Size-transformable nanohybrids with pH/redox/enzymatic sensitivity for anticancer therapy.

A lack of sufficient tumor penetration and low delivery efficiency are the main reasons for the limited clinical applications of nanocarriers in cancer treatment. Tumor microenvironment responsive drug delivery systems have been attracting great interest in cancer therapy as the desired drug release can be achieved in the disease sites for optimal treatment efficiency. In this work, we developed a biodegradable nanohybrid drug delivery system with pH/redox/enzymatic sensitivity by the simple assembly of bovine serum albumin nano-units (about 5 nm) onto graphene oxide nanosheets in the presence of a naturally originating protein (gelatin). The nanoparticles can maintain a constant size under physiological conditions, while releasing 5 nm nano-units containing the drug upon triggering by the environment-mimicking protease highly expressed in the tumor microenvironment. Furthermore, after reaching the tumor tissue, the acidic, reductive, and enzymatic microenvironments turned on the switch for DOX release, and the combination of chemotherapy and photothermal therapy was achieved under the trigger of near-infrared light. The nanosystems have the potential to improve the penetration ability through the depth of the tumor tissue to enhance drug intracellular delivery and antitumor bioactivity.

Programmed cell death of Chlamydomonas reinhardtii induced by three cyanobacterial volatiles ß-ionone, limonene and longifolene.

ß-Ionone, limonene and longifolene are 3 main components in cyanobacterial volatile organic compounds, which are formed through different pathways and can poison and even kill other algae. To uncover their toxic mechanism from programmed cell death (PCD), the photosynthetic pigments, chlorophyll fluorescence, caspase-like activities, cell size, nuclear variations and DNA ladders were investigated in Chlamydomonas reinhardtii treated with ß-ionone (0.2 mM), limonene (0.2 mM) and longifolene (0.4 mM) at lethal concentration during 24 h. In the treatments with the 3 compounds, the photosynthetic pigments in C. reinhardtii cells gradually degraded, and Fv/Fm gradually decreased and disappeared at 24 h, suggesting that the cell death might be a PCD, due to the physiological activities gradually disappearing. During the cell death, the activities of caspase-9-like and caspase-3-like significantly increased, with the highest at 1 h. With prolonging the treatment time, C. reinhardtii cells gradually shrank, and the nuclei concentrated firstly following by a broken process, with moving to the cell edge. For DNA, obvious ladders were detected at 1 h, and then they gradually degraded to fragments of 100-250 bp at 24 h. These hallmarks suggested that ß-ionone, limonene and longifolene may poison other algae by inducing PCD.

Kaempferol separated from Camellia oleifera meal by high-speed countercurrent chromatography for antibacterial application.

Natural biologically active substances have received continuous attention for the potentially beneficial health properties against chronic diseases. In this study, bacteriostatic active substance from Camellia oleifera meal, which is a major by-product of the Camellia oil processing industry, were extracted with continuous phase change extraction (CPCE) method and separated by HSCCC. Compared with traditional extraction methods, CPCE possessed higher extraction efficiency. Two main substances were separated and purified (above 90.0%). The structure of them were further identified by UV, LC-ESI-MS-MS, 1H-NMR, and 13C-NMR as flavonoids F2 kaempferol 3-O-[ß-d-glucopyranosyl-(1 → 2)-α-l-rhamnopyranosyl-(1 → 6)]-ß-d-glucopyranoside and J2 kaempferol 3-O-[ß-d-xylopyranosyl-(1 → 2)-α-l-rhamnopyranosyl-(1 → 6)]-ß-d-glucopyranoside for the first time in C. Oleifera meal. The results of antibacterial activity measurement showed that both compounds have excellent antibacterial activity. And the antibacterial stability of F2 were finally confirmed: F2 showed broad spectrum antibacterial activity against Escherichia coli, Staphylococcus aureus, Salmonella enteriditis, Bacillus thuringiensis, Aspergillus niger and Rhizopus nigricans. Besides, F2 exhibited relatively high stable property even at high temperature, acid and metal ion solutions. The findings of this work suggest the possibility of employing C. oleifera meal as an attractive source of health-promoting compounds, and at the same time facilitate its high-value reuse and reduction of environmental burden.