Essential oil composition and antimicrobial potential of aromatic plants grown in the mid-hill conditions of the Western Himalayas

Antibacterial effectiveness of trans-cinnamaldehyde against foodborne Enterobacteriaceae and its adjuvant effect with gentamicin

The Enterobacteriaceae family is recognized as a primary group of Gram-negative pathogens responsible for foodborne illnesses and is frequently associated with antibiotic resistance. The present study explores the natural-based compound trans-cinnamaldehyde (TC) against drug-resistant Enterobacteriaceae and its synergism with gentamicin (GEN) to address this issue. The research employs three strains of Escherichia coli, Klebsiella pneumoniae, and Enterobacter cloacae, previously isolated from shrimp. The antibacterial activity was evaluated by the disk diffusion method, microdilution test, kinetics of growth, and time-kill curve. In addition, the synergistic effect between TC/GEN was investigated by checkerboard assay. All strains showed sensitivity to TC with an inhibition zone diameter > 35 mm. The TC showed inhibitory and bactericidal action in the most tested bacteria around 625 μg/mL. Sub-inhibitory amounts (1/2 and 1/4 MIC) of TC interfered with the growth kinetics by lag phase extension and decreased the log phase. Time-kill curves show a reduction of viable cells after the first hour of TC treatment at bactericidal concentrations. The synergistic effect between TC/GEN was observed for E. coli and E. cloacae strains with FICi ranging from 0.15 to 0.50. These findings, therefore, suggest TC as a promising alternative in the fight against drug-resistant Enterobacteriaceae that can cause foodborne illnesses.

Exploring the Sustainable Exploitation of Bioactive Compounds in Pelargonium sp.: Beyond a Fragrant Plant

This review article aims to present an overview regarding the volatile compounds in different scented species of Pelargonium and their biological activities, immunomodulatory activity, cytotoxic activity, high larvicidal activity and ethnopharmacological uses. Although the Pelargonium genus includes many species, we focused only on the scented ones, with the potential to be used in different domains. Pelargonium essential oil showed great properties as antioxidant activity, antibacterial activity (against K. pneumonie, S. aureus or E. coli strains) and antifungal activity (against many fungi including Candida sp.), the responsible compounds for these properties being tannins, flavones, flavonols, flavonoids, phenolic acids and coumarins. Due to the existence of bioactive constituents in the chemical composition of fresh leaves, roots, or flowers of Pelargonium sp. (such as monoterpenoid compounds-citronellol, geraniol, linalool, and flavonoids-myricetin, quercetin and kaempferol), this species is still valuable, the bio-compounds representing the base of innovative substitutes in food processing industry, nutraceuticals, or preventive human or veterinary medicine (substitute of antibiotics). Highlighting the volatile chemical composition and properties of this scented plant aims to rediscover it and to emphasize the vast spectrum of health-promoting constituents for a sustainable approach. Future research directions should point to the application of plant biotechnology with a significant role in conservation strategy and to stimulate commercial interest.

The Volatile Organic Compounds of Streptomyces spp.: An In-Depth Analysis of Their Antifungal Properties

The study of volatile organic compounds (VOCs) has expanded because of the growing need to search for new bioactive compounds that could be used as therapeutic alternatives. These small molecules serve as signals to establish interactions with other nearby organisms in the environment. In this work, we evaluated the antifungal effect of VOCs produced by different Streptomyces spp. This study was performed using VOC chamber devices that allow for the free exchange of VOCs without physical contact between microorganisms or the diffusible compounds they produce. Antifungal activity was tested against Escovopsis weberi, a fungal pathogen that affects ant nest stability, and the results showed that Streptomyces spp. CS014, CS057, CS131, CS147, CS159, CS207, and CS227 inhibit or reduce the fungal growth with their emitted VOCs. A GS-MS analysis of volatiles produced and captured by activated charcoal suggested that these Streptomyces strains synthesize several antifungal VOCs, many of them produced because of the presence of E. weberi, with the accumulation of various VOCs determining the growth inhibition effect.