Oxidative damage by free radicals has been implicated in the pathogenesis of vascular disease in diabetes and hypertension. In the present study, the total antioxidant status in diabetic and hypertensive rats before and after treatment with garlic (Allium sativum) was determined. The total serum antioxidants were measured by a modified method reported earlier by Miller and coworkers. The reproducibility of the assay was confirmed by determining standard curves for the known antioxidants: trolox (a stable analog of vitamin E), glutathione and vitamin C with interassay correlation coefficients (R2, n = 10 in triplicate) of 0.9984, 0.9768 and 0.987, respectively, confirming the reliability and reproducibility of the assay. This assay was then used to determine total serum antioxidant levels of streptozotocin-induced diabetic rats and two-kidney one-clip hypertensive rats both before and after 3 weeks of treatment with an aqueous extract of garlic (500 mg/kg IP daily). The serum antioxidant levels of rats after 3 weeks of treatment were significantly higher (P < .001) than the pretreatment levels in both diabetic and hypertensive rats. The increased serum antioxidant levels were paralleled by a decrease in serum glucose in the garlic-treated diabetic rats and lowered systolic blood pressure in the garlic-treated hypertensive rats. We conclude from our study that (i) total antioxidants can be measured by a simple, reproducible, reliable assay and (ii) the total antioxidant status can be significantly improved by treatment with garlic.

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Garlic reduces blood pressure (BP) in two-kidney, one-clip (2K-1C) rats, and enhances nitric oxide (NO) synthesis in in vivo and in vitro experiments. NO is an important modulator of BP in the 2K-1C model. This study investigated the role of NO in the BP-lowering effect of garlic in the 2K-1C model. BP readings (mm Hg) were obtained from 2K-1C rats in 4 groups treated intraperitoneally for 2 wk with either normal saline (NS), garlic, L-nitroarginine-methylester (L-NAME), or L-NAME+garlic (n=4x5). BP was determined using the tail-cuff method and compared with data of 4 similarly treated groups of normal (unclipped) rats (NRs). The BP readings of NR groups were 120+/-3 mm Hg for the NS-treated group, 120+/-2 mm Hg for the garlic-treated group, 167+/-3 mm Hg for the L-NAME treated group (higher than NS or garlic, P<0.001) and 128+/-5 mm Hg for the garlic+L-NAME-treated group (lower than L-NAME, P<0.001). The BP readings of 2K-1C rat groups were: for the NS group, 169+/-6 mm Hg (higher than NRs, P<0.001); for the garlic group, 116+/-7 mm Hg (lower than NS, P<0.001); for the L-NAME group: 184+/-8 mm Hg (higher than garlic, P<0.001), and for the L-NAME+garlic group: 130+/-6 mm Hg (lower than garlic or NS, P<0.001). The data show that L-NAME increases the BP of both NRs and 2K-1C rats, with the rise more evident in the NRs (39 vs. 9%, respectively). Garlic counteracts the hypertensive effect of L-NAME in NRs as well as 2K-1C rats. We conclude that the BP-lowering effect of garlic in the rat 2K-1C model may be partly mediated through the NO pathway.

Background: Interaction of C. albicans with oral bacteria is crucial for its persistence, but also plays a potential role in the infection process. In the oral cavity, it grows as part of dental plaque biofilms. Even though growth and interaction of C. albicans with certain bacterial species has been studied, little is known about its biofilm growth in vitro in the simultaneous presence of Gram-negative and Gram-positive bacteria. The aim was to evaluate the growth of C. albicans in polymicrobial biofilms comprising oral Gram-negative and Gram-positive bacteria. Further, we also aimed to assess the potential of C. albicans in the Candida-bacteria polymicrobial biofilm to elicit cytokine gene expression and cytokine production from human blood cells. Results: C. albicans cell counts increased significantly up to 48 h in polymicrobial biofilms (p < 0.05), while the bacterial counts in the same biofilms increased only marginally as revealed by qPCR absolute quantification. However, the presence of bacteria in the biofilm did not seem to affect the growth of C. albicans. Expression of IL-8 gene was significantly (p < 0.05) higher upon stimulation from biofilm-supernatants than from biofilms in polymicrobial setting. On the contrary, TNF-α expression was significantly higher in biofilms than in supernatants but was very low (1-4 folds) in the monospecies biofilm of C. albicans. ELISA cytokine quantification data was in agreement with mRNA expression results. Conclusion: Persistence and enhanced growth of C. albicans in polymicrobial biofilms may imply that previously reported antagonistic effect of A. actinomycetemcomitans was negated. Increased cytokine gene expression and cytokine production induced by Candida-bacteria polymicrobial biofilms and biofilm supernatants suggest that together they possibly exert an enhanced stimulatory effect on IL-8 and TNF-α production from the host.

Background: Periodontitis, a chronic inflammatory oral infection is the outcome of disturbances in the homeostasis of the oral biofilm microbiota. A number of studies have found the occurrence of Prevotella species in elevated levels in periodontitis compared to healthy subjects. Even though different aspects of Prevotella as part of oral biofilm have been studied, in vitro biofilms formed by these species have not been characterized systematically. The objective of this study was to characterize biofilms formed by several Prevotella species and further to assess biofilm inhibition and detachment of preformed biofilms.Methods: Biofilms were grown in 24-well plates containing brucella broth in anaerobic conditions for 3 days, and were quantified using crystal violet staining. Images of SYTO 9 Green fluorescent stained biofilms were captured using confocal microscopy. Biofilm inhibition and detachment by proteinase and DNase I was tested. The biochemical characterization included quantification of proteins and DNA in the biofilms and biofilm-supernatants.Results:Prevotella loescheii, Prevotella oralis and Prevotella nigrescens showed highest biofilm formation. P. nigrescens formed significantly higher amounts of biofilms than P. loescheii (P = 0.005) and P. oralis (P = 0.0013). Inhibition of biofilm formation was significant only in the case of P. oralis when treated with proteinase (P = 0.037), whereas with DNase I treatment, the inhibition was not significant (P = 0.531). Overall, proteinase was more effective in biofilm detachment than DNase I. Protein and DNA content were higher in biofilm than the supernatant with the highest amounts found in P. nigrescens biofilm and supernatants. P. oralis biofilms appeared to secrete large amounts of proteins extracellularly into the biofilm-supernatants.Conclusion: Significant differences among Prevotella species to form biofilms may imply their variable abilities to get integrated into oral biofilm communities. Of the species that were able to grow as biofilms, DNase I and proteinase inhibited the biofilm growth or were able to cause biofilm detachment.