Fasihuddin B. Ahmad

Physico-chemical characterisation of sago starch

The physico-chemical characteristics of various sago starch samples from South East Asia were determined and compared to starches from other sources. X-ray diffraction studies showed that all the sago starches exhibited a C-type diffraction pattern. Scanning electron microscopy showed that they consist of oval granules with an average diameter around 30 μm. Proximate composition studies showed that the moisture content in the sago samples varied between 10.6% and 20.0%, ash between 0.06% and 0.43%, crude fat between 0.10% and 0.13%, fiber between 0.26% and 0.32% and crude protein between 0.19% and 0.25%. The amylose content varied between 24% and 31%. The percentage of amylose obtained by colourimetric determination agreed well with the values obtained by fractionation procedures and potentiometric titration. Intrinsic viscosities and weight average molecular weight were determined in 1M KOH. Intrinsic viscosity for amylose from sago starches varied between 310 and 460 ml/g while for amylopectin the values varied between 210 and 250 ml/g. The molecular weight for amylose was found to be in the range of 1.41×106 to 2.23×106 while for amylopectin it was in the range of 6.70×106 to 9.23×106. The gelatinisation temperature for the sago starches studied varied between 69.4°C and 70.1°C. The exponent ‘a’ in the Mark–Houwink equation and the exponent ‘α’ in the equation Rg=kMα was found to be 0.80 and 0.58, respectively for amylose separated from sago starch and these are indicative of a random coil conformation. Two types of pasting properties were observed. The first was characterised by a maximum consistency immediately followed by sharp decrease in consistency while the second type was characterised by a plateau when the maximum consistency was reached.

Medicinal Plants of Sabah, East Malaysia – Part I

This paper provides a brief account of 50 plants species used by Kadazan/Dusun communities in Sabah, Malaysia, as traditional herbal medicines. Many of the uses were new when compared with published literature on ethnomedicine in Malaysia and neighboring New Guinea, Philippines and Indonesia.

Inhibitory effect of compounds from Goniothalamus tapis Miq. and Goniothalamus uvaroides King on platelet-activating factor receptor binding.

Phytochemical investigation on the bark of Goniothalamus tapis Miq. and G. uvaroides King has resulted in the isolation of eight styryl‐lactones, (−)‐cryptomeridiol, liriodenine, 3‐methyl‐1H‐benz[f]indole‐4,9‐dione, (−)‐stigmasterol and dimethyl terephthalate. The structures of the compounds were elucidated by spectroscopic techniques. The compounds were evaluated for their effect on platelet‐activating factor (PAF) receptor binding on rabbit platelets using 3H‐PAF as a ligand. Among the compounds tested, (−)‐cryptomeridiol, (+)‐goniothalamin and (+)‐isoaltholactone exhibited a significant and concentration‐dependent inhibitory effect on PAF receptor binding, with inhibitory concentration (IC)50 values of 17.5, 19.7 and 46.5 µm, respectively. The inhibitory effects of the first two compounds were comparable to that obtained from the positive control, cedrol. The results indicated that these compounds were strong PAF receptor binding inhibitors. Copyright

Organotin(IV) complexes with pyruvic acid phenylhydrazone (HPAPD): synthesis, spectral characterization, and in vitro antibacterial activity

The reaction of pyruvic acid phenylhydrazone [HPAPD, (1)] with organotin(IV) chloride(s) leads to the formation of five new organotin(IV) complexes: [MeSnCl2(PAPD)] (2), [BuSnCl2(PAPD)] (3), [PhSnCl2(PAPD)] (4), [Me2SnCl(PAPD)] (5), and [Ph2SnCl(PAPD)] (6). The ligand [HPAPD, (1)] and its organotin(IV) complexes (2–6) have been characterized by CHN analyses, molar conductivity, UV-Vis, FT-IR, 1H, 13C, and 119Sn NMR spectral studies. Spectroscopic data suggested that HPAPD is coordinated to tin(IV) through the carboxylato-O and azomethine-N as a mononegative bidentate chelating agent; the coordination number of tin is five. Compound 1 and its organotin(IV) complexes (2–6) were assayed for in vitro antibacterial activity against Staphylococcus aureus, Bacillus subtilis, Enterobacter aerogenes, Escherichia coli, and Salmonella typhi. The screening results show that 2–6 have better antibacterial activity than 1 and that 6 exhibits significantly better activity than 2–5.

Medicinal Plants of Sabah, Malaysia, Part II. The Muruts

AbstractINTRODUCTIONThe Murut people of Borneo island are found in the northeast of Sarawak and the soutwest of Sabah, especially in the Tenom, Keningau and Pensiangan areas. Murut is derived from “murut-urut”, meaning moving around - refering to their semi-nomadic way of life. Some Muruts are lowland dwellers, where they grow swamp-padi (wet rice), maize, and tapioca. Muruts often live in long houses, originally built on ridges above rivers for protection. Today they usually inhabit valleys, close to rivers.

Synthesis, characterization, and antibacterial activity of organotin(IV) complexes with 2-hydroxyacetophenone thiocarbohydrazone

Six new organotin(IV) complexes were synthesized by direct reaction of RSnCl3 (R = Me, Bu and Ph) or R2SnCl2 (R = Me, Bu and Ph) and 2-hydroxyacetophenone thiocarbohydrazone [H2APTC] under purified nitrogen in the presence of base in 1 : 2 : 1 molar ratio (metal: base: ligand). Complexes 2–7 have been characterized by elemental analyses, molar conductivity, UV-Visible, IR and 1H NMR spectral studies. Complexes 2–7 are non-electrolytes. The molecular structure of [Me2Sn(APTC)] · (C2H5OH) (5) has been determined by X-ray diffraction analysis. The thiocarbohydrazone ligand (1) and 2–7 have been tested for antibacterial activity against Escherichia coli, Staphylococcus aureus, Salmonella typhi and Enterococci aeruginosa.

Synthesis, characterization, antibacterial, and cytotoxic activities of organotin(iv) complexes derived from n (4)-cyclohexylthiosemicarbazone: x-ray crystal structure of [ph 2sncl(l)]

Reaction of organotin(IV) chloride(s) with 2-benzoylpyridine-N(4)-cyclohexylthiosemicarbazone, [HL] (1) yielded [MeSnCl2(L)] (2), [BuSnCl2(L)] (3), [Me2SnCl(L)] (4), and [Ph2SnCl(L)] (5). The ligand (1) and its organotin(IV) complexes have been characterized by CHN analyses, molar conductivity, UV-Vis, FT-IR, 1H, 13C, and 119Sn NMR spectral studies. The molecular structure of 5 was also determined by X-ray diffraction. There are two independent molecules in the asymmetric unit and the central tin(IV) atom is six-coordinate in distorted octahedral geometry. The ligand (1) and complexes were screened for their in vitro antibacterial activities. The cytotoxic activities of 1–5 were tested against A2780 and A2780/Cp8 cancer cell lines. The compounds have better antibacterial activities than the free ligand; 2–5 are more potent cytotoxic agents than 1, while the diphenyltin(IV) 5 is more active with IC50 values of 0.05 and 0.54 µmol L−1 against A2780 and A2780/Cp8 cell lines, respectively.

Synthesis and characterization of tin(IV)/organotin(IV) complexes with 2-benzoylpyridine-N(4)-cyclohexylthiosemicarbazone [HBPCT]: X-ray crystal structure of [SnCl3(BPCT)]

Four new tin(IV)/organotin(IV) complexes, [SnCl3(BPCT)] (2), [MeSnCl2(BPCT)] (3), [Me2SnCl(BPCT)] (4), and [Ph2SnCl(BPCT)] (5), have been synthesized by the direct reaction of 2-benzoylpyridine-N(4)-cyclohexylthiosemicarbazone [HBPCT, (1)] and stannic chloride/organotin(IV) chloride(s) in absolute methanol under purified nitrogen. HBPCT and its tin(IV)/organotin(IV) complexes (2–5) were characterized by CHN analyses, molar conductivity, UV-Vis, FT-IR, and 1H NMR spectral studies. In all the complexes, tin(IV) was coordinated via pyridine-N, azomethine-N, and thiolato-S from 1. The molecular structure of 2 has been determined by X-ray single-crystal diffraction analysis. Complex 2 is a monomer and the central tin(IV) is six-coordinate in a distorted octahedral geometry. The crystal system of 2 is monoclinic with space group P121/n1 and the unit cell dimensions are a = 8.3564(3) Å, b = 23.1321(8) Å, c = 11.9984(4) Å.

Synthesis, Characterization and In Vitro Antibacterial Studies of Organotin(IV) Complexes with 2-Hydroxyacetophenone-2-methylphenylthiosemicarbazone (H2dampt)

Five new organotin(IV) complexes of 2-hydroxyacetophenone-2-methylphenylthiosemicarbazone [H(2)dampt, (1)] with formula [RSnCl(n-1)(dampt)] (where R = Me, n = 2 (2); R = Bu, n = 2 (3); R = Ph, n = 2 (4); R = Me(2), n = 1 (5); R = Ph(2), n = 1 (6)) have been synthesized by direct reaction of H(2)dampt (1) with organotin(IV) chloride(s) in absolute methanol. The ligand (1) and its organotin(IV) complexes (2-6) were characterized by CHN analyses, molar conductivity, UV-Vis, FT-IR, (1)H, (13)C, and (119)Sn NMR spectral studies. H(2)dampt (1) is newly synthesized and has been structurally characterized by X-ray crystallography. Spectroscopic data suggested that H(2)dampt (1) is coordinated to the tin(IV) atom through the thiolate-S, azomethine-N, and phenoxide-O atoms; the coordination number of tin is five. The in vitro antibacterial activity has been evaluated against Staphylococcus aureus, Enterobacter aerogenes, Escherichia coli, and Salmonella typhi. The screening results have shown that the organotin(IV) complexes (2-6) have better antibacterial activities and have potential as drugs. Furthermore, it has been shown that diphenyltin(IV) derivative (6) exhibits significantly better activity than the other organotin(IV) derivatives (2-5).

Effect of dextran on the thermal and rheological properties of sago starch

Publisher Summary This chapter explains the effect of the presence of dextran on the thermal and rheological properties of sago starch. The gelation properties of starch is reported to be enhanced by the presence of polysaccharides with higher hot paste viscosities and storage moduli having been reported compared to starch alone. The increase in the storage moduli for corn starch in the presence of guar, LBG and xanthan is attributed to phase separation due to incompatibility of the starch and the added polysaccharides. Furthermore, phase separation is also reported for wheat starch systems In the presence of gelatin, iota-carrageenan, xanthan, kappa-carrageenan and low methoxy pectin. The presences of polysaccharides have been shown tolittle effect on the gelatinization temperature or the gelatinization enthalpy of starch. Differential scanning calorimetry shows that the gelatinization process shifts to slightly higher temperatures and becomes much broader when the dextran concentration exceeds 10%. On standing at 45 °C for 48hours, phase separation is observed above a critical total polysaccharide concentration of ∼7%. It also explains the starch gelation does not occur at dextran concentrations >1% and this is attributed to inhibition of amylose leaching and phase separation.