Chemical Profiling and Biological Properties of Essential Oils of Lavandula stoechas L. Collected from Three Moroccan Sites: In Vitro and In Silico Investigations

The aim of this study was the determination of the chemical compounds of Lavandula stoechas essential oil from Aknol (LSEO_A), Khenifra (LSEO_K), and Beni Mellal (LSEO_B), and the in vitro investigation of their antibacterial, anticandidal, and antioxidant effects, and in silico anti-SARS-CoV-2 activity. The chemical profile of LSEO was determined using GC-MS-MS analysis, the results of which showed a qualitative and quantitative variation in the chemical composition of volatile compounds including L-fenchone, cubebol, camphor, bornyl acetate, and τ-muurolol; indicating that the biosynthesis of essential oils of Lavandula stoechas (LSEO) varied depending on the site of growth. The antioxidant activity was evaluated using the ABTS and FRAP methods, our results showed that this tested oil is endowed with an ABTS inhibitory effect and an important reducing power which varies between 4.82 ± 1.52 and 15.73 ± 3.26 mg EAA/g extract. The results of antibacterial activity of LSEO_A, LSEO_K and LSEO_B, tested against Gram-positive and Gram-negative bacteria, revealed that B. subtilis (20.66 ± 1.15-25 ± 4.35 mm), P. mirabilis (18.66 ± 1.15-18.66 ± 1.15 mm), and P. aeruginosa (13.33 ± 1.15-19 ± 1.00 mm) are the most susceptible strains to LSEO_A, LSEO_K and LSEO_B of which LSEO_B exhibits bactericidal effect against P. mirabilis. furthermore The LSEO exhibited varying degrees of anticandidal activity with an inhibition zones of 25.33 ± 0.5, 22.66 ± 2.51, and 19 ± 1 mm for LSEO_K, LSEO_B, and LSEO_A, respectively. Additionally, the in silico molecular docking process, performed using Chimera Vina and Surflex-Dock programs, indicated that LSEO could inhibit SARS-CoV-2. These important biological properties of LSEO qualify this plant as an interesting source of natural bioactive compounds with medicinal actions.

UHPLC-MS Chemical Fingerprinting and Antioxidant, Antiproliferative, and Enzyme Inhibition Potential of Gaultheria pumila Berries

Gaultheria pumila (Ericaceae) (known as Chaura or Mutilla) is a Chilean native small shrub that produces berry fruits consumed by local Mapuche people. In this study, the chemical fingerprinting and antioxidant, enzyme inhibition, and antiproliferative activities of the berries were investigated for the first time. Thirty-six metabolites were identified in the fruits by ultra-high performance liquid chromatography-photodiode array detection, hyphenated with Orbitrap mass spectrometry analysis (UHPLC-DAD-Orbitrap-MS). Metabolites, included anthocyanins, phenolic acids, flavonoids, iridoids, diterpenes, and fatty acids. Moderate inhibitory activities against acetylcholinesterase (7.7 ± 0.3 µg/mL), butyrylcholinesterase (34.5 ± 0.5 µg/mL), and tyrosinase (3.3 ± 0.2 µg/mL) enzymes were found. Moreover, selected major compounds were subjected to docking assays in light of their experimental inhibition. Results indicated that hydrogen bonding, π–π interaction, and a salt bridge interaction contributed significantly. Gaultheria pumila berries showed a total phenolic content of 189.2 ± 0.2 mg of gallic acid equivalents/g, total flavonoid content of 51.8 ± 0.1 mg quercetin equivalents/g, and total anthocyanin content of 47.3 ± 0.2 mg of cianydin-3-glucoside equivalents/g. Antioxidant activity was assessed using DPPH (92.8 ± 0.1 µg/mL), FRAP (134.1 ± 0.1 μmol Trolox equivalents/g), and ORAC (4251.6 ± 16.9 μmol Trolox equivalents/g) assays. Conversely, Gaultheria pumila showed a scarce antiproliferative potential against several solid human cancer cells. Our findings suggest that Gaultheria pumila berries have several bioactive metabolites with inhibitory effects against acetylcholinesterase, butyrylcholinesterase, and tyrosinase, and have the potential for use in food supplements.

Phenolic Fingerprinting, Antioxidant, and Deterrent Potentials of Persicaria maculosa Extracts

Persicaria maculosa (Polygonaceae) (known as lady’s thumb) is an annual morphologically variable weed that is widely distributed in Chile. The purpose of this study was to investigate the antifeedant potential of methanolic (MeOH), ethanolic (EtOH), and dichloromethane (DCM) extracts from the aerial parts of this plant collected in the Valparaíso and Curicó provinces (Chile) and relate this activity to the antioxidant capacity and the presence of phenolic compounds in the extracts. A phenolic profile based on HPLC-ESI-MS/MS allowed the identification of 26 phenolic compounds, most of them glycosyl derivatives of isorhamnetin, quercetin, and kaempferol. In addition, the total phenolic content (TP), total flavonoids (TF), and antioxidant activity measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH), superoxide anion scavenging (O₂⁻), ferric-reducing antioxidant power (FRAP), and cupric-reducing antioxidant capacity (CUPRAC) of the extracts are reported. The antifeedant potentials of the plant extracts were tested against Epilachna paenulata, Pseudaletia adultera, Macrosiphum euphorbiae, and Diaphorina citri insects for the first time. The activity against the aphid M. euphorbiae was significant for the DCM extracts of plants from Valparaíso and Curicó (settling % = 23% ± 4% and 23% ± 5%, respectively). The antifeedant activities against the beetle E. paenulata and the lepidoptera P. adultera were significant for Valparaíso extracts, especially when tested against E. Paenulata (IFP = 1.0 ± 0.0). Finally, the MeOH and EtOH extracts from Valparaíso plants reduced the diet consumption of the psilid D. citri (p < 0.05). The results showed that P. maculosa is a good source of flavonoids with some antioxidant capacities and has potential interest as botanical eco-friendly alternative with deterrent activity.

Insights into the interactions between maleimide derivates and GSK3β combining molecular docking and QSAR

Many protein kinase (PK) inhibitors have been reported in recent years, but only a few have been approved for clinical use. The understanding of the available molecular information using computational tools is an alternative to contribute to this process. With this in mind, we studied the binding modes of 77 maleimide derivates inside the PK glycogen synthase kinase 3 beta (GSK3β) using docking experiments. We found that the orientations that these compounds adopt inside GSK3β binding site prioritize the formation of hydrogen bond (HB) interactions between the maleimide group and the residues at the hinge region (residues Val135 and Asp133), and adopt propeller-like conformations (where the maleimide is the propeller axis and the heterocyclic substituents are two slanted blades). In addition, quantitative structure–activity relationship (QSAR) models using CoMSIA methodology were constructed to explain the trend of the GSK3β inhibitory activities for the studied compounds. We found a model to explain the structure–activity relationship of non-cyclic maleimide (NCM) derivatives (54 compounds). The best CoMSIA model (training set included 44 compounds) included steric, hydrophobic, and HB donor fields and had a good Q² value of 0.539. It also predicted adequately the most active compounds contained in the test set. Furthermore, the analysis of the plots of the steric CoMSIA field describes the elements involved in the differential potency of the inhibitors that can be considered for the selection of suitable inhibitors.

Docking and quantitative structure-activity relationship of oxadiazole derivates as inhibitors of GSK3β

The binding modes of 42 oxadiazole derivates inside glycogen synthase kinase 3 beta (GSK3β were determined using docking experiments; thus, the preferred active conformations of these inhibitors are proposed. We found that these compounds adopt a scorpion-shaped conformation and they accept a hydrogen bond (HB) from the residue Val135 of the GSK3β ATP-binding site hinge region. In addition, quantitative structure-activity relationship (QSAR) models were constructed to explain the trend of the GSK3β inhibitory activities for the studied compounds. In a first approach, three-dimensional (3D) vectors were calculated using docking conformations and, by using multiple-linear regression, we assessed that GETAWAY vectors were able to describe the reported biological activities. In other QSAR approach, SMILES-based optimal descriptors were calculated. The best model included three-SMILES elements SSSβ leading to the identification of key molecular features that contribute to a high GSK3β inhibitory activity.