Search

Graphical abstract Highlights • New insights regarding the mechanisms and processes involved in S. dolomitica drought adaptation are provided. • Moderate drought decreased growth, leaf water potential and stomatal conductance, while increased deyhdrin gene expression. • Severe drought decreased net photosynthesis and transpiration rate. • Drought increased sesquiterpene production by modulating gene expression of key enzymes of terpenoid biosynthesis. • Moderate drought can ameliorate secondary metabolites production and water-management practices in S. dolomitica. Abstract Sage is an important medicinal and aromatic plant. While Salvia officinalis and S. miltiorrhiza have been widely studied, little information regarding S. dolomitica exists, although it has recently attracted attention due to its anti-plasmodial and anti-inflammatory properties. This study investigated the performance and metabolic profile of this species in response to two drought treatments (moderate or severe) relative to well-watered control plants. Changes in growth and ecophysiological traits, as well as in bioactive and volatile compounds and essential oil production were determined. Given that terpenoids are the most representative class of secondary metabolites, the gene expression of key enzymes of terpenoid biosynthesis was also investigated. Moderate drought stimulated a decline in leaf water potential, growth and stomatal conductance, as well as an increase in deyhdrin expression. Serious stress symptoms occurred only in severe drought-stressed plants, where a decline in net photosynthesis and transpiration and an increase in endogenous abscisic acid was observed. Both drought stress conditions led to modulate the expression of some genes involved in biogenic volatile organic compound and essential oil biosynthesis and metabolic profile. In particular, drought induced an increase in sesquiterpene production, a class of terpenoids that is important in the food, cosmetics, and pharmaceutical industries. Thus, controlled drought, in addition to water savings during cultivation, can be applied to improve the production of secondary metabolites in S. dolomitica. [ABSTRACT FROM AUTHOR]

The volatile fractions and essential oils from Rhus coriaria fruits collected in four locations in Sicily (Italy) were characterized by GC–FID and GC–MS analysis. Monoterpenes were identified as the main class of constituents in volatiles spontaneously emitted by sumac fruits collected in two of the four sites (42.1–59.9% in ‘CNS’ and ‘CIN’ respectively), while non terpenic compounds predominated in the other two (46.1–52.8% in ‘MR’ and ‘CG’, respectively). The EO composition were characterized by high amount of non terpenic compounds (from 27.5 to 55.1%), followed by sesquiterpenes and diterpenes. p -anisaldehyde was the main constituent both in volatiles emitted by ‘CG’ sample and in its essential oil (28.4 and 20.8%, respectively). The comparison between the EOs obtained from the Sicilian samples differed from the EO obtained from sumac fruits purchased on the Jordanian market, even though a similar composition were evidenced with Turkish samples reported in the literature. [ABSTRACT FROM AUTHOR]

The genus Helichrysum Miller is a source of many bioactive metabolites commonly used in traditional medicine. In particular, Helichrysum petiolare Hilliard & B.L. Burtt shows activities as antiseptic, anti-inflammatory and in the control of anxiety disorder. Biosynthesis and accumulation of secondary metabolites is a defense mechanism of plants and it is strictly influenced by the surrounding environmental conditions. In this study, drought was imposed on H. petiolare (HEL008 clone CREA-Sanremo collection) to understand the effect of water stress on the dynamics of plant biomass and secondary metabolites production, and the morphological and physiological mechanisms involved in plant responses. H. petiolare was cultivated for 34 days under three water regimes: 100% of container capacity (CC, control), 50% CC (moderate water stress), and 0% CC (severe water stress). Plant growth traits, leaf water potential, gas exchange parameters, phenol, flavonoid, and anthocyanin content, and antioxidant activity changes were determined twice a week, while the volatile organic compounds (VOCs) and essential oils (Eos) at the end of the trial. Severe water stress dramatically reduced aerial and root dry weight, chlorophyll and carotenoid content, leaf water potential, water use efficiency (WUE, A / E ), transpiration rate ( E ), stomatal conductance ( gs ), net photosynthetic rate ( A ) and antioxidant activity. Moderate water stress induced only slight changes and led to an increase of WUE at the end of the experiment. The total amount of VOCs and Eos was not affected by water stress while their quality changed. Moderate water stress increased the main constituents of both VOCs, i.e. the monoterpene hydrocarbons, and Eos, i.e., the oxygenated sesquiterpenes. In conclusion, this H. petiolare cultivation under the applied moderate drought condition could lead to a double benefit i.e., water-saving irrigation practice and high quality metabolite production. [ABSTRACT FROM AUTHOR]

The main constituents of essential oil (EO) of Origanum syriacum L. collected from cultivated and growing wild in Sinai, Egypt were identified and determined by GC–MS. The antimicrobial activity of these essential oils against Gram positive and Gram negative bacterial strains was studied. The antimycotic activity of these EOs was also evaluated against eight fungal strains isolated from different sources. Forty-six compounds were identified in the EO of both samples, dominated by carvacrol in cultivated type. Thymol, γ-terpinene, linalool and 4-terpineol were the most represented constituents in O. syriacum plants collected from wild populations. Both EOs showed antibacterial activity with varying magnitudes, while EO from cultivated O. syriacum showed high antibacterial activity against Staphylococcus aureus with an inhibition zone of 32 ± 4.0 mm. Both EOs showed good antifungal activity against all fungal strains. O. syriacum EO from cultivated plants showed the lowest MIC 0.25 mg/L with Aspergillus fumigates clinical strain isolated either with Aspergillus flavus. [ABSTRACT FROM AUTHOR]