Anthocyanin accumulation, biosynthesis and antioxidant capacity of black sweet corn (Zea mays L.) during kernel development over two growing seasons

Grain actives modulate gut microbiota to improve obesity-related metabolic diseases: A review

Whole grain diet is considered to be related to the improvement of obesity, dyslipidemia, hypertension, hyperglycemia, diabetes, and other metabolic diseases. Many studies indicate that these active ingredients in grains can act as prebiotics to improve intestinal integrity and host metabolism, preventing obesity. In this review, the physiological role of gut microbiota (GM) in the human body and its relationship with obesity were first introduced. Subsequently, the interaction between naturally derived bioactive ingredients in grains and GM was discussed, and the research progress of different grains was made in improving obesity and related metabolic diseases by regulating GM. This article provides fundamental explanations for the regulation of whole grains on obesity by GM and novel potential for the development of whole grain functional foods.

Calcium and Magnesium Regulation of Kernel Sugar Content in Maize: Role of Endogenous Hormones and Antioxidant Enzymes

Ca and Mg are essential micronutrients for plant growth, and they play a crucial role in plant development and responses to adversity by influencing the activities of endogenous hormones and antioxidant enzymes. However, the specific mechanisms through which calcium (Ca) and magnesium (Mg) regulate the kernel sugar content through endogenous hormones and antioxidant enzymes remain unclear. In this study, we analyzed the impact of Ca and Mg on the physiology of maize leaves and kernel quality by determining the activities of antioxidant enzymes and endogenous hormones, and the kernel sugar content in maize leaves when supplemented with different levels of Ca and Mg. Our main findings were as follows: (1) Elevated Mg levels augmented superoxide dismutase (SOD) activity, bolstering antioxidant defenses, whereas low Ca and Mg levels diminished SOD activity. High Ca levels enhanced catalase (CAT) activity during kernel development. Low-Ca conditions stimulated gibberellin (GA) synthesis, while high-Ca and high-Mg conditions suppressed it. High Mg levels also elevated abscisic acid (ABA) levels, potentially improving stress tolerance. (2) High Ca levels increased the reducing sugar content in kernels, augmenting the energy supply, while both low and high Mg levels increased soluble sugars, with low Mg levels specifically enhancing the sucrose content, which is a critical energy reserve in plants. (3) CAT exerted a pivotal regulatory role in the sugar accumulation in maize kernels. GA, under the influence of Ca, modulated the sucrose and soluble sugar contents by inhibiting CAT, whereas ABA, under the influence of Mg, promoted CAT activity, thereby affecting the kernel sugar content. This study reveals a new mechanism through which the addition of Ca and Mg regulate the sugar content in maize kernels by affecting endogenous hormones and antioxidant enzyme activities. These findings not only enhance our understanding of the role of micronutrients in plant growth and development but also provide new strategies for improving crop yield and stress tolerance.

Insecticidal potential and risk assessment of diamide pesticides against Spodoptera frugiperda in maize crops

The effectiveness, tolerance, and safety of pesticides must be established before their scientific or rational. This study evaluates the field control efficacy of broflanilide, tetraniliprole, and chlorantraniliprole in combating Spodoptera frugiperda in maize crops, as well as the resistance of S. frugiperda to these three diamide pesticides after exposure. By assessing field control efficiency, toxicity, effects on development and reproduction, and detoxification enzyme activity of these diamide pesticides on S. frugiperda, highlights broflanilide's significant insecticidal potential. A highly sensitive and efficient method using QuEChERS/HPLCMS/MS was developed to simultaneously detect residues of these three pesticides on maize. Initial concentrations of broflanilide, tetraniliprole, and chlorantraniliprole ranged from 2.13 to 4.02 mg/kg, with their respective half-lives varying between 1.23 and 1.51 days. Following foliar application, by the time of harvest, the terminal residue concentrations of these pesticides were all under 0.01 mg/kg. Chronic dietary intake risk assessments and cumulative chronic dietary exposure for three pesticides indicated that the general population's terminal residue concentration was within acceptable limits. Not only does this research provide valuable insights into field control efficiency, insecticidal effects, resistance, residues, and risk assessment results of broflanilide, tetraniliprole, and chlorantraniliprole on maize, but additionally, it also paves the way for setting suitable Maximum Residue Limits (MRLs) values based on pre-harvest interval values, rational dosage, and application frequency.

Effects of slightly acidic electrolyzed water on the quality and antioxidant capacity of fresh red waxy corn during postharvest cold storage

Fresh red waxy corn is consumed worldwide because of its unique flavor and rich nutrients, but it is susceptible to deterioration with a short shelf life. This study explored the effect of slightly acidic electrolyzed water (SAEW) treatment on the quality and antioxidant capacity of fresh red waxy corn during postharvest cold storage up to 40 d. The SAEW treatment exhibited lower weight loss, softer firmness, and higher total soluble solids (TSS) and moisture content than the control group. Correspondingly, the SAEW maintained the microstructure of endosperm cell wall and starch granules of fresh red waxy corn kernels well, contributing to good sensory quality. Furthermore, SAEW effectively reduced the accumulation of H2O2 content, elevated the O2 -· scavenging ability, maintained higher CAT and APX activities, and decreased the decline of the flavonoids and anthocyanin during the storage. These results revealed that the SAEW treatment could be a promising preservation method to maintain higher-quality attributes and the antioxidant capacity of fresh red waxy corn during postharvest cold storage.

Unlocking Phenolic Potential: Determining the Optimal Grain Development Stage in Hull-Less Barley Genotypes with Varying Grain Color

Barley is rich in phenolic compounds, providing health benefits and making it a valuable addition to a balanced diet. However, most studies focus on these compounds at barley's final maturity, neglecting their synthesis during grain development and its impact on barley quality for food applications. This study investigates phenolic profiles during grain development in four hull-less barley genotypes with different grain colors, specifically bred for food applications. The objectives were to determine the phenolic profile and identify the optimal maturity stage for maximum phenolic content and antioxidant capacity. Using UPLC-MS/MS and in vitro antioxidant capacity assays, results show that total phenolic compounds decrease as grain matures due to increased synthesis of reserve components. Flavan-3-ols, phenolic acids, and flavone glycosides peaked at immature stages, while anthocyanins peaked at physiological maturity. The harvest stage had the lowest phenolic content, with a gradient from black to yellow, purple, and blue genotypes. Antioxidant capacity fluctuated during maturation, correlating positively with phenolic compounds, specially bound phenolic acids and anthocyanins. These findings suggest that early harvesting of immature grain can help retain bioactive compounds, promoting the use of immature barley grains in foods. To support this market, incentives should offset costs associated with decreased grain weight.

Phenolic Characterization of a Purple Maize (Zea mays cv. "Moragro") by HPLC-QTOF-MS and Study of Its Bioaccessibility Using a Simulated In Vitro Digestion/Caco-2 Culture Model

The present work aimed to characterize the phenolic and antioxidant content of the Argentinian purple maize "Moragro" cultivar. Additionally, the INFOGEST simulated in vitro digestion model was used to establish the effect of digestion on bioactive compounds. Finally, digestion samples were used to treat Caco-2 cells in the transwell model to better understand their bioavailability. Twenty-six phenolic compounds were found in purple maize cv. "Moragro", 15 nonanthocyanins and 11 anthocyanins. Several compounds were identified in maize for the first time, such as pyrogallol, citric acid, gallic acid, kaempferol 3-(6″-ferulylglucoside), and kaempferol 3-glucuronide. Anthocyanins accounted for 24.9% of total polyphenols, with the predominant anthocyanin being cyanidin-3-(6″ malonylglucoside). Catechin-(4,8)-cyanidin-3,5-diglucoside and catechin-(4,8)-cyanidin-3-malonylglucoside-5-glucoside were detected as characteristics of this American maize variety. Total polyphenol content (TPC; by the Folin-Ciocalteu method), HPLC-DAD/MSMS, and antioxidant activity [by DPPH and ferric-reducing antioxidant power (FRAP)] were evaluated throughout in vitro digestion. TPC, DPPH, and FRAP results were 2.71 mg gallic acid equivalents (GAE)/g, 24 μmol Trolox equiv/g, and 22 μmol Trolox eq/g, respectively. The in vitro digestion process did not cause significant differences in TPC. However, the antioxidant activity was significantly decreased. Moreover, the bioavailability of anthocyanins was studied, showing that a small fraction of polyphenols in their intact form was conserved at the end of digestion. Finally, a protective effect of digested maize polyphenols was observed in the Caco-2 cell viability. The results suggest that "Moragro" purple maize is a good source of bioavailable anthocyanins in the diet and an interesting source of this group of compounds for the food industry.

Loss function of NtGA3ox1 delays flowering through impairing gibberellins metabolite synthesis in Nicotiana tabacum

Flowering time, plays a crucial role in tobacco ecological adaptation besides its substantial influence on tobacco production and leaf quality. Meanwhile, it is sensitive to biotic or abiotic challenges. The plant hormones Gibberellins (GAs), controlling a number of metabolic processes, govern plants growth and development. In this study, we created a late flowering mutant HG14 through knocking out NtGA3ox1 by CRISPR/Cas9. It took around 13.0 and 12.1 days longer to budding and flowering compared to wild type Honghuadajinyuan. Nearly all of the evaluated agronomic characters deteriorated in HG14, showing slower growth and noticeably shorter and narrower leaves. We found that NtGA3ox was more prevalent in flowers through quantitative reverse transcription PCR analysis. Transcriptome profiling detected 4449, 2147, and 4567 differently expressed genes at the budding, flowering, and mature stages, respectively. The KEGG pathway enrichment analysis identified the plant-pathogen interaction, plant hormone signal transduction pathway, and MAPK signaling pathway are the major clusters controlled by NtGA3ox1 throughout the budding and flowering stages. Together with the abovementioned signaling pathway, biosynthesis of monobactam, metabolism of carbon, pentose, starch, and sucrose were enriched at the mature stage. Interestingly, 108 up- and 73 down- regulated DEGs, impairing sugar metabolism, diterpenoid biosynthesis, linoleic and alpha-linolenic acid metabolism pathway, were continuously detected accompanied with the development of HG14. This was further evidenced by the decreasing content of GA metabolites such as GA4 and GA7, routine chemicals, alkaloids, amino acids, and organic acids Therefore, we discovered a novel tobacco flowering time gene NtGA3ox1 and resolved its regulatory network, which will be beneficial to the improvement of tobacco varieties.

Integration of comparative transcriptomics and WGCNA characterizes the regulation of anthocyanin biosynthesis in mung bean (Vigna radiata L.)

Mung bean is a dual-use crop widely cultivated in Southeast Asia as a food and medicine resource. The development of new functional mung bean varieties demands identifying new genes regulating anthocyanidin synthesis and investigating their molecular mechanism. In this study, we used high-throughput sequencing technology to generate transcriptome sequence of leaves, petioles, and hypocotyls for investigating the anthocyanins accumulation in common mung bean variety as well as anthocyanidin rich mung bean variety, and to elucidate their molecular mechanisms. 29 kinds of anthocyanin compounds were identified. Most of the anthocyanin components contents were significantly higher in ZL23 compare with AL12. Transcriptome analysis suggested that a total of 93 structural genes encoding the anthocyanin biosynthetic pathway and 273 regulatory genes encoding the ternary complex of MYB-bHLH-WD40 were identified, of which 26 and 78 were differentially expressed in the two varieties. Weighted gene co-expression network analysis revealed that VrMYB3 and VrMYB90 might have enhanced mung bean anthocyanin content by inducing the expression of structural genes such as PAL, 4CL, F3'5'H, LDOX, and F3'H, which was consistent with qRT-PCR results. These findings are envisaged to provide a reference for studying the molecular mechanism of anthocyanin accumulation in mung beans.

Transcriptional regulation mechanism of flavonoids biosynthesis gene during fruit development in astragalus membranaceus

Astragalus membranaceus, as an important medicinal plant, are an excellent source of flavonoids. Flavonoid compounds in A. membranaceus have been widely used in medicine and supplement, but known of the molecular mechanism of flavonoid biosynthesis is still very few. Here, we analyzed the association between flavonoid content and gene expression pattern during six different fruit developmental stages. Sixteen gene expression trends were significantly identified, involving 8,218 genes. The gene expression trend in profile 0 was positively correlated with flavonoid content, while the gene expression trend in profile 79 was negatively correlated with flavonoid content at six developmental stages. The expression level of genes involved in the general phenylpropane pathway was higher than that of genes involved in the flavonoid biosynthesis pathway. A total of 37 genes involved in flavonoid synthesis were identified in A. membranaceus. The expression pattern of flavonoid-related genes was highly correlated with flavonoid content. Our study deepened the understanding of the flavonoid synthesis mechanism and provided useful resources for future studies on the high flavonoid molecular breeding of A. membranaceus.

Plant flavonoids: Classification, distribution, biosynthesis, and antioxidant activity

Flavonoids are a group of natural polyphenol substances abundant in vegetables, fruits, grains, and tea. As plant secondary metabolites, flavonoids play essential roles in many biological processes and responses to environmental factors in plants. Flavonoids are common in human diets and have antioxidant effects as well as other bioactivities (e.g., antimicrobial and anti-inflammatory properties), which reduce the risk of disease. Flavonoid bioactivity depends on structural substitution patterns in their C6-C3-C6 rings. However, reviews of plant flavonoid distribution and biosynthesis, as well as the health benefits of its bioactivity, remain scarce. Therefore, in the present review, we systematically summarize recent progress in the research of plant flavonoids, focusing on their biosynthesis (pathway and transcription factors) and bioactive mechanisms based on epidemic evidence, in vitro and in vivo research, and bioavailability in the human body. We also discuss future opportunities in flavonoid research, including biotechnology, therapeutic phytoproducts, and dietary flavonoids.

Colored Corn: An Up-Date on Metabolites Extraction, Health Implication, and Potential Use

Colored (orange, pink, red, purple, and blue) corn strongly attracted attention on its healthy properties mainly due to its anthocyanin and carotenoid composition which is also responsible for its pigmentation. The present review summarized the recent updates on the extraction and chemical characterization of the main plant secondary metabolites present in colored seeds, kernel, cob, husk, and silk. The main approaches used to stabilize the extracts have been discussed as well as their food and non-food uses. Both in vitro and in vivo (animal models) studies on the different effects (antibacterial, antimutagenic, antioxidant, and anti-inflammatory activities, effects on metabolic syndrome, diabetes, glucose and lipidic metabolism, and neuroprotection) of pigmented extracts on animal and human health have been summarized.