Compounds Kaempferol Research Articles

Sesquiterpenoids and flavonoids from Pteris multifida Poir.

Phytochemical research of Pteris multifida Poir. led to the isolation of fifteen compounds, including six flavonoids (1–6) and nine sesquiterpenoids (7–15). Their structures were characterized by NMR, MS, ORD and CD data. Compounds kaempferol 3-O-α-L-rhamnoside-7-O-β-D-glucoside (1), myricetin 3-O-β-D-glucoside (2), kaempferol 3-O-β-D-glucoside (4), luteolin-7-O-β-D-rutinoside (5), quercetin-3-O-α-L-rhamnopyranoside (6), (2S,3S)-12-hydroxypterosin Q (7), (2S,3S)-pterosin Q (8), 2-hydroxypterosin C (9) and (2S)-12-hydroxypterosin A (10) were first isolated from P. multifida, and compounds 1–2 and 10 were first isolated from the family Pteridaceae. Furthermore, the chemotaxonomic significance of the isolates was discussed.

An ecological study of the fern Asplenium Trichomanes L. in Iraq with a reference to its phytochemical and antioxidant activity

A number of ferns are known to have ornamental, medicinal and ethnobotanical importance all over the world. In spite of the presence of numerous fern species such as Equisetum, Adiantum, Asplenium and Cheilanthes species all over our country (Iraq) particularly the Kurdistan part, still, such information in this area is quite rare. Asplenium Trichomonas L. is a genus of one of the widest groups of Asplenideae (maidenhair spleen worts). It is a megaphyllous, homosporous fern, which was found at an elevation above 1600 m.a.s.l. Samples were collected from the Taweela area in Kurdistan of Iraq, the phytochemical and antioxidant activity of the plant was dealt with in the current investigation through the methanol extract method of ferns. The result revealed positive detection of few numbers of flavonoid compounds, among which kaempferol compound showed the highest concentration (227 μg/ml) whereas kaempferide 3-0 glycoside showed the lowest concentration (130.3 μg/ ml), six phenolic compounds were identified through HPLC technique among which (Kaempferol, Quercetin, Myrstin, Rutin, Kea.3-o-glycoside, and Leutolin), also anti-oxidant activity recorded (1c50) it had exceeded (2.27 μg/m1). In contrast the positive control (Ascorbic acid) 0.018 mg/ ml. The present study has been devoted to the distribution of Asplenium Trichomanes L in Iraq with reference to it is a phytochemical and anti-oxidant activity for the first time in the region. In years to come, undoubtedly this will follow with more investigations on fern wealth in Iraq so it will reduce the existing gap in the knowledge in this respect.

An online target and rapid screening method for α-glucosidase inhibitors based on capillary electrophoresis.

Screening enzymatic active compounds is one of the important fields in drug research. α-Glucosidase can hydrolyze carbohydrates to monosaccharides after meals and lead to the rise of blood glucose levels in human body. Thus, the inhibition of α-glucosidase activity is an effective approach for the diabetes treatment. In this work, we developed a new method to simultaneously screen multiple bioactive compounds within a single CE running. The affect factors on the method performance, including injection, mixing, incubation, separation and detection, were carefully analyzed and discussed. Under the optimum, the mixture consisting of two internal standards (DMSO and 4-nitrophenol) and five compounds (lyoniresinol, hydroxytyrosol, rutin, kaempferol, and quercetin) was simultaneously screened, and kaempferol and quercetin showed stronger activity and this conclusion was also supported by offline assay. Furthermore, molecular docking was employed for investigating its interaction mechanism. Eventually, the established method has been applied to screen potential α-glucosidase inhibitors from an extract of Lycium barbarum and the peak area of rutin, taxifolin, quercetin, and chlorogenic acid in L. barbarum samples changed before and after the enzymatic reaction, confirming that these four compounds had potential inhibitory activities, which was consistent with the literature data. The present work provides a promising method for the target and rapid discovery of bioactive compounds from a plant extract or mixture.

A review on nutritional value, phytochemical and pharmacological attributes of Foeniculum vulgare Mill

Foeniculum vulgare is a cuisine spice of the Apiaceae genus, which is extensively cultivated in the world's tropical and temperate areas. Fennel seeds are developed mostly from dry and semi-dry regions in India. Recent studies have revealed pharmacological properties including antimicrobials, antidiabetic, antioxidants, anticancer and other activities. Fennel contains flavonoids, glycosides and other phytoconstituents present in it which used in medicinal ailments purpose. Phenolic compounds present in fennel can promote to the human health. Trans-anethole, estragole, fenchone and bioactive compounds kaempferol, quercetin, rosmarinic acid have been isolated from this plant and several associate with prospective human body mechanisms. The objective of this review to focusing on the nutritional value, botanical studies, phytochemicals and some major pharmacological actions of fennel to reveal the medicinal potential and future investigation aspects.

Beneficial Actions of Orostachys japonica and Its Compounds against Tumors via MAPK Signaling Pathways.

Tumors are one of the most life-threatening diseases, and a variety of cancer treatment options have been continuously introduced in order to overcome cancer and improve conventional therapy. Orostachys japonica (O. japonica), which is a perennial plant belonging to the genus Orostachys of the Crassulaceae family, has been revealed to exhibit pharmacological properties against various tumors in numerous studies. The present review aimed to discuss the biological actions and underlying molecular mechanisms of O. japonica and its representative compounds—kaempferol and quercetin—against tumors. O. japonica reportedly has antiproliferative, anti-angiogenic, and antimetastatic activities against various types of malignant tumors through the induction of apoptosis and cell cycle arrest, a blockade of downstream vascular endothelial growth factor (VEGF)-VEGFR2 pathways, and the regulation of epithelial-to-mesenchymal transition. In addition, emerging studies have highlighted the antitumor efficacy of kaempferol and quercetin. Interestingly, it was found that alterations of the mitogen-activated protein kinase (MAPK) signaling cascades are involved in the pivotal mechanisms of the antitumor effects of O. japonica and its two compounds against cancer cell overgrowth, angiogenesis, and metastasis. In summary, O. japonica could be considered a preventive and therapeutic medicinal plant which exhibits antitumor actions by reversing altered patterns of MAPK cascades, and kaempferol and quercetin might be potential components that can contribute to the efficacy and underlying mechanism of O. japonica.

Phenolic and free amino acid profiles of bee bread and bee pollen with the same botanical origin – similarities and differences

In this study, the chemical profile of bee pollen (BP) and bee bread (BB) samples collected from the same beehive were analyzed by LC–MS/MS (liquid chromatography technique coupled with tandem mass spectrometry), providing the identification of 23 phenolic compounds and 42 free amino acids (FAAs). Rutin was the phenolic compound with the highest rate of occurrence in both BP and BB samples. However, concentrations of protocatechuic acid, 2,5-dihydroxybenzoic acid and kaempferol compounds were significantly higher in BB samples than in BP samples from the same hive probably as result of microbial activity and glycosides degradation. The obtained data revealed that the phenolic profiles of the samples differ not only by the type of a product but also by region. Among FAAs proline was the predominant compound in all the analyzed BP and BB samples followed by l-asparagine (BP samples) and l-aspartic acid (BP and BB samples). A high content of proline can be used as a parameter of sample freshness. Also, Principal Component Analysis (PCA) and Cluster analysis proved the possibility of using phlorizin as a chemotaxonomic marker for Rosaceae (Malus or Prunus genus) pollen presence in BP1 sample. In addition, amino acid profile had higher impact on BP and BB sample differentiation due to lower FAAs content in BB samples probably caused by microbial activity. To the best of our knowledge, this study is the first to compare the individual phenolic compounds and free amino acids of bee pollen and bee bread samples with the same botanical origin (predominantly originated from plants belonging to the following families: Asteraceae, Fabaceae, Plantaginaceae and Rosaceae).

Optimization for the extraction of polyphenols from Inonotus obliquus and its antioxidation activity

In order to study the extraction process and antioxidative activity of Inonotus obliquus polyphenols (IOP), the optimal extraction process was determined by orthogonal experiment optimization. The clearance rate of DPPH and hydroxyl radicals were used as indicators to evaluate the antioxidant activity of IOP. The results showed that the optimum extraction conditions were as follows: ethanol concentration of 50%, solid–liquid ratio of 1:20, temperature of 60 °C, and 90 min. Under these conditions, the extraction yield of IOP was 2.84%. The antioxidant capacity of extracts appeared to be IOP dose-dependent, while it also presented stronger ferric reducing antioxidant power (FRAP). High Performance Liquid Chromatography (HPLC-MS) analysis indicated that the major identified polyphenol compounds extracted at the optimal conditions were ten compounds (procyanidin, caffeic acid, p-coumaric acid, isorhamnetin-3-O-glucoside, astilbin, tangeretin, gallic acid, kaempferol, quercetin, and catechin 7-xyloside). These findings indicate that I. obliquus polyphenols have the potential to be developed as a natural antioxidant and have a good application prospect.

Study on mechanism of fangyi qingfei decoction against Covid-19 associated lung and kidney injury based on network pharmacology and molecular docking

Introduction: The outbreak of Coronavirus Disease 2019 (COVID-19) in Wuhan, China, was caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The present study aims to explore the potential antiviral and lung or kidney tissue-protecting mechanisms of Fangyi Qingfei Decoction (FYQFD) on COVID-19 based on network pharmacology and molecular docking method. Materials and methods: Traditional Chinese Medicine Systems Pharmacology (TCMSP) was used to search the compounds and targets of FYQFD, and GeneCards database was used to search the pathological targets of acute lung or kidney injury;The intersection method was used to obtain the targets related to the therapeutic effect of FYQFD. Protein-protein interaction (PPI) network was constructed by Search Tool For Recurring Instances of Neighbouring Genes (STRING) database and the hub target genes were identified by calculating node degree. Molecular docking was performed based on the hub compounds and hub target genes and the SARS-CoV-2 3CL hydrolase (SARS-CoV-2 3CLpro) and angiotensin converting enzyme II (ACE2), respectively. Results: Total 159 potential active components, corresponding to 203 targets associated lung and kidney injury, were screened from FYQFD. GO function enrichment analysis revealed 123 biological process (BP) items (P < 0.05), 75 signal pathways (P < 0.05) were screened out after KEGG pathway enrichment analysis. Furthermore, molecular docking indicated that main active compounds kaempferol, quercetin, wogonin, luteolin and acacetin in FYQFD exhibited higher affinity among AKT1, ALB, IL6, TP53, VEGFA, TNF, JUN, CASP3, EGFR, MAPK1 with SARS-CoV-2 3CLpro and ACE2. Conclusion: By this procedure, the present study enhanced the understanding of the potential therapeutic mechanism of FYQFD, that the partial compounds in FYQFD can bind with SARS-CoV-2 3CLpro and ACE2, and acting on many targets to regulate multiple signaling pathways, thus exerting the therapeutic effect on COVID-19.

İki Calendula Türünde Belirli Fenolik Bileşiklerin ve Karotenoidin Hplc ile Analizi

Asteraceae familyasına ait, tıbbi amaçla kullanılan bir süs bitkisi olan Calendula officinalis (tıbbi nergis, aynısefa) antikanser, antimikrobiyal, antioksidan, antitümör gibi çeşitli tıbbi aktivitelere sahiptir. HPLC ile analizi yapılması planlanan kuersetin (6,445 dak), kaemferol (11,246 dak), kafeik asit (2,333 dak), beta karoten (9,614 dak) standardlarının en iyi piki ve en fazla miktarı verdiği tutulma zamanı belirlenmiştir. Bu metabolitler için en uygun olan HPLC koşulları saptanmıştır. Bu iki Calendula türünün 0., 15., 30., 45., 60. günlerindeki fide yapraklarındaki kuersetin, kaemferol, kefeik asit ve beta karoten miktarları karşılaştırılmıştır. Yapraklarda kafeik asit ve beta karoten tespit edilmiştir. Fakat kuersetin ve kaemferol bileşikleri tespit edilememiştir. C. officinalis türünün kafeik asit ve beta karoten miktarının, C. arvensis türüne göre daha fazla olduğu belirlenmiştir. C. officinalis ve C. arvensis fidelerinin her ikisinde de en yüksek kafeik asit (C. officinalis için 0,4042±0,0123 µg/g kuru ağırlık, C. arvensis için 0,1918±0,0437 µg/g kuru ağırlık) ve beta karoten miktarları (C. officinalis için 0,8520±0,0692 µg/g kuru ağırlık, C. arvensis için 0,6389±0,0189 µg/g kuru ağırlık) 60. günde saptanmıştır. Ayrıca fide gelişim dönemine göre, bu metabolitlerin miktarının farklılık gösterdiği saptanmıştır.

Potential of Plant Bioactive Compounds as SARS-CoV-2 Main Protease (Mpro) and Spike (S) Glycoprotein Inhibitors: A Molecular Docking Study.

Since the outbreak of the COVID-19 (coronavirus disease 19) pandemic, researchers have been trying to investigate several active compounds found in plants that have the potential to inhibit the proliferation of SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2). The present study aimed to evaluate bioactive compounds found in plants using a molecular docking approach to inhibit the main protease (Mpro) and spike (S) glycoprotein of SARS-CoV-2. The evaluation was performed on the docking scores calculated using AutoDock Vina (AV) as a docking engine. A rule of five (Ro5) was calculated to determine whether a compound meets the criteria as an active drug orally in humans. The determination of the docking score was performed by selecting the best conformation of the protein-ligand complex that had the highest affinity (most negative Gibbs' free energy of binding/ΔG). As a comparison, nelfinavir (an antiretroviral drug), chloroquine, and hydroxychloroquine sulfate (antimalarial drugs recommended by the FDA as emergency drugs) were used. The results showed that hesperidin, nabiximols, pectolinarin, epigallocatechin gallate, and rhoifolin had better poses than nelfinavir, chloroquine, and hydroxychloroquine sulfate as spike glycoprotein inhibitors. Hesperidin, rhoifolin, pectolinarin, and nabiximols had about the same pose as nelfinavir but were better than chloroquine and hydroxychloroquine sulfate as Mpro inhibitors. This finding implied that several natural compounds of plants evaluated in this study showed better binding free energy compared to nelfinavir, chloroquine, and hydroxychloroquine sulfate, which so far are recommended in the treatment of COVID-19. From quantum chemical DFT calculations, the ascending order of chemical reactivity of selected compounds was pectolinarin > hesperidin > rhoifolin > morin > epigallocatechin gallate. All isolated compounds' C=O regions are preferable for an electrophilic attack, and O-H regions are suitable for a nucleophilic attack. Furthermore, Homo-Lumo and global descriptor values indicated a satisfactory remarkable profile for the selected compounds. As judged by the RO5 and previous study by others, the compounds kaempferol, herbacetin, eugenol, and 6-shogaol have good oral bioavailability, so they are also seen as promising candidates for the development of drugs to treat infections caused by SARS-CoV-2. The present study identified plant-based compounds that can be further investigated in vitro and in vivo as lead compounds against SARS-CoV-2.

Synthesis and application of silver nanoparticles using Cissus quadrangularis

This current study mainly focuses on synthesis of silver nanoparticles in an eco-friendly method using Cissus quadrangularis (CqNp), its characterization and understanding its potential biomedical applications. The CqNp’s were confirmed using UV-vis spectroscopy, FT-IR and the structure of the nanoparticles were analyzed by FESEM and EDAX. Anti-oxidant assay conducted with the plant and the CqNp’s, against the standard ascorbic acid showed its potential to be an antioxidant agent. α-amylase inhibition assay revealed the effectiveness of the CqNp’s which were almost similar to that of the standard acarbose. Molecular docking was performed for the plant compounds kaempferol and quercetin to find its binding energy, interacting residues and type of interaction. To the best of our knowledge, this is the first report on confirming the antioxidant and α-amylase inhibition potential of Cissus quadrangularis mediated nanoparticles (CqNps). Hence, this green approach can be further utilized to develop a potent anti-diabetic drug.

In vitro anti-aging activities of ginkgo biloba leaf extract and its chemical constituents

Abstract To determine in vitro anti-aging activity and identify the active chemical constituents in Ginkgo leaf extracts. The antioxidant properties of Ginkgo biloba leaves extracts were evaluated using 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) scavenging and 2,2’-azino-bis (3-ethylbenzothiazoline)-6 sulfonic acid radical (ABTS) scavenging assays. The inhibitory effects of extracts and chemical constituents on reactive oxygen species, matrix metalloproteinase-1 (MMP-1) and collagen tpye I level were tested using human dermal fibroblasts (HDFs). Reverse-phase liquid chromatography (RPLC) and ultra-performance liquid chromatography tandem mass spectroscopy (UPLC/MS/MS) were used to quantitatively analyze flavonoids and terpene trilactones in the extraction. The established quantitative analysis method was validated according to the regulatory guidelines. The extraction and compounds kaempferol 3-O-β-D-glucopyranoside, isorhamnetin-3-O-glucoside, myricetin, ginkgolide A and bilobalide could have potential anti-aging activities of G. biloba. The results suggest that G. biloba could be used as anti-aging products and as a cosmetic and medicinal raw material.

Biopesticide synergy when combining plant flavonoids and entomopathogenic baculovirus

Four crop plants known to be hosts for the lepidopteran Trichoplusia ni (soybean, green bean, cotton, and cabbage) were treated with the biopesticide AfMNPV baculovirus in a dosage response assay. Treated soybean had, on average, a 6-fold increase in virus activity compared with the other crops. Leaf trichomes on soybeans were not found to be responsible for the observed increase of insecticidal activity. Three flavonoid compounds (daidzein, genistein, and kaempferol) were uniquely found only in the soybean crop, and were not detected in cotton, cabbage, or green bean plant matter. The individual flavonoid compounds did not cause T ni. mortality in no-virus assays when incorporated into artificial insect diet. The combination of the three flavonoid compounds at leaf level concentrations significantly increased baculovirus activity in diet incorporation assays. When the daidzein, genistein, and kaempferol were added to artificial diet, at 3.5–6.5 × leaf level concentrations, virus activity increased 1.5, 2.3, and 4.2-fold for each respective flavonoid. The soybean flavonoid compounds were found to synergistically improve baculovirus activity against T. ni.

α-Amylase Inhibition Activities by Flavonoid Compounds from Panda Plants (Kalanchoe tomentosa)

Diabetes mellitus (DM) is one of the major health problems. One way to deal with diabetes mellitus is by inhibiting the work of enzymes that hydrolyze carbohydrates, thereby reducing glucose absorption. The enzyme that plays a role in the breakdown of starch into simple sugars is the α-amylase. The genus Kalanchoe or Panda plant has been widely reported to contain a variety of secondary metabolites that have several activities such as antimalarial, antibacterial, antidiabetic, and anticancer potential. This study aims to isolate, determine the chemical structure, and test the inhibitory activity of α-amylase from the ethyl acetate fraction of K. tomentosa leaves. The isolation stage began with the maceration process with n-hexane and fractionated with ethyl acetate. Ethyl acetate extract was refracted using a gradient liquid vacuum chromatography (KCV) method (n-hexane: ethyl acetate: methanol). Repeated gravity columns separated the fraction of KCV results and preparative thin-layer chromatography (TLC-P) to obtain isolate pure. Isolate pure was characterized using several spectroscopic methods, including UV-Vis, IR, NMR. Determination of the structure of the compound against isolate pure shows that this isolate is a 3,7,4’-trihydroxyflavonol or kaempferol compound. The results of the test activity of 3,7,4’-trihydroxyflavonol compounds in inhibiting the enzyme α-amylase in vitro showed an IC50 value of 346 µU/mL. The results obtained indicate that the IC50 value is higher than that of the Acarbose, which was 39.3 µU/mL.

Polyphenolic Profiles of Yellow Bean Seed Coats and Their Relationship with Iron Bioavailability.

Previous work with Caco-2 cell cultures has shown that individual polyphenols can either promote or inhibit iron uptake. This investigation was designed to characterize the relationship between iron bioavailability and seed coat polyphenol composition in a panel of 14 yellow beans representing five market classes with the potential for fast cooking time and high iron content. The study included two white and two red mottled bean lines, which represent high and low iron bioavailability capacity in dry beans, respectively. Polyphenols were measured quantitatively by high-performance liquid chromatography-mass spectrometry (HPLC-MS)/UV and iron bioavailability of seed coat extracts was measured in Caco-2 assays. Thirteen of the yellow bean seed types contained high concentrations (up to 35.3 ± 2.7 μmol/g) of kaempferol 3-glucoside (k 3-g), a known promoter of iron uptake. A general association between the ratio of promoting to inhibiting polyphenols (P/I) and iron uptake was observed. The presence of iron uptake inhibiting condensed tannins proportionately countered the promotional effects of kaempferol compounds. Unidentified factors present in seed coats other than polyphenols also appeared to affect iron uptake.

Molecular docking tangeretin and kaempferol compound against antiapoptotic Bcl-xL: in silico study

The plants that can be developed as a chemopreventive agent are orange peel (Citrus reticulata) and tea leaves (Camellia sinensis). This study aims to determine the chemopreventive agent of tangeretin and kaempferol in silico. In silico test was performed molecular docking by using Vina Autodock Software by deprecating tangeretin and kaempferol compounds against target protein Bcl-xL. Tangeretin and kaempferol have an affinity to the protein with score -5,8 kkal/mol and -6,4 kkal/mol, respectively. Tangeretin has a high potency in inhibiting activity against Bcl-xL protein, while kaempferol has less potency in inhibition of Bcl-xL protein.

Inhibitory effects of shell of Camellia oleifera Abel extract on mushroom tyrosinase and human skin melanin.

As an oil production byproducts, the shell of Camellia oleifera Abel (SC) is usually discarded in the dump. However, previous investigations suggested that the SC could provide valuable bioactive materials. The objectives of this study were to examine the ability of SC extract to inhibit in vitro tyrosinase activity and the melanin inhibition effects of cosmetic formulations containing SC 1,3-butanediol extract in human volunteers. The cell viability was determined using a WTT assay. A mushroom tyrosinase was used to evaluate the anti-tyrosinase activity of the SC extract. The placebo (no extract) or test (SC 1,3-butanediol extract) or positive control (kojic acid) cosmetic cream was applied on face of volunteers(30 female subjects) three times a day for 8weeks. The active compounds in SC extract were screened using liquid chromatography-high-resolution mass spectrometry (UHPLC-QTOF). The result showed that the cytotoxicity of SC extract is insignificant when the concentration of SC extract is below 160µg/mL. In addition, SC extract dose dependently inhibited tyrosinase activity and SC 1,3-butanediol extract possessed a stronger inhibitory activity than methanol extract and water extract. Clinical evaluations revealed that facial melanin levels of the volunteers receiving cosmetic formulations (containing SC 1,3-butanediol extract) were decreased 59% from baseline in 6th weeks, whereas the placebo group showed no effect. SC 1,3-butanediol extract was detected to contain 12 kaempferol compounds, significantly, kaempferol 3-O-[α-rhamnopyranosyl-(1→6)-β-glucopyranoside] and kaempferol-3,7-O-α-L-dirhamnoside are the major compounds. These results indicate that SC extract can be used as a natural skin-whitening agent in cosmetic products.

The Phenolic compound Kaempferol overcomes 5-fluorouracil resistance in human resistant LS174 colon cancer cells

Resistance to 5-Fluorouracil chemotherapy is a major cause of therapeutic failure in colon cancer cure. Development of combined therapies constitutes an effective strategy to inhibit cancer cells and prevent the emergence of drug resistance. For this purpose, we investigated the anti-tumoral effect of thirteen phenolic compounds, from the Tunisian quince Cydonia oblonga Miller, alone or combined to 5-FU, on the human 5-FU-resistant LS174-R colon cancer cells in comparison to parental cells. Our results showed that only Kaempferol was able to chemo-sensitize 5-FU-resistant LS174-R cells. This phenolic compound combined with 5-FU exerted synergistic inhibitory effect on cell viability. This combination enhanced the apoptosis and induced cell cycle arrest of both chemo-resistant and sensitive cells through impacting the expression levels of different cellular effectors. Kaempferol also blocked the production of reactive oxygen species (ROS) and modulated the expression of JAK/STAT3, MAPK, PI3K/AKT and NF-κB. In silico docking analysis suggested that the potent anti-tumoral effect of Kaempferol, compared to its two analogs (Kaempferol 3-O-glucoside and Kampferol 3-O-rutinoside), can be explained by the absence of glucosyl groups. Overall, our data propose Kaempferol as a potential chemotherapeutic agent to be used alone or in combination with 5-FU to overcome colon cancer drug resistance.

Modeling and Docking Studies of Toll Like Receptor 7 From Homo Sapiens with Biosynthetic Compounds Rutin and Kaempferol

Modeling and Docking Studies of Toll Like Receptor 7 From Homo Sapiens with Biosynthetic Compounds Rutin and Kaempferol

A DFT study of molecular structure and 1H NMR, IR, and UV‐Vis spectrum of Zn(II)‐kaempferol complexes: A metal‐flavonoid complex showing enhanced anticancer activity

The polyphenol compound Kaempferol, a relevant member of the class of flavonoids, is a good example where coordination to Zn(II) ion was found to improve the anticancer effects compared to the free ligand. Determination of the metal‐complex molecular structure (and binding sites on Kaempferol) in the liquid phase is fundamental for an understanding of biological activities. Experimental UV‐Vis and EPR data only provide indirect evidence or limited structural information. Therefore, theoretical study of structural and spectroscopic properties of the metal‐polyphenol complex, using computational quantum chemistry methods, is certainly relevant as starting point for the investigation of mechanism of action at a molecular level. In this article, we used the density functional theory (DFT) methodology to predict the molecular structure of [Zn(Kaempferol)(H2O)n]+ and [Zn(Kaempferol)2(H2O)n] complexes (n = 0, 2, or 4) and B‐ring nonplanar conformation of flavonoid using as strategy the best match between theoretical and experimental 1H NMR, IR, and UV‐Vis spectroscopic data in solution. These are valuable information for further studies involving structure‐activity relationship.