Integrative effects of phytohormones in the phenolic acids production in Salvia verticillata L. under multi-walled carbon nanotubes and methyl jasmonate elicitation.

Salvia verticillata L. is a well-known herb rich in rosmarinic acid (RA) and with therapeutic values. To better understand the possible roles of phytohormones in the production of phenolic acids in S. verticillata, in this work, we investigated some physiological and biochemical responses of the species to methyl jasmonate (MJ) and multi-walled carbon nanotubes (MWCNTs) as two effective elicitors. The leaves were sprayed with aqueous solutions containing 100 mg L-1 MWCNTs and 100 µM MJ and then harvested during interval times of exposure up to 96 h. The level of abscisic acid, as the first effective phytohormone, was altered in the leaves in response to MJ and MWCNTs elicitation (2.26- and 3.06-fold more than the control, respectively), followed by significant increases (P ˂ 0.05) detected in jasmonic acid and salicylic acid contents up to 8 h after exposure. Obtained data revealed that simultaneously with changes in phytohormone profiles, significant (P ˂ 0.05) rises were observed in the content of H2O2 (8.85- and 9.74-folds of control), and the amount of lipid peroxidation (10.18- and 17.01-folds of control) during the initial times after exposure to MJ and MWCNTs, respectively. Later, the content of phenolic acids increased in the elicited leaves due to changes in the transcription levels of key enzymes involved in their biosynthesis pathways, so 2.71- and 11.52-fold enhances observed in the RA content of the leaves after exposure to MJ and MWCNTs, respectively. It is reasonable to conclude that putative linkages between changes in some phytohormone pools lead to the accumulation of phenolic acids in the leaves of S. verticillata under elicitation. Overall, the current findings help us improve our understanding of the signal transduction pathways of the applied stimuli that led to enhanced secondary metabolite production in medicinal plants.

Fatty Acid Patterns of Seeds of Some Salvia Species from Iran--A Chemotaxonomic Approach.

In this study, the seed oil content and fatty acid (FA) profile of 21 populations from 16 wild Salvia species of Iran were analyzed by GC. Patterns of chemical variations of the oils among species were identified via numerical analyses and also the taxonomic status of the infrageneric grouping was outlined in the genus. Salvia species were scored based on the contents of main FAs using principal coordinate analysis (PCO). The results showed that the total oil content in the seeds varied significantly, and ranged from 6.68 to 38.53% dry weight. α-Linolenic (18:3ω3, 1.69 - 53.56%), linoleic (18:2ω6, 13.04 - 60.64%), oleic (18:1ω9, 6.15 - 27.06%), palmitic (16:0, 3.77 - 9.27%), and stearic (18:0, 1.78 - 3.05%) acid were identified as five major FAs in the oils. The amount of ω-3 and ω-6 FAs ranged between 1.90 - 53.80% and 13.46 - 60.83% of total FAs in the seed oils, respectively. The results confirmed that FA profiles were distinctive among the species and that they can be used as chemotaxonomic markers. The discrimination of Salvia species according to their botanical classification at intersectional level was supported. In general, seed oils of Salvia species were rich sources of polyunsaturated FAs, except in linoleic and α-linolenic acid, and may be valuable for food and pharmaceutical industries.

--Essential-oil composition of the fruits of six Heracleum L. species from Iran: chemotaxonomic significance.

The fruit essential oils of Heracleum persicum, H. rechingeri, H. gorganicum, H. rawianum, H. pastinacifolium, and H. anisactis from Iran were obtained by hydrodistillation and characterized by GC-FID and GC/MS analyses. The oils of the six species were compared to determine the similarities and differences among their compositions. Overall, 36 compounds were identified in the fruit oils, accounting for 92.40-96.74% of the total oil compositions. Aliphatic esters constituted the main fraction of the oils (86.61-94.31%), with octyl acetate and hexyl butyrate as the major components. The oil compositions of species belonging to section Pubescentia (H. persicum, H. gorganicum, and H. rechingeri) were discriminated by equally high contents of both octyl acetate (13.84-20.48%) and hexyl butyrate (17.73-38.36%). On the other hand, the oils of H. rawianum, H. pastinacifolium and H. anisactis, belonging to section Wendia, showed lower hexyl butyrate contents (3.62-6.6%) and higher octyl acetate contents (48.71-75.36%) than the former. Moreover, isoelemicin was identified at low amounts (0.10-2.51%) only in the oils of the latter species. The differences in the oil composition among the six species were investigated by hierarchical cluster and principal component analyses, which indicated that the oil composition confirmed well the taxonomical classification based on the morphological and botanical data, and, thus, may provide a reliable marker to discriminate Heracleum species at the intersectional level.

Impacts of foliar exposure to multi-walled carbon nanotubes on physiological and molecular traits of Salvia verticillata L., as a medicinal plant.

Owing to the growing applications of the multi-walled carbon nanotubes (MWCNTs) in the communications and energy industries, they have attracted increasing attention for their effects on the environment and plants. Therefore, we investigated the impact of foliar exposure to MWCNTs on the oxidative stress responses in the Salvia verticillata as a medicinal plant. Furthermore, we evaluated the possible correlations between gene expression and activity of the key enzymes in the phenolic acids biosynthesis pathways and their accumulation in the treated leaves. The leaves of two-month-old plants were sprayed with different concentrations (0-1000 mg L-1) of MWCNTs. Raman's data and Transmission Electron Microscopy images have confirmed the absorption of MWCNTs via epidermal cells layer into the parenchymal cells of the exposed leaves. The results showed that exposure to MWCNTs led to a decrease in the photosynthetic pigments and increases in the oxidative stress indices (enzymatic and non-enzymatic antioxidants) in the leaves with a dose-dependent manner. The content of rosmarinic acid as a main phenolic acid was increased in the MWCNTs-exposed leaves to 50 and 1000 mg L-1, nearly four times relative to the control. Unlike with other examined enzymes, a positive correlation was deduced between the activity and gene expression patterns of the rosmarinic acid synthase with the rosmarinic acid accumulation in the treatments. Overall, MWCNTs at the low concentrations could promote the production of the pharmaceutical metabolites by the changes in the ROS generation. However, at the higher concentrations, MWCNTs were toxic and induced the oxidative damages in S. verticillata.