Difference in Anti-microbial Activity of Propan-1,3-diol and Propylene Glycol

Abstract

Propan-1,3-diol (PD) and propan-1,2-diol (propylene glycol, PG) are very similar compounds because their structures, safety data, and anti-microbial activities are almost the same. Actually, both compounds are made up of three carbon atoms and two hydroxyl groups. Regarding their safety, they do not have serious hazard data for animals, and LD 50 values (in rats) of both are similar. As for the anti-microbial activity, minimum inhibitory concentration (MIC) values of both PD and PG are approximately 10% (v/v). In this study, we used the preservatives-effectiveness test (PET) to evaluate the anti-microbial activities of PD and PG, because both compounds are used in cosmetics as preservatives. The results indicated that PD was more effective as an anti-microbial agent compared with PG, and the effect of PD was marked against Escherichia coli and Pseudomonas aeruginosa. Scanning electron microscopy (SEM) images showed that the membrane of Escherichia coli was injured by PD and PG, but the damage by PD was more marked. The damage of the cell membrane may be the cause of high anti-microbial activity of PD in PET. These results suggest that PD has greater potential as a preservative, and PD should be recommended as an additive for food and medicine.

Total Synthesis of the Proposed Structure of Indolyl 1,2-Propanediol Alkaloid, 1-(1H-Indol-3-yloxy)propan-2-ol

“…An initial screen of Brønsted acids resulted in decomposition, probably due to the presence of free alcohol. After intensive screening of Brønsted and Lewis acids (BF 3 •OEt 2 , AlCl 3 , ZnCl 2, FeCl 2 , InCl 3 , InBr 3 , In(OTf) 3 , and Yb(OTf) 3 ), we observed that BF 3 •OEt 2 in AcOEt/MeCN generated the desired alkoxyindole 7 and 3 as a regioisomeric mixture (1.0:1.1) at a 50% yield [50]. The change in the diastereomeric ratio from 1.0:1.9 (5:6) to 1.0:1.1 (7:3) suggested that the demethoxylative aromatization of 5 and 6 occurred through cyclic intermediates such as a spiroketal intermediate 4 ′ , which permitted the reaction through a stabilized oxonium ion.…”

“…All substrates were used as received from commercial suppl Aldrich, Tokyo, Japan; Kanto Chemical, Tokyo, Japan; TCI, Tokyo, Japan; an kyo, Japan) and all reagents were weighed and handled in air at room temp work-up and purification steps were carried out with reagent-grade solvents 2.1. Synthesis of N-Tosylindoles (2) [51]: N-Tosylindoles (2) Was Prepared by a Rep Method [50] 1 H NMR (400 MHz, CDCl3) δ: 8.00 (ddd, J = 8.3, 1.8, 1.2 Hz, 1H), 7.77 (d 2H), 7.57 (d, J = 3.6 Hz, 1H), 7.53 (ddd, J = 7.7, 1.2, 0.8 Hz, 1H), 7.32 (ddd, J = Hz, 1H), 7.23 (ddd, J = 7.6, 6.8, 1.2 Hz, 1H), 7.22 (d, J = 8.0 Hz, 2H), 6.66 (dd, J = 1H), 2.34 (s, 3H); 13 Potential biological activity in combination with unprecedented indolyl saccharide bearing 1,2-propandiol makes 1-(1H-indol-3-yloxy)propan-2-ol (1) an attractive synthetic target for medicinal and synthetic chemistry. However, the structure of 1 was determined by 2D-NMR and MS analyses, while neither of its [α]D data nor absolute configurations were presented.…”

“…All work-up and purification steps were carried out with reagent-grade solvents in air. [51]: N-Tosylindoles (2) Was Prepared by a Reported Method [50] 1 H NMR (400 MHz, CDCl 3 ) δ: 8.00 (ddd, J = 8.…”

“…It has an unprecedented 1,2-propandiol moiety at the C3 position of indole. Furthermore, 1,2-propandiol possesses anti-microbial activity, and is used as a preservative agent in pharmaceuticals and food [50].…”