Kaempferol ameliorated levodopa-induced dyskinesia in experimental rats: A role of brain monoamines, cFOS, FosB, Parkin, Pdyn, TH, and p-JNK

Background:L-dopa(Levodopa)is well known for managing PD(Parkinson’s disease);however,its prolonged use caused dyskinesia(LID).Due to the varied presentation of LID,effective treatment options are scarce.Flavonoids reported their neuroprotective activity by ameliorating acetylcholinesterase,monoamine oxidase,and neuroinflammation.Kaempferol is anotherflavonoid bearing these potentials.Aim:To evaluate neuroprotective activity of kaempferol in dyskinetic rats.Methods:PD was developed in Sprague-Dawley rats by injecting combination of L-ascorbic acid(10µL)+6-OHDA(12µg)in medial forebrain bundle to induce neuronal damage in substantial nigra(SNr).LID was induced by administrating combination of L-dopa(20 mg/kg)+benserazide HCl(5 mg/kg)for 42 days.Rats were concomitantly treated with amantadine(40 mg/kg)or kaempferol(25,50,and 100 mg/kg,p.o.).Results:Kaempferol(50 and 100 mg/kg)markedly(p<0.05)inhibited LID-induced abnormal involuntary movements(AIMs)and alternation in motor function.Kaempferol administration considerably(p<0.05)inhibited reduced mitochondrial complex activities,serotonin and dopamine levels,Bcl-2,and Tyrosine hydroxylase protein expressions in SNr.Additionally,kaempferol considerably(p<0.05)attenuated increased cFOS,FosB,Parkin,and Pdyn mRNAs expressions,Bax,cleaved caspase-3,caspase-3,and pJNK proteins levels;DOPAC and 5-HIAA levels in SNr.A positive correlation was reported between cFOS,FosB,Parkin,Pdyn,apoptosis,and TH with AIMs.Conclusion:Kaempferol effectively attenuated L-dopa-induced AIMs and dyskinesia via amelioration of alterations in cFOS,FosB,Parkin,Pdyn,Tyrosine hydroxylase,and apoptosis in the brain SNr.

Preparation, characterization and evaluation of kaempferol phospholipid complex: Improvement of its solubility and biological eff ect

Kaempferol(KA),as one of the flavonoids,has extensive pharmacological properties.However,the poor solubility of KA severely limits its clinical application.In our study,the kaempferol phospholipid complex(KA-PC)has been prepared by solvent evaporation for the enhancement of the bioavailability of KA.KA-PC was verified by scanning electron microscope characterization methods.Drug loading,solubility and long-term stability were measured.The characterization results showed that KA-PC was formed through the intermolecular interaction between KA and phospholipids.The solubility of KA-PC in water was 189 times higher than that of KA,and the solubility in n-octanol was also significantly improved.Besides,pharmacodynamic studies showed that KA-PC can significantly reduce the level of serum uric acid in mice without causing renal injury.This study expanded the clinical application of KA by preparing KA-PC.

Discovery of Kaempferol,a Novel ADAM10 Inhibitor,as a Potential Treatment for Staphylococcus aureus Infection

Host-directed therapy(HDT)is an emerging novel approach for treating multidrug-resistant Staphylococcus aureus(S.aureus)infection.Functioning as the indispensable specific cellular receptor for a-toxin(Hla),a-disintegrin and metalloproteinase 10(ADAM10)is exploited to accelerate S.aureus infection through diverse mechanisms.The extraordinary contribution of ADAM10 to S.aureus pathogenesis renders it an attractive HDT target for combating S.aureus infection.Our study is the first to demonstrate the indispensable role of ADAM10 in S.aureus-induced necroptosis,and it enhances our knowledge of the role of ADAM10 in S.aureus infection.Using a fluorogenic substrate assay,we further identified kaempferol as a potent ADAM10 inhibitor that effectively protected mice from S.aureus infection by suppressing Hla-mediated barrier disruption and necroptosis.Collectively,our work presents a novel hostdirected therapeutic strategy for using the promising candidate kaempferol to treat S.aureus infection and other diseases relevant to the disordered upregulation of ADAM10.

Kaempferol improves glucose uptake in skeletal muscle via an AMPK-dependent mechanism

Insulin resistance is a hallmark of type-2 diabetes(T2D)pathogenesis.Because skeletal muscle(SkM)is the major tissue for insulin-mediated glucose disposal,insulin resistance in SkM is considered a major risk factor for developing T2D.Thus,the identifi cation of compounds that enhance the ability of SkM to take up glucose is a promising strategy for preventing T2D.Our previous work showed that kaempferol,a fl avonol present in many foods,improves insulin sensitivity in obese mice,however,the mechanism underlying this beneficial action remains unclear.Here,we show that kaempferol directly stimulates glucose uptake and prevents lipotoxicity-impaired glucose uptake in primary human SkM.Kaempferol stimulates Akt phosphorylation in a time-dependent manner in human SkM cells.The effect of kaempferol on glucose uptake was blunted by inhibition of glucose transporter 4,phosphoinositide 3-kinase(PI3K),or AMPK.In addition,kaempferol induced AMPK phosphorylation,and inhibition of AMPK prevented kaempferol-stimulated Akt phosphorylation.In vivo,kaempferol administration induced rapid glucose disposal accompanied with increased Akt and AMPK phosphorylation in SkM tissue of the mice.Taken together,these fi ndings suggest that kaempferol stimulates glucose uptake in SkM via an AMPK/Akt dependent mechanism,and it may be a viable therapeutic agent for insulin resistance.

Kaempferol and its derivatives:Biological activities and therapeutic potential

Kaempferol,a natural plant-origin flavonoid,exhibits therapeutic anti-inflammatory,antioxidant,anticancer,antidiabetic,and neuroprotective properties.Kaempferol acts within several distinct mechanisms like apoptotic induction in cancer cells,enzymatic inhibition,signalling pathway inhibition,and downregulation in cell viability during the G2/M phase of cell division.This review summarizes the therapeutic effects of kaempferol against several health ailments.The recent progress on kaempferol obtained from fruits and vegetables as an antioxidant,anti-inflammatory,anticancer,antidiabetic,and neuroprotective agent and its mechanisms of action are also discussed.In addition,kaempferol has been reported to be present in wastes and byproducts from post-fruit and vegetable processing.Thus,a paradigm shift towards valorizing fruits and vegetable industrial wastes/byproducts to obtain bioactive kaempferol can support the circular economy pillar for generating wealth from waste and for finding a sustainable alternative source.

Kaempferol attenuates cognitive deficit via regulating oxidative stress and neuroinflammation in an ovariectomized rat model of sporadic dementia

Alzheimer＇s disease（AD） is associated with oxidative stress, and ultimately results in cognitive deficit. Despite existing literature on the pathophysiology of AD, there is currently no cure for AD. The present study investigated the effects of kaempferol（Kmp） isolated from the extract of Mespilus germanica L.（medlar） leaves on cognitive impairment, hippocampal antioxidants, apoptosis, lipid peroxidation and neuro-inflammation markers in ovariectomized（OVX） rat models of sporadic AD. Kaempferol, as the main flavonoid of medlar extract has been previously known for anti-oxidative, anti-inflammatory and anti-neurotoxic effects. Thirty-two female Wistar rats were ovariectomized, and randomly divided into four groups： sham, OVX ＋ saline, OVX ＋ streptozotocin（STZ） ＋ saline, OVX ＋ STZ ＋ Kmp. Animals received intracerebroventricular injection of STZ（3 mg/kg, twice with one day interval） to establish models of sporadic AD. Intraperitoneal injection of Kmp（10 mg/kg） for 21 days was performed in the OVX ＋ STZ ＋ Kmp group. Spatial learning and memory of rats were evaluated using a Morris water maze. Finally, brain homogenates were used for biochemical analysis by enzyme-linked immunosorbent assay. The results showed a significant improvement in spatial learning and memory as evidenced by shortened escape latency and searching distance in Morris water maze in the OVX ＋ STZ ＋ Kmp group compared with the OVX ＋ STZ group. Kmp also exhibited significant elevations in brain levels of antioxidant enzymes of superoxide dismutase and glutathione, while reduction in tumor necrosis factor-α and malondialdehyde. Our results demonstrate that Kmp is capable of alleviating STZ-induced memory impairment in OVX rats, probably by elevating endogenous hippocampal antioxidants of superoxide dismutase and glutathione, and reducing neuroinflammation. This study suggests that Kmp may be a potential neuroprotective agent against cognitive deficit in AD.

Anti-viral and anti-inflammatory effects of kaempferol and quercetin and COVID-2019:A scoping review

Severe acute respiratory syndrome coronavirus type 2(SARS-CoV-2)is a novel coronavirus identified at the end of 2019.It is recognized as the causative agent of coronavirus disease 2019(COVID-19).Flavonoids have been shown to exhibit therapeutical effect on complications related to COVID-19.The present study reviews possible therapeutic benefits of flavonoids on SARS-CoV-2.The Web of Science,PubMed,Scopus,and Google Scholar were searched using keywords:“COVID-19”,“SARS-CoV-2”,“Kaempferol”and“Quercetin”in the Title/Abstract.Relevant published articles in the English language until August 2020 were considered.Kaempferol and quercetin showed antiviral properties such as inhibition of protein kinase B and phosphorylation of protein kinase and blocking effects on a selective channel(3a channel)expressed in SARS-CoV infected cells.They also reduced the level of reactive oxygen species,expression of inducible nitric oxide synthase,pro-inflammatory mediators including TNF-α,IL-1α,IL-1β,IL-6,IL-10,and IL-12 p70,and chemokines.Kaempferol and quercetin might exert beneficial effects in the control or treatment of COVID-19 because of their antiviral,antioxidant,anti-inflammatory,and immunomodulatory effects.

Neuroprotective effects of kaempferol against 2VO-induced chronic cerebral ischemia in rats

OBJECTIVE To investigate the effects of kaempferol(KAE)on chronic cerebral ischemia in rats.METHODS Chronic cerebral ischemia was induced in rats by permanent occlusion of bilateral common carotid arteries(2VO).Then,the rats with chronic cerebral ischemia were randomly divied into three groups:model group,KAE 10 and 30 mg·kg-1group.Another group rats without occlusion of common carotid arteries were used as the sham-operation group.Memory behavior was investigated by Morris water maze test.Prehensile ability was investigated by prehensile traction test.The structure of hippocampus and cortex neurons was observed with Nissel staining.In addition,the SOD activity and MDA content in brain tissue were determined.The DJ-1protein level was determined by Western blotting.RESULTS KAE 10 and 30 mg·kg-1could significantly improve cognitive impairment and prehensile traction ability(P<0.01)induced by chronic cerebral ischemia in rats.The results of the pathological analysis also suggested that KAE could ameliorate the pathological damage induced by chronic cerebral ischemia.In addition,KAE 30 mg·kg-1significantly increased the activity of SOD(P<0.05),but had no effect on the content of MDA in rat brain tissue.Western-blotting confirmed that KAE 10 and30 mg·kg-1could increase the expression of anti-oxidation proteins DJ-1 in hippocampus(P<0.01).CONCLUSION KAE may attenuate the chronic cerebral ischemic injury in rats.

Screening of Anti-tumor Effective Extracts from Sedum bulbiferum Makino and HPLC Determination of Quercetin and Kaempferol in This Herbal Medicine

[Objectives] To investigate the anti-tumor activity of Sedum bulbiferum Makino in vitro,and establish a HPLC method for determination of quercetin and kaempferol in S. bulbiferum. [Methods] The inhibitory activities of different extracts and total flavonoids of S. bulbiferum on proliferation of three kinds of cancer cells( Hep G2,EC109,SW480) were tested by MTT assay. HPLC method for determination of quercetin and kaempferol in S. bulbiferum was established. [Results]The growth and proliferation of the three kinds of cancer cells were all significantly inhibited by ethyl acetate fraction and total flavonoids isolated from S. bulbiferum. With each extraction concentration increasing,stronger anti-tumor activity was found. The linear ranges of quercetin and kaempferol were 0. 03-0. 36 μg( R = 0. 999 9) and0. 08-0. 96 μg( R = 0. 999 9),and the average recoveries were 98. 90%( RSD = 1. 15%) and 98. 27%( RSD = 1. 70%),respectively.[Conclusions]S. bulbiferum has significant anti-tumor activity in vitro. The HPLC method established was accurate,reproducible,and could be used for quality control of this crude drug.

Preparation of Magnetic Molecularly Imprinted Polymers for Selective Isolation and Determination of Kaempferol and Protoapigenone in Macrothelypteris torresiana

Novel uniform-sized magnetic molecularly imprinted polymers （MMIPs） were synthe- sized for selective recognition of active antitumor ingredients of kaempferol （KMF） and protoapi- genone （PA） in Macrothelypteris torresiana （M. torresiana） by surface molecular imprinting tech- nique in this study. Super paramagnetic core-sheU nanoparticles （γ-MPS-SiO2@Fe3O4） were used as seeds, KMF as template molecule, acrylamide （AM） as functional monomer, and N, N＇-methylene bisacrylamide （BisAM） as cross-linker. The prepared MMIPs were characterized by X-ray diffraction （XRD）, Fourier transform infrared spectrum fiT/R）, transmission electron microscopy （TEM） and thermo-gravimetric analysis （TGA）, respectively. The recognition capacity of MMIPs was 2.436 times of non-imprinted polymers. The adsorption results based on kinetics and isotherm analysis were in accordance with the pseudo-second-order model （R2=0.9980） and the Langmuir adsorption model （R2=0.9944）. The value of E （6.742 kJ/mol） calculated from the Dubinin-Radushkevich isotherm model suggested that the physical adsorption via hydrogen-bonding might be predominant. The Scatchard plot showed a single line （R2=0.9172） and demonstrated the homogeneous recognition sites on MMIPs for KMF. The magnetic solid phase extraction （MSPE） based on MMIPs as sorbent was established for fast and selective enrichment of KMF and its structural analogue PA from the crude extract of M. torresiana and then KMF and PA were detected by HPLC-UV. The established method showed good performance and satisfactory results for real sample analysis. It also showed the feasi- bility of MMIPs for selective recognition of active structural analogues from complex herbal extracts.

Combination of kaempferol and chloroquine induces glioma cell death via expansion and subsequent rupture of lysosomes

OBJECTIVE Chloroquine is considered as a potential chemotherapy and radiotherapy sensitizer,but the anticancer effect of chloroquine alone is limited.Since we found that the flavonoid kaempferol effectively sensitizes glioma cells to chloroquine-mediated cell death,we investigated the underlying mechanisms of glioma cell death induced by the combination of kaempferol and chloroquine.METHODS To examine the effect of kaempferol and/or chloroquine on various glioma cells,cell viability assay using calcein-AM and EthD-1was performed.The changes in the lysosomal structures following treatment with kaempferol and/or chloroquine were observed by electron microscopy and fluorescence microscopy using acridine orange or Lyso-tracker Red.The changes in cathepsin D proteins were analyzed by Western blotting,immunocytochemistry,and fluorescence microscopy using BODIPY FL-pepstatin.RESULTS Treatment with subtoxic doses of chloroquine,when combined with kaempferol,effectively induced cell death in various glioma cells,but not in normal astrocytes.While kaempferol treatment increased the numbers of lysosome,chloroquine treatment increased lysosomal masses.Combined treatment with kaempferol and chloroquine induced the expansion and subsequent rupture of lysosomes,leading to the spillage of the lysosomal contents into the cytosol.We found that while kaemfperol treatment increased the active mature forms of cathepsin D,chloroquine treatment completely blocked the processing of cathepsin D.The processing of cathepsin D was also blocked by the combined treatment,but the activity of cathepsin D,which was released from the lysosomes,was restored.The cell death induced by kaempferol and chloroquine in U251 MG cells was accompanied by mitochondrial dysfunction,ER stress,and DNA damage.CONCLUSION Disruption of lysosomal membrane integrity and a resultant release of lysosomal proteases may critically contribute to the irreparable damage of various organelles and glioma cell death by chloroquine plus kaempferol.

Preparation of Magnetic Fluorescent Dual-drug Nanocomposites for Codelivery of Kaempferol and Paclitaxel

Magnetic fluorescent dual-drug nanocomposites（MFDDs） were developed with the aim of simultaneouly delivering two different anticancer drugs, kaempferol（KAE） and paclitaxel（PTX）. Firstly, Fe3O4/bovine serum albumin（Fe3O4/BSA） composite microspheres with physically entrapped KAE were prepared, then microspheres were modified with PTX/graphene quantum dots（PTX/GQDs） through chemically bonding, and the MFDDs were obtained. The properties of nancomposites were characterized by X-ray diffractometry, Fourier-transform infrared spectroscopy, transmission electron microscopy, vibrating sample magnetometry and X-ray fluorescence spectrometry. It was found that the superparamagnetic nanocomposites had ultrafine size（below 110 nm）, high saturation magnetization of 24.36 emu/g, and significant fluorescence. Furthermore, the cumulative in vitro release of the MFDDs exhibited controlled drug release. Cell viability experiments confirmed that the co-administration of KAE with PTX had a superior cytotoxicity to the Hela cells compared with single drug-loaded forms. Therefore, dual anticancer drug-loaded MFDDs have the potential to be used for cancer combined chemotherapy.

Determination of the Content of Kaempferol from Fermented Ginkgo( Ginkgo biloba L.) Leaves

[Objectives] This study was conducted to determine kaempferol content in ginkgo( Ginkgo biloba L.) leaves subjected to microbial fermentation.[Methods]Bacillus licheniformis was selected for solid-state fermentation of ginkgo leaves,and the content of kaempferol in ginkgo leaves was determined by RPHPLC method. At first,methanol was used to extract flavonoid glycosides,which were then hydrolyzed by hydrochloric acid solution. HPLC was performed with Platisil ODS column C18( 150 mm ×4. 6 mm,5 μm) using mobile phase Vmethanol∶ Vwater( 0. 4% phosphoric acid solution) = 55∶45 at a flow rate of 1 ml/min,and the eluate was detected with a shimadzu HPLC ultraviolet detector at 360 nm. [Results]With kaempferol as the reference substance,the correlation coefficient was0. 999 2 in the range of 0. 001 06-0. 016 96 g/L. The content in the fermented product was less than that in the non-fermented product by 28%. [Conclusions]The method is simple,accurate,and is suitable for determination of kaempferol. This study will provide an experimental basis for the development and utilization of ginkgo.

Kaempferol inhibits Pseudorabies virus replication in vitro through regulation of MAPKs and NF-κB signaling pathways

Pseudorabies virus(PRV),in the family Herpesviridae,is a pathogen of Aujeszky’s disease,which causes great economic losses to the pig industry.Recent outbreaks of Pseudorabies imply that new control measures are urgently needed.The present study shows that kaempferol is a candidate drug for controlling PRV infection,as it possesses the ability to inhibit PRV replication in a dose-dependent manner in vitro.Kaempferol at a concentration of 52.40μmol L^(-1) could decrease PRV-induced cell death by 90%.With an 50%inhibitory concentration(IC50)value of 25.57μmol L^(-1),kaempferol was more effective than acyclovir(positive control)which has an IC50 value of 54.97μmol L^(-1).A mode of action study indicated that kaempferol inhibited viral penetration and replication stages,decreasing viral loads by 4-and 30-fold,respectively.Addition of kaempferol within 16 h post infection(hpi)could significantly inhibit virus replication,and viral genome copies were decreased by almost 15-fold when kaempferol was added at 2 hpi.Kaempferol regulated the NF-κB and MAPKs signaling pathways involved in PRV infection and changed the levels of the target genes of the MAPKs(ATF-2 and c-Jun)and NF-κB(IL-1α,IL-1βand IL-2)signaling pathways.The findings of the current study suggest that kaempferol could be an alternative measure to control PRV infection.

Competition between anthocyanin and kaempferol glycosides biosynthesis affects pollen tube growth and seed set of Malus

Flavonoids play important roles in regulating plant growth and development.In this study,three kaempferol 3-O-glycosides were identi fi ed and mainly accumulated in fl owers but not in leaves or fruits of Malus.In Malus,fl ower petal color is normally white,but some genotypes have red fl owers containing anthocyanin.Anthocyanin biosynthesis appears to be in competition with kaempferol 3-O-glycosides production and controlled by the biosynthetic genes.The white fl ower Malus genotypes had better-developed seeds than the red fl ower genotypes.In fl owers,the overexpression of MYB10 in Malus domestica enhanced the accumulation of anthocyanin,but decreased that of kaempferol 3-O-glycosides.After pollination the transgenic plants showed slower pollen tube growth and fewer developed seeds.Exogenous application ofdifferent fl avonoid compounds suggested that kaempferol 3-O-glycosides,especially kaempferol 3-O-rhamnoside,regulated pollen tube growth and seed set rather than cyanidin or quercetin 3-O-glycosides.It was found that kaempferol 3-O-rhamnoside might regulate pollen tube growth through effects on auxin,the Rho of plants(ROP)GTPases,calcium and the phosphoinositides signaling pathway.With the inhibition of auxin transport,the transcription levels of Heat Shock Proteins(HSPs)and ROP GTPases were downregulated while the levels were not changed or even enhanced when blocking calcium signaling,suggesting that HSPs and ROP GTPases were downstream of auxin signaling,but upstream of calcium signaling.In summary,kaempferol glycoside concentrations in pistils correlated with auxin transport,the transcription of HSPs and ROP GTPases,and calcium signaling in pollen tubes,culminating in changes to pollen tube growth and seed set.

Kaempferol and docetaxel diminish side population and down-regulate some cancer stem cell markers in breast cancer cell line MCF-7

Cancer stem cells(CSCs)are a small subpopulation of cancer cells whose resistance to chemotherapy and radiotherapy plays a pivotal role in treatment failure,tumor recurrence and metastasis.Today,the ability of many phytochemicals in targeting of CSCs has been identified.Kaempferol is a plant phytoestrogen that was recognized as a useful agent for targeting cancer cells by apoptosis induction,cell cycle arrest and inhibition of angiogenesis,migration,and invasion of cancer cells.In this study,we compared the effect of docetaxel as a common breast cancer chemotherapy drug and kaempferol on MCF-7 breast CSCs.Results showed that both docetaxel and kaempferol caused a dose-dependent reduction in cell proliferation.Rhodamin 123 dye staining and flow cytometry analysis revealed that after docetaxel and kaempferol treatment,SP cells proportion of MCF-7 decreased to 11.83±2.2% and 3±0.25% respectively relative to proportion of untreated control cells(23±3.2%).Moreover,real time PCR results showed that kaempferol treatment of MCF-7 was more effective than docetaxel in down-regulating the CSC-associated markers(i.e.oct4,nanog,abcb1 and aldh1a1).Taken together,these results indicate that kaempferol is an effective anti-CSCs agent,therefore it may be a therapeutic strategy for eradicating breast cancer through the elimination of CSCs.

Kaempferol attenuates knee osteoarthritis via inhibiting cartilage apoptosis in mice

Objective:To study the mechanism of kaempferol in the intervention of knee osteoarthritis(KOA)in mice by inhibiting cartilage apoptosis.Methods:Firstly,the target genes of kaempferol were retrieved via TCMSP,and the genes related to KOA were obtained by GeneCards,OMIM,PharmGKB,TTD,and Drugbank databases.Then GO enrichment analysis and KEGG signaling pathway analysis were also performed.Subsequently,18 male C57 mice were randomly divided into the sham operation group,the model group,and the kaempferol group(50 mg/kg).Except for the sham operation group,the KOA mouse model was induced by destabilization of medial meniscus surgery.The sham operation group and model group were given the same amount of normal saline daily for 8 weeks while the kaempferol group was given 50 mg/kg kaempferol intragastrically.Results:A total of 63 targets of kaempferol were found that included 35 common target genes with KOA.GO and KEGG analyses showed that biological processes such as extrinsic apoptotic signaling pathway and response to oxidative stress,as well as signaling pathways such as cell apoptosis and regulation of TNF were closely related to common target genes.Molecular docking results also showed kaempferol has good binding properties with predicted targets Bcl-2,BAX,and CASP3.Compared with the model group,the pathological changes of cartilage in the kaempferol group were significantly reduced,OARSI scores were significantly decreased(P<0.001),and cartilage area was increased(P<0.01).In addition,Western blot analysis showed that kaempferol significantly decreased the protein expression of BAX and CASP3(P<0.01,P<0.05),and increased the protein expression of BCL-2(P<0.05).Conclusion:The treatment of KOA with kaempferol has the characteristics of multi-target and multi-pathway,and the mechanism may be related to the regulation of key genes such as Bcl-2,BAX,and CASP3 to inhibit cartilage apoptosis.

Content Determination of Quercetin and Kaempferol in Flueggea virosa(Roxb.ex Wild.)Baill.

[Objectives]The purpose was to determine the contents of quercetin and kaempferol in Flueggea virosa(Roxb.ex Wild.)Baill.,thereby providing reference data for the research and application of F.virosa.[Methods]Quercetin and kaempferol in F.virosa were extracted with ultrasonic method,using dilute hydrochloric acid-methanol(1∶10)solution as the extraction solvent,and their contents were determined with RP-HPLC.[Results]The contents of quercetin and kaempferol in F.virosa were 0.2336 and 0.3272 mg/g,respectively.[Conclusions]The method has high speed,high resolution,high sensitivity,accurate and reliable detection results,and can be used as a method for the determination of quercetin and kaempferol in F.virosa.

Determination of Kaempferol Content in 10 Batches of Different Production Areas of Yao Medicine Lysimachia foenum-graecum Hance

[Objectives]To determine the kaempferol content in Yao medicine Lysimachia foenum-graecum Hance.[Methods]The high performance liquid chromatography(HPLC)method was used.The chromatographic column:Inertsil ODS-3 C18 column(4.60 mm×250 mm,5μm);mobile phase:acetonitrile-0.1%glacial acetic acid;flow rate:1.0 mL/min;column temperature:30℃;detection wavelength:360 nm;sample injection volume:10μL.[Results]The kaempferol content in Yao medicine L.foenum-graecum was determined,Y=20652X-151098(R=0.9997)shows a good linear relationship within the linear range of 9.80-156.8μg/mL.[Conclusions]The high performance liquid chromatography(HPLC)method was established for determining the kaempferol content in Yao medicine L.foenum-graecum.This method is expected to provide a scientific basis for the formulation of quality control methods for L.foenum-graecum.

天然黄酮山奈酚(Kaempferol)与Alpha-葡萄糖苷酶的相互作用机制分析

α-葡萄糖苷酶是治疗2型糖尿病的重要药物靶点之一,而基于天然产物寻找先导化合物是药物开发的重要途径。研究通过酶动力学实验和分子对接初步探讨了天然黄酮山奈酚与α-葡萄糖苷酶之间的相互作用规律。结果表明,山奈酚非竞争性抑制α-葡萄糖苷酶,并呈现浓度依赖性(IC 50=91.11±1.12μM);山奈酚可逆性结合于α-葡萄糖苷酶而呈现抑制效应。山奈酚能够显著性淬灭α-葡萄糖苷酶的内置荧光,诱使酶二级结构构象发生改变。此外,分子对接分析表明,抑制剂山奈酚可结合于α-葡萄糖苷酶活性中心,氢键和疏水性相互作用对于配体α-葡萄糖苷酶复合物构象稳定性的维系有着重要作用。