Transcriptomics Integrated With Widely Targeted Metabolomics Reveals the Mechanism Underlying Grain Color Formation in Wheat at the Grain-Filling Stage

Colored wheat grains have a unique nutritional value. To elucidate the color formation mechanism in wheat seeds, comprehensive metabolomic and transcriptomic analyses were conducted on purple (Dianmai 20-1), blue (Dianmai 20-8), and white (Dianmai 16) wheat at the grain-filling stage. The results showed that the flavonoid biosynthesis pathway was closely related to grain color formation. Among the 603 metabolites identified in all varieties, there were 98 flavonoids. Forty-six flavonoids were detected in purple and blue wheat, and there were fewer flavonoids in white wheat than in colored wheat. Integrated transcriptomic and metabolomic analyses showed that gene expression modulated the flavonoid composition and content, resulting in different metabolite levels of pelargonidin, cyanidin, and delphinidin, thus affecting the color formation of wheat grains. The present study clarifies the mechanism by which pigmentation develops in wheat grains and provides an empirical reference for colored wheat breeding.

STUDY OF THE FLAVONOID COMPOSITION AND BIOLOGICAL ACTIVITY OF HAWTHORN`S LEAVES CRATAEGUS PONTICA

The results of studies of the content of polyphenolic compounds and their antioxidant activity in the Pontic hawthorn plant Crataegus pontica K.Koch., growing in the mountainous regions of the Tashkent region of the Republic of Uzbekistan are presented. The collection of raw materials took place in the spring at the beginning of October 2019 and at the end of April 2020. The conditions for the isolation of polyphenolic compounds were selected under various conditions. It was shown that the optimal content of polyphenols is extracted with 70% acetone, followed by fractionation of the aqueous residue with ethyl acetate and precipitation with hexane. It was shown that in the plants harvested in spring, the amount of polyphenols was 4.28%, and the collected volume was 2.6%, of the air-dry mass of the raw material. Chromatographic methods (BC and TLC) revealed that the composition of plant leaves collected in spring contains more polyphenols than those collected in autumn. This plant contains compounds belonging to the class of flavonols, phenolic acids and flavan-3-ols. Polyphenols were identified by rutin, quercetin, quercetin-3-O-β-galactoside, catechin, and gallic acid by BC and TLC methods. The antioxidant activity of the sum of polyphenolic compounds was studied in the model of lipid peroxidation (LPO) in rat liver mitochondria. It was found that polyphenols have a protective effect on mitochondria, a reduced damaging effect of Fe2+ / ascorbate and antioxidant activity depends on the concentration of the studied polyphenolic substances. The introduction of rutin into the incubation medium in 5 μM medium inhibits LPO processes by 32.0%, and at 10 μM – by 85.9% and in 20 μM – by 96.8%, compared with the control.

Flavonoid Composition and Pharmacological Properties of Elaeis guineensis Jacq. Leaf Extracts: A Systematic Review

The oil palm tree (Elaeis guineensis Jacq.) originates from West and Central Africa, and it is cultivated in Malaysia for its oil-producing fruits. Malaysia is the world’s second largest palm oil producer and the world’s largest exporter to date. Consequently, the Malaysian oil palm industry constantly generates a huge amount of biomass with the major contributor being the leaves. A large percentage of these leaves remain underutilized, making them a promising source of raw materials that can be converted into value-added products. The present review summarizes and discusses the flavonoid composition, total phenolic and flavonoid content, and the in vitro and in vivo pharmacological properties exhibited by the extracts of the leaves of E. guineensis. The purpose of this systematic review is to highlight the potential of valorizing the leaf extracts of the oil palm tree as pharmaceutical and cosmeceutical agents.

Effects of Irrigation at Different Fractions of Crop Evapotranspiration on Water Productivity and Flavonoid Composition of Cabernet Sauvignon Grapevine

Climate change models predict lower precipitation and higher air temperatures that will negatively affect viticultural regions. Irrigation of vineyards will be crucial for mitigating abiotic stress during the growing season. However, the environmental impact of irrigation requires consideration for ensuring its sustainability in the future. We evaluated the standard irrigation practices on grapevine water use efficiency, berry flavonoid composition, vineyard water footprint, and arbuscular mycorrhizal fungi-grapevine symbiosis in two seasons with contrasting amounts of precipitation. The irrigation treatments consisted of weekly replacement of 25, 50, and 100% of crop evapotranspiration (ETc) during two growing seasons. Irrigation in grapevine vineyards mitigated the water scarcity when precipitation during the dormant season was not sufficient. The results provided field data supporting that despite the low rainfall recorded in one of the seasons, increasing the amount of irrigation was not advised, and replacing 50% ETc was sufficient. In this treatment, berry composition was improved with increased contents of total soluble solids, anthocyanins, and flavonols, and a stable flavonoid profile without an economic decrease in yield. In addition, with 50% ETc, the mycorrhizal symbiosis was not compromised and water resources were not highly impacted. Altogether, our results provide fundamental knowledge for viticulturists to design an appropriate irrigation schedule under the future warming scenarios with minimal environmental impact in semi-arid regions facing warming trends.

Phenolic Profiles of Ten Australian Faba Bean Varieties

Although Australia is the largest exporter of faba bean globally, there is limited information available on the levels of bioactive compounds found in current commercial faba bean varieties grown in this country. This study profiled the phenolic acid and flavonoid composition of 10 Australian faba bean varieties, grown at two different locations. Phenolic profiling by HPLC-DAD revealed the most abundant flavonoid to be catechin, followed by rutin. For the phenolic acids, syringic acid was found in high concentrations (72.4–122.5 mg/kg), while protocatechuic, vanillic, p-hydroxybenzoic, chlorogenic, p-coumaric, and trans-ferulic acid were all found in low concentrations. The content of most individual phenolics varied significantly with the variety, while some effect of the growing location was also observed. This information could be used by food processors and plant breeders to maximise the potential health benefits of Australian-grown faba bean.

Chemical composition and vasodilator activity of different Alpinia zerumbet leave extracts, a potential source of bioactive flavonoids

A polyphenol-rich extract with an expressive vasodilator effect was obtained from fresh leaves of Alpinia zerumbet (AZ), a medicinal plant. The vasodilator effects of AZ obtained from different extraction conditions were studied in perfused mesenteric vascular bed, and total polyphenol content (TPC) was determined for all samples. Chemical composition of AZ was analyzed by UHPLC/ESI-QTOF-MS, and a list of putative compounds was obtained by a molecular network. Briefly, results obtained indicate a 50% hydroethanolic extract from fresh leaves (AZE4) as the best extraction condition, presenting the greatest vasodilator effect (ED 50 = 7.1 µg ± 1.73) and TPC (16.30 mg GAE/g ± 0.44). Flavonoids were detected as main constituents and alpinetin, kaempferol-3-O-glucuronide, (-)- epicatechin and pinocembrin were identified as major compounds. The last effective extraction condition was 50% hydroethanolic extract from dried leaves without heating, which showed the smallest vasodilator response (ED 50 = 29.1 µg ± 4.3) and TPC (6.35 mg GAE/g ± 0.08), reinforcing the use of fresh leaves and heating step to improve extracts performance. The vasodilator effect and the main flavonoid composition of AZE4 provide experimental support for the indication of this extract as a potential source of bioactive flavonoids for the treatment of cardiovascular diseases.

Flavonoids of the Caryophyllaceae

The plant family Caryophyllaceae, commonly known as the pink family, is divided into 3 subfamilies and contains over 80 genera with more than 2600 species that are widely distributed in temperate climate zones. Plants belonging to this family produce a variety of secondary metabolites important in an ecological context; however, some of these metabolites also show health-promoting activities. The most important classes of phytochemicals include saponins, phytoecdysteroids, other sterols, flavonoids, lignans, other polyphenols, essential oils, and N-containing compounds such as vitamins, alkaloids or cyclopeptides. Flavonoids are polyphenolic compounds that remain one of the most extensively studied constituents of the Caryophyllaceae family. Numerous structurally diverse aglycones, including flavones, flavonols, flavonones (dihydroflavones), flavonols, isoflavones, and their O- or C-glycosides, exhibit multiple interesting biological and pharmacological activities, such as antioxidant, anti-inflammatory, anti-oedemic, antimicrobial, and immunomodulatory effects. Thus, this review analysed the flavonoid composition of 26 different genera and more than 120 species of Caryophyllaceae for the first time.

Integrative Transcriptomic, and Proteomic Analysis of Flavonoid Biosynthesis During Fruit Maturation In Chinese Raspberry “Rubus Chingii Hu”

Rubus chingii, is a red-fruited species of Rubus native to China, which is a popular and nutritious fruit in China. However, change in flavonoid composition and content during fruit maturation is poorly understood. This study examined flavonoids and the genes/proteins during four fruit ripening phases using LC-MS/MS. As a result, six major kinds of anthocyanins were first identified in R. chingii, which primarily consisted of flavanol-anthocyanins, are new to Rubus. Apart from anthocyanins, concentrations of fruit flavonoids were much higher than most berries including raspberries, and it is this that contributes to their high phenolic concentrations and antioxidant capabilities. In contrast to other known raspberries, R. chingii had a decline in flavonoids during fruit maturation, which was due to down-regulation of genes/proteins involved in phenylpropanoid and flavonoid biosynthesis. Surprisingly, anthocyanin continuously decreased during fruit coloration. This suggests that anthocyanins are not responsible for the fruit’s reddish coloration. The biosynthesis of these flavanol-anthocyanins consumed two flavonoid units both produced through the same upstream pathway. Their presence indicates a reduction in the potential biosynthesis of anthocyanin production. Also, the constantly low expression of RcANS gene down-regulated overall anthocyanin biosynthesis. The lack of RcF3’5’H gene/protein hindered the production of delphinidin glycosides. Flavonoids primarily comprising of quercetin/kaempferol-glycosides were predominately located at fruit epidermal-hair and placentae. The profile and biosynthesis of R. chingii flavonoids are unique to Rubus. It could be used to broaden the genetic base of raspberry cultivars and to improve their fruit quality.