Dental plaque regrowth studies to evaluate chewing gum formulations incorporating magnolia bark extract

The glucotoxicity protecting effect of honokiol in human hepatocytes via directly activating AMPK

Introduction

Sustained hyperglycemia causes glucotoxicity, which has been regarded as a contributor to hepatocyte damage in type 2 diabetes (T2D) and its metabolic comorbidities. Honokiol is a natural biphenolic component derived from the dietary supplement Magnolia officinalis extract. This study aimed to investigate the effects of honokiol on glucose metabolism disorders and oxidative stress in hepatocytes and the underlying mechanisms.

Methods

HepG2 cells were treated with glucosamines (18 mM) to induce glucotoxicity as a diabetic complication model in vitro.

Results and discussion

Honokiol significantly increased glucose consumption, elevated 2-NBDG uptake, and promoted GLUT2 translocation to the plasma membrane in glucosamine-treated HepG2 cells, indicating that honokiol ameliorates glucose metabolism disorders. Furthermore, glucosamine-induced ROS accumulation and loss of mitochondrial membrane potential were markedly reduced by honokiol, suggesting that honokiol alleviated glucotoxicity-induced oxidative stress. These effects were largely abolished by compound C, an AMPK inhibitor, suggesting an AMPK activation-dependent manner of honokiol function in promoting glucose metabolism and mitigating oxidative stress. Molecular docking results revealed that honokiol could interact with the amino acid residues (His151, Arg152, Lys243, Arg70, Lys170, and His298) in the active site of AMPK. These findings provide new insights into the antidiabetic effect of honokiol, which may be a promising agent for the prevention and treatment of T2D and associated metabolic comorbidities.

Development and evaluation of a chewing gum containing antimicrobial peptide GH12 for caries prevention

The purpose of this study was to develop a chewing gum containing a novel antimicrobial peptide GH12 and evaluate its biocompatibility, antimicrobial activity, and caries-preventive effects in vivo and in vitro. GH12 chewing gum was developed using a conventional method and its extracts were prepared in artificial saliva. GH12 concentration in the extracts was determined by high-performance liquid chromatography; extracts were used for growth curve assay, time-kill assay, crystal violet staining assay, scanning electron microscopy, and Cell Counting Kit-8 assay. A rat caries model was established, and molars were treated topically with extracts for 5 weeks. Weight gain monitoring, hematoxylin-eosin staining, micro-computed tomography, and Keyes scoring were conducted. Significant inhibition of Streptococcus mutans growth and biofilm formation was observed. Extracts displayed low cytotoxicity against human gingival epithelial cells. No significant differences in weight gain or signs of harm to the mucosal tissues in any of the rats were observed. Keyes scores of caries lesions in the GH12 chewing gum group were lower than those of the negative control group. It was concluded that GH12 chewing gum showed good biocompatibility, antimicrobial activity, and caries-preventive effects, exhibiting great potential to prevent dental caries as an adjuvant to regular oral hygiene.

Identification of minor lignans, alkaloids, and phenylpropanoid glycosides in Magnolia officinalis by HPLC‒DAD‒QTOF-MS/MS

An effective strategy based on high-speed counter-current chromatography (HSCCC) knockout combination with HPLC-DAD-QTOF-MS/MS analysis were developed to identify minor lignans, alkaloids, and phenylpropanoid glycosides in M. officinalis. Petroleum ether/ethyl acetate/methanol/water (8:4:7:5, v/v/v/v) as solvent system was firstly selected to separate the crude extract of M. officinalis. Two major lignans, honokiol and magnolol were knocked out, and minor components were enriched. Then, five standards (honokiol, magnolol, magnocurarine, magnoflorine and acteoside) were used as examples to discuss their fragmentation patterns for structural identification. By comprehensive screening, sixteen lignans, nine alkaloids, six phenylpropanoid glycosides were unambiguously or tentatively identified by comparing their retention time, UV spectra, accurate mass and fragmentation patterns with standards or reported components. Eight of them, as far as was known, were discovered from M. officinalis for the first time. The proposed method might provide a model for the effective identification of minor components from complex herbs. Additionally, this study laid a foundation for the study of quality control, and clinical applications of M. officinalis.