Displaying publications 1 - 20 of 25 in total

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  1. Lim KH, Kam TS
    Phytochemistry, 2008 Jan;69(2):558-61.
    PMID: 17631924
    Six alkaloids belonging to the methyl chanofruticosinate group, viz., prunifolines A-F, in addition to six other known methyl chanofruticosinate alkaloids, were isolated from the leaf extract of Kopsia arborea. The structures were determined using NMR and MS analysis and comparison with known related compounds.
    Matched MeSH terms: Apocynaceae/chemistry*
  2. Kalshetti MG, Argade NP
    Alkaloids Chem Biol, 2020;83:187-223.
    PMID: 32098650 DOI: 10.1016/bs.alkal.2019.12.001
    The tryptamine-derived polycyclic bridged bioactive indole alkaloids subincanadines A-G were isolated in 2002 by Ohsaki and coworkers from the bark of the Brazilian medicinal plant Aspidosperma subincanum. Kobayashi proposed that subincanadines D-F could be biosynthetically resulting from stemmadenine via two different pathways and, furthermore, that the subincanadines A-C could be biogenetically resulting from subincanadines D and E. Kam and coworkers, in their focused efforts, isolated five indole alkaloids from Malaysian Kopsia arborea species, namely valparicine, apparicine, arboridinine, arborisidine, and arbornamine in combination with subincanadine E. On the basis of structural features, it has been proposed and proved in some examples that subincanadine E is a biogenetic precursor of these five different bioactive indole alkaloids bearing complex structural architectures. All important information on isolation, characterization, bioactivity, probable biogenetic pathways, and more specifically racemic and enantioselective total synthesis of subincanadine alkaloids and their biogenetic congeners are summarized in the present chapter. Special importance is given to the total synthesis and the synthetic strategies intended therein, comprising a set of main reactions.
    Matched MeSH terms: Apocynaceae/chemistry*
  3. Wong SK, Lim YY, Abdullah NR, Nordin FJ
    PMID: 21232161 DOI: 10.1186/1472-6882-11-3
    Studies have shown that the barks and roots of some Apocynaceae species have anticancer and antimalarial properties. In this study, leaf extracts of five selected species of Apocynaceae used in traditional medicine (Alstonia angustiloba, Calotropis gigantea, Dyera costulata, Kopsia fruticosa and Vallaris glabra) were assessed for antiproliferative (APF) and antiplasmodial (APM) activities, and analysed for total alkaloid content (TAC), total phenolic content (TPC) and radical-scavenging activity (RSA). As V. glabra leaf extracts showed wide spectrum APF and APM activities, they were further screened for saponins, tannins, cardenolides and terpenoids.
    Matched MeSH terms: Apocynaceae/chemistry*
  4. Wong SK, Wong SP, Sim KS, Lim SH, Low YY, Kam TS
    J Nat Prod, 2019 07 26;82(7):1902-1907.
    PMID: 31241923 DOI: 10.1021/acs.jnatprod.9b00255
    Three new alkaloids were isolated from the bark extract of the Malayan Kopsia arborea, viz., arbophyllidine (1), an unusual pentacyclic, monoterpenoid indole characterized by an absence of oxygen atoms and incorporating a new carbon-nitrogen skeleton, and arbophyllinines A (2) and B (3), two pentacyclic corynanthean alkaloids incorporating a hydroxyethyl-substituted tetrahydrofuranone ring. The structures of the alkaloids were deduced based on analysis of the MS and NMR data and confirmed by X-ray diffraction analyses. The absolute configuration of arbophyllidine (1) was established based on experimental and calculated ECD data, while that of arbophyllinine A was based on X-ray diffraction analysis (Cu Kα). A reasonable biosynthetic route to arbophyllidine (1) from a pericine precursor is presented. Arbophyllidine (1) showed pronounced in vitro growth inhibitory activity against the HT-29 human cancer cell line with IC50 6.2 μM.
    Matched MeSH terms: Apocynaceae/chemistry*
  5. Chong KW, Yeap JS, Lim SH, Weber JF, Low YY, Kam TS
    J Nat Prod, 2017 11 22;80(11):3014-3024.
    PMID: 29087707 DOI: 10.1021/acs.jnatprod.7b00621
    Reexamination of the absolute configuration of recently isolated eburnane alkaloids from Malaysian Kopsia and Leuconotis species by X-ray diffraction analysis and ECD/TDDFT has revealed the existence of biosynthetic enantiodivergence. Three different scenarios are discerned with respect to the composition of the enantiomeric eburnane alkaloids in these plants: first, where the new eburnane congeners possess the same C-20, C-21 absolute configurations as the common eburnane alkaloids (eburnamonine, eburnamine, isoeburnamine, eburnamenine) occurring in the same plant; second, where the new eburnane congeners possess opposite or enantiomeric C-20, C-21 absolute configurations compared to the common eburnane alkaloids found in the same plant; and, third, where the four common eburnane alkaloids were isolated as racemic or scalemic mixtures, while the new eburnane congeners were isolated as pure enantiomers with a common C-20, C-21 configuration (20α, 21α). Additionally, the same Kopsia species (K. pauciflora) found in two different geographical locations (Peninsular Malaysia and Malaysian Borneo) showed different patterns in the composition of the enantiomeric eburnane alkaloids. Revision of the absolute configurations of a number of new eburnane congeners (previously assigned based on the assumption of a common biogenetic origin to that of the known eburnane alkaloids co-occurring in the same plant) is required based on the present results.
    Matched MeSH terms: Apocynaceae/chemistry*
  6. Mohanty SK, Swamy MK, Sinniah UR, Anuradha M
    Molecules, 2017 06 19;22(6).
    PMID: 28629185 DOI: 10.3390/molecules22061019
    Leptadenia reticulata (Retz.) Wight & Arn. (Apocynaceae), is a traditional medicinal plant species widely used to treat various ailments such as tuberculosis, hematopoiesis, emaciation, cough, dyspnea, fever, burning sensation, night blindness, cancer, and dysentery. In Ayurveda, it is known for its revitalizing, rejuvenating, and lactogenic properties. This plant is one of the major ingredients in many commercial herbal formulations, including Speman, Envirocare, Calshakti, Antisept, and Chyawanprash. The therapeutic potential of this herb is because of the presence of diverse bioactive compounds such as α-amyrin, β-amyrin, ferulic acid, luteolin, diosmetin, rutin, β-sitosterol, stigmasterol, hentricontanol, a triterpene alcohol simiarenol, apigenin, reticulin, deniculatin, and leptaculatin. However, most biological studies on L. reticulata are restricted to crude extracts, and many biologically active compounds are yet to be identified in order to base the traditional uses of L. reticulata on evidence-based data. At present, L. reticulata is a threatened endangered plant because of overexploitation, unscientific harvesting, and habitat loss. The increased demand from pharmaceutical, nutraceutical, and veterinary industries has prompted its large-scale propagation. However, its commercial cultivation is hampered because of the non-availability of genuine planting material and the lack of knowledge about its agronomical practices. In this regard, micropropagation techniques will be useful to obtain true-to-type L. reticulata planting materials from an elite germplasm to meet the current demand. Adopting other biotechnological approaches such as synthetic seed technology, cryopreservation, cell culture, and genetic transformation can help conservation as well as increased metabolite production from L. reticulata. The present review summarizes scientific information on the botanical, agronomical, phytochemical, pharmacological, and biotechnological aspects of L. reticulata. This comprehensive information will certainly allow better utilization of this industrially important herb towards the discovery of lead drug molecules.
    Matched MeSH terms: Apocynaceae/chemistry*
  7. Yap WS, Gan CY, Low YY, Choo YM, Etoh T, Hayashi M, et al.
    J Nat Prod, 2011 May 27;74(5):1309-12.
    PMID: 21428274 DOI: 10.1021/np200008g
    Three new indole alkaloids (1-3), named grandilodines A-C, and five known ones were obtained from the Malayan Kopsia grandifolia. The structures were established using NMR and MS analyses and, in the case of 1 and 2, were confirmed by X-ray diffraction analyses. Alkaloids 1, 3, and lapidilectine B (8) were found to reverse multidrug resistance in vincristine-resistant KB cells.
    Matched MeSH terms: Apocynaceae/chemistry*
  8. Gan CY, Low YY, Robinson WT, Komiyama K, Kam TS
    Phytochemistry, 2010 Aug;71(11-12):1365-70.
    PMID: 20542302 DOI: 10.1016/j.phytochem.2010.05.015
    Leucofoline and leuconoline, representing the first members of the aspidospermatan-aspidospermatan and eburnane-sarpagine subclasses of the bisindole alkaloids, respectively, were isolated from the Malayan Leuconotis griffithii. The structures of these bisindole alkaloids were established using NMR and MS analysis, and in the case of leuconoline, confirmed by X-ray diffraction analysis. Both alkaloids showed weak cytotoxicity towards human KB cells.
    Matched MeSH terms: Apocynaceae/chemistry*
  9. Gan CY, Etoh T, Hayashi M, Komiyama K, Kam TS
    J Nat Prod, 2010 Jun 25;73(6):1107-11.
    PMID: 20515042 DOI: 10.1021/np1001187
    Four new bisindole alkaloids of the Strychnos-Strychnos type, leucoridines A-D (1-4), were isolated from the stem-bark extract of Leuconotis griffithii. Alkaloids 1-4 showed moderate cytotoxicity against drug-sensitive and vincristine-resistant human KB cells.
    Matched MeSH terms: Apocynaceae/chemistry*
  10. Nugroho AE, Hirasawa Y, Kawahara N, Goda Y, Awang K, Hadi AH, et al.
    J Nat Prod, 2009 Aug;72(8):1502-6.
    PMID: 19388660 DOI: 10.1021/np900115q
    A new bisindole alkaloid, bisnicalaterine A (1), consisting of two vobasine-type skeletons, and 3-epivobasinol (2) and 3-O-methylepivobasinol (3), with vobasine-type skeletons, were isolated from the leaves of Hunteria zeylanica, and their structures were elucidated on the basis of spectroscopic data and chemical correlation. Bisnicalaterine A showed moderate cytotoxicity against various human cancer cell lines.
    Matched MeSH terms: Apocynaceae/chemistry*
  11. Lim SH, Sim KM, Abdullah Z, Hiraku O, Hayashi M, Komiyama K, et al.
    J Nat Prod, 2007 Aug;70(8):1380-3.
    PMID: 17608533
    Four new indole alkaloids were obtained from two Kopsia species, 6-oxoleuconoxine (1) from the leaf extract of K. griffithii and kopsinitarine E (2), kopsijasminine (3), and kopsonoline (4) from the stem-bark extract of K. teoi. The structures of these alkaloids were determined using NMR and MS analysis. Kopsijasminine (3) showed moderate activity in reversing multidrug resistance in vincristine-resistant KB cells.
    Matched MeSH terms: Apocynaceae/chemistry*
  12. Lim KH, Hiraku O, Komiyama K, Koyano T, Hayashi M, Kam TS
    J Nat Prod, 2007 Aug;70(8):1302-7.
    PMID: 17665953
    Nine new indole alkaloids, rhazinoline (1), 19(S)-methoxytubotaiwine (2), 19(R)-methoxytubotaiwine (3), kopsamidine A (4), kopsamidine B (5), kopsinidine A (6), kopsinidine B (7), paucidactine C (8), and pericine N-oxide (9), in addition to several recently reported novel indoles and 34 other known ones, were obtained from the stem-bark extract of the Malayan Kopsia arborea. The structures were determined using NMR and MS analysis. Valparicine (12) showed pronounced cytotoxic effects against KB and Jurkat cells (IC(50) 13.0 and 0.91 microM, respectively).
    Matched MeSH terms: Apocynaceae/chemistry*
  13. Sukmawati D, Shabrina A, Indrayanti R, Kurniati TH, Nurjayadi M, Hidayat I, et al.
    Recent Pat Food Nutr Agric, 2020;11(3):219-228.
    PMID: 32324527 DOI: 10.2174/2212798411666200423101159
    BACKGROUND: Apples often experience postharvest damage due to being attacked by mold organisms. Several groups of molds such as Aspergillus sp., Penicilium expansum, Botrytis cinerea, and Venturia sp. can cause a serious postharvest disease exhibited as watery regions where areas of blue-green tufts of spores develop. Current methods using fungicides to control pathogenic fungi can cause resistance if applied in the long term. An alternative procedure using yeast as a biological agent has been found.

    OBJECTIVE: The aim of this study is to screen potential yeast, which has the ability to inhibit the growth of Aspergillus brasielensis (isolate A1) and Aspergillus flavus section flavi (isolate A17) isolated from apple fruits.

    METHODS: Antagonism test using YMA dual culture medium using in vitro assays and ITS rDNA identification were performed.

    RESULTS: The result showed that 3 out of 19 yeast isolated from Cerbera manghas L, T1, T3 and T4, demonstrated the potential ability as a biocontrol agent. ITS rDNA identification demonstrated that T1 has a similarity to Rhodotorula mucilaginosa while T3 and T4 were identified as Aureobasidium sp. nov. The 3 isolates exhibited the ability to reduce the growth of A. brasiliensis sensu lato better than dithane 0.3% with a Disease Incidence (DI) of 100% and a Disease Severity (DS) value of 45%. Only isolate T1 and T3 were able to reduce decay symptoms in apples inoculated with A. flavus sensu lato (with DO and DS were 100% and 25%, respectively) compared to dithane pesticides 0.3%.

    CONCLUSION: This study indicated that competition between nutrients occurs between pathogenic molds and under-yeast in vitro and in vivo conditions. However, further studies in the future might be able to elucidate the 'killer' activity and interaction with the pathogen cells and the bio-product production using Rhodotorula mucilaginosa and Aureoubasidium namibiae strains to control postharvest diseases.

    Matched MeSH terms: Apocynaceae/chemistry*
  14. Al Nasr IS
    Trop Biomed, 2020 Mar 01;37(1):15-23.
    PMID: 33612714
    The organisms of the genus Leishmania are flagellated protozoan parasites and are the causative agents of leishmaniasis. This disease is a major health problem, especially in tropical countries. Currently, cutaneous leishmaniasis is treated by chemotherapy using pentavalent antimonials, but these drugs have serious organo-toxicity, drug resistance on several occasions, and low efficiency in controlling the infection. The present work is carried out to evaluate the in vitro antileishmanial activity of methanolic extracts and phytochemical fractions of two plants ethnobotanically used against leishmaniasis and skin infection, Calotropis procera and Rhazya stricta leaves against Leishmania major promastigote and amastigote stages and cytotoxicity against the Vero cell line. The leaves of C. procera and R. stricta were extracted with methanol and fractionated by petroleum ether, chloroform, ethyl acetate, n-butanol, and water. The methanolic extracts of the leaves of C. procera and R. stricta exhibited antileishmanial activity against L. major promastigotes with IC50 values of 66.8 and 42.4 µg mL-1, respectively. While their CC50 2.3 and 298 µg mL-1 and their SI 0.03 and 7.03 respectively. However, the fractionations of the methanolic extract of C. procera leaves revealed antiparasitic activity against both L. major promastigote and amastigote stages in vitro, which significantly increased with polarity with the exception of n-butanol. Hence the best activity was revealed by the water fraction (IC50 of 26.3 and 29.0 µg mL-1) for the two stages. In conclusion, further phytochemical investigation should be performed for the C. procera water extract in terms of antileishmanial active ingredient isolation that may enhance the possibility of avoiding toxic substances and overcome the low SI (1.1 and 1.01).
    Matched MeSH terms: Apocynaceae/chemistry*
  15. Yap WS, Gan CY, Sim KS, Lim SH, Low YY, Kam TS
    J Nat Prod, 2016 Jan 22;79(1):230-9.
    PMID: 26717050 DOI: 10.1021/acs.jnatprod.5b00992
    Eleven new indole alkaloids (1-11) comprising seven aspidofractinine and four eburnane alkaloids, were isolated from the stem-bark extract of Kopsia pauciflora occurring in Malaysian Borneo. The aspidofractinine alkaloids include a ring-contracted, an additional ring-fused, a paucidactine regioisomer, two paucidactine, and one kopsine alkaloid. The structures of several of these alkaloids were also confirmed by X-ray diffraction analyses. The bisindole alkaloids isolated, norpleiomutine and kopsoffinol, showed in vitro growth inhibitory activity against human PC-3, HCT-116, MCF-7, and A549 cells and moderate effects in reversing multidrug-resistance in vincristine-resistant human KB cells.
    Matched MeSH terms: Apocynaceae/chemistry*
  16. Gan CY, Yoganathan K, Sim KS, Low YY, Lim SH, Kam TS
    Phytochemistry, 2014 Dec;108:234-42.
    PMID: 25442910 DOI: 10.1016/j.phytochem.2014.09.014
    Eleven indole alkaloids, comprising four corynanthean, two eburnane, one aspidofractinine, one secoleuconoxine, one andranginine, and two pauciflorine type alkaloids were isolated from the stem-bark and leaf extracts of Kopsia pauciflora. Their structures were determined using NMR and MS analyses. The catharinensine type alkaloid kopsirensine B and the secoleuconoxine alkaloid arboloscine A showed moderate to weak activity in reversing MDR in vincristine-resistant KB cells. The alkaloid content was markedly different compared to that of a sample from Malaysian Borneo.
    Matched MeSH terms: Apocynaceae/chemistry*
  17. Gan CY, Robinson WT, Etoh T, Hayashi M, Komiyama K, Kam TS
    Org. Lett., 2009 Sep 3;11(17):3962-5.
    PMID: 19708704 DOI: 10.1021/ol9016172
    A cytotoxic bisindole alkaloid possessing an unprecedented structure constituted from the union of an eburnan half and a novel vinylquinoline alkaloid has been isolated from Leuconotis griffithii. The structure was established by analysis of the spectroscopic data and confirmed by X-ray diffraction analysis. A possible biogenetic pathway to the novel quinolinic coupling partner is presented from an Aspidosperma precursor.
    Matched MeSH terms: Apocynaceae/chemistry*
  18. Subramaniam G, Hiraku O, Hayashi M, Koyano T, Komiyama K, Kam TS
    J Nat Prod, 2008 Jan;71(1):53-7.
    PMID: 18078327
    Ten new indole alkaloids of the aspidofractinine type, in addition to several recently reported indole alkaloids and 20 other known alkaloids, were obtained from the leaf and stem-bark extract of the Malayan Kopsia singapurensis, viz., kopsimalines A-E (1-5), kopsinicine (6), kopsofinone (7), and kopsiloscines H-J (8-10). The structures of these alkaloids were determined using NMR and MS analysis. Kopsimalines A (1), B (2), C (3), D (4), and E (5) and kopsiloscine J (10) were found to reverse multidrug-resistance in vincristine-resistant KB cells, with 1 showing the highest potency.
    Matched MeSH terms: Apocynaceae/chemistry*
  19. Ahmad K, Thomas NF, Hadi AH, Mukhtar MR, Mohamad K, Nafiah MA, et al.
    Chem Pharm Bull (Tokyo), 2010 Aug;58(8):1085-7.
    PMID: 20686264
    A phytochemical study on the bark of Neisosperma oppositifolia (Apocynaceae) yielded two new beta-carboline indole alkaloids, oppositinines A (1) and B (2), together with five known alkaloids, isoreserpiline, isocarapanaubine, vobasine, 10-methoxydihydrocorynantheol-N-oxide, and ochropposinine oxindole. Structural elucidation of 1 and 2 was performed using 2D NMR methods. Oppositinines A (1) and B (2) showed potent vasorelaxant effects on the rat aorta.
    Matched MeSH terms: Apocynaceae/chemistry*
  20. Hirasawa Y, Hara M, Nugroho AE, Sugai M, Zaima K, Kawahara N, et al.
    J Org Chem, 2010 Jun 18;75(12):4218-23.
    PMID: 20469917 DOI: 10.1021/jo1006762
    Two new bisindole alkaloids, bisnicalaterines B and C (1 and 2) consisting of an eburnane and a corynanthe type of skeletons, were isolated from the bark of Hunteria zeylanica. Their absolute structures were determined by combination of NMR, CD, and computational methods, and each of them was shown to be in an atropisomeric relationship. Bisnicalaterines B and C (1 and 2) showed potent vasorelaxant activity on isolated rat aorta.
    Matched MeSH terms: Apocynaceae/chemistry*
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