Ginkgo biloba L. exocarp petroleum ether extract inhibits methicillin-resistant Staphylococcus aureus by modulating ion transport, virulence, and biofilm formation in vitro and in vivo.

ETHNOPHARMACOLOGICAL RELEVANCE: As reported in the Ancient Chinese Medicinal Books, Ginkgo biloba L. fruit has been used as a traditional Chinese medicine for the treatment asthma and cough or as a disinfectant. Our previous study demonstrated that G. biloba exocarp extract (GBEE), an extract of a traditional Chinese herb, inhibits the formation of methicillin-resistant Staphylococcus aureus (MRSA) biofilms. However, GBEE is a crude extract that contains many components, and the underlying mechanisms of purified GBEE fractions extracted with solvents of different polarities are unknown. AIM OF THE STUDY: This study aimed to investigate the different components in GBEE fractions extracted with solvents of different polarities and their antibacterial effects and mechanisms against MRSA and Staphylococcus haemolyticus biofilms both in vitro and in vivo. METHODS: The components in different fractions were detected by high-performance liquid chromatography-high resolution mass spectrometry (HPLC-HRMS). Microbroth dilution assays and time growth curves were used to determine the antibacterial effects of the fractions on 15 clinical bacterial isolates. Crystal violet staining, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were utilized to identify the fractions that affected bacterial biofilm formation. The potential MRSA targets of the GBEE fraction obtained with petroleum ether (PE), denoted GBEE-PE, were screened by transcriptome sequencing, and the gene expression profile was verified by quantitative polymerase chain reaction (qPCR). RESULTS: HPLC-HRMS analysis revealed that the four GBEE fractions (extracted with petroleum ether, ethyl acetate, n-butanol, and water) contained different ginkgo components, and the antibacterial effects decreased as the polarity of the extraction solvent increased. The antibacterial activity of GBEE-PE was greater than that of the GBEE fraction extracted with ethyl acetate (EA). GBEE-PE improved H. illucens survival and reduced MRSA colonization in model mouse organs. Crystal violet staining and SEM and TEM analyses revealed that GBEE-PE inhibited MRSA and S. haemolyticus biofilm formation. Transcriptional analysis revealed that GBEE-PE inhibits MRSA biofilms by altering ion transport, cell wall metabolism and virulence-related gene expression. In addition, the LO2 cell viability and H. illucens toxicity assay data showed that GBEE-PE at 20 mg/kg was nontoxic. CONCLUSION: The GBEE fractions contained different components, and their antibacterial effects decreased with increases in the polarity of the extraction solvent. GBEE-PE limited MRSA growth and biofilm formation by affecting ion transport, cell wall synthesis, and virulence-related pathways. This research provides a more detailed overview of the mechanism by which GBEE-PE inhibits MRSA both in vitro and in vivo and suggests that GBEE-PE is a new prospective antimicrobial with the potential to be used in MRSA therapeutics in the future.

Complex population evolutionary history of four cold-tolerant Notopterygium herb species in the Qinghai-Tibetan Plateau and adjacent areas.

Historical geological and climatic events are the most important drivers of population expansions/contractions, range shifts, and interspecific divergence in plants. However, the species divergence and spatiotemporal population dynamics of alpine cold-tolerant herbal plants in the high-altitude Qinghai-Tibetan Plateau (QTP) and adjacent areas remain poorly understood. In this study, we investigated population evolutionary history of four endangered Notopterygium herb species in the QTP and adjacent regions. We sequenced 10 nuclear loci, 2 mitochondrial DNA regions, and 4 chloroplast DNA regions in a total of 72 natural populations from the 4 species, and tested the hypothesis that the population history of these alpine herbs was markedly affected by the Miocene-Pliocene QTP uplifts and Quaternary climatic oscillations. We found that the four Notopterygium species had generally low levels of nucleotide variability within populations. Molecular dating and isolation-with-migration analyses suggested that Notopterygium species diverged ~1.74-7.82 million years ago and their differentiation was significantly associated with recent uplifts of the eastern margin of the QTP. In addition, ecological niche modeling and population history analysis showed that N. incisum and N. franchetii underwent considerable demographic expansions during the last glacial period of the Pleistocene, whereas a demographic contraction and a expansion occurred for N. forrestii and N. oviforme during the antepenultimate interglacial period and penultimate glacial period, respectively. These findings highlight the importance of geological and climatic changes during the Miocene-Pliocene and Pleistocene as causes of species divergence and changes in population structure within cold-tolerant herbs in the QTP biodiversity hotspot.

In Vivo and In Vitro Anti-Arthritic Effects of Cardenolide-Rich and Caffeoylquinic Acid-Rich Fractions of Periploca forrestii.

Periploca forrestii Schltr. (P. forrestii) is a species used in Traditional Chinese Medicine (TCM) known as "Miao medicine", and has a long history of use in the treatment of rheumatism, rheumatoid arthritis (RA), and joint pain. The present study aimed to evaluate the anti-arthritis effects of the cardenolide-rich and caffeoylquinic acid-rich fractions (CDLFs and CQAFs) of P. forrestii in collagen-induced arthritic (CIA) rats, and defined the mechanisms of therapeutic action in MH7A cells treated with TNF-α. Serum rheumatoid factor (RF), TNF-α, IL-6, IL-1ß, PGE2, NO, SOD, and MDA were determined by ELISA or other commercially assay kits. Histopathological changes in ankle joint tissues were examined. The mRNA expressions of IL-1ß, IL-6, COX-2, and iNOS in MH7A cells were measured by qRT-PCR assays. In addition, the expressions of iNOS, COX-2, and p65 proteins, and the phosphorylation of IκBα, p38, ERK1/2, and JNK proteins in MH7A cells were analyzed by Western blot. The results showed that CDLF and CQAF could suppress the paw swelling in CIA rats at different doses (125 mg/kg, 250 mg/kg, and 500 mg/kg). Histopathological examination suggests that the CDLF and CQAF significantly relieved the damage of the structure of the ankle joint in CIA rats. In addition, serum RF, TNF-α, IL-6, IL-1ß, PGE2, NO, and MDA were decreased, along with increased activity of serum SOD. Furthermore, CDLF and CQAF downregulated the expressions of IL-1ß, IL-6, COX-2, iNOS, and p65, and inhibited the phosphorylation of IκBα, p38, ERK1/2, and JNK in MH7A cells treated with TNF-α. These findings demonstrated that both CDLF and CQAF exhibited anti-arthritic activity, which might be associated with their inhibitory effects on the NF-κB and MAPK signaling pathways.

High-quality triplicate electrocardiogram monitoring in a first-in-man study: potential for early detection of drug-induced QT prolongation.

BACKGROUND: QT interval prolongation is associated with an increased risk of potentially fatal ventricular tachycardias, including torsade de pointes. Regulatory guidance recommends the "thorough QT/QTc" (TQT) study as the gold standard for assessing the propensity of novel nonantiarrhythmic drugs to delay cardiac repolarization. An opportunity exists, however, to use high-quality electrocardiogram (ECG) data from first-in-man trials as an exploratory and complementary approach to gain early insight into potential risk of QT prolongation. METHODS: We collected high-quality, triplicate, 12-lead ECG data during a first-in-man trial of a drug developed for the treatment of Type 2 diabetes that had shown in vitro hERG inhibition and potential to prolong QT intervals in an animal model. RESULTS: QTc prolongation was observed at the highest dose, leading to a maximum QTcF prolongation > 19 ms at 6 hours after the 14th daily dose. QTcF increases from time-matched baseline relative to placebo were positively correlated with peak plasma concentrations. CONCLUSIONS: Clinically relevant QT interval prolongations can be detected during first-in-man studies using high-quality ECG monitoring. Such data may facilitate early decision making on whether to terminate the development of a compound and invest resources in more promising molecules; and it may enable more efficient TQT study design or preclude the need for future TQT studies.