In Vivo and in Vitro Mitigation of Salmonella Typhimurium Isolates by Fortunella Japonica Fruit Extract

The vast dissemination of resistance to different antibiotics among bacterial pathogens, especially foodborne pathogens, has drawn major research attention. Thus, many attempts have been made to reveal novel alternatives to the current antibiotics. Due to their variable pharmacologically active phytochemicals, plants represent a good solution for this issue. This study investigated the antibacterial potential of Kumquat or Fortunella japonica methanol extract (FJME) against Salmonella typhimurium clinical isolates. Gas chromatography coupled with mass spectrometry (GC/MS) characterized 39 compounds in FJME. Palmitic acid (15.386%) and cis-vaccenic acid (15.012%) are the major active constituents detected by GC/MS. Remarkably, FJME had minimum inhibitory concentrations from 128 to 512 µg/mL in vitro. In addition, a systemic infection model revealed the in vivo antibacterial action of FJME. The antibacterial therapeutic activity of FJME was noticed by improving the histological features of the liver and spleen. Moreover, there was a perceptible lessening (p < 0.05) of the levels of the oxidative stress markers (nitric oxide and malondialdehyde) using ELISA. In addition, the gene expression of the proinflammatory cytokine (interleukin 6) was downregulated. On the other hand, there was an upregulation of the anti-inflammatory cytokine (interleukin 10). Accordingly, future clinical investigations should be done to reveal the potential antibacterial action of FJME on other food pathogens.

Drying kinetics and physicochemical properties of kumquat under hot air and air-impingement jet dryings

Kumquat is famous for its unique flavor and nutritional value. In this study, the drying kinetics, moisture effective diffusivity, phytochemical properties, and antioxidant capacities of kumquat dried by hot air drying (HAD) and air-impingement jet drying (AIJD) were comparatively investigated. The results showed that drying rate, moisture effective diffusivity, and nutrient retention under AIJD were better than those under HAD. Fourteen polyphenols were identified by UPLC-QqQ-MS/MS in kumquat slices. The content of limonoid was significantly increased after AIJD. It was also found that high temperature contributed to a higher drying rate. However, most of the polyphenol components decreased at high drying temperatures. Accordingly, AIJD 60 °C was regarded as the optimum condition for kumquat drying. This work contributed to a better understanding of the drying character of kumquat under AIJD and showed the bioactive compounds and antioxidant activities are affected by drying methods.

Metabolic Profiling and Gene Expression Analysis Unveil Differences in Flavonoid and Lipid Metabolisms Between 'Huapi' Kumquat (Fortunella crassifolia Swingle) and Its Wild Type

To elucidate the mechanism underlying special characteristic differences between a spontaneous seedling mutant 'Huapi' kumquat (HP) and its wild-type 'Rongan' kumquat (RA), the fruit quality, metabolic profiles, and gene expressions of the peel and flesh were comprehensively analyzed. Compared with RA, HP fruit has distinctive phenotypes such as glossy peel, light color, and few amounts of oil glands. Interestingly, HP also accumulated higher flavonoid (approximately 4.1-fold changes) than RA. Based on metabolomics analysis, we identified 201 differential compounds, including 65 flavonoids and 37 lipids. Most of the differential flavonoids were glycosylated by hexoside and accumulated higher contents in the peel but lower in the flesh of HP than those of RA fruit. For differential lipids, most of them belonged to lysophosphatidycholines (LysoPCs) and lysophosphatidylethanolamines (LysoPEs) and exhibited low abundance in both peel and flesh of HP fruit. In addition, structural genes associated with the flavonoid and lipid pathways were differentially regulated between the two kumquat varieties. Gene expression analysis also revealed the significant roles of UDP-glycosyltransferase (UGT) and phospholipase genes in flavonoid and glycerophospholipid metabolisms, respectively. These findings provide valuable information for interpreting the mutation mechanism of HP kumquat.

Effects of air-impingement jet drying on drying kinetics and quality retention of tomato slices

The purpose was to explore the drying kinetics, the moisture effective diffusivities, color, total polyphenols, lycopene and antioxidant activities of dried tomato slices by air-impingement jet drying (AIJD). The results showed that high temperature increased the drying rate, and Modified Page model accurately predicted the AIJD characteristics of tomato slices. AIJD is better than hot air drying in shortening drying time, enhancing drying rate and decreasing the loss of total polyphenols, lycopene and antioxidant capacity of tomato slices. Tomato slices dried by AIJD also showed higher lightness and redness. Lycopene content and antioxidant activity of tomato slices dried by AIJD were increased by higher drying temperature. Based on experimental data, AIJD at 80 °C can be used in tomato drying process due to the advantages in drying efficiency and content of bioactive compounds. This study will provide helpful information for the production of high quality of dried tomato products.

Rapid and comprehensive profiling of α-glucosidase inhibitors in Buddleja Flos by ultrafiltration HPLC-QTOF-MS/MS with diagnostic ions filtering strategy

Buddleja Flos is used as yellow rice colorant and a well-known traditional Chinese medicine. But its biochemical profiling is still lack due to complex matrix. Here, ultrafiltration high-performance liquid chromatograph-quadrupole time-of-flight tandem mass spectrometry (HPLC-QTOF-MS/MS) with diagnostic ions filtering strategy was proposed for rapid and comprehensive investigation of its α-glucosidase inhibitors. As a result, 33 bioactive compounds (13 phenylethanoid glycosides and 20 flavonoids) were successfully screened and identified. In addition, α-glucosidase inhibitory activities of twenty-two references were verified. Six flavonoid aglycones (4, 28, and 30-33) showed excellent α-glucosidase inhibitory activities (IC₅₀, from 5.11 ± 0.85 to 32.49 ± 9.76 μg/mL), much higher than that of acarbose (IC₅₀, 195.49 ± 10.05 μg/mL). Five flavonoid-monoglycosides (7, 12, 13, 20, and 22) presented moderate inhibitory activities with IC₅₀ from 160.98 ± 23.19 to 249.37 ± 35.83 μg/mL. Results showcased the high efficiency of proposed strategy in profiling of bioactive compounds from natural products.

Traditional Small-Size Citrus from Taiwan: Essential Oils, Bioactive Compounds and Antioxidant Capacity

Background: The calamondin (Citrus microcarpa Bunge) and the kumquat (Fortunella crassifolia Swingle) are two small-size citrus fruits that have traditionally been consumed in Taiwan; however, there has been a lack of scientific research regarding the active compounds and functionalities of these fruits. Methods: Analysis of volatile composition of essential oil and phytosterol was carried out using Gas Chromatography–Mass Spectrometry (GC-MS). Flavonoid and limonoid were analyzed by High Performance Liquid Chromatography (HPLC). Moreover, antioxidant capacity from their essential oils and extracts were assessed in vitro. Results: The compositions of the essential oils of both fruits were identified, with the results showing that the calamondin and kumquat contain identified 43 and 44 volatile compounds, respectively. In addition, oxygenated compounds of volatiles accounted for 4.25% and 2.04%, respectively, consistent with the fact that oxygenated compounds are generally found in high content in citrus fruits. In terms of flavonoids, the calamondin exhibited higher content than the kumquat, with disomin-based flavonoids being predominant; on the other hand, phytosterol content of kumquat was higher than that of calamondin, with amyrin being the dominant phytosterol. Both of them contain high amounts of limonoids. The ethanol extracts and essential oils of small-sized citrus fruits have been shown to have antioxidant effects, with those effects being closely related to the flavonoid content of the fruit in question. Conclusions: The present study also reviewed antioxidant activity in terms of specific bioactive compounds in order to find the underlying biological activity of both fruits. The calamondin and kumquat have antioxidant effects, which are in turn very important for the prevention of chronic diseases.

Simultaneous quantitative determination of 11 sesquiterpene lactones in Jerusalem artichoke (Helianthus tuberosus L.) leaves by ultra high performance liquid chromatography with quadrupole time-of-flight mass spectrometry

A method of ultra high performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry was developed for the simultaneous quantification of 11 sesquiterpene lactones in 11 Jerusalem artichoke leaf samples harvested in a number of areas at different periods. The optimal chromatographic conditions were achieved on a ZORBAX Eclipse Plus C₁₈ column (3.0 × 150 mm, 1.8 μm) with linear gradient elution of methanol and water in 8 min. Quantitative analysis was carried out under selective ion monitoring mode. All of the sesquiterpene lactones showed good linearity (R² ≥ 0.9949), repeatability (relative standard deviations < 4.66%), and intra- and interday precisions (relative standard deviations < 4.52%) with an accuracy of 95.24-104.84%. The recoveries measured at three concentration levels varied from 95.07 to 104.87% with relative standard deviations less than 4.9%. The limit of detection and limit of quantitation for this method were 0.89-5.05 and 1.12-44.33 ng/mL, respectively. The results showed that the contents of sesquiterpene lactones varied significantly in the Jerusalem artichoke leaf samples from different areas. Among them, the content of sesquiterpene lactones in the sample collected from Dalian, Liaoning province was the highest and the early flowering period was considered to be the optimal harvest time.

Phenolic compounds and biological activities of small-size citrus: Kumquat and calamondin

Kumquat and calamondin are two small-size citrus fruits. Owing to their health benefits, they are traditionally used as folk medicine in Asian countries. However, the research on flavonoids and biological activities of kumquat and calamondin have received less attention. This review summarizes the reported quantitative and qualitative data of phenolic compositions in these two fruits. Effects of maturity, harvest time, various solvent extractions and heat treatment of phenolic compositions, and bioactivities were discussed; distributions of the forms of phenolic compounds existing in kumquat and calamondin were also summarized. Furthermore, biological activities, including antioxidant, anti-tyrosinase, antimicrobial, antitumor, and antimetabolic disorder effects, have also been discussed. Effective phenolic components were proposed for a certain bioactivity. It was found that C-glycoside flavonoids are dominant phenolic compounds in kumquat and calamondin, unlike in other citrus fruits. Up to now, biological activities and chemical characteristics of C-glycoside flavonoids in kumquat and calamondin are largely unknown.