Ruimin Mu

The Algicidal Characteristics of One Algae-Lysing FDT5 Bacterium on Microcystis aeruginosa

One strain of algicidal bacterium which can inhibit Harmful algal blooms (HABs), FDT5, was isolated from activated sludge and found to have good algicidal effects on Microcystis aeruginosa. It was revealed that: The FDT5 was a Gram-negative bacterium and identified as Ochrobactrum sp.; The greater the initial bacterial cell density, the faster the degradation of chlorophyll a.; The algicidal efficiency was evaluated at the most favorable conditions which were a temperature of 30–35°C, a pH of 7.6 and complete darkness; The FDT5 strain lysed Microcystis aeruginosa not directly but by secreting metabolites which could withstand high temperatures and pressure.

A SIMPLE, FAST, SOLVENT-FREE METHOD FOR THE DETERMINATION OF VOLATILE COMPOUNDS IN MAGNOLIA GRANDIFLORA LINN

Magnolia grandiflora Linn belonging to the Magnoliaceae family has been used to treat hypertension for many years in China. Based on microwave-assisted extraction (MAE) and headspace solid-phase microextraction (HS-SPME) followed by gas chromatography-mass spectrometry (GC-MS), the volatile compounds of Magnolia grandiflora L. were determined. Results indicated that the optimum conditions of the determination of the volatile compounds in Magnolia grandiflora L. were achieved with fiber coating of carboxen/polidimethylsiloxane, microwave power of 700 W and irradiation time of 4 min. Under the optimal conditions, for the first time, 48 volatile compounds were separated and identified from the fresh leaves of Magnolia grandiflora L. The highest content component of 48 compounds was γ-elemene (15.67%). Relative standard deviation (RSD) values less than 11% shows that the present method has good precision. The experimental results demonstrate that MAE-HS-SPME followed by GC-MS is a simple, time-saving solvent-free method, and it is a potential analytic tool for the determination of the volatile compounds in plant materials.

Chemical composition of volatile constituents of Magnolia grandiflora

Magnolia grandiflora Linn, native to North America, is an immense broad-leaved evergreen of the Magnoliaceae family [1]. As one of the traditional Chinese medicines (TCMs), the leave of Magnolia grandiflora L. has been applied to the treatment of hypertension for many years in China. Many volatile constituents with bioactivity are present in its leave [2]. Therefore, understanding the chemical composition of volatile constituents in the leave of Magnolia grandiflora L. is an essential step in using it more scientifically. In this short communication, for the first time, volatile constituents of Magnolia grandiflora L. were extracted by headspace solid-phase microextraction (HS-SPME) combined with microwave-assisted extraction (MAE) and then analyzed by gas chromatography-mass spectrometry (GC-MS) for the fast determination of volatile constituents [3, 4]. Compared with conventional extraction such as hydrodistillation, steam distillation, Soxhlet extraction, and so on, HS-SPME can evidently improve the extraction efficiency and it is also a time-saving, simple, and solvent-free method.

Chemical composition of the volatile compounds of Cinnamomum septentrionale

Cinnamomum septentrionale Hand.-Mazz. is a medium or large tree of the Lauraceae family, native of China, grown in the valley or on the hillside. Camphor, which is used as analgetic in medicine or perfume for preventing insect and antisepsis, can be produced by distilling its root. We isolated volatile and active compounds from plant material by microwave distillation (MD), which was developed by Chemat and co-workers [1], followed with headspace solid-phase microextraction (HS-SDME) introduced by Jeannot and Cantwell [2]. The sample was heated by a microwave at the power of 400 W for 4 min [3]. Gas chromatography-mass spectrometry (GC-MS) was used to study the volatile compounds of Cinnamomum septentrionale Hand.-Mazz., and the total amount of components was 99.144%. The compositions of the volatile compounds of Cinnamomum septentrionale Hand.-Mazz. are shown in Table 1. The main constituents were 3-tert-pentylcyclopentanone (71.899%), 3,7-dimethyl-2,6-octadienal (4.412%), hexadecane (2.844%), camphor (2.734%), borneol (2.494), α-farnesene (1.801%), 3-carene (1.563%), β-neoclovene (1.189%), and α-pinene (1.101%).