Chemical Analysis and Investigation of Biological Effects of Salvia officinalis Essential Oils at Three Phenological Stages.

Salvia officinalis is a medicinal plant used to treat some diseases, including microbial infections and diabetes. Different studies showed the biological and pharmacological properties of this species. The aim of this study was the determination of the chemical compounds of S. officinalis essential oils and the investigation of their antimicrobial, antioxidant, antidiabetic, and anti-inflammatory properties. The chemical compounds of S. officinalis were determined by GC-MS analysis. The antioxidant activity was assessed by DPPH, ABTS, H2O2, and FRAP assays. The in vitro antidiabetic effect was evaluated by the inhibition of α-amylase, α-glucosidase, and lipase activities, and the anti-inflammatory effect was evaluated using the 5-lipoxygenase assay. Moreover, antibacterial activity was assessed against six bacterial strains using agar well diffusion assay and microdilution method. The main compounds in essential oils of S. officinalis at three phenological stages were naphthalenone, camphor, 1.8-cineole, and α-thujone. The full flowering stage essential oil showed the best antioxidant activity with different IC50 values according to the used tests. This oil also exhibited important inhibitory effects at the full flowering stage against α-amylase (IC50 = 69.23 ± 0.1 µg/mL), α-glucosidase (IC50 = 22.24 ± 0.07 µg/mL), and lipase (IC50 = 37.3 ± 0.03 µg/mL). The 5-lipoxygenase inhibitory effect was the best at the full flowering stage (IC50 = 9.24 ± 0.03 µg/mL). The results of the antibacterial evaluation revealed that, at three seasonal periods, S. officinalis essential oil demonstrated strong antibacterial activity. Although the full flowering stage had the best antibacterial activity, there were no significant differences between the three stages. Additionally, the essential oils showed bactericidal effects on Listeria monocytogenes, Staphylococcus aureus, Bacillus subtilis, Proteus mirabilis, Escherichia coli, and Salmonella typhimurium, respectively. The findings of this work showed remarkably that S. officinalis synthesizes essential oils according to different developmental stages. Moreover, it has exhibited interesting biological and pharmacological properties justifying its medicinal effects and suggesting it as a very important source of natural drugs.

Towards the Pharmacological Validation and Phytochemical Profiling of the Decoction and Maceration of Bruguiera gymnorhiza (L.) Lam.-A Traditionally Used Medicinal Halophyte.

Decoctions (leaves and roots) of Bruguiera gymnorhiza (L.) Lam. are traditionally used against diabetes in many countries, including Mauritius. This study endeavoured to evaluate the inhibitory potential of leaves, roots, twigs and fruits extracts (decoction and maceration) of B. gymnorhiza against key enzymes relevant to diabetes. Considering complications related to diabetes, other clinical enzymes, namely, acetylcholinesterase (AChE), butyrylcholinesterase (BChE), tyrosinase, elastase and pancreatic lipase, were used. Identification of compounds was carried out using ultra-high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (UHPLC-ESI-MS/MS). Antioxidant capacities were assessed using DPPH, ABTS, FRAP, CUPRAC, phosphomolybdenum, metal chelating. The relationship between mode of extraction, plant parts and biological activities was determined using multivariate analysis. Macerated fruits, rich in phytochemicals (phenolic, flavanol, tannin, and triterpenoid), exhibited substantially high antioxidant capacities related to radical scavenging (DPPH: 547.75 ± 10.99 and ABTS: 439.59 ± 19.13 mg TE/g, respectively) and reducing potential (CUPRAC: 956.04 ± 11.90 and FRAP: 577.26 ± 4.55 mg TE/g, respectively). Additionally, the same extract significantly depressed AChE and BChE (3.75 ± 0.03 and 2.19 ± 0.13 mg GALAE/g, respectively), tyrosinase (147.01 ± 0.78 mg KAE/g), elastase (3.14 ± 0.08 mg OE/g) and amylase (1.22 ± 0.01 mmol ACAE/g) enzymatic activities. Phytochemical results confirmed the presence of 119 compounds in all maceration and 163 compounds in all decoction samples. The screening also revealed important compounds in the extracts, namely, quinic acid, brugierol, bruguierol A, epigallocatechin, chlorogenic acid, to name a few. Multivariate analysis reported that the plant parts of B. gymnorhiza greatly influenced the observed biological activities in contrast to the types of extraction methods employed. Docking calculations have supported the findings of the experimental part through the high binding affinity and strong interactions of some compounds against tyrosinase, AChE, BChE and elastase enzymes. The decocted root and leaf of B. gymnorhiza showed low to moderate antidiabetic activity, thereby partially supporting its traditional uses in the management of diabetes. However, the fruit, the most active organ, can be used as a diet supplement to reduce the risk of diabetes complications after evaluating its cytotoxic effects.