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In our antioxidant screening of some Vietnamese plant extracts, the CHCl3-soluble fraction from Calotropis gigantea (L.) W.T.Aiton flowers showed moderate DPPH free radical scavenging activity with an IC50 value of 55.8 μg/mL. Thus, a further phytochemical study was carried out to obtain five alkaloids, including a new β-carboline-type alkaloid, caloside H (1). These known compounds were identified as 5-hydroxy-(2-methoxymethyl)pyridine (2), nicotinic acid (3), p-(acetylamino)phenol (4), and thymine (5). These structures were determined based on the NMR spectroscopic analysis. In antioxidant assay, caloside H at concentration of 100 μM showed DPPH radical scavenging capacity with a percentage of inhibition of 40.2%. In addition, a plausible biosynthetic pathway for the formation of caloside H was proposed based on the Schiff base formation and Mannich-like reaction. [ABSTRACT FROM AUTHOR]

Bioactivity-guided isolation of the CHCl3-soluble fraction of the stems of Salacia chinensis L. (Celastraceae) was carried out to obtain a new 7′,9-epoxylignan (1) and three 7,9′:7′,9-diepoxylignans (2–4). The absolute configuration of 1 was elucidated based on NMR and ECD spectroscopic data interpretation. All isolated lignans showed intermediate α-glucosidase inhibitory activity with the IC50 values ranging from 28.5 to 85.6 µM. [ABSTRACT FROM AUTHOR]

From an EtOAc-soluble fraction of the stem barks of Swintonia floribunda (Anacardiaceae), one new dimeric alkylresorcinol named integracin E (1), together with 4 known compounds (2–5) were isolated. Their chemical structures were elucidated based on the spectroscopic data interpretation. The absolute configuration of 1 was determined by the specific rotation analysis of its acid-catalyzed hydrolysis product. Compound 1 showed potent tyrosinase inhibitory activity with an IC50 value of 48.2 μM. [ABSTRACT FROM AUTHOR]

From an CHCl3-soluble fraction of the stems of Semecarpus caudata, one new bischromanone named semecarpanone (1), together with 5 known flavonoids (2'6) were isolated. Their structures were elucidated based on interpretation of spectroscopic data. The stereo-configuration of 1 was identified based on the calculated and experimental coupling constants. Compounds 4'6 showed potent tyrosinase inhibitory activity with the IC50 values ranging from 15.0 to 76.3 μM. [ABSTRACT FROM AUTHOR]

The aim of this study was to estimate the costs of treatment of children who present with the signs and symptoms of invasive bacterial diseases in Khanh Hoa province, Viet Nam. The study was an incidence-based cost-of-illness analysis from the health system perspective. The hospital costs included labour, materials and capital costs, both direct and indirect. Costs were determined for 980 children, with an average age of 12.67 months (standard deviation +/- 11.38), who were enrolled in a prospective surveillance at the Khanh Hoa General Hospital during 2005-2006. Of them, 57% were male. By disease-category, 80% were suspected of having pneumonia, 8% meningitis, 3% very severe disease consistent with pneumococcal sepsis, and 9% other diseases. Treatment costs for suspected pneumonia, meningitis, very severe disease, and other diseases were US$ 31, US$ 57, US$ 73, and US$ 24 respectively. Costs ranged from US$ 24 to US$ 164 across different case-categories. Both type of disease and age of patient had statistically significant effects on treatment costs. The results showed that treatment costs for bacterial diseases in children were considerable and might differ by as much as seven times among invasive pneumococcal diseases. Changes in costs were sensitive to both age of patient and case-category. These cost-of-illness data will be an important component in the overall evidence base to guide the development of vaccine policy in Viet Nam. [ABSTRACT FROM AUTHOR]