Sesterterpenes and phenolic alkenes from the Thai sponge Hyrtios erectus

Sesterterpene, erectusolide A (1), six phenolic alkenes, erectuseneols A?F (2–7) and nine known compounds, luffalactone (8), luffariolide E (9), (6E)- and (6Z)-neomanoalide 24,25-diacetates (10 and 11), 6,6-dimethylundecane-2,5,10-trione (12), threo- and erythro-cavernosines (13 and 14), (4E,6E)-dehydromanoalide (15), echinoclerodane A (16), were isolated from the marine sponge Hyrtios erectus. Compound 13 was isolated for the first time from a natural source. The structures of these compounds were elucidated on the basis of spectroscopic analysis. The phenolic alkenes 3 and 7, the sesterterpenes 8–11 and 15, and compounds 12–14 were evaluated for cytotoxic activities against six cancer cell lines, MOLT-3, HepG2, HeLa, HuCCA-1, A549, and MDA-MB-231.     

Iodo–sesquiterpene hydroquinone and brominated indole alkaloids from the Thai sponge Smenospongia sp.

6′-Iodoaureol, an iodo–sesquiterpene hydroquinone, 6′-aureoxyaureol, a bissesquiterpene hydroquinone, and four brominated indole alkaloids 3–6 were isolated from the Thai sponge Smenospongia sp. Additionally, four known sesquiterpene hydroquinones 12–15, ten known brominated indole alkaloids 7–11, 17–18, and 20–22, ergosterol, and furospinosulin-1 were also isolated. Compound 1 is the first reported iodo–sesquiterpene hydroquinone and compounds 7–11 were isolated for the first time from natural sources. The structures were characterized by spectroscopic analyses as well as comparison with literature data. Several of these metabolites were evaluated for cytotoxic activity against seven tumor cell lines.     

Effect of carboxymethyl cellulose concentration on physical properties of biodegradable cassava starch-based films

Background  

Cassava starch, the economically important agricultural commodity in Thailand, can readily be cast into films. However, the cassava starch film is brittle and weak, leading to inadequate mechanical properties. The properties of starch film can be improved by adding plasticizers and blending with the other biopolymers.     

High Substitution Synthesis of Carboxymethyl Chitosan for Properties Improvement of Carboxymethyl Chitosan Films Depending on Particle Sizes

This study investigated the effect of chitosan particle sizes on the properties of carboxymethyl chitosan (CMCh) powders and films. Chitosan powders with different particle sizes (75, 125, 250, 450 and 850 µm) were used to synthesize the CMCh powders. The yield, degree of substitution (DS), and water solubility of the CMCh powders were then determined. The CMCh films prepared with CMCh based on chitosan with different particle sizes were fabricated by a solution casting technique. The water solubility, mechanical properties, and water vapor transmission rate (WVTR) of the CMCh films were measured. As the chitosan particle size decreased, the yield, DS, and water solubility of the synthesized CMCh powders increased. The increase in water solubility was due to an increase in the polarity of the CMCh powder, from a higher conversion of chitosan into CMCh. In addition, the higher conversion of chitosan was also related to a higher surface area in the substitution reaction provided by chitosan powder with a smaller particle size. As the particle size of chitosan decreased, the tensile strength, elongation at break, and WVTR of the CMCh films increased. This study demonstrated that a greater improvement in water solubility of the CMCh powders and films can be achieved by using chitosan powder with a smaller size.