RESUMEN
Tetrodotoxin (TTX) has been widely used in pharmacology, food poisoning analysis, therapeutic use, and neurobiology. In the last decades, the isolation and purification of TTX from natural sources (e.g., pufferfish) were mostly based on column chromatography. Recently, functional magnetic nanomaterials have been recognized as promising solid phases for the isolation and purification of bioactive compounds from aqueous matrices due to their effective adsorptive properties. Thus far, no studies have been reported on the utilization of magnetic nanomaterials for the purification of TTX from biological matrices. In this work, an effort has been made to synthesize Fe3O4@SiO2 and Fe3O4@SiO2-NH2 nanocomposites for the adsorption and recovery of TTX derivatives from a crude pufferfish viscera extract. The experimental data showed that Fe3O4@SiO2-NH2 displayed a higher affinity toward TTX derivatives than Fe3O4@SiO2, achieving maximal adsorption yields for 4epi-TTX, TTX, and Anh-TTX of 97.9, 99.6, and 93.8%, respectively, under the optimal conditions of contact time of 50 min, pH of 2, adsorbent dosage of 4 g L-1, initial adsorbate concentration of 1.92 mg L-1 4epi-TTX, 3.36 mg L-1 TTX and 1.44 mg L-1 Anh-TTX and temperature of 40 °C. Interestingly, desorption of 4epi-TTX, TTX, and Anh-TTX from Fe3O4@SiO2-NH2-TTX investigated at 50 °C was recorded to achieve the highest recovery yields of 96.5, 98.2, and 92.7% using 1% AA/ACN for 30 min reaction, respectively. Remarkably, Fe3O4@SiO2-NH2 can be regenerated up to three cycles with adsorptive performance remaining at nearly 90%, demonstrating a promising adsorbent for purifying TTX derivatives from pufferfish viscera extract and a potential replacement for resins used in column chromatography-based techniques.
RESUMEN
Two new sesquiterpene lactones, laurenolide A (1) and laurenolide B (2), along with six known compounds, palmitic acid (3), (R,R)-hexahydrofarnesyl acetone (4), trans-phytol acetate (5), cholesterol (6), cholesteryl acetate (7), cholesteryl heptadecanoate (8) were isolated from Palisada intermedia. The chemical structures of all compounds were elucidated by 1D and 2D-NMR spectroscopy and HR-ESI-MS analysis as well as compared with data in the literature. The petroleum ether, chloroform, ethyl acetate, methanol extracts and compounds 1, 2 were tested for the inhibition of two cancer cell lines MCF-7, NCI-H460 and they showed weak or none activities.
RESUMEN
Phytochelatins (PCs), the heavy metal-binding peptides of plants, play a main function in heavy metal detoxification. In this study, Enhalus acoroides samples collected at six distinct seagrass beds from the coast of Khanh Hoa province, Viet Nam, were evaluated for their PCs. The contents of different PCs in each organ including leaf, rhizome, and root were determined by using HPLC analysis. Significant differences of PC2 contents among specific organs and their relation were tested by ANOVA, Tukey test, and Pearson's correlation. The results showed that higher PC2, appearance of PC3 and a strong correlation between PC2 and Pb concentration were found in the root organ collected from a Pb contaminated area. We conclude that high Pb in the sediment induce high PC2 and PC3 production in the root. This first report on in situ detection of PCs of seagrass encourages future investigation on the ability to use seagrass for phytoremediation and as a bioindicator of heavy metals based on PC contents.
