Improving the Antioxidant Properties of Calophyllum inophyllum Seed Oil from French Polynesia: Development and Biological Applications of Resinous Ethanol-Soluble Extracts

Tamanu oil from Calophyllum inophyllum L. has long been used in traditional medicine. Ethanol extraction was found the best strategy for recovering bioactive compounds from the resin part of Tamanu oil, yielding two neutral and acidic resins fractions with high phenolics, flavonoids and pyranocoumarins concentrations. A further cascade of LPLC/HPLC separations of neutral and acidic resin fractions allowed identifying fifteen metabolites, and among them, calanolide D and 12-oxocalanolide A (both in neutral fraction) were first identified from a natural source. All these extracts, subfractions and isolated metabolites demonstrated increased free radical scavenging, antioxidant, anti-inflammatory, antimicrobial and antimycobacterial activity compared to Tamanu oil and its de-resinated lipid phase. Overall, these results could promote resinous ethanol-soluble Tamanu oil extracts as a useful multifaceted and renewable medicinal resource.

Antioxidative Activity of 1,3,5-Triazine Analogues Incorporating Aminobenzene Sulfonamide, Aminoalcohol/Phenol, Piperazine, Chalcone, or Stilbene Motifs

A series of 1,3,5-triazine analogues, incorporating aminobenzene sulfonamide, aminoalcohol/phenol, piperazine, chalcone, or stilbene structural motifs, were evaluated as potential antioxidants. The compounds were prepared by using step-by-step nucleophilic substitution of chlorine atoms in starting 2,4,6-trichloro-1,3,5-triazine. Reactions were catalyzed by Cu(I)-supported on a weakly acidic resin. The radical scavenging activity was determined in terms of %inhibition activity and EC50, using the ABTS method. Trolox and ascorbic acid (ASA) were used as standards. In the lowest concentration 1 × 10−4 M, the %inhibition activity values at 0 min were comparable with both standards at least for 10 compounds. After 60 min, compounds 5, 6, 13, and 25 showed nearly twice %inhibition (73.44–87.09%) in comparison with the standards (Trolox = 41.49%; ASA = 31.07%). Values of EC50 at 60 min (17.16–27.78 μM) were 5 times lower for compounds 5, 6, 13, and 25 than EC50 of both standards (trolox = 178.33 μM; ASA = 147.47 μM). Values of EC50 correlated with %inhibition activity. Based on these results, the presented 1,3,5-triazine analogues have a high potential in the treatment of illnesses caused or related to oxidative stress.

New 1,3,5-Triazine Derivatives Incorporating Aminobenzenesulfonamide, Aminoalcohol, Piperazine, Chalcone or Stilbene Structural Motifs and Evaluation of Their Antioxidative Activity

A series of 1,3,5-triazine derivatives, incorporating aminobenzenesulfonamide, aminoalcohol/phenol, piperazine, chalcone, or stilbene structural motifs, were evaluated as potential antioxidants. The compounds were prepared by using step by step nucleophilic substitution of chlorine atoms in starting 2,4,6-trichloro-1,3,5-triazine. Reactions were catalyzed by Cu(I)-supported on a weakly acidic resin. The radical scavenging activity was determined in terms of %inhibition activity and IC50, using the ABTS method. Trolox and ascorbic acid (ASA) were used as standards. In the lowest used concentration 1 × 10−4 M, the %inhibition activity at time 0 min was comparable with both standards at least for 10 compounds. After 60 min compounds 1, 2, 9 and 25 showed nearly twice %inhibition (73.44–87.09%) in comparison with standards (Trolox = 41.49%; ASA = 31.07%). Values of IC50 correlated with %inhibition activity. For compounds 1, 2, 9 and 25 values of IC50 in time 60 min (17.16–27.78 μM) were 5 times lower than IC50 of both standards (Trolox = 178.33 μM; ASA = 147.47 μM). Based on these results, the presented 1,3,5-triazine derivatives and their analogs have a high potential in the treatment of illnesses caused or related to oxidative stress.

Gel-Type and Macroporous Cross-Linked Copolymers Functionalized with Acid Groups for the Hydrolysis of Wheat Straw Pretreated with an Ionic Liquid

Several sulfonated cross-linked copolymers functionalized with hydroxyl and carboxylic groups have been synthesized. The amount of the cross-linking monomer was tailored (from 4% up to 40%) to tune the resulting micro- and nano-morphologies, and two types of catalysts, namely, gel-type and macroreticular catalysts, were obtained. These copolymers were employed in the catalytic hydrolysis of wheat straw pretreated in 1-ethyl-3-methylimidazolium acetate to obtain sugars. Remarkably, the presence of additional oxygenated groups enhances the catalytic performances of the polymers by favoring the adsorption of β-(1,4)-glucans and makes these materials significantly more active than an acidic resin bearing only sulfonic groups (i.e., Amberlyst 70). In addition, the structure of the catalyst (gel-type or macroreticular) appears to be a determining factor in the catalytic process. The gel-type structure provides higher glucose concentrations because the morphology in the swollen state is more favorable in terms of the accessibility of the catalytic centers. The observed catalytic behavior suggests that the substrate diffuses within the swollen polymer matrix and indirectly confirms that the pretreatment based on dissolution/precipitation in ionic liquids yields a substantial enhancement of the conversion of lignocellulosic biomass to glucose in the presence of heterogeneous catalysts.

Green cyclic acetals production by glycerol etherification reaction with benzaldehyde using cationic acidic resin

In this paper, we investigated the effect of temperature, glycerol etherification concentration with benzaldehyde, organic solvent and catalyst reuse effects using a cationic acidic resin as catalyst for production of green cyclic acetals of high commercial value. The best reaction conditions show a conversion above 93% of glycerol and yield to cyclic acetals above 61%. The highest selectivity elements observed were 2-phenyl-1,3-dioxan-5-ol, in cis and trans isomer forms reaching 80%. The temperature had a positive effect increasing on glycerol conversion, though it also favored the formation of undesired compounds. A high concentration of benzaldehyde reactant kept the selectivity values constant but increased glycerol conversion resulting in higher yields, mainly when organic solvents were used. Reuse of the catalyst resulted in a slight decrease in yield values, which demonstrated stability and durability of the catalyst used.

Etherification of Glycerol with C4 and C5 Reactive Olefins

In this study etherification of glycerol, with C4 (isobutylene) and C5 (2 Methyl 2 Butene) olefins was investigated for the production of transportation fuel additives. The etherification reactions were carried out in a stainless steel autoclave reactor. Activities of acidic resin catalysts, Amberlyst-36, Dowex DR-2030 and Dowex M-31 were compared. Especially in the absence of any published work for the investigations of experimental conditions on glycerol conversion and product distributions in etherification of glycerol with C5 (2 Methyl 2 Butene) olefin results obtained with C4 and C 5 olefins are quite promising.