Anti-infective potential of hydroalcoholic extract of Punica granatum peel against gram-negative bacterial pathogens [version 2; peer review: 1 approved, 2 approved with reservations]

Background: Punica granatum extracts have been prescribed in traditional medicine for management of a variety of disease conditions including microbial infections. Generation of scientific evidence for validation of P. granatum peel extract’s anti-pathogenic efficacy is required. Methods: Hydroalcoholic extract of P. granatum peel (PGPE), prepared by microwave assisted extraction method was evaluated for its quorum-modulatory potential against two different human-pathogenic bacteria viz. Chromobacterium violaceum and Pseudomonas aeruginosa. Results: This extract was able to modulate in vitro production of quorum sensing-regulated pigments in both these test bacteria at ≥5 μg/ml. Virulence traits of P. aeruginosa like haemolytic activity, and biofilm formation were negatively affected by the test extract, and it also made P. aeruginosa more susceptible to lysis by human serum. Antibiotic susceptibility of both test bacteria was modulated owing to pre-treatment with PGPE. Exposure of these test pathogens to PGPE (≥0.5 μg/ml) effectively reduced their virulence towards the nematode Caenorhabditis elegans. Repeated subculturing of P. aeruginosa on PGPE-supplemented growth medium did not induce resistance to PGPE in this notorious pathogen, and this extract was also found to exert a post-extract effect on P. aeruginosa. Individual constituent phytocompounds of PGPE were found to be less efficacious than the whole extract. PGPE seemed to interfere with the signal-response machinery of P. aeruginosa and C. violaceum. PGPE also exhibited notable prebiotic potential by promoting growth of probiotic strains- Bifidobacterium bifidum and Lactobacillus plantarum at ≤50 μg/ml. Conclusions: This study indicates PGPE to be an effective antipathogenic and prebiotic preparation, and validates its therapeutic use mentioned in traditional medicine. This study also emphasizes the need for testing any bioactive extract at broadest possible concentration range, particularly in vivo, so that an accurate picture of dose-response relationship can emerge

Prophylactic potential of a Panchgavya formulation against certain pathogenic bacteria [version 1; referees: 2 approved]

A Panchgavya preparation was evaluated for its prophylactic efficacy against bacterial infection, employing the nematode worm Caenorhabditis elegans as a model host. Worms fed with the Panchgavya preparation prior to being challenged with pathogenic bacteria had a better survival rate against four out of five test bacterial pathogens, as compared to the control worms. Panchgavya feeding prior to bacterial challenge was found to be most effective against Staphylococcus aureus, resulting in 27% (p=0.0001) better worm survival. To the best of our awareness, this is the first report demonstrating in vivo prophylactic efficacy of Panchgavya mixture against pathogenic bacteria

Postbiotic production: harnessing the power of microbial metabolites for health applications

Postbiotics, which are bioactive substances derived from the metabolic processes of beneficial microbes, have received considerable attention in the field of microbiome science in recent years, presenting a promising path for exploration and innovation. This comprehensive analysis looks into the multidimensional terrain of postbiotic production, including an extensive examination of diverse postbiotic classes, revealing their sophisticated mechanisms of action and highlighting future applications that might significantly affect human health. The authors thoroughly investigate the various mechanisms that support postbiotic production, ranging from conventional fermentation procedures to cutting-edge enzyme conversion and synthetic biology approaches. The review, as an acknowledgment of the field’s developing nature, not only highlights current achievements but also navigates through the problems inherent in postbiotic production. In order to successfully include postbiotics in therapeutic interventions and the production of functional food ingredients, emphasis is given to critical elements, including improving yields, bolstering stability, and assuring safety. The knowledge presented herein sheds light on the expanding field of postbiotics and their potential to revolutionize the development of novel therapeutics and functional food ingredients

Antipathogenic Potential of a Polyherbal Wound-Care Formulation (Herboheal) against Certain Wound-Infective Gram-Negative Bacteria

This study investigated antipathogenic efficacy of a polyherbal wound-healing formulation Herboheal against three multidrug-resistant strains of gram-negative bacterial pathogens associated with wound infections. Herboheal was evaluated for its quorum-modulatory potential against three different human-pathogenic bacteria, first in vitro through the broth dilution assay and then in vivo in the model host Caenorhabditis elegans. Herboheal at ≥0.1% v/v was able to inhibit (19–55%) in vitro production of quorum sensing-regulated pigments in all these bacteria and seemed to interfere with bacterial quorum sensing by acting as a signal-response inhibitor. This formulation could compromise haemolytic activity of all three bacteria by ∼18–69% and induced their catalase activity by ∼8–21%. Herboheal inhibited P. aeruginosa biofilm formation up to 40%, reduced surface hydrophobicity of P. aeruginosa cells by ∼9%, and also made them (25%) more susceptible to lysis by human serum. Antibiotic susceptibility of all three bacteria was modulated owing to pretreatment with Herboheal. Exposure of these test pathogens to Herboheal (≥0.025% v/v) effectively reduced their virulence towards the nematode Caenorhabditis elegans. Repeated subculturing of P. aeruginosa on the Herboheal-supplemented growth medium did not induce resistance to Herboheal in this mischievous pathogen, and this polyherbal extract was also found to exert a post-extract effect on P. aeruginosa, wherein virulence of the Herboheal-unexposed daughter cultures, of the Herboheal-exposed parent culture, was also found to be attenuated. Overall, this study indicates Herboheal formulation to be an effective antipathogenic preparation and validates its indicated traditional therapeutic use as a wound-care formulation

Anti-infective efficacy of Psidium guajava L. leaves against certain pathogenic bacteria [version 2; peer review: 2 approved]

Water extracts of Psidium guajava leaves prepared by three different extraction methods were compared with respect to their anti-infective activity against Pseudomonas aeruginosa and Staphylococcus aureus in the nematode host Caenorhabditis elegans. The water extract prepared by Microwave Assisted Extraction method was found to have better anti-infective activity, and its activity was further compared with hydroalcoholic extract prepared using the same extraction method against five different pathogenic bacteria. Both these extracts could attenuate virulence of P. aeruginosa, S. aureus, Serratia marcescens, and Chromobacterium violaceum, towards C. elegans. Anti-infective efficacy of P. guajava leaf extract seems partly to stem from its quorum-modulatory property, as it could modulate production of quorum sensing-regulated pigments in all the susceptible bacteria

Validation of the anti-infective potential of a polyherbal ‘Panchvalkal’ preparation, and elucidation of the molecular basis underlining its efficacy against Pseudomonas aeruginosa

Abstract Background A Panchvalkal formulation (Pentaphyte P-5®) mentioned in ancient texts of Indian traditional medicine was investigated for its anti-infective potential against Pseudomonas aeruginosa. Methods Effect of the test formulation on bacterial growth and pigment production was evaluated by broth dilution assay. In vivo efficacy was evaluated using Caenorhabditis elegans as the model host. Whole transcriptome approach was taken to study the effect of test formulation on bacterial gene expression. Results This formulation in vitro was found to be capable of affecting quorum sensing (QS)-regulated traits (pyocyanin, pyoverdine, biofilm) of Pseudomonas aeruginosa. In combination with antibiotics, it enhanced susceptibility of the test bacterium to antibiotics like cephalexin and tetracycline. Effect of Panchvalkal formulation (PF) on QS-regulated traits of P. aeruginosa was not reversed even after repeated exposure of the bacterium to PF. In vivo efficacy of PF was demonstrated employing Caenorhabditis elegans as the model host, wherein PF-treated bacteria were able to kill lesser worms than their extract-unexposed counterparts. Whole transcriptome study revealed that approximately 14% of the P. aeruginosa genome was expressed differently under the influence of PF. Conclusions Major mechanisms through which Panchvalkal seems to exert its anti-virulence effect are generation of nitrosative and oxidative stress, and disturbing iron and molybdenum homeostasis, besides interfering with QS machinery. This study is a good demonstration of the therapeutic utility of the ‘polyherbalism’ concept, so common in ayurved. It also demonstrates utility of the modern ‘omics’ tools for validating the traditional medicine i.e. ayuromics

Probiotics (Bacillus clausii) for Prevention of Late-onset Sepsis in Preterm Infants (<34 weeks): A Randomised Controlled Trial

Introduction: Late-onset Sepsis (LOS) causes significant morbidity and mortality in preterm infants. Probiotics have been suggested to improve the integrity of mucosal barrier by modifying the enteric microflora and suppress the overgrowth and translocation of pathogens in the gut, thus preventing lifethreatening infections. Although probiotics have a definite role in prevention of Necrotising Enterocolitis (NEC) in preterm neonates, their effect on prevention of LOS in preterm neonates is still uncertain. Aim: To evaluate the role of probiotics in reducing incidence of LOS in preterm neonates (<34 weeks). Materials and Methods: A double blinded randomised control trial was conducted in a tertiary care Neonatal Intensive Care Unit (NICU) in Karnataka, India between 1st January 2019 to 31st December 2019. Seventy haemodynamically stable preterm neonates, <34 weeks of Gestational Age (GA), were randomised into ‘Probiotic’ and ‘Placebo’ groups. The probiotic group (n=36) was prophylactically administered Bacillus clausii suspension at a dose of 2.5 mL per-oral (0.4×109 spores in 1 mL) BD with breast milk, from initiation of enteral feeds till seven days, discharge/ death/LOS, whichever was earlier. The placebo group (n=34) received breast milk with sterile water 2.5 mL peroral BD. All the neonates were investigated and managed as per standard hospital protocol. Primary outcome of the study was to find the incidence of LOS. Student’s t-test, Mann-Whitney U test, Chi-square test and Fisher’s exact test were used for statistical analysis. Results: There was no significant difference between the probiotic vs placebo group, with respect to incidence of LOS (11.11% vs 17.64%; (p>0.05)) and duration of hospital stay (10.86±3.19 vs 11.23±2.98 days; (p>0.05)). However, incidence of feed intolerance in the probiotic group (11.11%) was significantly less than that the other (26%) (p<0.05). Conclusion: Probiotics, prophylactically fed enterally, did not reduce the incidence of LOS but provide a promising strategy to prevent feed intolerance in premature neonate

Beneficial effects of biochar application on mitigating the drought and salinity stress implications on plants

Biochar, an amorphous and highly porous carbonaceous substance derived from the thermal decomposition of organic matter, has been empirically proven to enhance soil water retention capacity, mitigate soil salinity, and augment nutrient bioavailability. Consequently, these improvements exert a stimulating influence on the growth and development of medicinal plants. Numerous scientific investigations have corroborated that the incorporation of biochar into the cultivation of medicinal flora can lead to increased plant biomass, heightened photosynthetic efficiency, and augmented accumulation of bioactive compounds. Furthermore, the utilization of biochar exhibits the potential to curtail the necessity for chemical fertilizers, which can otherwise have deleterious effects on soil health and the environment. A comprehensive comprehension of biochar's prospective role as a sustainable, long-term strategy for augmenting the productivity and resilience of medicinal plant cultivation in arid and saline environments holds paramount importance for ensuring a consistent supply of medicinal plants in the forthcoming years. This review aims to delve into the mechanistic foundations underpinning the beneficial impacts of biochar on plant development and the accumulation of bioactive constituents. It also explores the feasibility of biochar as a sustainable instrument for enhancing the cultivation of medicinal plants under adverse environmental conditions

Anti-infective potential of castor oil and ricinoleic acid against selected human-pathogenic bacteria

This document contains results of our investigation on anti-infective activity of castor oil, and one of its phytoconstituents- ricinoleic acid