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International Journal of Applied and Basic Medical Research logoLink to International Journal of Applied and Basic Medical Research
. 2026 Feb 20;16(1):43–50. doi: 10.4103/ijabmr.ijabmr_318_25

Hypoglycemic, Hypolipidemic, and Antioxidant Effect of Allium sativum in Daily Consumable Dosage in High-fat Diet and Streptozotocin-induced Type 2 Diabetic Model of Rats

Ayu Singh 1, Ratna Pandey 1, Kumar Sarvottam 1,2,✉, Anchal Tripathi 3
PMCID: PMC12970756  PMID: 41810276

Abstract

Purpose:

The purpose of this study was to determine the effects of daily consumable dosage of garlic on type 2 diabetic male rats.

Materials and Methods:

Charles foster male rats were randomly divided into four groups: control group, obese, fed with high-fat diet (HFD), diabetic fed with HFD followed by intraperitoneal streptozotocin treatment-35 mg/kg body weight; and diabetic rats fed with garlic (60 mg/day). Anthropometric and blood parameters were measured at 7th, 14th, 21st, and 28th days.

Results:

The food intake, water consumption, and body weight were significantly (P ≤ 0.05) reduced in the garlic-treated rats as compared to the diabetic rats on the 28th day. After 28th day, the levels of triglyceride and total cholesterol declined significantly (P ≤ 0.05), while high-density lipid levels increased in the garlic-treated group as compared to the diabetic group (P ≤ 0.05). Blood glucose levels were significantly reduced at 30 min and 120 min of oral glucose tolerance test in garlic garlic-treated group. The activity of superoxide dismutase, catalase (CAT), glutathione reductase, glutathione-S-transferase, and reduced glutathione (GSH) were significantly higher in the garlic-treated group compared to the diabetic group (P ≤ 0.05) on the 28th day. Glutathione peroxidase activity and lipid peroxidase level were reduced in the garlic-treated group compared to the diabetic group (P ≤ 0.05).

Conclusions:

Garlic reduced food and water intake, body weight, oxidative stress as well as improved lipid and glucose metabolism, suggesting its effectiveness for diabetes and overall metabolic health in a daily consumable diet.

Keywords: Allium sativum, antioxidant, high fat diet, type 2 diabetes

Introduction

The global public health burden of type 2 diabetes (T2D) has escalated at an alarming pace in the last few decades, posing a significant challenge to the healthcare system worldwide.[1] Uncontrolled T2D can lead to microvascular and macrovascular complications, potentially resulting in life-threatening conditions.[2] One of the key risk factors for diabetes is improper dietary habits along with sedentary lifestyle.[3,4]

Evidences suggest that dietary interventions, including the use of certain herbs and spices, may provide a promising strategy for managing this metabolic disorder.[5] For decades, traditional medicine has utilized herbs and plant extracts such as garlic, coriander, Tulsi, black mustard, and kalonji to manage diabetes, heart disease, and inflammation by regulating blood sugar levels and improving insulin sensitivity.[6] In Indian kitchens, many spices are regularly used in cooking and also possess medicinal properties. Among these, garlic stands out as a potential candidate for promoting health benefits, including anti-obesity, anti-oxidant effects via glucose and lipid homeostasis as well as anti-inflammatory properties.[7,8] The bioactive compounds in garlic, such as allicin, diallyl disulfide, S-allyl cysteine, ajoene, and flavonoids, contribute to these properties.[9,10] Its therapeutic and pharmacological effects are well documented, including improvements in lipid profile and endothelial function reduction in blood glucose levels, and lowered blood pressure while reducing the arterial stiffness.[1,11,12] Studies at the molecular level reveal that persistent hyperglycemia triggers the production of advanced glycated end product (AGEs) and increased oxidative stress by generating excess reactive oxygen species (ROS) and free radicals, leading to cellular damage, lipid peroxidation, protein oxidation, and deoxyribonucleic acid damage via mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase signalling pathways.[13]

Garlic supports glycemic control through its antioxidant compounds, such as allicin and alliin that mitigate oxidative stress. Alliin (0.1 mg/mL) enhances glucose homeostasis, insulin sensitivity, and lipid profiles but does not prevent adiposity.[14] Study found that garlic extract (500 mg/kg body weight) significantly reduced fasting blood glucose (FBG) in insulin-resistant rats after 8 weeks but did not affect insulin resistance index or glucose tolerance.[1] Garlic oil (50 mg/kg/day) exhibits anti-obesity effects in obese rats.[15] A 5% freeze-dried garlic diet enhances antioxidant enzyme activity (superoxide dismutase [SOD], catalase [CAT], glutathione peroxidase [GPx]) in liver homogenates,[16] while 500 mg/kg of garlic aqueous extract elevates total serum antioxidant levels in streptozotocin (STZ)-induced diabetic rats.[17] Mechanistically, garlic may enhance insulin mRNA transcription and synthesis in pancreatic tissues[18] and improve glucose metabolism via Akt pathway activation.[19]

Although the therapeutic potential of higher garlic dosages and its bioactive ingredients is recognized, research on the protective effects of whole garlic at a consumable dosage in T2D rat model remains unexplored. Therefore, the present study aims to investigate the impact of garlic administration in consumable dosage by assessing lipid profile, anthropometric parameters, and oxidative stress markers in the T2D rat model. The findings will contribute to a more comprehensive understanding of the therapeutic potential of the whole form of garlic and developing strategies for improving metabolic health.

Materials and Methods

Animals

The experimental animal, Charles Foster rats of average weight (150 ± 10 g) and 8 weeks old, were procured from the animal house, of the Institute. Animals were maintained under standard conditions of temperature (23°C ± 2°C) and humidity (50% ± 10%) with an alternating 12 h light/dark cycle. The animals were given free access to tap water and fed with a chow diet and a high-fat diet (HFD). All the experiments were carried out according to the CPCSEA guidelines of the Institutional Animal Ethical Committee (IAEC) (Letter no.-Dean/2023/IAEC/6201 date October 23, 2023).

Induction of type 2 diabetes

The rats were initially fed with HFD for 2 weeks following which they received an intraperitoneal injection of STZ; 35 mg/kg dissolved in sodium citrate buffer (pH 4.5) for the induction of T2D.[20] Feeding was stopped 12 h before STZ administration and testing of the glucose level. Five days postinjection, blood was collected from the retro-orbital plexus. Rats with FBG levels >200 mg/dL were considered diabetic and selected for further experiments.

Preparation of garlic solution

The garlic (Allium sativum) dosage was determined on the basis of the average daily intake of garlic reported for the Indian population, while accounting for the basal metabolic rate of rats. According to the national dietary data, an average Indian adult consumes approximately 3.88 g of garlic per day.[21] This human intake was converted to an equivalent rat dose using the standard body surface area allometric scaling method. Applying the human-to-rat Km factor ratio (37/6) yielded a rat-equivalent dose of approximately 400 mg/kg. For a 150 g rat, this corresponds to a daily administration of 60 mg/day. Accordingly, garlic was administered at 60 mg/day, representing a physiologically relevant, human-equivalent dietary dose rather than a pharmacological or supra-physiological level. For achieving this goal, fresh garlic bulbs were procured from a local market in Varanasi, India, in July 2023. For preparation of solution, 6 g of garlic bulbs were crushed and mixed thoroughly with 100 mL of drinking water, and the resulting suspension was stored at 4°C until use. A 1 mL aliquot of this freshly prepared garlic solution was administered once daily by oral gavage for 28 days. The conversion formula is:

Animal dose(Inline graphic)=Human dose(Inline graphic)×(Human km/Rat km)

Experimental design

The rats were distributed randomly into four groups n = 6, as explained:

  • Control group: Rats fed upon normal chow diet treated with sodium citrate buffer (pH = 4.5, 0.1 M)

  • Obese group: Rats fed upon HFD with sodium citrate buffer

  • Diabetic group: Rats fed upon HFD treated with STZ (35 mg/kg body weight dissolved in sodium citrate buffer)

  • Garlic treated group: Rats fed upon HFD with T2D received oral aqueous garlic solution (60 mg/day, gavage, 4 weeks).

The experimental period lasted for 28 days. The anthropometric parameters were studied at every 7-day interval. Blood samples were collected from the retro-orbital plexus using a capillary tube and centrifuged at 2000 rpm to separate the serum for further analysis. Biochemical estimation of antioxidant parameters was conducted at 7th day, 14th day, 21st day, and 28th day while the lipid profile was analysed at the end of the 28d.

Measurement of anthropometric parameters

Body weight and food intake (narcissistic personality disorder and HFD) were measured using the weighing machine (Aliston Digital weighing scale with least count 0.1 g (weight limit 10 kg). A 300 mL polycarbonate water bottle with a measuring mark was used to measure water consumption. Weight gain in percentage was also calculated.

Measurement of fasting blood glucose and oral glucose tolerance test

FBG was assessed after a 12-h fasting period at every 7-day interval using a standard glucometer (Dr. Morepen GlucoOne Blood Glucose Monitor Model BG-03). The level was expressed as milligrams per deciliter. The oral glucose tolerance test (OGTT) was conducted by administering a 20% glucose solution (2 g/kg body weight), and blood glucose levels were then measured at 0, 30 min, 60 min, 90 min, and 120 min postglucose administration.

Measurement of lipid parameters

The lipid parameters were evaluated at the end of 28th day. Blood samples were collected from the retro-orbital sinus of fasting rats and transferred into ethylenediaminetetraacetic acid (EDTA) tubes. The samples were then centrifuged at 3500 rpm for 10 min to separate the serum, which was used for lipid analysis. Serum triglycerides (TG), total cholesterol (TC), and high-density lipid (HDL) cholesterol levels were measured using the Autospan Liquid GoldTM kit. Very low-density lipid and low-density lipid cholesterol levels were calculated using standard formulas.

Biochemical estimation of antioxidant parameters

A 500 mg wet weight of liver tissue was homogenized in RIPA buffer and centrifuged at 18,000 × g for 30 min at 4°C. The resulting supernatant was collected, and the protein content was estimated using Lowry et al. method.[22]

Superoxide dismutase activity

The activity of SOD was estimated by using the modified spectrophotometric method based on nitrite formation by superoxide radicals as described by Das et al., 2000.[23] The reaction mixture contained 110 mL of 50 mM phosphate buffer (pH 7.4), 75 µl of 20 mM L-methionine, 40 µl of 1% (v/v) Triton-X-100, 75 µl of 10 mM hydroxylamine hydrochloride, and 100 µl of 50 µM EDTA, to which the sample was added and incubated at 37°C. After 10 min, 80 µl of 50 µM riboflavin was introduced, and the mixture was exposed to light for another 10 min. The reaction was stopped with freshly prepared 1 mL of Griess reagent, and absorbance was recorded at 543 nm.

Catalase activity

CAT activity was determined by measuring the decomposition of hydrogen peroxide as described in the Worthington Enzyme Manual.[24] The sample (100 µl) was incubated with 500 µl of 60 mM hydrogen peroxide, 700 µl of 0.05 M phosphate buffer (pH 7.1), and 200 µl of distilled water. The decomposition of hydrogen peroxide was monitored by measuring absorbance at 240 nm at 30-second intervals for 3 min.

Glutathione-S-transferase activity

Glutathione S-transferase activity was measured spectrophotometrically using 1-chloro-2,4-dinitrobenzene (CDNB) as a substrate, following the method of Habig et al., 1976.[25] The reaction mixture included 1 mL of 0.1 M phosphate buffer (pH 6.5), 1.7 mL of distilled water, and 100 µl of 1 mM CDNB. 100 µL of the sample was added to the reaction mixture and incubated at 37°C for 5 min. After incubation, 100 µl of 30 mM reduced glutathione was added, and absorbance was recorded at 340 nm.

Glutathione peroxidase activity

With modifications, GPx activity was estimated by measuring the decrease in reduced glutathione content after incubation with hydrogen peroxide.[26] The reaction mixture contained 550 μL of 50 mM phosphate buffer (pH 6.8), 400 μL of 4 mM EDTA, 200 μL of 10 mM sodium azide, 400 μL of 4 mM reduced glutathione (GSH), and 200 μL of 25 mM hydrogen peroxide, with the 50 μL sample incubated at 37°C for 10 min. The reaction was terminated with 200 μL of 10% trichloroacetic acid, centrifuged, and the supernatant was reacted with 0.08% of 5,5’ dithiobis (2-nitrobenzoic acid) reagent (DTNB), with absorbance recorded at 412 nm.

Glutathione reductase

Glutathione reductase (GR) activity was measured by monitoring the nicotinamide adenine dinucleotide phosphate (NADPH) oxidation, following the method of Carlberg and Mannervik, 1985.[27] The reaction mixture included 750 μL of 0.2 M potassium phosphate buffer (pH 7.0), 2 mM EDTA, 255 μL distilled water, 300 μL of 2 mM NADPH, and 75 μL of 20 mM oxidized glutathione. Twenty micro liters sample was added, and absorbance at 340 nm was recorded at 1-min intervals for 5 min.

Reduced glutathione content

Reduced glutathione content was estimated using Ellman’s reagent (DTNB) by measuring the yellow chromophore formed, as described by Ellman method.[28] One hundred micro liter of sample was mixed with 0.1 M sodium phosphate buffer (pH 7.0), 1 mM EDTA, 760 μL distilled water, and 40 μL of 0.04% DTNB, followed by a 5-min incubation. The absorbance was measured at 412 nm, and GSH concentration was determined using a standard curve.

Lipid peroxidation

Lipid peroxidation was assessed by measuring malondialdehyde levels using the thiobarbituric acid method.[29] Two hundred microliters sample was mixed with 8.0% sodium dodecyl sulphate, 1.5 mL of 20% acetic acid, 1.5 mL of 0.8% thiobarbituric acid, and 100 μL of 0.8% butylated hydroxytoluene, then heated at 95°C for 1 h and cooled to room temperature to develop a pink colour. The reaction mixture was cooled, centrifuged, and the absorbance of the supernatant was measured at 532 nm.

Statistical analysis

Data were expressed as mean ± standard error each experiment was repeated thrice for reproducibility. One-way ANOVA was used for graphical analysis and group comparisons. Tukey’s test was used for post hoc analysis. Statistical analyses were conducted using IBM SPSS Statistics for Windows (version 26.0; IBM Corp., Armonk, NY, USA), with the level of statistical significance set at P ≤ 0.05.

Results

Anthropometric parameters

The initial body weight (150 ± 10 g) in all groups is comparable as we mentioned in method section. Final body weight was significantly higher in obese group in comparison to other three groups (P ≤ 0.05). Garlic-treated group had significant (P ≤ 0.05) decrease in body weight in comparison to diabetic group. Similarly, weight gain in the obese group was significantly (P ≤ 0.05) higher than control, diabetic, and garlic treated groups. In garlic treated group, weight gain is significantly (P ≤ 0.05) lesser than diabetic group. Food consumption in the control and obese group was comparable (P = 0.222). Diabetic group had significant increase in food intake in comparison to control and obese group (P ≤ 0.05). Garlic treated group showed significant lesser food intake in comparison to diabetic group (P ≤ 0.05). Similarly, water intake in diabetic group was significantly higher than control and obese group (P ≤ 0.05). Garlic treated group showed significantly (P ≤ 0.05) reduced water intake compared to diabetic group [Table 1].

Table 1.

Body weight, weight gain percentage, food intake, and water consumption of rats

Control Obese Diabetic Garlic treated
Final body weight (g) 223.55±0.98a 265.68±3.72b 247.36±1.95c 214.31±1.22d
Weight gain (%) 32.72±0.31a 41.87±0.87b 38.85±0.47c 29.69±0.39d
Food intake (g/d) 15.23±0.30a 16.11±0.35a 20.31±0.33b 14.91±0.30a,#
Water consumption (ml/d) 22.46±0.88a 34.39±1.35b 51.87±1.48c 37.54±1.14d
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#Represent significant difference with obese group. Different letters show statistically significant differences (P≤0.05). Values represent mean±SE in all groups (n=6). SE: Standard error

Oral glucose tolerance test

FBG levels were significantly (P ≤ 0.05) higher in diabetic group compared to the control, obese groups and garlic treated group at the 28th day. At 30 min, 60 min, 90 min, and 120 min, blood glucose level was significantly (P ≤ 0.05) higher in diabetic group compared to other groups. At FBG, 30 min, and 120 min, glucose level significantly (P ≤ 0.05) declines in garlic treated group as compared to diabetic group but at 60 min and 90 min glucose level in garlic treated group and diabetic group were comparable (P = 0.063, 0.3 respectively) [Table 2].

Table 2.

Glucose level at fasting, 30 min, 60 min, 90 min, and 120 min at 28 days

At 28 days (mg/dL) Control Obese Diabetic Garlic treated
FBG 139.8±4.33a 139±5.22a 459.6±67.67b 233.6±45.57a
30 min 162.6±13.95a 193.8±15.33a 558.73±30.18b 311.5±40.96c
60 min 168.8±16.67a 205.4±13.44a 580.47±11.41b 428.8±74.54b
90 min 161.3±18.53a 184.2±7.25a 562.66±68.01b 357.7±72.95b
120 min 135.9±1.79a 185.8±8.65b 524.13±15.76c 220.6±66.01d
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Different letters show statistically significant differences (P≤0.05). Values represent mean±SE in all groups (n=6). SE: Standard error; FBG: Fasting blood glucose

Lipid profile

Obese group has significantly (P ≤ 0.05) higher level of TC and TG compared to control. Further, diabetic group had significantly (P ≤ 0.05) higher TC and TG level compared to obese group. Garlic treated group showed significant (P ≤ 0.05) decline in the level of TC and TG. Level of HDL was significantly (P ≤ 0.05) decreased in obese group and much (P ≤ 0.05) decreased in diabetic group compared to control. Garlic-treated group significantly (P ≤ 0.05) increased the level of HDL compared to diabetic group [Table 3].

Table 3.

Level of total cholesterol, triglyceride, and high-density lipid at 28 days

At 28 days Control Obese Diabetic Garlic treated
Cholesterol 111.32±0.74a 129.42±1.83b 169.55±1.25c 119.34±1.83d
TG 82.04±1.66a 113.074±1.46b 200.14±1.66c 123.85±1.44d
High density lipid 57.86±3.5a 37.37±1.79b 25.37±3.05c 50.94±0.36a
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Different letters show statistically significant differences (P≤0.05). Values represent mean±SE in all groups (n=6). SE: Standard error; TG: Triglyceride

Antioxidant parameters

A significant (P ≤ 0.05) decline in SOD activity was observed in the obese and diabetic groups as compared to control group from the 7th day to 28th day. However, the activity increased significantly (P ≤ 0.05) in the garlic-treated group, with the activity close to the control group at the end of 28th day in Figure 1a.

Figure 1.

Figure 1

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Effect of consumable dosage of garlic on the activity of (a) superoxide dismutase, (b) catalase, (c) glutathione reductase, (d) Glutathione-S-transferase, (e) glutathione peroxidase, (f) GSH content, and (g) lipid peroxidase in the serum of rattus norvagicus in control, obese, diabetic, and garlic treated groups (60 mg/day) at 7 day, 14 day, 21 day, and 28 day. Results are presented as mean ± standard error; n = 6. The data are analyzed by the one-way ANOVA followed by Tukey’s post hoc test. Bars followed by different letters show significantly different from each other (P ≤ 0.05)

Control and obese group have no significant difference in CAT activity at every point of time. Diabetic group has significant (P ≤ 0.05) decline the activity of CAT compare to the control group from 7th day to 28th day. CAT activity was significantly (P ≤ 0.05) increased in the garlic treated group compared to the diabetic group at 28th day in Figure 1b, indicating enhanced enzymatic detoxification of hydrogen peroxide.

GR activity followed a similar trend, at 7th day to 28th day GR activity was significant (P ≤ 0.05) decline in the obese and diabetic group. Garlic significant (P ≤ 0.05) increased enzyme activity compared to diabetic group at the 21st day. Activity of GR significant (P ≤ 0.05) increased and restored as control group at the 28th day in Figure 1c. Diabetic rats showed suppressed GR activity throughout the study.

Throughout the study, glutathione-S-transferase (GST) activity was significant (P ≤ 0.05) decline in the obese and diabetic group. GST activity was significantly (P ≤ 0.05) enhanced in garlic treated group at the 28th day, compared to diabetic group, which exhibited lower GST activity across all durations showing in Figure 1d.

GSH content was significant (P ≤ 0.05) decline in the obese, diabetic, and garlic treated group at the 7th day to 21st day. GSH content in garlic treated group was significantly (P ≤ 0.05) restored at 21st day, 28th day (P ≤ 0.05) compared to diabetic group showing in Figure 1e.

At 7th day till 28th day activity of GPx was significant (P ≤ 0.05) decline in the obese and diabetic group likely as a compensatory response to increased oxidative stress. Garlic supplementation significantly (P ≤ 0.05) increased GPx activity on 21st day and 28th day suggesting alleviation of oxidative burden in Figure 1f.

Conversely, the level of lipid peroxidase (LPO) was significantly (P ≤ 0.05) elevated in obese, diabetic and garlic treated group at the 7th day and 14th day. Garlic treated group led to a marked reduction in LPO level, with significant (P ≤ 0.05) decline observed compared to obese group at 21st day and at 28th day, the level of LPO in garlic treated group was significantly (P ≤ 0.05) reduced compared to obese and diabetic group approaching levels seen in controls in Figure 1g. The level of LPO in obese and diabetic groups has no significant difference throughout the study.

Discussion

Our present study assessed the protective effect of daily consumable dosage of garlic against the diabetic symptoms such as hyperglycemia, hyperphagia, polydipsia, obesity, inflammation, oxidative stress, and its role in improving the lipid profile.

Currently, diabetes is one of the important metabolic disorders due to acculturation in western dietary habits and sedentary lifestyle. In our study, we observed rats in the obese group gained weight and significantly increased body weight as compared to the control group, although there was no significant difference in their amount of food consumption, but the percentage of fat in the diet of two groups was different. Body weight and weight gain were significantly higher in diabetic group also, but the diabetic group showed slightly less weight gain probably due to insulin deficiency-induced catabolism. Diabetic group had significant increased food and water consumption as compared to control and obese groups. Garlic significantly attenuated hyperphagia and polydipsia through allicin that enhance insulin sensitivity and modulate appetite via glucose regulation pathways. Garlic treated diabetic rats showed significant reduction in body weight and weight gain, supporting evidence that garlic improves lipid metabolism, reduces adiposity, and enhances energy expenditure.[30,31,32]

Our study also demonstrated that garlic in diabetic rats led to a significant reduction in fasting and postprandial blood glucose levels compared to diabetic controls. This aligns with previous research indicating that garlic oil and its constituent, diallyl trisulfide, improved glycaemic control in streptozotocin-induced diabetic rats by enhancing insulin secretion and sensitivity.[33,34] However, studies have reported long-term treatment of diabetes with garlic oil can improve oral glucose tolerance but not through the action of diallyl disulfide (DADS), even high doses of DADS may further complicate the metabolic disturbances in diabetes.[35] These discrepancies may be attributed to variations in the specific garlic compounds used, their dosages, or differences in the experimental designs, including the duration and dosage of treatment and the animal models employed. Our findings suggest that consuming garlic may help diabetics manage their glucose homeostasis. Overall, these findings suggest that garlic consumption improves metabolic homeostasis by mitigating hyperglycemia, reducing excessive caloric and fluid intake, and enhancing energy metabolism in diabetic conditions.

A significant increase in TC, TG levels and decrease in the level of HDL was found in diabetic group while garlic treatment effectively mitigates these changes. As reported earlier, Zhang et al., 2023 reported garlic oil may lower TC and TG levels by encouraging lipoprotein metabolism and conversion, preventing cholesterol absorption, delaying hepatic cholesterol synthesis, and hastening TG breakdown.[36]

Lecithin cholesterol acyltransferase, an enzyme that promotes HDL maturation and cholesterol reverse transport, is regulated by alliin, allicin, and S-allyl cysteine (SAC), which may be the cellular mechanism behind the protective benefits.[37] MAPK and c-Jun N-terminal Kinase are the two primary signaling pathways which are involved in the anti-hyperlipidemic process activated by allicin. These mechanisms collectively suggest that garlic supplementation can be beneficial in managing lipid abnormalities associated with diabetes. However, our results contradict earlier findings.[38] These discrepancies might be due to variations in experimental conditions, including differences in garlic preparation, animal models, and severity of metabolic alterations.

The present study indicates that garlic significantly modulates oxidative stress markers in diabetic rats throughout 28 days, reflected by increased activities of antioxidant enzymes such as SOD, GST, and elevated GSH content. These enhancements suggest improved cellular redox homeostasis, likely due to allicin and SAC, which activate the Nrf2 signaling pathway, promoting transcription of antioxidant genes.[39] In addition, the marked reduction in LPO levels at the 28th day indicates decreased oxidative membrane damage, suggesting that garlic effectively suppresses ROS-mediated lipid peroxidation.[11] Thus, the results of our study highlights garlic’s potent antioxidative properties, potentially through Nrf2 activation, free radical scavenging, and modulation of redox enzyme systems, supporting its therapeutic promise in mitigating oxidative damage and metabolic complications in diabetes.

However, this study did not reveal the impact of cooking or additive effect of other regularly used spices. Further investigations could be designed to determine the efficacy of combinatorial spices with garlic in daily consumable doses.

Conclusions

The present study suggests that consumable dosage of garlic may serve as an effective natural adjunct in the management of diabetes and its associated complications. Garlic consumption effectively reduced food intake, water consumption, and body weight, suggesting an improvement in metabolic regulation. Furthermore, garlic significantly improved the lipid profile by lowering TC and TGs while elevating HDL levels. Garlic administration led to a marked reduction in hyperglycemia, demonstrating its antidiabetic efficacy; however, this effect was time dependent, with significant improvements observed during fasting, 30 min, and 120 min OGTT measurements, but not at the 60 min and 90 min time points. Although a decrease in antioxidant enzyme activity was observed, this may reflect a reduced oxidative burden rather than impaired defense, as garlic is known to modulate redox homeostasis. Overall, these findings support the role of garlic as a functional food with beneficial effects on glycemic control, lipid metabolism, and energy balance in diabetic conditions.

Ethical statement

All the experiments were carried out in accordance with the CPCSEA guidelines, and the study was approved by the Institutional Animal Ethics Committee (IAEC) [Approval letter No. Dean/2023/IAEC/6201, Date: 10.08.2023].

Conflicts of interest

There are no conflicts of interest.

Funding Statement

AS received his doctoral fellowship from the Council of Scientific and Industrial Research-Human Resource Development Group, New Delhi, Government of India: F. No. 09/013(0943)/2020-EMR-I.

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