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Calcineurin B-like (CBL)-interacting protein kinases (CIPKs) play a central role in Ca 2+ signalling and promote drought tolerance in plants. The CIPK gene family in pigeon pea (Cajanus cajan L.), a major food crop affected by drought, has not previously been characterised. Here, we identified 28 CIPK genes in the pigeon pea genome. Five CcCIPK genes were strongly upregulated in roots upon drought treatment and were selected for further characterisation. Overexpression of CcCIPK13 and CcCIPK14 increased survival rates by two- to three-fold relative to controls after 14 days of drought. Furthermore, the three major flavonoids, genistin, genistein and apigenin, were significantly upregulated in the same transgenic plants. Using CcCIPK14 as bait, we performed a yeast two-hybrid screen and identified six interactors, including CcCBL1. CcCIPK14 exhibited autophosphorylation and phosphorylation of CcCBL1 in vitro. CcCBL1-overexpressed plants displayed higher survival rates upon drought stress as well as higher expression of flavonoid biosynthetic genes and flavonoid content. CcCIPK14-overexpressed plants in which CcCBL1 transcript levels were reduced by RNA interference had lower survival rates, which indicated CcCBL1 in the same pathway as CcCIPK14. Together, our results demonstrate a role for the CcCIPK14-CcCBL1 complex in drought stress tolerance through the regulation of flavonoid biosynthesis in pigeon pea., (© 2021 Society for Experimental Biology and John Wiley & Sons Ltd.)

Our previous study has shown that ampelopsin (AMP), a flavonol mainly found in Ampelopsis grossedentata, could induce cell death in human breast cancer cells via reactive oxygen species generation and endoplasmic reticulum (ER) stress pathway. Here, we examined whether autophagy is activated in AMP-treated breast cancer cells and, if so, sought to find the exact role and underlying molecular profile of autophagy in AMP-induced cell death. Our results showed that AMP treatment activated autophagy in MDA-MB-231 and MCF-7 breast cancer cells, as evidenced by the accumulation of autophagosomes, an increase of microtubule-associated protein 1 light chain 3 beta-2 (LC3B-II) and the conversion of LC3B-I to LC3B-II, the degradation of the selective autophagic target p62/SQSTM1, and the formation of green fluorescent protein (GFP)-LC3 puncta. Blockage of autophagy augmented AMP-induced cell death, suggesting that autophagy has cytoprotective effects. Meanwhile, AMP treatment suppressed Akt-mammalian target of rapamycin (mTOR) pathway as evidenced by dose- and time-dependent decrease of the phosphorylation of Akt, mTOR and ribosomal protein S6 kinase (p70S6K), whereas Akt activator insulin-like growth factor-1 (IGF-1) pretreatment partially restored Akt-mTOR pathway inhibited by AMP and decreased AMP-inuduced autophagy, signifying that AMP activated autophagy via inhibition of the Akt-mTOR pathway. Additionally, blocking ER stress not only reduced autophagy induction, but also alleviated inhibition of the Akt-mTOR pathway induced by AMP, suggesting that activation of ER stress was involved in induction of autophagy and inhibition of the Akt-mTOR pathway. Taken together, these findings indicate that AMP induces protective autophagy in human breast cancer cells through Akt-mTOR pathway via ER stress., (© 2014 The Authors. Cancer Science published by Wiley Publishing Asia Pty Ltd on behalf of Japanese Cancer Association.)

Melatonin improves plant resistance to multiple stresses by participating in the biosynthesis of metabolites. Flavonoids are an important family of plant secondary metabolites and are widely recognized to be involved in resistance; however, the crosstalk between melatonin and flavonoid is largely unknown. We found that the resistance of pigeon pea (Cajanus cajan) to salt, drought, and heat stresses were significantly enhanced by pre-treatment with melatonin. Combined transcriptome and LC-ESI-MS/MS metabolomics analyses showed that melatonin significantly induced the enrichment of flavonoids and mediated the reprogramming of biosynthetic pathway genes. The highest fold-increase in expression in response to melatonin treatment was observed for the CcF3´H family, which encodes an enzyme that catalyses the biosynthesis of luteolin, and the transcription factor CcPCL1 directly bonded to the CcF3´H-5 promoter to enhance its expression. In addition, salt stress also induced the expression of CcPCL1 and CcF3´H-5 , and their overexpression in transgenic plants greatly enhanced salt tolerance by promoting the biosynthesis of luteolin. Overall, our results indicated that pre-treatment of pigeon pea with melatonin promoted luteolin biosynthesis through the CcPCL1 and CcF3´H-5 pathways, resulting in salt tolerance. Our study shows that melatonin enhances plant tolerance to multiple stresses by mediating flavonoid biosynthesis, providing new avenues for studying the crosstalk between melatonin and flavonoids. [ABSTRACT FROM AUTHOR]

The present study was designed to evaluate the chemical extraction, chemical composition, and antioxidant and antibacterial properties of the total flavonoids in Willow Buds (TFW). We investigated the optimal extraction of TFW using response surface methodology (RSM). Chemical compounds were analyzed using Q-Orbitrap LC–MS/MS. The DPPH radical scavenging capacity, hydroxy radical inhibitory ability, and superoxide anion radical inhibitory ability were explored to determine the antioxidant properties of flavonoid extractions. The antibacterial effect was assessed via minimal inhibitory concentration. The results demonstrated that the optimal extraction conditions were an ethanol concentration of 50%, a time of 35 min, and a liquid/material ratio of 70:1 mL/g. Under these conditions, the yield of TFW was 7.57%. Eight flavonoids, a phenolic glycoside, and an alkaloid were enriched in the Willow Buds. The TFW exhibited significant antioxidant activity, with IC50 values of 0.18-0.24 mg/mL and antimicrobial activity against Escherichia coli, Salmonella enterica, Staphylococcus aureus, and Streptococcus pneumoniae. TFW may be explored as potential and natural compounds in food and pharmacological applications. [ABSTRACT FROM AUTHOR]

Artemisia absinthium L. is a highly medicinal plant with a broad range of biomedical applications. A. absinthium callus cultures were established in response to bio-fabricated single NPs (Ag and Cu) or a combination of both NPs (Ag and Cu) in different ratios (1:2, 2:1, 1:3, and 3:1) along with thidiazuron (TDZ) (4 mg/L) to elicit the biomass accumulation, production of non-enzymatic compounds, antioxidative enzymes, and antioxidant activity. Silver and copper nanoparticles (Ag and Cu NPs) were synthesized using the leaves of Moringa oleifera as reducing and capping agent and further characterized through UV-Visible spectroscopy and SEM. The 30 µg/L suspension of Ag and Cu NPs (1:2, 2:1) and 4 mg/L TDZ showed 100% biomass accumulation as compared to control (86%). TDZ in combination with Ag NPs enhanced biomass in the log phases of growth kinetics. The Cu NPs alone enhanced the superoxide dismutase activity (0.56 nM/min/mg FW) and peroxidase activity (0.31 nM/min/mg FW) in callus cultures. However, the combination of Ag and Cu NPs with TDZ induced significant total phenolic (7.31 µg/g DW) and flavonoid contents (9.27 µg/g DW). Furthermore, the antioxidant activity was highest (86%) in the Ag and Cu NPs (3:1) augmented media. The present study provides the first evidence of bio-fabricated single NPs (Ag and Cu) or a combination of both NPs (Ag and Cu) in different ratios (1:2, 2:1, 1:3, and 3:1) along with TDZ (4 mg/L) on the development of callus culture, production of endogenous enzymes, non-enzymatic components, and further antioxidant activity in callus cultures of A. absinthium. [ABSTRACT FROM AUTHOR]

Fig (Ficus carica L.) leaves are produced each year and often disposed, resulting in a waste of resources. Fig waste leaves are rich in flavonoids, which have strong antioxidant activity; however, the variety and chemical structure of antioxidants in fig leaves have not been reported in detail. To take full advantage of fig waste leaves, antioxidant capacity of different extracts (petroleum ether, ethyl acetate, and water) was evaluated by 1, 1-diphenyl-2-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic) acid (ABTS), and ferric-ion-reducing antioxidant power (FRAP) methods. The results showed that flavonoids in ethyl acetate extraction had the highest content (83.92 ± 0.01 mg/g), maximum DPPH scavenging activity (IC50 0.54 mg/mL), highest ABTS scavenging rate (80.28%), and FRAP (3.46 mmol/g). Furthermore, an HPLC-QTOF-MS/MS-DPPH method was developed to identify 11 flavonoids in fig waste leaves. This rapid and efficient method can not only be used for screening the antioxidant components in fig waste leaves, but also can be combined with mass spectrometry to identify the compounds with antioxidant capacity. There are three flavonoids with significant antioxidant capacity, which are 3-O-(rhamnopyranosyl-glucopyranosyl)-7-O-(glucopyranosyl)-quercetin, isoschaftoside, and rutin. The results confirmed that fig waste leaves contain a variety of antioxidant components, which contributed to increase the value of fig waste leaves as antioxidants. [ABSTRACT FROM AUTHOR]

A novel approach for synchronous extraction and enrichment of hydrophilic component and hydrophobic component with CO 2 -based switchable-solvent (SHS) from pigeon pea leaves was developed in the present study. After screening of SHS, N, N-dimethyl-cyclohexylamine (DMCHA)/water system was selected as the properest SHS for the extraction and enrichment process. To optimize this process, we conducted single factor experiments with the Box-Behnken design. The optimal parameters were as follows: solid-liquid ratio R (S/L) 40:1 (mg/mL), ultrasound time 15 min and bubbling CO 2 time 79 min (0.5 mL/s). Under the circumstances, the extraction yields of representative flavonoid vitexin and stilbene cajaninstilbenes acid (CSA) reached 1.80 ± 0.12 mg/g and 9.32 ± 0.08 mg/g, respectively, which were 1.06 and 1.49 folds to those by the traditional methods. And the contents of target compounds vitexin and CSA in the enriched extracts were 2.3% and 12.1%, which increased above 6.76 and 4.58 folds to that in extracts using 65% ethanol-UAE. And the results suggested that the N, N-dimethyl-cyclohexylamine (DMCHA)/water system can be guaranteed for at least 5 cycles with relatively stable extraction yields of vitexin and CSA. Furthermore, a theoretical study using density functional theory was put into effect to explore the properties of SHS and their relationship with the vitexin and CSA. The mechanism study showed that SHS had higher biocompatibility with target compounds due to the H-bonds. The present method was an eco-friendly, promising, and sustainable alternative to extract and enrich simultaneously hydrophilic and hydrophobic phytochemicals from plant materials. Image 1 • This paper developed a novel approach for efficient and recyclable extraction and enrichment of phytochemicals from the disused pigeon pea leaves in one solvent system. • The mechanism study showed that SHS had higher biocompatibility with target compounds due to the H-bonds using the density functional theory. • The switchable solvents have usually been used in the extraction of oil. Moreover, the exploit of SHS considering bioactive compounds from plants material has hardly been reported yet. [ABSTRACT FROM AUTHOR]