Chemical Composition and Combinatory Antifungal Activities of Ammoides verticillata, Allium sativum and Curcuma longa Essential Oils Against Four Fungi Responsible for Tomato Diseases

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.

Diallyl Trisulfide, the Antifungal Component of Garlic Essential Oil and the Bioactivity of Its Nanoemulsions Formed by Spontaneous Emulsification

The aim of this study was to evaluate the chemical compounds of garlic essential oil (EO), and determine the antifungal efficacy of garlic EO and its major components, diallyl trisulfide and its nanoemulsions against wood-rotting fungi, Trametes hirsuta and Laetiporus sulphureus. GC-MS analysis revealed that the major constituents of garlic EO were diallyl trisulfide (39.79%), diallyl disulfide (32.91%), and diallyl sulfide (7.02%). In antifungal activity, the IC₅₀ value of garlic EO against T. hirsuta and L. sulphureus were 137.3 and 44.6 μg/mL, respectively. Results from the antifungal tests demonstrated that the three major constituents were shown to have good antifungal activity, in which, diallyl trisulfide was the most effective against T. hirsuta and L. sulphureus, with the IC₅₀ values of 56.1 and 31.6 μg/mL, respectively. The diallyl trisulfide nanoemulsions showed high antifungal efficacy against the examined wood-rotting fungi, and as the amount of diallyl trisulfide in the lipid phase increases, the antifungal efficacy of the nanoemulsions increases. These results showed that the nanoemulsions and normal emulsion of diallyl trisulfide have potential to develop into a natural wood preservative.

Curcuma longa L. Rhizome Essential Oil from Extraction to Its Agri-Food Applications. A Review

Curcuma longa L. rhizome essential oil is a valuable product in pharmaceutical industry due to its wide beneficial health effects. Novel applications in the agri-food industry where more sustainable extraction processes are required currently and safer substances are claimed for the consumer are being investigated. This review provides information regarding the conventional and recent extraction methods of C. longa rhizome oil, their characteristics and suitability to be applied at the industrial scale. In addition, variations in the chemical composition of C. longa rhizome and leaf essential oils regarding intrinsic and extrinsic factors and extraction methods are also analysed in order to select the most proper to obtain the most efficient activity. Finally, the potential applications of C. longa rhizome oil in the agri-food industry, such as antimicrobial, weedicide and a food preservative agent, are included. Regarding the data, C. longa rhizome essential oil may play a special role in the agri-food industry; however, further research to determine the application threshold so as not to damage crops or affect the organoleptic properties of food products, as well as efficient encapsulation techniques, are necessary for its implementation in global agriculture.