Weiyao Hu

Three new anthraquinones from the twigs of Cassia fistula and their bioactivities

Abstract Three previously unreported anthraquinones, fistulaquinones A–C (1–3), together with three known ones (4–6) were isolated from the twigs of Cassia fistula. Their structures were determined by means of extensive NMR and MS spectroscopic analyses. All the isolated compounds were tested for their anti-tobacco mosaic virus (anti-TMV) activity, and compound 3 showed significant activity with inhibition rate of 34.5% at 20 μM concentration, even more potent than positive control. Additionally, compounds 1–6 exhibited moderate cytotoxicity with IC50 values ranging from 2.8 to 9.4 μM for some tested human tumor cell lines.

Anti-Tobacco Mosaic Virus Isocoumarins from the Leaves of Nicotiana tabacum

Two new isocoumarins, tabaisocoumarins D and E (1 and 2), together with two known isocoumarins (3 and 4), were isolated from the leaves of Nicotiana tabacum. The structures of 1–4 were elucidated by spectroscopic methods, including extensive 1D and 2D NMR techniques. Compounds 1–4 were also tested for their anti-tobacco mosaic virus (anti-TMV) activities. Compounds 1–4 exhibited anti-TMV activities with inhibition rates in the range of 11.2–17.5%.

Effects of tourmaline on growth of three kinds of microorganisms

Tourmaline is a kind of widespread minerals and has been used in many fields of society. Owing to the special electric properties, tourmaline can destroy the hydrogen bond between water molecules. The growth of microorganism may be affected with addition of tourmaline; therefore the effects of tourmaline on three different kinds of microorganisms were studied using microcalorimetric method. The kinetic parameters of growth process were obtained through the thermogenic curves. The results show that high concentration tourmaline inhibited the growth of prokaryotic cells (the growth rate constant of Escherichia coli and Staphylococcus aureus decreased 68.77 and 35.25% at tourmaline concentration of 160 g/L), while promoted eukaryotic cell (the growth rate constant of Candida albicans increased 40.73% at tourmaline concentration of 160 g/L). However, the low concentration tourmaline had complex effects on growth of the studied microorganisms. Key words: Microcalorimetric, water cluster, growth rate, inhibitory ratio.