Antibacterial evaluation of garlic extracts on chitosan/starch packaging film using response surface methodology and its application for shelf-life extension of bell peppers (Capsicum annuum).

In this study, garlic extract (GE) was assessed as a potential additive in chitosan/starch (Ch/De) coatings, focusing on phenolic and flavonoid content analyses and antibacterial properties. Using response surface methodology approach, an optimization method was employed to achieve the optimal antibacterial formulation, with Ch, De, and GE identified as key variables in the Design of Experiment. Fourier transform infrared spectroscopy and X-ray diffraction analyses elucidated interactions among these primary components within the films, while thermogravimetric analysis confirmed the enhanced thermal stability of GE-coated film formulations (Ch/De/GE). The Ch/De/GE exhibited antibacterial efficacy against Escherichia coli (ATCC 25922) with an inhibition zone of 7.2 mm at optimized concentrations of 2% w/v Ch, 1.5% w/v starch, and 0.5% v/v GE. In silico molecular docking studies provided insights into GE's inhibitory role as an antibacterial agent. Evaluation of green and yellow bell peppers (Capsicum annuum) over 18 days showed that coated peppers maintained better visual appearance and mass stability, with a weight loss decrease of 40.54%-48.96%, compared to uncoated ones. Additionally, the Ch/De/GE coating effectively inhibited bacterial growth, reducing it by 1-1.23 log CFU, during the storage period. In conclusion, the Ch/De/GE coating effectively extends the shelf-life of bell peppers and maintains their quality, demonstrating its potential for use in food packaging to preserve perishable items. PRACTICAL APPLICATION: The optimized chitosan/starch/garlic extract (Ch/De/GE) film developed in this study shows promising potential for application in the food packaging industry, particularly in extending the shelf life of perishable items like bell peppers. Its enhanced antibacterial properties, along with its ability to maintain visual appearance and reduce weight loss, make it an effective natural preservative that could replace synthetic additives in food packaging. By incorporating this biodegradable film into packaging solutions, producers can offer safer, more sustainable products that meet consumer demand for natural and environmentally friendly options.

Mechanistic insight into the free radical scavenging and xanthine oxidase (XO) inhibitor potent of monoacetylphloroglucinols (MAPGs).

Three novel antioxidant candidates based on phenolic polyketide, monoacetylphloroglucinol (MAPG), a natural antibiotic compound produced by plant growth-promoting rhizobacteria (PGPR), Pseudomonas fluorescens F113 have been proposed. Initially, a green and highly efficient route to the synthesis of MAPG and its two analogues from phloroglucinol (PG) has been developed. Afterward, their rational mechanism of antioxidant activity has been investigated based on thermodynamic descriptors involved in the double (2H+/2e-) radical trapping processes. These calculations have been performed using the systematic density functional theory (DFT) method at the B3LYP/Def2-SVP level of theory in the gas phase and aqueous solution. Our findings reveal that the double formal hydrogen atom transfer (df-HAT) mechanism is preferred in the gas phase, while the double sequential proton loss electron transfer (dSPLET) mechanism is preferred in aqueous solution for all MAPGs. The 6-OH group represents the most favorable site for trapping radical species for all MAPGs, which is supported by the pKa values obtained from DFT calculations. The role of acyl substituents on the PG ring has been comprehensively discussed. The presence of acyl substituents has a strong influence on the thermodynamic parameters of the phenolic O-H bond in PG. These results are supported by frontier molecular orbitals (FMOs) analysis, where the addition of acyl substituents increases the chemical reactivity of MAPGs significantly. Based on molecular docking and molecular dynamic simulations (MDs), MAPGs are also predicted to be promising candidates for xanthine oxidase (XO) inhibition.HighlightsThe antioxidant activity of the three synthesized monoacetylphloroglucinols (MAPGs) has been investigated using the density functional theory (DFT) method.Acyl substituents increase the chemical reactivity and antioxidant activity of MAPGs.Double formal hydrogen atom transfer (df-HAT) is the preferred mechanism in the gas phase.Double sequential proton loss electron transfer (dSPLET) seems to be more favored in aqueous solution.MAPGs are expected to be promising xanthine oxidase (XO) inhibitors.

Investigation of the dual role of acyl phloroglucinols as a new hope for antibacterial and anti-SARS-CoV-2 agents employing integrated in vitro and multi-phase in silico approaches.

With the rapid spread of multi-drug-resistant bacteria and more infectious or aggressive variants of SARS-CoV-2, it is critical to develop drugs that can quickly adapt to evolving bacterial and viral mutations. In this study, encouraged by nature, we synthesized a series of phloroglucinol (PG) derivatives, acyl phloroglucinols (ACPLs) 2a-4c by mimicking the structure of the natural antifungal 2,4-diacetylphloroglucinol 3a (2,4-DAPG). According to the quantum chemical calculation, these compounds were expected to be exceptionally favourable for intermolecular interaction with protein receptors. Intriguingly, the in vitro study of Staphylococcus aureus (S. aureus) ATCC 25923 and Escherichia coli (E. coli) ATCC 25922, showed that the four ACPLs 3a-4a had good antibacterial activity and selectivity against gram-positive bacteria, S. aureus. These results were then supported by in silico molecular docking and molecular dynamics simulations (MDs) between these potent compounds and the S. aureus FtsA protein (PDB ID: 3WQU). Furthermore, with the aid of the knowledge base Virus-CKB along with the molecular docking study, it was found that the three ACPLs 4a-4c showed potential inhibitors against SARS-CoV-2 PLpro (PDB ID: 7CMD). Additionally, 100 ns of MDs was carried out in order to assess the stability behaviour of ACPLs at the docked site. Moreover, in silico ADME/T and drug likeness of all studied ACPLs were also predicted. Finally, shape-based screening of FDA-approved drugs was performed using the most prominent synthesized ACPLs as a template, enabling us to include several medications that could be utilized as antibacterial and antiviral drug candidates.Communicated by Ramaswamy H. Sarma.

Identification of potential bioactive natural compounds from Indonesian medicinal plants against 3-chymotrypsin-like protease (3CLpro) of SARS-CoV-2: molecular docking, ADME/T, molecular dynamic simulations, and DFT analysis.

An outbreak of SARS-CoV-2 (COVID-19) has caused a global health emergency, resulting in hundreds of millions of infections and millions of deaths globally since December 2019. Due to the lack of a particular medicine or treatment approach and the fast spread of the virus around the world, it is imperative to find effective pharmacological molecules to combat the virus. Herein, we carried out docking-based virtual screening of selected 49 bioactive phytochemicals from 20 medicinal plants used in Jamu, an Indonesian traditional herbal medicine along with the 3CLpro inhibitor N3 towards the 3CLpro enzyme of SARS-CoV-2. From a total of 49 bioactive phytochemicals, eleven compounds exhibited good binding affinity against 3CLpro of SARS-CoV-2 (-7.2 to -8.5 kcal/mol). Accordingly, only seven phytochemicals fully obeyed drug-likeness properties. Ultimately, it was observed that both Luteolin and Naringenin have significant interactions with both of the catalytic residues of 3CLpro through hydrogen bonds and hydrophobic interactions, respectively. The drug-like characteristics of Luteolin and Naringenin were also confirmed by pharmacokinetic investigations. Further, an investigation into molecular dynamics (MD) simulations were undertaken to ensure the ligands would remain stable within the binding pocket. Finally, density-functional theory (DFT) calculations revealed the following order for biochemical reactivity: Naringenin > Luteolin > N3. The oxygen and hydrogen atom regions of these investigated ligands are suitable for electrophilic and nucleophilic attacks, respectively. These two bioactive phytochemicals from Tamarindus indica (Luteolin and Naringenin) as well as Citrus aurantifolia (Naringenin) might be potential antagonists of 3CLpro of SARS-CoV-2.Communicated by Ramaswamy H. Sarma.

Valorisation of lemongrass essential oils onto chitosan-starch film for sustainable active packaging: Greatly enhanced antibacterial and antioxidant activity.

To meet the global demand for sustainability aspects, the past few decades have witnessed magnificent evidence in the pursuit of sustainable active food packaging. As part of our contribution, herein, we explored the utilization of chitosan (Ch) modified with Dioscorea hispida (Dh) starch and incorporated with lemongrass essential oil (LO) as an attempt to obtain a novel active packaging formulation of Ch/Dh/LO in food. To obtain the optimum formulation of Ch/Dh/LO, 15 experiments were designed using the Box-Behnken design (BBD) with Ch (1-2% w/v), Dh starch (0.5-1.5% w/v) and LO (0.25-0.75% v/v) against E. coli, S. typhi, S. aureus and S. epidermidis bacteria. The presence of LO caused enhancements in physical, mechanical, and thermal stability, along with the antimicrobial, and antioxidant activity. Additionally, molecular docking and molecular dynamic (MD) simulations of the active compounds in LO against the active site of the FtsA enzyme were provided to unveil the mechanism of antibacterial action. Ultimately, this result suggests hydrogen bonds and hydrophobic interactions are involved between the active compounds in LO and FtsA enzymes. In general, this research provides valuable information that sheds light on the pivotal role of LO in enhancing the mechanical, thermal, and biological properties of sustainable active food packaging-based Ch film.

Diacylphloroglucinol derivatives as antioxidant agents: green synthesis, optimisation, in vitro, and in silico evaluation.

Several derivatives of diacylphloroglucinol (3a-3c and 5a-5b) as an analogue of natural product compound 2,4-diacetylphloroglucinol 3a, were successfully synthesised in an excellent yield via a greener Friedel-Craft acylation using methanesulfonic acid (MSA) as a catalyst under an ultrasound-assisted condition. Operational simplicity, excellent yield, expedient metal-free synthesis, energy-efficient and mild reaction conditions are the outstanding advantages in this procedure. A scaled-up reaction also revealed the practical suitability of this newly developed procedure. The effects of several process variables on 3a were carefully accomplished using response surface methodology (RSM). Moreover, the green credentials of the present protocol have been assessed using several established green metrics and compared to relevant procedures. Along with the monomers, dimeric diacylphloroglucinols (6a-6e) were also synthesised and their in vitro antioxidant activity of these species were carried out. Furthermore, drug-likeness, density functional theory (DFT), and molecular docking studies were also established.

A greatly improved procedure for the synthesis of an antibiotic-drug candidate 2,4-diacetylphloroglucinol over silica sulphuric acid catalyst: multivariate optimisation and environmental assessment protocol comparison by metrics.

Efforts toward the development of a straightforward greener Gram-scale synthesis of the antibiotic compound 2,4-diacetylphloroglucinol (DAPG) have been developed. This beneficial procedure was accomplished through the Friedel-Crafts acylation of phloroglucinol over inexpensive heterogeneous silica sulphuric acid (SSA) catalyst via ultrasound-assisted (US) synthesis under solvent-free condition. The influences of various parameters such as temperature, catalyst loading, and reaction time on the reaction performance were analysed using a multivariate statistical modelling response surface methodology (RSM). A high yield of DAPG (95%) was achieved at 60 °C after 15-20 min reaction with the presence of 10% (w/w) SSA as the catalyst. Column chromatography-free and a Gram scale-up reaction also exhibited the practical applicability of this newly developed protocol. The SSA catalyst was recovered and recycled up to 10 consecutive runs with no appreciable loss of activity. A plausible mechanism for the Friedel-Crafts acylation of phloroglucinol is proposed. Moreover, an environmental assessment has been carried out over this present method and compared with several established literature using the EATOS software and the Andraos algorithm to assess the consumption of the substrates, solvents, catalysts, and the production of coupled products or by-products. In addition, their energy consumptions were also determined. The data collected showed that the present method is the most promising one, characterised by the highest environmental impact profile against all the other reported methods. The physicochemical properties of the synthesised DAPG were assessed and exhibited reasonable oral bioavailability drug property as determined by Lipinski's rules.