Effects of Piper cubeba L. essential oil on methicillin-resistant Staphylococcus aureus: an AFM and TEM study

Cubeb (Piper cubeba L.): nutritional value, phytochemical profiling and dermacosmeceutical properties

Introduction

Cubeb, Piper cubeba L., has been used for centuries in traditional medicine and culinary practices, with a wide range of biological and pharmacological activities.

Objective

Herein, we determined the phytochemical profile, mineral, fatty acids, and amino acid contents of P. cubeba berries and assessed the dermacosmeceutical properties of their water extract and essential oil (EO). These included assessing their antioxidant and antibacterial activities as well as their in vitro inhibitory activities against tyrosinase and elastase enzymes. In addition, molecular docking and molecular dynamics studies were performed on the major identified compounds of the EO.

Results and discussion

A total of forty-three compounds belonging to organic acids, phenolic acids and flavonoids were found in the water extract, while 36 volatile compounds were identified in the EO with Z-isoeugenol, dihydroeugenol, β-pinene, E-caryophyllene, and 1,8-cineole as major constituents. The berries were found to be rich in sodium and iron, have moderate zinc content along with low contents of total nitrogen, phosphorus, and potassium. Amino acid analysis revealed a considerable concentration of isoleucine and phenylalanine, whereas 11,14,17-eicosatrienoic acid and linoleic acid were identified as the major fatty acids. In the DPPH and FRAP assays, the water extract elicited considerable antioxidant activity compared to the reference compounds. Enzyme inhibitory assays revealed that the EO had a potential to inhibit tyrosinase and elastase enzymes with IC50 values of 340.56 and 86.04 μg/mL, respectively. The water extract and EO completely inhibited the bacterial growth at MIC of 50 mg/mL and 20%, respectively. At sub-MIC concentrations, the extract and the EO substantially reduced the biofilm formation by up to 26.63 and 77.77%, respectively, as well as the swimming and swarming motilities in a dose-dependent manner. Molecular docking and molecular dynamics showed that the five main components of P. cubeba EO could be the major contributors to the elastase and tyrosinase inhibitory effect.

Conclusion

This study emphasizes the promising potential of P. cubeba as a valuable source of natural compounds that can be utilized for the development of innovative pharmaceuticals, dietary supplements, and dermacosmeceutical agents.

Iron-tannic acid nano-coating: A promising treatment approach for enhancing Lactococcus lactis antibiotic resistance

The objective of this study was to explore a novel methodology for the synthesis of nanocoated probiotics following their collection and cultivation under optimized conditions, in light of their significant contribution to human health. Probiotics are instrumental in sustaining immune health by modulating the gastrointestinal microbiota and facilitating digestion. However, the equilibrium they maintain can be adversely affected by antibiotic treatments. It is critical to investigate the vulnerability of probiotics to antibiotics, considering the potential implications. This research aimed to assess whether nanoparticle coating could augment the probiotics' resistance to antibiotic influence. A strain of Lactococcus lactis (L. lactis) was isolated, cultured, and comprehensively characterized utilizing state-of-the-art methodologies, including the VITEK® 2 compact system, VITEK® MS, and 16S rRNA gene sequencing. The nanoparticle coating was performed using iron (III) chloride hexahydrate and tannic acid, followed by an evaluation of the probiotics' resistance to a range of antibiotics. The analysis through scanning electron microscopy (SEM) and atomic force microscopy (AFM) demonstrated a partial nanoparticle coating of the probiotics, which was further supported by UV/Vis spectroscopy findings, suggesting enhanced resistance to standard antibiotics. The results revealed that this strain possesses a unique protein profile and is genetically similar to strains identified in various other countries. Moreover, nano-encapsulation notably increased the strain's resistance to a spectrum of standard antibiotics, including Benzylpenicillin, Teicoplanin, Oxacillin, Vancomycin, Tetracycline, Rifampicin, Erythromycin, and Clindamycin. These findings imply that nanoparticle-coated probiotics may effectively counteract the detrimental effects of extended antibiotic therapy, thus preserving their viability and beneficial influence on gastrointestinal health.

Current State of Knowledge Regarding WHO High Priority Pathogens-Resistance Mechanisms and Proposed Solutions through Candidates Such as Essential Oils: A Systematic Review

Combating antimicrobial resistance (AMR) is among the 10 global health issues identified by the World Health Organization (WHO) in 2021. While AMR is a naturally occurring process, the inappropriate use of antibiotics in different settings and legislative gaps has led to its rapid progression. As a result, AMR has grown into a serious global menace that impacts not only humans but also animals and, ultimately, the entire environment. Thus, effective prophylactic measures, as well as more potent and non-toxic antimicrobial agents, are pressingly needed. The antimicrobial activity of essential oils (EOs) is supported by consistent research in the field. Although EOs have been used for centuries, they are newcomers when it comes to managing infections in clinical settings; it is mainly because methodological settings are largely non-overlapping and there are insufficient data regarding EOs' in vivo activity and toxicity. This review considers the concept of AMR and its main determinants, the modality by which the issue has been globally addressed and the potential of EOs as alternative or auxiliary therapy. The focus is shifted towards the pathogenesis, mechanism of resistance and activity of several EOs against the six high priority pathogens listed by WHO in 2017, for which new therapeutic solutions are pressingly required.

Cubeb (Piper cubeba L.f.): A comprehensive review of its botany, phytochemistry, traditional uses, and pharmacological properties

Piper cubeba L.f. (Piperaceae), known as cubeb, is a popular traditional herbal medicine used for the treatment of many diseases, especially digestive and respiratory disorders. The plant is rich in essential oil, found mainly in fruits, and this makes it economically important. Many traditional utilizations have been also validated from the plant and its isolated compounds owing to their antioxidant, antibacterial, anti-inflammatory and anticancer effects. These biological activities are attributed to the phytochemicals (phenolic compounds, lignans and alkaloids) and the essential oil of the plant. The present work aims to provide an up-to-date review on the traditional uses, phytochemistry and pharmacology of the plant and discusses the future perspectives to promote its valorization for nutritional- and health-promoting effects.

Multidrug and Pan-Antibiotic Resistance—The Role of Antimicrobial and Synergistic Essential Oils: A Review

Bacterial resistance to antibiotics continues to be a grave threat to human health. Because antibiotics are no longer a lucrative market for pharmaceutical companies, the development of new antibiotics has slowed to a crawl. The World Health Organization reported that the 8 new bacterial agents approved since July 2017 had limited clinical benefits. While a cohort of biopharmaceutical companies recently announced plans to develop 2-4 new antibiotics by 2030, we needn’t wait a decade to find innovative antibiotic candidates. Essential oils (EOs) have long been known as antibacterial agents with wide-ranging arsenals. Many are able to penetrate the bacterial membrane and may also be effective against bacterial defenses such as biofilms, efflux pumps, and quorum sensing. EOs have been documented to fight drug-resistant bacteria alone and/or combined with antibiotics. This review will summarize research showing the significant role of EOs as nonconventional regimens against the worldwide spread of antibiotic-resistant pathogens. The authors conducted a 4-year search of the US National Library of Medicine (PubMed) for relevant EO studies against methicillin-resistant Staphylococcus aureus, multidrug-resistant (MDR) Escherichia coli, EO combinations/synergy with antibiotics, against MDR fungal infections, showing the ability to permeate bacterial membranes, and against the bacterial defenses listed above. EOs are readily available and are a needed addition to the arsenal against resistant pathogens.

The impact of Cymbopogon martinii essential oil on Cutibacterium (formerly Propionibacterium) acnes strains and its interaction with keratinocytes

OBJECTIVES

The human skin microbiota is mainly composed of bacteria belonging to the genera Staphylococcus, Cutibacterium, Micrococcus and Corynebacterium, but on the skin of the face and back, ca. 50% of the total microbiota is represented by the bacterium Cutibacterium acnes. The aim of this research was to evaluate the impact of C. martini EO and its major compound, geraniol, on C. acnes.

METHODS

The minimum inhibitory concentration against C. acnes strains, phenotypic changes and responses of the proteome was determined. In addition, was assessed the effect of compounds in RNA-binding assay, on C. acnes-exposed keratinocytes and on the C. acnes type distribution on shoulder skin.

KEY FINDINGS

The range of the MIC was 0.7 to 1.6 mg/ml for the three main C. acnes types. There were no cytotoxic effects of compounds in the absence or presence of C. acnes; after 7 days of exposure to C. martini EO, we could not detect a major shift of the C. acnes types on shoulder skin that was found to be dominated by C. acnes strains of types II and IA2.

CONCLUSIONS

Our work gives novel insight into the skin microbiota-interacting properties of C. martini EO.

Brevibacillus laterosporus isolated from the digestive tract of honeybees has high antimicrobial activity and promotes growth and productivity of honeybee's colonies

The development of novel antimicrobial drugs, as well as the discovery of novel compounds able to promote honeybee's growth, represents major challenges for modern entomology. The main aim of this study was to investigate whether Brevibacillus laterosporus isolated from the digestive tract of Saudi honeybees, Apis mellifera, was able to stimulate colony strength parameters of honeybees and to evaluate its ability to produce antimicrobial agents. Honeybees were collected in Dirab, Riyadh Region, Saudi Arabia, and microorganisms were isolated and identified by 16S ribosomal RNA analysis. Microscopic identification of the microorganism in its native state was facilitated by atomic force microscopy at high-resolution imaging. Active biological compounds were produced by submerged fermentation with B. laterosporus. The fermented broth was subjected to extraction and purification, and then semi-pure compounds were analyzed by gas chromatography-mass spectrometry. The effectiveness of the crude extract and semi-pure compounds as antimicrobial agents was evaluated by susceptibility assays. More than 22% of the microorganisms isolated from the digestive tract of healthy honeybees have been identified as B. laterosporus, this kind of species has a unique shape and morphological structure. The cyclic dipeptide cyclo(Leu-Pro) produced by B. laterosporus showed biological activity against several pathogenic microorganisms. Furthermore, the total counts of workers, closed brood, and open brood, as well as the production of bee pollen and honey, were better in honeybees treated with a B. laterosporus suspension. The data indicated that the B. laterosporus strain isolated from a healthy honeybee might be a novel probiotic and a producer of important biological compounds.

Antimicrobial activity and synergism of ursolic acid 3-O-α-L-arabinopyranoside with oxacillin against methicillin-resistant Staphylococcus aureus

The objective of the present study was to investigate the antibacterial activity of a single constituent, ursolic acid 3-O-α-L-arabinopyranoside (URS), isolated from the leaves of Acanthopanax henryi (Oliv.) Harms, alone and in combination with oxacillin (OXA) against methicillin-resistant Staphylococcus aureus (MRSA). A broth microdilution assay was used to determine the minimal inhibitory concentration (MIC). The synergistic effects of URS and OXA were determined using a checkerboard dilution test and time-kill curve assay. The mechanism of action of URS against MRSA was analyzed using a viability assay in the presence of a detergent and an ATPase inhibitor. Morphological changes in the URS-treated MRSA strains were evaluated via transmission electron microscopy (TEM). In addition, the producing penicillin-binding protein 2a (PBP2a) protein level was analyzed using western blotting. The MIC value of URS against MRSA was found to be 6.25 µg/ml and there was a partial synergistic effect between OXA and URS. The time-kill growth curves were suppressed by OXA combined with URS at a sub-inhibitory level. Compared to the optical density at 600 nm (OD600) value of URS alone (0.09 µg/ml), the OD600 values of the suspension in the presence of 0.09 µg/ml URS and 0.00001% Triton X-100 or 250 µg/ml N,N'-dicyclohexylcarbodiimide reduced by 56.6 and 85.9%, respectively. The TEM images of MRSA indicated damage to the cell wall, broken cell membranes and cell lysis following treatment with URS and OXA. Finally, an inhibitory effect on the expression of PBP2a protein was observed when cells were treated with URS and OXA compared with untreated controls. The present study suggested that URS was significantly active against MRSA infections and revealed the potential of URS as an effective natural antibiotic.