Cytotoxicity of the natural herbicidal chemical, berberine, on Nicotiana tabacum Bright yellow-2 cells.

Berberine is a naturally occurring plant secondary metabolite with allelopathic and cytotoxic properties. We investigated the cytotoxic effects of berberine against tobacco Bright Yellow-2 (BY-2) cells. We found that berberine inhibited tobacco BY-2 cell growth in a concentration-dependent manner and the potency of berberine was comparable to the traditional herbicide glyphosate. Meanwhile, the in vivo test revealed that the herbicidal activity of berberine was also comparable to that of glyphosate. Further mechanism studies for the cytotoxicity demonstrated that berberine at concentrations of 40 µg/mL and 80 µg/mL induced cell death by causing mitochondrial membrane depolarization, irregular nuclei and chromatin condensation but not leading to significant apoptosis. Ultra-structure analysis through transmission electron microscopy (TEM) indicated that treatments with 40 µg/mL berberine for 2 d or 80 µg/mL berberine for 1 d induced cell damage, including nuclei morphological changes, cytoplasm and mitochondria degradation and cell wall fibrosis. Treatment at higher concentration of 80 µg/mL for longer period of 2 d, induced plasmolysis and severe damage to basic cell structure, which are indicative of explosive necrosis. Our results suggest that berberine was cytotoxic to tobacco BY-2 cells by inducing necrosis but not apoptosis. Cell wall, mitochondria, nuclei and chromatin were damaged and may be possible primary targets. Therefore, the herbicidal activity of berberine appears to be a complex process associated with multiple mechanisms of action.

Cytotoxicity of chemical constituents from Torricellia tiliifolia DC. on Spodoptera litura (SL-1) cells.

In this study, we evaluated cytotoxicity of chemicals isolated from Torricellia tiliifolia DC. on Spodoptera litura (SL-1) cell line. Among the isolated compounds, 4-hydroxy-3-methoxycinnamaldehyde, 3,5-dimethoxy-4-hydroxycinnamaldehyde, and syringaresinol inhibited SL-1 cell survival in both dose- and time-dependent manners. Meanwhile, the in vivo insecticidal activity test revealed that 4-hydroxy-3-methoxycinnamaldehyde and 3,5-dimethoxy-4-hydroxycinnamaldehyde showed obvious insecticidal activities. These two compounds exhibited toxicity to SL-1 cells by inducing cellular morphological changes including shape change, cell shrinkage, vacuolation, cell membrane blebbing and chromatin condensation and apoptosis. 4-hydroxy-3-methoxycinnamaldehyde and 3,5-dimethoxy-4-hydroxycinnamaldehyde showed the most effect on mitochondrial membrane depolarization at 24h and 72h respectively and induced the apoptosis at a late time point 72h. Our results suggest that 4-hydroxy-3-methoxycinnamaldehyde and 3,5-dimethoxy-4-hydroxycinnamaldehyde inhibit SL-1 survival by inducing apoptosis.

Rotenone alpha-oxime.

The structure determination of the title compound, rotenone alpha-oxime [systematic name: 1,2,12,12a-tetrahydro-8,9-dimethoxy-2-(1-methylethenyl)-[1]benzopyrano[3,4-b]furo[2,3-h][1]benzopyran-6(6H)-one oxime], C(23)H(23)NO(6), confirms that the molecule has an approximately V-shaped structure. One of the rings has a typical cyclohexene-like monoplanar conformation and the central ring adopts a 1,2-diplanar conformation.