GC-MS Chemical Profiling, Biological Investigation of Three Salvia Species Growing in Uzbekistan.

Salvia is a potentially valuable aromatic herb that has been used since ancient times. The present work studied the chemical profile of three Salvia species essential oils (EO): S. officinalis, S. virgata and S. sclarea, as well as assessing their antioxidant and enzyme inhibitory activities. A total of 144 compounds were detected by GC-MS analysis, representing 91.1, 84.7 and 78.1% in S. officinalis, S. virgata and S. sclarea EOs, respectively. The major constituents were cis-thujone, 2,4-hexadienal and 9-octadecenoic acid, respectively. The principal component analysis (PCA) score plot revealed significant discrimination between the three species. The antioxidant activity of the EOs was evaluated using in vitro assays. Only S. virgata EO showed antioxidant activity in the 2,2-diphenyl-1-picryl-hydrazyl (DPPH) assay (26.6 ± 1.60 mg Trolox equivalent (TE)/g oil). Moreover, this oil exhibited the highest antioxidant activity in 2,2-azino bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), cupric-reducing antioxidant capacity (CUPRAC) and ferric-reducing power (FRAP) assays in comparison with the other two EOs (190.1 ± 2.04 vs. 275.2 ± 8.50 and 155.9 ± 1.33 mg TE/g oil, respectively). However, S. virgata oil did not show any effect in the chelating ability assay, while in the PBD assay, S. officinalis had the best antioxidant activity (26.4 ± 0.16 mmol TE/g oil). Enzyme inhibitory effect of the EOs was assessed against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), tyrosinase, α-glucosidase and α-amylase. AChE enzyme was more sensitive to S. officinalis EO (4.2 ± 0.01 mg galantamine equivalent (GALAE)/g oil), rather than S. virgata EO, which was ineffective. However, S. virgata had the highest BChE effect (12.1 ± 0.16 mg GALAE/g oil). All studied oils showed good tyrosinase inhibitory activity, ranging between 66.1 ± 0.61 and 128.4 ± 4.35 mg kojic acid equivalent (KAE)/g oil). Moreover, the EOs did not exhibit any glucosidase inhibition and were weak or inefficient on amylase enzyme. Partial least squares regression (PLS-R) models showed that there is an excellent correlation between the antioxidant activity and the volatile profile when being compared to that of enzyme inhibitory activity. Thus, the studied Salvia essential oils are interesting candidates that could be used in drug discovery for the management of Alzheimer's and hyperpigmentation conditions.

Ecdysteroids as Potent Enzyme Inhibitors and Verification of Their Activity Using In Vitro and In Silico Docking Studies.

Ecdysteroids represent arthropods' steroidal hormones, and they exist in about 5-6% of plant species. In this study, the enzyme inhibitory activity of 20 ecdysteroids was assessed for the first time via determining their inhibition versus acetylcholinesterase, butyrylcholinesterase, tyrosinase, as well as α-amylase enzymes. Furthermore, 20-Hydroxyecdysone-2,3,22-tri-O-acetate (4) showed the highest inhibition of acetylcholinesterase and butyrylcholinesterase with values of 5.56 and 4.76 mg GALAE/g, respectively. All ecdysteroids displayed tyrosinase inhibitory effects, whereas the most potent was viticosterone E (7) with 78.88 mg KAE/g. Most ecdysteroids had similar amylase inhibitory properties; meanwhile, the best α-amylase inhibitory potential was observed with viticosterone E-diacetonide (18) (0.35 mmol ACAE/g). Most of the tested compounds showed tyrosinase inhibitory potential; therefore, they were exposed to molecular docking evaluation using the tyrosinase enzyme. Viticosterone E (7) showed the best ranking score with a docking score of -5.716 Kcal/mol and made three separate H-bonds with Gly281, Asn81, and His85. From ADMET /TOPKAT in silico evaluation, it was obvious that most of the compounds displayed reasonable pharmacodynamic and pharmacokinetic properties; however, their toxicity should be carefully monitored by adjusting their doses while investigating their activity after incorporation into dosage forms. Principal component analysis (PCA) based upon the in vitro and in silico data was carried out to visualize the differences between the tested compounds better. PCA score plot successfully classifies the compounds into four main clusters that, in turn, reflects the similarities and differences among the clustered compounds with respect to their biological, pharmacokinetic, and pharmacodynamic properties that are mainly influenced by the similarity in the chemical structure. Thus, ecdysteroids can act as effective drug entities for alleviating several disorders owing to their enzyme inhibitory potential.

GC-MS Based Identification of the Volatile Components of Six Astragalus Species from Uzbekistan and Their Biological Activity.

The compositions of volatile components in the aerial parts of six Astragalus species, namely A. campylotrichus (Aca), A. chiwensis (Ach), A. lehmannianus (Ale), A. macronyx (Ama), A. mucidus (Amu) and A. sieversianus (Asi), were investigated using gas chromatograph-mass spectrometry (GC-MS) analysis. Ninety-seven metabolites were identified, accounting for 73.28, 87.03, 74.38, 87.93, 85.83, and 91.39% of Aca, Ach, Ale, Ama, Amu and Asi whole oils, respectively. Sylvestrene was the most predominant component in Asi, Amu and Ama, with highest concentration in Asi (64.64%). In addition, (E)-2-hexenal was present in a high percentage in both Ale and Ach (9.97 and 10.1%, respectively). GC-MS based metabolites were subjected to principal component analysis (PCA) and hierarchal cluster analysis (HCA) to explore the correlations between the six species. The PCA score plot displayed clear differentiation of all Astragalus species and a high correlation between the Amu and Ama species. The antioxidant activity was evaluated in vitro using various assays, phosphomolybdenum (PM), 2,2 diphenyl-1-picryl-hydrazyl-hydrate (DPPH), 2,2-azino bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), cupric reducing antioxidant capacity (CUPRAC), ferric reducing power (FRAP) and ferrous ion chelation (FIC) assays. In addition, the potential for the volatile samples to inhibit both acetyl/butyrylcholinesterases (AChE, BChE), α- amylase, α-glucosidase and tyrosinase was assessed. Most of the species showed considerable antioxidant potential in the performed assays. In the DPPH assay, Ama exhibited the maximum activity (24.12 ± 2.24 mg TE/g sample), and the volatiles from Amu exhibited the highest activity (91.54 mgTE/g oil) in the ABTS radical scavenging assay. The effect was more evident in both CUPRAC and FRAP assays, where both Ale and Ama showed the strongest activity in comparison with the other tested species (84.06, 80.28 mgTE/g oil for CUPRAC and 49.47, 49.02 mgTE/g oil for FRAP, respectively). Asi demonstrated the strongest AChE (4.55 mg GALAE/g oil) and BChE (3.61 mg GALAE/g oil) inhibitory effect. Furthermore, the best tyrosinase inhibitory potential was observed for Ale (138.42 mg KAE/g). Accordingly, Astragalus species can be utilized as promising natural sources for many medicinally important components that could be tested as drug candidates for treating illnesses such as Alzheimer's disease, diabetes mellitus and oxidative stress-related diseases.