Exploring the Anticancer Potential of Origanum majorana Essential Oil Monoterpenes Alone and in Combination against Non-Small Cell Lung Cancer

Lung cancer is the second most commonly diagnosed cancer and has the highest mortality rate worldwide despite the remarkable advances in its treatment. Origanum majorana Essential Oil (OMEO) has been shown to be effective against non-small cell lung cancer (NSCLC) cells, decreasing their viability and colony growth in vitro, as well as inhibiting tumor growth in chick embryo chorioallantoic membranes (CAM) and nude mice in vivo. OMEO is mainly composed of four monoterpenes, namely terpinen-4-ol, sabinene hydrate, α-terpinene, and γ-terpinene. In this study, we aimed to investigate the potential anticancer effects of these monoterpenes, either alone or in combination, on NSCLC. Our findings indicate that these four monoterpenes significantly decreased NSCLC cell viability in a concentration-dependent manner, reduced their colony growth in vitro, and also downregulated survivin expression in these cells. Moreover, different combined mixtures of these monoterpenes further enhanced their anticancer effects on cellular viability, with a terpinen-4-ol and sabinene hydrate combination being the most potent. We also found that terpinen-4-ol, in combination with sabinene hydrate, markedly enhanced the anticancer effect of the individual monoterpenes on NSCLC viability within a shorter treatment duration through, at least in part, survivin downregulation. Furthermore, this combination enhanced the inhibition of colony growth in vitro and the tumor growth of NSCLC cells xenografted onto chick embryo CAM in vivo. Altogether, our study highlights the potential of these monoterpenes for use in further pre-clinical investigations against various cancer hallmarks.

Utilization of Nutmeg (Myristica fragrans Houtt.) Seed Hydrodistillation Time to Produce Essential Oil Fractions with Varied Compositions and Pharmacological Effects

The intent of this study was to utilize distillation timeframes (DT) of nutmeg (Myristica fragrans) essential oil (EO) to generate fractions with differential chemical compositions and bioactivity. Ten fractions were captured at the following distillation timeframes: 0.0–0.5, 0.5–1.0, 1.0–2.5, 2.5–5.0, 5.0–10, 10–30, 30–60, 60–90, 90–120, and 120–240 min. In addition, a control EO was collected from a straight 0–240 min non-stop distillation. ANOVA and advanced regression modeling revealed that the produced EO fractions possess substantial variation in the concentration of potentially desired compounds. The concentrations (%) of α-phellandrene, 3-carene, p-cymene, limonene, α-thujene, α-pinene, camphene, sabinene, β-pinene, and myrcene decreased, while the concentrations (%) of α-terpinene, γ-terpinene, terpinolene, and myristicin increased in later DT fractions. Nutmeg EO showed some antimalarial activity against Plasmodium falciparum D6, but did not exhibit significant antifungal activity. In general, nutmeg seed oil yields increased with an increase of DT. These results may be utilized by industries using nutmeg EO.

Kinetic study on the singlet oxygen quenching activity of nordihydroguaiaretic acid (NDGA) using methylene blue sensitized photooxidation of α-terpinene

Singlet oxygen is highly reactive and can therefore induce rapid oxidation of a range of biological molecules, causing cell damages. The effects of nordihydroguaiaretic acid (NDGA) on the photochemical singlet oxygen oxidation of α-terpinene in methanol were studied. NDGA showed strong protective activity on the singlet oxygen oxidation of α-terpinene in methanol in a dose dependent manner. The protective activity of NDGA was considerably higher than that of butylated hydroxytoluene and 1,4-diazabicyclo[2.2.2]octane. Total singlet oxygen quenching rate constant (k r +k q ) of NDGA was determined by a steady state kinetic equation. The total singlet oxygen quenching rate constant of NDGA was 9.81×107 M-1 sec-1. The result showed that NDGA possessed strong singlet oxygen quenching activity, indicating its potential for the protection of molecules, cells and nutrients from the highly reactive singlet oxygen. To the best of our knowledge, this is the first report on the singlet oxygen quenching rate constant of NDGA.

by GC-MS

A sensitive and reliable GC-MS method was developed and validated for the simultaneous determination of ascaridole, p-cymene and α-terpinene in rat plasma using naphthalene as internal standard. The plasma samples were extracted with ethyl acetate. Chromatographic separation was carried out on a HP-5MS capillary analytical column (30 m × 0.25 mm, 0.25 µm) and detection was performed on a quadrupole mass spectrometer detector operated under selected ion monitoring mode. The method showed excellent linearity over the investigated concentration range (r > 0.99) with the limit of quantitation down to 50, 10 and 5 ng/mL for ascaridole, p-cymene and α-terpinene, respectively. The intra-day and inter-day precisions (RSD) were <11.3%, and the accuracy was between 90.7 and 113.8%. The method was successfully applied to investigate the pharmacokinetics of Chenopodium ambrosioides L. following oral administration to rats.