Influence of Extraction Duration on the Chemical Composition and Biological Activities of Essential Oil of Thymus pallescens de Noé

Abstract

Thymus pallescens de Noé essential oils were isolated from the plant's dried leaves, by hydrodistillation, with different distillation times (30 min, 1, 2 and 3 h). The essential oils compositions and their antioxidant, antimicrobial and insecticidal activities were examined. The chemical compositions of the oils were determined by GC and GC-MS. The antioxidant capacity was tested by four complementary methods: thiobarbituric acid reactive substances, ferric reducing power and scavenging of radicals DPPH • (2,2-diphenyl-1-picrylhydrazyl) and ABTS •+ [2,2 -azino-bis (3-ethylbenzthiazoline-6-sulfonic acid)]. The antimicrobial activity was tested against three bacteria, two gram-positive (Staphylococcus aureus and Bacillus subtilis) and one gram-negative (Escherichia coli) and one yeast (Candida albicans). The insecticidal activity against confused flour beetle Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae) was evaluated using direct contact application and fumigant method. The predominant components in the oils were carvacrol (63.3-68.2 %), γ -terpinene (6.9-9.1 %), p-cymene (6.2-10.3 %) and thymol (6.5-7.5 %). The antioxidant activities were dependent on the time of hydrodistillation and the method used. The essential oils extracted for 30 min and 1 h were the most efficient against all the bacteria used. Toxicity tests against T. con-B Mohamed Hazzit

Toxicity and repellent activities of Thymus pallescens and Cymbopogon citratus essential oils against Sitophylus granarius

“…The chemical compositions of the EOs were analyzed by GC-MS, which resulted in the identification and quantification of more than 30 compounds. Our analysis showed that carvacrol (67.2%), p-cymene (16.2%), and thymol (4.9%) were the major components of T. pallescens EO, which agrees with previous studies (Benchabane et al 2015;Moutassem et al 2019). The major volatile constituents of C. citratus EO were identified as geraniol (20.8%) and limonene (10.5%), which are similar to those identified in previous studies conducted on the same species, with only slight differences (Bassolé et al 2011;Moutassem et al 2019).…”

Chemical and Biological Profile and Allergenicity of Thymus baicalensis Plant of Mongolian Origin

“…Benchabane et al and Jarić et al described similar findings in Thymus -tested samples. The authors concluded that thymol and carvacrol were not present in tested Thymus species cultivated in Lithuania, Estonia and Spain [ 23 , 24 ]. In another study, myrcene was reported in Thymus serpyllum L. up to 74.2% of the total determined volatile compounds, depending on the volatile oil extraction technique [ 25 ].…”

Application of a Multisystem Coating Based on Polymeric Nanocapsules Containing Essential Oil of Thymus Vulgaris L. to Increase the Shelf Life of Table Grapes (Vitis Vinifera L.)

“…The EOt was obtained by hydrodistillation [27]. Briefly, fresh-cut plant was hydrodistilled using a Clevenger-type apparatus (100 g• L −1 water) for 4 h. The oil was collected and kept at 4 • C until use.…”

“…Absorbances of these solutions were measured at 517 nm (Epoch Microplate Spectrophotometer, Biotek, USA). On the other hand, the ABTS + method [27] is based on the reduction of the green ABTS + radical cation. A volume of 25 μL of each solution (NC-EOt, EOt or carvacrol, at a concentration of 1000 μg• mL −1 ) was added to 1 mL of ABTS + methanol solution (7 mM).…”