Major Flavonoid Research Articles

Optimization of pulsed mode sonication and in silico molecular docking study for antioxidant properties of mandarin (Citrus reticulata Blanco) peels

AbstractThe present study is aimed to investigate the extractability of bioactive compounds from mandarin (Citrus reticulata Blanco) peel using a pulsed mode of ultrasonic treatment. Box–Behnken experimental design associated with response surface methodology (RSM) was used for the process optimization. Ultrasound amplitude (60%–80%), time (5–15 min), and duty cycle (.30–.90) were the independent variables investigated to maximize the yield of total phenolic content (TPC), total saponin content (TSC), total flavonoid content (TFC), total condensed tannin (TCT), and antioxidant activity (DPPH and FRAP methods). The optimum predicted values of the TPC (27.23 g GAE/100 g dry weight [DW]), TFC (5.64 g QE/100 g DW), TCT (3.17 mg CE/g DW), TSC (42.36 mg EE/g DW), DPPH (4.01 mg GAE/g DW) and FRAP (13.71 mg TE/g DW) were obtained at conditions: 11.19 min of sonication at a duty cycle of .30 and 77.70% amplitude. Furthermore, in silico investigations of anti‐oxidant properties of major flavonoids were done using molecular docking. The analysis showed a better binding affinity of narirutin for Cytochrome P450 and myeloperoxidase, while hesperidin showed a better binding affinity with lipoxygenase. The results obtained from the study showed better phenolic extraction and high antioxidant activity using pulsed mode sonication. The high binding scores of hesperidin and narirutin for all three key enzymes, as obtained by molecular docking, have shown their therapeutic potential in the development of antioxidant drugs.Practical ApplicationsA practical insight of the present research suggests the applicability of optimized pulsed mode extraction conditions for industrial processing of Citrus reticulata Blanco peel, a green technology useful in terms of its biomedical application. The optimized extraction conditions will give a higher yield with reduced time and with less use of extraction solvents. The in silico analysis provides scope for predictive modeling of novel antioxidative drug development using major flavonoid compounds of Citrus reticulata Blanco peel.

Evaluation of the Effect of Different Co-Solvent Mixtures on the Supercritical CO2 Extraction of the Phenolic Compounds Present in Moringa oleifera Lam. Leaves

Supercritical fluid extraction (SFE), using CO2, is a novel, sustainable and very efficient technique for the recovery of highly apolar compounds. However, the recovery of phenolic compounds requires the use of different co-solvent combinations such as water and ethanol to enhance the recovery of these compounds through the optimization of a number of variables. In this sense, the effect of pressure (100, 150 and 200 bar), temperature (50, 65 and 80 °C), extraction time (30, 60, 90, 120, 150 and 180 min) and the effect of the different percentages of ethanol and water as co-solvents on the composition and phenolic content of moringa leaf extracts were evaluated. Six major flavonoids were identified by ultra-high-performance liquid chromatography coupled to a quadrupole-time-of-flight mass spectrometer (UHPLC-Q-ToF-MS). Pressure and temperature had a significant effect on the phenolic composition of the extracts, as well as on their concentrations. The highest concentration of total flavonoids compounds (TFCs) was obtained by using a mixture of CO2 and water of 50:50 (v/v) at 100 bar, at 65 °C after a 120 min extraction time that produced a concentration of 11.66 mg ± 0.02 mg TFC g−1 sample, which corresponds to 89.0% of the total flavonoids of the sample, obtained by exhaustive extraction.

The flavonoid profiles in the pulp of different pomelo (Citrus grandis L. Osbeck) and grapefruit (Citrus paradisi Mcfad) cultivars and their in vitro bioactivity.

Previous results indicated that the flavonoid profiles might have varietal differences in pomelo, but detailed information is unknown. We previously isolated 4 new flavonoids, cigranoside C, D, E, F, in Citrus grandis Shatianyu pulp. However, their distribution in different pomelo cultivars remains to be explored. Therefore, the flavonoid profiles and in vitro bioactivity of the pulp from 5 pomelo and 1 grapefruit cultivars commonly consumed in China were investigated. Fourteen flavonoids were identified, cigranoside C, D, E were detected in these pomelo and grapefruit. Naringin and cigranoside C were the major flavonoids in grapefruit, Guanximiyu-W, Guanximiyu-R and Liangpingyu, while melitidin and rhoifolin was the predominant flavonoid in Shatianyu and Yuhuanyu, respectively. Pomelo and grapefruit showed strong antioxidant activity, and were potent inhibitors of pancreatic lipase with IC50 values of 11.4-72.6mg fruit/mL except Shatianyu. Thus, pomelo and grapefruit are natural antioxidants and possess anti-obesity potential.

Inter-Varietal Variation in Phenolic Profile, Sugar Contents, Antioxidant, Anti-Proliferative and Antibacterial Activities of Selected Brassica Species

The main objective of this research work was to evaluate the variation in nutritional profile, antioxidant, anti-proliferative and antibacterial activities of selected species of Brassica. Five locally grown Brassica species (cauliflower, broccoli, red cabbage, white cabbage and Chinese cabbage) were collected from Ayub Agriculture Research Institute (AARI), Faisalabad, Pakistan. Polyphenolic rich extracts of these Brassicaceae species were prepared by Soxhlet extraction technique using ethanol. Phenolic acids, flavonoids and sugar contents of the investigated species were determined and quantified by RP-HPLC. Antioxidant activity was carried out by measurement of total phenolic contents (TPC), total flavonoid contents (TFC), reducing potential and 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity. Anti-proliferative activity of all the extracts was determined by MTT assay on lung cancer cell line A549. Antibacterial activity was tested against the two bacterial strains, i.e., Bacillus cereus (B. cereus) and Escherichia coli (E. coli). HPLC analysis revealed the presence of gallic acid, p-coumaric acid, chlorogenic acid and benzoic acid as the major phenolic acids, whereas catechine was the major flavonoid in most of the extracts. The TPC ranged from 9.7 to 32.8 mg/g of dry plant material, measured GAE and TFC ranged from 7.7 to 23.7 mg/g of dry plant material, measured as CE. Higher TPC and TFC were found in red cabbage extract followed by cauliflower, broccoli, white cabbage and Chinese cabbage. Red cabbage extract also showed higher DPPH radical scavenging activity (IC50 = 2.3 µg/mL) followed by cauliflower, broccoli, white cabbage and Chinese cabbage. Maltodextrose was the major sugar followed by fructose in all species of Brassica. Promising anti-proliferative and antibacterial activities were also recorded by the selected Brassica extracts.

Icariin ameliorates memory deficits through regulating brain insulin signaling and glucose transporters in 3×Tg-AD mice.

Icariin, a major prenylated flavonoid found in Epimedium spp., is a bioactive constituent of Herba Epimedii and has been shown to exert neuroprotective effects in experimental models of Alzheimer's disease. In this study, we investigated the neuroprotective mechanism of icariin in an APP/PS1/Tau triple-transgenic mouse model of Alzheimer's disease. We performed behavioral tests, pathological examination, and western blot assay, and found that memory deficits of the model mice were obviously improved, neuronal and synaptic damage in the cerebral cortex was substantially mitigated, and amyloid-β accumulation and tau hyperphosphorylation were considerably reduced after 5 months of intragastric administration of icariin at a dose of 60 mg/kg body weight per day. Furthermore, deficits of proteins in the insulin signaling pathway and their phosphorylation levels were significantly reversed, including the insulin receptor, insulin receptor substrate 1, phosphatidylinositol-3-kinase, protein kinase B, and glycogen synthase kinase 3β, and the levels of glucose transporter 1 and 3 were markedly increased. These findings suggest that icariin can improve learning and memory impairments in the mouse model of Alzheimer's disease by regulating brain insulin signaling and glucose transporters, which lays the foundation for potential clinical application of icariin in the prevention and treatment of Alzheimer's disease.

Korean naked waxy barley (saechalssal) extract reduces blood glucose in diabetic mice by modulating the PI3K-Akt-GSK3β pathway.

Saechalssal barley is Korea's representative naked waxy barley. This study investigated the anti-diabetic effect of the extract derived from saechalssal and its mechanism. The prethanol extract of saechalssal (SPE) showed greater α-glucosidase inhibitory activity in vitro and a more significant lowering of the postprandial blood glucose levels in normal mice compared to its water extract (SWE). When mice with type 2 diabetes (T2DM) induced by a high-fat diet and streptozotocin were fed SPE (200mg/kg/day) for six weeks, the fasting blood glucose and serum free fatty acid levels were significantly lower than those of the control group. SPE significantly elevated the hepatic glycogen accumulation with increasing glycogen synthesis-related gene (GYS2 and UGP2) levels compared to the control group. SPE stimulated the expression of the hepatic glycolysis-related genes (GK, PFK1, and PK) and suppressed the gluconeogenesis-related genes (G6Pase, FBP1, and PEPCK). SPE up-regulated the phosphorylation of phosphatidylinositol 3-kinase (PI3K) and protein kinase B (Akt), whereas it down-regulated the phosphorylation of glycogen synthase kinase 3 beta (GSK3β) compared to the control. The major flavonoids of SPE were naringin, prunin, and catechin, while its phenolic acids were ferulic acid and vanillic acid. These phytochemical compounds may contribute to the anti-hyperglycemic effects of SPE in diabetes. Overall, these results suggest that SPE has potential anti-diabetic activity through the regulating the PI3K/Akt/GSK3β pathway.

Optimising the Polyphenolic Content and Antioxidant Activity of Green Rooibos (Aspalathus linearis) Using Beta-Cyclodextrin Assisted Extraction.

Antioxidant activity associated with green rooibos infusions is attributed to the activity of polyphenols, particularly aspalathin and nothofagin. This study aimed to optimise β-cyclodextrin (β-CD)-assisted extraction of crude green rooibos (CGRE) via total polyphenolic content (TPC) and antioxidant activity assays. Response surface methodology (RSM) permitted optimisation of β-CD concentration (0–15 mM), temperature (40–90 °C) and time (15–60 min). Optimal extraction conditions were: 15 mM β-CD: 40 °C: 60 min with a desirability of 0.985 yielding TPC of 398.25 mg GAE·g−1, metal chelation (MTC) of 93%, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging of 1689.7 µmol TE·g−1, ferric reducing antioxidant power (FRAP) of 2097.53 µmol AAE·g−1 and oxygen radical absorbance capacity (ORAC) of 11,162.82 TE·g−1. Aspalathin, hyperoside and orientin were the major flavonoids, with quercetin, luteolin and chrysoeriol detected in trace quantities. Differences (p < 0.05) between aqueous and β-CD assisted CGRE was only observed for aspalathin reporting the highest content of 172.25 mg·g−1 of dry matter for extracts produced at optimal extraction conditions. Positive, strong correlations between TPC and antioxidant assays were observed and exhibited regression coefficient (R2) between 0.929–0.978 at p < 0.001. These results demonstrated the capacity of β-CD in increasing polyphenol content of green rooibos.

Valorisation of the industrial waste of Chukrasia tabularis A.Juss.: Characterization of the leaves phenolic constituents and antidiabetic-like effects

Chukrasia tabularis A.Juss. is a canopy tree widely distributed in Asia and commonly used for construction-grade timber. While the residues resulting from the timber exploration constitute the major source of waste, other parts of the plant remain underutilized. Therefore, aiming the valorisation of a major residue resulting from C. tabularis wood industry, the leaves were here investigated on their potential content in bioactive constituents, but also on their capacity to modulate mediators and enzymes engaged in metabolic disorders, particularly those involved on the development and progression of diabetes. HPLC–DAD–ESI/MSn and UPLC-ESI-QTOF-MS2 characterization of a methanol extract obtained from the leaves, allowed the identification of 25 phenolic constituents, quercetin-3-O-rhamnoside being identified as the main bioactive. The leaf extract and the major flavonoid (quercetin-3-O-rhamnoside) were investigated on their impact towards a series of targets involved in the physiopathology of diabetes. The extract displayed significant scavenging properties against nitric oxide and superoxide radicals, inhibiting also lipid peroxidation and aldose reductase activity. While no noteworthy effects were noted on pancreatic lipase and α-amylase activity, the extract strongly inhibited α-glucosidase (IC50 = 21.14 µg/mL) and proved to be ca. 5 times more effective than the benchmark drug, acarbose. Moreover, the leaf extract significantly inhibited also 5-lipoxygenase (5-LOX) (IC50 = 13.12 µg/mL). Kinetic studies on α-glucosidase and 5-LOX activity disclosed a mixed type inhibition. Furthermore, C. tabularis extract reduced LPS-induced overproduction of NO, L-citrulline and IL-6 in activated RAW 264.7 macrophages. When individually assayed, quercetin-3-O-rhamnoside significantly contributed to the antiradical properties and inhibitory effects of the extract upon the enzymatic targets, but other phenolic bioactives appear also to underlie the recorded anti-inflammatory effects. Taken together, our results demonstrate that the leaves of C. tabularis are rich in phenolic constituents with a great potential to improve metabolic disorders. The evidenced bioactivity of this industrial product might feed R&D programs for the development of new drugs that might simultaneously improve glycaemic, oxidative and inflammatory benchmarks in diabetic patients.

Effects of Fagonia indica on Letrozole-Induced Polycystic Ovarian Syndrome (PCOS) in Young Adult Female Rats.

Polycystic ovarian syndrome is a multidisciplinary endocrinopathy of reproductive-aged women that provokes insulin resistance, hyperandrogenism, cardiovascular problems, obesity, and menstrual complications. The present study was designed to investigate the effectiveness of ethanolic extract of Fagonia indica in letrozole-induced PCOS young adult female rats. HPLC was carried out to find the phenolic and flavonoid content of the ethanolic extract of Fagonia indica. Twenty-five female rats were taken and initially divided into two groups: group I (control group) and group II (PCOS group). PCOS was induced by letrozole given orally by gavage. Body weight was recorded weekly and vaginal cytology was analyzed daily. After induction of disease, the PCOS group is further divided into four groups (n = 5): group II (positive control with PCOS), group III (metformin 20 mg/kg treated group), group IV (ethanolic extract of Fagonia indica 500 mg/kg treated group), and group V (metformin plus Fagonia extract). At the end of experimental period, the blood sample of each rat was collected and serum was separated by centrifugation. Afterwards hormonal analysis, lipid profile and liver functioning tests were performed. Ovaries were removed and preserved for histopathological findings while the liver of each rat was stored for the determination of antioxidant potential assessment. Fagonia indica was found to possess quercetin as one of the major flavonoid phytoconstituents. The plant extract exhibited its beneficial effects by restoring hormonal balance, lipid profile, and liver functioning markers. Treatment with F. indica reduced body weight, resolved ovarian cysts, and showed positive effects on follicular growth. Treatment with plant also increased the levels of antioxidant enzymes. This study validates the potential of Fagonia indica for the amelioration of metabolic, as well as, hormonal disturbances that occurred in PCOS.

The First Optimization Process from Cultivation to Flavonoid-Rich Extract from Moringa oleifera Lam. Leaves in Brazil.

Flavonoids are significant antioxidant and anti-inflammatory agents and have multiple potential health applications. Moringa oleifera is globally recognized for its nutritional and pharmacological properties, correlated to the high flavonoid content in its leaves. However, the bioactive compounds found in plants may vary according to the cultivation, origin, season, and extraction process used, making it difficult to extract reliable raw material. Hence, this study aimed to standardize the best cultivation and harvest season in Brazil and the best extraction process conditions to obtain a flavonoid-rich extract from M. oleifera as a final product. Firstly, ultrasound-assisted extraction (UAE) was optimized to reach the highest flavonoid content by three-level factorial planning and response surface methodology (RSM). The optimal cultivation condition was mineral soil fertilizer in the drought season, and the optimized extraction was with 80% ethanol and 13.4 min of extraction time. The flavonoid-rich extract was safe and significantly decreased reactive oxygen species (ROS) and nitric oxide (NO) in LPS-treated RAW 264.7 cells. Lastly, the major flavonoids characterized by HPLC-ESI-QTRAP-MS/MS were compounds derived from apigenin, quercetin, and kaempferol glycosides. The results confirmed that it was possible to standardize the flavonoid-rich extract leading to a standardized and reliable raw material extracted from M. oleifera leaves.

Flavonoid Composition and Antioxidant Efficacy of Citrus Peels: An Integrated &lt;em&gt;in vitro&lt;/em&gt; and &lt;em&gt;in silico &lt;/em&gt;Approach toward Potential Neuroprotective Agents

The current study explored the therapeutic significance of different standardized citrus peel extracts as potential neuroprotective agents using integrated in vitro and in silico approaches. Hydroethanolic extract of five industrially important citrus fruit peels were subjected to HPLC-based quantification of estimating major flavonoids of nutraceutical importance. Pharmacological activities like antioxidant and anti-inflammatory activities of the extracts were determined by in vitro assays. Further, The identified bioactive metabolites were subjected to the Prediction of Activity Spectra for Substances program to get a prediction of their biological activity spectrum. Amongst various solvent combinations, 80% ethanol provided maximum (≥ 20% w/w) extract yield. Mandarin peels of Citrus reticulata showed the highest amount of polyphenolics ( Citrus reticulata Blanco; 42.24 ± 0.57 mg gallic acid equivalent/g) and flavonoids ( Citrus reticulata c.v .;13.08 ± 0.17 mg quercetin equivalent/g) content. The most abundant flavonoid compound present in all the citrus peel was hesperidin, except Citrus reticulata Blanco and Citrus grandis , which showed a considerably high amount of nobiletin and naringin, respectively. Citrus reticulate c.v. peel extract showed potent antioxidant [IC 50 = 118.82 ± 1.97 µg/mL in 2,2-diphenyl-1-picrylhydrazyl assay and IC 50 = 138.12 ± 2.67 µg/mL in 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid assays)], anti-inflammatory (IC 50 = 50.61 ± 6.79 µg/mL), and acetylcholinesterase inhibitory ((IC 50 = 130.61 ± 2.04µg/mL) activities compared to the other extracts. In silico assessment revealed a high (Pa &gt; 0.7) activity score for free radical scavenging, lipid peroxidase inhibitory, membrane integrity agonistic, anti-inflammatory, antioxidant, and several other important biological activities of the identified flavonoids in the extracts, thus supported neuroprotective potential. Citrus flavonoids naringin, rutin, and tangeretin showed high activity scores for anti-inflammatory activity strengthening the results of in vitro assay. These potentials of citrus peels could be utilized in the development of functional foods and nutraceuticals for neurodegenerative conditions. Furthermore, such a practice will help citrus agro-industrial waste valorisation.

Hesperetin modulation of oxidative stress and inflammatory mediators in LPS‐Activated BV‐2 Microglial Cells

Neurodegeneration affects millions of Americans each year, occurring in later periods of life, where its onset is induced by neuroinflammation and oxidative stress. Flavonoids are known to protect against damages caused by reactive oxygen species (ROS) and reactive nitrogen species (RNS). This study evaluated the effect of hesperetin (HST), a major flavonoid found in oranges and mandarins, on LPS‐activated BV‐2 microglial cells. The obtained results of RT‐PCR showed that HST down‐regulated the mRNA expression of PD‐L1 in more than 50% of the LPS‐activated cells. In addition, HST induced the mRNA expression of Nrf2, which is involved in the transcription of several antioxidant genes. Moreover, the data from the oxidative stress PCR arrays showed that after 24 h, the concentration of 100 µM of HPT modulated numerous genes that regulate oxidative stress and inflammatory processes. HST down‐regulated the mRNA expression of ERCC6, ACTB, SQSTM11, NOS2, and NCF1 and up‐regulated the expression of HMOX1, which participate not only in excessive oxidative stress processes, by also in exacerbated inflammatory states. Both CAT and SOD enzymatic assays showed that treatment with HSP and LPS alone had no effect on CAT expression, but when cells were treated with the combination of HST and LPS, there was a reduction in these expressions enzymes. The quantitative glutathione assays demonstrated that only the combination treatment of HST and LPS reduced the expression of glutathione after a 24‐h treatment period. In conclusion, these data show that hesperetin modulates several genes associated with oxidative stress and neuroinflammation and may potentially slow the progression of neurodegeneration.

A Comprehensive Insight into the Phytochemical, Pharmacological Potential, and Traditional Medicinal Uses of Albizia lebbeck (L.) Benth.

Background Albizialebbeck is a deciduous tree having tremendous medicinal utilities, for example, respiratory, skin, gastrointestinal, oral disorders, eye, urinary, genital, anorectal, inflammatory, and neurological disorders, and venereal diseases. Several studies have been undertaken on the medicinal and traditional values of A. lebbeck. Objective The detailed information about its medicinal uses and pharmacological implications is highly scattered and distributed in different data sources. Hence, the study was conducted to supply an inclusive review of its ethnomedicinal uses, phytochemicals, and the available pharmacological attributes supporting its efficiency in traditional medicine. Method Literature surveys were conducted on this medicinal plant via search engines like Google Scholar, PubMed, and Science Direct, and obtained information up to December 2020 has been assessed and analyzed for this study. Results Systematic investigation revealed that A. lebbeck consists of various phytochemicals, including major alkaloids, flavonoids, saponins, and terpenoids. Its crude extract, fraction, and bioactive compounds exhibited potent adulticidal, antiallergic, anticancer, anticonvulsant, antidiabetic, antidiarrheal, anti-inflammatory, antimicrobial, antinociceptive, antioxidant, antiparasitic, antipyretic, antivenom, estrogenic, neuroprotective, nootropic, ovicidal, and wound healing activities. Conclusions This study proposes that A. lebbeck remains a rich source of phytochemicals with various biological activities which possess outstanding therapeutic benefits to humanity across the world. However, studies are required to estimate the potential side effects. Moreover, mechanistic physiognomies of the isolated compounds with known bioactivities are quite limited; thus, forthcoming research needs to focus on the mechanisms of these active phytochemicals to facilitate their potential enrolling for drug discovery.

FtUGT79A15 is responsible for rutinosylation in flavonoid diglycoside biosynthesis in Fagopyrum tataricum

Tartary buckwheat shows health benefits with its high antioxidant activity and abundant flavonoid content. However, glycosylated flavonoid accumulation patterns and their molecular basis remain unidentified in Tartary buckwheat. Here, our metabolomics analysis revealed that F3′H branching was the major flavonoid metabolic flux in Tartary buckwheat. Interestingly, metabolome results also showed that the most abundant flavonoids were mainly in the glycosylated form, including flavonoid glycosides and flavonoid diglycosides in Tartary buckwheat. However, the flavonoid glycosides glycosyltransferase (GGT) gene catalyzing the second glycosylation step of flavonoid diglycoside has not been discovered yet in Tartary buckwheat. Thus, we explored GGT genes in the transcriptome-metabolome correlation network and confirmed that FtUGT79A15 showed the rhamnosyltransferase activity to catalyze quercetin 3-O-glucoside to rutin invitro and inplanta. Overall, FtUGT79A15 was identified to involve in the flavonoid diglycoside biosynthesis pathway in Tartary buckwheat.

Isoliquiritin Ameliorates Cisplatin-Induced Renal Proximal Tubular Cell Injury by Antagonizing Apoptosis, Oxidative Stress and Inflammation.

Acute kidney injury (AKI) is a clinical syndrome characterized by morbidity, mortality, and cost. Cis-diamminedichloroplatinum (cisplatin) is a chemotherapeutic agent used to treat solid tumors and hematological malignancies, but its side effects, especially nephrotoxicity, limit its clinical application. Isoliquiritin (ISL), one of the major flavonoid glycoside compounds in licorice, has been reported to have anti-apoptotic, antioxidant, and anti-inflammatory activities. However, the effect and mechanism of ISL on cisplatin-induced renal proximal tubular cell injury remain unknown. In this study, mouse proximal tubular cells (mPTCs) and human proximal tubule epithelial cells (HK2) were administered increasing concentrations of ISL from 7.8125 to 250 μM. Moreover, mPTC and HK2 cells were pretreated with ISL for 6–8 h, followed by stimulation with cisplatin for 24 h. CCK-8 assay was performed to evaluate the cell viability. Apoptosis and reactive oxygen species (ROS) of cells were measured by using flow cytometer and western blotting. Our results showed that ISL had no obvious effect on cell viability. ISL decreased cisplatin-induced cell injury in a dose-dependent manner. ISL also protected against cisplatin-induced cell apoptosis. Meanwhile, the enhanced protein levels of Bax, cleaved caspase-3/caspase-3 ratio, levels of Pp-65/p-65, levels of IL-6, and the production of ROS induced by cisplatin were significantly attenuated by ISL treatment. Moreover, ISL markedly increased the protein levels of Bcl-2 and SOD2, which were reduced by cisplatin stimulation. These results showed that ISL ameliorated cisplatin-induced renal proximal tubular cell injury by antagonizing apoptosis, oxidative stress and inflammation.

Rutin-stevioside and related conjugates for potential control of grapevine trunk diseases

Flavonoids and phenolic acids play roles in grapevine defence against pathogens causing grapevine trunk diseases (GTDs). Rutin is a major flavonoid in vegetative organs of the grapevines, and this compound, unlike other flavonoids, is non-toxic and non-oxidizable. Rutin was assayed in vitro and in vivo against two Botryosphaeriaceae taxa. The limited bioavailability of this compound was circumvented by conjugation with stevioside, a glycoside obtained from Stevia rebaudiana. Clear synergistic effects were observed for the stevioside-rutin adduct, resulting in EC50 and EC90 values of 306.0 and 714.9 μg·mL-1 against Neofusicoccum parvum and 241.6 and 457.8 μg·mL-1 against Dothiorella viticola. In greenhouse experiments, moderate inhibition of N. parvum growth and complete inhibition of D. viticola were observed. These inhibitory effects were greater than those of ferulic acid, which has been considered the most effective phenolic acid against GTDs. Conjugation with stevioside provided solubility enhancement of rutin, paving the way to the design of glycopesticides based on rutin-rich plant extracts as promising antifungals against GTDs.

Antiosteoporosis Effects, Pharmacokinetics, and Drug Delivery Systems of Icaritin: Advances and Prospects.

Osteoporosis is a systemic skeletal disorder affecting over 200 million people worldwide and contributes dramatically to global healthcare costs. Available anti-osteoporotic drug treatments including hormone replacement therapy, anabolic agents, and bisphosphonates often cause adverse events which limit their long-term use. Therefore, the application of natural products has been proposed as an alternative therapy strategy. Icaritin (ICT) is not only an enzyme-hydrolyzed product of icariin but also an intestinal metabolite of eight major flavonoids of the traditional Chinese medicinal plant Epimedium with extensive pharmacological activities, such as strengthening the kidney and reinforcing the bone. ICT displays several therapeutic effects, including osteoporosis prevention, neuroprotection, antitumor, cardiovascular protection, anti-inflammation, and immune-protective effect. ICT inhibits bone resorption activity of osteoclasts and stimulates osteogenic differentiation and maturation of bone marrow stromal progenitor cells and osteoblasts. As for the mechanisms of effect, ICT regulates relative activities of two transcription factors Runx2 and PPARγ, determines the differentiation of MSCs into osteoblasts, increases mRNA expression of OPG, and inhibits mRNA expression of RANKL. Poor water solubility, high lipophilicity, and unfavorable pharmacokinetic properties of ICT restrict its anti-osteoporotic effects, and novel drug delivery systems are explored to overcome intrinsic limitations of ICT. The paper focuses on osteogenic effects and mechanisms, pharmacokinetics and delivery systems of ICT, and highlights bone-targeting strategies to concentrate ICT on the ideal specific site of bone. ICT is a promising potential novel therapeutic agent for osteoporosis.

Antifibrotic activities of Scutellariae Radix extracts and flavonoids: Comparative proteomics reveals distinct and shared mechanisms

BackgroundScutellariae Radix (SR), the root of Scutellaria baicalensis Georgi, and SR flavonoids have antifibrotic activities. It remains obscure, however, amongst SR aqueous extract (SRA), SR methanolic extract (SRM) and five major SR flavonoids (baicalein, baicalin, wogonoside, wogonin and oroxyloside), which ones are the most promising antifibrotics and what their mechanisms are. PurposeTo compare the antifibrotic activities of SR extracts and flavonoids, and the proteomic signatures of selected SR extract and flavonoid, versus IN1130 phosphate, an antifibrotic positive control (abbreviated as IN1130), in TGF-β1-induced in vitro model of fibrosis in NRK-49F renal fibroblasts. MethodsIsobaric labelling-based mass spectrometry was used for proteomic studies. Differentially expressed proteins were further analyzed using Gene Ontology annotation enrichment, protein-protein interaction network analysis and pathway analysis. Selected proteins of interest were validated by enzyme-linked immunosorbent assay (ELISA). ResultsBaicalein was the SR flavonoid with the best efficacy-toxicity ratio. SRM contained 8-fold more flavonoids and was more potently antifibrotic than SRA. Proteomic analysis of cells treated by TGF-β1, with or without baicalein (40 and 80 μM), SRM (40 and 80 μg/ml) and IN1130 (1 μM) suggested that baicalein, SRM and IN1130 all repressed TGF-β1-induced ribosomal proteins in cell lysates, while baicalein and SRM, but not IN1130, regulated the intracellular lysosome pathway; secretomic analysis suggested that 40 and 80 μg/ml SRM and 80 μM baicalein, but not IN1130 and 40 μM baicalein increased ribosomal proteins in conditioned media, whereas only baicalein regulated the lysosome pathway. ELISA verified secretomic findings that baicalein, SRM and IN1130 repressed TGF-β1-induced PAI-1 (Serpine1), Plod2, Ctgf (Ccn2), Ccl2 and Ccl7; baicalein and IN1130, but not SRM, reversed TGF-β1-induced Cyr61 (Ccn1) and Tsku; only baicalein reversed TGF-β1 repression of Mmp3; only IN1130 reversed TGF-β1-repressed Nov (Ccn3). ELISA validated cell-lysate proteomic findings that baicalein, SRM and IN1130 all reversed TGF-β1-induced Enpp1; only IN1130 reversed TGF-β1-induced Impdh2 and Sqstm1 and TGF-β1-repressed Aldh3a1. Baicalein and SRM induced Ccdc80, while only baicalein induced Tfrc. ConclusionBaicalein, SRM and IN1130 repress TGF-β1-induced fibrogenesis in renal fibroblasts by regulating overlapping protein targets and biological pathways. Our findings offer a comprehensive view of shared, drug- and dose-specific pharmacological and toxicological mechanisms and provide a valuable resource for further research and development of more efficacious and safer antifibrotics.

Dihydrohomoplantagin and Homoplantaginin, Major Flavonoid Glycosides from Salvia plebeia R. Br. Inhibit oxLDL-Induced Endothelial Cell Injury and Restrict Atherosclerosis via Activating Nrf2 Anti-Oxidation Signal Pathway.

Oxidized low-density lipoprotein (oxLDL)-induced endothelium injury promotes the development of atherosclerosis. It has been reported that homoplantaginin, a flavonoid glycoside from the traditional Chinese medicine Salvia plebeia R. Br., protected vascular endothelial cells by inhibiting inflammation. However, it is undetermined whether homoplantaginin affects atherosclerosis. In this study, we evaluated the effect of homoplantaginin and its derivative dihydrohomoplantagin on oxLDL-induced endothelial cell injury and atherosclerosis in apoE-/- mice. Our results showedthat both dihydrohomoplantagin and homoplantaginin inhibited apoptosis and the increased level of ICAM-1 and VCAM-1 in oxLDL-stimulated HUVECs and the plaque endothelium of apoE-/- mice. Additionally, both of them restricted atherosclerosis development of apoE-/- mice. Mechanistic studies showed that oxLDL-induced the increase in ROS production, phosphorylation of ERK and nuclear translocation of NF-κB in HUVECs was significantly inhibited by the compounds. Meanwhile, these two compounds promoted Nrf2 nuclear translocation and increased the anti-oxidation downstream HO-1 protein level in HUVECs and plaque endothelium. Notably, knockdown of Nrf2 by siRNA abolished the cell protective effects of compounds and antagonized the inhibition effects of them on ROS production and NF-κB activation in oxLDL-stimulated HUVECs. Collectively, dihydrohomoplantagin and homoplantaginin protected VECs by activating Nrf2 and thus inhibited atherosclerosis in apoE-/- mice.

Molecular Characterization of Water-Soluble Brown Carbon Chromophores in Snowpack from Northern Xinjiang, China

This study reports molecular-level characterization of brown carbon (BrC) attributed to water-soluble organic carbon in six snowpack samples collected from northern Xinjiang, China. The molecular composition and light-absorbing properties of BrC chromophores were unraveled by application of high-performance liquid chromatography (HPLC) coupled to a photodiode array (PDA) detector and high-resolution mass spectrometry. The chromophores were classified into five major types, that is, (1) phenolic/lignin-derived compounds, (2) flavonoids, (3) nitroaromatics, (4) oxygenated aromatics, and (5) other chromophores. Identified chromophores account for ∼23-64% of the total light absorption measured by the PDA detector in the wavelength range of 300-370 nm. In the representative samples from urban and remote areas, oxygenated aromatics and nitroaromatics dominate the absorption in the wavelengths below and above 320 nm, respectively. The highly polluted urban sample shows the most complex HPLC-PDA chromatogram, and more other chromophores contribute to the bulk absorption. Phenolic/lignin-derived compounds are the most light-absorbing species in the soil-influenced sample. Chromophores in two remote samples exhibit ultraviolet-visible features distinct from other samples, which are attributed to flavonoids. Identification of individual chromophores and quantitative analysis of their optical properties are helpful for elucidating the roles of BrC in snow radiative balance and photochemistry.