The influence of the alkaloid extract of Kopsia singapurensis on the corrosion behavior of mild steel (MS) in 1 mol·L-1 HCl and 1 mol·L-1 H2SO4 was studied using electrochemical techniques, viz., potentiodyn...The influence of the alkaloid extract of Kopsia singapurensis on the corrosion behavior of mild steel (MS) in 1 mol·L-1 HCl and 1 mol·L-1 H2SO4 was studied using electrochemical techniques, viz., potentiodynamic polarization and AC impedance. The experimental results clearly show that the plant extract effectively inhibits corrosion in both acid media and the inhibition efficiency obtained from the electrochemical techniques is in good agreement. Furthermore, the polarization technique indicates that the extract acts as an anodic type inhibitor in HCl and as a mixed type in H2SO4. Scanning electron microscopy (SEM) was carried out to examine the surface morphological changes of metal specimens in both the inhibited and uninhibited solutions. SEM images show the formation of an adsorbed layer over the metal surface by the inhibitor molecule. The presence of alkaloidal constituents in the plant extract was confirmed by Fourier transform infrared (FTIR) spectroscopy and chemical analysis.展开更多
Sixteen alkaloids have been isolated from the fruits of Kopsia officinalis Tsiang and P.T. Li(Apocynaceae), a plant commonly used in folk medicine for treating tonsillitis and rheumatism. Ten of them were identified a...Sixteen alkaloids have been isolated from the fruits of Kopsia officinalis Tsiang and P.T. Li(Apocynaceae), a plant commonly used in folk medicine for treating tonsillitis and rheumatism. Ten of them were identified as known alkaloids-eburnamenine(1), kopsanone(2), 5, 18-dioxokopsan (3), kopsinilam(4), kopsinine(5), pleiocarpine(6), kopsamine(7), N-carbomethoxy-12-methoxykop- sinaline(8), N-carbomethoxy-11, 12-dimethoxykopsinaline (9) and(+)-vincadifformine (13). The other three have now been proved to be new. They are N-carbomethoxy-11-hydroxy-12-methoxy- kopsinaline(10), N-carbomethoxy-11-methoxy-12-hydroxykopsinanne (11) and kopsamine N-oxide (12).展开更多
基金supported by the USM Research Fund, Malaysia (RU-1001/229/PKIMIA/811006, FRGS-203/PKMIA/671030)
文摘The influence of the alkaloid extract of Kopsia singapurensis on the corrosion behavior of mild steel (MS) in 1 mol·L-1 HCl and 1 mol·L-1 H2SO4 was studied using electrochemical techniques, viz., potentiodynamic polarization and AC impedance. The experimental results clearly show that the plant extract effectively inhibits corrosion in both acid media and the inhibition efficiency obtained from the electrochemical techniques is in good agreement. Furthermore, the polarization technique indicates that the extract acts as an anodic type inhibitor in HCl and as a mixed type in H2SO4. Scanning electron microscopy (SEM) was carried out to examine the surface morphological changes of metal specimens in both the inhibited and uninhibited solutions. SEM images show the formation of an adsorbed layer over the metal surface by the inhibitor molecule. The presence of alkaloidal constituents in the plant extract was confirmed by Fourier transform infrared (FTIR) spectroscopy and chemical analysis.
文摘Sixteen alkaloids have been isolated from the fruits of Kopsia officinalis Tsiang and P.T. Li(Apocynaceae), a plant commonly used in folk medicine for treating tonsillitis and rheumatism. Ten of them were identified as known alkaloids-eburnamenine(1), kopsanone(2), 5, 18-dioxokopsan (3), kopsinilam(4), kopsinine(5), pleiocarpine(6), kopsamine(7), N-carbomethoxy-12-methoxykop- sinaline(8), N-carbomethoxy-11, 12-dimethoxykopsinaline (9) and(+)-vincadifformine (13). The other three have now been proved to be new. They are N-carbomethoxy-11-hydroxy-12-methoxy- kopsinaline(10), N-carbomethoxy-11-methoxy-12-hydroxykopsinanne (11) and kopsamine N-oxide (12).
文摘从海南蕊木(Kopsia hainanensis Tsiang)枝叶的乙醇提取物中分离得到7个化合物,通过波谱分析(NMR、MS、IR等),鉴定其结构分别为:蕊木宁(1)、土波台文碱(2)、二氢脱氢二松柏基醇(3)、β-香树脂醇(4)、熊果酸(5)、2α,3β-二羟基熊果酸(6)和β-谷甾醇(7)。其中化合物3～7为首次从该植物中分离得到。用滤纸片琼脂扩散法检测表明,化合物1～3和5对耐甲氧西林金黄色葡萄球菌(MRSA)生长有抑制作用;化合物2对金黄色葡萄球菌生长有抑制作用;化合物5对慢性髓原白血病细胞(K562)、人胃癌细胞(SGC-7901)和人肝癌细胞(SM M C-7721)增殖均具有细胞毒活性。
