Chemical Composition of Thymus leucotrichus var. creticus Essential Oil and Its Protective Effects on Both Damage and Oxidative Stress in Leptodictyum riparium Hedw. Induced by Cadmium

Chemical Composition of Salvia fruticosa Mill. Essential Oil and Its Protective Effects on Both Photosynthetic Damage and Oxidative Stress in Conocephalum conicum L. Induced by Environmental Heavy Metal Concentrations

The genus Salvia L., belonging to the Lamiaceae family, contains more than 900 species distributed in various parts of the world. It is a genus containing aromatic plants used both in the culinary field and above all in the cosmetic area to produce several perfumes. Salvia fruticosa Mill., notoriously known as Greek Salvia, is a plant used since ancient times in traditional medicine, but today cultivated and used in various parts of Europe and Africa. Polar and apolar extracts of this plant confirmed the presence of several metabolites such as abietane and labdane diterpenoids, triterpenoids, steroids, and some flavonoids, causing interesting properties such as sedative, carminative, and antiseptic, while its essential oils (EOs) are mainly characterized by compounds such as 1,8-cineole and camphor. The aim of this work concerns the chemical analysis by GC and GC-MS, and the investigation of the biological properties, of the EO of S. fruticosa plants collected in eastern Sicily. The gas-chromatographic analysis confirmed the presence of 1,8-cineole (17.38%) and camphor (12.81%), but at the same time, also moderate amounts of α-terpineol (6.74%), β-myrcene (9.07%), camphene (8.66%), β-pinene (6.55%), and α-pinene (6.45%). To study the protective effect of EOs from S. fruticosa (both the total mixture and the individual compounds) on possible damage induced by heavy metals, an in vitro system was used in which a model organism, the liverwort Conocephalum conicum, was subjected to the effect of a mix of heavy metals (HM) prepared using values of concentrations actually measured in one of the most polluted watercourses of the Campania region, the Regi Lagni. Finally, the antioxidant response and the photosynthetic damage were examined. The exogenous application of the EO yields a resumption of the oxidative stress induced by HM, as demonstrated by the reduction in the Reactive Oxygen Species (ROS) content and by the increased activity of antioxidant enzyme catalase (CAT) and glutathione-S-transferase (GST). Furthermore, plants treated with HMs and EO showed a higher Fv/Fm (maximal quantum efficiency of PSII in the dark) with respect to HMs-only treated ones. These results clearly indicate the protective capacity of the EO of S. fruticosa against oxidative stress, which is achieved at least in part by modulating the redox state through the antioxidant pathway and on photosynthetic damage.

Thymus richardii subsp. nitidus (Guss.) Jalas Essential Oil: An Ally against Oral Pathogens and Mouth Health

The genus Thymus L., belonging to the Lamiaceae family, contains about 220 species with a distribution that mainly extends in Europe, northwest Africa, Ethiopia, Asia, and southern Greenland. Due to their excellent biological properties, fresh and/or dried leaves and aerial parts of several Thymus ssp. have been utilized in the traditional medicine of many countries. To evaluate not only the chemical aspects but also the biological properties, the essential oils (EOs), obtained from the pre-flowering and flowering aerial parts of Thymus richardii subsp. nitidus (Guss.) Jalas, endemic to Marettimo Island (Sicily, Italy), were investigated. The chemical composition of the EOs, obtained by classical hydrodistillation and GC-MS and GC-FID analyses, showed the occurrence of similar amounts of monoterpene hydrocarbons, oxygenated monoterpenes, and sesquiterpene hydrocarbons. The main constituents of the pre-flowering oil were β-bisabolene (28.54%), p-cymene (24.45%), and thymol methyl ether (15.90%). The EO obtained from the flowering aerial parts showed as principal metabolites β-bisabolene (17.91%), thymol (16.26%), and limonene (15.59%). The EO of the flowering aerial parts, and its main pure constituents, β-bisabolene, thymol, limonene, p-cymene, and thymol methyl ether were investigated for their antimicrobial activity against oral pathogens and for their antibiofilm and antioxidant properties.

The Antioxidant Properties and Protective Capacity of Prangos trifida and Cachrys cristata Essential Oils against Cd Stress in Lunularia cruciata and Brassica napus

The genera Prangos Lindl. and Cachrys L., for a long time interpreted as a single genus but today distinct and separate, and both belonging to the majestic Apiaceae family, are species with a large distribution and are used in ethnomedicine in various countries, especially in Asian countries. In this context, we investigated the chemical characteristics and biological properties of two essential oils (EOs) obtained from different specimens, namely Cachrys cristata (Cc) and Prangos trifida (Pt). The chemical composition of the two EOs was investigated by GC-MS analysis. From gas-chromatography analyses, while the (Cc) EO was rich in β-myrcene (45.34%), allo-ocimene (10.90%), and 2,4,6-trimethylbenzaldehyde (23.47%), the (Pt) EO was characterized by moderate amounts of α-pinene (8.85%), sylvestrene (11.32%), α-phellandrene (12.14%), (Z)-β-ocimene (18.12%), and finally, p-mentha-1,3,8-triene (9.56%). Furthermore, the protective and antioxidant capacity of (Pt) and (Cc) EOs on Lunularia cruciata and Brassica napus exposed to cadmium (Cd) stress was studied. To study these possible effects, the liverwort and oilseed rape, previously pretreated with both EOs, were subsequently subjected to oxidative stress by treatment with Cd. Then, DNA damage and antioxidant enzyme activity were measured in both EOs-pretreated and untreated samples to examine EOs-induced tolerance to Cd toxicity. The results indicate that (Pt) and (Cc) EOs have antioxidant and protective capacity in modulating the redox state through the antioxidant pathway by reducing oxidative stress induced by Cd. Furthermore, B. napus was found to be a more resistant and tolerant species than L. cruciata.