RESUMEN
Acanthamoeba castellanii is an opportunistic free-living amoeba (FLA) pathogen which can cause fatal central nervous system (CNS) infection, granulomatous amoebic encephalitis (GAE) and potentially blinding ocular infection, Acanthamoeba keratitis (AK). Acanthamoeba species remain a challenging protist to treat due to the unavailability of safe and effective therapeutic drugs and their ability to protect themselves in the cyst stage. Natural products and their secondary metabolites play a pivotal role in drug discovery against various pathogenic microorganisms. In the present study, the ethyl acetate extract of Myristica cinnamomea King fruit was evaluated against A. castellanii (ATCC 50492), showing an IC50 of 45.102 ± 4.62 µg/mL. Previously, the bio-guided fractionation of the extract resulted in the identification of three active compounds, namely Malabaricones (A-C). The isolated and thoroughly characterized acylphenols were evaluated for their anti-amoebic activity against A. castellanii for the first time. Among tested compounds, Malabaricone B (IC50 of 101.31 ± 17.41 µM) and Malabaricone C (IC50 of 49.95 ± 6.33 µM) showed potent anti-amoebic activity against A. castellanii trophozoites and reduced their viability up-to 75 and 80 %, respectively. Moreover, both extract and Malabaricones also significantly (p < 0.05) inhibit the encystation and excystation of A. castellanii, while showed minimal toxicity against human keratinocyte cells (HaCaT cells) at lower tested concentrations. Following that, the explanation of the possible mechanism of action of purified compounds were assessed by detection of the state of chromatin. Hoechst/PI 33342 double staining showed that necrotic cell death occurred in A. castellanii trophozoites after 8 h treatment of Malabaricones (A-C). These findings demonstrate that Malabaricones B and C could serve as promising therapeutic options against A. castellanii infections.
Asunto(s)
Queratitis por Acanthamoeba , Acanthamoeba castellanii , Amebiasis , Amebicidas , Myristica , Animales , Humanos , Amebicidas/farmacología , Frutas , Amebiasis/tratamiento farmacológico , TrofozoítosRESUMEN
Studies have been conducted over the last decade to identify secondary metabolites from plants, in particular those from the class of alkaloids, for the development of new anti-Alzheimer's disease (AD) drugs. The genus Alseodaphne, comprising a wide range of alkaloids, is a promising source for the discovery of new cholinesterase inhibitors, the first-line treatment for AD. With regard to this, a phytochemical investigation of the dichloromethane extract of the bark of A. pendulifolia Gamb. was conducted. Repeated column chromatography and preparative thin-layer chromatography led to the isolation of a new bisbenzylisoquinoline alkaloid, N-methyl costaricine (1), together with costaricine (2), hernagine (3), N-methyl hernagine (4), corydine (5), and oxohernagine (6). Their structures were elucidated by the 1D- and 2D-NMR techniques and LCMS-IT-TOF analysis. Compounds 1 and 2 were more-potent BChE inhibitors than galantamine with IC50 values of 3.51 ± 0.80 µM and 2.90 ± 0.56 µM, respectively. The Lineweaver-Burk plots of compounds 1 and 2 indicated they were mixed-mode inhibitors. Compounds 1 and 2 have the potential to be employed as lead compounds for the development of new drugs or medicinal supplements to treat AD.
Asunto(s)
Alcaloides , Bencilisoquinolinas , Lauraceae , Inhibidores de la Colinesterasa/farmacología , Inhibidores de la Colinesterasa/uso terapéutico , Inhibidores de la Colinesterasa/química , Butirilcolinesterasa/metabolismo , Alcaloides/farmacología , Alcaloides/química , Extractos Vegetales/farmacología , Extractos Vegetales/química , Lauraceae/química , Acetilcolinesterasa/metabolismoRESUMEN
The genus Myristica is a medicinally important genus belonging to the Myristicaceae. Traditional medicinal systems in Asia have employed plants from the genus Myristica to treat a variety of ailments. Acylphenols and dimeric acylphenols are a rare group of secondary metabolites, which, to date, have only been identified in the Myristicaceae, in particular, in the genus Myristica. The aim of the review would be to provide scientific evidence that the medicinal properties of the genus Myristica could be attributed to the acylphenols and dimeric acylphenols present in the various parts of its plants and highlight the potential in the development of the acylphenols and dimeric acylphenols as pharmaceutical products. SciFinder-n, Web of Science, Scopus, ScienceDirect, and PubMed were used to conduct the literature search between 2013-2022 on the phytochemistry and the pharmacology of acylphenols and dimeric acylphenols from the genus Myristica. The review discusses the distribution of the 25 acylphenols and dimeric acylphenols within the genus Myristica, their extraction, isolation, and characterization from the respective Myristica species, the structural similarities and differences within each group and between the different groups of the acylphenols and dimeric acylphenols, and their in vitro pharmacological activities.
RESUMEN
Over the years, labdane diterpenes, norlabdane diterpenes, and bis-labdanic diterpenes with cytotoxic activities have been identified across various families in the plant kingdom including the Zingiberaceae. The present review discusses the distribution of these labdane-type diterpenes within the Zingiberaceae; their extraction, isolation, and characterization from the respective Zingiberaceae species; the structural similarities and differences within each group and between the different groups of the labdane-type diterpenes; and their cytotoxic activities against breast, cervical, liver, colorectal, pancreatic, lung and prostate cancer cell lines. The review will also provide insight into how the cytotoxic activities of the labdane-type diterpenes are influenced by their structural features.
RESUMEN
The use of antidiabetic agents which control glycemic levels in the blood and simultaneously inhibit oxidative stress is an important strategy in the prevention of Diabetes Mellitus and its complications. In our previous study, malabaricone C (3) and its dimer, giganteone A (5) exhibited significant DPPH free radical scavenging activities which were lower than the activity of the positive control, ascorbic acid. These compounds were evaluated for their α-glucosidase inhibitory activities at different concentrations (0.02-2.5 mM) in the present study. Compounds 3 (IC50 59.61 µM) and 5 (IC50 39.52 µM) were identified as active alpha-glucosidase inhibitors, each respectively being 24 and 37 folds more potent than the standard inhibitor, acarbose. Based on the molecular docking studies, compounds 3 and 5 docked into the active site of the α-glucosidase enzyme, forming mainly hydrogen bonds in the active site.
Asunto(s)
Diabetes Mellitus , Inhibidores de Glicósido Hidrolasas , Compuestos de Bifenilo , Diabetes Mellitus/tratamiento farmacológico , Inhibidores de Glicósido Hidrolasas/química , Inhibidores de Glicósido Hidrolasas/farmacología , Humanos , Hipoglucemiantes/química , Hipoglucemiantes/farmacología , Hipoglucemiantes/uso terapéutico , Simulación del Acoplamiento Molecular , Resorcinoles , Relación Estructura-Actividad , alfa-Glucosidasas/metabolismoRESUMEN
The oil palm tree (Elaeis guineensis Jacq.) originates from West and Central Africa, and it is cultivated in Malaysia for its oil-producing fruits. Malaysia is the world's second largest palm oil producer and the world's largest exporter to date. Consequently, the Malaysian oil palm industry constantly generates a huge amount of biomass with the major contributor being the leaves. A large percentage of these leaves remain underutilized, making them a promising source of raw materials that can be converted into value-added products. The present review summarizes and discusses the flavonoid composition, total phenolic and flavonoid content, and the in vitro and in vivo pharmacological properties exhibited by the extracts of the leaves of E. guineensis. The purpose of this systematic review is to highlight the potential of valorizing the leaf extracts of the oil palm tree as pharmaceutical and cosmeceutical agents.
RESUMEN
The interaction between natural occurring inhibitors and targeted membrane proteins could be an alternative medicinal strategy for the treatment of metabolic syndrome, notably, obesity. In this study, we identified malabaricones A-C and E (1-4) isolated from the fruits of Myristica cinnamomea King as natural inhibitors for sphingomyelin synthase (SMS), a membrane protein responsible for sphingolipid biosynthesis. Having the most promising inhibition, oral administration of compound 3 exhibited multiple efficacies in reducing weight gain, improving glucose tolerance, and reducing hepatic steatosis in high fat diet-induced obesity mice models. Liver lipid analysis revealed a crucial link between the SMS activities of compound 3 and its lipid metabolism in vitro and in vivo. The nontoxic nature of compound 3 makes it a suitable candidate in search of drugs which can be employed in the treatment and prevention of obesity.
RESUMEN
The inhibition of carbohydrate-hydrolyzing enzymes in human digestive organs is crucial in controlling blood sugar levels, which is important in treating typeâ 2 diabetes. In the current study, pahangensin A (1), a bis-labdanic diterpene characterized previously in the rhizomes of Alpinia pahangensis Ridl., was identified as an active dual inhibitor for α-amylase (IC50 =114.80â µm) and α-glucosidase (IC50 =153.87â µm). This is the first report on the dual α-amylase and α-glucosidase inhibitory activities of a bis-labdanic diterpene. The Lineweaver-Burk plots of compound 1 indicate that it is a mixed-type inhibitor with regard to both enzymes. Based on molecular docking studies, compound 1 docked in a non-active site of both enzymes. The dual inhibitory activity of compound 1 makes it a suitable natural alternative in the treatment of typeâ 2 diabetes.
Asunto(s)
Alpinia/química , Diterpenos/química , alfa-Amilasas/metabolismo , alfa-Glucosidasas/metabolismo , Alpinia/metabolismo , Sitios de Unión , Dominio Catalítico , Diterpenos/aislamiento & purificación , Diterpenos/metabolismo , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/metabolismo , Cinética , Simulación del Acoplamiento Molecular , Extractos Vegetales/química , alfa-Amilasas/antagonistas & inhibidores , alfa-Glucosidasas/químicaRESUMEN
The aim of the present study is to isolate bioactive compounds from the roots of Piper sarmentosum and examine the mechanism of action using human breast cancer cell line (MDA-MB-231). Bioassay guided-fractionation of methanolic extract led to the isolation of asaricin (1) and isoasarone (2). Asaricin (1) and isoasarone (2) had significant cytotoxicity towards MDA-MB-231. MCF-10A (human normal breast epithelial cells) cells are less sensitive than MDA-MB-231, but they respond to the treatment with the same unit of measurement. Both compounds increase reactive oxygen species (ROS), decrease mitochondrial membrane potential (MMP) and enhance cytochrome c release in treated MDA-MB-231 cells. Isoasarone (2) markedly elevated caspase -8 and -3/7 activities and caused a decline in nuclear NF-κB translocation, suggesting extrinsic, death receptor-linked apoptosis pathway. Quantitative PCR results of MDA-MB-231 treated with asaricin (1) and isoasarone (2) showed altered expression of Bcl-2: Bax level. The inhibitory potency of these isolates may support the therapeutic uses of these compounds in breast cancer.
Asunto(s)
Apoptosis/efectos de los fármacos , Mitocondrias/efectos de los fármacos , Fenilpropionatos/farmacología , Piper/química , Especies Reactivas de Oxígeno/metabolismo , Antineoplásicos Fitogénicos , Neoplasias de la Mama , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Femenino , Humanos , Mitocondrias/metabolismo , Estructura Molecular , Fenilpropionatos/químicaRESUMEN
A new acylphenol, malabaricone E (1) together with the known malabaricones A-C (2-4), maingayones A and B (5 and 6) and maingayic acid B (7) were isolated from the ethyl acetate extract of the fruits of Myristica cinnamomea King. Their structures were determined by 1D and 2D NMR techniques and LCMS-IT-TOF analysis. Compounds 3 (1.84±0.19 and 1.76±0.21µM, respectively) and 4 (1.94±0.27 and 2.80±0.49µM, respectively) were identified as dual inhibitors, with almost equal acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes inhibiting potentials. The Lineweaver-Burk plots of compounds 3 and 4 indicated that they were mixed-mode inhibitors. Based on the molecular docking studies, compounds 3 and 4 interacted with the peripheral anionic site (PAS), the catalytic triad and the oxyanion hole of the AChE. As for the BChE, while compound 3 interacted with the PAS, the catalytic triad and the oxyanion hole, compound 4 only interacted with the catalytic triad and the oxyanion hole.
Asunto(s)
Acetilcolinesterasa/metabolismo , Productos Biológicos/farmacología , Butirilcolinesterasa/metabolismo , Inhibidores de la Colinesterasa/farmacología , Myristicaceae/química , Animales , Productos Biológicos/química , Productos Biológicos/aislamiento & purificación , Inhibidores de la Colinesterasa/química , Inhibidores de la Colinesterasa/aislamiento & purificación , Relación Dosis-Respuesta a Droga , Humanos , Simulación del Acoplamiento Molecular , Estructura Molecular , Relación Estructura-ActividadRESUMEN
Giganteone E (1), a new dimeric acylphenol was isolated as a minor constituent from the bark of Myristica maxima Warb. The structure of 1 was established on the basis of 1D and 2D NMR techniques and LCMS-IT-TOF analysis. Malabaricones A-C (2-4), giganteones A and C (5 and 6), maingayones A and B (7 and 8), maingayic acid B (9) and ß-sitosteryl oleate (10) were also characterized in this plant for the first time. Compound 10 was identified for the first time in the Myristicaceae. Compounds 2 and 5 were active against human prostate cancer cell-lines, thus making this the first report on the prostate cancer inhibiting potential of acylphenols and dimeric acylphenols. Compounds 1, 4, 5, 7 and 8 exhibited potent DPPH free radical scavenging activity. This is the first report on their free radical scavenging capacity.
Asunto(s)
Myristicaceae/química , Fenoles/farmacología , Antineoplásicos Fitogénicos/aislamiento & purificación , Antineoplásicos Fitogénicos/farmacología , Línea Celular Tumoral/efectos de los fármacos , Depuradores de Radicales Libres/aislamiento & purificación , Depuradores de Radicales Libres/farmacología , Humanos , Masculino , Estructura Molecular , Fenoles/aislamiento & purificación , Neoplasias de la Próstata/patología , Resorcinoles/aislamiento & purificación , Resorcinoles/farmacologíaRESUMEN
OBJECTIVE: To study antiplasmodial and antioxidant activities of the isolation of alkaloids from the active dichloromethane extract of Alseodaphne corneri. METHODS: Phytochemical studies of the crude extract led to the isolation of six alkaloids using recycle high performance liquid chromatography and preparative thin layer chromatography. The antiplasmodial activity of the isolated compounds was evaluated using the histidine-rich protein II assay. The isolated alkaloids were also tested for their antioxidant activity using three different assays; DPPH, ferric reducing ability of plasma and metal chelating assays. RESULTS: Malaria infection caused the formation of free radicals which subsequently led to oxidative stress and apoptosis. The antioxidant properties of the alkaloids under investigation revealed that in addition to the antiplasmodial activity, the alkaloids could also prevent oxidative stress. (+)-laurotetanine and (+)-norstephasubine exhibited strong antiplasmodial activities with IC50 values of 0.189 and 0.116 µM, respectively. CONCLUSIONS: Interestingly, the two most potent compounds that exhibit antiplasmodial activity also exhibit good antioxidant activities. The crude dichloromethane extract and the isolated compounds exert substantial antiplasmodial and antioxidative activities which in turn suppress oxidative stress and cause less damage to the host.
RESUMEN
Malabaricones A-C (1-3) and giganteone A (4) were isolated from the bark of Myristica cinnamomea King. Their structures were elucidated and characterized by means of NMR and MS spectral analyses. These isolates were evaluated for their anti-quorum sensing activity using quorum sensing biosensors, namely Escherichia coli [pSB401] and Escherichia coli [pSB1075], whereby the potential of giganteone A (4) as a suitable anti-quorum sensing agent was demonstrated.
Asunto(s)
Antibacterianos/farmacología , Técnicas Biosensibles , Compuestos de Bifenilo/farmacología , Percepción de Quorum/efectos de los fármacos , Resorcinoles/farmacología , Antibacterianos/química , Antibacterianos/aislamiento & purificación , Compuestos de Bifenilo/química , Escherichia coli/efectos de los fármacos , Escherichia coli/patogenicidad , Humanos , Myristicaceae/química , Pseudomonas aeruginosa/efectos de los fármacos , Pseudomonas aeruginosa/patogenicidad , Resorcinoles/química , Resorcinoles/aislamiento & purificaciónRESUMEN
The mammalian hyaluronidase degrades hyaluronic acid by the cleavage of the ß-1,4-glycosidic bond furnishing a tetrasaccharide molecule as the main product which is a highly angiogenic and potent inducer of inflammatory cytokines. Ursolic acid 1, isolated from Prismatomeris tetrandra, was identified as having the potential to develop inhibitors of hyaluronidase. A series of ursolic acid analogues were either synthesized via structure modification of ursolic acid 1 or commercially obtained. The evaluation of the inhibitory activity of these compounds on the hyaluronidase enzyme was conducted. Several structural, topological and quantum chemical descriptors for these compounds were calculated using semi empirical quantum chemical methods. A quantitative structure activity relationship study (QSAR) was performed to correlate these descriptors with the hyaluronidase inhibitory activity. The statistical characteristics provided by the best multi linear model (BML) (R² = 0.9717, R²cv = 0.9506) indicated satisfactory stability and predictive ability of the developed model. The in silico molecular docking study which was used to determine the binding interactions revealed that the ursolic acid analog 22 had a strong affinity towards human hyaluronidase.
Asunto(s)
Histona Acetiltransferasas/antagonistas & inhibidores , Hialuronoglucosaminidasa/antagonistas & inhibidores , Triterpenos Pentacíclicos/síntesis química , Triterpenos Pentacíclicos/farmacología , Rubiaceae/química , Antígenos de Neoplasias/química , Antígenos de Neoplasias/metabolismo , Simulación por Computador , Histona Acetiltransferasas/química , Histona Acetiltransferasas/metabolismo , Humanos , Hialuronoglucosaminidasa/química , Hialuronoglucosaminidasa/metabolismo , Modelos Moleculares , Simulación del Acoplamiento Molecular , Triterpenos Pentacíclicos/química , Extractos Vegetales/química , Relación Estructura-Actividad Cuantitativa , Triterpenos/química , Triterpenos/aislamiento & purificación , Triterpenos/farmacología , Ácido UrsólicoRESUMEN
The UV-vis spectra of isocorydine 1, norisocorydine 2 and boldine 3 were studied in 2% v/v acetonitrile, at constant ionic strength (0.1 M NaCl, 35 degree Celsius). The pK(a) values of isocorydine 1 and norisocorydine 2 were 11.75 and 12.07, respectively. Boldine 3 gave a pK(a) value of 9.16 and 10.44. All of the alkaloids 1-3 were stable at physiological pH; thereby all of them will not ionize, thus permitting the basic nitrogen to be protonated and accumulated within the acidic food vacuole of Plasmodium via pH trapping. Subsequently, acidic food vacuoles that have been neutralized by alkaloids would result in enhancement of the antiplasmodial activity. The alkaloids showed antiplasmodial activity against Plasmodium falciparum and antioxidant activities; DPPH radical scavenging, metal chelating and ferric reducing power. The antioxidant properties of the alkaloids under investigation revealed that in addition to the antiplasmodial activity, the alkaloids can also prevent oxidative damage. It can be prevented by binding free heme and neutralizing the electrons produced during the Plasmodium falciparum mediated haemoglobin destruction in the host. Slightly basic properties of the aforementioned alkaloids, along with their antioxidant activities, are advantageous in improving the suppression of malaria infection that cause less damage to the host.
Asunto(s)
Alcaloides/farmacología , Antimaláricos/farmacología , Malaria/tratamiento farmacológico , Extractos Vegetales/farmacología , Plasmodium falciparum/efectos de los fármacos , Alcaloides/química , Alcaloides/aislamiento & purificación , Antimaláricos/química , Antimaláricos/aislamiento & purificación , Antioxidantes/química , Antioxidantes/aislamiento & purificación , Antioxidantes/farmacología , Aporfinas/química , Aporfinas/farmacología , Humanos , Lauraceae/química , Malaria/parasitología , Malaria/patología , Estructura Molecular , Extractos Vegetales/química , Plasmodium falciparum/patogenicidadRESUMEN
A dimeric acylphenol and a potent α-glucosidase inhibitor, giganteone D (IC50 5.05µM), was isolated and characterized from the bark of Myristica cinnamomea King. The bark also yielded an acylphenol with an unprecedented skeleton for which the name cinnamomeone A (IC50 358.80µM) was proposed. Their structures were established by means of NMR and MS spectrometric analyses. The Lineweaver-Burk plot of giganteone D indicated that it was a mixed-type inhibitor. This is the first report on the α-glucosidase inhibiting potential of acylphenols.
Asunto(s)
Inhibidores de Glicósido Hidrolasas/aislamiento & purificación , Inhibidores de Glicósido Hidrolasas/farmacología , Hipoglucemiantes/aislamiento & purificación , Hipoglucemiantes/farmacología , Myristicaceae/química , alfa-Glucosidasas/efectos de los fármacos , Inhibidores de Glicósido Hidrolasas/química , Hipoglucemiantes/química , Resonancia Magnética Nuclear Biomolecular , Corteza de la Planta/químicaRESUMEN
The essential oils obtained by hydrodistillation of the unripe and ripe fruits of Alpinia mutica Roxb. and Alpinia latilabris Ridl. were analysed by capillary GC and GC-MS. The oils were principally monoterpenic in nature. The unripe and ripe fruit oils of A. mutica were characterized by camphor (21.0% and 15.8%), camphene (16.6% and 10.2%), ß-pinene (8.6% and 13.5%), and trans,trans-farnesol (8.0% and 11.2%), respectively. The oils of the unripe and ripe fruits were moderately active against Staphylococcus aureus, Bacillus subtilis, Trichophyton mentagrophytes, and Trichophyton rubrum. 1,8-Cineole (34.2% and 35.9%) and ß-pinene (20.2% and 19.0%) were the two most abundant components in the unripe and ripe fruit oils of A. latilabris. The oil of the unripe fruits elicits moderate activity against Staphylococcus aureus and Trichophyton mentagrophytes while Candida glabrata was moderately sensitive to the oil of the ripe fruits.
Asunto(s)
Alpinia/química , Antiinfecciosos/química , Antiinfecciosos/farmacología , Aceites Volátiles/química , Aceites Volátiles/farmacología , Antiinfecciosos/aislamiento & purificación , Malasia , Pruebas de Sensibilidad Microbiana , Aceites Volátiles/aislamiento & purificación , Componentes Aéreos de las Plantas/genéticaRESUMEN
The rhizomes of Alpinia pahangensis yielded a new bis-labdanic diterpene for which the name pahangensin C (1) was proposed along with twelve known analogues (2-13). The structure of 1 was elucidated via spectroscopic methods including 1D and 2D NMR techniques and LCMS-IT-TOF analysis. Compounds 2 and 12 were isolated for the first time from the genus Alpinia. This is the second occurrence of compounds 2 and 12 in the Zingiberaceae family. Selected analogues exhibited moderate to strong inhibitory activity against Staphylococcus aureus and Bacillus cereus.
Asunto(s)
Alpinia/química , Bacillus cereus/efectos de los fármacos , Diterpenos/aislamiento & purificación , Extractos Vegetales/aislamiento & purificación , Rizoma/química , Staphylococcus aureus/efectos de los fármacos , Antibacterianos , Diterpenos/química , Diterpenos/farmacología , Espectroscopía de Resonancia Magnética , Malasia , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Extractos Vegetales/química , Extractos Vegetales/farmacologíaRESUMEN
The rhizomes of Alpinia pahangensis Ridley yielded a new bis-labdanic diterpene for which the name pahangensin A (1) was proposed along with a new labdane diterpene, pahangensin B (2). Their structures were elucidated by spectroscopic methods including, 1D and 2D NMR techniques and LCMS-IT-TOF analysis. Pahangensin A (1) was found to be an antibacterial agent against Staphylococcus aureus, Bacillus cereus and Bacillus subtilis with MIC values less than 100 µg/mL, respectively. Pahangensin B (2) exhibited antibacterial activity (MIC <100 µg/mL) against B. cereus.
Asunto(s)
Alpinia/química , Antibacterianos/química , Diterpenos/química , Rizoma/química , Antibacterianos/análisis , Antibacterianos/farmacología , Diterpenos/farmacología , EstereoisomerismoRESUMEN
The rhizomes of Zingiber spectabile yielded a new dimeric flavonol glycoside for which the name kaempferol-3-O-(4â³-O-acetyl)-α-L-rhamnopyranoside-(I-6,II-8)-kaempferol-3-O-(4â³-O-acetyl)-α-L-rhamnopyranoside; spectaflavoside A (1) was proposed, along with kaempferol and its four acetylrhamnosides (2-6), demethoxycurcumin (7) and curcumin (8). The structure of spectaflavoside A was elucidated by spectroscopic methods including, 1D and 2D NMR techniques. This is the first report on the occurrence of a dimeric flavonol glycoside in the Zingiberaceae and the second in nature. Spectaflavoside A was found to be a potent iron chelating agent.