Volatile Composition and Biological Activities of the Leaf Essential Oil from Zanthoxylum limoncello Grown in Oaxaca, México.

Zanthoxylum limoncello is a native plant from southern Mexico which is used as a timber source, condiment and as a traditional medicine. Herein, we report on the volatile content of the leaf essential oil and its biological activities. The annual essential oils (2015-2018) contained volatile organic compounds which exhibited a moderate growth inhibitory activity against H. pylori ATCC 53504 (MIC 121.4-139.7 µg mL-1 ), 26695 (MIC 85.5-94.9 µg mL-1 ) and J99 (MIC 94.7-110.4 µg mL-1 ). These hydrodistillates contained 2-undecanone (31.6-36.8 %; MIC 185.3-199.2 µg mL-1 ) and 2-undecenal (25.1-35.7 %; MIC 144.8-111.3 µg mL-1 ) as the most abundant compounds which were partially involved in the anti-H. pylori activity. The human ornithine decarboxylase enzyme (ODC1), which shows increased activity in several cancer types, was non-competitively inhibited (Vmax 2.7>0.8 Kcat s-1 ) by the essential oil of Z. limoncello as well as by 2-undecanone and 2-undecenal in accordance to in vitro kinetic studies. In silico calculations strongly suggest that the carbonyl group of these oxygenated hydrocarbons interacts with both Asn319 and Ala39 at the subunit A of ODC1. Considering that Ala39 is located close to Asn44, a crucial amino acid of the ODC's allosteric site, the non-competitive inhibition of the enzyme by 2-undecanone and 2-undecenal is endorsed. Finally, the essential oil of Z. limoncello and its main volatiles showed a significant (p<0.01) and prolonged repellent effect against Aedes aegypti.

Volatile Profiling, Insecticidal, Antibacterial and Antiproliferative Properties of the Essential Oils of Bursera glabrifolia Leaves.

The present article describes the chemical composition and biological activities of the essential oils of B. glabrifolia leaves obtained in four consecutive years (2015-2018). The essential oils contained α-terpineol (17.9-29.7 %), α-terpinene (12.6-17.4 %), limonene (14.9-26.8 %) and ß-pinene (2.1-16.7 %) as the most abundant volatiles. The essential oils and these volatiles showed a significant adulticide activity (p<0.01; LC50 <100 µg mL-1 ) on the maize weevil (Sitophilus zeamais) with a 100 % mortality rate within a period of 5 h. Also, the essential oils showed a strong antibacterial activity on Enterococcus faecalis ATCC 29212 (MIC, 132.7-173.6 µg mL-1 ) and Helicobacter pylori ATCC 43504 (MIC, 74.8-199.2 µg mL-1 ). The assessment of the main volatiles revealed α-terpineol as the principal antibacterial agent (MIC, 78.6-149.7 µg mL-1 ). Similarly, the essential oils exhibited a substantial in vitro antiproliferative activity on the human prostate cancer cell lines PC-3 (LC50 , 15.2-19.4 µg mL-1 ), the human ovarian carcinoma cell lines OVCAR-3 (LC50 , 27.3-53.7 µg mL-1 ) and the myelogenous leukemia cell lines K-562 (LC50 , 32.4-75.9 µg mL-1 ). α-Terpineol (LC50 , 32.4-75.9 µg mL-1 ) exhibited the strongest antiproliferative effect on these cancer cell lines (LC50 , 22.4-48.1 µg mL-1 ).

Chemical profile and pharmacological effects of the resin and essential oil from Bursera slechtendalii: A medicinal "copal tree" of southern Mexico.

This study reports on the volatile profile and pharmacological activities of the essential oil and resin from Bursera slechtendalii, an aromatic medicinal tree commercialized in southern Mexico. The essential oil contained 25 volatiles including p-cymen-8-ol (25.4-35.7%), n-hexyl hexanoate (6.8-17.6%) and n-octyl hexanoate (7.6-14.8%), whereas the crystallized resin contained 14 volatiles, including n-octyl acetate (29.6-34.2%), limonene (15.8-18.7%) and n-octyl butyrate (12.6-17-6%). The inhalation of vapors from the resin and essential oil caused a significant anxiolytic-like effect (p < .01) in ICR mice after 20 min of exposure at a dose of 50-150 mg L-1. The prolonged inhalation of the essential oil (for 40 days, for 15 min, twice a day) produced a significant decrease (p < .01) in total cholesterol and LDL-c content as well as an increase of HDL-c levels in the same murine model. Interestingly, levels of hepatic lipid hydroperoxide decreased, whereas the hepatic activity of superoxide dismutase and glutathione peroxidase was significantly enhanced (P < .05). The detection of p-cymen-8-ol and n-octyl acetate in the plasma of mice strongly suggests their bioavailability and possible role in the biological activities described herein. Also, both the resin and essential oil from B. slechtendalii, as well as their main volatiles, showed a potent repellence activity against Aedes aegypti (p < .01).