Composition and antifungal mechanism of essential oil from Chrysanthemum morifolium cv. Fubaiju

Effect of Extraction Methods on Chemical Characteristics and Bioactivity of Chrysanthemum morifolium cv. Fubaiju Extracts

Chrysanthemum morifolium cv. Fubaiju (CMF) is regarded as one of the three most renowned varieties of white Chrysanthemum in China, and different extraction methods have significant effects on its composition and activities. Therefore, six extractions were used in this study to assess the effects on extracts. The basic chemical composition showed that hot water extract (Hw) had the highest total phenolic content, alkali water immersion-assisted hot water extract (Al) had the highest content of protein, and enzyme-assisted hot water extract (Enz) had the highest content of carbohydrate. The UPLC-Q-Exactive-MS results evinced the presence of 19 small-molecule compounds, including chlorogenic acid, caffeic acid, tuberonic acid glucoside, luteolin-7-O-rutinoside, and other substances. In addition, the antioxidant test found that the Hw exhibited the best 1,1-diphenyl-2-picrylhydrazyl (DPPH) (82.05 ± 1.59 mM TE/mg) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) (61.91 ± 0.27 mM TE/mg) scavenging ability. The anti-glycation test demonstrated that Enz possessed the most pronounced inhibitory effect on glycation products, including fructosamine and advanced glycation end products (AGEs). Additionally, the Enz also exhibited the most significant inhibitory effect on the protein oxidation product N'-formylkynurenine. The correlation analysis revealed that there was a close relationship between antioxidant properties and glycation resistance of extracts, and tuberonic acid glucoside, 1,3-di-O-caffeoylquinic acid, 1,4-Dicaffeoylquinic acid, quercetin-7-O-β-D-glucopyranoside, and isochlorogenic acid B were key small molecule components that affected activities. In summary, the extracts of CMF can be regarded as an excellent antioxidant and anti-glycosylation agent.

Potato glycoside alkaloids exhibit antifungal activity by regulating the tricarboxylic acid cycle pathway of Fusarium solani

Fusarium solani is a pathogenic fungus that causes significant harm, leading to crop yield reduction, fruit quality reduction, postharvest decay, and other diseases. This study used potato glycoside alkaloids (PGA) as inhibitors to investigate their effects on the mitochondrial structure and tricarboxylic acid (TCA) cycle pathway of F. solani. The results showed that PGA could inhibit the colony growth of F. solani (54.49%), resulting in the disappearance of the mitochondrial membrane and the loss of contents. PGA significantly decreased the activities of aconitase (ACO), isocitrate dehydrogenase (IDH), α-ketoglutarate dehydrogenase (α-KGDH), succinate dehydrogenase (SDH), fumarase (FH), malate dehydrogenase (MDH), succinyl-CoA synthetase (SCS), and increased the activity of citrate synthase (CS) in F. solani. After PGA treatment, the contents of acetyl coenzyme A (CoA), citric acid (CA), malic acid (L-MA), and α-ketoglutaric acid (α-KG) in F. solani were significantly decreased. The contents of isocitric acid (ICA), succinyl coenzyme A (S-CoA), succinic acid (SA), fumaric acid (FA), and oxaloacetic acid (OA) were significantly increased. Transcriptomic analysis showed that PGA could significantly affect the expression levels of 19 genes related to TCA cycle in F. solani. RT-qPCR results showed that the expression levels of ACO, IDH, α-KGDH, and MDH-related genes were significantly down-regulated, and the expression levels of SDH and FH-related genes were significantly up-regulated, which was consistent with the results of transcriptomics. In summary, PGA can achieve antifungal effects by reducing the tricarboxylic acid cycle's flow and regulating key genes' expression levels. This study reveals the antifungal mechanism of PGA from the perspective of TCA cycle, and provides a theoretical basis for the development and application of PGA as a biopesticide.

Antifungal activity and mechanism of Litsea cubeba (Lour.) Persoon essential oil against the waxberry spoilage fungi Penicillium oxalicum and its potential application

Litsea cubeba essential oil (LCEO) is a broad-spectrum bacteriostatic substance produced from the fruit of the Litsea tree that has been used for the treatment of various diseases in China for thousands of years. Here, the antifungal activities of LCEO against 10 different fungi (Naganishia diffluens, Fusarium sacchari, Cladosporium tenuissimum, Fusarium proliferatum, Fusarium verticillioides, Fusarium subglutinans, Mucor racemosus, Penicillium oxalicum, Penicillium chrysogenum, and Aspergillus niger) that cause rot to waxberries were assessed. The chemical components of LCEO and its modes of action against P. oxalicum were investigated. Citral (32.62 %) was characterized as the main component of LCEO by gas chromatography-mass spectrometry. LCEO exhibited excellent antifungal activities against all 10 fungi. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration of LCEO against P. oxalicum were 2.24 and 4.48 g/L, respectively. Furthermore, LCEO (MIC) compromised membrane permeability and integrity, caused leakage of the cell components, and increased production of malondialdehyde and reactive oxygen species. Scanning electron microscopy and transmission electron microscopy indicated that the morphology and ultrastructure of the LCEO-treated hyphal cell membrane and organelles were severely damaged. Meanwhile, LCEO increased the shelf life of waxberries from 1-2 to 5-6 d. LCEO is a potential ecologically friendly alternative to commercial fungicides to inhibit postharvest fungal contamination of waxberries during shipment and storage.

Antifungal mechanism of rose, mustard, and their blended essential oils against Cladosporium allicinum isolated from Xinjiang naan and its storage application

AIMS

To reveal the inhibition mechanism of rose, mustard, and blended essential oils against Cladosporium allicinum isolated from Xinjiang naan, and investigate the effect of the three essential oils on oxidative damage and energy metabolism.

METHODS AND RESULTS

Rose and mustard essential oils significantly inhibited mycelial growth and spore viability in a dose-dependent relationship. After essential oil treatment, the cell membrane permeability was altered, and significant leakage of intracellular proteins and nucleic acids occurred. SEM observations further confirmed the disruption of cell structure. ROS, MDA, and SOD measurements indicated that essential oil treatment induced a redox imbalance in C. allicinum, leading to cell death. As for energy metabolism, essential oil treatment significantly reduced Na+K+-ATPase, Ca2+Mg2+-ATPase, MDH activity, and CA content, impairing metabolic functions. Finally, storage experiments showed that all three essential oils ensured better preservation of naan, with mustard essential oil having the best antifungal effect.

CONCLUSIONS

Rose and mustard essential oils and their blends can inhibit C. allicinum at multiple targets and pathways, destroying cell morphological structure and disrupting metabolic processes.

Encapsulation of carvone in chitosan nanoemulsion as edible film for preservation of slice breads against Aspergillus flavus contamination and aflatoxin B1 production

Aspergillus flavus is a common fungus causing bread spoilage by aflatoxin B1 (AFB1) production. Essential oil components are considered as effective antifungal agent; however, volatility and oxidative-instability limited their practical applications. The aim of this study was to fabricate novel chitosan nanoemulsion film incorporating carvone (carvone-Ne) for protection of bread slices against A. flavus and AFB1 contamination in storage conditions. The nanoemulsion was characterized by SEM, DLS, XRD, and FTIR analyses accompanying with sustained delivery of carvone. The carvone-Ne displayed better inhibition of A. flavus (0.5 µL/mL) and AFB1 production (0.4 µL/mL) over unencapsulated carvone along with promising antioxidant activity (p < 0.05). Destruction of ergosterol, mitochondrial-membrane-potential, ions leakage, deformities in methylglyoxal biosynthesis, and in-silico interaction of carvone with Afl-R protein emphasized the antifungal and antiaflatoxigenic mechanisms of action. Further, in-situ preservation potentiality of Carvone-Ne in bread slices with improved gas compositions, and acceptable sensory qualities strengthen its application as innovative packaging material for food preservation.

Anti-Malassezia Drug Candidates Based on Virulence Factors of Malassezia-Associated Diseases

Malassezia is a lipophilic unicellular fungus that is able, under specific conditions, to cause severe cutaneous and systemic diseases in predisposed subjects. This review is divided into two complementary parts. The first one discusses how virulence factors contribute to Malassezia pathogenesis that triggers skin diseases. These virulence factors include Malassezia cell wall resistance, lipases, phospholipases, acid sphingomyelinases, melanin, reactive oxygen species (ROS), indoles, hyphae formation, hydrophobicity, and biofilm formation. The second section describes active compounds directed specifically against identified virulence factors. Among the strategies for controlling Malassezia spread, this review discusses the development of aryl hydrocarbon receptor (AhR) antagonists, inhibition of secreted lipase, and fighting biofilms. Overall, this review offers an updated compilation of Malassezia species, including their virulence factors, potential therapeutic targets, and strategies for controlling their spread. It also provides an update on the most active compounds used to control Malassezia species.

Recent advancements on use of essential oils as preservatives against fungi and mycotoxins spoiling food grains

Spoilage of grains by mycotoxigenic fungi poses a great threat to food security and human health. Conventionally used chemical agents to prevent grain fungi contamination cause increasingly significant problems such as microbial resistance, residual toxicity and environmental unfriendliness. In recent years, plant essential oils (EOs) have become a hot spot in the research of control of grain fungi and mycotoxins, due to their extensive sources, non-toxicity, environmental friendliness and good antifungal efficiency. The current review aims to provide an overview of the prevention of fungi and mycotoxins in grain through EOs. The antifungal and toxin inhibition efficiency of different EOs and their effective components are investigated. The inhibition mechanism of EOs on fungi and mycotoxins in grains is introduced. The influence of EOs treatment on the change of grain quality is also discussed. In addition, the formulations and techniques used to overcome the disadvantages of EOs application are introduced. The results of recent studies have confirmed that EOs provide great potential for controlling common fungi and mycotoxins in grains, and enhancing quantity and quality safety of grains.

Advances in Controllable Release Essential Oil Microcapsules and Their Promising Applications

Essential oils (EOs) have emerged as natural and popular ingredients used in the preparation of safe and sustainable products because of their unique characteristics, such as antibacterial and antioxidant activity. However, due to their high volatility, poorly solubility in water, and susceptibility to degradation and oxidation, the application of EOs is greatly limited. One of the promising strategies for overcoming these restrictions is encapsulation, which involves in the entrapment of EOs inside biocompatible materials to utilize their controllable release and good bioavailability. In this review, the microencapsulation of the controllable release EOs and their applications are investigated. The focus is on the antimicrobial mechanism of various EOs on different bacteria and fungi, release mechanism of microencapsulated EOs, and preparation research progress of the controllable EOs microcapsules. In addition, their applications are introduced in relation to the food, textiles, agriculture, and medical fields.

The volatile flavor and the antioxidant properties of a novel chrysanthemum rice wine during natural aging

Chrysanthemum morifolium cv. Fubaiju, a traditional tea in southern China with high nutritional and health functions was used in this study. Optimized production conditions of a novel chrysanthemum rice wine (FRW) were obtained by the Box-Behnken design response surface experiment. FRW with best sensory quality was developed with 0.68% chrysanthemum, 0.79% Jiuqu and 0.81:1 liquid-to-solid ratio. Compared with rice wine (RW) control, the total phenolic and flavonoid contents, as well as antioxidant activity of the FRW increased significantly. GC-MS analysis showed that more flavor compounds including alcohols, aldehydes, acids, and esters were detected in FRW. During the aging process, it was found that the antioxidant substances, the antioxidant activity and the flavor substances decreased, with the wine body tending to be homogenized. After 6 months of storage, overall sensory quality of FRW was more harmonious, with special nectar taste, which dramatically improved the flavor characteristics and functionality compared with traditional RW.

Effects of Pectinase Pre-Treatment on the Physicochemical Properties, Bioactive Compounds, and Volatile Components of Juices from Different Cultivars of Guava

In this study, the physicochemical properties, antioxidant capacity, and volatile compounds of the juices of different guava cultivars before and after pectinase treatment were evaluated. The results showed that the guava juice of the small fragrant (SF) cultivar exhibited the highest ascorbic acid concentration (1761.09 mg/L), and the highest contents of total phenolics (329.52 mg GAE/L) and total flavonoids (411.13 mg RE/L) were both found in the juice of the watermelon red (WR) cultivar. After pectinase treatment, the juice yield and the titratable acid, sugar components, total phenolics and total flavonoids, and antioxidant capacity levels of the guava juices were all higher than those of the non-pectinase group. However, lower sensory evaluation scores were obtained in the pectinase-treated guava juices. Aldehydes and terpenoids were the main flavor components in the guava juices, which were responsible for the aroma of the juice, while their relative contents were different in the four cultivar guava juices. Furthermore, pectinase treatment could change the amounts and relative contents of volatile compounds in the guava juice. During the pectinase treatment process, the relative contents of the main aroma constituents in the guava juices were significantly decreased. The findings of this research provide valuable information for the processing of guava juice.

Fast and non-destructive discriminating the geographical origin of Hangbaiju by hyperspectral imaging combined with chemometrics

Hangbaiju is highly appreciated flower tea for its health benefits, and its quality and price are affected by geographical origin. Fast and accurate identification of the geographical origin of Hangbaiju is very significant for producers, consumers and market regulators. In this work, hyperspectral imaging combined with chemometrics, was used, for the first time, to explore and implement the geographical origin classification of Hangbaiju. The hyperspectral images in the spectral range of 410-2500 nm for 75 samples of five different origins were collected. As a versatile chemometrics tool, bagging classification tree-radial basis function (BAGCT-RBFN), compared with classification tree (CT), radial basis function network (RBFN), was applied to discriminate Hangbaiju samples from different origins. The results showed that BAGCT-RBFN based on optimal wavelengths yielded superior classification performances to CT and RBFN with full wavelengths. The recognition rates (RR) of the training and prediction sets by BAGCT-RBFN were 96.0 % and 92.0 %, respectively. Hyperspectral imaging combined with chemometric can be considered as a powerful, feasible and convenient tool for the classification of Hangbaiju samples from different origins. It promises to be a potential way for origin discriminant analysis and quality monitor in food fields.

Antifungal mechanism of essential oil against foodborne fungi and its application in the preservation of baked food

Baked food is one of the most important staple foods in people's life, but its shelf life is limited. In addition, the spoilage of baked food caused by microbial deterioration will not only cause huge economic losses, but also pose a serious threat to human health. At present, due to the improvement of consumers' health awareness, the use of chemical preservatives has been gradually restricted. Compared with other types of synthetic preservatives, essential oils are becoming more and more popular because they are in line with the current development trend of "green," "safety" and "health" of food additives. Therefore, in this paper, we first summarized the main factors affecting the fungal contamination of baked food. Then analyzed the antifungal activity and mechanism of essential oil. Finally, we comprehensively summarized the application strategy of essential oil in the preservation of baked food. This review is of great significance for fully understanding the antifungal mechanism of essential oils and promoting the application of essential oils in the preservation of baked food.

Antifungal and Antiaflatoxinogenic Effects of Cymbopogon citratus, Cymbopogon nardus, and Cymbopogon schoenanthus Essential Oils Alone and in Combination

The antifungal and antiaflatoxinogenic activities of the essential oils (EOs) from the leaves of Cymbopogon schoenanthus, Cymbopogon citratus, Cymbopogon nardus, and their pair combinations were investigated. Antifungal susceptibility and the efficacy of paired combinations of EOs were assessed using agar microdilution and checkerboard methods, respectively. Identification and quantification of chemical components of the EOs were carried out by gas chromatography-mass spectrometry and gas chromatography-flame ionization detector (GC-MS and GC-FID), respectively. Aflatoxins were separated and identified by High-Performance Liquid Chromatography (HPLC) and then quantified by spectrofluorescence. The EO of C. nardus exhibited the highest inhibitory activity against Aspergillus flavus and Aspergillus parasiticus. The combination of C. citratus and C. nardus and that of C. nardus and C. schoenanthus exhibited a synergistic effect against Aspergillus flavus and Aspergillus, respectively. Both C. citratus and C. schoenanthus EOs totally inhibited the synthesis of aflatoxin B1 at 1 µL/mL. C. citratus blocked the production of aflatoxins B2 and G2 at 0.5 µL/mL. Both C. citratus and C. schoenanthus totally hampered the production of the aflatoxin G1 at 0.75 µL/mL. The combination of C. citratus and C. schoenanthus completely inhibited the production of the four aflatoxins. The study shows that the combinations can be used to improve their antifungal and antiaflatoxinogenic activities.