Extraction, Chemical Composition, and Anticancer Potential of Origanum onites L. Essential Oil.

Origanum species are plants rich in volatile oils that are mainly used for culinary purposes. In recent years, there has been a growing interest in the biological activities of their essential oils. Origanum onites L. is a plant mainly found in Greece, Turkey, and Sicily, whose oil is rich in carvacrol, a highly bioactive phytochemical. The aim of this study was to analyze the chemical composition of Origanum onites essential oil (OOEO), and investigate its potential anticancer effects in vitro and in vivo. GC/MS analysis identified carvacrol as OOEO's main constituent. In vitro antiproliferative activity was assayed with the sulforhodamine B (SRB) assay against human cancer cell lines from four tumor types. HT-29, a colorectal cancer cell line, was the most sensitive to the antiproliferative activity of OOEO. Wound-healing assay and Annexin V-PI staining were employed to investigate the antimigratory and the pro-apoptotic potential of OOEO, respectively, against human (HT-29) and murine (CT26) colon cancer cells. Notably, OOEO attenuated migration and induced apoptosis-related morphological changes in both cell lines. Prophylactic oral administration of the oil in a BALB/c experimental mouse model inhibited the growth of syngeneic CT26 colon tumors. As far as we know, this is the first report on the antitumor potential of orally administered OOEO.

Composition, antimicrobial, antioxidant, and antiproliferative activity of Origanum dictamnus (dittany) essential oil.

BACKGROUND: Nowadays, there has been an increased interest in essential oils from various plant origins as potential antimicrobial, antioxidant, and antiproliferative agents. This trend can be mainly attributed to the rising number and severity of food poisoning outbreaks worldwide along with the recent negative consumer perception against artificial food additives and the demand for novel functional foods with possible health benefits. Origanum dictamnus (dittany) is an aromatic, tender perennial plant that only grows wild on the mountainsides and gorges of the island of Crete in Greece. OBJECTIVE: The aim of the present study was to investigate the antimicrobial, antioxidant, and antiproliferative properties of O. dictamnus essential oil and its main components and assess its commercial potential in the food industry. DESIGN: O. dictamnus essential oil was initially analyzed by gas chromatography-mass spectrometry (GC-MS) to determine semi-quantitative chemical composition of the essential oils. Subsequently, the antimicrobial properties were assayed and the minimum inhibitory and non-inhibitory concentration values were determined. The antioxidant activity and cytotoxic action against the hepatoma adenocarcinoma cell line HepG2 of the essential oil and its main components were further evaluated by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and by the sulforhodamine B (SRB) assay, respectively. RESULTS: The main constituents of O. dictamnus essential oil identified by GC-MS analysis were carvacrol (52.2%), γ-terpinene (8.4%), p-cymene (6.1%), linalool (1.4%), and caryophyllene (1.3%). O. dictamnus essential oil and its main components were effective against Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Listeria monocytogenes, Salmonella Enteritidis, Salmonella typhimurium, Saccharomyces cerevisiae, and Aspergillus niger. In addition, the estimated IC50 value for the DPPH radical scavenging activity for O. dictamnus essential oil was 0.045±0.0042% (v/v) and was mainly attributed to carvacrol. The EC50 value for the essential oil in the 72h SRB assay in HepG2 cells was estimated to be 0.0069±0.00014% (v/v). Among the individual constituents tested, carvacrol was the most bioactive compound and accounted for the observed antiproliferative activity of the essential oil. CONCLUSIONS: The results revealed that O. dictamnus essential oil is a noteworthy growth inhibitor against the microbes studied. It also possesses significant antioxidant activity and demonstrated excellent cytotoxicity against HepG2 cells. Taken together, O. dictamnus essential oil may represent an effective and inexpensive source of potent natural antimicrobial agents with health-promoting properties, which may be incorporated in food systems.

Synthesis of new optically active 2-pyrrolidinones.

A new class of optically active 2-pyrrolidinones was synthesized, starting from S-pyroglutamic acid, a well known natural chiral synthon. The synthetic design followed led to the insertion of various substituents at positions 1 and 5 of the 2-pyrrolidinone ring, including the imidazole moiety. Some of them possess two or three stereogenic centers, the configuration of which was retained under the mild conditions used. The new compounds also carry an imidazole moiety, which, along with the 2-pyrrolidinone template, may prove pivotal to several biological processes.

Synthesis, in silico docking experiments of new 2-pyrrolidinone derivatives and study of their anti-inflammatory activity.

A new class of 2-pyrrolidinone derivatives was designed, synthesized, and tested for their antioxidant and anti-inflammatory activities. The compounds were evaluated for their inhibitory activity against LOX. The most potent among them, 14d [IC(50) 0.08 (±0.005)mM], and 14e [IC(50) 0.0705 (±0.003)mM], were also tested in vivo. The compound 14d induced equipotent inhibition against rat paw edema, which is very close to the effect produced by the commonly used standard, namely indomethacin (47%). The LOX inhibitory activity of the compound 14e proceeds in parallel to the % inhibitory value of lipid peroxidation meaning that this LOX inhibitory activity is supported by the lipid peroxidation inhibition. The molecular features that govern their bioactivity were explored through in silico docking experiments. The results showed that acidic moieties must be placed in certain distance and orientation in the active site of LOX enzyme in order to productively exhibit inhibitory activity. In addition, the 2-pyrrolidinone template significantly contributes in the inhibitory properties of the new compounds.