Synergistic and antimicrobial properties of commercial turmeric (Curcuma longa) essential oil against pathogenic bacteria

Recent advances in delivering free or nanoencapsulated Curcuma by-products as antimicrobial food additives

Food commodities are often contaminated by microbial pathogens in transit or during storage. Hence, mitigation of these pathogens is necessary to ensure the safety of food commodities. Globally, researchers used botanicals as natural additives to preserve food commodities from bio-deterioration, and advances were made to meet users' acceptance in this domain, as synthetic preservatives are associated with harmful effects to both consumers and environments. Over the last century, the genus Curcuma has been used in traditional medicine, and its crude and nanoencapsulated essential oils (EOs) and curcuminoids were used to combat harmful pathogens that deteriorate stored foods. Today, more research is needed for solving the problem of pathogen resistance in food commodities and to meet consumer demands. Therefore, Curcuma-based botanicals may provide a source of natural preservatives for food commodities that satisfy the needs both of the food industry and the consumers. Hence, this article discusses the antimicrobial and antioxidant properties of EOs and curcuminoids derived from the genus Curcuma. Further, the action modes of Curcuma-based botanicals are explained, and the latest advances in nanoencapsulation of these compounds in food systems are discussed alongside knowledge gaps and safety assessment where the focus of future research should be placed.

Antibacterial, bacteriolytic, and antibiofilm activities of the essential oil of temu giring (Curcuma heyneana Val.) against foodborne pathogens

Foodborne pathogens may cause foodborne illness, which is among the major health problems worldwide. Since the therapeutic options for the treatment of the disease are becoming limited as a result of antibacterial resistance, there is an increasing interest to search for new alternatives of antibacterial. Bioactive essential oils from Curcuma sp become potential sources of novel antibacterial substances. The antibacterial activity of Curcuma heyneana essential oil (CHEO) was evaluated against Escherichia coli, Salmonella typhi, Shigella sonnei, and Bacillus cereus. The principal constituents of CHEO are ar-turmerone, β-turmerone, α-zingiberene, α-terpinolene, 1,8-cineole, and camphor. CHEO exhibited the strongest antibacterial activity against E. coli with a MIC of 3.9 µg/mL, which is comparable to that of tetracycline. The combination of CHEO (0.97 µg/mL) and tetracycline (0.48 µg/mL) produced a synergistic effect with a FICI of 0.37. Time-kill assay confirmed that CHEO enhanced the activity of tetracycline. The mixture disrupted membrane permeability of E. coli and induced cell death. CHEO at MIC of 3.9 and 6.8 µg/mL significantly reduced the formation of biofilm in E. coli. The findings suggest that CHEO has the potential to be an alternative source of antibacterial agents against foodborne pathogens, particularly E. coli.

Development of fish gelatin/carrageenan/zein bio-nanocomposite active-films incorporated with turmeric essential oil and their application in chicken meat preservation

Gelatin/carrageenan (Ge/Car) active packaging films incorporated with turmeric essential oil (TEO) encapsulated in zein nanoparticles (ZNP) were developed. The efficacy of these active packaging films and their antimicrobial properties were also investigated to ensure their practical application. Three different types of nanocomposite films (Ge/Car, Ge/Car/TEO, and Ge/Car/ZNP) were prepared. The characterization of the films was elucidated using Fourier transform infrared (FTIR), X-ray diffraction analyses (XRD), and scanning electron microscope (SEM). Physicochemical and mechanical properties of the films were enhanced, owing to the application of TEO-containing nanocomposites. Supercritical-CO₂ extracted TEO showed excellent biological activities, alongside GC-MS analysis identified that TEO contained 33 bioactive compounds where the major constituent was Zingiberene. ZNP proved an excellent carrier of TEO. The nanocomposite film sustainably released TEO, improving the shelf life of the chicken meat by reducing bacterial colonies from 3.08 log CFU/g to 2.81 log CFU/g after 14 days incubation against Salmonella enterica compared with 6.66 log CFU/g observed in the control film. The overall results of this study suggest that the nanocomposite active film is an excellent candidate for food packaging to ensure a better world.

A Comparative Study on Chemical Compositions and Biological Activities of Four Amazonian Ecuador Essential Oils: Curcuma longa L. (Zingiberaceae), Cymbopogon citratus (DC.) Stapf, (Poaceae), Ocimum campechianum Mill. (Lamiaceae), and Zingiber officinale Roscoe (Zingiberaceae)

Essential oils (EOs) and their vapour phase of Curcuma longa (Zingiberaceae), Cymbopogon citratus (Poaceae), Ocimum campechianum (Lamiaceae), and Zingiber officinale (Zingiberaceae) of cultivated plants grown in an Amazonian Ecuador area were chemically characterised by Gas Chromatography-Flame Ionization Detector (GC-FID), Gas Chromatography-Mass Spectrometry (GC-MS), and Head Space-Gas Chromatograph-Flame Ionization Detector-Mass Spectrometry (HS-GC-FID-MS).figure The EOs analyses led to the identification of 25 compounds for C. longa (99.46% of the total; ar-turmerone: 23.35%), 18 compounds for C. citratus (99.59% of the total; geraniol: 39.43%), 19 compounds for O. campechianum (96.24% of the total; eugenol: 50.97%), and 28 for Z. officinale (98.04% of the total; α-Zingiberene: 15.45%). The Head Space fractions (HS) revealed C. longa mainly characterised by limonene and 1,8-cineole (37.35%) and α-phellandrene (32.33%); Z. officinale and C. citratus showed camphene (50.39%) and cis-Isocitral (15.27%) as the most abundant compounds, respectively. O. campechianum EO revealed a higher amount of sesquiterpenes (10.08%), mainly characterised by E-caryophyllene (4.95%), but monoterpene fraction remained the most abundant (89.94%). The EOs were tested for antioxidant, antimicrobial, and mutagen-protective properties and compared to the Thymus vulgaris EO as a positive reference. O. campechianum EO was the most effective in all the bioactivities checked. Similar results emerged from assaying the bioactivity of the vapour phase of O. campechianum EO. The antioxidant and antimicrobial activity evaluation of O. campechianum EO were repeated through HP-TLC bioautography assay, pointing out eugenol as the lead compound for bioactivity. The mutagen-protective evaluation checked through Ames's test properly modified evidenced a better capacity of O. campechianum EO compared with the other EOs, reducing the induced mutagenicity at 0.1 mg/plate. However, even with differences in efficacy, the overall results suggest important perspectives for the functional use of the four studied EOs.

Evaluation of Antibacterial Activity of Extracts of Curcuma Longa L. Rhizome and Estimation of Curcuminoid by HPLC

Curcuma longa L. rhizome extracts have polyphenolic secondary metabolites called curcuminoid and various volatile oils. These compounds exhibit wide spectrum of antibacterial activity. Ethanol and petroleum ether C. longa rhizome extracts were studied for their antibacterial action against two bacteria, Escherichia coli and Staphylococcus aureus. This activity had evaluated by employing Agar Well Diffusion method. Curcuminoid was interpreted by pattern of High Performance Liquid Chromatography (HPLC). The ethanol extract exhibited inhibitory effects against E. coli and S. aureus at concentration 150 mg/ml with diameter of inhibition zone (23.000 ± 0.57735 and 27.000 ± 0.57735mm) respectively. On the contrary, petroleum ether extract had inhibitory effects for E. coli and S. aureus at concentration 150 mg/ml in diameter of inhibition zone (39.000 ± 0.57735 and 41.000 ± 0.57735mm) respectively. Quantitative analysis for the curcuminoid compounds from C. longa rhizome extracts revealed highest curcumin, demethoxycurcumin and bisdemethoxycurcumin (9.12, 5.93 and 23.96 µg /ml) respectively in the extract of petroleum ether. We concluded that the C. longa extracts exhibited inhibitory effects against pathological bacterial growth. The essential oils obtained by petroleum ether extract of C. longa rhizome was more influential inhibition than ethanol extract against E. coli and S. aureus.

Antibacterial activity of curcumin and its essential nanoformulations against some clinically important bacterial pathogens: A comprehensive review

Multidrug-resistant bacterial infections can kill 700,000 individuals globally each year and is considered among the top 10 global health threats faced by humanity as the arsenal of antibiotics is becoming dry and alternate antibacterial molecule is in demand. Nanoparticles of curcumin exhibit appreciable broad-spectrum antibacterial activity using unique and novel mechanisms and thus the process deserves to be reviewed and further researched to clearly understand the mechanisms. Based on the antibiotic resistance, infection, and virulence potential, a list of clinically important bacteria was prepared after extensive literature survey and all recent reports on the antibacterial activity of curcumin and its nanoformulations as well as their mechanism of antibacterial action have been reviewed. Curcumin, nanocurcumin, and its nanocomposites with improved aqueous solubility and bioavailability are very potential, reliable, safe, and sustainable antibacterial molecule against clinically important bacterial species that uses multitarget mechanism such as inactivation of antioxidant enzyme, reactive oxygen species-mediated cellular damage, and inhibition of acyl-homoserine-lactone synthase necessary for quorum sensing and biofilm formation, thereby bypassing the mechanisms of bacterial antibiotic resistance. Nanoformulations of curcumin can thus be considered as a potential and sustainable antibacterial drug candidate to address the issue of antibiotic resistance.

Fabrication of chitosan-based food packaging film impregnated with turmeric essential oil (TEO)-loaded magnetic-silica nanocomposites for surimi preservation

Successful modification of chitosan (CS) film using magnetic-silica nanocomposite to encapsulate turmeric essential oil (TEO) obtained by super critical CO2 extraction for enhanced preservation of surimi was performed. TEO exhibited antioxidant and antibacterial activities against Bacillus cereus. The core magnetic nanoparticles (MNPs) were capped with porous silica (Si) to form core-shell nanocomposites, into which TEO was loaded with 75.24% encapsulation efficiency. The fabricated nanocomposite was characterized, blended with CS to cast a bionanocomposite active film and characterized for efficient impregnation of bionanocomposite. The physical and mechanical properties of film were significantly improved after adding MNPs/Si/TEO nanocomposite. Uncontrolled release of TEO from CS film resulted in bacterial growth after 6 days of storage whereas bionanocomposites exhibited a sustained release of TEO that controlled the microbial load from 4.0 log CFU/g to 2.78 log CFU/g over 14 days. The overall study demonstrated that the CS/MNPs/Si/TEO bionanocomposite film was efficient as a packaging material for prolonged shelf-life of surimi.

Turmeric Oil: Composition, Extraction, Potential Health Benefits and Other Useful Applications

The turmeric essential oil of Curcuma species has extensively more useful properties due to its rich phytochemical profile. The concentration of volatile chemical constituents varies according to their type of applied plant part (i.e., root, rhizome, leaves, and flower) for extraction and type of the adopted extraction method. Novel extraction and purification methods, subcritical CO2 , supercritical CO2 , pressurized liquid extraction, and molecular distillation are found to be more efficient for good recovery of this volatile oil, along with increased concentrations of specified compounds. Not only have the curcuminoid compounds had a broad potential in the field of pharmacology but also the turmeric oil is found to have great applicability in treating several diseases and disorders. Turmeric oil possesses good antioxidant, antimicrobial, anticancer, anti-hyperlipidemic anti-inflammatory, anti-diabetic, and hepato-protective properties. Apart from medicinal fields, this oil has also a great future in the cosmetics, pesticide, and food industries due to its rich chemical profile. The present review focuses on providing information about turmeric oil in terms of its physicochemical properties, chemical composition, and available traditional extraction techniques, as well as available novel extraction options, actual health benefits, and other useful applications. It is hoped that the reported information is helpful for further discovery in the area of food, pharmaceutical, and cosmeceutical applications.

Combined antibacterial effect of essential oils from three most commonly used Ethiopian traditional medicinal plants on multidrug resistant bacteria

Background

An alarm increase the rate of emerging and re-emerging of multidrug resistant bacteria have been caused great public health concern in the worldwide. They have been resisting for most or majority of currently available and affordable antibiotics and imposed socioeconomic catastrophe at global scale. As a result, there is utmost important to discover new or modify currently available antibiotics. The aim of this study was to evaluate combined antibacterial effect of essential oils obtained from Blepharis cuspidata, Boswellia ogadensis and Thymus schimper against multidrug resistance (MDR) Escherichia coli, Klebsiella pneumoniae and Methicillin resistant S. aureus.

Methods

Essential oil (EO) was extracted from the aerial part of B. cuspidata, B.ogadensis and T. schimper by steam distillation and stored in brown bottles at 4 °C. There were mixed in 1:1 ratio and adsorbed to disc and placed on MHA and measured their minimum inhibitory zone seeded with E. coli, K. pneumoniae and MRAS after 18-24 H. minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were measured by broth micro-dilution method. The interaction between EOs was determined by fractional inhibitory concentration index.

Results

The antibacterial potential of mixed oil depends on the doses and type of the EOs and bacteria species. The combined EOs of B.cuspidata and T.schimperi had inhibition zone (39 mm), its MIC and MBC value was 0.39 μl/ml against MRSA. It had inhibition zone (28-35 mm), MIC value 0.39–6.25 μl/ml and MBC (0.78–12.5 μl/ml) against MDR E. coli and K. pneumoniae. Whereas, combined effects of B. cuspidata and B. ogadensis had MIC values ranges from 0.78–6.25 μl/ml for E.coli and K. pneumoniae and 1.56 μl/ml for MRSA. There was strong synergistic effect between the combination of B.cuspidata and T.schimperi. This study revealed that gram negative bacteria were slightly less susceptible than gram positive.

Conclusions

This in vitro study of combined EOs has significant antibacterial effect than using each of them and even it was more potent antibacterial effect on MDR as compare to modern antibiotics. Hence, it can be applied to a pharmaceutical composition as modulator or adjuvant or precursor for synthesis of new antibiotic in future activities.