Insights into the Relationships Between Herbicide Activities, Molecular Structure and Membrane Interaction of Cinnamon and Citronella Essential Oils Components

Since the 50’s, the massive and “environmental naïve” use of synthetic chemistry has revolutionized the farming community facing the dramatic growth of demography. However, nowadays, the controversy grows regarding the long-term harmful effects of these products on human health and the environment. In this context, the use of essential oils (EOs) could be an alternative to chemical products and a better understanding of their mode of biological action for new and optimal applications is of importance. Indeed, if the biocidal effects of some EOs or their components have been at least partly elucidated at the molecular level, very little is currently known regarding their mechanism of action as herbicides at the molecular level. Here, we showed that cinnamon and Java citronella essential oils and some of their main components, i.e.,, cinnamaldehyde (CIN), citronellal (CitA), and citronellol (CitO) could act as efficient herbicides when spread on A. thaliana leaves. The individual EO molecules are small amphiphiles, allowing for them to cross the mesh of cell wall and directly interact with the plant plasma membrane (PPM), which is one of the potential cellular targets of EOs. Hence, we investigated and characterized their interaction with biomimetic PPM while using an integrative biophysical approach. If CitO and CitA, maintaining a similar chemical structure, are able to interact with the model membranes without permeabilizing effect, CIN belonging to the phenylpropanoid family, is not. We suggested that different mechanisms of action for the two types of molecules can occur: while the monoterpenes could disturb the lipid organization and/or domain formation, the phenylpropanoid CIN could interact with membrane receptors.

Differing disintegration and dissolution rates, pharmacokinetic profiles and gastrointestinal tolerability of over the counter ibuprofen formulations

OBJECTIVES

Formulations of over the counter (OTC) NSAIDs differ substantially, but information is lacking on whether this alters their gastrointestinal profiles. To assess disintegration and dissolution rates and pharmacokinetics of four preparations of OTC ibuprofen and relate these with spontaneously reported gastrointestinal adverse events.

METHODS

Disintegration and dissolution rates of ibuprofen tablets as (a) acid, (b) sodium salt, (c) lysine salt, and (d) as a liquid gelatine capsule were assessed. Pharmacokinetic data gastrointestinal and spontaneously reported adverse events arising from global sales were obtained from files from Reckitt Benckiser.

KEY FINDINGS

Disintegration at low pH was progressively shorter for the preparations from a-to-d with formation of correspondingly smaller ibuprofen crystals, while dissolution was consistently poor. Dissolution at a neutral pH was least rapid for the liquid gelatine capsule. Pharmacokinetic data showed a shorter t_max and a higher C_max for preparations b-d as compared with ibuprofen acid. Spontaneously reported abdominal symptoms were rare with the liquid gelatine preparation.

CONCLUSIONS

The formulations of OTC ibuprofen differ in their disintegration and dissolution properties, pharmacokinetic profiles and apparent gastrointestinal tolerability. Spontaneously reported abdominal symptoms were five times lower with the liquid gelatine capsule as compared with ibuprofen acid despite a 30% increase in C_max .

Potent analogues of etiprednol dicloacetate, a second generation of soft corticosteroids

OBJECTIVES

Loteprednol etabonate (LE) is the first, highly successful soft corticosteroid (SC) designed using the 'inactive metabolite' approach, starting with ∆¹ -cortienic acid (d-CA). The next generation of SCs based on d-CA was etiprednol dicloacetate (ED). The 17α-dichloroacetyl function serves both as a unique pharmacophore and as the source of the molecule's softness. Highly potent SCs were designed based on a combination of ED and LE, introducing 6, 9 and 16 substituents in the molecule.

METHODS

The new 6α, 9α, 16α and β 17α-dichloroacetyl 17β-esters were synthesized from the correspondingly substituted ∆¹ -cortienic acids. The anti-inflammatory activity was assessed using LPS-induced TNF α-release under various conditions to determine intrinsic activity vs. systemic biological stability. In vivo anti-inflammatory activity was studied in the widely used ovalbumin-sensitized and ovalbumin-challenged Brown Norway rat model.

KEY FINDINGS

The 6α or 9α-fluoro substitution produced highly potent corticosteroids, but the 17α-dichloroacetyl substituent provided 'softness' in all cases. Local application of these steroids will significantly reduce systemic activity, due to the facile hydrolytic deactivation of these molecules.

CONCLUSIONS

A 17α-dichloroacetyl derivative of fluticasone (FLU) is highly potent but much safer than the currently used propionate or furoate ester.

Evaluating the cytotoxic effects of novel quinone compounds

BACKGROUND/AIM

Quinone-containing compounds can induce cell death in cancer cells and are, therefore, promising lead compounds for the development of novel anti-cancer drugs.

MATERIALS AND METHODS

In the present study, we evaluated the cytotoxic effects of fifteen novel synthetic quinone-containing compounds in cell cultures in an attempt to establish structure/activity relationships for these compounds. The compounds were clustered into four groups (1, 2, 3, 4) based on common structural features. In vitro cell cultures were treated for 24 h with the compounds, after which cell viability was assessed by flow cytometry. The APOPercentage™ assay, the Terminal deoxynucleotidyl transferase mediated dUTP Nick End Labeling (TUNEL) assay and the caspase-3 assay was used to investigate the activation of apoptosis in the cells.

RESULTS

Compounds from groups 2 and 4 were highly toxic to the cells. The compounds induced apoptosis in some human cancer cell cultures and exhibited low toxicity towards the non-cancerous cell line, KMST-6. The induction of apoptosis in CHO cells was associated with the activation of caspase-3 cleavage, DNA fragmentation and the reactive oxygen species (ROS) generation.

CONCLUSION

The present study demonstrates that five of the quinone-containing compounds induced apoptosis in human cancer cells and are therefore promising lead compounds for the development of novel anticancer drugs.