1-1-diphenyl-2-picrylhydrazyl and alpha-terpineol

Citrus aurantium leaves' essential oils (EOs) were evaluated for chemical composition and antioxidant and antibacterial activities. The vegetable material, taken 5 times during the year, has undergone the hydrodistillation to prepare EO. Chemical characterization by gas chromatography/mass spectrometry and GC/flame ionization detection allowed the identification of 46 compounds, and a notable quantitative and qualitative differences between the different Petitgrain samples according to the harvest time. Linalool (43.2% to 65.97%), linalyl acetate (0.77% to 24.77%), and α-terpineol (9.29% to 12.12%) were the main components. The most important number of components was registered for summer EOs (July and September). The 5 EOs submitted biological activities screening, namely, antioxidant and antimicrobial activities. Weak antioxidant activities (IC(50) values >10000 mg/L) were registered by both 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azinobis-3-ethylbenzothiazoline-6-sulphonate assays, mostly because the weak amount of phenols in EOs. Antibacterial activities (12 microorganisms) were registered against Gram-positive bacteria [Bacillus subtilis (MIC = 2.7 mg/mL), Staphylococcus aureus (4.8 mg/mL)], and moderated ones against yeasts [Saccharomyces cerevisiae (9.2 mg/mL)] and fungi [Mucor ramannianus (5 mg/mL)]. Positive correlations between the identified compounds and the antimicrobial activities were noted. Many compounds were correlated to antimicrobial activity mainly caryophyllene oxide against Escherichia coli (R(2) = 0.99), S. cerevisiae (R(2) = 0.99), and Fusarium culmorum (R(2) = 0.99).

Topics: Acyclic Monoterpenes; Anti-Infective Agents; Antioxidants; Bacillus subtilis; Biphenyl Compounds; Citrus; Cyclohexane Monoterpenes; Cyclohexenes; Escherichia coli; Flame Ionization; Food Contamination; Food Microbiology; Fusarium; Gas Chromatography-Mass Spectrometry; Microbial Sensitivity Tests; Monoterpenes; Mucor; Oils, Volatile; Picrates; Plant Leaves; Polycyclic Sesquiterpenes; Saccharomyces cerevisiae; Seasons; Sesquiterpenes; Staphylococcus aureus

α-Terpineol is a relatively cheap and abundant aroma compound. It is widely used in food, cosmetics, and household products. Many of its monoterpene counterparts have been applied in antiproliferative assays, leading to promising results in the prevention or even treatment of cancers. However, despite its theoretic potential, no paper reports the evaluation of antiproliferative capacity of this alcohol. Thus, antioxidant potential of three monoterpenoids (carvone, perillyl alcohol, and α-terpineol) was measured using two methods: DPPH and ORAC. Also, the antiproliferative effect of these monoterpenoids against nine cancerous cell lines were performed and compared to limonene and doxorubicin. Results showed that all samples tested had very low antioxidant activity in the DPPH assay, but α-terpineol (2.72μmolTrolox equiv./μmol) could be compared to commercial antioxidants in the ORAC assay. The antiproliferative results obtained encourage future in vivo studies for α-terpineol, since this monoterpenoid presented cytostatic effect against six cell lines, especially for breast adenocarcinoma and chronic myeloid leukemia, in a range of 181-588μM.

Topics: Antioxidants; Biphenyl Compounds; Cell Proliferation; Cyclohexane Monoterpenes; Cyclohexenes; HT29 Cells; Humans; K562 Cells; Monoterpenes; Picrates