Antibiofilm Activity of Azadirachta indica and Catharanthus roseus and Their Synergistic Effects in Combination with Antimicrobial Agents against Fluconazole-Resistant Candida albicans Strains and MRSA

Staphylococcus aureus biofilm: Formulation, regulatory, and emerging natural products-derived therapeutics

Staphylococcus aureus can readily form biofilm which enhances the drug-resistance, resulting in life-threatening infections involving different organs. Biofilm formation occurs due to a series of developmental events including bacterial adhesion, aggregation, biofilm maturation, and dispersion, which are controlled by multiple regulatory systems. Rapidly increasing research and development outcomes on natural products targeting S. aureus biofilm formation and/or regulation led to an emergent application of active phytochemicals and combinations. This review aimed at providing an in-depth understanding of biofilm formation and regulation mechanisms for S. aureus, outlining the most important antibiofilm strategies and potential targets of natural products, and summarizing the latest progress in combating S. aureus biofilm with plant-derived natural products. These findings provided further evidence for novel antibiofilm drugs research and clinical therapies.

Catharanthus roseus (L.) G. Don counteracts the ampicillin resistance in multiple antibiotic-resistant Staphylococcus aureus by downregulation of PBP2a synthesis

It is essential to revisit the global biodiversity, search for ethnopharmacologically relevant plants, and unveil their untapped potential to overcome the complications associated while treating infections triggered by multiple antibiotic-resistant Staphylococcus aureus. Catharanthus roseus (L.) G. Don of the Apocynaceae family is a medicinal plant used for remedial purposes against infectious diseases from ancient times. In this study, we intended to evaluate the mechanism by which the ethanolic extract of C. roseus root (EECRR) causes the reversal of ampicillin resistance in S. aureus. To achieve this goal, we have stained EECRR-treated S. aureus with acridine orange, analysed DNA damage by comet assay, and studied the alteration of plasmid band pattern and expression of penicillin-binding protein 2a (PBP2a) protein. Experiments revealed better S. aureus killing efficiency of EECRR at its minimum inhibitory concentration (MIC) doses due to DNA damage and reducing plasmid band intensities along with a decline in the expression of PBP2a in EECRR-treated cells at half-MIC dose. EECRR proved to be an efficient growth inhibitor of S. aureus that reduces the expression of PBP2a. Therefore, EECRR can also render ampicillin-resistant S. aureus susceptible to the antibiotic.

Genome-wide identification and expression analysis of TCP family genes in Catharanthus roseus

Introduction

The anti-tumor vindoline and catharanthine alkaloids are naturally existed in Catharanthus roseus (C. roseus), an ornamental plant in many tropical countries. Plant-specific TEOSINTE BRANCHED1/CYCLOIDEA/PCF (TCP) transcription factors play important roles in various plant developmental processes. However, the roles of C. roseus TCPs (CrTCPs) in terpenoid indole alkaloid (TIA) biosynthesis are largely unknown.

Methods

Here, a total of 15 CrTCP genes were identified in the newly updated C. roseus genome and were grouped into three major classes (P-type, C-type and CYC/TB1).

Results

Gene structure and protein motif analyses showed that CrTCPs have diverse intron-exon patterns and protein motif distributions. A number of stress responsive cis-elements were identified in promoter regions of CrTCPs. Expression analysis showed that three CrTCP genes (CrTCP2, CrTCP4, and CrTCP7) were expressed specifically in leaves and four CrTCP genes (CrTCP13, CrTCP8, CrTCP6, and CrTCP10) were expressed specifically in flowers. HPLC analysis showed that the contents of three classic TIAs, vindoline, catharanthine and ajmalicine, were significantly increased by ultraviolet-B (UV-B) and methyl jasmonate (MeJA) in leaves. By analyzing the expression patterns under UV-B radiation and MeJA application with qRT-PCR, a number of CrTCP and TIA biosynthesis-related genes were identified to be responsive to UV-B and MeJA treatments. Interestingly, two TCP binding elements (GGNCCCAC and GTGGNCCC) were identified in several TIA biosynthesis-related genes, suggesting that they were potential target genes of CrTCPs.

Discussion

These results suggest that CrTCPs are involved in the regulation of the biosynthesis of TIAs, and provide a basis for further functional identification of CrTCPs.