enzymes. Free radical levels [measured as thiobarbituric acid reactive substances (TBARS)], catalase, superoxide dismutase, and glutathione peroxidase activities increased whereas the levels of glutathione and the activities of glutathione S-transferase, glutathione reductase, and glutamyl transferase, cytochrome P450, aryl hydrocarbon dehydrogenase (AHH), dimethylnitrosamine-N-demethylase I (DMN-dI), 7-ethoxycoumarine-O-deethylase (ECOD), cytochrome b5 and NADPH-Cytochrome-c-reductase enzyme activities decreased after cadmium treatment. Furthermore, Western immunoblotting data revealed that glutathione peroxidase protein expression increased following cadmium exposure, but cytochrome P450 2E1 and 3A4 expressions were downregulated. However, pretreatment of rats with silymarin or garlic extract or both before cadmium administration was found to restore the protein expression of cytochrome P450 2E1 and 3A4, the level of free radicals, antioxidant enzymes, drug-metabolizing enzyme activities to their normal levels. Similarly, histological studies revealed that silymarin and/or garlic extract reduced the liver damage caused by cadmium. Silymarin and/or garlic extract reduced the adverse effects of cadmium on the activity of both drug-metabolizing and antioxidant enzymes activity. These antioxidants could be provided to those who work in cadmium-based sectors to help them cope with the adverse effects of cadmium on their kidneys. In addition, Inhibiting drug-metabolizing enzyme activity should be considered when administering therapeutic medications to persons exposed to cadmium because most therapeutic drugs and many endogenous substances are largely metabolized by these enzymes.

Does Curing Moisture Content Affect Black Garlic Physiochemical Quality?

This research examined the changes of black garlic (BG) quality attributes when raw materials of different initial moisture contents (iMC) were used. Fresh garlic bulbs (cv. Thai) were shade-dried for eight weeks at a controlled condition at 29 °C and relative humidity (RH) of 55% to the desired iMC (ranging from ca. 50–70%). BG processing was at 75 °C, RH = 80% for ten days. After processing, physiological characteristics and chemical properties of garlic were determined. Results illustrated that fresh garlic with higher moisture content (ca. 70%) resulted in BG of a dark brown colour, sloppy texture, and lesser acidity (pH = 4.44), while samples with lower iMCs (<50%) gave products that were completely black, elastic in texture, and with higher acidity (pH = 3.79). The analysed bioactive compounds, as well as their antioxidative potentials, suggested that the longer the curing time, the higher the functional properties of the finished products, possessing a total phenolic, total flavonoid content, and antioxidant activity of 15.54 mg/kg dry matter sample, 1.53 mg/kg dry matter sample, and 95.39%, respectively. Principle component analysis (PCA) of active metabolites confirmed that sulfur, S-allyl-L-cysteine, and flavonoid were among the main phytochemicals found in the BG. In summary, higher quality BG can be achieved by using raw materials of lower iMC.

The Influence of Plants from the Alliaceae Family on Morphological Parameters of the Intestine in Atherogenic Rats

Bulbs from the Alliaceae family have been well-known and valued spices for thousands of years, not only for their unique flavor and aroma features, but also for their high nutritional and health-promoting values. Long-term or excessive consumption of these vegetables, especially raw garlic, can have side effects in the body (including in the digestive tract), causing a number of pathological changes in the intestinal wall; these changes lead, in turn, to its damage, dysfunction, and disorder development. Therefore, the aim of this study was to investigate the effect of the addition of freeze-dried vegetables from the Alliaceae family, i.e., garlic (Allium sativum L.), white onion, and red onion (Allium cepa L.) on the morphometric parameters (intestinal villi length, crypt depth, thickness of tunica mucosa, and the thickness of tunica muscle) of the jejunum of rats fed a semi-synthetic atherogenic diet (1% dietary cholesterol). In freeze-dried vegetables administered to rats, the contents of selected bioactive ingredients and their antioxidant potentials were determined. The effect of the onion vegetable supplements on growth parameters, serum lipid profile, plasma antioxidant potential, and the intestinal morphological parameters of rats loaded with cholesterol was determined. In an animal experiment, 30 male Wistar rats were divided into 5 diet groups, diet consumption and FER were studied. Supplementation of the atherogenic diet with vegetables improved the blood plasma lipid profiles and atherogenic indices, in a manner that was dependent on the type of supplementation used, with the best hypolipidemic and anti-atherosclerotic effects found in garlic use. The atherogenic diet, as well as the supplementation of this diet with the tested vegetables from the Alliaceae family, influenced the histological changes in the epithelium of the jejunum of rats. The damage to the intestinal mucosa was the greatest in animals fed an atherogenic diet supplemented with garlic. Bearing in mind that the desired beneficial therapeutic or prophylactic effects of onion vegetables (in particular garlic) in the course of various metabolic ailments (including atherosclerosis) are achieved during long-term supplementation, it is important to remember their possible cytotoxic effects (e.g., on the digestive tract) in order to achieve real benefits related to the supplementation with vegetables from the Alliaceae family.

Investigating the Antioxidant Potential of Garlic (Allium sativum) Extracts Through Different Extraction Modes

Background:

Garlic (Allium sativum) possesses health enhancing abilities due to the presence various phytoceutics moities. The current research was deigned to explore the phytochemicals and antioxidant capacity of Pakistani garlic.

Methods:

Garlic extracts were obtained using methanol, hexane and ethyl acetate at different time intervals (35, 50 and 65 min) followed by their polyphenols and flavonoid content determination. Afterwards, the antioxidant potential was also determined.

Results:

The outcomes revealed that the methanolic extracts obtained at 50 min extraction time showed maximum total phenolics as 60.38±0.23 mg GAE/100g and flavonoids as 58.45&amp;#177;1.24 mg/100g. Similarly, the highest DPPH activity (61.59±1.58%) and &amp;#946;-carotene and linoleic acid potential (64.96&amp;#177;1.72%) were also observed for methanolic extract.

Conclusion:

Inferences were made that Pakistani garlic contains myriad of phenolics and flavonoids but the extraction of these components depends upon the solvent/time combination. In this study, methanol proved to be the ideal solvent for the maximum extraction of phytochemicals from garlic.

Evaluation and comparison of the content of total polyphenols and antioxidant activity in garlic (Allium sativum L.)

Garlic (Allium sativum L.) is one of the oldest cultivated plants in the world and highly valued throughout the ages as a culinary spice. It is a hardy perennial belonging to the Alliaceae family. The garlic bulb is the most commonly used portion of the plant, composed of 5 - 20 individual. It is a very good source of manganese, selenium, vitamin C and vitamin B6 (pyridoxine). In addition, garlic is a good source of other minerals, including phosphorous, calcium, potassium, iron and copper. Many of the perceived therapeutic effects of garlic are thought to be due to its active ingredient allicin. This sulphur-containing compound gives garlic its distinctive pungent smell and taste. Garlic possesses antiviral, antibacterial, anti-fungal properties allowing it to stand against all infections. This work has focused on the evaluation and comparison of total content of polyphenols and antioxidant activity in five varieties of garlic - Mojmír, Záhorský, Lukan, Havran and Makoi. Samples of plant material were collected at the stage of full maturity in the area of Nitra. The total content of polyphenols was determined using the spectrophotometric method of Folin-Ciocalteu agents. Determined the content of total polyphenols in garlic were in the range 621.13 mg.kg-1 (Záhorský) to 763.28 mg.kg-1 (Havran). Total polyphenols content in garlic declined in the following order: Havran >Mojmír >Makoi >Lukan >Záhorský. Antioxidant activity was measured by the spectrophotometric method using a compound DPPH (2.2-diphenyl-1-picryhydrazyl). Statistically significant highest value of antioxidant was recorded in 20.22% (Mojmír) and the lowest value was in 13.61% (Záhorský). The values of antioxidant activity observed in the varieties of garlic may be arranged as follows: Mojmír >Havran >Lukan >Makoi >Záhorský. In all the analysed varieties of garlic was confirmed by the strong dependence of the antioxidant activity and the total content of polyphenols.

Garlic-Induced Surgical Bleeding: How Much Is Too Much?

A patient underwent C2-T2 decompression and fusion with excessive intraoperative bleeding and no clear source. The patient denied the use of blood-thinning medications, but had consumed the equivalent of 12 g garlic daily in the days leading up to the surgery. He was treated with desmopressin acetate (DDAVP) and cryoprecipitate with adequate control of bleeding. Garlic is known to have an antiplatelet effect, although the dose range necessary to create a bleeding abnormality has not yet been well described nor has the effect of taking garlic with sertraline or other agents with an established or potential effect on coagulation.

Aged garlic has more potent antiglycation and antioxidant properties compared to fresh garlic extract in vitro

Protein glycation involves formation of early (Amadori) and late advanced glycation endproducts (AGEs) together with free radicals via autoxidation of glucose and Amadori products. Glycation and increased free radical activity underlie the pathogenesis of diabetic complications. This study investigated whether aged garlic has more potent antiglycation and antioxidant properties compared to fresh garlic extract in vitro in a cell-free system. Proteins were glycated by incubation with sugars (glucose, methylglyoxal or ribose) ±5–15 mg/mL of aged and fresh garlic extracts. Advanced glycation endproducts were measured using SDS-PAGE gels and by ELISA whereas Amadori products were assessed by the fructosamine method. Colorimetric methods were used to assess antioxidant activity, free radical scavenging capacity, protein-bound carbonyl groups, thiol groups and metal chelation activities in addition to phenolic, total flavonoid and flavonol content of aged and fresh garlic extracts. Aged garlic inhibited AGEs by 56.4% compared to 33.5% for an equivalent concentration of fresh garlic extract. Similarly, aged garlic had a higher total phenolic content (129 ± 1.8 mg/g) compared to fresh garlic extract (56 ± 1.2 mg/g). Aged garlic has more potent antiglycation and antioxidant properties compared to fresh garlic extract and is more suitable for use in future in vivo studies.

Evaluation of fibrinolytic and antioxidant effects of Allium affine hydroalcoholic extract

Allium affine is a member of Amaryllidaceae family, which grows wildly in some western regions of Iran. Limited information is available about the pharmacological activities of this plant. The present study aimed to evaluate the fibrinolytic and antioxidant effects of hydroalcoholic extract of A. affine aerial parts. The in vitro antioxidant properties of the extract were evaluated by total phenolic content assay, 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity and ferric reducing antioxidant power (FRAP) assay. The in vivo studies included the determination of hydroperoxides level and FRAP value in serum samples of rats receiving i.p. injections of the plant extract for 21 days. The fibrinolytic activity of the extract was quantitatively evaluated by measuring the clot weight. In vitro antioxidant analysis exhibited the promising potential of DPPH scavenging and total antioxidant capacity of A. affine extract. In the in vivo analysis, A. affine extract reduced the serum hydroperoxides level and increased the serum total antioxidant capacity in rats. In vitro fibrinolytic assay also elucidated notable thrombolytic activity of the plant extract. The results of this study revealed the valuable antioxidant and in vitro fibrinolytic activities of A. affine extract. Further studies are needed for better evaluation of anticoagulant and thrombolytic activities of this plant and understanding its detailed mechanisms.

Relation of allium vegetables intake with head and neck cancers: evidence from the INHANCE consortium

SCOPE

Only a few studies analyzed the role of allium vegetables with reference to head and neck cancers (HNC), with mixed results. We investigated the potential favorable role of garlic and onion within the International Head and Neck Cancer Epidemiology (INHANCE) Consortium.

METHODS AND RESULTS

We analyzed pooled individual-level data from eight case-control studies, including 4590 cases and 7082 controls. We estimated odds ratios (ORs) and 95% confidence intervals (CIs) for associations between garlic and onion intakes and HNC risk. Compared with no or low garlic use, the ORs of HNC were 0.95 (95% CI 0.71-1.27) for intermediate and 0.74 (95% CI 0.55-0.99) for high garlic use (p for trend = 0.02). The ORs of HNC for increasing categories of onion intake were 0.91 (95% CI 0.68-1.21) for >1 to ≤3 portions per week, and 0.83 (95% CI 0.60-1.13) for >3 portions per week (p for trend = 0.02), as compared to <1 portion per week. We found an inverse association between high onion intake and laryngeal cancer risk (OR = 0.69; 95% CI 0.54-0.88), but no significant association for other subsites.

CONCLUSION

The results of this pooled-analysis support a possible moderate inverse association between garlic and onion intake and HNC risk.

Effect of garlic powder tablet on carotid intima-media thickness in patients with coronary artery disease: a preliminary randomized controlled trial

BACKGROUND/OBJECTIVES

This study was designed to investigate whether garlic powder tablets in adjunct to conventional medical treatment could have an effect on carotid intima-media thickness (CIMT) and plasma lipoproteins and lipids in patients with coronary artery disease (CAD).

SUBJECTS/METHODS

A randomized, placebo-controlled, clinical trial was conducted on 56 patients with CAD between the ages of 25 and 75 years. The patients were randomly divided into two groups: garlic group (n = 27), receiving garlic powder tablet (1200 µg allicin/tab) twice daily and the placebo group (n = 29), receiving placebo for 3 months. The rate of atherosclerosis progression was measured by B-mode ultrasonography as the increase in CIMT.

RESULTS

After 3 months of taking garlic tablets, CIMT values had minor variations (0.009 ± 0.007 mm reduction from baseline), while in the placebo group, an increase in CIMT values was observed (0.04 ± 0.01 mm increase from baseline). After 3 months of treatment, mean CIMT difference from baseline was significantly differ between the two groups (p < 0.001). Plasma lipids and lipoproteins (total cholesterol, triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, Apolipoprotein A1 and Apolipoprotein B) did not differ between the two groups.

CONCLUSIONS

The results suggest that dry garlic powder tablet is superior to placebo in prevention of CIMT progression in patients with CAD and may be considered as an adjunct treatment for atherosclerosis.

The favorable effects of garlic intake on metabolic profiles, hs-CRP, biomarkers of oxidative stress and pregnancy outcomes in pregnant women at risk for pre-eclampsia: randomized, double-blind, placebo-controlled trial

OBJECTIVE

This study was performed to determine the favorable effects of garlic on metabolic status and pregnancy outcomes among pregnant women at risk for pre-eclampsia.

METHODS

This randomized, double-blind, placebo-controlled trial was conducted among 44 pregnant women, primigravida, aged 18-40 years old at 27 weeks' gestation with positive roll-over test. Participants were randomly assigned to receive either one garlic tablet (equal to 400 mg garlic and 1 mg allicin) (n = 22) or placebo (n = 22) once daily for 9 weeks. Fasting blood samples were taken at baseline and after 9 weeks' intervention to measure metabolic profiles and biomarkers of oxidative stress.

RESULTS

Administration of garlic compared with the placebo resulted in decreased levels of serum high sensitivity C-reactive protein (hs-CRP) (-1425.90 versus 1360.50 ng/mL, p = 0.01) and increased plasma glutathione (GSH) (+98.10 versus. -49.87 µmol/l, p = 0.03). A trend toward a significant effect of garlic intake on reducing fasting plasma glucose (FPG) (p = 0.07), insulin (p = 0.09) and increasing quantitative insulin sensitivity check (QUICKI) (p = 0.05) was also observed.

CONCLUSION

Consumption of garlic for 9 weeks among pregnant women at risk for pre-eclampsia led to decreased hs-CRP and increased GSH, but did not affect lipid profiles, total antioxidant capacity (TAC) and pregnancy outcomes.

Selection of functional lactic acid bacteria as starter cultures for the fermentation of Korean leek (Allium tuberosum Rottler ex Sprengel.)

The purpose of this research was to find safe and suitable starter cultures for the fermentation of Korean leek (Allium tuberosum Rottler), also known as garlic chives or Oriental garlic. This traditional herb has several functional properties and a strong flavour; its leaves are used as food material. Eighteen strains of lactic acid bacteria (LAB) were isolated from well-fermented leek kimchi. Controlled fermentation of the leek leaves was conducted with 2 strains (Weissella confusa LK4 and Lactobacillus plantarum LK8), selected as potential starter cultures on the basis of their safety properties, and on the pH, total titratable acidity (TTA), and viable cell numbers [colony forming units (CFUml(-1))] achieved during the fermentation. Microbial dynamics was also followed during fermentation by using PCR-DGGE (Denaturing Gradient Gel Electrophoresis) on DNA level. To analyse bioactive compounds such as thiols and allicin (diallyl thiosulfinates), the total flavonoid and polyphenolic contents were determined by colorimetric methods. Functional properties were assessed on the basis of anti-oxidative capacities by determining the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging effect, and ferric reducing antioxidant power (FRAP). W. confusa LK4 rapidly increased during the first stage of leek fermentation, and was mainly responsible for accelerated fermentation during the early period in contrast to L. plantarum LK8, a stronger acid producer during the later stages of fermentation. After 48 h fermentation, leeks fermented with W. confusa LK4 showed the highest radical scavenging effects and reducing ability. The detectable amount of allicin of fermented leeks decreased relative to the change in pH, whereas the concentration of thiols significantly increased. Total flavonoid and poly-phenolic contents changed during fermentation and showed correlation with anti-oxidant effects. We therefore suggest the suitability of W. confusa LK4 as a potential starter culture for fermentation of leeks.

Antioxidant changes during domestic food processing of the white shaft and green leaves of leek (Allium ampeloprasum var. porrum)

BACKGROUND

Evaluating the effect of domestic cooking on the health benefits of vegetables has great practical importance. However, only a limited number of reports provide information on the effect of these treatments on the antioxidant capacity, polyphenol and S-alk(en)yl-L-cysteine sulfoxide (ACSO, e.g. isoalliin and methiin) content of the white shaft and green leaves of leek (Allium ampeloprasum var. porrum).

RESULTS

In the present study, the antioxidant capacity of leek was highly influenced by cooking (blanching, boiling and steaming). Boiling had a negative effect on total phenolic content in the white shaft and green leaves. An obvious increase could be observed in the antioxidant capacity of the steamed green leaves, while steaming did not influence the polyphenolic content. Remarkably, blanching resulted in a slight increase in the ACSO content. Subjecting leek samples to a longer thermal treatment appeared to have a negative influence on the ACSO content in leek. Steaming was also responsible for a decrease in ACSOs. Methiin was less susceptible to heat treatment than isoalliin.

CONCLUSION

In general, steaming appeared to be responsible for better retention of the bioactive compounds present in leek compared with boiling.

Evaluation of garlic cultivars for polyphenolic content and antioxidant properties

Two phenolic compound parameters (total phenolic and flavonoid contents) and 5 antioxidant parameters (DPPH [2, 2-diphenyl-1-picrylhydrazyl] radical scavenging activity, HRSC (hydroxyl radical scavenging capacity), FRAP (ferric ion reducing antioxidant power), CUPRAC (cupric ion reducing antioxidant capacity), and MCA (metal chelating activity) were measured in bulbs and bolts of 43 garlic cultivars. The bulbs of cultivar ‘74-x’ had the highest phenolic content (total phenolic, flavonoids) and the strongest antioxidant capacity (DPPH, FRAP, and CUPRAC), followed by bulbs of cultivar ‘Hanzhong purple’; the bulbs of cultivar ‘Gailiang’ had the lowest phenolic content and antioxidant capacity (FRAP, CUPRAC, MCA). The bolts of ‘Hanzhong purple’ also had higher phenolic content. Principal components analysis (PCA) separated the cultivars into 3 groups according to phenolic and flavonoid contents and strength of antioxidant activity. The first group had higher HRSC, FRAP, and flavonoid content; the second group had higher total phenolic content and MCA; some cultivars in the third group had higher HRSC and FRAP. All 8 test garlic bulb extracts successfully prevented Human Vascular Endothelial Cell death and significantly prevented reactive-oxygen species (ROS) formation in oxidative stress model, in which cultivar ‘74-x’ had highest protection capability, following by cultivar ‘Hanzhong purple’, and the bulbs of cultivar ‘No. 105 from Korea’ had the lower protection capability against cell death and ROS formation. The protection capability in vivo of these garlic cultivars was consistent with their phenolic content and antioxidant capacity.

Methods of measurement and evaluation of natural antioxidant capacity/activity (IUPAC Technical Report)

The chemical diversity of natural antioxidants (AOXs) makes it difficult to separate, detect, and quantify individual antioxidants from a complex food/biological matrix. Moreover, the total antioxidant power is often more meaningful to evaluate health beneficial effects because of the cooperative action of individual antioxidant species. Currently, there is no single antioxidant assay for food labeling because of the lack of standard quantification methods. Antioxidant assays may be broadly classified as the electron transfer (ET)- and hydrogen atom transfer (HAT)-based assays. The results obtained are hardly comparable because of the different mechanisms, redox potentials, pH and solvent dependencies, etc. of various assays. This project will aid the identification and quantification of properties and mutual effects of antioxidants, bring a more rational basis to the classification of antioxidant assays with their constraints and challenges, and make the results more comparable and understandable. In this regard, the task group members convey their own experiences in various methods of antioxidants measurement.

Impact of JNK1, JNK2, and ligase Itch on reactive oxygen species formation and survival of prostate cancer cells treated with diallyl trisulfide

PURPOSE

In our previous study, we demonstrated that diallyl trisulfide (DATS) induced iron-dependent G2-M arrest of prostate cancer cell cycle. Moreover, ferritin degradation and an increase of labile iron pool has been linked to the activation of the JNK signaling axis. In the present work, we extended this study to determine which of the c-jun kinases is responsible for ferritin degradation and the role of iron in DATS-induced cell death. We hypothesized that JNK1 activates Itch ligase which will lead to ferritin ubiquitination, an increase in iron-dependent ROS formation and cell death.

METHODS

PC-3 prostate cancer cells were used in this study. Cell viability, concentration of ROS, labile iron pool, and changes in ferritin and P-Itch and DNA damage were determined.

RESULTS

We observed that DATS induced ferritin degradation through JNK, Itch signaling axis. DATS did not induce neither ROS formation nor increase the LIP in JNK1-DN transfected cells. We also observed that DATS increased JNK-dependent activating phosphorylation of E3ligase Itch. The cells transfected with inactive form of Itch were more resistant against cytotoxicity of DATS and showed lower DATS-induced ferritin degradation. Desferrioxamine a specific iron chelator had no effect neither on cell viability nor DNA damage evaluated by comet assay.

CONCLUSIONS

These results suggest that JNK1-dependent increase in LIP is mediated by Itch ubiquitin ligase.