Simultaneous determination of quercetin, kaempferol, and isorhamnetin in phytopharma-ceuticals ofHippophae rhamnoides L. by high-performance liquid chromatography with chemiluminescence detection

A Dual Emission Fluorescence Probe Based on Silicon Nanoparticles and Rhodamine B for Ratiometric Detection of Kaempferol

In this paper, blue fluorescent silicon nanoparticles (SiNPs) with outstanding optical properties and robust stability were synthesized by a simple one-step hydrothermal method. By introducing red emissive rhodamine B (RhB) into SiNPs solution, a dual emission nanoprobe (SiNPs@RhB) was constructed, which showed excellent pH stability, salt resistance and photobleaching resistance. The SiNPs@RhB probe could emit two peaks at 444 nm and 583 nm under 365 nm excitation. It was found that the fluorescence intensity of the two emission peaks decreased in different degrees with the addition of different concentrations of kaempferol (Kae). According to this phenomenon, a novel ratiometric fluorescence method was established for the detection of Kae via utilizing SiNPs@RhB as nanoprobe. The detection range and limit of detection (LOD) were 0.5 ~ 150 µM and 0.24 µM, respectively. The ratiometric fluorescence method exhibited the superiority of rapid detection, excellent stability, wide linear range and high sensitivity. The detection mechanism was studied by ultraviolet visible absorption spectra, fluorescence spectra and fluorescence lifetime. Furthermore, the method was applied to the detection of Kae in real samples (kaempferia powder, sea buckthorn granules and sea buckthorn dry emulsion).

Analytical Methods for the Determination of Quercetin and Quercetin Glycosides in Pharmaceuticals and Biological Samples

Flavonoids are plant-derived compounds that have several health benefits, including antioxidative, anti-inflammatory, anti-mutagenic, and anti-carcinogenic effects. Quercetin is a flavonoid that is widely present in various fruits, vegetables, and drinks. Accurate determination of quercetin in different samples is of great importance for its potential health benefits. This review, is an overview of sample preparation and determination methods for quercetin in diverse matrices. Previous research on sample preparation and determination methods for quercetin are summarized, highlighting the advantages and disadvantages of each method and providing insights into recent developments in quercetin sample treatment. Various analytical techniques are discussed including spectroscopic, chromatographic, electrophoretic, and electrochemical methods for the determination of quercetin and its derivatives in different samples. UV-Vis (Ultraviolet-visible) spectrophotometry is simple and inexpensive but lacks selectivity. Chromatographic techniques (HPLC, GC) offer selectivity and sensitivity, while electrophoretic and electrochemical methods provide high resolution and low detection limits, respectively. The aim of this review is to comprehensively explore the determination methods for quercetin and quercetin glycosides in diverse matrices, with emphasis on pharmaceutical and biological samples. The review also provides a theoretical basis for method development and application for the analysis of quercetin and quercetin glycosides in real samples.

Kaempferide ameliorates cisplatin-induced nephrotoxicity via inhibiting oxidative stress and inducing autophagy

Acute kidney injury (AKI) caused by anti-tumor drugs, such as cisplatin, is a severe complication with no effective treatment currently, leading to the reduction or discontinuation of chemotherapy. Natural products or herbal medicines are gradually considered as promising agents against cisplatin-induced AKI with the advantages of multi-targeting, multi-effects, and less resistance. In this study, we investigated the effects of kaempferide, a natural flavonoid extracted from the rhizome of Kaempferia galanga, in experimental AKI models in vitro and in vivo. We first conducted pharmacokinetic study in mice and found a relative stable state of kaempferide with a small amount of conversion into kaempferol. We showed that both kaempferide (10 μM) and kaempferol (10 μM) significantly inhibited cisplatin-caused injuries in immortalized proximal tubule epithelial cell line HK-2. In AKI mice induced by injection of a single dose of cisplatin (15 mg/kg), oral administration of kaempferide (50 mg/kg) either before or after cisplatin injection markedly improved renal function, and ameliorated renal tissue damage. We demonstrated that kaempferide inhibited oxidative stress and induced autophagy in cisplatin-treated mice and HK-2 cells, thus increasing tubular cell viability and decreasing immune responses to attenuate the disease progression. In addition, treatment with kaempferide significantly ameliorated ischemia-reperfusion-induced renal injury in vitro and in vivo. We conclude that kaempferide is a promising natural product for treating various AKI. This study has great implications for promotion of its use in healthcare products, and help to break through the limited use of cisplatin in the clinic.

Convenient Heme Nanorod Modified Electrode for Quercetin Sensing by Two Common Electrochemical Methods

Quercetin (Qu) is one of the most abundant flavonoids in the human diet. High concentrations of Qu can easily cause adverse effects and induce inflammation, joint pain and stiffness. In this study, Heme was used as a sensitive element and deposited and formed nanorods on a glassy carbon electrode (GCE) for the detection of Qu. The Heme/GCE sensor was characterized using scanning electron microscopy (SEM), cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) techniques. Under optimized conditions, the developed sensor presented a linear concentration ranging from 0.1 to 700 μmol·L-1 according to the CV and DPV methods. The detection limit for the sensor was 0.134 μmol·L-1 and its sensitivity was 0.12 μA·μM-1·cm-2, which were obtained from CV analysis. Through DPV analysis we obtained a detection limit of 0.063 μmol·L-1 and a sensitivity of 0.09 μA·μM-1·cm-2. Finally, this sensor was used to detect the Qu concentration in loquat leaf powder extract, with recovery between 98.55-102.89% and total R.S.D. lower than 3.70%. The constructed electrochemical sensor showed good anti-interference, repeatability and stability, indicating that it is also usable for the rapid detection of Qu in actual samples.

Ethnotherapeutic Uses and Phytochemical Composition of Physalis peruviana L.: An Overview

Background

Plant-derived medicines are widespread and continue to increase in traditional and modern medicine, especially in developing countries. Physalis peruviana L. is among the most used plants in conventional medication worldwide. This review aimed to highlight the ethnotherapeutic uses and phytochemical status of identified compounds in P. peruviana.

Methods

Data were collected from Google Scholar, PubMed/Medline, SciFinder, Science Direct, Scopus, the Wiley Online Library, Web of Science, and any other helpful search engine using Physalis peruviana as the primary keyword.

Results

Some countries, worldwide, use P. peruviana in their traditional medicine system to manage diverse ailments, mainly diseases and gastrointestinal tract disorders (25.33%). Leaf was the mostly used part (49.28%), prepared by decoction (31.58%) and overall administrated orally (53.57%) as the main route of admission. Around 502 phytoconstituents were identified in different plant parts, especially fruit (38.19%) ethanol/ethyl acetate extract. In most cases (36.17%), the solvent of the extract was not specified. Several phytochemical classes were found in the plant, especially terpenes (26.09%) and phenolic compounds (14.94%). Esters were also abundant (11.55%). In the terpenes category, carotenoids were the most abundant (11.15% followed by monoterpenes (8.76%) and diterpenes (3.18%). However, flavonoids (5.17%) followed by cinnamic acid derivatives (3.99%), monophenolic compounds (1.79%), and phenolic acids (1.33 M) are the most reported phenolic compounds. Hexadecanoic acid (palmitic acid) was the most cited (five times).

Conclusion

P. peruviana plays an essential role in managing diseases in some countries and is rich in chemical compounds, which need to be isolated and investigated pharmacologically before clinical trials.

Kaempferol and Kaempferide Attenuate Oleic Acid-Induced Lipid Accumulation and Oxidative Stress in HepG2 Cells

Nonalcoholic fatty liver disease (NAFLD) is one of the most common liver diseases which lacks ideal treatment options. Kaempferol and kaempferide, two natural flavonol compounds isolated from Hippophae rhamnoides L., were reported to exhibit a strong regulatory effect on lipid metabolism, for which the mechanism is largely unknown. In the present study, we investigated the effects of kaempferol and kaempferide on oleic acid (OA)-treated HepG2 cells, a widely used in vitro model of NAFLD. The results indicated an increased accumulation of lipid droplets and triacylglycerol (TG) by OA, which was attenuated by kaempferol and kaempferide (5, 10 and 20 μM). Western blot analysis demonstrated that kaempferol and kaempferide reduced expression of lipogenesis-related proteins, including sterol regulatory element-binding protein 1 (SREBP1), fatty acid synthase (FAS) and stearoyl-CoA desaturase 1 (SCD-1). Expression of peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT enhancer binding proteins β (C/EBPβ), two adipogenic transcription factors, was also decreased by kaempferol and kaempferide treatment. In addition, western blot analysis also demonstrated that kaempferol and kaempferide reduced expression of heme oxygenase-1 (HO-1) and nuclear transcription factor-erythroid 2-related factor 2 (Nrf2). Molecular docking was performed to identify the direct molecular targets of kaempferol and kaempferide, and their binding to SCD-1, a critical regulator in lipid metabolism, was revealed. Taken together, our findings demonstrate that kaempferol and kaempferide could attenuate OA-induced lipid accumulation and oxidative stress in HepG2 cells, which might benefit the treatment of NAFLD.

Isorhamnetin attenuates TNF-α-induced inflammation, proliferation, and migration in human bronchial epithelial cells via MAPK and NF-κB pathways

Isorhamnetin has distinct anti-inflammatory activity and inhibits cell proliferation and migration. These effects are also involved in the pathogenesis of asthma. However, the effect of isorhamnetin on bronchial epithelial cells in patients with asthma has not been examined. Cells of human bronchial epithelial cell line BEAS-2B were cultured with isorhamnetin and tumor necrosis factor (TNF)-α. The effects of isorhamnetin on BEAS-2B cell viability were assessed using CCK8 assay. The EdU (5-ethynyl-2'-deoxyuridine) cell proliferation assay was performed to assess cell proliferation. BEAS-2B cell migration was measured using Transwell and wound healing assays. Real-time PCR and enzyme-linked immunosorbent assay were conducted to measure the expression of pro-inflammatory cytokines. Protein expression levels were determined by western blotting. Immunofluorescence was used to detect nuclear translocation of nuclear factor kappa B (NF-κB). We found that isorhamnetin at 20 and 40 μM reduced the proliferation of BEAS-2B cells induced by TNF-α. Isorhamnetin significantly decreased the expression of interleukin (IL)-1β, IL-6, IL-8, and C-X-C motif chemokine ligand 10 in BEAS-2B cells induced by TNF-α. Additionally, 10 μM isorhamnetin effectively reduced cell migration induced by TNF-α. Treatment with isorhamnetin inhibited the phosphorylation of mitogen-activated protein kinase (MAPK) and NF-κB pathways induced by TNF-α. In summary, isorhamnetin inhibited the inflammation, proliferation, and migration of BEAS-2B cells by regulating the MAPK and NF-κB signaling pathways and is a drug candidate for asthma.

Fabrication of Nanosuspensions to Improve the Oral Bioavailability of Total Flavones from Hippophae rhamnoides L. and their Comparison with an Inclusion Complex

The aim of this work was to increase the solubility and oral bioavailability of isorhamnetin, kaempferol, and quercetin in the total flavones of Hippophae rhamnoides L. (TFH) by preparing their nanosuspensions (NSs) and an inclusion complex. Based on the particle size and zeta potential, P407, Soluplus, SDS, PEG-6000, and HP-β-CD were selected as stabilizers. TFH NSs and a TFH/HP-β-CD inclusion complex were prepared, and their morphology, crystallinity, molecular interactions, and cytotoxicity were investigated. Furthermore, the saturation solubility, dissolution, and pharmacokinetics of the three flavonoids in the TFH, TFH NSs, and TFH/HP-β-CD inclusion complex were compared. The five obtained TFH NSs were physically stable, and their particle sizes were all below 200 nm. The solubility and dissolution of the three active components were obviously enhanced by the formation of the TFH NSs and TFH/HP-β-CD inclusion complex. Correspondingly, the oral bioavailability of isorhamnetin, kaempferol, and quercetin increased up to 4.11-, 3.85-, and 6.73-fold, respectively, in the TFH NSs and 2.89-, 3.71-, and 9.51-fold, respectively, in the TFH/HP-β-CD inclusion complexes compared to those in the raw TFH. In brief, both NSs and inclusion complexes can improve the oral bioavailability of the three flavonoids in TFH. Taking the drug loading and the stable ratio of the multiple components into consideration, the NSs is a more promising strategy than the inclusion complex for increasing the oral bioavailability of multiple water-insoluble components in herbal extracts. Graphical abstract.

Isorhamnetin Induces Cell Cycle Arrest and Apoptosis Via Reactive Oxygen Species-Mediated AMP-Activated Protein Kinase Signaling Pathway Activation in Human Bladder Cancer Cells

Isorhamnetin is an O-methylated flavonol that is predominantly found in the fruits and leaves of various plants, which have been used for traditional herbal remedies. Although several previous studies have reported that this flavonol has diverse health-promoting effects, evidence is still lacking for the underlying molecular mechanism of its anti-cancer efficacy. In this study, we examined the anti-proliferative effect of isorhamnetin on human bladder cancer cells and found that isorhamnetin triggered the gap 2/ mitosis (G2/M) phase cell arrest and apoptosis. Our data showed that isorhamnetin decreased the expression of Wee1 and cyclin B1, but increased the expression of cyclin-dependent kinase (Cdk) inhibitor p21^WAF1/CIP1, and increased p21 was bound to Cdk1. In addition, isorhamnetin-induced apoptosis was associated with the increased expression of the Fas/Fas ligand, reduced ratio of B-cell lymphoma 2 (Bcl-2)/Bcl-2 associated X protein (Bax) expression, cytosolic release of cytochrome c, and activation of caspases. Moreover, isorhamnetin inactivated the adenosine 5′-monophosphate-activated protein kinase (AMPK) signaling pathway by diminishing the adenosine triphosphate (ATP) production due to impaired mitochondrial function. Furthermore, isorhamnetin stimulated production of intracellular reactive oxygen species (ROS); however, the interruption of ROS generation using a ROS scavenger led to an escape from isorhamnetin-mediated G2/M arrest and apoptosis. Collectively, this is the first report to show that isorhamnetin inhibited the proliferation of human bladder cancer cells by ROS-dependent arrest of the cell cycle at the G2/M phase and induction of apoptosis. Therefore, our results provide an important basis for the interpretation of the anti-cancer mechanism of isorhamnetin in bladder cancer cells and support the rationale for the need to evaluate more precise molecular mechanisms and in vivo anti-cancer properties.

Phenolic constituents and antioxidant properties of five wild species of Physalis (Solanaceae)

BACKGROUND

Fruits of wild species of the genus Physalis are consumed as food and calyces and leaves are used in traditional medicine. The phenolic composition of the species of this genus have been scarcely studied. To contribute to a better knowledge for the use of all the potential of these wild species of plants, leaves, fruits, and calyces of five wild species of the genus were analyzed for their phenolic composition and antioxidant properties.

RESULTS

Important tissue- and species-dependent variations were found. Calyces of Physalis subulata showed the highest contents of phenolics (176.58 mg of gallic acid equivalents/g dry tissue), flavonoids (39.63 mg/g dry tissue), and phenolic acids (50.57 mg of quercitrin equivalents/g dry tissue), and its leaves displayed the highest total antioxidant capacity (3.59 mg of ascorbic acid equivalents/mL) and one of the highest reduction powers (0.54 µg of ascorbic acid equivalents/mL). A high performance liquid chromatography with photodiode array detection analysis revealed a total of 28 phenolic compounds in foliar tissues (mainly kaempferol-3-O-glycosides), 16 in fruits (mainly phenolic acids), and 16 in calyces (mainly kaempferol-3-O-glycosides); the profiles of these compounds in the three types of tissue were species-specific.

CONCLUSIONS

The studied species of Physalis are important sources of phenolics with relevant antioxidant activity. The current results indicate that phenolic profiles are valuable specific chemical markers and can be relevant as food tracing and authenticity indicators for plant-based preparations involving species of Physalis.

Selective detection toward quercetin and kaempferol on NH3-plasma treated carbon nanotubes modified glassy carbon electrode

NH3-plasma treated multi-walled carbon nanotubes (pn-MWCNTs) were prepared based on the plasma technique and developed as sensing materials for detection of quercetin and kaempferol with the differential pulse voltammetry (DPV) and amperometric measurement. Such experimental parameters as pH values, accumulation potential and accumulation time were carefully investigated. The pn-MWCNTs modified electrode (pn-MWCNTs/GCE) was further explored for the analysis of quercetin and kaempferol in diluted blood serum and average recovery rates of 96.91 and 100.5% were obtained, respectively. In addition, the interference and stability measurements were evaluated under the optimized experimental conditions. More importantly, selective detection toward quercetin and kaempferol was achieved, and the proposed electrochemical sensing strategy was available to distinguish substances with similar oxidation potential.

Protective effect of total flavonoids of seabuckthorn (Hippophae rhamnoides) in simulated high-altitude polycythemia in rats

Seabuckthorn (Hippophae rhamnoides L.) has been used to treat high altitude diseases. The effects of five-week treatment with total flavonoids of seabuckthorn (35, 70, 140 mg/kg, ig) on cobalt chloride (5.5 mg/kg, ip)- and hypobaric chamber (simulating 5,000 m)-induced high-altitude polycythemia in rats were measured. Total flavonoids decreased red blood cell number, hemoglobin, hematocrit, mean corpuscular hemoglobin levels, span of red blood cell electrophoretic mobility, aggregation index of red blood cell, plasma viscosity, whole blood viscosity, and increased deformation index of red blood cell, erythropoietin level in serum. Total flavonoids increased pH, pO₂, Sp_O2, pCO₂ levels in arterial blood, and increased Na⁺, HCO₃⁻, Cl⁻, but decreased K⁺ concentrations. Total flavonoids increased mean arterial pressure, left ventricular systolic pressure, end-diastolic pressure, maximal rate of rise and decrease, decreased heart rate and protected right ventricle morphology. Changes in hemodynamic, hematologic parameters, and erythropoietin content suggest that administration of total flavonoids from seabuckthorn may be useful in the prevention of high altitude polycythaemia in rats.

Preparation and in vitro evaluation of solid dispersions of total flavones of Hippophae rhamnoides L

The purpose of this study was to enhance the dissolution of total flavones of Hippophae rhamnoides L. (TFH) by solid dispersions consisting of the drug and a polymeric carrier, poloxamer 188 (PXM). The solvent evaporation method was used to prepare solid dispersions. A 3(2) full-factorial design approach was used for optimization wherein the amount of solvent (X(1)) and the drug-to-polymer ratio (X(2)) were selected as independent variables and the percentage of TFH dissolved in 10 min (Q(10)) was selected as the dependent variable. Multiple linear regression analysis revealed that a suitable level of (1) and X(2) was required for obtaining higher dissolution of TFH from PXM solid dispersions. Solid dispersions were characterized by differential scanning calorimetry, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and dissolution tests. Characterization studies revealed that solid dispersion of TFH-PXM showed enhancement of TFH dissolution due to the conversion of TFH into a less crystalline and/or amorphous form. In conclusion, dissolution enhancement of TFH was obtained by preparing its solid dispersions in PXM using solvent method.

Determination of photoirradiated tetracyclines in water by high-performance liquid chromatography with chemiluminescence detection based reaction of rhodamine B with cerium (IV)

A simple, selective and sensitive method has been developed for the simultaneous determination of tetracycline, oxytetracycline, chlorotetracycline, demeclocycline, doxycycline and meclocycline based on reversed-phase high-performance liquid chromatography with chemiluminescence detection. The procedure was based on the chemiluminescent enhancement by photoirradiated tetracyclines of the cerium (IV)-rhodamine B system in sulphuric acid medium. The six tetracyclines were separated on an Aquasil-C18 column with a gradient elution using a mixture of acetonitrile and 0.1 mol L(-1) phosphate buffer as mobile phase, photoderivatized using a photoreactor consisting of a tube reactor coil of PFA and a 8W Xenon lamp. Under the optimized conditions, the method was validated with respect to linearity, precision, limits of detection and quantification and accuracy. The relative standard deviation (RSD) on intra-day precision was below 10% and detection limits ranged between 0.12 and 0.34 microg L(-1). The proposed method has been successfully applied to the determination of tetracyclines in surface water samples. A possible mechanism of the chemiluminescence in the system is discussed.