Apoptosis by 6-O-palmitoyl-l-ascorbic acid coincides with JNK-phosphorylation and inhibition of Mg2+-dependent phosphatase activity

Molecular docking and antibacterial activity of Sargassum fusiforme extracts against major coral pathogens

The present study evaluates the antibacterial properties of alkaloids and the crude extracts (ethanol, n-hexane and ethyl acetate) from seaweed Sargassum fusiforme against coral pathogens (Photobacterium galatheae, Vibrio harveyi, Bordetella trematum, and Ochrobactrum pseudogrignonese) isolated from coral Porites lutea. To our knowledge, this is the first in vitro assay for such extracts on Porites lutea coral pathogens. Bacterial pathogens have been identified using 16S RNA and BankIt into gene bank and given the accession numbers (OR401000; OR401001; OR401336, and OR400998 respectively). GC-Mass profiling conducted for n-hexane compounds confirmed the presence of thirty-eight molecules, twelve of which have been previously reported for their bioactivity. The results revealed that alkaloids and n-hexane extract demonstrated eminent antibacterial activity compared to the other extracts against the tested coral pathogenic bacteria. Molecular docking was conducted to evaluate the twelve previously mentioned bioactive molecules to get a full understanding of the interaction of those bioactive molecules on vital bacterial proteins (Hemolysin protein (PDB ID: 1XEZ) and Cytoplasmic proteins (PDB ID: 3TZC)). Docked twelve molecules against hemolysin protein (PDB ID: 1XEZ) came exactly in line with the docked result of the same molecules with cytoplasmic proteins (PDB ID: 3TZC), proving the bioactivity of 6-O-Palmitoyl-L-ascorbic acid, 3TMS derivative; Glycerol monostearate, 2TMS derivative and Eicosanoic acid complexes in antibacterial activity action and score higher than reference ligand. Those three compounds will be investigated separately in future in vitro assay soon. Our conclusions align with the study's antibacterial in vitro assay results. The present study reports the novelty of different extracts of S. fusiforme as an antibacterial agent against coral pathogenic bacteria that trigger diseases in Porites lutea.

Comparison of the rapid pro-apoptotic effect of trans-ß-nitrostyrenes with delayed apoptosis induced by the standard agent 5-fluorouracil in colon cancer cells

Trans-beta-nitrostyrene (TBNS) has been reported to be a potent inhibitor of protein phosphatases PTB1 and PP2A and to display a pro-apoptotic effect even in multidrug resistant tumour cells. Here we compared the anti-tumour potential of TBNS with 5-fluorouracil (5-FU) as the standard chemotherapeutic agent for colorectal cancer in LoVo cells. Resistance to 5-FU based therapy might be a consequence of 5-FU's delayed effect requiring long-term effective concentrations in the tumour tissue. Thus, alternatives like platin containing drugs with a more rapid effect have been introduced recently. Compared to 5-FU TBNS displayed a faster cytotoxic and pro-apoptotic effect. A 50% decrease in viability was observed already after 8 h with TBNS while 5-FU displayed no significant effect before 48 h. DNA fragmentation and caspase-3 assays confirmed the more rapid apoptotic effect of TBNS. Since apoptosis affects individual cells these results about a rapidly induced apoptosis were further studied on a single cell level in microscopic assays of caspase-3 and caspase-8 activation. Adducts of trans-beta-nitrostyrene displayed an anti-tumour effect comparable to TBNS which suggests the possibility of creating adducts with optimised tissue targeting. Finally, the calculation of a drug combination index displayed a synergistic effect for the combination of TBNS and 5-FU in Lovo as well as in HT-29 and HCT116 colon cancer cells.