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A phytochemical investigation of methanol extract from leaves of Pachyrhizus erosus (L.) Urban, a leguminous shrub distributed in Vietnam and other tropical and subtropical countries led to the isolation of a new prenylated chalcone, erosusone (1) and a new megastigmane glycoside epimer, 3-episedumoside F1 (9), together with thirteen known compounds including flavonoids (2-6), a 3-benzoxepine lactone (7), a pyridine-4,5-diol derivative (8), megastigmanes and megastigmane glycosides (10-15). Their structures were elucidated by means of high resolution-electrospray ionization (HR-ESI)-MS, one dimensional (1D) and two-dimensional NMR (2D-NMR) spectroscopy as well as comparison with the data reported in the literature. The cytotoxic effects on LU-1 (lung carcinoma), HepG2 (hepatocellular carcinoma), and MCF7 (breast carcinoma) cell lines were assessed. Prenylated chalcones 1-2 and isoflavone 3 exhibited cytotoxicity against all tested cell lines with IC50 values ranging from 22.04 to 45.03 µM.

Soybean (Glycine max (L) Merr.) is one of the major crops grown worldwide for human food and animal feed. Nanotechnology is one of the most potential tools in modern agriculture to improve crop productivity. In this paper, we investigated the effect of single and mixture cobalt nanoparticles on the change of photosynthesis - related parameters and antioxidant enzyme activity of soybean Glycine max (L) Merr “DT26” at different growth stages under pilot scale. The results showed that all form of cobalt nanoparticles treatment enhanced the photosynthesis of soybean by increasing the content of chlorophyll a, Pn and the ratio of Fv/Fm. These values tended to increase and reached the maximum value at fifth trifoliate stage and then decreased at the beginning bloom stage. The activity of antioxidant enzymes such as superoxide dismutase and peroxidase (when seeds were treated with USA single colbalt nanoparticles at concentration of 16.67 mg/kg) and catalase (with USA single colbalt nanoparticles at concentration of 0.17 mg/kg) were increased in 2.11, 1.85 and 1.60 times respectively compared to the control group (without the treatment of colbalt nanoparticles) while ascorbate peroxidase was reached highest value (increased in 2.73 times) under the condition of Vietnam single colbalt nanoparticles at the dose of 0.17 mg/kg seeds. This suggests that cobalt nanoparticles treatment has generated oxidative stresses and soybean DT26 has the self-protection mechanism by increasing the activity of antioxidant enzymes in order to reduce the amount of H2O2 and O2 which accumulates in the leaf cells.

Marine microalga Isochrysis sp. was isolated from Hai Phong area of Vietnam coastal zone. Their pure cultures were raised in the laboratory for culture optimization, molecular identification and biochemical analysis. Based on the morphological studies the newly isolated species was identified as Isochrysis galbana Parke and was confirmed by 18S rRNA gene analysis. The nucleotide sequence of partial 18S rRNA gene was submitted to the GENEBANK with accession number FJ536744. Optimum conditions for growth of the species was f/2 medium at temperature 25 ± 1°C, salinity 30 ± 1 psu, pH 7.0 and light intensity of 100 μmol m−2 s−1. Under these optimum conditions, the content of protein, carbohydrate and total lipid were 27.981 ± 0.892%, 25.263 ± 0.789% and 9.780 ± 0.120% of dry cell weight, respectively (equivalent 38.768 ± 0.892%, 35.000 ± 0.789% and 13.550 ± 0.120% of ash free dry weight). I. galbana Parke, strain HP has the highest content of docosahexanenoic acid (DHA), up to 14.7% of total fatty acid and maximal polyunsaturated fatty acids (PUFAs) values at the early stationary phase in f/2 medium. The n-3 and n-6 PUFA ratio (n-3/n-6) of strain HP was from 4.50 to 5.69 at different phases of growth curve. These results suggest that biomass of this strain can be used as live feed in aquaculture.

The heterotrophic marine microalga, Schizochytrium mangrovei PQ6, synthesizes large amounts of polyunsaturated fatty acids (PUFAs) with possible nutritional applications. We characterized the transcriptome of S. mangrovei PQ6, focusing on lipid metabolism pathways throughout growth. Cell growth, total lipid, and docosahexaenoic acid (DHA, 22:6n-3) contents of S. mangrovei PQ6 in 500 ml batch cultures rapidly increased on day 1 in cultivation and reached their maximum levels on day 5. Maximum lipid accumulation in 500 ml batch cultures occurred on day 5, with total lipid and DHA contents reaching 33.2 ± 1.25% of dry cell weight (DCW) and 136 mg/g DCW, respectively. 11,025 unigenes, 28,617 unigenes and 18,480 unigenes from the transcriptomes of samples collected on day 1, 3, and 5 in cultivation were identified, respectively. These unigenes of the three samples were further assembled into 30,782 unigenes with an average size of 673 bp and N50 of 950 bp, and a total of 9,980 unigenes were annotated in public protein databases. 93 unigenes involved in lipid metabolism in which expression patterns corresponded with total lipid and DHA accumulation patterns were identified. The possible roles of PUFAs pathways, such as those mediated by fatty acid synthase, polyketide synthase, and desaturase/elongase, co-exist in S. mangrovei PQ6.

Schizochytrium sp. PQ6, a heterotrophic microalga isolated from Phu Quoc (PQ) Island in the Kien Giang province of Vietnam, contains a high amount of docosahexaenoic acid (DHA, C22:6n-3). In this study, the culture conditions are developed to maximize biomass and DHA production. Nucleotide sequence analysis of partial 18S rRNA gene from genomic DNA showed that PQ6 has a phylogenetic relationship close to Schizochytrium mangrovei Raghu-Kumar. The highest growth rate and DHA accumulation of this strain were obtained in 6.0% glucose, 1.0% yeast extract, 50% artificial seawater (ASW), and pH 7 at 28°C. In addition, carbon and nitrogen sources could be replaced by glycerol, ammonium acetate, sodium nitrate, or fertilizer N-P-K. Total lipid content reached 38.67% of dry cell weight (DCW), in which DHA and eicosapentaenoic acid (EPA, C20:5n-3) contents accounted for 43.58% and 0.75% of the total fatty acid (TFA), respectively. In 5 and 10 L fermenters, the cell density, DCW, total lipid content, and maximum DHA yield were 46.50 × 10(6) cells · mL(-1) , 23.7 g · L(-1) , 38.56% of DCW, and 8.71 g · L(-1) (in 5 L fermenter), respectively, and 49.71 × 10(6) cells · mL(-1) , 25.34 g · L(-1) , 46.23% of DCW, and 11.55 g · L(-1) (in 10 L fermenter), respectively. Biomass of PQ6 strain possessed high contents of Na, I, and Fe (167.185, 278.3, and 43.69 mg · kg(-1) DCW, respectively). These results serve as a foundation for the efficient production of PQ6 biomass that can be used as a food supplement for humans and aquaculture in the future.