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Lee, Hong, Yoo, Chung, and Kim: Anti-Helicobacter pylori activity and inhibition of gastritis by Allium hookeri extract


Allium hookeri is widely consumed plant as a vegetable and herbal medicine in southeastern Asia. Allium hookeri has been reported antioxidant, improvement of bone health and antidiabetic effects. In the present study, we investigated the potential inhibitory effect of Allium hookeri extract (AHE) on Helicobacter pylori. The in vitro anti-bacterial activities of AHE were determined by disk agar diffusion method. Also, the inhibition effect of the AHE on H. pylori infection was investigated using a mouse model. H. pylori colonization was confirmed by rapid urease tests, as described previously. Mucosal damage was evaluated grossly and histologically according to previously described criteria. As the results of the disk agar diffusion assay, CLR, AMX and MTZ inhibited the bacterial growth with inhibition zone of 19.2, 15.2 and 7.5 mm, respectively. AHE 100 µg/mL showed an inhibition zone value of 20.6 mm. Rapid urease tests of the mice stomachs demonstrated a significant reduction in H. pylori colonization. In addition to the therapeutic effect against H. pylori infection, the AHE reduced mucosal inflammation and epithelial damages in the stomach of H. pylori-infected mice. These results demonstrate that the AHE successfully cured an H. pylori infection and treated the H. pylori infection. This AHE could be a promising treatment for patients with gastric complaints including gastritis caused by H. pylori.

Helicobacter pylori is the most important etiological agent of chronic gastritis and peptic ulcers and also increases the risk for gastric cancer [12]. Accumulating evidence has demonstrated that eradicating H. pylori in the stomach by administering oral antimicrobial agents results in the resolution of H. pylori-associated gastroduodenal diseases [34]. In addition, eradication of H. pylori also decreases the risk for gastric carcinogenesis [5]. Triple combination therapy, using two antibacterial antibiotics and a proton pump inhibitor, achieves a high eradication rate [6]; however, such combination therapy does not always successfully eradicate H. pylori.
Antibiotic chemotherapy occasionally produces side effects and fails to eliminate the bacterial infection [7]. The occurrence of strains resistant to antibiotics is expected to increase; thus, it is important to search for nonantibiotic substances to cure these infections [8].
Allium species contain an abundance of organo-sulfur compounds, volatile sulfur compounds, proteins, prostaglandins, fructan, vitamins, and polyphenols, and particularly, its sulfur and numerous phenolic compounds make them great of interest [9]. Allium hookeri which is a member of family Alliaceae subgenus Amerallium, is found in Ceylon, Greece, Yunnan, Southern China, Bhutan, Sri Lank, and India. These plants have been used by the locals to treat cough and cold, and heal burns and wounds [10]. Several studies have demonstrated antioxidant activity and anti-inflammatory effect of Allium hookeri [111213], however, there is still insufficient information available on the anti-helicobacter effect of Allium hookeri extract.
The goal of this study was to determine the anti-Helicobacter pylori activity and inhibition of Helicobacter pylori-induced inflammation effects of the Allium hookeri root extract (AHE).

Materials and Methods

Preparation of Allium hookeri extract

The dry mass of Allium hookeri was purchased from an Oriental Pharmacy (Iksan, Korea), was according to the standard as mentioned in Korean Pharmacopoeia and Korean Herbal Pharmacopoeia, which are the official compendia of standard. The procedure for preparing AHE was as follows. The air-dried mass of Allium hookeri (100 g) was cut into pieces and extracted twice with 70% (v/v) ethanol (three times as much as the weight of the dried plants) for 3 hours at 100℃. After filtration through a 400-mesh filter cloth, the filtrate was refiltered through filter paper (Whatman, No. 5) and concentrated on a rotary evaporator (N-2110, EYELA, Tokyo, Japan) and the concentrated filtrate was evaporated to dryness under vacuum with freezing dryer (FreeZone 2.5, Labconco, Kansas, USA). Finally, the solid residue was collected, placed in sealed bottles and stored at −20℃.

Determination of anti-bacterial activity

The in vitro anti-bacterial activities of AHE were determined by disk agar diffusion method [14]. Briefly, a total volume of 100 µL of H. pylori suspension (1×108 colony forming units (CFUs)/mL) was spread onto Mueller Hinton agar plates (BBL) containing 10% sheep blood. Sterile paper disks (6 mm, BBL) were placed on the agar surface with 3 different concentrations of AHE extracts (12.5, 25 and 50 µg/mL) individually. DMSO was used as negative control and antibiotics amoxicillin (AMX, 0.05 mg/mL), clarithromycin (CLR, 0.05 mg/mL), metronidazole (MTZ, 0.8 mg/mL), and alliin (0.05 mg/mL) were used as positive control. After 72 h for incubation at 37℃ under the microaerophilic condition with humidity, the inhibition zone was determined in diameter.


5-week aged Specific pathogen-free (SPF) male C57BL/6 mice were procured from Samtako Co. (Osan, Korea). All animals were kept at the inspecting facility of Wonkwang University (Iksan, South Korea) for 1 week to allow acclimation before experimentation. Thereafter, they were kept in an isolated SPF barrier room with regulated temperature (23±1℃), humidity (50±5%) and light/dark cycle (12/12 h). The animals were fed a sterilized (2 M rad radiation) pellet diet (Purina, Seoul, Korea) and sterilized water ad libitum. All studies were performed in accordance with the Guide for Animal Experimentation of Wonkwang University and approved by the Institutional Animal Care and Use Committee of Wonkwang University. All efforts were made to minimize pain or discomfort to the animals used.

Bacterial inoculation

H. pylori SS1 (B0890, Helicobacter pylori Korean Type Culture Collection, HPKTCC) was incubated in brain-heart infusion broth containing 10% fetal bovine serum at 37℃ overnight under a micro-aerophilic atmosphere and allowed to grow to a density of ~2.0×109 CFU/mL culture broth. Animals were inoculated 3 times at 3-day intervals by intragastric inoculation of 1.0×109 CFU H. pylori suspended in 0.5 mL broth. The challenged animals were confirmed to be H. pylori-positive by the stool antigen analysis with SD Bioline H. pylori Ag kit (Standard Diagnostics, Inc, Yongin, Korea) as described previously [15].

In vivo study protocol

The inhibition effect of the AHE on H. pylori infection was investigated using a mouse model. Mice were divided into four groups: negative control (group I, n=10); H. pylori-infected, AHE-untreated animals (group II, n=10); and H. pylori-infected, AHE (25 mg/kg)-treated animals-treated animals (group III, n=10); and H. pylori-infected, AHE (50 mg/kg)-treated animals (group IV, n=10); and H. pylori-infected, AHE (100 mg/kg)-treated animals (group V, n=10). The AHE was administered orally daily at 25, 50 and 100 mg/kg/day dose during a 4 week treatment period.
At 4 weeks after H. pylori inoculation, all animals were sacrificed and their stomachs were dissected after ether euthanasia. Each stomach was opened along the greater curvature and washed with saline. Then, half of the glandular mucosa was scraped for detecting colonizing H. pylori, and the residual part was formalin-fixed and embedded in paraffin for histological observations. H. pylori colonization was confirmed by rapid urease tests, as described previously [16]. Mucosal damage was evaluated grossly and histologically according to previously described criteria [16].

Statistical analysis

Values for all parameters under study were recorded for each experimental unit, and the statistical analysis was performed using a general linear model. Values are reported as average ± standard deviation, when appropriate. Student's t-test was used for pair-wise comparisons. Incidence percentages (95% confidence intervals [CIs]) were calculated with the MiniTab statistical software program (Minitab, State College, PA, USA). A P-value <0.05 was considered significant.


Yield of Allium hookeri extract

The extract yield of the Allium hookeri extract with 70% ethanol was 12.54%. We analyzed AHE composition by LC. The retention time of alliin in the specified LC condition was 9.667 min. The concentration of alliin in AHE was 710 µg/mL

Growth inhibition of H. pylori

We conducted the investigation of relative inhibitory potency of AHE against H. pylori SS1 growth, using the disk agar diffusion assay. AHE were tested at a maximum concentration of 100 µg/mL. For referencing, inhibitory effects of standard antimicrobial agents for treatment of H. pylori infection, with CLR and AMX at 50 µg/mL, and metronidazole (MTZ) at 800 µg/mL, and alliin at 50 µg/mL, were determined as well. To quantitative the inhibitory effect of H. pylori, the diameter of growth inhibition area was measured and expressed in millimeters and presented in Table 1. As shown in Table 1, tested agents showed a wide range of inhibitory effect against H. pylori growth with inhibition zone ranging from 0 to 20.2 mm. The antibiotics CLR, AMX and MTZ inhibited the bacterial growth with inhibition zone of 19.5, 15.6 and 7.6 mm, respectively. Alliin, an active ingredient of Allium hookeri, inhibited the bacterial growth with inhibition zone of 15.6 mm. AHE 100 µg/mL showed an inhibition zone value of 20.6 mm (Table 1).

Rapid urease test

Repeated intragastric inoculation (1.0×109 CFU/mouse, 3 times) of H. pylori to C57BL/6 mice revealed positive reaction (red color) in Campylobacter-like organism test (CLO) test on the gastric mucosa (Figure 1). The stomachs of H. pylori-infected mice orally treated with AHEs 25, 50 and 100 mg/kg/day dose during a 4 week treatment period displayed positive reaction in 70, 50, and 10%, respectively (Table 2). Also, we calculated CLO scores as described previously [16]. As shown in Figure 2, AHEs exhibited a significant decrease of CLO scores as compared to H. pylori infected group. These mean that AHE could eliminate significantly the cases of H. pylori colonization.

Histopathological analysis

Pathological changes in the gastric mucosa were negligible in animals from non-H. pylori inoculated group I. In contrast, gastric atrophy and ulceration developed in the gastric mucosa of mice in group II (H. pylori inoculation only), indicating marked mucosal destruction. However, mice in group III, IV and V (H. pylori + AHEs 25, 50 and 100 mg/kg/day individually) revealed markedly improved the villi lesions. The histopathological lesion score in AHEs treated animals significantly lower than that in the infection control group II (H. pylori inoculation only) (Table 3).


H. pylori highly colonize the human gastric mucosa and perfectly adapted to that environment. Concerning pathology, H. pylori causes gastritis and is classified as a major primary risk factor for the development of gastric or peptic ulcers, gastric adenocarcinoma and mucosa-associated lymphoid tissue lymphoma [17].
In the present study, we identified inhibition activity of the AHE against H. pylori in a mouse model. Rapid urease tests of the mice stomachs demonstrated a significant reduction in H. pylori colonization. In addition to the therapeutic effect against H. pylori infection, the AHE reduced mucosal inflammation and epithelial damages in the stomach of H. pylori-infected mice. It is likely that H. pylori eradication caused a decrease in the degree of inflammation in the stomach, although there is a possibility that AHE itself has an anti-inflammatory effect on gastric mucosa.
Allium hookeri is a wild herb cultivated in India, Myanmar, Nepal, and China. It is mainly used as food supplement and medicinal food. The beneficial effects of Allium hookeri has been extensively investigated including, anti-oxidant [18], anti-inflammatory [11], anti-microbial [19], anti-obesity [20] and antidiabetic [21]. Its beneficial effect is attributed to the sulfur compounds, phenolic compounds, phytosterols and vitamin C [22]. Allicin and ten alkyl thiosulfinates from Allium hookeri root extract were characterized by HPLC-ESIMS [23]. Non-volatile organosulfur compounds, methiin and cycloalliin were detected as major compounds and volatile compounds such as allyl methyl sulphides and dimethyl sulphides were identified from Allium hookeri [24]. Some of chemicals in Allium hookeri have showed biological activities. Ferulic acid-4-O-β-D-glucopyranoside isolated from Allium hookeri root has antioxidant activity [25]. The hot-water extract of Allium hookeri containing alliin, sinapic acid, and ferulic acid exhibited beneficial effects on bone health [26].
Although triple therapy, using two antibacterial antibiotics and a proton pump inhibitor, is effective and its short duration helps maintain patient compliance, a considerable number of patients experience undesirable side effects, such as diarrhea, epigastric pain, nausea, and bloating [27]. In contrast, Allium hookeri is relatively safe and contains a wide range of thiosulphinates such as allicin which are thought to be responsible for the antibacterial activity [212223]. These safety characteristics of AHE may therefore be appropriate for use in prevention and therapy against H. pylori infection.
In this study, AHE showed a significant inhibition effect against H. pylori infection. It could be a promising AHE treatment for patients with gastric complaints including gastric ulcers caused by H. pylori. AHE may be useful to treat patients with an H. pylori infection with high therapeutic efficacy and safety.


This paper was supported by Wonkwang University in 2018.


Conflict of interests: The authors declare that there is no financial conflict of interests to publish these results.


1. Maruta F, Ota H, Genta RM, Sugiyama A, Tatematsu M, Katsuyama T, Kawasaki S. Role of N-Methyl-N-nitrosourea in the induction of intestinal metaplasia and gastric adenocarcinoma in Mongolian gerbils infected with Helicobacter pylori. Scand J Gastroenterol. 2001; 36(3):283–290. PMID: 11305516.
2. Sugiyama A, Maruta F, Ikeno T, Ishida K, Kawasaki S, Katsuyama T, Shimizu N, Tatematsu M. Helicobacter pylori infection enhances N-methyl-N-nitrosourea-induced stomach carcinogenesis in the Mongolian gerbil. Cancer Res. 1998; 58(10):2067–2069. PMID: 9605743.
3. Asaka M, Sugiyama T, Kato M, Satoh K, Kuwayama H, Fukuda Y, Fujioka T, Takemoto T, Kimura K, Shimoyama T, Shimizu K, Kobayashi S. A multicenter, double-blind study on triple therapy with lansoprazole, amoxicillin and clarithromycin for eradication of Helicobacter pylori in Japanese peptic ulcer patients. Helicobacter. 2001; 6(3):254–261. PMID: 11683930.
4. Salih BA, Abasiyanik MF, Saribasak H, Huten O, Sander E. A follow-up study on the effect of Helicobacter pylori eradication on the severity of gastric histology. Dig Dis Sci. 2005; 50(8):1517–1522. PMID: 16110845.
5. Maruta F, Sugiyama A, Ishizone S, Miyagawa S, Ota H, Katsuyama T. Eradication of Helicobacter pylori decreases mucosal alterations linked to gastric carcinogenesis in Mongolian gerbils. J Gastroenterol. 2005; 40(1):104–105. PMID: 15692797.
6. Misiewicz JJ, Harris AW, Bardhan KD, Levi S, O'Morain C, Cooper BT, Kerr GD, Dixon MF, Langworthy H, Piper D. One week triple therapy for Helicobacter pylori: a multicentre comparative study. Gut. 1997; 41(6):735–739. PMID: 9462204.
7. Buenz EJ, Bauer BA, Schnepple DJ, Wahner-Roedler DL, Vandell AG, Howe CL. A randomized Phase I study of Atuna racemosa: a potential new anti-MRSA natural product extract. J Ethnopharmacol. 2007; 114(3):371–376. PMID: 17889468.
8. Liu CS, Cham TM, Yang CH, Chang HW, Chen CH, Chuang LY. Antibacterial properties of Chinese herbal medicines against nosocomial antibiotic resistant strains of Pseudomonas aeruginosa in Taiwan. Am J Chin Med. 2007; 35(6):1047–1060. PMID: 18186590.
9. Dziri S, Hassen I, Fatnassi S, Mrabet Y, Casabianca H, Hanchi B, Hosni K. Phenolic constituents, antioxidant and antimicrobial activities of rosy garlic (Allium roseum var. odoratissimum). J Funct Foods. 2012; 4(2):423–432.
10. Sharma G, Gohil RN, Kaul V. Cytological status of Allium hookeri Thwaites (2n=22). Genet Resour Crop Evol. 2011; 58(7):1041–1050.
11. Bae GC, Bae DY. The anti-inflammatory effects of ethanol extract of Allium hookeri cultivated in South Korea. Korean J Herbol. 2012; 27(6):55–61.
12. Kim CH, Lee MA, Kim TW, Jang JY, Kim HJ. Anti-inflammatory effect of Allium hookeri root methanol extract in LPS-induced RAW264.7 cells. J Korean Soc Food Sci Nutr. 2012; 41(11):1645–1648.
13. Won JY, Yoo YC, Kang EJ, Yang H, Kim GH, Seong BJ, Kim SI, Han SH, Lee SS, Lee KS. Chemical components, DPPH radical scavenging activity and inhibitory effects on nitric oxide production in Allium hookeri cultivated under open field and greenhouse conditions. J Korean Soc Food Sci Nutr. 2013; 42(9):1351–1356.
14. Castillo-Juárez I, Rivero-Cruz F, Celis H, Romero I. Anti-Helicobacter pylori activity of anacardic acids from Amphipterygium adstringens. J Ethnopharmacol. 2007; 114(1):72–77. PMID: 17768020.
15. Moon DI, Shin EH, Oh HG, Oh JS, Hong S, Chung Y, Kim O. Usefulness of a Helicobacter pylori stool antigen test for diagnosing H. pylori infected C57BL/6 mice. Lab Anim Res. 2013; 29(1):27–32. PMID: 23573105.
16. Lee HA, Hong S, Oh HG, Park SH, Kim YC, Park H, Jeong GS, Kim O. In vitro and in vivo Antibacterial Activities of Cinnamomum cassia Extracts against Helicobacter pylori. Lab Anim Res. 2010; 26(1):21–29.
17. Wroblewski LE, Peek RM Jr, Wilson KT. Helicobacter pylori and gastric cancer: factors that modulate disease risk. Clin Microbiol Rev. 2010; 23(4):713–739. PMID: 20930071.
18. Lee EB, Kim JH, Yang JH, Kim YS, Jun HI, Ki B, Yi SH, Kim YS, Han SC, Kim DG. Antioxidant and longevity properties of the root of Allium hookeri in Caenorhabditis elegans. Kor J Pharmacogn. 2015; 46(3):234–242.
19. Li R, Wang YF, Sun Q, Hu HB. Chemical composition and antimicrobial activity of the essential oil from Allium hookeri consumed in Xishuangbanna, southwest China. Nat Prod Commun. 2014; 9(6):863–864. PMID: 25115101.
20. Yang HS, Choi YJ, Jin HY, Lee SC, Huh CK. Effects of Allium hookeri root water extracts on inhibition of adipogenesis and GLUT-4 expression in 3T3-L1 adipocytes. Food Sci Biotechnol. 2016; 25(2):615–621.
21. Roh SS, Kwon OJ, Yang JH, Kim YS, Lee SH, Jin JS, Jeon YD, Yokozawa T, Kim HJ. Allium hookeri root protects oxidative stress-induced inflammatory responses and β-cell damage in pancreas of streptozotocin-induced diabetic rats. BMC Complement Altern Med. 2016; 16:63–72. PMID: 26888412.
22. Ayam VS. Allium hookeri, Thw. Enum. A lesser known terrestrial perennial herb used as food and its ethnobotanical relevance in Manipur. Afric J Food Agric Nutr Dev. 2011; 11(6):5389–5412.
23. Rhyu DY, Park SH. Characterization of Alkyl thiosulfinate in Allium hookeri root using HPLC-ESI-MS. J Korean Soc Appl Biol Chem. 2013; 56(4):457–459.
24. Kim S, Kim DB, Lee S, Park J, Shin D, Yoo M. Profiling of organosulphur compounds using HPLC-PDA and GC/MS system and antioxidant activities in hooker chive (Allium hookeri). Nat Prod Res. 2016; 30(24):2798–2804.
25. Jun HI, Jang H, Ahn D, Kim DK, Yang JH, Yun BS, Kim YS. Isolation and characterization of phenolic compound from Allium hookeri root for potential use as antioxidant in foods. Food Sci Biotechnol. 2015; 24(6):2031–2034.
26. Park H, Jeong J, Hyun H, Kim J, Kim H, Oh HI, Choi JY, Hwang HS, Oh DB, Kim JI, Kim HH. Effects of a hot-water extract of Allium hookeri roots on bone formation in human osteoblast-like MG-63 cells in vitro and in rats in vivo. Planta Med. 2016; 82(16):1410–1415. PMID: 27280935.
27. Sakamoto I, Igarashi M, Kimura K, Takagi A, Miwa T, Koga Y. Suppressive effect of Lactobacillus gasseri OLL2716 (LG21) on Helicobacter pylori infection in humans. J Antimicrob Chemother. 2001; 47(5):709–710. PMID: 11328791.
Figure 1

Gross findings of rapid urease test with CLO test kit. (A) Negative reaction (yellow color change) with control mice. (B) Positive reaction (red color change) with H. pylori infected mice.

Figure 2

Score of rapid urease test with CLO test kit in H. pylori infected mice was significantly decreased by Allium hookeri extracts (AHE) (*P<0.05, **P<0.01).

Table 1

Anti-H. pylori activities of Allium hookeri extract (AHE) using the disk agar diffusion method

Treatment (µg/mL) Clear zone (mm)
Clarithromycin (50) 19.5±0.70*
Amoxicillin (50) 15.6±0.60*
Metronidazole (800) 7.6±0.45
Alliin (50) 15.6±0.61*
(0) 0±0
(12.5) 5.6±0.61
AHE (25) 10.9±0.46*
(50) 16.6±0.51*
(100) 20.2±0.57*

*Significantly different with Metronidazole (P<0.05).

Table 2

Reactivity in CLO test on the gastric mucosa of mice infected with H. pylori followed by treatment with or without Allium hookeri extract (AHE)

Group Treatment n Positive %a Therapeutic %
I No treatment 10 0% (CIb0–27.6) -
II H. pylori 10 100% (CI 72.2–100) 0% (CI 0–27.6)
III H. pylori+AHE 25 mg/kg 10 70% (CI 39.7–89.2) 30% (CI 10.8–60.3)
IV H. pylori+AHE 50 mg/kg 10 50% (CI 23.7–76.3) 50% (CI 23.7–76.3)
V H. pylori+AHE 100 mg/kg 10 10% (CI 1.8–40.4)* 90% (CI 60.0–98.2)*

aThe positive percent revealed H. pylori colonization, which was observed as red color change from yellow color medium.

bIncidence percentage (95% confidential interval) was calculated with MiniTab statistic software program.

*Significantly different with H. pylori-infected Group II (P<0.05).

Table 3

Histopathological lesions scores of mice infected with H. pylori followed by treatment with or without Allium hookeri extract (AHE)

Group Treatment n Histopathological lesions score
I No treatment 10 0±0
II H. pylori 10 6.4±1.07*
III H. pylori+AHE 25 mg/kg 10 3.5±1.18*
IV H. pylori+AHE 50 mg/kg 10 2.3±1.34*
V H. pylori+AHE 100 mg/kg 10 0.8±0.79**

*Significantly different from the H. pylori-infected group II (*P<0.05, **P<0.01)

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