An Insight into Salvia haematodes L. (Lamiaceae) Bioactive Extracts Obtained by Traditional and Green Extraction Procedures

Even though Salvia is one of the most known genera of the Lamiaceae family, some traditionally used Salvia species are still now less investigated. To that end, the present study aims to evaluate the chemical profile and the potential bioactivities of extracts and related fractions obtained from the endemic sage Salvia haematodes L. by applying a traditional extraction method such as Soxhlet apparatus (SHS) and the rapid solid–liquid dynamic extraction (RSLDE) by Naviglio extractor^® (SHN), considered among the “green techniques” operating at room temperature and with minimum solvent employment and minimum energy. Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activity was measured by a modified Ellman’s method. The antioxidant activity was investigated by using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), ferric reducing ability power (FRAP), and β-carotene bleaching tests. The SHN methanol fraction resulted the most active in all assays in particular in inhibiting lipid peroxidation with IC₅₀ of 1.7 and 1.6 μg/mL, respectively, after 30 and 60 min of incubation. The SHN n-hexane fraction exhibited a selective activity against AChE with half-maximal inhibitory concentration (IC₅₀) of 22.9 μg/mL, while the SHS n-hexane extract was more active against BChE (IC₅₀ of 30.9 μg/mL). Based on these results, these fractions were subjected to further bio-fractionation by Medium Pressure Liquid Chromatography (MPLC) and the relative obtained fractions were investigated for their AChE and BChE inhibitory activity. A comparative analysis with bio-activity and chemical profile was performed. The observed biological effects provided us with a good starting point for further studies on S. haematodes extracts and fractions such as agents beneficial for the treatment of AD.

Inhibitory Activities of Sulfur Compounds in Garlic Essential Oil against Alzheimer's Disease-Related Enzymes and Their Distribution in the Mouse Brain

Alzheimer's disease (AD) is the most common neurodegenerative disease. Garlic reportedly has various physiological effects, including a role in protecting against dementia. However, the action mechanisms of garlic on AD are not entirely clear. In this study, we investigated the inhibitory activity of garlic essential oil (GEO) against AD-related enzymes and evaluated the distribution of active substances in GEO to the brain. We found that several sulfur compounds in GEO significantly inhibited AD-related enzymes. Sulfur compounds were detected in the serum and brain 6 h post administration. The ratios of allyl mercaptan (24.0 ± 3.9%) and allyl methyl sulfide (49.8 ± 15.6%) in the brain were significantly higher than those in GEO, while those of dimethyl trisulfide (0.89 ± 34.8%), allyl methyl trisulfide (0.41 ± 19.0%), and diallyl trisulfide (0.43 ± 72.8%) in the brain were significantly lower than those in GEO. Similar results were observed in the serum, suggesting that the organosulfur compounds were converted to allyl mercaptan or allyl methyl sulfide in the body. Although allyl mercaptan and allyl methyl sulfide are not the main components of GEO, they might be key molecules to understand the bioactivities of GEO in the body.

Essential Oils as a Potential Neuroprotective Remedy for Age-Related Neurodegenerative Diseases: A Review

Despite the improvements in life expectancy, neurodegenerative conditions have arguably become the most dreaded maladies of older people. The neuroprotective and anti-ageing potentials of essential oils (EOs) are widely evaluated around the globe. The objective of this review is to analyse the effectiveness of EOs as neuroprotective remedies among the four common age-related neurodegenerative diseases. The literature was extracted from three databases (PubMed, Web of Science and Google Scholar) between the years of 2010 to 2020 using the medical subject heading (MeSH) terms "essential oil", crossed with "Alzheimer's disease (AD)", "Huntington's disease (HD)", "Parkinson's disease (PD)" or "amyotrophic lateral sclerosis (ALS)". Eighty three percent (83%) of the studies were focused on AD, while another 12% focused on PD. No classifiable study was recorded on HD or ALS. EO from Salvia officinalis has been recorded as one of the most effective acetylcholinesterase and butyrylcholinesterase inhibitors. However, only Cinnamomum sp. has been assessed for its effectiveness in both AD and PD. Our review provided useful evidence on EOs as potential neuroprotective remedies for age-related neurodegenerative diseases.