Papers by Hidayat Hussain
Natural Product Research, Jan 1, 2005
Two new myrsinol-type diterpene polyesters 3,5,13,17-tetra-O-acetyl-7-O-benzoyl-15-hydroxymyrsino... more Two new myrsinol-type diterpene polyesters 3,5,13,17-tetra-O-acetyl-7-O-benzoyl-15-hydroxymyrsinol (1) and 3,5,13,17-tetra-O-acetyl-7-O-butanoyl-13-hydroxymyrsinol (2), with a tricyclic carbon skeleton have been isolated from Euphorbia decipiens Boiss. & Buhse. The structure elucidation of the isolated compounds was based primarily on HREIMS, EIMS, IR, UV, ID-, and 2D-NMR analyses, including COSY, HMQC, HMBC, and NOESY correlations. Compounds 1 and 2 also showed activity against urease enzyme.
Phytotherapy Research, Jan 1, 2007
During the course of screening of medicinal plants of Pakistan for the isolation and structure el... more During the course of screening of medicinal plants of Pakistan for the isolation and structure elucidation of bioactive natural products, it was found that the methanol extract of the Rhododendron collettianum showed analgesic and spasmolytic activities. The methanol extract was then extracted with chloroform. Nine pentacyclic triterpenes were isolated from the chloroform extract and their structures were elucidated as erythrodiol (1), betulinic acid (2), maslinic acid (3), 2α,3α,23-trihydroxyolean-12-en-28-oic acid (4), bayogenin (5), arjunilic acid (6), methyl arjunolate (7), arjungenin (8) and 3β, 23, 24-trihydroxyolean-12-en-28-oic acid (9). Among the triterpenes (1–9) tested, arjunilic acid (6) was found to be most potent. Their structure–activity relationship (SAR) showed that if the configuration of the –OH group at C-2 is changed from α to β the potency is decreased. In most of the compounds the position and configuration of the –OH group was found to be important for the inhibitory potency against the enzyme tyrosinase. For the comparison, the standard tyrosinase inhibitors kojic acid (IC50 = 16.67 µm) and l-mimosine (IC50 = 3.68 µm) were used as controls. Copyright © 2007 John Wiley & Sons, Ltd.
Organic Letters, Jan 1, 2009
Chiral enamides, easily prepared in one step from a cyclic ketone and an oxazolidinone, are succe... more Chiral enamides, easily prepared in one step from a cyclic ketone and an oxazolidinone, are successfully employed in high-yielding, endo, and facially selective Hetero-Diels-Alder reactions involving activated oxadienes and Siever's reagent as catalyst. From the resulting bicyclic heteroadducts, a novel and efficient asymmetric modification for the Robinson annulation of cyclic monoketones is described.
Variables that affect the magnitude of the magnetic fields in distribution line system are the ma... more Variables that affect the magnitude of the magnetic fields in distribution line system are the magnitude of the distribution lines' phase currents, the distance of the distribution lines from the observation points, the conductors' configurations, and the ground currents due to unbalanced phase current. By using the delta type and the horizontal type of 33 kV primary overhead distribution poles as models, this paper presents the case studies of the effect of that variables to the primary overhead distribution lines and proposes the design options such as increasing the height of the distribution lines, increasing the lateral distance from the distribution lines, compacting the lines conductors' spacing, minimizing the ground current by balancing the lines' phase currents, and optimizing phasing arrangement. Another design criteria such as cost, safety, reliability, system stability, etc. also need to be considered before the design options recommended can be applied
Biochemical Systematics and Ecology, Jan 1, 2009
The user has requested enhancement of the downloaded file. This article appeared in a journal pub... more The user has requested enhancement of the downloaded file. This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.
Cheminform, Jan 1, 2008
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was e... more ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Fitoterapia, Jan 1, 2005
One myrsinol-type diterpene ester (1) isolated from Euphorbia decipiens was evaluated for analges... more One myrsinol-type diterpene ester (1) isolated from Euphorbia decipiens was evaluated for analgesic activity in the acetic acid induced writhing test in mice. Different dose (5–20 mg/kg i.p.) of the compound showed significant antinociceptive activity, which was comparable to standard analgesic drugs, aspirin and ibuprofen (100 mg/kg i.p.).
Cheminform, Jan 1, 2009
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was e... more ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Biochemical Systematics and Ecology, Jan 1, 2007
Endophytic fungi have proven to be a rich source of novel organic compounds with interesting biol... more Endophytic fungi have proven to be a rich source of novel organic compounds with interesting biological activities and a high level of structural diversity (Dai et al., 2005; Schulz and Boyle, 2005). As a part of our systematic search for new bioactive lead structures from endophytic fungi (Hussain et al., 2007; Krohn et al., 2007), the endophytic fungus Acremonium sp. isolated from Plantago lancelota, was cultured for isolation of metabolites. Similarly, an unidentified Ascomycete, isolated from Erica arborea, was selected for ...
Heterocycles, Jan 1, 2007
Abstract–A unique highly substituted chromone dimer, named exochromone (1a), in addition to the k... more Abstract–A unique highly substituted chromone dimer, named exochromone (1a), in addition to the known steroids ergosterol (2) and 5α, 8α-epidioxyergosterol (3) were isolated from endophytic fungus Exophiala sp. The structure of the new compound was elucidated on the basis of spectroscopic data. Preliminary studies showed that exochromone is antifungal and antialgal against Microbotryum violaceum and Chlorella fusca, respectively.
Tetrahedron-asymmetry, Jan 1, 2007
The absolute configuration of 1β,10β-epoxydesacetoxymatricarin 1, a sesquiterpenoid isolated from... more The absolute configuration of 1β,10β-epoxydesacetoxymatricarin 1, a sesquiterpenoid isolated from Carthamus oxycantha, was established by TDDFT CD calculations in combination with single crystal X-ray analysis. Since the solid-state CD spectrum shows contributions from intermolecular interactions in the crystal, 1 represents a test case for our solid-state CD/TDDFT approach.1β,10β-EpoxydesacetoxymatricarinC15H18O4[α]D20=+26.0 (c 0.16, CH2Cl2)
Cheminform, Jan 1, 2007
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was e... more ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
European Journal of Organic Chemistry, Jan 1, 2009
Abstract Six new metabolites, namely cycloepoxylactone (1a), cycloepoxytriol A (2), cycloepoxytri... more Abstract Six new metabolites, namely cycloepoxylactone (1a), cycloepoxytriol A (2), cycloepoxytriol B (3) and phomolactones A–C (4–6), were isolated from two cultures of the ethyl acetate soluble fraction of the endophytic fungus Phomopsis sp.(internal strain no. 7233). Their structures were determined by means of spectroscopic data including HREIMS, 1 H NMR, 13 C NMR, and 2D NMR (HMQC, HMBC, and NOESY). The absolute configurations of 1a, 4 and 5 were determined by circular dichroism and comparison of ...
Magnetic field spot measurements were done at four distribution substations, three of them were o... more Magnetic field spot measurements were done at four distribution substations, three of them were of exactly the same design and capacity, while the fourth has similar design and half the capacity. The data collected were compared with one another. Taking into account loading of the substation during measurement period, it was found that magnetic field distributions were similar, with high peaks at low voltage cable connections to transformers and low-voltage switchgears. Magnetic fields decayed rapidly with distance. Magnetic field longitudinal and transverse linear plots crossing the middle of the substations were also constructed and these were also found to be similar. Magnetic field parameter plots give information of magnetic field of which the general public may likely be exposed to. These were found to be lower than the limit recommended by the most standards.
Tetrahedron-asymmetry, Jan 1, 2007
Two metabolites, the known antitumor macrolide hypothemycin 1 and its new 5′-O-methyl ether, 5′-O... more Two metabolites, the known antitumor macrolide hypothemycin 1 and its new 5′-O-methyl ether, 5′-O-methylhypothemycin 2, and the known steroid ergosterol 3, were isolated from a Phoma sp. The structures were elucidated by means of spectroscopic data analysis, and the absolute configuration of hypothemycin 1 was confirmed by single crystal X-ray analysis in combination with the new solid-state CD/TDDFT methodology. Since the solid-state CD spectrum shows contributions from intermolecular interactions in the crystal, 1 represents a critical test case for our solid-state CD/TDDFT approach.HypothemycinC19H22O8[α]D20=+18 (c 0.50, CHCl3)5′-O-Methylhypothemycin 2C20H24O8[α]D20=+21.0 (c 0.50, CHCl3, 5% CH3OH)
Chemical & Pharmaceutical Bulletin, Jan 1, 2007
Two new prenylated anthraquinones, laurenquinone A (1) and B (2) were isolated from the seeds of ... more Two new prenylated anthraquinones, laurenquinone A (1) and B (2) were isolated from the seeds of Vismia laurentii together with four known compounds; xanthone V(1) (3), physcion (4), 3-geranyloxyemodin anthrone (5) and friedelin (6). The structures of the new metabolites were determined with the help of spectroscopic data including extensive 2D-NMR spectroscopy. The known compounds were identified by comparison of their physical and spectroscopic data with those reported in the literature. Compounds 1, 4 and 5 exhibited moderate algicidal activity against Chlorella fusca and 3 showed moderate activity against the gram-positive bacterium Bacillus megaterium.
Chemistry-a European Journal, Jan 1, 2009
Chemical & Pharmaceutical Bulletin, Jan 1, 2005
Newbouldiaquinone (1), a new naphthoquinone-anthraquinone coupled pigment and a new ceramide name... more Newbouldiaquinone (1), a new naphthoquinone-anthraquinone coupled pigment and a new ceramide named newbouldiamide (2), have been isolated from Newbouldia laevis, besides the known compounds lapachol (3), canthic acid, oleanolic acid, 2-methyl-9,10-anthracenedione, 2-acetylfuro-1,4-naphthoquinone, 2,3-dimethoxy-1,4-benzoquinone, 2-(4-hydroxyphenyl)ethyl triacontanoate, beta-sitosterol and beta-sitosterol glucopyranoside. The structure elucidations of the isolated new compounds were performed on the basis of spectroscopic and chemical evidence. Preliminary studies showed that 1 is moderately antibacterial against Gram-positive Bacillus megaterium and that 3 has moderate herbicidal and antibacterial activities.
Chemical & Pharmaceutical Bulletin, Jan 1, 2003
Three new diterpene esters with a myrsinol-type skeleton have been isolated from Euphorbia decipi... more Three new diterpene esters with a myrsinol-type skeleton have been isolated from Euphorbia decipiens BOISS. & BUHSE. The structure elucidation of the isolated compounds was based primarily on two-dimensional (2D)-NMR techniques including correlation spectroscopy (COSY), heteronuclear multiple quantum coherence (HMQC), heteronuclear multiple bond correlation (HMBC) and nuclear Overhauser effect spectroscopy (NOESY) experiments. Compounds 1 and 3 are active against prolyl endopeptidase and compound 2 showed inhibitory activity against urease enzyme.
Botanica Marina, Jan 1, 2008
Abstract To determine the best sources of novel, biologically active metabolites, both endophytic... more Abstract To determine the best sources of novel, biologically active metabolites, both endophytic fungi (plant isolates) and fungi associated with algae were isolated from plants and algae from marine habitats of the North, Baltic and Mediterranean Seas, Atlantic Ocean, and Gulf of Mexico. Following preselection of the isolates according to taxon and metabolic profiles, almost all were active in at least one of the tests for antibacterial, antifungal, and/or herbicidal activities. Metabolites isolated from the culture extracts belonged to diverse ...
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Papers by Hidayat Hussain