Volatile compositions and glandular trichomes of Zataria multiflora in different phenological stages under normal and drought stress conditions

BACKGROUND

Zataria multiflora Boiss. is a medicinal and aromatic plant from the Lamiaceae family. It is extensively used in Iranian traditional medicine, mostly as a replacement for Thyme species. This study was focused on the analysis of chemical composition and the distribution and types of trichomes of Z. multiflora grown under different conditions. Equilibrium headspace analysis in combination with GC-FID-MS was used to identify volatile compounds released by aerial parts of Z. multiflora in development stages of 50 and 100% flowering under normal and drought-stress conditions.

RESULTS

The main constituents were p-cymene (20.06-27.40%), γ-terpinene (12.44-16.93%), and α-pinene (6.91-16.58%) and thymol (8.52-9.99%). The highest content of p-cymene (27.40%) and thymol (9.99%) was observed in the 50% flowering stage at the 90% field capacity, while the maximum γ-terpinene (16.93%) content was recorded in the 100% flowering stage under normal conditions. Using the SEM method, it was found that peltate glandular and non-glandular trichomes are distributed on the surface of the leaf, stem, and outer side of the calyx. However, capitate trichomes only are detected on the stem and calyx in the 100% flowering and beginning of blooming stages, respectively. The type and structure of trichomes do not vary in different development stages, but they differ in density. The highest number of leaf peltate glandular trichomes was observed in the vegetative and beginning of blooming stages at 50% and 90% field capacity, respectively. Non-glandular trichomes of the stem were observed with high density in both normal and stress conditions, which are more densely in 90% field capacity.

CONCLUSIONS

Since this plant has strong potential to be used in the food and pharmacological industries, this study provides valuable information for its cultivation and harvesting at specific phenological stages, depending on desired compounds and their concentrations.

Headspace-Low Water Absorption Trap Technique: Analysis of Low-Abundance Volatile Compounds from Fresh Artemisia Annua L. with GC-MS

Conventional headspace (HS) method could not meet the requirement of analyzing low-abundance volatile compounds in high water content samples. A HS-low water absorption trap technique coupled with gas chromatography-mass spectrometry was introduced to remove the large amount of water vapor; therefore, the low-abundance volatile compounds could be detected with better analytical sensitivity. With this method, a total of 81 volatile compounds were identified from fresh Artemisia annua L. by mass spectral library search, retention index and accurate mass measurement, which could make the qualitative results more accurate and reliable. These compounds belonged to different species, including terpene, cycloparaffin, aliphatic aldehyde, aromatic ketone, aromatic aldehyde and so on. The 2,5,6-trimethyl-1,3,6-heptatriene (8.23%) was the most principal compound, followed by γ-muurolene (6.80%), β-caryophyllenea (6.24%), 1,8-cineol (5.76%), 2-carene (5.65%), borneol (5.57%), isocaryophyllene (4.91%), bornylene (4.78%), camphene (4.30%) and β-pinene (4.26%) as the main components. The results indicated that this method presents a great potential for the trace analysis of volatile compounds in complex high water content samples.

Chemical composition and antinociceptive activity of volatile fractions of the aerial parts of Solidago chilensis (Compositae)

Abstract Thirty-six compounds were identified from aerial parts of Solidago chilensis cultivated at PAF/FIOCRUZ campus in Rio de Janeiro city (RJ) using solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) analysis. These compounds are mainly non-oxygenated mono and sesquiterpenes. Germacrene D is the major compound of two the essential oil analyzed samples (12 to 23%) and of two of the volatiles samples analyzed by SPME (central stems and dry inflorescences samples). Limonene is the major compound in the fresh inflorescences sample (about 21%). The bornil acetate is present in both volatile fractions (16%) and essential oils (7-8%). All the essential oils samples evaluated shown a great antinociceptive activity, considering the used dose of the samples (1 mg/kg) and the standard substance (50 mg/kg). Solidago chilensis is one of Brazil arnicas and it is a medicinal plant widely used by the brazilian population. Other plants of the genus Solidago are also used in traditional medicine in North America and Europe. This is the first report of SPME analysis from Solidago genus and of the antinociceptive effect from Solidago chilensis essential oil.

Microwave-Assisted Isolation of Essential Oils from Nepeta Crispa and N. Racemosa and Comparisons with the Conventional Method

In this study microwave-assisted hydrodistillation (MAHD) has been compared with the conventional method of hydrodistillation for the extraction of the essential oils from two Iranian Lamiaceae species: Nepeta crispa Willd and N. racemosa Lam. The essential oils extracted by MAHD for 40 min were quantitatively and qualitatively (aromatic profile) similar to those obtained by conventional hydrodistillation for 3.5 h. The MAHD method yields an essential oil with higher amounts of more valuable oxygenated compounds, and allows substantial savings of costs in terms of time, energy and plant material.