Effect of Harvest Time on Yield, Chemical Composition, Antimicrobial and Antioxidant Activities of Thymus vulgaris and Mentha pulegium Essential Oils

Abstract

Aims: This work aims to study the effect of the harvest time (pre-flowering and full-flowering) on the yield, chemical composition, antimicrobial and antioxidant activities of Thymus vulgaris and Mentha pulegium essential oils (EOs). Study Design: Leaves and flowers from each period (pre and full-flowering) were used for EOs extraction. EO yield, chemical composition, antimicrobial and antioxidant activities were determined for each plant at the two harvest times studied. Place and Duration of Study: The studied plants (T. vulgaris and M. pulegium) were collected during the period of April 2011 (Pre-flowering) to June 2011 (Full-flowering). Experiments were conducted at the chemistry and microbiology laboratory of the National Institute of Agronomic Research of Tangier (Morocco). Methodology: The EOs were extracted via steam distillation. Chemical composition has been determined by a GC/MS analysis. Antimicrobial activity against Escherichia coli (SCTC 471), Salmonella Senftenberg 775W (ATCC 43845), Listeria monocytogenes (SCTC 4031) and Staphylococcus aureus (SCTC 976) was determined by paper disc agar plates. Antioxidant activity were determined by the radical scavenging activity assay. Results:The greatest yield for T. vulgaris (3.6%) and for M. pulegium (3.5%) EOs was obtained during the full-flowering period. The chromatographic analysis showed that the studied EOs were constituted mainly by carvacrol for T. vulgaris and pulegone for M. pulegium. Harvest time affected quantitatively but not qualitatively the chemical composition of both EOs. T. vulgaris EO showed a greater antimicrobial and antioxidant activity than that of M. pulegium. The antimicrobial and antioxidant activities were maximal during the full-flowering period for T. vulgaris EO whereas they were greater in the pre-flowering period for M. pulegium EO. Conclusion:The full-flowering period would be the best time to harvest T. vulgaris plants to obtain EOs with better yield, antimicrobial and antioxidant activity. In contrast, the pre-flowering stage would allow producers to obtain a M. pulegium EO with higher antimicrobial and antioxidant activities although with a lower yield.

Citrus Peel Oils Supplementation in Broiler Diet: Effects on Performance, Jejunum Microflora and Jejunum Morphology

“…Citrus essential oils contain high amounts of limonene and linalool. It is reported that the chemical composition of these oils was strongly influenced by harvesting time (Kırbaşlar et al, 2001;Zantar et al, 2015).…”

Chemical composition and antimicrobial activity of essential oils from leaves and rhizomes of Curcuma zedoaria obtained via supercritical fluid extraction

“…For example, C. zedoaria rhizome essential oils from China and India were obtained in yields of 0.63% and 0.36%, respectively (Mau et al, 2003;Purkayastha et al, 2006), while C. zedoaria leaf essential oils from India and Bangladesh were obtained in yields of 0.2% and 0.8%, respectively (Garg et al, 2005;Rahman et al, 2014). These differing essential oil yields may be attributable to varying geographical origins, climatic conditions, environmental conditions, and extraction methods (Zantar et al, 2015;Thinh et al, 2022).…”

VARIATION IN WINTER SAVORY (Satureja montana L.) YIELD AND ESSENTIAL OIL PRODUCTION AS AFFECTED BY DIFFERENT PLANT DENSITY AND NUMBER OF HARVESTS

“…It seems that these modifications are due to the superimposition of two types of variation: agronomic and climatic. Harvest date of herbal raw materials from essential oil plants determines their chemical composition and biological activity mostly due to ontogenetic variation [Ibrahim et al 2014, Zantar et al 2015. The marjoram herb harvested at the beginning of September contains more oil than that cut in the middle of July [Zawiślak and Dzida 2010].…”