Antistaphylococcal activity of Inula helenium L. root essential oil: eudesmane sesquiterpene lactones induce cell membrane damage

Abstract

The purpose of this study was to investigate the inhibitory/bactericidal activity and cell membrane effects of the hydrodistilled essential oil of Inula helenium L. roots against Staphylococcus aureus. Additionally, detailed chemical investigation was done in order to pinpoint the most active oil constituents and also the parts of these molecules responsible for their antimicrobial effect. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined using the broth microdilution method. The membrane-active nature of this oil was investigated by measuring the culture turbidity, leakage of phosphates, and 260-nm-absorbing material, together with lysis of the exposed cells. Finally, the effect of the oil on the cells was visualized using scanning electron microscopy (SEM). The chemical composition of the essential oil was analyzed using gas chromatography-mass spectrometry (GC-MS) and preparative medium-pressure liquid chromatography (MPLC). Chemical modification of the oil was performed using catalytic hydrogenation (H(2), Pd/C) and reduction with NaBH(4). The MIC and MBC values were 0.01 μl mL(-1) and 0.02 μl mL(-1), respectively. Membrane damage was demonstrated through increased permeability (phosphates and nucleic acid leakage), followed by lysis of the exposed cells, captured on SEM images. The most active constituents were alantolactone, isoalantolactone, and diplophyllin. The essential oil showed very potent antistaphylococcal activity, with obvious membrane-damaging effects. Sesquiterpene lactones were found to be the most active principles of the oil, whose eudesmane core olefinic bonds, along with the α,β-methylene-lactone ring, are essential structural parts responsible for the exhibited antimicrobial activity.

Inhibitory Effect of Herbal Remedy PERVIVO and Anti-Inflammatory Drug Sulindac on L-1 Sarcoma Tumor Growth and Tumor Angiogenesis in Balb/c Mice

“…Essential oils from Litsea cubeba contain fungicidal and antibacterial terpenoids [42, 43]. Sesquiterpene lactones from Inula helenium root essential oil exhibited antistaphylococcal activity [44]. …”

Mechanism-based inhibition of Alantolactone on human cytochrome P450 3A4 in vitro and activity of hepatic cytochrome P450 in mice

“…Alantolactone (AL) (PubChem CID: 72724), as an active ingredient, has mainly been isolated from I. helenium L. plants Khan et al, 2012;Lim et al, 2007). AL shows various biological effects, including anthelmintic, antifungal (Tan et al, 1998;Tripathi et al, 1988), anti-inflammatory (Chun et al, 2012;Schmidt et al, 2002), antimicrobial (Stojanovic-Radic et al, 2012;Xin et al, 2008), and anti-proliferative effects on several cancer cell lines, such as prostate, ovary, colon, and leukemia (Konishi et al, 2002;Pal et al, 2010). However, most studies pay attention to pharmacological effects of AL and no study of its effects on CYPs has been conducted.…”

Metabolism Analysis of Alantolactone and Isoalantolactone in Rats by Oral Administration

“…Current literature shows that alantolactone and isoalantolactone possess various antimicrobial [3], antiinflammatory [4], and antitumor activities [5][6][7][8][9][10] both in vivo and in vitro. A recent study done by the team revealed that alantolactone and isoalantolactone could significantly relieve irritable bowel syndrome (IBS) by regulating neurotransmitters, gastrointestinal hormones, and intestine propulsive movement.…”