Total flavonoids from Potentilla kleiniana Wight et Arn inhibits biofilm formation and virulence factors production in methicillin-resistant Staphylococcus aureus (MRSA).

ETHANOPHARMACOLOGICAL RELEVANCE: Potentilla kleiniana Wight et Arn is a wide-spread wild plant in the mountainous areas in southern China. The whole herb has been used as a traditional herbal medicine to treat fever, arthritis, malaria, insect and snake bites, hepatitis, and traumatic injury. In vitro studies have reported the antibacterial activity use of the plant in traditional medicinal systems. AIM OF THE STUDY: The aim of this study was to investigate the inhibitory activity of total flavonoid from Potentilla kleiniana Wight et Arn (TFP) on methicillin-resistant Staphylococcus aureus (MRSA) in planktonic state and biofilm state. MATERIALS AND METHODS: Antibacterial activities of TFP on planktonic MRSA were determined by agar diffusion method, microtiter plate assay and time-kill curve assay. Electrical conductivity, membrane permeability, membrane potential and autoaggregation were analyzed to study TFP effects on planktonic MRSA growth. Crystal violet (CV) staining and confocal laser scanning microscopy (CLSM) were analyzed to study TFP effects on aggregation and maturation of MRSA biofilm. After TFP treatment, extracellular polymeric substances (EPS) production were examined. Morphological changes in planktonic and MRSA biofilm following TFP treatment were determined with scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Moreover, α-Toxin protein expression and adhesion-related gene expression were also determined. RESULTS: The minimum inhibitory concentration (MIC) of TFP against MRSA was 20 µg/mL. The agar diffusion method and time-kill curve assay results indicated that TFP inhibited planktonic MRSA growth. TFP treatment significantly inhibited planktonic MRSA growth by inhibiting autoaggregation, α-hemolysin activity, α-Toxin protein expression, but increasing electrolyte leakage, membrane permeability and membrane potential and impacting cell structure. Moreover, TFP treatment significantly inhibited aggregation and maturation on MRSA biofilm by decreasing surface hydrophobicity, EPS production and adhesion-related gene expression. CONCLUSION: The results of this trial provide scientific experimental data on the traditional use of Potentilla Kleiniana Wight et Arn for traumatic injury treatment and further demonstrate the potential of TFP to be developed as a novel anti-biofilm drug.

Anti-colorectal cancer effects of tripolinolate A from Tripolium vulgare.

Tripolinolate A (TLA) is recently identified as a new compound from a halophyte plant Tripolium vulgare and has been shown to have significant in vitro activity against the proliferation of colorectal cancer and glioma cells. This study was designed to further investigate the effects of TLA on the proliferation of human normal cells, and the apoptosis and cell cycle in colorectal cancer cells, and the growth of tumors in the colorectal cancer-bearing animals. The data obtained from this study demonstrated that: 1) TLA had much less cytotoxicity in the human normal cells than the colorectal cancer cells; 2) TLA remarkably induced apoptosis in the human colorectal cancer cells and blocked cell cycle at G2/M phase, and 3) TLA had significant anti-colorectal cancer activity in the tumor-bearing animals.

Polygonumosides A-D, stilbene derivatives from processed roots of Polygonum multiflorum.

Four new stilbene derivatives, polygonumosides A-D (1-4), were isolated from the processed roots of Polygonum multiflorum. Their structures were elucidated by spectroscopic analysis, including 1D and 2D NMR and ECD. Polygonumosides A (1) and B (2), possessing an unprecedented tetracyclic skeleton, were assigned as 2S- and 2R-2-(4-hydroxyphenyl)-9,10,11-trihydroxy-2H-benzo[c]furo[2,3-f]chromen-7(3H)-one-4-O-ß-d-glucopyranosides, respectively, while polygonumosides C (3) and D (4) were assigned as a pair of diastereomeric stilbene glucoside dimers.

Two new phenylpropanoid glycosides from the roots of Aruncus sylvester.

Two new phenylpropanoid glycosides, 1,3,4-tri-O-(E)-caffeoyl-ß-d-glucopyranoside (1) and 1,4-di-O-(E)-caffeoyl-ß-d-glucopyranoside (2), along with four known phenylpropanoid glycosides (3-6), were isolated from the roots of Aruncus sylvester. The structures of 1 and 2 were elucidated using various spectroscopic methods. Compounds 1 and 2 displayed significant scavenging activity of 2,2-diphenyl-1-picrylhydrazyl free radicals with IC50 values of 110 and 258 µM (ascorbic acid: IC50 = 574 µM).

Hexaoxygenated flavonoids from Pteroxygonum giraldii.

Two flavonoids with an unusual 2',4',5'-trisubstituted B-ring (1 and 2), four myricetin derivatives (3-methylmyricetin-3'-O-beta-D-xylopyranoside (3), myricetin-3-O-alpha-L-rhamnopyranoside, myricetin-3-O-beta-D-galactopyranoside, and 3-methylmyricetin), and myricetin were isolated from the roots of Pteroxygonum giraldii Damm. & Diels. Their structures were elucidated using various spectroscopic methods and acid hydrolysis. Compound 1 was a new flavonoid and the NMR spectroscopic data of compounds 2 and 3 are reported for the first time.