Here is an essay on ‘Garlic’ for class 8, 9, 10, 11 and 12. Find paragraphs, long and short essays on ‘Garlic’ especially written for school and college students.
Essay on Garlic
1. Essay on Garlic (As an Anti-Carcinogenic):
Allium vegetables rich in flavonols and organo sulfur compounds have tumor- inhibitory properties. Epidemiologic studies have related consumption of allium vegetables including garlic, onions, leeks, chives, scallions, and shallots to lower risks for cancers of the stomach, gastric, colon, esophagus, endometrial and breast. Large data set from southern European populations showed an inverse association between the frequency of use of allium vegetables and the risk of several common cancers as well as benign prostatic hyperplasia.
The reduced risk of prostate cancer associated with allium vegetables was independent of body size, intake of other foods, and total calorie intake and was more pronounced for men with localized than with advanced prostate cancer.
Several epidemiological observations and a number of laboratory studies have indicated anti-carcinogenic potential of garlic, which has been traditionally used from time immemorial for varied human ailments in different parts of the globe. Hence, in recent years, extensive research has been conducted on the anti-carcinogenic potential of allium vegetables and their constituents, viz., allyl sulfides and flavonoids (particularly quercetin which is present abundantly in onion) resulting in mounting evidence that garlic extracts possess significant anti-cancer actions.
Epidemiological studies have shown a dose-dependent benefit of garlic in several types of cancers. In tumor-bearing mice, significant anti-tumor effects of aged black garlic extracts (ABGE) such as growth inhibition of inoculated tumors were observed. Further investigation of serum superoxide dismutases, glutathione peroxidase, IL-2 and the increased indices of spleen and thymus indicated that the anti-cancer action of ABGE may be partly due to its anti-oxidant and immuno-modulative effects.
Garlic components have been found to block covalent binding of carcinogens to DNA, enhance degradation of carcinogens, have anti-oxidative and free radical scavenging properties and to regulate cell proliferation, apoptosis and immune responses. There are a number of mechanisms at work which jointly are responsible for eliciting the anti-carcinogenic effects noted in laboratory studies in a wide range of experimental systems.
Sengupta et al (2004) in his review article reported that organo-sulfur compounds present in allium vegetables are considered to be responsible for the beneficial effects of these herbs. Several mechanisms have been proposed to explain the cancer- preventive effects of these compounds including inhibition of mutagenesis, modulation of enzyme activities and inhibition of DNA adduct formation, free-radical scavenging, and effects on cell proliferation and tumor growth.
Miroddi et al. (2011) found the oil-soluble sulfur compounds to be responsible for anti-cancer effects exerted through multiple mechanisms such as: inhibition of metabolic carcinogenic activation, arrest of cell cycle, anti-oxidant and pro-apoptotic action. Kim et al (2012) clearly indicated that hexane extracts of garlic cloves-induced ROS are key mediators of mitochondrial membrane potential collapse, which leads to the induction of apoptosis, followed by caspase activation. However, further research is recommended to support these findings.
2. Essay on Garlic (As an Anti-Cognitive-Impairment):
Aged garlic extract (AGE) supplementation to senescence-accelerated-prone mouse 8 (SAMP8) from 2 months of age markedly improved the learning deficits of SAMP8 in the Morris water maze test and prevented the decrease in survival ratio. Chronic ingestion of AGE prevented this shrinkage in the frontal cerebrum and kept the brain size at the control level indicating that AGE has an anti-ageing effect on the senescence-accelerated Mouse.
S-allylcysteine, a major thioallyl compound present in aged garlic extract was found to be responsible for significant attenuation of the memory deficit and age- related changes of senescence-accelerated mice. Feeding of aged garlic extract prevented deterioration of hippocampal based memory tasks in mice, suggesting that aged garlic extract has a potential for preventing progression of Alzheimer’s disease.
Haider et al. (2008) observed a significant improvement in memory function in garlic-treated rats in the passive avoidance test. Moreover, increased brain 5-hydroxytryptamine levels were associated with improved cognitive performance.
3. Essay on Garlic (As an Anti-Diabetic Foods):
Garlic has been used safely since ancient times as both food and medicine in human populations for several clinical conditions. Its usage as a hypo-lipidemic agent is more popular. But, garlic also plays a beneficial role in diabetes. Several mechanisms were elucidated to explain the role of garlic in diabetes. Garlic was thought to increase hepatic metabolism, insulin release from pancreatic beta cells and/or exhibit insulin sparing effect.
Aqueous homogenate of garlic (10 ml/kg/day) administered orally to sucrose fed rabbits (10 g/kg/day in water for two months) significantly increased hepatic glycogen and free amino acid content, decreased fasting blood glucose, and triglyceride levels in serum in comparison to sucrose controls. Allicin, a sulfur-containing compound is responsible for the pungent odour of garlic and it has been shown to have significant hypoglycaemic activity.
S-allyl cystein sulfoxide (SACS), the precursor of allicin and garlic oil controlled lipid peroxidation better than glibenclamide and insulin. It also improved diabetic complications. SACS also stimulated in vitro insulin secretion from beta cells isolated from normal rats. Garlic was able to reduce blood glucose significantly compared with the control group thus further reiterating the benefit of garlic in diabetes.
In addition to fresh garlic, fermented form of the spice was also found to exhibit several therapeutic benefits. Yeast (Saccharomyces cerevisiae)-fermented aged black garlic (FBG) exhibited potent anti-oxidative effects. Jung et al. (2011b) suggested that the bioactivities of black garlic can be improved by yeast fermentation as FBG showed favourable hepato-protective, nephro-protective, hypo-lipidemic, and anti-obesity effects compared with the control, but no hypoglycaemic effects.
Fermented Garlic also prevented the risk factors of CVD among diabetics. Regular and prolonged use of therapeutic amounts of aged garlic extracts lowered blood homocysteine levels and showed prevention of some complications of diabetes mellitus. Padiya et al. (2011) observed significant (p < 0.05) reduction in body weight gain and serum glycated hemoglobin levels in fructose fed rats after garlic administration.
The anti-oxidant property of garlic is an added advantage to diabetics in the prevention of metabolic syndrome. Administration of raw garlic homogenate normalized both hepatic TBARS and GSH levels and thus concluded that raw garlic homogenate is effective in improving insulin sensitivity while attenuating metabolic syndrome and oxidative stress in fructose-fed rats. El-Demerdash et al. (2005) reported a cumulative effect of garlic and onion juices on oxidative stress and hyperglyceamia, and consequently they also alleviated liver and renal damage caused by alloxan induced diabetes.
Consumption of garlic along with hypoglycaemic medications was proved to potentiate the action of the drug while contributing its own benefits. According to Ashraf et al. (2011) garlic is a good supplement in the management of patients with diabetes and hyper-lipidemia as combination of garlic (300 mg) tablet with typical anti-diabetic medicine (Metformin 500 mg) has shown to improve glyceamic control. In addition, there was a considerable decrease in mean total cholesterol and triglycerides and a significant increase in HDL cholesterol as compared to placebo group (Metformin 500 mg alone).
4. Essay on Garlic (As an Anti-Fertility Foods):
Garlic bulbs have been reported to have abortifacient and emmenagogic properties. It has been reported that garlic powder or crude garlic preparations impaired testicular and male reproductive tract functions. Moreover, garlic metabolites such as diallyl trisulfide have been reported to have spermicidal effects.
The mechanisms of garlic action on male reproduction function, and particularly on spermatogenesis, however, remain unknown. Crude garlic consumption for one month reduced testosterone secretion and altered spermatogenesis at 10 per cent, 15 per cent and 30 per cent doses. Hammami et al. (2009) showed that feeding with crude fresh crushed garlic has inhibitory effects on Leydig steroidogenic enzyme expression and Sertoli cell markers.
These alterations might induce germ cell death (spermatocytes and spermatids) via an apoptotic process. According to Abdelmalik (2011), the testicular apoptosis with disruption in spermatogenesis following chronic crude garlic consumption could be correlated with two possible theories- being an anti-hyper-cholesterolemic agent, it might inhibit steroidogenesis resulting in a decrease in testosterone level and being one of the famous phytoestrogens it possibly has direct estrogen-like actions on adult male rat testes.
Hammami and El May (2012) have shown that garlic impairs testicular functions and has spermicidal effect on spermatozoa. The seminiferous tubules of rats treated with garlic fractions [one soluble in water (aqueous solution obtained by grinding and centrifugation) and the other one precipitated by ethanol (alcoholic precipitate obtained by precipitation of the aqueous solution)] showed an increased number of tubules deprived of spermatozoa. Hammami et al. (2013) reported through histological and molecular studies that one or several substances, soluble in water and precipitated by alcohol, impaired spermatogenesis.
5. Essay on Garlic (As an Anti-Hyperlipidemic Foods):
Garlic is reported to be a wonderful medicinal plant not only for its preventive characteristics in cardiovascular diseases, regulating blood pressure, lowering blood sugar and cholesterol levels. Evidence from numerous studies points to the fact that garlic can bring about the normalization of plasma lipids, enhancement of fibrinolytic activity, inhibition of platelet aggregation and reduction of blood pressure and glucose. Animal studies, and some early investigational studies in humans, have suggested possible cardiovascular benefits of garlic.
The cardiovascular effects of garlic have been documented in several older publications. However only in late 70’s Sainani et al. (1976) found that people who regularly eat larger amounts of garlic and onions have lower lipid and cholesterol levels than people who refrain from eating these.
Later, Agarwal (1996) demonstrated that garlic ingestion could bring down the blood cholesterol and triglyceride levels significantly. Prasad et al. (1997) found garlic to decrease aortic malondialdehyde and chemiluminescence although there was no change in serum cholesterol. This proves that garlic prevents the development of hyper-cholesterolemic atherosclerosis.
A Czech study by Sovova and Sova (2004) found that garlic supplementation reduced accumulation of cholesterol on the vascular walls of animals. Another study had similar results, with garlic supplementation significantly reducing aortic plaque deposits of cholesterol-fed rabbits. Another study by Durak et al. (2004) showed that supplementation with garlic extract inhibited vascular calcification in human patients with high blood cholesterol.
The known vasodilative effect of garlic is possibly caused by catabolism of garlic-derived polysulfide to hydrogen sulfide in red blood cells, a reaction that is dependent on reduced thiols in or on the RBC membrane. Hydrogen sulfide is an endogenous cardio protective vascular cell-signaling molecule.
The complete depression of cholesterol synthesis by diallyl disulfide, diallyl trisulfide, and dipropyl disulfide was found to be associated with cyto-toxicity by Liu and Yeh (2000) as indicated by marked increase in cellular LDH release. Judging from maximal inhibition and IC50 (concentration required for 50 per cent of maximal inhibition), S-allyl cysteine, S-ethyl cysteine, and S-propyl cysteine are equally potent in inhibiting cholesterol synthesis.
The cholesterol lowering effect was higher in rats fed raw garlic fractions and extracts. LDL decreased significantly with respect to the hyper-cholesterolemic groups fed with raw or frozen. However, HDL was found to increase in those treated with frozen fractions and extracts.
Chang et al. (2011) reported that treatment of Garlic oil significantly inhibits the up-regulation in MAPK and IL-6/MEK5/ERK5 signaling pathways in the diabetic rat hearts, reducing the levels of cardiac pathologic hypertrophy markers such as ANP and BNP, and improving the cardiac contractile function. His study demonstrated that garlic oil is a potential cardio-protective agent from diabetic cardio-myopathy.
Rahman (2007), Chan et al. (2007), Borrelli et al. (2007), Steiner and Lin (1998) have found garlic to reduce platelet aggregation and hyper-lipidemia. However, a randomized clinical trial funded by the National Institutes of Health (NIH) in the United States and published in the Archives of Internal Medicine in 2007 found that the consumption of garlic in any form did not reduce blood cholesterol levels in patients with moderately high baseline cholesterol levels.
On reviewing ten studies Alder etuil. (2003) found 6 of them to be effective. The average drop in total cholesterol was 24.8 mg/dL (9.9 per cent), LDL 15.3 mg/dL (11.4 per cent), and triglycerides 38 mg/dL (9.9 per cent). The overall average MQI score was 39.6 per cent (18 per cent – 70 per cent). Major shortcomings of many of the RCTs included short duration, lack of power analysis and intention to treat analysis, as well as lack of control of diet as a confounding variable.
Recently, it has been observed that aged garlic extract, but not the fresh garlic extract, exhibited radical scavenging activity. Just how much garlic should be consumed to achieve any health benefits is unknown. It takes at least 10 cloves to inhibit blood clotting to the same degree as a daily aspirin. Also, practitioners disagree as to whether cooked or dried garlic confers the same benefits imparted by eating it raw.
The mean difference in reduction of total cholesterol between garlic-treated subjects and those receiving placebo (or avoiding garlic in their diet) was – 0.77 mmol/1 (95 per cent CI: -0.65, – 0.89 mmol/l). These changes represent a 12 per cent reduction with garlic therapy beyond the final levels achieved with placebo alone. Dried garlic powder preparations also significantly lowered serum triglyceride by 0.31 mmol/l compared to placebo.
Primary hepatocyte cultures as used in the present study have been proven useful as tools for screening the anti-cholesterogenic properties of garlic principles. Gebhardt (1991) demonstrated that water-soluble garlic extracts diminish hepatic cholesterol biosynthesis, thus contributing to the reduction of blood cholesterol the main target site being HMGCoA-reductase.
Gebhardt and Beck (1996) demonstrated that different garlic-derived organosulfur compounds interfere differently with cholesterol biosynthesis and, thus, may provoke multiple inhibition of this metabolic pathway in response to garlic consumption. Diallyl disulfide, diallyl trisulfide and dipropyl disulfide depressed cholesterol synthesis by 10 to 25 per cent at low concentrations (< or = 0.5 mmol/l), and abolished the synthesis at high concentrations (> or = 1.0 mmol/L).
The cholesterol-lowering effects of garlic extract stem in part from inhibition of hepatic cholesterol synthesis by water-soluble sulfur compounds, especially S-allylcysteine, whereas the triacylglycerol-lowering effect appears to be due to inhibition of fatty acid synthesis. According to Liu and Yeh (2000; 2001) S-allyl cysteine, S-ethyl cysteine, and S-propyl cysteine inhibit lipid biosynthesis in cultured rat hepatocytes, and they further suggest that these S- alkyl cysteines of garlic impair triglyceride synthesis in part due to decreased de novo fatty acid synthesis.
Matsuura (2001) found that the saponin fractions from garlic lowered plasma total and LDL cholesterol concentrations without changing HDL cholesterol levels in a hyper-cholesterolemic animal model. Several steroid saponins occur in both garlic and aged garlic extract. These results suggest that special consideration should be given to steroid saponins, as well as organosulfur compounds, in biological and pharmacologic studies of garlic and its preparations.
The mechanisms involved in the cardio-protective effects of polyphenols are numerous and include anti-oxidant, vasodilator, anti-inflammatory, anti-fibrotic, anti-apoptotic arid metabolic. Most importantly, recent experimental data demonstrate that polyphenols can exert its cardio-protective effect via the activation of several powerful pro-survival cellular pathways that involve metabolic intermediates, micro RNAs, sirtuins and mediators of the recently described reperfusion injury salvage kinases (RISK) and survivor activating factor enhancement (SAFE) pathways.
Monascus Garlic Fermented Extract attenuates hyperlipidemia, suggesting that MGFE is a potent agent for preventing arteriosclerotic diseases. The intake of garlic fermented with Monascus pilosus decreased triglyceride and cholesterol in serum with no appreciable adverse effects in normal to mildly hyper-lipidemic individuals, suggesting that it may be effective to improve and prevent the metabolic syndrome.
Cholesterol-induced steatosis leads to a weakened antioxidant defence system and causes peroxidation in the hepatic tissue. Arhan et al. (2009) established that treatment with aqueous garlic extract resulted in a significant increase in antioxidant potential and partly eliminated peroxidation damage in the hepatic tissue. Additionally, the extract reduced the cholesterol levels of blood and hepatic tissues significantly. The histological evaluations confirmed the same.
6. Essay on Garlic (As an Anti-Inflammatory Foods):
Garlic is well known for its anti-oxidant and anti-inflammatory properties. In vitro studies have shown that high concentrations of garlic can decrease cytokine production in endothelial cells. Aged garlic extract (ARG) was shown to increase nitric oxide production and decrease the output of inflammatory cytokines from cultured cells in 15 men with coronary artery disease. Compared to fresh raw garlic, aged red garlic was found to possess higher antioxidant effects. Park et al. (2012a) showed that ARG extract has potential effects on prevention and treatment of acute inflammatory lung injury.
Sulfur compounds isolated from garlic exert anti-inflammatory properties. Topical application of thiacremonone, a sulphur compound from garlic suppressed the 12-O-tetradecanoylphorbol-13-acetate-induced ear edema; the carrageenan and mycobacterium butyricum-induced inflammatory and arthritic responses as well as expression of iNOS and COX-2, in addition to NF-kappaB DNA-binding activity. Further in vitro study showed inhibition of lipo-polysaccharide-induced nitric oxide (NO) production, and NF-kappa B transcriptional and DNA binding activity in a dose dependent manner by thiacremonone. Thus, Ban et al (2009) recommended that thiacremonone of garlic could be a useful agent for the treatment of inflammatory and arthritic diseases.
Lee et al (2012) identified anti-inflammatory sulfur-containing compounds from garlic, and their chemical structures. They were Z- and E-ajoene and oxidized sulfonyl derivatives of ajoene. The sulfur compounds inhibited the production of nitric oxide and prostaglandin E-2, and the expression of the pro-inflammatory cytokines, tumor necrosis factor-α, interleukin-1β, and interleukin-6 in lipo-polysaccharide (LPS) – activated macrophages.
Dkhil et al (2011) studied the effect of garlic on mice infected with E. papillata and proved that garlic treatment significantly attenuated inflammation and injury of the liver. Administration of garlic and onion to fructose-fed rats reduced oxidative stress, increased eNOS activity, and also attenuated vascular cell adhesion molecule- (VCAM-1) expression.
Chronic bacterial prostatitis (CBP), which is characterized by recurrent urinary tract infection (UTI), persistence of pathogenic bacteria and evidence of inflammation in the prostatic secretions, is one of the most common causes of relapsing UTI in men. Sohn et al. (2009) observed that the garlic significantly decreased the bacterial growth and improved prostatic inflammation and the garlic plus ciprofloxacin group showed better results than the ciprofloxacin group alone suggesting a synergistic effect of garlic with the antibiotic, ciprofloxacin.
7. Essay on Garlic (As an Antimicrobial Foods)
Louis Pasteur in 1858, observed garlic’s anti-bacterial activity. It was used as an antiseptic to prevent gangrene during World War I and World War II. It is an effective antimicrobial agent against bacterial, viral, fungal, protozoal and parasitic infections. While enhancing the immune system, garlic also showed anti-tumoral and anti-oxidant features.
It may also play an important role in the ecological control of pathogenic micro-organisms in nature. Garlic is renowned for the compound allicin, which exerts anti-bacterial and anti-fungal effects. It is effective in curing common diseases such as dysentery, diarrhea, tuberculosis etc. Garlic oil was found to have significant inhibition of microbial growth on fresh-cut tomatoes.
Garlic extract showed greater activity against Gram-positive organisms, Gram- negative organisms and fungi as compared to the extract of onion. Thirty strains of mycobacteria, consisting of 17 species, were inhibited by various concentrations of garlic extract incorporated in Middle brook 7H10 agar. The concentration required ranged from 1.34 mg/ml to 3.35 mg/ml of media. Six strains of M. tuberculosis required a mean inhibitory concentration of 1.67 mg/ml of media.
The anti-fungal activity of six fractions derived from garlic in an in vitro system showed that Ajoene had the strongest activity among all other fractions. The growth of both A. niger and C. albicans was inhibited by ajoene at less than 20 μg/ml.
Steroid saponins have been found to have some interesting biological and pharmacologic activities including anti-fungal, anti-bacterial, anti-inflammatory and hypo-cholesteremic influences. Plants of the genus Allium are known for their production of steroid saponins, as well as organ sulfur compounds. The genuine saponin proto-eruboside- B was inactive against C. albicans. Interestingly, when raw garlic bulbs are crushed, the enzymatic conversion of compound 1 into compound 2 by ß-glucosidase is similar to the conversion of alliin into allicin by alliinase, and both end-products exhibit anti-fungal properties.
Garlic destroys the micro-organisms E. coli and S. albus. However, the antibacterial effect of garlic decreases after a 30-minute exposure to heat. In addition to garlic, members of the Allium genus such as onions, leeks, shallots and chives show antibiotic effects. Bachrach et al. (2011) demonstrated that planktonic growth of the tested Gram-negative periopathogenic species Aggregatibacter actinomycetemcomitans and Fusobacterium nucleatum was inhibited by a minimum allicin concentration of 300 µg/mL. P. gingivalis, an anaerobic, Gram-negative pathogen and the bacterium most associated with chronic periodontitis, demonstrated the lowest sensitivity to allicin (2,400 µg/mL). A gingipain-inactivated mutant demonstrated high sensitivity to allicin (< 300 µg/mL), revealing that gingipains confer resistance to allicin.
Fresh extract of garlic showed greater antimicrobial activity as compared to similar extracts of onion. At comparable concentrations, freshly reconstituted dehydrated onion and garlic powders exhibited that growing cultures of E. coli were as susceptible to garlic, but apparently more resistant to onion, than were those of S. typhimurium.
Although garlic has been used for its medicinal properties for thousands of years, investigations into its mode of action are relatively recent. Garlic showed antimicrobial activity against Mutans streptococci and other oral microorganisms, and hence, might be an alternative to chlorhexidine.
Periodontal disease is the collective term given to a variety of inflammatory conditions in the tissue that supports and secures the teeth to the jawbone. The inflammatory response is to bacterial products and/or bacteria that enter the tissue from the dental plaque.
The dental plaque is a complex microbial community containing over 190 different taxa that exist on the tooth surfaces. In periodontitis, the majority of the plaque bacteria are anaerobes including the black pigmented bacteroides species and motile forms such as spirochetes.
Garlic extract is effective against S. mutans when tested both in vitro and in vivo. Thus garlic extract mouth rinse might be used as an effective remedy in the prevention of dental caries. According to Bakri and Douglas (2005), Time-kill curves for S. mutans and P. ginigvalis, showed that killing of the latter started almost immediately, whereas there was a delay before S. mutans was killed.
The garlic extract also inhibited the trypsin-like and total protease activity of P. gingivalis by 92.7 per cent and 94.88 per cent, respectively indicating that garlic extract inhibits the growth of oral pathogens and certain proteases and so may have therapeutic value, particularly for periodontitis. All isolates, MDR and non-MDR of S. mutans were sensitive to garlic extract. Considering these beneficial effects of garlic, mouthwashes or toothpastes containing optimum concentration of garlic extract could be used for prevention of dental caries.
In vitro study by Groppo et al. (2007) revealed the Minimum inhibitory concentration ranged from 0.5 to 32.0 mg ml (-1) for White garlic extract and from 8 to 64.0 mg ml (-1) for Purple garlic. Minimum bactericidal concentration ranged from 1.0 to 128.0 ml (-1) and from 8.0 to 128.0 ml (- 1) regarding white and purple garlic respectively. In vivo experiment showed that 2.5 per cent garlic mouthwash solution had good antimicrobial activity against mutans streptococci and oral microorganisms. The reduced salivary levels of streptococci were maintained even after 2 weeks after mouthwash discontinued.
There is a need for alternate solutions to decrease the burden of drug resistance and cost in the management of diseases. The use of garlic against emergence of multidrug resistant (MDR) -TB may be of great importance regarding public health. The minimum inhibitory concentration of garlic extract ranged from 1 to 3 mg/ml; showed inhibitory effects against both non-MDR and MDR M. tuberculosis isolates.
Helicobacter pylori is a bacterium implicated in the etiology of stomach cancer and ulcers. The incidence of stomach cancer is lower in populations with a high intake of allium vegetables, probably due to the sensitivity of H. pylori to garlic. Sivam (2001) has demonstrated in vitro that H.pylori, including the antibiotic-resistant strains is susceptible to garlic extract at a fairly moderate concentration.
Aqueous extract of garlic and onion showed significant growth inhibition against Gram-positive organisms, Gram-negative organisms and fungi. The activity of the garlic extract on the mouth flora of volunteers was investigated by Elnima et al (1983) and they observed a drastic reduction in the number of oral bacteria by a mouth wash containing 10 per cent garlic in quarter Ringer solution.
In addition to its health benefits in humans, garlic has also been found to be an efficient antimicrobial agent in other species. The protozoan parasite Eimeria causes coccidiosis which leads to enormous economic losses particularly in poultry farms.
Toulah and Al-Rawi (2007) found that treatment of E. stiedae in infected garlic resulted in regaining of normalcy in the liver, whereas the untreated group continued to show histopathological alterations in liver tissue, marked cytoplasmic vacuolations in hepatocytes with clear signs of karyolysis, and dilatation of sinusoids with increase in Kupffer cells. Dkhil et al. (2011) reported that garlic counteracted the E. papillata induced loss of glutathione and the activities of catalase and superoxide dismutase and significantly attenuated inflammation and injury of the liver induced by the infection.
Spironucleus is a genus of small, flagellated parasites, many of which can infect a wide range of vertebrates and are a significant problem in aquaculture. Following the ban on the use of metronidazole in edible fish due to toxicity problems, no satisfactory chemotherapies for the treatment of spironucleosis are currently available.
Millet et al. (2011) demonstrated that of all the allium-derived compounds from garlic, the ajoene-free mixture of dithiins and thiosulfates was the most effective with a minimum inhibitory concentration (MIC) of 107 µg/ml(-1) and an inhibitory concentration at 50 per cent (IC(50 per cent)) of 58 µg ml(-1). These concentrations are much higher than those reported to be required for the inhibition of most bacteria, protozoa and fungi previously investigated, indicating an unusual level of tolerance for allium-derived products in S. vortens.
8. Essay on Garlic (As an Anti-Obesity Foods):
Kim and Kim (2011) evaluated the effectiveness of garlic on alleviating obesity. Garlic affected the down regulation of expression patterns of epididymal adipose tissue genes such as peroxisome proliferator-activated receptor γ (PPARγ), acetyl CoA carboxylase, adipose specific fatty acid binding protein (aP2), and glycerol-3- phosphate dehydrogenase (GPDH).
These results suggest that garlic may have a potential benefit in preventing obesity. They also found the administration of the same to improve the body weight gain and dyslipidemia through the suppression of body fat and alteration in lipid profiles and antioxidant defense system. The anti-obesity effects of garlic were at least partially mediated via activation of AMPK, increased thermogenesis, and decreased expression of multiple genes involved in adipogenesis.
Lee et al. (2012) and Joo et al. (2013) investigated the effect of hot water extract of garlic (WEG) and high hydrostatic pressure extract of garlic (HEG) on obesity in rats fed a high-fat (HF) diet. Supplementation with HEG significantly reduced body weight gain and adipose tissue mass compared to those in the HF group, whereas WEG did not. Serum levels of triglycerides, total cholesterol, and LDL-cholesterol were also decreased in the HEG supplemented group compared to those in the HF group.
Seo et al. (2012) reported that AGE supplementation and exercise alone have anti-obesity, cholesterol lowering, and anti-inflammatory effects, but the combined intervention is more effective in reducing weight gain and triglycerides levels than either intervention alone.
9. Essay on Garlic (As an Anti-Oxidant Foods):
Garlic is known to possess preventive properties in cardiovascular diseases, regulating blood pressure, lowering blood sugar and cholesterol levels, anti-platelet activities, and thromboxane formation. It is also effective against bacterial, viral, fungal and parasitic infections, enhancing the immune system and having anti-tumoral and anti-oxidant features.
Garlic contains a number of chemicals such as sulfur compounds (allicin, alliin and agoene), volatile oils, enzymes (allinase, peroxidase and miracynase), carbohydrates (sucrose and glucose), minerals (selenium), amino acids (cysteine, glutamine, isoleucine and methionine) which help to protect cells from the ills of free radicals, bioflavonoids such as quercetin and cyanidin, allistatin I and allistatin II, and vitamins C, E and A which help in protecting from oxidative agents and free radicals.
Administration of garlic and onion to fructose-fed rats reduced oxidative stress, increased eNOS activity, and also attenuated vascular cell adhesion molecule-(VCAM-1) expression. These results provide new evidence showing the anti-inflammatory and anti-oxidant effect of these vegetables. Butt et al. (2009) emphasized garlic’s ability to ameliorate oxidative stress, core role in cardiovascular cure, chemo-preventive strategies and prospective effect as immune booster.
Aged garlic extract exerts anti-oxidant action by scavenging Reactive Oxygen Species, enhancing the cellular anti-oxidant enzymes superoxide dismutase, catalase and glutathione peroxidase, and increasing glutathione in the cells. Aged garlic extract also inhibits lipid peroxidation, reducing ischemic/reperfusion damage to the endothelial cells by the oxidized molecules, which, otherwise contributes to atherosclerosis.