Seven Compounds from Turmeric Essential Oil Inhibit Three Key Proteins Involved in SARS-CoV-2 Cell Entry and Replication in silico

Introduction: Turmeric rhizome (Cucurma longa L.) has showed great potential as a traditional drug in folk medicine of several countries. In light of the prominent use of turmeric rhizome in treating both respiratory and viral diseases, we aimed to dock major compounds from the essential oil of turmeric against three key proteins involved in COVID-19 cell entry and replication. Methods: The essential oil of turmeric rhizome was obtained using a hydrodistillation technique, and the chemical characterization of the oil was investigated using GC-MS/GC-FID. Then, main compounds were docked with the key proteins of COVID-19. Results: A total of 26 components were identified in the essential oil extracted from the rhizomes via GC-MS/GC-FID. Seven dominant compounds (turmerone (31.4%), ar-turmerone (16.1%), turmerol (14.6%), terpinolene (11.0%), α-zingiberene (5.2%), β-sesquiphellandrene (4.8%), and β-caryophyllene (3.5%)) were docked against COVID-19 main protease, papain-like protease (PLpro), spike protein and 3C-like protease (3CLpro), and the best inhibitor was picked according to the calculated binding affinity and non-bonding interactions with the protein active site. β-sesquiphellandrene and α-zingiberene showed highest besides the same binding affinity towards COVID-19 virus (-6.38 and -6.39kcal/mol, respectively). α-zingiberene was found to bind at the active site of the COVID-19 protein and interacted with different non-bonding interactions, while turmerol showed the highest affinity (-5.78kcal/mol) against CLpro enzyme by binding with Met165, Leu141, Met49, Ser144, Cys145, and Glu166 residues. Conclusion: The essential oil of turmeric harbors a blend of potentially bioactive compounds that may be considered as a good target against COVID-19 virus and warrants further experimental studies

Comprehensive biological and chemical evaluation of two seseli species (S. gummiferum and s. transcaucasicum)

Seseli L. is one of the largest genera of the Apiaceae family widely known for their traditional uses as herbal remedies. In the present study, the methanolic and water extracts of two Seseli species, S. gummiferum and S. transcaucasicum were evaluated for their bioactive contents and biological activities. The total phenolic and flavonoid contents in the extracts ranged from 19.09 to 24.33 mg GAE/g and from 0.45 to10.09 mg RE/g, respectively. Moreover, while narcissin was detected as the most abundant component in the methanolic extract of S. transcaucasicum (261.40 µg/g), chlorogenic acid was identified as the major component in all the other extracts, although a high amount was also present in the methanolic S. transcaucasicum extract (107.48–243.12 µg/g). The total antioxidant capacity was also determined by the phosphomolybdenum assay (0.66–1.18 mM TE/g). Other antioxidant assays such as the radical scavenging assays (DPPH: 5.51–11.45 mg TE/g; ABTS: 43.46–51.91 mg TE/g), reducing assays (CUPRAC: 41.67–53.20 mg TE/g; FRAP: 31.26–34.14 mg TE/g), as well as the metal chelating activity assay (14.38–38.57 mg EDTAE/g) were conducted. All the extracts showed inhibitory potential against the enzyme’s amylase (0.12–0.78 mM ACAE/g), acetyl-and butyryl-cholinesterase (0.15–9.71 mg GALAE/g), while only the methanolic extracts acted as inhibitors of tyrosinase (107.15 and 109.37 mg KAE/g) and only the water extract of S. gummiferum displayed anti-glucosidase activity (0.13 mM ACAE/g). Interestingly, the methanolic extracts of both Seseli species showed lower cytotoxicity towards HaCaT cells (IC50: >500 µg/mL), compared to the water extracts (IC50: 267.8 and 321.41 µg/mL). Besides, only the methanolic extracts showed a slight wound healing effect (28.21 and 31.23%). All extracts showed antibacterial action against Staphylococcus lugdunensis (minimum inhibitory and bactericidal concentrations: 0.025–2 mg/mL). S. gummiferum methanolic extract, which exhibited the highest antibacterial potency was found to inhibit adhesion and invasion of S. lugdunensis to HaCaT cells as well. Taken together, this study demonstrated the two Seseli species to harbour interesting bioactive components, in particular polyphenolics and to exhibit several biological properties that could be further investigated for their potential exploitation as healing agents as supported by various traditional medicinal uses

Which Extraction Solvents and Methods Are More Effective in Terms of Chemical Composition and Biological Activity of Alcea fasciculiflora from Turkey?

The bioactive content, antioxidant properties, and enzyme inhibition properties of extracts of Alcea fasciculiflora from Turkey prepared with different solvents (water, methanol, ethyl acetate) and extraction methods (maceration, soxhlet, homogenizer assisted extraction, and ultrasound assisted extraction) were examined in this study. UHPLC-HRMS analysis detected or annotated a total of 50 compounds in A. fasciculiflora extracts, including 18 hydroxybenzoic and hydroxycinnamic acids, 7 Hexaric acids, 7 Coumarins, 15 Flavonoids, and 3 hydroxycinnamic acid amides. The extracts had phenolic and flavonoid levels ranging from 14.25 to 24.87 mg GAE/g and 1.68 to 25.26 mg RE/g, respectively, in the analysis. Both DPPH and ABTS tests revealed radical scavenging capabilities (between 2.63 and 35.33 mg TE/g and between 13.46 and 76.27 mg TE/g, respectively). The extracts had reducing properties (CUPRAC: 40.38–78 TE/g and FRAP: 17.51–42.58 TE/g). The extracts showed metal chelating activity (18.28–46.71 mg EDTAE/g) as well as total antioxidant capacity (phosphomolybdenum test) (0.90–2.12 mmol TE/g). DPPH, ABTS, FRAP, and metal chelating tests indicated the water extracts to be the best antioxidants, while the ethyl acetate extracts had the highest overall antioxidant capacity regardless of the extraction technique. Furthermore, anti-acetylcholinesterase activity was identified in all extracts (0.17–2.80 mg GALAE/g). The water extracts and the ultrasound-assisted ethyl acetate extract were inert against butyrylcholinesterase, but the other extracts showed anti-butyrylcholinesterase activity (1.17–5.80 mg GALAE/g). Tyrosine inhibitory action was identified in all extracts (1.79–58.93 mg KAE/g), with the most effective methanolic extracts. Only the ethyl acetate and methanolic extracts produced by maceration and homogenizer aided extraction showed glucosidase inhibition (0.11–1.11 mmol ACAE/g). These findings showed the overall bioactivity of the different extracts of A. fasciculiflora and provided an overview of the combination of solvent type and extraction method that could yield bioactive profile and pharmacological properties of interest and hence, could be a useful reference for future studies on this species

Shining the spotlight on NMR metabolic profiling and bioactivities of different solvent extracts of Piliostigma thonningii

Piliostigma thonningii (Fabaceae) is a versatile medicinal plant used as a traditional remedy, especially in African countries. In the present study, ethyl acetate, methanolic and water extracts of different parts of (fruits, leaves, stem barks) P. thonningii were evaluated for their bioactive contents, enzyme inhibitory, antioxidant and antimicrobial activities. Antioxidant potentials were also displayed in various methods like phosphomolybdenum assay (0.79-5.94 mmol TE/g), radical scavenging assays (DPPH: 20.39-471.28 mg TE/g; ABTS: 42.43-654.14 mg TE/g); reducing assays (CUPRAC: 102.98-1207.42 mg TE/g; FRAP: 45.30-656.25 mg TE/g) and metal chelating activity (2.55-22.32 mg EDTAE/g). In particular, the methanolic and water extracts showed better antioxidant potential. Except for a few, the extracts were also found to act as inhibitors of enzymes such as acetylcholinesterase (2.35-5.35 mg GALAE/g), butyrylcholinesterase (0.83-13.80 mg GALAE/g), tymsinase (4.03-143.86 mg KAE/g), amylase (0.21-1.39 mmol ACAE/g) and glucosidase (3.52-7.13 mmol ACAE/g). Additionally, all the tested extracts possessed significant antibacterial (minimum inhibitory concentration (MIC) and minimum bactericidal concentration: 0.11-0.61 mg/ml) and antifungal (MIC and minimum fungicidal concentration: 0.04-0.61 mg/ml) effects. Indeed, the data garnered from the present study provides a bright scope for the advanced investigation on this particular plant possessing pharmacologically active traits