Displaying publications 1 - 20 of 42 in total

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  1. Fulltext Syzygium campanulatum korth methanolic extract inhibits angiogenesis and tumor growth in nude mice
    Aisha AF, Ismail Z, Abu-Salah KM, Siddiqui JM, Ghafar G, Abdul Majid AM
    BMC Complement Altern Med, 2013;13:168.
    PMID: 23842450 DOI: 10.1186/1472-6882-13-168
    Syzygium campanulatum Korth (Myrtaceae) is an evergreen shrub rich in phenolics, flavonoid antioxidants, and betulinic acid. This study sought to investigate antiangiogenic and anti-colon cancer effects of S.C. standardized methanolic extract.
    Matched MeSH terms: Syzygium/chemistry*
  2. Fulltext Isolation, Characterization, Crystal Structure Elucidation, and Anticancer Study of Dimethyl Cardamonin, Isolated from Syzygium campanulatum Korth
    Memon AH, Ismail Z, Aisha AF, Al-Suede FS, Hamil MS, Hashim S, et al.
    Evid Based Complement Alternat Med, 2014;2014:470179.
    PMID: 25530783 DOI: 10.1155/2014/470179
    Syzygium campanulatum Korth is an equatorial, evergreen, aboriginal shrub of Malaysia. Conventionally it has been used as a stomachic. However, in the currently conducted study dimethyl cardamonin or 2',4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone (DMC) was isolated from S. campanulatum Korth, leaf extract. The structural characterization of DMC was carried out by making use of various techniques including UV, IR, NMR spectral followed by LC-MS, and X-ray crystallographic techniques. For determining the purity of compound, highly effective techniques including TLC, HPLC, and melting point were used. The cytotoxicity of DMC and three different extracts of S. campanulatum was evaluated against human colon cancer cell line (HT-29) by three different assays. DMC and ethanolic extract revealed potent and dose-dependent cytotoxic activity on the cancer cell line with IC50 12.6 and 90.1 µg/mL, respectively. Quite astonishingly to our knowledge, this is the very first report on S. campanulatum as being a rich source (3.5%) of DMC, X-ray crystallography, and anticancer activity on human colon cancer cells.
    Matched MeSH terms: Syzygium
  3. A facile, bio-based, novel approach for synthesis of covalently functionalized graphene nanoplatelet nano-coolants toward improved thermo-physical and heat transfer properties
    Sadri R, Hosseini M, Kazi SN, Bagheri S, Abdelrazek AH, Ahmadi G, et al.
    J Colloid Interface Sci, 2018 Jan 01;509:140-152.
    PMID: 28898734 DOI: 10.1016/j.jcis.2017.07.052
    In this study, we synthesized covalently functionalized graphene nanoplatelet (GNP) aqueous suspensions that are highly stable and environmentally friendly for use as coolants in heat transfer systems. We evaluated the heat transfer and hydrodynamic properties of these nano-coolants flowing through a horizontal stainless steel tube subjected to a uniform heat flux at its outer surface. The GNPs functionalized with clove buds using the one-pot technique. We characterized the clove-treated GNPs (CGNPs) using X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). We then dispersed the CGNPs in distilled water at three particle concentrations (0.025, 0.075 and 0.1wt%) in order to prepare the CGNP-water nanofluids (nano-coolants). We used ultraviolet-visible (UV-vis) spectroscopy to examine the stability and solubility of the CGNPs in the distilled water. There is significant enhancement in thermo-physical properties of CGNPs nanofluids relative those for distilled water. We validated our experimental set-up by comparing the friction factor and Nusselt number for distilled water obtained from experiments with those determined from empirical correlations, indeed, our experimental set-up is reliable and produces results with reasonable accuracy. We conducted heat transfer experiments for the CGNP-water nano-coolants flowing through the horizontal heated tube in fully developed turbulent condition. Our results are indeed promising since there is a significant enhancement in the Nusselt number and convective heat transfer coefficient for the CGNP-water nanofluids, with only a negligible increase in the friction factor and pumping power. More importantly, we found that there is a significant increase in the performance index, which is a positive indicator that our nanofluids have potential to substitute conventional coolants in heat transfer systems because of their overall thermal performance and energy savings benefits.
    Matched MeSH terms: Syzygium
  4. Fulltext Antihyperglycemic Effect of Methanol Extract of Syzygium polyanthum (Wight.) Leaf in Streptozotocin-Induced Diabetic Rats
    Widyawati T, Yusoff NA, Asmawi MZ, Ahmad M
    Nutrients, 2015 Sep;7(9):7764-80.
    PMID: 26389944 DOI: 10.3390/nu7095365
    Syzygium polyanthum (S. polyanthum), a plant belonging to Myrtaceae, is widely used in Indonesian and Malaysian cuisines. Diabetic patients in Indonesia also commonly use it as a traditional medicine. Hence, this study was conducted to investigate the antihyperglycemic effect of the methanol extract (ME) of S. polyanthum leaf and its possible mechanisms of action. To test for hypoglycemic activity, ME was administered orally to normal male Sprague Dawley rats after a 12-h fast. To further test for antihyperglycemic activity, the same treatment was administered to glucose-loaded (intraperitoneal glucose tolerance test, IPGTT) and streptozotocin (STZ)-induced diabetic rats, respectively. Hypoglycemic test in normal rats did not show significant reduction in blood glucose levels (BGLs) by the extract. Furthermore, IPGTT conducted on glucose-loaded normal rats also did not show significant reduction of BGLs. However, repeated administration of metformin and three doses of ME (250, 500 and 1000 mg/kg) for six days caused significant reduction of fasting BGLs in STZ-induced diabetic rats. The possible mechanisms of action of S. polyanthum antihyperglycemic activity were assessed by measurement of intestinal glucose absorption and glucose uptake by isolated rat abdominal muscle. It was found that the extract not only inhibited glucose absorption from the intestine but also significantly increased glucose uptake in muscle tissue. A preliminary phytochemical qualitative analysis of ME indicated the presence of tannins, glycosides, flavonoids, alkaloids and saponins. Additionally, Gas Chromatography-Mass Spectrometry (GC-MS) analysis detected squalene. In conclusion, S. polyanthum methanol leaf extract exerts its antihyperglycemic effect possibly by inhibiting glucose absorption from the intestine and promoting glucose uptake by the muscles.
    Matched MeSH terms: Syzygium
  5. Effects of the phloemic stress on the growth, development and quality of wax apple (Syzygium samarangense) cv. jambu madu
    Mohammad Moneruzzaman Khandaker, Normaniza Osman, Abm Sharif Hossain, Amru Nasrulhaq Boyce
    Sains Malaysiana, 2012;41:553-560.
    A study was carried out to investigate the effects of different girdling techniques on the growth, development and quality of red wax apple fruits (Syzygium samarangense). Selected horticultural parameters were monitored at one week interval during the growth period from December 2008 to October 2010, using I, C, V shaped, 50%, and 100% girdling. Girdling was applied 2 weeks before flowering. The results showed that the C-shaped girdling technique produced the best results with regard to the fruit setting and chlorophyll content in comparison to the control and the other girdling
    techniques employed. Furthermore, C-shaped girdling enhanced faster fruit growth producing the best final fruit length and diameter. In addition to significantly increased yield, juice percentage, leaf dry matter, biomass and TSS content of fruits. It was also observed that 50% girdling decreased fruit dropping. V-shaped girdling also increased the number of bud and reduced bud dropping compared to control. I-shaped girdle fruits produced the highest amount of K+ content in fruit juice compared to other treatments. The color development of the fruit peel in 100% girdling was also the highest among the treatments. From this study, it can be concluded that C-shaped girdling applied two weeks before flowering produced better fruit growth, yield and quality of red wax apple fruits under field conditions.
    Matched MeSH terms: Syzygium
  6. Lead contamination in Eugenia dyeriana herbal preparations from different commercial sources in Malaysia
    Ang HH
    Food Chem Toxicol, 2008 Jun;46(6):1969-75.
    PMID: 18328612 DOI: 10.1016/j.fct.2008.01.037
    The Drug Control Authority (DCA) of Malaysia implemented the phase three registration of traditional medicines on 1 January, 1992. A total of 100 products in various pharmaceutical dosage forms of a herbal preparation, containing Eugenia dyeriana, either single or combined preparations (more than one medicinal plant), were analyzed for the presence of lead contamination, using atomic absorption spectrophotometry. These samples were bought from different commercial sources in the Malaysian market, after performing a simple random sampling. Results showed that 22% of the above products failed to comply with the quality requirement for traditional medicines in Malaysia. Although this study showed that 78% of the products fully complied with the quality requirement for traditional medicines in Malaysia pertaining to lead, however, they cannot be assumed safe from lead contamination because of batch-to-batch inconsistency.
    Matched MeSH terms: Syzygium/chemistry*
  7. A bio-based, facile approach for the preparation of covalently functionalized carbon nanotubes aqueous suspensions and their potential as heat transfer fluids
    Sadri R, Hosseini M, Kazi SN, Bagheri S, Zubir N, Solangi KH, et al.
    J Colloid Interface Sci, 2017 Oct 15;504:115-123.
    PMID: 28531649 DOI: 10.1016/j.jcis.2017.03.051
    In this study, we propose an innovative, bio-based, environmentally friendly approach for the covalent functionalization of multi-walled carbon nanotubes using clove buds. This approach is innovative because we do not use toxic and hazardous acids which are typically used in common carbon nanomaterial functionalization procedures. The MWCNTs are functionalized in one pot using a free radical grafting reaction. The clove-functionalized MWCNTs (CMWCNTs) are then dispersed in distilled water (DI water), producing a highly stable CMWCNT aqueous suspension. The CMWCNTs are characterized using Raman spectroscopy, X-ray photoelectron spectroscopy and transmission electron microscopy. The electrostatic interactions between the CMWCNT colloidal particles in DI water are verified via zeta potential measurements. UV-vis spectroscopy is also used to examine the stability of the CMWCNTs in the base fluid. The thermo-physical properties of the CMWCNT nano-fluids are examined experimentally and indeed, this nano-fluid shows remarkably improved thermo-physical properties, indicating its superb potential for various thermal applications.
    Matched MeSH terms: Syzygium
  8. Fulltext Antioxidant activity and phenolic content of Paederia foetida and Syzygium aqueum
    Osman H, Rahim AA, Isa NM, Bakhir NM
    Molecules, 2009;14(3):970-8.
    PMID: 19305354 DOI: 10.3390/molecules14030970
    The antioxidant activity of fresh and dried plant extracts of Paederia foetida and Syzygium aqueum were studied using beta-carotene bleaching and the 2,2'-azinobis(3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) radical cation assay. The percentage of antioxidant activity for all extract samples using both assays was between 58 and 80%. The fresh samples of both plants had higher antioxidant activity than the dried samples. The results of the beta-carotene bleaching assay were correlated (R(2) = 0.9849) with those of the ABTS assay.
    Matched MeSH terms: Syzygium/chemistry*
  9. Fulltext Inhibition of quorum sensing-controlled virulence factor production in Pseudomonas aeruginosa PAO1 by Ayurveda spice clove (Syzygium aromaticum) bud extract
    Krishnan T, Yin WF, Chan KG
    Sensors (Basel), 2012;12(4):4016-30.
    PMID: 22666015 DOI: 10.3390/s120404016
    Quorum sensing controls the virulence determinants in most proteobacteria. In this work, the hexane, chloroform and methanol extracts of an Ayurveda spice, namely clove (Syzygium aromaticum), shown anti-quorum sensing activity. Hexane and methanol extracts of clove inhibited the response of C. violaceum CV026 to exogenously supplied N-hexanoylhomoserine lactone, in turn preventing violacein production. Chloroform and methanol extracts of clove significantly reduced bioluminescence production by E. coli [pSB1075] grown in the presence of N-(3-oxododecanoyl)-L-homoserine lactone. We demonstrated that clove extract inhibited quorum sensing-regulated phenotypes in Pseudomonas aeruginosa PA01, including expression of lecA::lux (by hexane extract), swarming (maximum inhibition by methanol extract), pyocyanin (maximum inhibition by hexane extract). This study shows that the presence of natural compounds that exhibit anti-quorum sensing activity in the clove extracts may be useful as the lead of anti-infective drugs.
    Matched MeSH terms: Syzygium/chemistry*
  10. Presence of calcium antagonist activity explains the use of Syzygium samarangense in diarrhoea
    Ghayur MN, Gilani AH, Khan A, Amor EC, Villaseñor IM, Choudhary MI
    Phytother Res, 2006 Jan;20(1):49-52.
    PMID: 16397921
    Syzygium samarangense (Family; Myrtaceae) or 'makopa', as it is commonly known, is native to Malaysia, some islands of Indonesia and to Far East in general. This study was undertaken to rationalize the use of this plant in hypermotility states of the gut. The hexane extract of S. samarangense (Ss.Hex) was found to dose-dependently (10-3000 microg/mL) relax the spontaneously contracting isolated rabbit jejunum. When tested for a possible calcium channel blocking (CCB) activity, the extract (10-1000 microg/mL) relaxed the high K+-induced contractions and also decreased the Ca++ dose-response curves in a dose-dependent manner (30-100 microg/mL), confirming the CCB activity. Four flavonoids isolated from the hexane extract were tested for a possible spasmolytic activity. All flavonoids, identified as: 2'-hydroxy-4',6'-dimethoxy-3'-methylchalcone (SS1), 2',4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone (SS2), 2',4'-dihydroxy-6'-methoxy-3'-methylchalcone (SS3) and 7-hydroxy-5-methoxy-6,8-dimethylflavanone (SS4), showed dose-dependent (10-1000 microg/mL) spasmolytic activity with SS2 being the most potent. These results indicate that the presence of compounds with spasmolytic and calcium antagonist activity may be responsible for the medicinal use of the plant in diarrhoea.
    Matched MeSH terms: Syzygium/chemistry*
  11. Fulltext Ecology, Epidemiology and Disease Management of Ralstonia syzygii in Indonesia
    Safni I, Subandiyah S, Fegan M
    Front Microbiol, 2018;9:419.
    PMID: 29662468 DOI: 10.3389/fmicb.2018.00419
    Ralstonia solanacearum species complex phylotype IV strains, which have been primarily isolated from Indonesia, Australia, Japan, Korea, and Malaysia, have undergone recent taxonomic and nomenclatural changes to be placed in the species Ralstonia syzygii. This species contains three subspecies; Ralstonia syzygii subsp. syzygii, a pathogen causing Sumatra disease of clove trees in Indonesia, Ralstonia syzygii subsp. indonesiensis, the causal pathogen of bacterial wilt disease on a wide range of host plants, and Ralstonia syzygii subsp. celebesensis, the causal pathogen of blood disease on Musa spp. In Indonesia, these three subspecies have devastated the cultivation of susceptible host plants which have high economic value. Limited knowledge on the ecology and epidemiology of the diseases has hindered the development of effective control strategies. In this review, we provide insights into the ecology, epidemiology and disease control of these three subspecies of Ralstonia syzygii.
    Matched MeSH terms: Syzygium
  12. The potential exploitation of the Malay-red apple (Syzygium malaccense) seed as source of a phosphorylated starch
    Santos GP, Miranda BM, Di-Medeiros MCB, Almeida VO, Ferreira RD, Morais DAB, et al.
    Carbohydr Res, 2024 Jan;535:109008.
    PMID: 38103463 DOI: 10.1016/j.carres.2023.109008
    This work presents the characterization of a novel naturally phosphorylated starch extracted from an unconventional and non-utilized source, the seeds of the stone fruit Syzygium malaccense. The morphology and chemical characteristics of the extracted starch were examined by scanning electron microscopy, FTIR, 1H/13C/31P NMR and 13C-CP/MAS-NMR, HPAEC-PAD chromatography, XRD, DSC, and RVA. The extraction yielded a highly pure starch (95.6 %) with an average granule size of 13 μm. The analysis of the starch components revealed an amylose content of 28.1 % and a predominance (65 %) of B-chains (B1-B3 65 %) in the amylopectin, as shown through HPAEC-PAD chromatography. The X-ray diffractogram was compatible with B-type starch, which was confirmed by the deconvolution of the C1 peak in the 13C-CP/MAS-NMR. X-Ray diffractogram also showed that S. malaccense has 28.5 % of crystallinity. DSC analysis showed values of 82.6 °C and -12.41 J g-1 for Tc and ΔH, respectively, which is compatible with a highly ordered starch granule structure. The values observed for peak (4678 mPa•s), trough (3055 mPa•s), and final viscosity (6526 mPa•s) indicated that S. malaccense may be used as a thickener in hot food.
    Matched MeSH terms: Syzygium*
  13. Two new phloroglucinol derivatives and five photosensitizing pheophorbides from Syzygium polyanthum leaves (Salam)
    Har LW, Shaari K, Boon LH, Kamarulzaman FA, Ismail IS
    Nat Prod Commun, 2012 Aug;7(8):1033-6.
    PMID: 22978223
    Two new phloroglucinol derivatives, identified as anthuminoate (1) and anthuminone (2), were isolated from the ichthyotoxic ethyl acetate fraction of Syzygium polyanthum leaves. In addition, bioassay-guided fractionation followed by dereplication of the photocytotoxic fraction of this plant part has resulted in the identification of five known pheophorbides as the bioactive constituents. The compounds were identified as pheophorbide-a, methyl pheophorbide-a, methyl hydroxypheophorbide-a, pheophorbide-b and hydroxypheophorbide-b. Inhibition of cell viability shown by the compounds ranged from 83.3 to 86.1% at a test concentration of 5 microg/mL. This shows that Syzygium polyanthum leaves are a potential new source in the studies of photocytotoxicity for photodynamic therapy.
    Matched MeSH terms: Syzygium/chemistry*
  14. Leucoxenols A and B, two new phenolics from Bornean medicinal plant Syzygium leucoxylon
    Shamsudin KJ, Phan CS, Kulip J, Hatai K, Vairappan CS, Kamada T
    J Asian Nat Prod Res, 2019 May;21(5):435-441.
    PMID: 29502443 DOI: 10.1080/10286020.2018.1440391
    The medicinal plant, Syzygium leucoxylon or commonly known as Obah found in North Borneo was considered as traditional medicine by local committee. Two new phenolics, leucoxenols A (1) and B (2) were isolated and identified as major secondary metabolites from the leaves of S. leucoxylon. Their chemical structures were elucidated based on spectroscopic data such as NMR and HRESIMS. Furthermore, these compounds were active against selected strains of fungi.
    Matched MeSH terms: Syzygium/chemistry*
  15. Anticoccidial and hepatoprotective effects of artemisinin liquid extract, cinnamon essential oil and clove essential oil against Eimeria stiedae infection in rabbits
    Sorour SS, Abou Asa S, Elhawary NM, Ghazy EW, Abd El Latif A, El-Abasy MA, et al.
    Trop Biomed, 2018 Dec 01;35(4):926-943.
    PMID: 33601842
    Coccidiosis is one of the most dangerous diseases that affect poultry, resulting in worldwide economic losses. Plant extracts and essential oils have been used as potential alternatives for chemotherapeutics, because they don't have the negative consequence of creating tissue residue and drug resistance. Therefore, this study had been conducted to determine the efficacy of artemisinin liquid extract, cinnamon essential oil and clove essential oil against Eimeria stiedae in rabbits. Sixty New Zealand white rabbits were divided into six equal groups, where group 1 and group 2 represented the negative and the positive controls, respectively, and groups 3-6 were infected with Eimeria stiedae and received 15 ppm toltrazuril, 200 ppm artemisinin, 100 mg/kg cinnamon oil, and 100 mg/kg clove oil, respectively. The results showed that artemisinin had a significant beneficial role in protection against hepatic coccidiosis: it mitigated the clinical symptoms, reduced the mortality rates, improved body weight and feed conversion, decreased the oocyst output, prevented oxidative stress, improved biochemical parameters, and decreased the lesion formation. Moreover, it has been found that cinnamon and clove essential oils induced partial protection against hepatic coccidiosis. Our findings suggested that artemisinin liquid extract and cinnamon and clove essential oils could be used for protection against hepatic coccidiosis. However, further investigations are needed in order to elucidate the active components, optimal doses, and mode of action of these extracts and essential oils before their clinical applications.
    Matched MeSH terms: Syzygium
  16. Comparative studies on the effect of crude aqueous (CA) and solvent (CM) extracts of clove on the cariogenic properties of Streptococcus mutans
    Rahim ZH, Khan HB
    J Oral Sci, 2006 Sep;48(3):117-23.
    PMID: 17023743
    A study was conducted to compare the efficiency of crude aqueous (CA) and solvent extracts (CM) of clove on the caries-inducing properties of Streptococcus mutans. The cariogenic properties investigated included the cell adhesion, cell-surface hydrophobicity and glucan synthesis activities of S. mutans. There was a significant difference between the effect of the CA and CM extracts on the adhesion of S. mutans (P < 0.05) within a concentration range of 5-15 mg/ml, the CM extract demonstrating a slightly higher inhibitory effect. However, the effect of the CM extract on the cell-surface hydrophobicity of S. mutans was weaker than that of the CA extract. The two extracts were found to reduce the synthesis of water-insoluble glucan (WIG) by almost 50% at a concentration as low as 0.5 mg/ml and the CM extract exhibited a significantly higher inhibitory effect than the CA extract (P < 0.05). The present findings indicate that both the CA and CM extracts exert inhibitory effects on the cariogenic properties of S. mutans and that the CA extract is as equally effective as the CM extract.
    Matched MeSH terms: Syzygium*
  17. Antidiabetic Potential of Syzygium sp.: An Overview
    Zulcafli AS, Lim C, Ling AP, Chye S, Koh R
    Yale J Biol Med, 2020 Jun;93(2):307-325.
    PMID: 32607091
    Diabetes, characterized by hyperglycemia, is one of the most significant metabolic diseases, reaching alarming pandemic proportions. It can be due to the defects in insulin action, or secretion, or both. The global prevalence of diabetes is estimated at 425 million people in 2017, and expected to rise to 629 million by 2045 due to an increasing trend of unhealthy lifestyles, physical inactivity, and obesity. Several treatment options are available to diabetics, however, some of the antidiabetic drugs result in adverse side effects such as hypoglycemia. Hence, there has been a proliferation of studies on natural products with antidiabetic effects, including plants from the Myrtaceae family, such as Psidium guajava, Eucalyptus globulus,Campomanesia xanthocarpa, and more significantly, Syzygium sp. Previous studies have shown that a number of Syzygium species had potent antidiabetic effects and were safe for consumption. This review aims to discuss the antidiabetic potential of Syzygium sp., based on in vitro and in vivo evidence.
    Matched MeSH terms: Syzygium*
  18. Anticancer Potential of Syzygium Species: a Review
    Chua LK, Lim CL, Ling APK, Chye SM, Koh RY
    Plant Foods Hum Nutr, 2019 Mar;74(1):18-27.
    PMID: 30535971 DOI: 10.1007/s11130-018-0704-z
    Cancer is a preventable and treatable disease, however, the incidence rates are on the rise. Classical treatment modalities for cancer include surgery, radiotherapy and chemotherapy. However, these are associated with detrimental side effects such as nausea and emesis. Therefore, researchers currently vest interest in complementary and alternative medicines for cancer treatment and prevention. Plants such as Syzygium sp. are a common basis of complementary medicines due to its abundance of bioactive phytochemicals. Numerous natural compounds derived from Syzygium sp., such as phenolics, oleanolic acids, and betulinic acids, and dimethyl cardamonins, were reported to have anticancer effects. Many possess the ability to inhibit cell proliferation and induce apoptosis. In this review, we discuss the vast potential Syzygium sp. harbours as a source of anticancer natural compounds due to its abundance, easy acceptability, affordability and safety for regular consumption.
    Matched MeSH terms: Syzygium/chemistry*
  19. Fulltext Amelioration of high-fat diet-induced obesity and its associated complications by a myricetin derivative-rich fraction from Syzygium malaccense in C57BL/6J mice
    Nallappan D, Chua KH, Ong KC, Chong CW, Teh CSJ, Palanisamy UD, et al.
    Food Funct, 2021 Jul 05;12(13):5876-5891.
    PMID: 34019055 DOI: 10.1039/d1fo00539a
    Obesity is a driving factor in the onset of metabolic disorders. This study aims to investigate the effects of the myricetin derivative-rich fraction (MD) from Syzygium malaccense leaf extract on high-fat diet (HFD)-induced obesity and its associated complications and its influence on uncoupling protein-1 (UCP-1) and gut microbiota in C57BL/6J mice. Mice were randomly assigned into four groups (n = 6) and given a normal diet (ND) or high-fat diet (HFD) for 10 weeks to induce obesity. The HFD groups (continued with HFD) were administered 50 mg kg-1 MD (treatment), 50 mg kg-1 metformin (positive control) and normal saline (HFD and ND controls) daily for four weeks via oral gavage. The ten-week HFD-feeding resulted in hyperglycemia and elevated urinary oxidative indices. The subsequent MD administration caused significant weight reduction without appetite suppression and amelioration of insulin resistance, steatosis and dyslipidemia. Besides, MD significantly reduced lipid hydroperoxides and protein carbonyls in tissue homogenates and urine and elevated Trolox equivalent antioxidant capacity (TEAC), ferric reducing antioxidant power (FRAP) and reduced glutathione (GSH) and thus, alleviated oxidative stress. The weight reduction was correlated with downregulation of inflammatory markers and the increased UCP-1 level, suggesting weight loss plausibly through thermogenesis. The Akkermansia genus (reflects improved metabolic status) in the HFD50 group was more abundant than that in the HFD group while the non-enzymatic antioxidant markers were strongly associated with UCP-1. In conclusion, MD ameliorates obesity and its related complications possibly via the upregulation of UCP-1 and increased abundance of Akkermansia genus and is promising as a therapeutic agent in the treatment of obesity and its associated metabolic disorders.
    Matched MeSH terms: Syzygium/chemistry*
  20. Protective effect of myricetin derivatives from Syzygium malaccense against hydrogen peroxide-induced stress in ARPE-19 cells
    Arumugam B, Palanisamy UD, Chua KH, Kuppusamy UR
    Mol Vis, 2019;25:47-59.
    PMID: 30820141
    Purpose: Oxidative stress is implicated in the etiology of diabetes and its debilitating complications, such as diabetic retinopathy (DR). Various flavonoids have been reported to be useful in reducing DR progression. Myricetin derivatives (F2) isolated from leaf extract of Syzygium malaccense have the potential to serve as functional food as reported previously. The present study was performed with the aim of determining the antioxidant potential and protective effect of myricetin derivatives (F2) isolated from leaf extract of S. malaccense against glucose oxidase (GO)-induced hydrogen peroxide (H2O2) production that causes oxidative stress in ARPE-19 (RPE) cells.

    Methods: Antioxidant properties were assessed through various radical (DPPH, ABTS, and nitric oxide) scavenging assays and determination of total phenolic content and ferric reducing antioxidant power level. ARPE-19 cells were preincubated with samples before the addition of GO (to generate H2O2). Cell viability, change in intracellular reactive oxygen species (ROS), H2O2 levels in cell culture supernatant, and gene expression were assessed.

    Results: F2 showed higher antioxidant levels than the extract when assessed for radical scavenging activities and ferric reducing antioxidant power. F2 protected the ARPE-19 cells against GO-H2O2-induced oxidative stress by reducing the production of H2O2 and intracellular reactive oxygen species. This was achieved by the activation of nuclear factor erythroid 2-related factor 2 (Nrf2/NFE2L2) and superoxide dismutase (SOD2), as well as downregulation of nitric oxide producer (NOS2) at the transcriptional level.

    Conclusions: The results showed that myricetin derivatives from S. malaccense have the capacity to exert considerable exogenous antioxidant activities and stimulate endogenous antioxidant activities. Therefore, these derivatives have excellent potential to be developed as therapeutic agents for managing DR.

    Matched MeSH terms: Syzygium/chemistry*
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