Effect of 13-epi-Sclareol on the Bacterial Respiratory Chain

Abstract

13-epi-sclareol is a labdane-type diterpene isolated from the resinous exudates of the medicinal plant species Pseudognaphalium cheiranthifolium (Lam.) Hilliard et Burtt. and P. heterotrichium (Phil.) A. Anderb. This compound has antibacterial activity only against Gram-positive bacteria, showing a bactericidal and lytic action. The interaction of 13- epi-sclareol with the bacterial respiratory chain was analyzed. The compound inhibited oxygen consumption of intact Gram-positive cells, but not with Gram-negative bacteria. The compound inhibited NADH oxidase and cytochrome c reductase activities, while coenzyme Q reductase and the cytochrome c oxidase activities were not affected. These results suggest that the target site of 13-epi-sclareol is located between coenzyme Q and cytochrome c. Using cytoplasmic membrane fractions, the results of the analysis of the enzyme activities associated with the respiratory chain complexes were the same for both Gram-positive and Gram-negative bacteria, indicating that the compound has no access to the cytoplasmic membrane of intact Gram-negative bacteria. Thus, the Gram-negative envelope may act as a physical barrier that prevents the access of this compound to the site of action.

Characterization of the Antifungal Activity Against Botrytis Cinerea of Sclareol and 13-Epi-Sclareol, Two Labdane-Type Diterpenoids

“…Different results were obtained in Gram positive bacteria treated with 13-epi-Sclareol 21 Tapia et al (2004) reported that this compound inhibited oxygen consumption in intact Gram-positive. In addition, the authors described that the diterpenoid was able to inhibit NADH oxidase and cytochrome C reductases activities suggesting that the target site of 13-epi-Sclareol was located between coenzyme Q and cytochrome C of the bacterial respiratory chain 21 .…”

“…In addition, the authors described that the diterpenoid was able to inhibit NADH oxidase and cytochrome C reductases activities suggesting that the target site of 13-epi-Sclareol was located between coenzyme Q and cytochrome C of the bacterial respiratory chain 21 .…”

Antimicrobial activities and mode of action of the selected novel thienopyrimidines derivatives 2-[2-(diphenylmethylene) hydrazino]-5-isopropyl-3-methylthieno [2, 3-d] pyrimidin-4-one

“…This effect may be indicates that many chemical compounds interfering directly with electron transfer or uncoupled oxidative phosphorylation from electron transport. So, the aerobic synthesis of ATP is inhibited and the oxygen uptake is not inhibited (17). Also, it may be indicates a slight effect on the plasma membrane and increasing cells respiration for exhausting the energy compound present inside the cell before its death (20).…”

“…The quantity of oxygen consumed by the living cells (respiratory activity) in the presence or absence of the sublethal dose of the thienopyrimidine compound was determined as described by Tapia et al (17). The living cells of the tested bacterial species and fungi grown up to exponential phase were harvested by centrifugation (6000 g), washed with saline solution and resuspended to a concentration of one mg/mL cells (wet weight) in 50 mM phosphate buffer (pH 7.0).The cell suspension was added to a two mL chamber.…”

Stimulating Effect of Sclareol on Suicidal Death of Human Erythrocytes

“…Plant-derived terpenoids [1] such as the diterpene alcohol Sclareol [2] are effective against cancer [1,[3][4][5][6][7][8][9][10][11][12][13], inflammation [1,14,15], and infection [16][17][18]. Sclareol further influences brain function [19][20][21][22][23][24][25].…”