Browsing by Author "Li, Hua-Bin"

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    Bioactive compounds and biological functions of garlic (Allium sativum L.)
    (MDPI, 2019) Shang, Ao; Cao, Shi-Yu; Xu, Xiao-Yu; Gan, Ren-You; Tang, Guo-Yi; Corke, Harold; Mavumengwana, Vuyo; Li, Hua-Bin
    ENGLISH ABSTRACT: Garlic (Allium sativum L.) is a widely consumed spice in the world. Garlic contains diverse bioactive compounds, such as allicin, alliin, diallyl sulfide, diallyl disulfide, diallyl trisulfide, ajoene, and S-allyl-cysteine. Substantial studies have shown that garlic and its bioactive constituents exhibit antioxidant, anti-inflammatory, antibacterial, antifungal, immunomodulatory, cardiovascular protective, anticancer, hepatoprotective, digestive system protective, anti-diabetic, anti-obesity, neuroprotective, and renal protective properties. In this review, the main bioactive compounds and important biological functions of garlic are summarized, highlighting and discussing the relevant mechanisms of actions. Overall, garlic is an excellent natural source of bioactive sulfur-containing compounds and has promising applications in the development of functional foods or nutraceuticals for the prevention and management of certain diseases.
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    Inhibition of multidrug-resistant foodborne Staphylococcus aureus biofilms by a natural terpenoid (+)-nootkatone and related molecular mechanism
    (Elsevier, 2020-02) Farha, Arakkaveettil Kabeer; Yang, Qiong-Qiong; Kim, Gowoon; Zhang, Dan; Mavumengwana, Vuyo; Habimana, Olivier; Li, Hua-Bin; Corke, Harold; Gan, Ren-You
    Staphylococcus aureus, a foodborne pathogen, poses serious problems to the food industries owing to biofilm formation, and over 25% of the foodborne illnesses in China have been attributed to S. aureus only. Phytochemicals are widely used as anti-biofilm agents with promising efficacy, and most of them are widely available and safe. This study reported the anti-biofilm efficacy of (+)-nootkatone, a sesquiterpene ketone found in a common fruit grapefruit, against multidrug-resistant S. aureus and its potential molecular mechanism. (+)-Nootkatone exhibited bacteriostatic and bactericidal effects at 200 and 400 μg/mL, respectively, against S. aureus SJTUF 20758 and S. aureus ATCC 25923. Crystal violet staining indicated that (+)-nootkatone inhibited S. aureus biofilm formation (p < 0.05) at a sub-MIC of 50 μg/mL and reduced exopolysaccharide production. The thickness of biofilms was significantly reduced by (+)-nootkatone, which was supported by the light microscopy and confocal laser scanning microscopy. Growth curve of bacteria showed that the antibacerial activity of (+)-nootkatone was dose-dependent, and the sub-MIC concentrations did not affect the bacterial growth of planktonic cells. Besides, (+)-nootkatone affected the sliding motility of S. aureus. At 200 μg/mL, (+)-nootkatone led to the reduction of preformed biofilm mass by 50% and bacterial cell death of 79%, accompanied with a reduction of exopolysaccharide. The expression of biofilm-related genes, including sarA, icaA, agrA, RNAIII, and spa, was suppressed by (+)-nootkatone, as revealed by the transcriptional analysis. Additionally, MTT assay revealed that there was no toxicity of (+)-nootkatone to the human foreskin fibroblasts (HFF) cells. Therefore, (+)-nootkatone is a promising phytochemical against S. aureus biofilms, and has the potential to be used in food industry to fight against S. aureus-induced safety issues.