Gas chromatography-mass spectrometry (GC-MS) analysis revealed the major components in black cumin essential oils which were thymoquinone (37.6%) followed by p-cymene (31.2%), α-thujene (5.6%), thymohydroquinone (3.4%), and longifolene (2.0%), whereas the oleoresins extracted in different solvents contain linoleic acid as a major component. The antioxidant activity of essential oil and oleoresins was evaluated against linseed oil system at 200 ppm concentration by peroxide value, thiobarbituric acid value, ferric thiocyanate, ferrous ion chelating activity, and 1,1-diphenyl-2-picrylhydrazyl radical scavenging methods. The essential oil and ethyl acetate oleoresin were found to be better than synthetic antioxidants. The total phenol contents (gallic acid equivalents, mg GAE per g) in black cumin essential oil, ethyl acetate, ethanol, and n-hexane oleoresins were calculated as 11.47 ± 0.05, 10.88 ± 0.9, 9.68 ± 0.06, and 8.33 ± 0.01, respectively, by Folin-Ciocalteau method. The essential oil showed up to 90% zone inhibition against Fusarium moniliforme in inverted petri plate method. Using agar well diffusion method for evaluating antibacterial activity, the essential oil was found to be highly effective against Gram-positive bacteria.

The essential oils of seven aromatic plants from Córdoba, San Luis and San Juan Provinces (Argentina) were isolated by steam distillation and analysed by a gas chromatography/mass spectrometry technique. The oils were screened for cytotoxicity and in vitro inhibitory activity against herpes simplex virus type 1 (HSV-1), dengue virus type 2 (DENV-2) and Junin virus (JUNV) by a virucidal test. The oils showed a variable virucidal action according to the virus. The better relationship between cytotoxicity and antivirus action was observed with the essential oils of Heterothalamus alienus and Buddleja cordobensis against JUNV, with virucidal concentration 50% (VC50) values of 44.2 and 39.0 ppm and therapeutic indices (cytotoxicity to virucidal activity ratio) of 3.3 and 4.0, respectively. The inhibitory action was exerted by a direct interaction of virions with the oils. Virions inactivated with B. cordobensis and H. alienus essential oil were not affected in their ability to bind to the host cell. The therapeutic indices shown by these essential oils in toto were very modest, but given the complexity of their chemical composition the future identification of the precise active principle may allow the elimination of cytotoxic components and increase the selectivity of the effective compound.

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