1-Octadecanol

Effects of Domain Size on Viscosity of alpha-Gel (alpha-Form Hydrated Crystal) Prepared from Eco-friendly Cationic Surfactant.[Pubmed:33177284]

J Oleo Sci. 2020 Dec 1;69(12):1561-1567.

We determine the effects of the alpha-gel (alpha-form hydrated crystal) domain size on the viscosity of water-diluted alpha-gels consisting of the N-[3-(dimethylamino)propyl]docosanamide (APA-22) L-lactic acid salt, 1-Octadecanol (C18OH), and water. A decrease in the C18OH mole content results in increased domain size and viscosity of the water-diluted alpha-gel system. Additionally, when a sample is prepared by slow cooling and/or at low stirring speed, the domain size and viscosity of the water-diluted alpha-gel system increase. A similar increase in the domain size and viscosity of the alpha-gel system is observed for annealed samples. The observed change in the alpha-gel domain size is explained by the crystal growth theory.

alpha-Gel (alpha-Form Hydrated Crystal) Prepared by Eco-Friendly Cationic Surfactant.[Pubmed:33055438]

J Oleo Sci. 2020 Nov 1;69(11):1403-1409.

We studied the structures and properties of gel samples prepared by mixtures of N-[3-(dimethylamino)propyl]docosanamide (APA-22) acid salt (APA-22 L-lactic acid), 1-Octadecanol (C18OH), and water. The gel samples prepared at the mole ratios [APA-22 L-lactic acid]:C18OH = 1:3, 1:4, and 1:5 yielded two phases; one being the alpha-gel (alpha-form hydrated crystal) phase, incorporating a significant quantity of water between lamellar bilayers, and the other being the excess water phase. The lamellar d-spacing remained practically unaltered at these mole ratios, thus maintaining the quantity of water incorporated between the lamellar bilayers relatively constant. Starting at 30 degrees C, the gel samples transformed into a lamellar liquid crystal phase at high temperatures (85 degrees C) and a beta-gel phase at low temperatures (5 degrees C). Interestingly, following dilution by pure water, the viscosity of the gel samples decreased with increasing C18OH content. We expect that the viscosity change affects the performance of the gel samples as hair conditioners.

Potential Anti-Acetylcholinesterase Activity of Cassia timorensis DC.[Pubmed:33020403]

Molecules. 2020 Oct 4;25(19). pii: molecules25194545.

Seventeen methanol extracts from different plant parts of five different Cassia species, including C. timorensis, C. grandis, C. fistula, C. spectabilis, and C. alata were screened against acetylcholinesterase (AChE). C. timorensis extracts were found to exhibit the highest inhibition towards AChE whereby the leaf, stem, and flower methanol extracts showed 94-97% inhibition. As far as we are aware, C. timorensis is one of the least explored Cassia spp. for bioactivity. Further fractionation led to the identification of six compounds, isolated for the first time from C. timorensis: 3-methoxyquercetin (1), benzenepropanoic acid (2), 9,12,15-octadecatrienoic acid (3), beta-sitosterol (4), stigmasterol (5), and 1-Octadecanol (6). Compound 1 showed moderate inhibition towards AChE (IC50: 83.71 muM), while the other compounds exhibited poor to slightly moderate AChE inhibitory activity. Molecular docking revealed that the methoxy substitution of 1 formed a hydrogen bond with TYR121 at the peripheral anionic site (PAS) and the hydroxyl group at C5 formed a covalent hydrogen bond with ASP72. Additionally, the OH group at the C3' position formed an interaction with the protein at the acyl pocket (PHE288). This possibly explains the activity of 1 in blocking the entry of acetylcholine (ACh, the neurotransmitter), thus impeding the hydrolysis of ACh.

Bioactivities of Allium longicuspis Regel against anthracnose of mango caused by Colletotrichum gloeosporioides (Penz.).[Pubmed:32647141]

Sci Rep. 2020 Jul 9;10(1):11367.

The present study focused on the effect of Allium longicuspis extracts (ALE) against anthracnose of mango fruit. In vitro tests (mycelial growth and conidial germination) showed that, ALE concentrated from 0.75 to 2.5 g L(-1) completely inhibited the growth of Colletotrichum gloesporioides. Cytoplasmic discharge, mycelial and conidial blasts were clearly observed when applied with ALE. The minimum effective concentration (MEC) of ALE at 0.75 g L(1) can be applied as protective, curative and simultaneous treatment in mango fruit to inhibit the anthracnose infection. Efficacy of garlic extract was relatively superior to synthetic fungicide based on protective, curative and simultaneous treatments. Twenty chemical components were detected in ALE based on GCMS analysis (Table 1). The six major components were the following: oleyl alcohol, methyl ether (42.04%), gamma-sitosterol (15.85%), , 24-norursa-3.12-diene (5.62%), 1-Octadecanol methyl ether (4.23%), n-pentadecanol (3.95%) and 2-vinyl-4h-1 3-dithiine (3.76%). The findings support the potential use of ALE as an alternative to synthetic fungicide.

Influence of the hydrophobic domain on the self-assembly and hydrogen bonding of hydroxy-amphiphiles.[Pubmed:31099371]

Phys Chem Chem Phys. 2019 Jun 7;21(21):11242-11258.

The amphiphiles 1-Octadecanol (octadecyl (stearyl) alcohol, ODA) and 1,2-dioleoylglycerol (DOG) were studied by IR spectroscopy and X-ray diffraction combined with multiscale theoretical modeling. The computations allowed us to rationalize the experimental findings and deduce the supramolecular structure of the formed assemblies while providing a fairly detailed insight into their hydrogen-bonding patterns. IR spectra revealed that the amphiphilic assemblies dramatically differ in structural order and hydrogen-bond strength, both being high in ODA and low in DOG. On the other hand, both compounds demonstrated common features, namely a splitting of the IR bands arising from O-H stretching vibrations (nuOH) as well as complete hydrophobicity. However, the observed phenomena have different origins in the two amphiphiles. While the nuOH split in ODA occurs due to a vibrational coupling along the string of inter-layer O-HO hydrogen bonds, in DOG it arises from different types of hydrogen bonds (intra- and intermolecular). The hydrophobicity of ODA stems from the very tight O-HO hydrogen bonding network connecting the opposite monolayers in a densely packed tilted crystalline phase (Lc'), whereas in DOG it occurs because the polar sites are locked inside reverted micellar-like assemblies. ODA and DOG illustrate that, in the assemblies of amphiphilic hydroxyl compounds, hydrogen bonds can be formed in a wide structural latitude, which is primarily governed by the chemical nature of apolar chains. Such a wide structural variability of OH-involving hydrogen bonds can be essential for the biological functioning of relevant molecules, such as glycolipids, acylglycerols, and, potentially, glycoproteins and carbohydrates.