Displaying publications 1 - 20 of 37 in total

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  1. Antioxidant and α-glucosidase inhibitory activities of 40 tropical juices from Malaysia and identification of phenolics from the bioactive fruit juices of Barringtonia racemosa and Phyllanthus acidus
    Sulaiman SF, Ooi KL
    J Agric Food Chem, 2014 Oct 1;62(39):9576-85.
    PMID: 25198055 DOI: 10.1021/jf502912t
    The present study compared pH, total soluble solids, vitamin C, and total phenolic contents, antioxidant activities, and α-glucosidase inhibitory activities of 40 fresh juices. The juice of Baccaurea polyneura showed the highest yield (74.17 ± 1.44%) and total soluble solids (32.83 ± 0.27 °Brix). The highest and lowest pH values were respectively measured from the juices of Dimocarpus longan (6.87 ± 0.01) and Averrhoa bilimbi (1.67 ± 0.67). The juice of Psidium guajava gave the highest total phenolic (857.24 ± 12.65 μg GAE/g sample) and vitamin C contents (590.31 ± 7.44 μg AAE/g sample). The juice of Phyllanthus acidus with moderate contents of total phenolics and vitamin C was found to exhibit the greatest scavenging (613.71 ± 2.59 μg VCEAC/g sample), reducing (2784.89 ± 3.93 μg TEAC/g sample), and α-glucosidase inhibitory activities (95.37 ± 0.15%). The juice of Barringtonia racemosa was ranked second in the activities and total phenolic content. Gallic and ellagic acids, which were quantified as the major phenolics of the respective juices, are suggested to be the main contributors to the antioxidant activities. The α-glucosidase inhibitory activity of the juices could be derived from myricetin and quercetin (that were previously reported as potent α-glucosidase inhibitors) in the hydrolyzed juice extracts. The juice of Syzygium samarangense, which was found to be highest in metal chelating activity (82.28 ± 0.10%), also was found to have these phenolics.
  2. Antioxidant and α-glucosidase inhibitory activities of cucurbit fruit vegetables and identification of active and major constituents from phenolic-rich extracts of Lagenaria siceraria and Sechium edule
    Sulaiman SF, Ooi KL, Supriatno
    J Agric Food Chem, 2013 Oct 23;61(42):10080-90.
    PMID: 24059845 DOI: 10.1021/jf4031037
    Antioxidant and α-glucosidase activities and total phenolic contents (TPC) in sequential extracts of dried pulps from seven cucurbit fruit vegetables were determined for the first time. The highest TPC and metal chelating activity were obtained from the chloroform extracts of Luffa acutangula (28.04 ± 0.37 mg GAE/g extract) and Benincasa hispida (EC50 = 0.44 ± 0.03 mg/mL), respectively. The ethyl acetate extract of Sechium edule showed the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity (951.73 ± 29.14 mM TE/g extract). The highest reducing and anti-α-glucosidase activities were shown by the methanol and ethyl acetate extracts of Momordica charantia (692.56 ± 43.38 mM AscAE/g extract; 66.64 ± 2.94%, respectively). The highest correlation (r = 0.99) was observed between the TPC and DPPH values of S. edule. Although caffeic acid was quantified as the major constituent in the methanol extract of Lagenaria siceraria , isoquercetin was found to be the main contributor to the activities. Gallic acid was identified as both the main and most active antioxidant constituent in the ethyl acetate extract of S. edule.
  3. Polyphenolic and vitamin C contents and antioxidant activities of aqueous extracts from mature-green and ripe fruit fleshes of Mangifera sp
    Sulaiman SF, Ooi KL
    J Agric Food Chem, 2012 Nov 28;60(47):11832-8.
    PMID: 23136968 DOI: 10.1021/jf303736h
    Mature-green and ripe fleshes from 12 samples of Mangifera were selected for this study. The mature-green fleshes were found to have higher vitamin C contents than the ripe fleshes. However, not all higher total or individual phenolic contents were measured from the mature-green fleshes. The highest contents of vitamin C and total phenolics were respectively measured from the aqueous extracts of mature-green (255.86 ± 12.98 μg AAE/g sample) and ripe (142.57 ± 0.38 μg GAE/g sample) fleshes of M. petandra cv. Pauh. Gallic acid and mangiferin were detected in all aqueous extracts. The extracts of the mature-green flesh of M. indica cv. Chokanan and the ripe flesh of M. indica cv. Siku Raja, respectively, exhibited the greatest 1,1-diphenyl-2-picrylhydrazyl radical (DPPH)-scavenging activity (408.21 ± 5.37 μg TE/g sample) and metal chelating activity (93.68 ± 0.74%). The combined or potentiation effects of the moderate vitamin C, gallic acid, and mangiferin contents in both extracts may be responsible for the activities. The highest mangiferin content (31.72 ± 2.57 μg/g sample) in the mature-green M. caesia (Binjai) could be the major contributor to its highest FRAP activity (868.29 ± 2.71 μg TE/g sample). This paper reports apparently the first comparative study highlighting the antioxidant activities of these fruit fleshes.
  4. Investigation of optimum roasting conditions to obtain possible health benefit supplement, antioxidants from coffee beans
    Sulaiman SF, Moon JK, Shibamoto T
    J Diet Suppl, 2011 Sep;8(3):293-310.
    PMID: 22432728 DOI: 10.3109/19390211.2011.593618
    In order to investigate the role of roasting conditions in antioxidant formation, methanol and hot water extracts from Robusta coffee beans roasted for various lengths of time and at various temperatures were analyzed for total phenolic acid, chlorogenic acid, and caffeine content, as well as for their antioxidant activities using 1,1-diphenyl-2-picryhydrazyl (DPPH), thiobarbituric acid (TBA), and malonaldehyde/gas chromatography (MA/GC) assays. The amount of total phenolics in methanol extracts decreased linearly over the roasting temperature from 63.51 ± 0.77 mg chlorogenic acid equivalent (CAE)/g coffee beans (roasted at 200°C) to 42.56 ± 0.33 mg CAE/g coffee beans (roasted at 240°C). The total chlorogenic acid content decreased when the roasting time was increased from 78.33 ± 1.41 mg/g (green coffee beans) to 4.31 ± 0.23 mg/g (roasted for 16 min at 250°C). All methanol extracts from roasted coffee beans possessed over 90% antioxidant activities in the DPPH assay. The antioxidant activity of methanol extracts ranged from 41.38 ± 1.77% (roasted at 250°C for 10 min) to 98.20 ± 1.49% (roasted at 230°C for 16 min) as tested by the TBA assay. The antioxidant activity of methanol extracts of green coffee beans and roasted coffee beans ranged from 93.01% (green coffee beans) to 98.62 ± 1.32% (roasted at 250°C for 14 min) in the MA/GC assays. All hot water extracts exhibited moderate pro-oxidant activities in TBA and MA/GC assays. The results indicated that roasting conditions of coffee beans play an important role in the formation of antioxidants in brewed coffee, which can be dietary supplements having beneficial effect to human health.
  5. Physalin F from Physalis minima L. triggers apoptosis-based cytotoxic mechanism in T-47D cells through the activation caspase-3- and c-myc-dependent pathways
    Ooi KL, Muhammad TS, Sulaiman SF
    J Ethnopharmacol, 2013 Oct 28;150(1):382-8.
    PMID: 24051023 DOI: 10.1016/j.jep.2013.09.014
    Physalin F (a secosteroid derivative), is well recognized as a potent anticancer compound from Physalis minima L., a plant that is traditionally used to treat cancer. However, the exact molecular anticancer mechanism remains to be elucidated.
  6. In vitro ovicidal and larvicidal activity of methanolic leaf extract of Manihot esculenta (cassava) on susceptible and resistant strains of Trichostrongylus colubriformis
    Al-Rofaai A, Rahman WA, Sulaiman SF, Yahaya ZS
    Vet Parasitol, 2012 Nov 23;190(1-2):127-35.
    PMID: 22749290 DOI: 10.1016/j.vetpar.2012.05.028
    This study aimed to represent the first report of the ovicidal and larvicidal activity of the methanolic leaf extract of Manihot esculenta (cassava) against eggs and larvae of susceptible and resistant strains of Trichostrongylus colubriformis. As well as, to determine the total tannin compounds, antioxidant activity and toxicity of the extract. The egg hatch test was used to evaluate ovicidal activity against unembryonated eggs, whereas larval feeding inhibition assay and MTT-formazan assay were used to evaluate larvicidal activity against first (L(1)) and infective (L(3)) larvae, respectively. The results showed no significant differences were detected between the sensitivities of susceptible and resistant strains of T. colubriformis to the extract. Eggs, L(1) and L(3) were significantly affected (P<0.001) compared with negative control, and L(1) were more sensitive than the eggs and L(3). The total tannin compounds were investigated using tannin quantification assay and determined by 254.44 TAE/mg. The antioxidant activity was evaluated using the DPPH radical scavenging assay and the median inhibition concentration (IC(50)) was determined by 2.638 mg/ml. Acute oral toxicity at dose of 5,000 mg/kg, and sub-chronic oral toxicity at 500 and 1,000 mg/kg of the extract were observed in male and female Sprague-Dawley (SD) rats. The acute oral toxicity revealed that the median lethal dose (LD(50)) of methanolic extract of cassava leaves on SD rats was greater than 5,000 mg/kg, whereas the sub-chronic oral toxicity did not show observed adverse effects at 500 and 1,000 mg/kg per day for 28 days. In conclusion, the methanolic extract of cassava leaves has direct ovicidal and larvicidal activity against T. colubriformis strains with a safety margin for animals, and it may be potentially utilized as a source of natural antioxidants.
  7. Inhibition of Klebsiella pneumoniae ATCC 13883 cells by hexane extract of Halimeda discoidea (Decaisne) and the identification of its potential bioactive compounds
    Supardy NA, Ibrahim D, Sulaiman SF, Zakaria NA
    J Microbiol Biotechnol, 2012 Jun;22(6):872-81.
    PMID: 22573167
    The inhibitory effect of the Klebsiella pneumoniae ATCC 13883 strain caused by the hexane extract of Halimeda discoidea (Nor Afifah et al., 2010) was further evaluated by means of the microscopy view and its growth curves. The morphological changes of the K. pneumoniae ATCC 13883 cells were observed under the scanning electron microscope (SEM) and transmission electron microscope (TEM) after they were treated at minimum inhibitory concentration (MIC; 0.50 mg/ml) (Nor Afifah et al., 2010) for 12, 24, and 36 h. The results showed the severity of the morphological deteriorations experienced by the treated cells. The killing curve assay was performed for 48 h at three different extract concentrations (1/2 MIC, MIC, and 2 MIC). An increase in the extract concentration of up to 2 MIC value did significantly reduce the number of cells by approximately 1.9 log10, as compared with the control. Identification of the potential compounds of the extract responsible for the antibacterial activity was carried out through the gas chromatography-mass spectrum (GCMS) analysis of the active subfraction, and the compound E-15-heptadecenal was identified and suggested as the most potential antibacterial compound of this extract. The subsequent cellular degenerations showed by the data might well explain the inhibitory mechanisms of the suggested antibacterial compound. All of these inhibitory effects have further proven the presence of an antibacterial compound within H. discoidea that can inhibit the growth of K. pneumoniae ATCC 13883.
  8. In vitro activity of neem (Azadirachta indica) and cassava (Manihot esculenta) on three pre-parasitic stages of susceptible and resistant strains of Teladorsagia (Ostertagia) circumcincta
    Al-Rofaai A, Rahman WA, Sulaiman SF, Yahaya ZS
    Vet Parasitol, 2012 Aug 13;188(1-2):85-92.
    PMID: 22455724 DOI: 10.1016/j.vetpar.2012.03.002
    Anthelmintic resistance of gastrointestinal nematodes is considered as one of the main limiting factors causing significant economic losses to the small ruminant industry. The anthelmintic properties of some plants are among the suggested alternative solutions to control these parasitic worms. The present study investigated the anthelmintic activity of neem (Azadirachta indica) and cassava (Manihot esculenta) leaf extracts against the susceptible and resistant strains of one of the most important nematodes in small ruminants, Teladorsagia (Ostertagia) circumcincta. Three different in vitro tests: egg hatch test, larval development assay, and larval paralysis assay were used to determine the efficiency of neem and cassava extracts on three pre-parasitic stages of T. circumcincta. The LC(50) was determined for the most potent extract in each plant as well as the phytochemical tests, total tannin quantification and cytotoxicity on peripheral blood mononuclear cells of goats. The results revealed a high anthelmintic activity of neem methanol extract (NME) and cassava methanol extract (CME) on both strains of T. circumcincta without significant differences between the strains. The first stage larvae were more sensitive with the lowest LC(50) at 7.15 mg/ml and 10.72 mg/ml for NME and CME, respectively, compared with 44.20mg/ml and 56.68 mg/ml on eggs and 24.91 mg/ml and 71.96 mg/ml on infective stage larvae.
  9. Cytotoxic and Apoptotic Effects of Ethyl Acetate Extract of Elephantopus mollis Kunth. in Human Liver Carcinoma HepG2 Cells Through Caspase-3 Activation
    Ooi KL, Tengku Muhammad TS, Lam LY, Sulaiman SF
    Integr Cancer Ther, 2014 May;13(3):NP1-9.
    PMID: 22336595 DOI: 10.1177/1534735411433203
    Previous cytotoxic (anticancer) evaluations ofElephantopus molliswere mainly focused on its elephantopin derivatives neglecting the combined effect of the phytochemicals in its traditionally used extracts. In this study, the cytotoxic mechanism of its extracts was investigated using methylene blue assay. The cytotoxic screening results revealed the ethyl acetate extract as the most potent extract by displaying prominent dose-dependent and time-dependent growth inhibitions in human liver carcinoma HepG2 cells with the lowest EC50value of 9.38 ± 0.43 µg/mL after 72 hours of treatment. Acute exposure of the HepG2 cells to the ethyl acetate extract produced a significant regulation of caspase-3 with the peak expression at 8 hours of treatment (P< .05). DNA fragmentation indicated by DeadEnd Apoptosis Detection System-labeled nuclei cells confirmed that the extract induced apoptotic cell death through caspase-3-dependent pathway in HepG2 cells.
  10. Cytotoxic, apoptotic and anti-α-glucosidase activities of 3,4-di-O-caffeoyl quinic acid, an antioxidant isolated from the polyphenolic-rich extract of Elephantopus mollis Kunth
    Ooi KL, Muhammad TS, Tan ML, Sulaiman SF
    J Ethnopharmacol, 2011 Jun 1;135(3):685-95.
    PMID: 21497647 DOI: 10.1016/j.jep.2011.04.001
    The decoction of the whole plant of Elephantopus mollis Kunth. is traditionally consumed to treat various free radical-mediated diseases including cancer and diabetes.
  11. Apoptotic effects of Physalis minima L. chloroform extract in human breast carcinoma T-47D cells mediated by c-myc-, p53-, and caspase-3-dependent pathways
    Ooi KL, Tengku Muhammad TS, Lim CH, Sulaiman SF
    Integr Cancer Ther, 2010 Mar;9(1):73-83.
    PMID: 20150224 DOI: 10.1177/1534735409356443
    The chloroform extract of Physalis minima produced a significant growth inhibition against human T-47D breast carcinoma cells as compared with other extracts with an EC(50) value of 3.8 microg/mL. An analysis of cell death mechanisms indicated that the extract elicited an apoptotic cell death. mRNA expression analysis revealed the coregulation of apoptotic genes, that is, c-myc , p53, and caspase-3. The c-myc was significantly induced by the chloroform extract at the earlier phase of treatment, followed by p53 and caspase-3. Biochemical assay and ultrastructural observation displayed typical apoptotic features in the treated cells, including DNA fragmentation, blebbing and convolution of cell membrane, clumping and margination of chromatin, and production of membrane-bound apoptotic bodies. The presence of different stages of apoptotic cell death and phosphatidylserine externalization were further reconfirmed by annexin V and propidium iodide staining. Thus, the results from this study strongly suggest that the chloroform extract of P. minima induced apoptotic cell death via p53-, caspase-3-, and c-myc-dependent pathways.
  12. Growth arrest and induction of apoptotic and non-apoptotic programmed cell death by, Physalis minima L. chloroform extract in human ovarian carcinoma Caov-3 cells
    Ooi KL, Muhammad TS, Sulaiman SF
    J Ethnopharmacol, 2010 Mar 2;128(1):92-9.
    PMID: 20045455 DOI: 10.1016/j.jep.2009.12.032
    The decoction of the whole plant of Physalis minima L. is traditionally consumed to treat cancer. Its anticancer property has been previously verified (using in vitro cytotoxicity assays) against NCI-H23 lung, CORL23 lung and MCF7 breast cancer cell lines but the mechanism underlying the anticancer potency towards ovarian carcinoma cells remain unclear.
  13. Growth arrest and non-apoptotic programmed cell death associated with the up-regulation of c-myc mRNA expression in T-47D breast tumor cells following exposure to Epipremnum pinnatum (L.) Engl. hexane extract
    Tan ML, Muhammad TS, Najimudin N, Sulaiman SF
    J Ethnopharmacol, 2005 Jan 15;96(3):375-83.
    PMID: 15619555
    Epipremnum pinnatum (L.) Engl. hexane extract produced a significant growth inhibition against T-47D breast carcinoma cells and analysis of cell death mechanisms indicated that the extract elicited a non-apoptotic programmed cell death. T-47D cells exposed to the extract at EC(50) concentration (72 h) for 24 h failed to demonstrate typical DNA fragmentation associated with apoptosis, as carried out using a modified TUNEL assay. In addition, acute exposure to the extract produced an insignificant regulation of caspase-3 and p53 mRNA expression but increased in the c-myc mRNA expression. Ultrastructural analysis using transmission electron microscope demonstrated distinct vacuolated cells, which strongly indicated a Type II non-apoptotic cell death although the changes in chromatin were also detected. The presence of non-apoptotic programmed cell death was then reconfirmed with annexin-V and propidium iodide staining. These findings suggested that up-regulation of c-myc mRNA expression may have contributed to the growth arrest and Type II non-apoptotic programmed cell death in the Epipremnum pinnatum (L.) Engl. hexane extract-treated T-47D cells.
  14. The influence of chemical composition of potent inhibitors in the hydrolyzed extracts of anti-hyperuricemic plants to their xanthine oxidase activities
    Ooi KL, Zakaria R, Tan ML, Sulaiman SF
    J Ethnopharmacol, 2021 Oct 05;278:114294.
    PMID: 34090914 DOI: 10.1016/j.jep.2021.114294
    ETHNOPHARMACOLOGICAL RELEVANCE: Anti-hyperuricemic plant parts that were selected for this study, are traditionally used to treat gout in Malaysia. Caffeic acid (a hydroxycinnamic acid), apigenin (a flavone), myricetin, quercetin and kaempferol (flavonols), were reported to act as potent xanthine oxidase inhibitors. These compounds can be found in some of the selected ethnomedicinal plants. However, there is still lack of published research works on the quantification of these inhibitors from these urate-lowering phytotherapies.

    AIMS OF THE STUDY: The compounds were quantified from 21 hydrolyzed extracts of the phytotherapies for gout. The activity-content contributions of the compounds to the potent extracts were determined.

    MATERIALS AND METHODS: The anti-hyperuricemic activities of the extracts and the compounds were determined using a xanthine oxidase inhibitory assay. Ultra-Performance Liquid Chromatography (UPLC) coupled with Photodiode Array Detector (PDA) was used to quantify the compounds in the extracts.

    RESULTS: The results revealed higher activity of the hydrolyzed extracts. The hydrolyzed extract of the flower bud of Syzygium aromaticum Merr. & L.M.Perry exhibited the highest activity (EC50 = 39.58 ± 0.10 μg/mL) due to the highest content of myricetin (42,297.55 ± 159.47 μg/g). The activity-content contribution of myricetin was 7.69%. Due to the highest activity of apigenin (EC50 = 3.27 ± 0.09 μg/mL), the highest contribution of this flavone (29.96%) to the hydrolyzed extract of Orthosiphon aristatus (Blume) Miq. was observed.

    CONCLUSION: The results revealed different contents and activities of xanthine oxidase inhibitors in the hydrolyzed extracts of anti-hyperuricemic plants can play a major role to influence the activity.

  15. The effect of flavonols in Anacardium occidentale L. leaf extracts on skin pathogenic microorganisms
    Hashim NS, Tan ML, Ooi KL, Sulaiman SF
    Nat Prod Res, 2023 Jun;37(12):2009-2012.
    PMID: 35997235 DOI: 10.1080/14786419.2022.2112038
    Cashew (Anacardium occidentale L.) leaf is traditionally used to treat skin infections. Although many flavonols have been identified from its leaf extract, their inhibitory effects on skin pathogens are not yet determined. The aims of this study were to determine the antimicrobial (against skin pathogenic microbes) and antioxidant activities of four flavonol glycosides from the crude extract and three flavonol aglycones from the hydrolyzed extract. The hydrolyzed extract was found to show higher activities than the crude extract. Myricetin showed the highest activity against all the tested bacteria and yeast with the lowest Minimum Inhibition Concentration (MIC) of 7.81 μg/mL on Corynebacterium minutissimum ATCC23348. Myricetin also exhibited good primary antioxidant activities with the effective concentration with 50% of activity (EC50) values ranged between 2.23 μg/mL and 6.40 μg/mL. The highest secondary antioxidant activity was indicated by myricetin-3-O-rhamnoside. Thus, myricetin can be considered as a bioactive compound of the hydrolyzed extract.
  16. Fulltext Cytotoxic Activities of Physalis minima L. Chloroform Extract on Human Lung Adenocarcinoma NCI-H23 Cell Lines by Induction of Apoptosis
    Leong OK, Muhammad TS, Sulaiman SF
    Evid Based Complement Alternat Med, 2011;2011:185064.
    PMID: 19541726 DOI: 10.1093/ecam/nep057
    Physalis minima L. is reputed for having anticancer property. In this study, the chloroform extract of this plant exhibited remarkable cytotoxic activities on NCI-H23 (human lung adenocarcinoma) cell line at dose- and time-dependent manners (after 24, 48 and 72 h of incubation). Analysis of cell-death mechanism demonstrated that the extract exerted apoptotic programed cell death in NCI-H23 cells with typical DNA fragmentation, which is a biochemical hallmark of apoptosis. Morphological observation using transmission electron microscope (TEM) also displayed apoptotic characteristics in the treated cells, including clumping and margination of chromatins, followed by convolution of the nuclear and budding of the cells to produce membrane-bound apoptotic bodies. Different stages of apoptotic programed cell death as well as phosphatidylserine externalization were confirmed using annexin V and propidium iodide staining. Furthermore, acute exposure to the extract produced a significant regulation of c-myc, caspase-3 and p53 mRNA expression in this cell line. Due to its apoptotic effect on NCI-H23 cells, it is strongly suggested that the extract could be further developed as an anticancer drug.
  17. Growth inhibition of human liver carcinoma HepG2 cells and α-glucosidase inhibitory activity of Murdannia bracteata (C.B. Clarke) Kuntze ex J.K. Morton extracts
    Ooi KL, Loh SI, Tan ML, Muhammad TS, Sulaiman SF
    J Ethnopharmacol, 2015 Mar 13;162:55-60.
    PMID: 25554642 DOI: 10.1016/j.jep.2014.12.030
    The juice of the entire fresh herb and infusion of dried sample of Murdannia bracteata are consumed to treat liver cancer and diabetes in Malaysia. However, no scientific evidence of these bioactivities has been reported.
  18. Fulltext Bioprospecting medicinal plants for antioxidant components
    Coulibaly AY, Hashim R, Sulaiman SF, Sulaiman O, Ang LZ, Ooi KL
    Asian Pac J Trop Med, 2014 Sep;7S1:S553-9.
    PMID: 25312183 DOI: 10.1016/S1995-7645(14)60289-3
    OBJECTIVE: To evaluate antioxidant activities of seven medicinal plant species and their fractions, and to identify their phenolic compounds.

    METHODS: Two extractions were processed and further fractionated by column chromatography to evaluate the concentration that inhibit 50% of 2,2'-azinobis (3-ethylbenzothiazoline-6-suslfonic acid, 1,1-diphenyl-2-picryl-hydrazyl radicals, and their ferric reducing antioxidant power. The identification of the fractions of phenolic compounds was done by ultra performance liquid chromatography.

    RESULTS: The aqueous-acetone extracts of Feretia apodanthera and Ozoroa insignis exhibited the highest antioxidant potentials comparable to those of the standard quercetin. Their subsequently silica gel column fractionation showed three most active fractions from which the major constituents quercetin, myricetin, kampferol, rutin and isoquercetin were identified.

    CONCLUSIONS: These plant species have potent antioxidant profiles and polyphenol compounds that may help to manage with radical related disease and aging.

  19. Fulltext Identification of small molecule inhibitors of p27(Kip1) ubiquitination by high-throughput screening
    Ooi LC, Watanabe N, Futamura Y, Sulaiman SF, Darah I, Osada H
    Cancer Sci, 2013 Nov;104(11):1461-7.
    PMID: 23910095 DOI: 10.1111/cas.12246
    Dysregulation of p27(Kip1) due to proteolysis that involves the ubiquitin ligase (SCF) complex with S-phase kinase-associated protein 2 (Skp2) as the substrate-recognition component (SCF(Skp2)) frequently results in tumorigenesis. In this report, we developed a high-throughput screening system to identify small-molecule inhibitors of p27(Kip1) degradation. This system was established by tagging Skp2 with fluorescent monomeric Azami Green (mAG) and CDK subunit 1 (Cks1) (mAGSkp2-Cks1) to bind to p27(Kip1) phosphopeptides. We identified two compounds that inhibited the interaction between mAGSkp2-Cks1 and p27(Kip1): linichlorin A and gentian violet. Further studies have shown that the compounds inhibit the ubiquitination of p27(Kip1) in vitro as well as p27(Kip1) degradation in HeLa cells. Notably, both compounds exhibited preferential antiproliferative activity against HeLa and tsFT210 cells compared with NIH3T3 cells and delayed the G1 phase progression in tsFT210 cells. Our approach indicates a potential strategy for restoring p27(Kip1) levels in human cancers.
  20. Fulltext Antioxidants in aqueous extract of Myristica fragrans (Houtt.) suppress mitosis and cyclophosphamide-induced chromosomal aberrations in Allium cepa L. cells
    Akinboro A, Mohamed KB, Asmawi MZ, Sulaiman SF, Sofiman OA
    J Zhejiang Univ Sci B, 2011 Nov;12(11):915-22.
    PMID: 22042656 DOI: 10.1631/jzus.B1000315
    In this study, freeze-dried water extract from the leaves of Myristica fragrans (Houtt.) was tested for mutagenic and antimutagenic potentials using the Allium cepa assay. Freeze-dried water extract alone and its combination with cyclophosphamide (CP) (50 mg/kg) were separately dissolved in tap water at 500, 1000, 2000, and 4000 mg/kg. Onions (A. cepa) were suspended in the solutions and controls for 48 h in the dark. Root tips were prepared for microscopic evaluation. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) free radicals' scavenging power of the extract was tested using butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) as standards. Water extract of Myristica fragrans scavenged free radicals better than BHA, but worse than BHT. The extract alone, as well as in combination with CP suppressed cell division, and induced chromosomal aberrations that were insignificantly different from the negative control (P ≤ 0.05). However, cytotoxic and mutagenic actions of CP were considerably suppressed. The observed effects on cell division and chromosomes of A. cepa may be principally connected to the antioxidant properties of the extract. The obtained results suggest mitodepressive and antimutagenic potentials of water extract of the leaves of M. fragrans as desirable properties of a promising anticancer agent.
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