Influence of Climate-Related Environmental Stresses on Economically Important Essential Oils of Mediterranean Salvia sp

Chemical Profiling and Antioxidant and Anti-Amyloid Capacities of Salvia fruticosa Extracts from Greece

An increasingly common ailment in elderly persons is Alzheimer's disease (AD), a neurodegenerative illness. Present treatment is restricted to alleviating symptoms; hence, there is a requirement to develop an effective approach to AD treatment. Salvia fruticosa (SF) is a medicinal plant with a documented neuroprotective potential. To identify extracts of increased neuroprotectivity, we partitioned the methanolic extract of SF aerial parts from Greece into several fractions, by employing solvents of different polarities. The fractions were chemically identified and evaluated for their antioxidancy and anti-neurotoxic potential against amyloid beta peptides 25-35 (Aβ25-35). Carnosol and carnosic acid were among the prominent compounds, while all partitions showed significant antioxidant capacity, with the diethyl ether and ethyl acetate partitions being the most potent. These, along with the aqueous and the butanolic fractions, demonstrated statistically significant anti-neurotoxic potential. Thus, our findings further validate the neuroprotective potential of SF and support its ethnopharmacological usage as an antioxidant. The particular properties found define SF as a promising source for obtaining extracts or bioactive compounds, possibly beneficial for generating AD-related functional foods or medications. Finally, our results encourage plant extract partitioning for acquiring fractions of enhanced biological properties.

Essential oil composition and antimicrobial potential of aromatic plants grown in the mid-hill conditions of the Western Himalayas

Essential oils are highly concentrated natural extracts obtained from plants, rich in bioactive constituents with antimicrobial properties, but the distinctive climate of the Western Himalayan region influences the same. Aromatic and medicinal plants, viz., Origanum majorana, Origanum vulgare, Cymbopogon winterianus, Pelargonium graveolens, and Nepeta cataria were grown in the foothills of the Western Himalayan condition and evaluated for essential oil content, composition, and their effect on some of the most common pathogenic microorganisms. The essential oil content (%) was 0.77, 0.45, 1.37, 0.15 and 0.17% in O. majorana, O. vulgare, C. winterianus, P. graveolens, and N. cataria, respectively. The major essential oil constituents of the isolated oils were terpinen-4-ol, thymol, citronellal, citronellol, and nepetalactone, contributing 41.24%, 31.81%, 43.13%, 43.35% and 91.43% in O. majorana, O. vulgare, C. winterianus, P. graveolens, and N. cataria, respectively. Well-diffusion assay revealed that the essential oil of O. majorana and O. vulgare was active against both the tested Gram-positive, viz., Bacillus subtilis MTCC 121, Micrococcus luteus MTCC 2470, and Staphylococcus aureus MTCC 96; and Gram-negative, viz., Escherichia coli MTCC 43, Klebsiella pneumoniae MTCC 109, and Pseudomonas aeruginosa MTCC 2453 bacteria, while the essential oil of C. winterianus, P. graveolens, and N. cataria showed activity against only some Gram-positive bacteria. Minimum inhibitory concentration (v/v) values indicated the highest efficacy of O. majorana essential oil against B. subtilis (0.5%), M. luteus (1%), and S. aureus (1%), while O. vulgare was most efficient to E. coli (2%) and K. pneumoniae (2%). C. winterianus essential oil did not inhibit any bacterial strains. M. luteus was susceptible to the essential oil of P. graveolens (1%) and N. cataria (0.5%) at low concentrations. Present findings showed the association between the chemical constituents' profile of isolated essential oils from the Himalayan region and their antimicrobial activity, indicating their perspective to be utilized as antibacterial means.

Deciphering the effects of genotype and climatic factors on the performance, active ingredients and rhizosphere soil properties of Salvia miltiorrhiza

Introduction

Salvia miltiorrhiza Bunge is an important medicinal herb, which is widely cultivated in most parts of China. It has attracted considerable attention because of its pharmacological properties and potential health benefits.

Methods

We used a field experiment to determine the effects of different genotypes and climatic factors on the performance (plant biomass, morphological parameters), active ingredients, rhizosphere soil physicochemical properties and microbial composition of S. miltiorrhiza at five cultivation locations.

Results

The results showed that these parameters were significantly different in the six different genotypes of S. miltiorrhiza from five producing areas. Genotype and soil physicochemical properties were the main factors affecting the growth traits of S. miltiorrhiza, while genotype, climate and soil physicochemical properties were the main factors affecting the content of active components of S. miltiorrhiza. Microbial phospholipid fatty acid analysis showed that the biomass of Gram-positive and Gram-negative bacteria was affected by the genotypes of S. miltiorrhiza plants, while the biomass of arbuscular mycorrhizal fungi, fungi, Gram-positive and Gram-negative bacteria was affected by climate factors.

Discussion

Based on the main results, DS993 was the most suitable genotype for S. miltiorrhiza in the five producing areas from the perspective of comprehensive growth traits and medicinal components, while DS993 and DS2000 were suitable for planting in Shandong province from the perspective of origin. DS996 is not suitable for all of the above production areas. These results are helpful to understand the ecological adaptability of different genotypes of S. miltiorrhiza resources, and to select appropriate S. miltiorrhiza genotypes for specific planting areas, so as to maximize yield and quality.

A Hormetic Spatiotemporal Photosystem II Response Mechanism of Salvia to Excess Zinc Exposure

Exposure of Salvia sclarea plants to excess Zn for 8 days resulted in increased Ca, Fe, Mn, and Zn concentrations, but decreased Mg, in the aboveground tissues. The significant increase in the aboveground tissues of Mn, which is vital in the oxygen-evolving complex (OEC) of photosystem II (PSII), contributed to the higher efficiency of the OEC, and together with the increased Fe, which has a fundamental role as a component of the enzymes involved in the electron transport process, resulted in an increased electron transport rate (ETR). The decreased Mg content in the aboveground tissues contributed to decreased chlorophyll content that reduced excess absorption of sunlight and operated to improve PSII photochemistry (Φ_PSII), decreasing excess energy at PSII and lowering the degree of photoinhibition, as judged from the increased maximum efficiency of PSII photochemistry (Fv/Fm). The molecular mechanism by which Zn-treated leaves displayed an improved PSII photochemistry was the increased fraction of open PSII reaction centers (qp) and, mainly, the increased efficiency of the reaction centers (Fv′/Fm′) that enhanced ETR. Elemental bioimaging of Zn and Ca by laser ablation–inductively coupled plasma–mass spectrometry (LA–ICP–MS) revealed their co-localization in the mid-leaf veins. The high Zn concentration was located in the mid-leaf-vein area, while mesophyll cells accumulated small amounts of Zn, thus resembling a spatiotemporal heterogenous response and suggesting an adaptive strategy. These findings contribute to our understanding of how exposure to excess Zn triggered a hormetic response of PSII photochemistry. Exposure of aromatic and medicinal plants to excess Zn in hydroponics can be regarded as an economical approach to ameliorate the deficiency of Fe and Zn, which are essential micronutrients for human health.