Tamarindus indica Extract as a Promising Antimicrobial and Antivirulence Therapy

Assessment of antibacterial activity, modes of action, and synergistic effects of Origanum vulgare hydroethanolic extract with antibiotics against avian pathogenic Escherichia coli

This study evaluates the antibacterial effectiveness of Origanum vulgare hydroethanolic extract, both independently and in combination with antibiotics, against Escherichia coli strains associated with avian colibacillosis-a significant concern for the poultry industry due to the rise of antibiotic-resistant E. coli. The urgent demand for new treatments is addressed by analyzing the extract's phytochemical makeup via High-Performance Liquid Chromatography (HPLC), which identified sixteen phenolic compounds. Antibacterial activity was determined through agar diffusion and the measurement of minimum inhibitory and bactericidal concentrations (MIC and MBC), showing moderate efficacy (MIC: 3.9 to 7.8 mg/mL, MBC: 31.2 to 62.4 mg/mL). Combining the extract with antibiotics like ampicillin and tetracycline amplified antibacterial activity, indicating a synergistic effect and highlighting the importance of combinatory treatments against resistant strains. Further analysis revealed the extract's mechanisms of action include disrupting bacterial cell membrane integrity and inhibiting ATPase/H+ proton pumps, essential for bacterial survival. Moreover, the extract effectively inhibited and eradicated biofilms, crucial for preventing bacterial colonization. Regarding cytotoxicity, the extract showed no hemolytic effect at 1 to 9 mg/mL concentrations. These results suggest Origanum vulgare extract, particularly when used with antibiotics, offers a promising strategy for managing avian colibacillosis, providing both direct antibacterial benefits and moderating antibiotic resistance, thus potentially reducing the economic impact of the disease on the poultry industry.

Sorbate metal complexes as newer antibacterial, antibiofilm, and anticancer compounds

BACKGROUND

The ineffectiveness of treatments for infections caused by biofilm-producing pathogens and human carcinoma presents considerable challenges for global public health organizations. To tackle this issue, our study focused on exploring the potential of synthesizing new complexes of Co(II), Cu(II), Ni(II), and Zn(II) with sorbic acid to enhance its antibacterial, antibiofilm, and anticancer properties.

METHODS

Four novel complexes were synthesized as solid phases by reacting sorbic acid with Co(II), Cu(II), Ni(II), and Zn(II). These complexes were characterized by various technique, including infrared spectra, UV-Visible spectroscopy, proton nuclear magnetic resonance (1H NMR), and thermal analysis techniques, including thermogravimetry (TG).

RESULTS

The data acquired from all investigated chemical characterization methods confirmed the chemical structure of the sorbate metal complexes. These complexes exhibited antibacterial and antibiofilm properties against both Gram-positive and Gram-negative bacteria. Furthermore, these complexes enhanced the antibacterial effects of commonly used antibiotics, such as gentamicin and imipenem, with fractional inhibitory concentration (FIC) indices ≤ 0.5. Notably, the Cu(II) complex displayed the most potent antibacterial and antibiofilm activities, with minimum inhibitory concentration (MIC) values of 312.5 µg/mL and 625.0 µg/mL for Bacillus cereus and Escherichia coli, respectively. Additionally, in vitro assays using the methyl thiazolyl tetrazolium (MTT) method showed inhibitory effects on the growth of the human colon carcinoma cell line (HCT-116 cells) following treatment with the investigated metal complexes. The IC50 values for Co(II), Cu(II), Zn(II), and Ni(II) were 3230 µg/mL, 2110 µg/mL, 3730 µg/mL, and 2240 µg/mL, respectively.

CONCLUSION

Our findings offer potential for pharmaceutical companies to explore the development of novel combinations involving traditional antibiotics or anticancer drugs with sorbate copper complex.

Investigating Sulforaphane's anti-virulence and anti-quorum sensing properties against Pseudomonas aeruginosa

Background

P. aeruginosa, a significant bacterium, can cause severe illness and resistance to antibiotics. Quorum sensing (QS) systems regulate virulence factors production. Targeting QS could reduce bacteria pathogenicity and prevent antibiotic resistance. Cruciferous vegetables contain sulforaphane, known for its anti-inflammatory, antioxidant, anticancer, and antimicrobial properties.

Aim

We aimed to examine the inhibitory influences of sulforaphane, at a sub-inhibitory concentration (¼ minimum inhibitory concentration, MIC), on virulence and QS in P. aeruginosa.

Materials and methods

The sulforaphane's anti-virulence actions at sub-inhibitory concentrations were explored in vitro and in vivo. A sub-MIC concentration of sulforaphane was combined with anti-pseudomonal drugs, and the results of this combination were assessed. The virtual affinity of sulforaphane for the receptors of QS was studied, and its effect on the expression of QS genes was quantified.

Results

Sulforaphane significantly decreased the biofilm formation, motility, ability to withstand oxidative stress, and the synthesis of virulence extracellular enzymes such as proteases, hemolysins, and elastase, as well as other virulence factors like pyocyanin. In addition, sulforaphane lessened the severity of P. aeruginosa infection in mice. Sulforaphane reduced the antipseudomonal antibiotics' MICs when used together, resulting in synergistic effects. The observed anti-virulence impacts were attributed to the ability of sulforaphane to inhibit QS via suppressing the QS genes' expression.

Conclusion

Sulforaphane shows promise as a potent anti-virulence and anti-QS agent that can be used alongside conventional antimicrobials to manage severe infections effectively. Furthermore, this study paves the way for further investigation of sulforaphane and similar structures as pharmacophores for anti-QS candidates.

Phytochemical analysis, GC-MS profile and determination of antibacterial, antifungal, anti-inflammatory, antioxidant activities of peel and seeds extracts (chloroform and ethyl acetate) of Tamarindus indica L

Tamarindus indica L., is widely used tree in ayurvedic medicine. Here, we aimed to understand the presence of important constituents in seeds and peel of Tamarind fruits and their biological activities. Hence, seeds and peel of Tamarind fruits are used for further extraction process by soxhlet method (chloroform and ethyl acetate solvents). Results suggest that the ethyl acetate extract (seeds) consists of terpenoids (72.29 ± 0.513 mg/g), phenolic content (68.67 ± 2.11 mg/g) and flavonoids (26.36 ± 2.03 mg/g) whereas chloroform extract (seeds) has terpenoids (42.29 ± 0.98 mg/g). Similarly, chloroform extract (peel) has terpenoids (25.96 ± 3.20 mg/g) and flavonoids (46.36 ± 2.03 mg/g) whereas ethyl acetate extract (peel) has terpenoids (62.93 ± 0.987 mg/g). Furthermore, anti-inflammation activity results revealed that the chloroform extract of peel was found to be more effective with IC50 of 226.14 µg/ml by protein denaturation analysis and with IC50 of 245.5 µg/ml on lipoxygenase inhibition activity. Chloroform extract (peel and seeds) shown better antioxidant activity using DPPH than ethyl acetate extract (peel and seeds). Ethyl acetate extract of seeds showed impressive potency by inhibiting the growth of fungus, Candida albicans. Additionally, ethyl acetate extract of seeds showed impressive potency inhibiting the growth of Escherichia coli than Bacillus cereus. GC-MS analysis shown the existence of diverse set of phytochemicals in each extract. Overall, comparative studies highlight the effectiveness of seeds extracts than peel extracts. Moreover, GC-MS results suggest that the seeds and peel extracts (chloroform and ethyl acetate) contains a wide range of compounds (including flavonoids, isovanillic acid, fatty acids and phenolic compounds) which can be utilized for therapeutic purpose.

Partnering essential oils with antibiotics: proven therapies against bovine Staphylococcus aureus mastitis

Introduction

There is an urgent need to develop therapeutic options for biofilm-producing Staphylococcus aureus (S. aureus). Therefore, the renewed interest in essential oils (EOs), especially carvacrol, linalool and eugenol, has attracted the attention of our research group.

Methods

Multidrug resistance and multivirulence profiles in addition to biofilm production of S. aureus strains isolated from cows with mastitis were evaluated using both phenotypic and genotypic methods. The antimicrobial and antibiofilm activities of EOs were tested using both in vitro and molecular docking studies. Moreover, the interactions between commonly used antibiotics and the tested EOs were detected using the checkerboard method.

Results

We found that all our isolates (n= 37) were biofilm methicillin resistant S. aureus (MRSA) producers and 40.5% were vancomycin resistant S. aureus (VRSA). Unfortunately, 73 and 43.2% of the recovered MRSA isolates showed multidrug resistant (MDR) and multivirulence patterns, respectively. The antimicrobial activities of the tested EOs matched with the phenotypic evaluation of the antibiofilm activities and molecular docking studies. Linalool showed the highest antimicrobial and antibiofilm activities, followed by carvacrol and eugenol EOs. Fortunately, synergistic interactions between the investigated EOs and methicillin or vancomycin were detected with fractional inhibitory concentration index (FICI) values ≤ 0.5. Moreover, the antimicrobial resistance patterns of 13 isolates changed to sensitive phenotypes after treatment with any of the investigated EOs. Treatment failure of bovine mastitis with resistant S. aureus can be avoided by combining the investigated EOs with available antimicrobial drugs.

Conclusion

We hope that our findings can be translated into a formulation of new pharmaceutical dosage forms against biofilm-producing S. aureus pathogens.