In vitro antimicrobial susceptibility of Actinobacillus actinomycetemcomitans

The agar dilution technique was used for determination of the antibiotic susceptibilities of 57 oral isolates and 2 nonoral isolates of Actinobacillus actinomycetemcomitans. Tetracycline, minocycline, and chloramphenicol inhibited more than 96% of the strains tested at a concentration of less than or equal to 2 micrograms/ml; 89% of the strains were inhibited by 2 micrograms of carbenicillin per ml. The other antimicrobial agents tested were less active. Approximately 10% of the A. actinomycetemcomitans strains were resistant to ampicillin, erythromycin, and penicillin G at concentrations of 32 to 64 micrograms/ml. These data suggest that tetracycline and minocycline may be valuable drugs in the treatment of A. actinomycetemcomitans infections.     

Antibacterial effect of garlic and omeprazole on Helicobacter pylori.

The antibacterial effect of a home-made raw garlic extract and commercial garlic tablets alone and in combination with antibiotics or omeprazole was determined against clinical isolates of Helicobacter pylori. MIC values of raw garlic extract and three types of commercial garlic tablets ranged from 10,000 to 17,500 mg/L. When MIC values of the commercial tablets were based on the allicin content, no differences between the three types were observed. The combination of garlic and omeprazole, studied with killing curves, showed a synergic effect which was concentration dependent. Further clinical evaluation of garlic in combination with the conventional agents for H. pylori treatment seems warranted.     

Efficacy of allicin, the reactive molecule of garlic, in inhibiting Aspergillus spp. in vitro, and in a murine model of disseminated aspergillosis

OBJECTIVES: The evaluation of allicin, the biologically active compound responsible for the antimicrobial activities of freshly crushed garlic cloves, in inhibiting Aspergillus spp. in vitro and in a murine model of disseminated aspergillosis. METHODS: Pure allicin was prepared by reacting synthetic alliin with a stabilized preparation of the garlic enzyme alliinase. We tested the in vitro efficacy of pure allicin against 31 clinical isolates of Aspergillus spp. using a microdilution broth method and following the NCCLS guidelines (document M-38P). Subsequently, the in vivo efficacy of allicin was tested in immunocompetent mice infected intravenously (iv) with Aspergillus fumigatus conidia. Allicin (5 mg/kg body weight) was administered iv once daily for 5 days post-infection or orally (po) (9 mg/kg body weight) for 5 days pre-infection and 10 days post-infection. No ill effects were observed in allicin-treated uninfected mice. RESULTS: The in vitro MICs and MFCs of allicin were between 8 and 32 mg/L, indicating that allicin in its pure form may be an effective fungicide in vitro. Time-kill studies indicate that allicin exerts its fungicidal activity within 2-12 h of administration in vitro. Allicin treatment significantly prolonged survival of infected mice (P < 0.01) from mean survival time (MST) = 7.7 days in untreated mice to MST = 21.3 and 13.9 days for allicin iv and po treated mice, respectively. Allicin iv treatment led to a significant (P < 0.001) 10-fold reduction in fungal burden in A. fumigatus infected mice as evaluated by quantitative fungal cultures of kidney tissue samples. CONCLUSIONS: These favourable results, despite the short half-life of this compound in vivo, support further studies of controlled sustained release or more prolonged administration of allicin as a treatment for aspergillosis.     

Health effects of garlic

Garlic has long been used medicinally, most recently for its cardiovascular, antineoplastic, and antimicrobial properties. Sulfur compounds, including allicin, appear to be the active components in the root bulb of the garlic plant. Studies show significant but modest lipid-lowering effects and antiplatelet activity. Significant blood pressure reduction is not consistently noted. There is some evidence for antineoplastic activity and insufficient evidence for clinical antimicrobial activity. Side effects generally are mild and uncommon. Garlic appears to have no effect on drug metabolism, but patients taking anticoagulants should be cautious. It seems prudent to stop taking high dosages of garlic seven to 10 days before surgery because garlic can prolong bleeding time.     

Inhibition of tumor growth by a novel approach: in situ allicin generation using targeted alliinase delivery

Allicin (diallyl thiosulfinate), a highly active component in extracts of freshly crushed garlic, is the interaction product of non-protein amino acid alliin (S-allyl-L-cysteine sulfoxide) with the enzyme alliinase (alliin lyase; EC 4.4.1.4). Allicin was shown to be toxic in various mammalian cells in a dose-dependent manner in vitro. We made use of this cytotoxicity to develop a novel approach to cancer treatment, based on site-directed generation of allicin. Alliinase from garlic was chemically conjugated to a mAb directed against a specific tumor marker, ErbB2. After the mAb-alliinase conjugate was bound to target tumor cells, the substrate, alliin, was added. In the presence of alliin, tumor-localized alliinase produced allicin, which effectively killed N87 and CB2, both ErbB2-expressing cells in vitro, whereas 32D cells (a murine hematopoietic progenitor cell line, devoid of the ErbB2 receptors) were not affected. Moreover, using N87, a human tumor cell line xenograft in athymic nude mice, we demonstrated for the first time, a high antitumor activity of allicin that was produced in situ by the conjugate, on alliin administration in vivo, while at the same time other tissues were unharmed due to the inert nature of alliin and the high clearance rate of allicin. The effect of the treatment on tumor growth arrest became significant 2 weeks after its onset, and it continued to rise, reaching highly significant inhibition a week later. Ten days after the end of the treatment (day 18), tumor growth inhibition was still the same.     

In vitro mechanism of inhibition of bacterial cell growth by allicin.

Diallyl thiosulfinate (allicin) is the agent found in garlic which is responsible for the antibacterial and antifungal activity of extracts of this plant. The effect of bacteriostatic concentrations of allicin (0.2 to 0.5 mM) on the growth of Salmonella typhimurium revealed a pattern of inhibition characterized by: (i) a lag of approximately 15 min between addition of allicin and onset of inhibition, (ii) a transitory inhibition phase whose duration was proportional to allicin concentration and inversely proportional to culture density, (iii) a resumed growth phase which showed a lower rate of growth than in uninhibited controls, and (iv) an entry into stationary phase at a lower culture density. Whereas DNA and protein syntheses showed a delayed and partial inhibition by allicin, inhibition of RNA synthesis was immediate and total, suggesting that this is the primary target of allicin action.     

Differential effects of alliin and allicin on apoptosis and senescence in luminal A and triple-negative breast cancer: Caspase, ΔΨm,and pro-apoptotic gene involvement

Breast cancer is the most frequent cancer in women worldwide, and drug resistance is common in all breast cancer types. The combination of natural products with chemotherapies has attracted attention, as it was found that natural compounds enhance the effects of standard cancer chemotherapeutic drugs and protect from side effects. Into the different natural products, garlic has been recognized for its antitumor properties. It is suggested that its anticancer effects are associated with its organo-sulfur compounds, especially alliin and allicin. Here, we evaluated the effects of both molecules on cell death, senescence, and their senolytic potential in luminal A and triple-negative breast cancer cells. MCF-7 (luminal A) and HCC-70 (triple-negative) cells were cultured and treated with different concentrations of alliin or allicin. Then, cell viability was determined using the WST-1 reagent. Apoptosis and caspase activity were evaluated by flow cytometry; ΔΨm was assessed using a JC-10 fluorometric assay kit. Apoptosis-related genes were evaluated by RT-PCR. Proliferation was measured using bromodeoxyuridine incorporation. We also evaluated clonogenicity, senescence (β-Galactosidase Staining), and the senolytic effect of the compounds. Our results showed that allicin has antiproliferative, anticlonogenic, and senolytic effects. In addition, allicin decreased cell viability and induced apoptosis by loss of ΔΨm, caspase-3, caspase-8, and caspase-9 activation, upregulation of NOXA, P21, and BAK, as well as downregulation of BCL-XL expression. Contrary to allicin, alliin promoted clonogenicity, induced senescence, and did not exhibit pro-apoptotic effects in breast cancer cells.     

Apoptotic killing of B-chronic lymphocytic leukemia tumor cells by allicin generated in situ using a rituximab-alliinase conjugate

Allicin, a highly active component from freshly crushed garlic, is produced upon the reaction of the small molecular weight molecule alliin, with the enzyme alliinase (EC 4.4.1.4). Because allicin was shown to be toxic to various mammalian cells in vitro, we devised a novel approach for the therapy of B-cell malignancies based on site-directed generation of allicin. Alliinase was conjugated to the monoclonal antibody rituximab, which recognizes the CD20 antigen, and the resulting conjugate was targeted to CD20+ B chronic lymphocytic leukemia (B-CLL) and other B-cell lymphomas. Upon addition of alliin, allicin was formed in situ, killing the CD20+ tumor B cells via apoptosis. Following a 72-hour treatment, an 85% and 96% reduction was observed in the number of viable B-CLL and EBV-transformed B cells, respectively. Using the human/mouse radiation chimera for the evaluation of allicin targeting in a preclinical animal model, we showed a significant reduction in the number of recovered B-CLL, mantle cell lymphoma, or EBV-transformed B cells. We conclude that our system offers a new powerful and less toxic therapy for B-CLL and other B-cell malignancies. Furthermore, combining alliinase with the appropriate monoclonal antibody may extend the application of this approach to other conditions in which the elimination of a specific cell population is desired.     

Susceptibilities of periodontopathogenic and cariogenic bacteria to antibacterial peptides, {beta}-defensins and LL37, produced by human epithelial cells

OBJECTIVES: Antimicrobial peptides are one of the factors involved in innate immunity. The susceptibility of periodontopathogenic and cariogenic bacteria to the major antimicrobial peptides produced by epithelia was investigated. METHODS: Synthetic antimicrobial peptides of human beta-defensin-1 (hBD1), hBD2, hBD3 and LL37 (CAP18) were evaluated for their antimicrobial activity against oral bacteria. They included Actinobacillus actinomycetemcomitans (20 strains), Porphyromonas gingivalis (6), Prevotella intermedia (7), Fusobacterium nucleatum (7), Streptococcus mutans (5), Streptococcus sobrinus (5), Streptococcus salivarius (5), Streptococcus sanguis (4), Streptococcus mitis (2) and Lactobacillus casei (1). RESULTS: Although the four peptides had bactericidal activity against all bacteria tested, the degree of antibacterial activity was variable against the different strains and species. The antibacterial activity of hBD1 was lower than that of the other peptides. Among the bacteria tested in this study, F. nucleatum was highly susceptible to hBD3 and LL37, and S. mutans was highly susceptible to hBD3. We measured the Zeta-potential, representing the net charge of whole bacteria, to study the relationship between susceptibility to cationic peptide and the net charge of the bacteria. Although we found some correlation in A. actinomycetemcomitans strains, we did not find a definite correlation with all the bacterial species. CONCLUSIONS: These results indicate that beta-defensins and LL37 have versatile antibacterial activity against oral bacteria.     

大蒜素联合美罗培南对耐碳青霉烯类抗生素的鲍曼不动杆菌的体外杀菌研究

目的 探讨体外大蒜素与美罗培南联合对耐碳青霉烯类抗生素的鲍曼不动杆菌的杀菌作用.方法 (1)采用EDTA-Na2纸片复合法和改良三维实验对6株多耐药鲍曼不动杆菌产生β-内酰胺金属酶进行鉴定.(2)采用M-H肉汤法,确定大蒜素、美罗培南、大蒜素+美罗培南的MIC值,计算两药联用的FIC指数,K-B纸片法鉴定大蒜素对美罗培南抑菌作用的影响,微孔板生物检测法检测大蒜素、美罗培南及两药联用的抑菌率.(3)M-H肉汤法检测还原型谷胱甘肽对大蒜素抑菌作用的影响;检测不同浓度大蒜素作用后,细菌谷胱甘肽、抗超氧阴离子自由基和总巯基的变化.(4)改良三维实验和M-H肉汤法检测大蒜素对β-内酰胺金属酶分解碳青霉烯类抗生素作用的影响.结果 (1)经EDTA-Na2纸片复合法和改良三维实验对6株多耐药鲍曼不动杆菌产生β-内酰胺金属酶进行鉴定,均产生β-内酰胺金属酶.(2)大蒜素对6株耐碳青霉烯抗生素鲍曼不动杆菌的MIC值均为512 μg/ml,美罗培南为128 μg/ml.两种药物联用FIC值为0.25,大蒜素+美罗培南较两种药物单独使用,抑菌率明显提高.(3)0.3 mg/ml还原型谷胱甘肽与不同浓度大蒜素联用后,抑菌率显著下降.大蒜素作用组较无大蒜素作用组及高浓度大蒜素作用组较低浓度大蒜素作用组细菌谷胱甘肽、抗超氧阴离子自由基、总巯基水平显著下降.(4)美罗培南+大蒜素+酶提取物组抑菌率较美罗培南+酶提取物组显著提高.结论 大蒜素对耐碳青霉烯类抗生素的鲍曼不动杆菌抑制作用与其引起细菌体内氧化失衡有关;大蒜素与美罗培南联用对该细菌有协同作用,机制可能与大蒜素抑制β-内酰胺金属酶对美罗培南的分解作用有关.     

Polyvinylpyrrolidone/cellulose acetate electrospun composite nanofibres loaded by glycerine and garlic extract with in vitro antibacterial activity and release behaviour test

The antibacterial activity of garlic (Allium sativum) is believed to be due to its organosulfur compounds, which can supposedly be used further in biomedical applications. This paper reported the use of electrospinning to encapsulate a garlic extract and glycerine in nanofibrous mats. Polyvinylpyrrolidone (PVP) and cellulose acetate (CA) were the building blocks of the composite fibres that served as the hydrophilic matrix to encapsulate the garlic extract with glycerine added mainly to improve the mechanical characteristics of the composite fibres. The combinations of the fibres were PVP/CA, PVP/CA/garlic, PVP/CA/glycerine, and PVP/CA/glycerine/garlic. The characterizations included the morphology, chemical interaction, swelling degree, weight loss, acidity level, wettability, in vitro antibacterial test, and release behaviour test. The composite nanofibrous mats were uniform, bead-free with a size ranging from 350 nm to 900 nm. The Fourier-transform infrared spectra proved the presence of the garlic extract and glycerine in the fibres. The swelling degree test showed that the fibrous mats generally did have maximum swelling degrees above 100% except for the PVP/CA fibrous mat, whose maximum value was not achieved within 48 hours. The fibrous mat with glycerine showed generally larger weight loss compared to the fibrous mats without glycerine. The result of the contact angle measurement proved that the composite fibres are all hydrophilic with the PVP/CA/glycerine/garlic fibres being the least hydrophilic. The pH level of the fibre mats was from 3.7 to 4.0 due to the use of acetic acid. The Young''s modulus and ultimate tensile strength of the mats were significantly reduced due to the presence of glycerine. The encapsulation of the garlic extract in the fibres did not eliminate the antibacterial activity of the garlic extract, as proven in the in vitro antibacterial test. The release of the garlic extract from the composite PVP/CA/glycerine/garlic fibres was found to be the largest due to the large diameter of the fibres, while the blend of PVP with CA successfully reduced the rate of release due to the insolubility of CA. We successfully encapsulated the garlic extract and glycerine in the PVP/CA nanofibrous mats with antibacterial activity.

The in-depth analysis of the characteristics of garlic-loaded nanofibers mats.     

Antifungal activity in human urine and serum after ingestion of garlic (Allium sativum).

A fresh extract of garlic (Allium sativum) was administered orally to human volunteers. At intervals, serum and urine were collected and assayed for antifungal activity. The maximum tolerable dose was determined to be 25 ml of garlic extract. Larger amounts caused severe burning sensations in the esophagus and the stomach and vomiting. After oral ingestion of 25 ml of the extract, anticandidal and anticryptococcal activities were detected in undiluted serum 0.5 and 1 h after ingestion. No detectable antifungal activity was found in the excreted urine at any time after oral ingestion. Oral garlic is of limited value in the therapy of human fungal infections.     

Herbal medicines for treatment of bacterial infections: a review of controlled clinical trials

OBJECTIVES: Many hundreds of plant extracts have been tested for in vitro antibacterial activity. This review is a critical evaluation of controlled clinical trials of herbal medicines with antibacterial activity. METHODS: Four electronic databases were searched for controlled clinical trials of antibacterial herbal medicines. Data were extracted and validated in a standardized fashion, according to predefined criteria, by two independent reviewers. RESULTS: Seven clinical trials met our inclusion criteria. Four of these studies were randomized. Three trials of garlic and cinnamon treatments for Helicobacter pylori infections reported no significant effect. Bacterial infections of skin were treated in four trials. Positive results were reported for an ointment containing tea leaf extract in impetigo contagiosa infections. Two trials of tea tree oil preparations used for acne and methicillin-resistant Staphylococcus aureus, and one trial of Ocimum gratissimum oil for acne, reported results equivalent to conventional treatments. CONCLUSIONS: Few controlled clinical trials have been published and most are methodologically weak. The clinical efficacy of none of the herbal medicines has so far been demonstrated beyond doubt. This area seems to merit further study through rigorous clinical trials.     

Antimalarial activity of allicin, a biologically active compound from garlic cloves

The incidence of malaria is increasing, and there is an urgent need to identify new drug targets for both prophylaxis and chemotherapy. Potential new drug targets include Plasmodium proteases that play critical roles in the parasite life cycle. We have previously shown that the major surface protein of Plasmodium sporozoites, the circumsporozoite protein (CSP), is proteolytically processed by a parasite-derived cysteine protease, and this processing event is temporally associated with sporozoite invasion of host cells. E-64, a cysteine protease inhibitor, inhibits CSP processing and prevents invasion of host cells in vitro and in vivo. Here we tested allicin, a cysteine protease inhibitor found in garlic extracts, for its ability to inhibit malaria infection. At low concentrations, allicin was not toxic to either sporozoites or mammalian cells. At these concentrations, allicin inhibited CSP processing and prevented sporozoite invasion of host cells in vitro. In vivo, mice injected with allicin had decreased Plasmodium infections compared to controls. When sporozoites were treated with allicin before injection into mice, malaria infection was completely prevented. We also tested allicin on erythrocytic stages and found that a 4-day regimen of allicin administered either orally or intravenously significantly decreased parasitemias and increased the survival of infected mice by 10 days. Together, these experiments demonstrate that the same cysteine protease inhibitor can target two different life cycle stages in the vertebrate host.     

Feasibility study of a surface-coated lung model to quantify active agent deposition for preclinical studies

BackgroundMultiple drug resistance of a growing number of bacterial pathogens represents an increasing challenge in conventional curative treatments of infectious diseases. However, the development and testing of new antibiotics is associated with a high number of animal experiments.MethodsA symmetrical parametrized lung test rig allowing the exposure of air-passage surfaces to antibiotics was designed and tested to demonstrate proof-of-principle with aerosols containing allicin, which is an antimicrobial natural product from garlic. An artificial lung surface is coated with bacteria embedded in a hydrogel and growth inhibition is visualized by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, that is reduced from colourless to the dark blue formazan in the presence of metabolically active, living cells. A nebulizer is used to generate the aerosols.FindingsThe results show that allicin has an antibiotic effect as an aerosol and that the deposition pattern of the active agent occurred mainly around the carinal regions.InterpretationThe model represents an integral system for continuous, spatial detection of aerosol deposition and allows the analysis of bacterial behaviour and the toxicity of the active agent. Thus, the deposition of antimicrobial aerosols on the bronchial surfaces is characterized in preliminary tests without any animal experiments.     

Susceptibilities of oral bacteria and yeast to mammalian cathelicidins

The effects of cathelicidins against oral bacteria and clinically important oral yeasts are not known. We tested the susceptibilities of Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum, Porphyromonas gingivalis, Streptococcus sanguis, Candida krusei, Candida tropicalis and Candida albicans to the following cathelicidins: FALL39, SMAP29, and CAP18. SMAP29 and CAP18 were antimicrobial, whereas FALL39 did not exhibit antimicrobial activity. Future studies are needed to determine the potential use of these antimicrobial peptides in prevention and treatment of oral infections.     

Antibacterial activity of human neutrophil defensins in experimental infections in mice is accompanied by increased leukocyte accumulation.

Neutrophil defensins (or human neutrophil peptides-HNP) are major constituents of the azurophilic granules of human neutrophils and have been shown to display broad-spectrum antimicrobial activity. Other activities of these defensins, which are released from stimulated neutrophils, include cytotoxic, stimulatory, and chemotactic activities toward a variety of target cells. We studied the potential use of HNP-1 for antibacterial therapy of experimental bacterial infections in mice. In experimental peritoneal Klebsiella pneumoniae infections in mice, HNP-1 injection was shown to markedly reduce bacterial numbers in the infected peritoneal cavity 24 h after infection. This antibacterial effect was found to be associated with an increased influx of macrophages, granulocytes, and lymphocytes into the peritoneal cavity. These leukocytes appeared to be a requirement for the antibacterial effect, since in leukocytopenic mice administration of HNP-1 did not display antibacterial activity. HNP-1 treatment also reduced bacterial numbers in experimental K. pneumoniae or Staphylococcus aureus thigh muscle infections. In this model, radiolabeled HNP-1 was found to accumulate at the site of infection, whereas most of the injected HNP-1 was rapidly removed from the circulation via renal excretion. These results demonstrate that neutrophil defensins display marked in vivo antibacterial activity in experimental infections in mice and that this activity appears to be mediated, at least in part, by local leukocyte accumulation.     

Garlic extract and two diallyl sulphides inhibit methicillin-resistant Staphylococcus aureus infection in BALB/cA mice

OBJECTIVES: The inhibitory effect of garlic extract, diallyl sulphide and diallyl disulphide against methicillin-resistant Staphylococcus aureus (MRSA) infection in BALB/cA mice was studied. The influence of these agents upon the levels of fibronectin, interleukin-6 and lipid oxidation in MRSA-infected mice was examined. METHODS: Garlic extract at 100% and 50%; diallyl sulphide (DAS) at 10% and 5%; diallyl disulphide (DADS) at 1% and 0.5% were used in this study. Sixteen clinical MRSA isolates obtained from infected patients were used in this study (n=16). Mice were infected by injecting 200 microL MRSA-PBS solution, which contained 10(7) cfu, via the tail vein. At 16 h post-infection (p.i.), garlic extract, DAS or DADS at 200 microL was administrated orally. At 24 h p.i., mice were killed and blood, liver, kidney and spleen of each mouse were collected. Plasma and the filtrate from each organ and serial dilutions were used to determine colony count. Plasma fibronectin level was determined by rabbit anti-rat fibronectin antibody and quantified by ELISA. Interleukin-6 levels were determined by commercial kit. Lipid oxidation was determined by measuring malondialdehyde levels. RESULTS: The oral administration of these agents significantly decreased the viability of MRSA, in plasma, liver, kidney and spleen (P<0.05). MRSA infection significantly increased fibronectin and interleukin-6 levels in plasma of MRSA-infected mice (P<0.05); however, the oral administration of garlic extract and two diallyl sulphides significantly reduced both fibronectin and interleukin-6 levels (P<0.05). MRSA infection also significantly enhanced lipid oxidation in plasma and three organs (P<0.05). The treatments of garlic extract and two diallyl sulphides significantly decreased the malondialdehyde level and showed antioxidant protection (P<0.05). CONCLUSIONS: These data strongly supported the conclusion that garlic extract, diallyl sulphide and diallyl disulphide possessed multiple protective functions against MRSA infection, in which diallyl sulphide and diallyl disulphide could be considered as novel therapeutic agents for the treatment of MRSA infection.     

大蒜素对LM-8细胞Bcl-2及Bax表达的影响

背景:有研究证实,大蒜素对LM-8细胞增殖及凋亡有影响.目的:观察大蒜素干预C3H小鼠骨肉瘤细胞株LM-8细胞Bcl-2、Bax凋亡蛋白的表达,以及LM-8细胞的形态学变化与Bcl-2及Bax变化的关系.设计:随机分组,非盲法,细胞水平体外实验.单位:实验于2006-09/2007-05在华中科技大学同济医学院附属协和医院中心实验室完成.材料:实验所用C3H小鼠LM-8骨肉瘤细胞株购自解放军第四军医大学实验动物中心.大蒜素为武汉汇海公司产品,是从大蒜球茎中分离出的硫化物.Cell Counting Kit-8试剂购于上海同仁化学研究所,Bcl-2和Bax抗体及SP试剂盒购于福州迈新生物技术开发公司.方法:以含体积分数为0.1新生牛血清的1640完全培养基,培养LM-8细胞,制作细胞爬片.SP免疫细胞组织化学技术检测细胞爬片中Bcl-2和Bax蛋白表达;倒置显微镜下观察5.0,10.0和15.0 mg/L质量浓度大蒜素作用前后LM-8细胞形态变化;将LM-8细胞调整至7.5×107L-1接种于96孔板,用1.0,5.0,10.0和15.0 mg/L质量浓度的大蒜素处理细胞,设立不加任何处理因素的对照组及不含细胞和药物的培养基空白组,孵育24,48,72 h后取出培养板,加入CCK-8测定吸光度值,计算LM-8细胞生长抑制率:以5.0,10.0和15.0 mg/L质量浓度大蒜素干预LM-8细胞24,48,72 h,消化离心收集细胞,以流式细胞仪分析细胞凋亡率的变化.主要观察指标:LM-8细胞中Bcl-2和Bax蛋白表达;LM-8细胞形态及增殖、凋亡情况.结果:①Bcl-2和Bax蛋白表达:大蒜素可以降低Bcl-2表达,增强Bax表达,经15.0mg/L大蒜素作用72h,Bcl-2和Bax蛋白表达阳性率及Bcl-2/Bax表达与对照组比较,差异有显著性意义(P＜0.01).②LM-8细胞的形态:经不同质量浓度大蒜素干预后均出现明显凋亡表现.③LM-8细胞的增殖:大蒜素能明显抑制LM-8细胞的增殖,当大蒜素浓度从1.0 mg/L增加到15.0 mg/L,LM-8细胞72 h时生长抑制率由(23.87±3.26)%增至(58.32±5.38)%,在72 h其药物半数抑制率浓度是11.09 mg/L.④LM-8细胞的凋亡:5.0,10.0和15.0 mg/L质量浓度的大蒜素作用72 h后可诱导LM-8细胞凋亡,且呈浓度依赖性(P＜0.05).结论:①大蒜素可抑制LM-8细胞增殖,该效应与大蒜素的浓度和时间有关.②大蒜素可诱导LM-8细胞凋亡,作用呈浓度依赖性.③大蒜素抑制LM-8细胞增殖和诱导LM-8细胞凋亡的机制可能与下调Bcl-2的表达和上调Bax的表达有关.