Effect of thyme essential oil and its two components on toxicity and some physiological parameters in mulberry pyralid Glyphodes pyloalis Walker.

Extensive usage of synthetic pesticides has proved to be destructive to all living being and the resurgence of pest resistance. Compounds derived from certain plants are usually safer compared to chemical control of pest. The present study thus intended to use Thymus vulgaris essential oil (EO) and two of its derivatives including thymol and carvacrol in order to see their deleterious effects on Glyphodes pyloalis (Walker). We also studied the oil components. This pest has recently become a serious concern for the silk industry. Our results showed that the thyme EO contain several components including thymol (26.9%), ρ-Cymene (14.54%), linalool (13.39%) and carvacrol (5.7%). Our toxicity tests revealed an estimated LD50 values for thyme EO, thymol and carvacrol 2.82, 32.18 and 56.54 µg/larva, respectively. However, the thyme EO was more toxic than its two tested compounds. The activity of certain detoxifying enzymes such as α- and ß-esterase, glutathione S-transferase and cytochrome P450 were significantly inhibited by thymol-treated larvae compared to the control group. Similarly, the activity of alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase and alkaline phosphatases enzymes in thymol-treated larvae decreased while the activity of acid phosphatases increased. Our results suggest that thyme EO and its components have potential for the control of G. pyloalis larvae in mulberry orchards, where no synthetic chemicals are allowed.

Selective immediate detection of Cu2+ by a pH-sensitive rhodamine-based fluorescence probe in breast cancer cell-line.

A biocompatible fluorogenic chemosensor (N-(3-carboxy acryloyl)) rhodamine B (RHA) comprising a furan-2,5-dione receptor and a rhodamine fluorophore via an iminohydrazine crosslinker has been prepared for more scrutinizing optical properties and utilization in molecular imaging of living cells. The consequences indicated that RHA not only is a good pH indicator in acidic media but also can be used as a great sensitive fluoroionophore with high selectivity. The fluorescence emission of the molecule RHA is quite stable in the presence of 15 diverse cations, 18 anions (especially H2PO4-, S2, and F-), and 5 amino acids with the different functional group as a model, except Cu2+ ions with observable emission intensity changing. The Cu2+ probe has a dual functional effect, an "on-off" mechanism in solvent media, and an "off-on" mechanism in Phosphate Buffered Saline (PBS) in acidic pH conditions. The detection limits for Cu2+ in acetone-water media was 0.69 µM and 0.18 µM in pH = 5.0. Moreover, RHA can fluorescently and colorimetrically image Cu2+ ions in acidic and neutral pH with low cytotoxicity in living cells.