Ten essential oils, namely, mint (Mentha spicata L.,Lamiaceae), ginger (Zingiber officinaleRosc.,Zingiberaceae), lemon (Citrus limon Burm.f.,Rutaceae), grapefruit (Citrus paradisi Macf., Rutaceae), jasmine (Jasminum grandiflora L.,Oleaceae), lavender (Mill.,Lamiaceae), chamomile (Matricaria chamomilla L., Compositae), thyme (Thymus vulgaris L., Lamiaceae), rose (Rosa damascena Mill.,Rosaceae) and cinnamon (Cinnamomum zeylanicumN. Lauraceae) were tested for their antibacterial activities towards Propionibacterium acnes and in vitro toxicology against three human cancer cell lines. Thyme, cinnamon and rose essential oils exhibited the best antibacterial activities towards P. acnes, with inhibition diameters of 40 ± 1.2 mm, 33.5 ± 1.5 mm and 16.5 ± 0.7 mm, and minimal inhibitory concentrations of 0.016% (v/v), 0.016% (v/v) and 0.031% (v/v), respectively. Time-kill dynamic procedures showed that thyme, cinnamon, rose, and lavender essential oils exhibited the strongest bactericidal activities at a concentration of 0.25% (v/v), and P. acnes was completely killed after 5 min. The thyme essential oil exhibited the strongest cytotoxicity towards three human cancer cells. Its inhibition concentration 50% (IC₅₀) values on PC-3, A549 and MCF-7 tumor cell lines were 0.010% (v/v), 0.011% (v/v) and 0.030% (v/v), respectively. The cytotoxicity of 10 essential oils on human prostate carcinoma cell (PC-3) was significantly stronger than on human lung carcinoma (A549) and human breast cancer (MCF-7) cell lines.

In the present study, anti-IBV (infectious bronchitis virus) activities of (-)-pinenes were studied by MTT assay, as well as docking and molecular dynamic (MD) simulations. The CC₅₀ values of (-)-α-pinene and (-)-β-pinene were above 10 mM. And the maximum noncytotoxic concentrations (TD₀) of (-)-α-pinene and (-)-β-pinene were determined as 7.88 ± 0.06 and 6.09 ± 0.31 mM, respectively. The two compounds were found to inhibit IBV with an IC₅₀ of 0.98 ± 0.25 and 1.32 ± 0.11 mM. The MTT assay showed that the inhibitions of (-)-pinenes against IBV appear to occur moderately before entering the cell but are much stronger occur after penetration of the virus into the cell. Molecular simulations indicated that (-)-α-pinene and (-)-β-pinene specifically interact with the active site which is located at the N terminus of phosphorylated nucleocapsid (N) protein, with the former being more potent than the latter. The binding energies of them are −36.83 and −35.59 kcal mol⁻¹, respectively. Results presented here may suggest that (-)-α-pinene and (-)-β-pinene possess anti-IBV properties, and therefore are a potential source of anti-IBV ingredients for the pharmaceutical industry.

The cytotoxic activity of curcumin towards CCRF-CEM human T-cell leukemia cells was measured by the MTT assay. Tumor cells were more sensitive to the cytotoxic activity of curcumin or curcumin-Cu (II)compared to normal cells, and the IC₅₀ ofcurcumin towards CCRF-CEM cells was 8.68 µM, and that ofcurcumin-Cu (II) was 8.14 µM. The cell cycle distribution of curcumin-treated CCRF-CEM cells was analyzed by flow cytometry. DNA damage induced by oxidants such as curcumin-Cu (II) ions is considered as one of the main causes of cell inactivation. Therefore, we analyzed the effect of curcumin on DNA damage by agarose gel electrophoresis and atomic force microscopy (AFM). Gel electrophoresis analyses showed that curcumin or Cu (II) alone failed to cause DNA damage in pBR322 plasmid DNA as compared with the normal plasmid. However, DNA plasmids were mostly damaged after treatment with curcumin of different concentrations in the presence of Cu (II). Two forms were observed by means of AFM: closed circular plasmids and linear plasmids. DNA damage induced by a combination of curcumin and Cu (II) was also found by agarose gel electrophoresis, which was applied as control method to verify the results obtained by AFM.