Displaying publications 1 - 20 of 29 in total

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  1. Ee GC, See I, Teh SS, Daud S
    J Asian Nat Prod Res, 2014;16(7):790-4.
    PMID: 24670077 DOI: 10.1080/10286020.2014.901313
    Our phytochemical study on the stem bark of Garcinia mangostana has led to the discovery of a new furanoxanthone, mangaxanthone A (1), together with five known analogs. The five known analogs that were isolated are α-mangostin (2), β-mangostin (3), cowagarcinone B (4), and dulcisxanthone F (5). The structural elucidations of these compounds were carried out by interpreting their spectroscopic data, mainly 1D and 2D NMR spectra and MS.
    Matched MeSH terms: Xanthones/isolation & purification*
  2. Ee GC, Foo CH, Jong VY, Ismail NH, Sukari MA, Taufiq Yap YH, et al.
    Nat Prod Res, 2012;26(9):830-5.
    PMID: 22044165 DOI: 10.1080/14786419.2011.559640
    A detailed chemical study on the stem bark of Garcinia nitida has led to the isolation of five xanthones. They are 1,6-dihydroxy-5-methoxy-6,6-dimethylpyrano[2',3':2,3]-xanthone (1), inophyllin B (2), osajaxanthone (3), 3-isomangostin (4) and rubraxanthone (5). The structures of these compounds were established using mainly 1-D and 2-D NMR spectroscopy ((1)H, (13)C, DEPT, COSY, HMBC and HMQC) while molecular masses were determined via MS techniques; 1 is a new compound.
    Matched MeSH terms: Xanthones/isolation & purification*
  3. Kar Wei L, Zamakshshari NH, Ee GCL, Mah SH, Mohd Nor SM
    Nat Prod Res, 2018 Sep;32(18):2147-2151.
    PMID: 28826239 DOI: 10.1080/14786419.2017.1367781
    Two naturally occurring xanthones, ananixanthone (1) and β-mangostin (2), were isolated using column chromatographic method from the n-hexane and methanol extracts of Calophyllum teysmannii, respectively. The major constituent, ananixanthone (1), was subjected to structural modifications via acetylation, methylation and benzylation yielding four new xanthone derivatives, ananixanthone monoacetate (3), ananixanthone diacetate (4), 5-methoxyananixanthone (5) and 5-O-benzylananixanthone (6). Compound 1 together with its four new derivatives were subjected to MTT assay against three cancer cell lines; SNU-1, K562 and LS174T. The results indicated that the parent compound has greater cytotoxicity capabilities against SNU-1 and K562 cell lines with IC50 values of 8.97 ± 0.11 and 2.96 ± 0.06 μg/mL, respectively. Compound 5 on the other hand exhibited better cytotoxicity against LS174T cell line with an IC50 value of 5.76 ± 1.07 μg/mL.
    Matched MeSH terms: Xanthones/isolation & purification
  4. Nasir NM, Rahmani M, Shaari K, Ee GC, Go R, Kassim NK, et al.
    Molecules, 2011 Oct 25;16(11):8973-80.
    PMID: 22027953 DOI: 10.3390/molecules16118973
    The air-dried powdered stem bark of Calophyllum nodusum (Guttiferea) collected from Sandakan (Sabah, Malaysia), was extracted sequentially with hexane, chloroform and methanol. The solvents were removed by rotary evaporator to give dark viscous extracts. Detailed and repeated chromatographic separation of the extracts lead to isolation of two new xanthones, identified as nodusuxanthone and trapezifolixanthone A. Other common terpenoids such as betulinic acid, lupeol, stigmasterol and friedelin were also isolated from the extracts and identified. The structures of the compounds were established by detailed spectral analysis and comparison with previously reported data.
    Matched MeSH terms: Xanthones/isolation & purification*
  5. Ee GC, Teo SH, Rahmani M, Lim CK, Lim YM, Go R
    Nat Prod Res, 2011 Jun;25(10):995-1003.
    PMID: 21644180 DOI: 10.1080/14786419.2010.534471
    A new furanodihydrobenzoxanthone, artomandin (1), together with three other flavonoid derivatives, artoindonesianin C, artonol B, and artochamin A, as well as β-sitosterol were isolated from the stem bark of Artocarpus kemando. The structures of these compounds were determined on the basis of spectral evidence. All of these compounds displayed inhibition effects to a very susceptible degree in cancer cell line tests. Compound 1 also exhibited significant antioxidant capacity in the free radical 1,1-diphenyl-2-picrylhydrazyl tests.
    Matched MeSH terms: Xanthones/isolation & purification*
  6. Taher M, Idris MS, Ahmad F, Arbain D
    Phytochemistry, 2005 Mar;66(6):723-6.
    PMID: 15771897
    A polyisoprenylated ketone named enervosanone has been isolated from the stem bark of Calophyllum enervosum together with three known compounds, cambogin, osajaxanthone and epicatechin. Their structures were determined by spectroscopic analysis. The antimicrobial evaluations of the isolated compounds were also reported.
    Matched MeSH terms: Xanthones/isolation & purification*
  7. Bin Ismail AA, Ee GC, Bin Daud S, Teh SS, Hashim NM, Awang K
    J Asian Nat Prod Res, 2015;17(11):1104-8.
    PMID: 26023810 DOI: 10.1080/10286020.2015.1047353
    A new pyranoxanthone, venuloxanthone (1), was isolated from the stem bark of Calophyllum venulosum, together with three other xanthones, tovopyrifolin C (2), ananixanthone (3) and caloxanthone I (4), along with two common triterpenes, friedelin (5) and lupeol (6). The structures of these compounds were identified using several spectroscopic analyses which are NMR, GCMS and FTIR experiments.
    Matched MeSH terms: Xanthones/isolation & purification*
  8. Ng HS, Tan GYT, Lee KH, Zimmermann W, Yim HS, Lan JC
    J Biosci Bioeng, 2018 Oct;126(4):507-513.
    PMID: 29764763 DOI: 10.1016/j.jbiosc.2018.04.008
    The α- and γ-mangostins from Garcinia mangostana pericarps (GMP) exhibit antioxidant, anti-bacterial, anti-inflammatory and anti-tumor properties. The extraction yields α- and γ-mangostins are often limited by the presence of the GMP cell walls. Therefore, the extraction and recovery of mangostins from GMP with an Aspergillus niger cellulase-assisted aqueous micellar biphasic system (CA-AMBS) was developed for enhanced yield of mangostins. Effects of the concentration of cellulase, the incubation time and the temperature of the system on the recovery of mangostins were investigated. The optimum condition for the recovery of α- and γ-mangostins was obtained with the addition of 0.5% (w/w) cellulase incubated at 40°C for 2 h. High log partition coefficients of α-mangostins (log Kα 4.79 ± 0.02) and γ-mangostins (log Kγ 4.02 ± 0.02) were achieved. High yields of α-mangostins (73.4%) and γ-mangostins (14.0%) were obtained from the micelle-rich bottom phase with final concentrations of 3.67 mg/mL and 0.70 mg/mL, respectively. The back-extraction of mangostins was performed with the addition of 30% (w/w) of isopropanol and 0.05 M of KCl at pH 9 to the bottom phase of the CA-AMBS. The yields of the α- and γ-mangostins from GMP were considerably enhanced with the CA-AMBS and the direct recovery of mangostins was demonstrated without additional downstream processing steps.
    Matched MeSH terms: Xanthones/isolation & purification
  9. Eukun Sage E, Jailani N, Md Taib AZ, Mohd Noor N, Mohd Said MI, Abu Bakar M, et al.
    PLoS One, 2018;13(10):e0205753.
    PMID: 30321238 DOI: 10.1371/journal.pone.0205753
    The pulp and pericarp of mangosteen (Garcinia mangostana) fruit are popular food, beverage and health products whereby 60% of the fruit consist of the pericarp. The major metabolite in the previously neglected or less economically significant part of the fruit, the pericarp, is the prenylated xanthone α-mangostin. This highly bioactive secondary metabolite is typically isolated using solvent extraction methods that involve large volumes of halogenated solvents either via direct or indirect extraction. In this study, we compared the quantities of α-mangostin extracted using three different extraction methods based on the environmentally friendly solvents methanol and ethyl acetate. The three solvent extractions methods used were direct extractions from methanol (DM) and ethyl acetate (DEA) as well as indirect extraction of ethyl acetate obtained via solvent partitioning from an initial methanol extract (IEA). Our results showed that direct extraction afforded similar and higher quantities of α-mangostin than indirect extraction (DM: 318 mg; DEA: 305 mg; IEA: 209 mg per 5 g total dried pericarp). Therefore, we suggest that the commonly used method of indirect solvent extraction using halogenated solvents for the isolation of α-mangostin is replaced by single solvent direct extraction using the environmentally friendly solvents methanol or ethyl acetate.
    Matched MeSH terms: Xanthones/isolation & purification*
  10. Sidahmed HM, Hashim NM, Amir J, Abdulla MA, Hadi AH, Abdelwahab SI, et al.
    Phytomedicine, 2013 Jul 15;20(10):834-43.
    PMID: 23570997 DOI: 10.1016/j.phymed.2013.03.002
    Pyranocycloartobiloxanthone A (PA), a xanthone derived from the Artocarpus obtusus Jarret, belongs to the Moraceae family which is native to the tropical forest of Malaysia. In this study, the efficacy of PA as a gastroprotective compound was examined against ethanol-induced ulcer model in rats. The rats were pretreated with PA and subsequently exposed to acute gastric lesions induced by absolute ethanol. The ulcer index, gastric juice acidity, mucus content, histological analysis, glutathione (GSH) levels, malondialdehyde level (MDA), nitric oxide (NO) and non-protein sulfhydryl group (NP-SH) contents were evaluated in vivo. The activities of PA as anti-Helicobacter pylori, cyclooxygenase-2 (COX-2) inhibitor and free radical scavenger were also investigated in vitro. The results showed that the oral administration of PA protects gastric mucosa from ethanol-induced gastric lesions. PA pretreatment significantly (p<0.05) restored the depleted GSH, NP-SH and NO levels in the gastric homogenate. Moreover, PA significantly (p<0.05) reduced the elevated MDA level due to ethanol administration. The gastroprotective effect of PA was associated with an over expression of HSP70 and suppression of Bax proteins in the ulcerated tissue. In addition, PA exhibited a potent FRAP value and significant COX-2 inhibition. It also showed a significant minimum inhibitory concentration (MIC) against H. pylori bacterium. The efficacy of PA was accomplished safely without the presence of any toxicological parameters. The results of the present study indicate that the gastroprotective effect of PA might contribute to the antioxidant and anti-inflammatory properties as well as the anti-apoptotic mechanism and antibacterial action against Helicobacter pylori.
    Matched MeSH terms: Xanthones/isolation & purification
  11. Hashim NM, Rahmani M, Ee GC, Sukari MA, Yahayu M, Amin MA, et al.
    Molecules, 2012;17(5):6071-82.
    PMID: 22614861 DOI: 10.3390/molecules17056071
    One of the most promising plants in biological screening test results of thirteen Artocarpus species was Artocarpus obtusus FM Jarrett and detailed phytochemical investigation of powdered dried bark of the plant has led to the isolation and identification of three xanthones; pyranocycloartobiloxanthone A (1), dihydroartoindonesianin C (2) and pyranocycloartobiloxanthone B (3). These compounds were screened for antioxidant, antimicrobial and tyrosinase inhibitory activities. Pyranocycloartobiloxanthone A (1) exhibited a strong free radical scavenger towards DPPH free radicals with IC50 value of 2 µg/mL with prominent discoloration observed in comparison with standard ascorbic acid, α-tocopherol and quercetin, The compound also exhibited antibacterial activity against methicillin resistant Staphylococcus aureus (ATCC3359) and Bacillus subtilis (clinically isolated) with inhibition zone of 20 and 12 mm, respectively. However the other two xanthones were found to be inactive. For the tyrosinase inhibitory activity, again compound (1) displayed strong activity comparable with the standard kojic acid.
    Matched MeSH terms: Xanthones/isolation & purification
  12. Ee GC, Mah SH, Rahmani M, Taufiq-Yap YH, Teh SS, Lim YM
    J Asian Nat Prod Res, 2011 Oct;13(10):956-60.
    PMID: 21972812 DOI: 10.1080/10286020.2011.600248
    The stem bark extracts of Calophyllum inophyllum furnished one new furanoxanthone, inophinnin (1), in addition to inophyllin A (2), macluraxanthone (3), pyranojacareubin (4), 4-hydroxyxanthone, friedelin, stigmasterol, and betulinic acid. The structures of these compounds were determined by spectroscopic analysis of 1D and 2D NMR spectral data ((1)H, (13)C, DEPT, COSY, HMQC, and HMBC) while EI-MS gave the molecular mass. The new xanthone, inophinnin (1), exhibited some anti-inflammatory activity in nitric oxide assay.
    Matched MeSH terms: Xanthones/isolation & purification*
  13. Hashim N, Rahmani M, Sukari MA, Ali AM, Alitheen NB, Go R, et al.
    J Asian Nat Prod Res, 2010 Feb;12(2):106-12.
    PMID: 20390751 DOI: 10.1080/10286020903450411
    Two new xanthones, pyranocycloartobiloxanthone A (1) and dihydroartoindonesianin C (2), were isolated from the stem bark of Artocarpus obtusus Jarrett by chromatographic separation. Their structures were determined by using spectroscopic methods and comparison with known related compounds. Pyranocycloartobiloxanthone A (1) showed strong free radical scavenging activity by using DPPH assay as well as cytotoxicity towards K562, HL-60, and MCF7 cell lines.
    Matched MeSH terms: Xanthones/isolation & purification*
  14. Ee GC, Daud S, Izzaddin SA, Rahmani M
    J Asian Nat Prod Res, 2008 May-Jun;10(5-6):475-9.
    PMID: 18464091 DOI: 10.1080/10286020801948490
    Our current interest in searching for natural anti-cancer lead compounds from plants has led us to the discovery that the stem and roots of Garcinia mangostana can be a source of such compounds. The stem furnished 2,8-dihydroxy-6-methoxy-5-(3-methylbut-2-enyl)-xanthone (1), which is a new xanthone. Meanwhile, the root bark of the plant furnished six xanthones, namely alpha-mangostin (2), beta-mangostin (3), gamma-mangostin (4), garcinone D (5), mangostanol (6), and gartanin (7). The hexane and chloroform extracts of the root bark of G. mangostana as well as the hexane extract of the stem bark were found to be active against the CEM-SS cell line. gamma-Mangostin (4) showed good activity with a very low IC(50) value of 4.7 microg/ml, while alpha-mangostin (2), mangostanol (6), and garcinone D (5) showed significant activities with IC(50) values of 5.5, 9.6, and 3.2 microg/ml, respectively. This is the first report on the cytotoxicity of the extracts of the stem and root bark of G. mangostana and of alpha-mangostin, mangostanol, and garcinone D against the CEM-SS cell line.
    Matched MeSH terms: Xanthones/isolation & purification*
  15. Ee GC, Daud S, Taufiq-Yap YH, Ismail NH, Rahmani M
    Nat Prod Res, 2006 Oct;20(12):1067-73.
    PMID: 17127660
    Studies on the stem of Garcinia mangostana have led to the isolation of one new xanthone mangosharin (1) (2,6-dihydroxy-8-methoxy-5-(3-methylbut-2-enyl)-xanthone) and six other prenylated xanthones, alpha-mangostin (2), beta-mangostin (3), garcinone D (4), 1,6-dihydroxy-3,7-dimethoxy-2-(3-methylbut-2-enyl)-xanthone (5), mangostanol (6) and 5,9-dihydroxy-8- methoxy-2,2-dimethyl-7-(3-methylbut-2-enyl)-2H,6H-pyrano-[3,2-b]-xanthene-6-one (7). The structures of these compounds were determined by spectroscopic methods such as 1H NMR, 13C NMR, mass spectrometry (MS) and by comparison with previous studies. All the crude extracts when screened for their larvicidal activities indicated very good toxicity against the larvae of Aedes aegypti. This article reports the isolation and identification of the above compounds as well as bioassay data for the crude extracts. These bioassay data have not been reported before.
    Matched MeSH terms: Xanthones/isolation & purification
  16. Tan WN, Khairuddean M, Wong KC, Tong WY, Ibrahim D
    J Asian Nat Prod Res, 2016 Aug;18(8):804-11.
    PMID: 26999039 DOI: 10.1080/10286020.2016.1160071
    A new xanthone, namely garcinexanthone G (1), along with eight known compounds, stigmasta-5,22-dien-3β-ol (2), stigmasta-5,22-dien-3-O-β-glucopyranoside (3), 3β-acetoxy-11α,12α-epoxyoleanan-28,13β-olide (4), 2,6-dimethoxy-p-benzoquinone (5), 1,3,5-trihydroxy-2-methoxyxanthone (6), 1,3,7-trihydroxyxanthone (7), kaempferol (8) and quercetin (9), were isolated from the stem bark of Garcinia atroviridis. Their structures were elucidated based on spectroscopic methods including nuclear magnetic resonance (NMR-1D and 2D), UV, IR, and mass spectrometry. All the isolated compounds were evaluated for their antioxidant properties based on the DPPH radical scavenging activities. Results showed that 1,3,7-trihydroxyxanthone and quercetin showed significant antioxidant activities with EC50 values of 16.20 and 12.68 μg/ml, respectively, as compared to the control, ascorbic acid (7.4 μg/ml).
    Matched MeSH terms: Xanthones/isolation & purification*
  17. Ghasemzadeh A, Jaafar HZE, Baghdadi A, Tayebi-Meigooni A
    Molecules, 2018 Jul 25;23(8).
    PMID: 30044450 DOI: 10.3390/molecules23081852
    Since α-mangostin in mangosteen fruits was reported to be the main compound able to provide natural antioxidants, the microwave-assisted extraction process to obtain high-quality α-mangostin from mangosteen pericarp (Garcinia mangostana L.) was optimized using a central composite design and response surface methodology. The parameters examined included extraction time, microwave power, and solvent percentage. The antioxidant and antimicrobial activity of optimized and non-optimized extracts was evaluated. Ethyl acetate as a green solvent exhibited the highest concentration of α-mangostin, followed by dichloromethane, ethanol, and water. The highest α-mangostin concentration in mangosteen pericarp of 121.01 mg/g dry matter (DM) was predicted at 3.16 min, 189.20 W, and 72.40% (v/v). The verification of experimental results under these optimized conditions showed that the α-mangostin value for the mangosteen pericarp was 120.68 mg/g DM. The predicted models were successfully developed to extract α-mangostin from the mangosteen pericarp. No significant differences were observed between the predicted and the experimental α-mangostin values, indicating that the developed models are accurate. The analysis of the extracts for secondary metabolites showed that the total phenolic content (TPC) and total flavonoid content (TFC) increased significantly in the optimized extracts (OE) compared to the non-optimized extracts (NOE). Additionally, trans-ferulic acid and catechin were abundant among the compounds identified. In addition, the optimized extract of mangosteen pericarp with its higher α-mangostin and secondary metabolite concentrations exhibited higher antioxidant activities with half maximal inhibitory concentration (IC50) values of 20.64 µg/mL compared to those of the NOE (28.50 µg/mL). The OE exhibited the highest antibacterial activity, particularly against Gram-positive bacteria. In this study, the microwave-assisted extraction process of α-mangostin from mangosteen pericarp was successfully optimized, indicating the accuracy of the models developed, which will be usable in a larger-scale extraction process.
    Matched MeSH terms: Xanthones/isolation & purification
  18. Ibrahim MY, Mohd Hashim N, Mohan S, Abdulla MA, Abdelwahab SI, Kamalidehghan B, et al.
    Drug Des Devel Ther, 2014;8:2193-211.
    PMID: 25395836 DOI: 10.2147/DDDT.S66574
    BACKGROUND: Cratoxylum arborescens has been used traditionally in Malaysia for the treatment of various ailments.

    METHODS: α-Mangostin (AM) was isolated from C. arborescens and its cell death mechanism was investigated. AM-induced cytotoxicity was observed with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Acridine orange/propidium iodide staining and annexin V were used to detect cells in early phases of apoptosis. High-content screening was used to observe the nuclear condensation, cell permeability, mitochondrial membrane potential, and cytochrome c release. The role of caspases-3/7, -8, and -9, reactive oxygen species, Bcl-2 and Bax expression, and cell cycle arrest were also investigated. To determine the role of the central apoptosis-related proteins, a protein array followed by immunoblot analysis was conducted. Moreover, the involvement of nuclear factor-kappa B (NF-κB) was also analyzed.

    RESULTS: Apoptosis was confirmed by the apoptotic cells stained with annexin V and increase in chromatin condensation in nucleus. Treatment of cells with AM promoted cell death-transducing signals that reduced MMP by downregulation of Bcl-2 and upregulation of Bax, triggering cytochrome c release from the mitochondria to the cytosol. The released cytochrome c triggered the activation of caspase-9 followed by the executioner caspase-3/7 and then cleaved the PARP protein. Increase of caspase-8 showed the involvement of extrinsic pathway. AM treatment significantly arrested the cells at the S phase (P<0.05) concomitant with an increase in reactive oxygen species. The protein array and Western blotting demonstrated the expression of HSP70. Moreover, AM significantly blocked the induced translocation of NF-κB from cytoplasm to nucleus.

    CONCLUSION: Together, the results demonstrate that the AM isolated from C. arborescens inhibited the proliferation of MDA-MB-231 cells, leading to cell cycle arrest and programmed cell death, which was suggested to occur through both the extrinsic and intrinsic apoptosis pathways with involvement of the NF-κB and HSP70 signaling pathways.

    Matched MeSH terms: Xanthones/isolation & purification
  19. Mah SH, Ee GC, Teh SS, Sukari MA
    Nat Prod Res, 2015;29(1):98-101.
    PMID: 25229947 DOI: 10.1080/14786419.2014.959949
    Extensive chromatographic isolation and purification of the extracts of the stem bark of Calophyllum inophyllum and Calophyllum soulattri have resulted in 11 xanthones. C. inophyllum gave inophinnin (1), inophinone (2), pyranojacareubin (5), rheediaxanthone A (6), macluraxanthone (7) and 4-hydroxyxanthone (8), while C. soulattri afforded soulattrin (3), phylattrin (4), caloxanthone C (9), brasixanthone B (10) and trapezifolixanthone (11). The structures of these compounds were determined on the basis of spectroscopic analyses such as 1D and 2D NMR, GC-MS, IR and UV. Cytotoxicity screening (MTT assay) carried out in vitro on all the xanthones using five human cancer cell lines indicated good activities for some of these xanthones. The structure-activity relationship study revealed that the inhibitory activities exhibited by these xanthone derivatives to be closely related to the existence and nature of the pyrano and the prenyl substituent groups on their skeleton.
    Matched MeSH terms: Xanthones/isolation & purification*
  20. Daud SB, Ee GC, Malek EA, Teh SS, See I
    Nat Prod Res, 2014;28(19):1534-8.
    PMID: 24897077 DOI: 10.1080/14786419.2014.924001
    A new coumarin, hoseimarin (1), together with four other xanthones, trapezifolizanthone (2), osajaxanthone (3), β-mangostin (4) and caloxanthone A (5), were isolated from the stem bark of Calophyllum hosei. The structures of these compounds were established by using spectroscopic analysis which included (1)H NMR, (13)C NMR, COSY, DEPT, HMQC and HMBC experiments.
    Matched MeSH terms: Xanthones/isolation & purification
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