In silico screening of phenylethanoid glycosides, a class of pharmacologically active compounds as natural inhibitors of SARS-CoV-2 proteases

Rapidly screening of pancreatic lipase inhibitors from Sibiraea angustata (rehd.) Hand.-Mazz. leaves using affinity ultrafiltration combined with HPLC-QTOFMS, molecular docking, targeted separation, and in vitro experimental verification

An integrated strategy was proposed for the rapid screening of pancreatic lipase inhibitors from Sibiraea angustata (Rehd.) Hand.-Mazz. (S. angustata) leaves based on affinity ultrafiltration, high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (HPLC-QTOFMS), molecular docking, targeted separation and in vitro experimental verification. A total of fifteen target compounds, including five flavonoids, one phenylpropanol glycoside and nine terpenoids, had been screened as pancreatic lipase inhibitors from the ethyl acetate and n-butanol fractions of S. angustata leaves. Among these target compounds, thirteen of them are reported as pancreatic lipase inhibitors for the first time. Hyperin, quercetin-3,4'-diglucoside and peltatoside showed stronger binding abilities with pancreatic lipase with ΔG values -9.9, -10.2 and -9.2 kcal/mol while the IC50 values were 0.987 ± 0.079, 0.718 ± 0.054 and 0.916 ± 0.069 mmol/L, respectively. The target compounds quercetin-3,4'-diglucoside and peltatoside were separated with purities higher than 98% using macroporous resin and preparative chromatography.

Predicting the Anti-SARS-CoV-2 Potential of Isoquinoline Alkaloids from Brazilian Siparunaceae Species Using Chemometric Tools

The COVID-19 pandemic has caused over 7 million deaths globally in the past four years. Siparuna spp. (Siparunaceae), which is used in Brazilian folk medicine, is considered a genus with potential antiviral alternatives. This study explored the correlation between phytochemicals in Siparuna leaf extracts (S. ficoides, S. decipiens, S. glycycarpa, S. reginae, and S. cymosa) and their potential against various SARS-CoV-2 targets. In vitro assays examined interactions between the spike protein and the ACE2 receptor, protease activity, and viral replication inhibition in Calu-3 cell models. UHPLC-MS/MS analysis, processed with MZmine and evaluated chemometrically, revealed isoquinoline alkaloids with bulbocapnine, showing promising therapeutic potential. Predictions regarding absorption, distribution, metabolism, excretion, and toxicity were conducted, along with molecular docking and dynamics simulations, to evaluate protein-ligand interaction stability. The results confirmed the antiviral activity of the Siparuna genus against SARS-CoV-2 targets, with 92% of the extracts maintaining over 70% cellular viability at 200 μg·mL-1 and 80% achieving more than 50% viral activity suppression at 50 μg·mL-1. These findings highlight the potential of isoquinoline alkaloids as novel anti-coronavirus agents and support the need for further exploration, isolation, and testing of Siparuna compounds in the fight against COVID-19.

A potential allosteric inhibitor of SARS-CoV-2 main protease (Mpro) identified through metastable state analysis

Anti-COVID19 drugs, such as nirmatrelvir, have been developed targeting the SARS-CoV-2 main protease, Mpro, based on the critical requirement of its proteolytic processing of the viral polyproteins into functional proteins essential for viral replication. However, the emergence of SARS-CoV-2 variants with Mpro mutations has raised the possibility of developing resistance against these drugs, likely due to therapeutic targeting of the Mpro catalytic site. An alternative to these drugs is the development of drugs that target an allosteric site distant from the catalytic site in the protein that may reduce the chance of the emergence of resistant mutants. Here, we combine computational analysis with in vitro assay and report the discovery of a potential allosteric site and an allosteric inhibitor of SARS-CoV-2 Mpro. Specifically, we identified an Mpro metastable state with a deformed catalytic site harboring potential allosteric sites, raising the possibility that stabilization of this metastable state through ligand binding can lead to the inhibition of Mpro activity. We then performed a computational screening of a library (∼4.2 million) of drug-like compounds from the ZINC database and identified several candidate molecules with high predicted binding affinity. MD simulations showed stable binding of the three top-ranking compounds to the putative allosteric sites in the protein. Finally, we tested the three compounds in vitro using a BRET-based Mpro biosensor and found that one of the compounds (ZINC4497834) inhibited the Mpro activity. We envisage that the identification of a potential allosteric inhibitor of Mpro will aid in developing improved anti-COVID-19 therapy.

Myrtucommulones and Related Acylphloroglucinols from Myrtaceae as a Promising Source of Multitarget SARS-CoV-2 Cycle Inhibitors

The LABEXTRACT plant extract bank, featuring diverse members of the Myrtaceae family from Brazilian hot spot regions, provides a promising avenue for bioprospection. Given the pivotal roles of the Spike protein and 3CLpro and PLpro proteases in SARS-CoV-2 infection, this study delves into the correlations between the Myrtaceae species from the Atlantic Forest and these targets, as well as an antiviral activity through both in vitro and in silico analyses. The results uncovered notable inhibitory effects, with Eugenia prasina and E. mosenii standing out, while E. mosenii proved to be multitarget, presenting inhibition values above 72% in the three targets analyzed. All extracts inhibited viral replication in Calu-3 cells (EC50 was lower than 8.3 µg·mL-1). Chemometric analyses, through LC-MS/MS, encompassing prediction models and molecular networking, identified potential active compounds, such as myrtucommulones, described in the literature for their antiviral activity. Docking analyses showed that one undescribed myrtucommulone (m/z 841 [M - H]-) had a higher fitness score when interacting with the targets of this study, including ACE2, Spike, PLpro and 3CLpro of SARS-CoV-2. Also, the study concludes that Myrtaceae extracts, particularly from E. mosenii and E. prasina, exhibit promising inhibitory effects against crucial stages in SARS-CoV-2 infection. Compounds like myrtucommulones emerge as potential anti-SARS-CoV-2 agents, warranting further exploration.

A Novel Approach to Serving Plant-Based Confectionery-The Employment of Spray Drying in the Production of Carboxymethyl Cellulose-Based Delivery Systems Enriched with Teucrium montanum L. Extract

In this study, spray drying was used as a technological solution for the valorization of Teucrium montanum extract into carboxymethyl cellulose-based delivery systems (CMC), individually or in combination with collagen, guar gum, gum arabic, and kappa-carrageenan. The results showed that the process yield and morphological properties were positively influenced by the introduction of CMC binary blends. The employment of CMC resulted in a high encapsulation efficiency (77-96%) for all phenylethanoid glycosides (PGs) analyzed. Due to the low wettability of the microparticles, a relatively gradual in vitro release of the PGs was achieved. Infusion of the filling with hydrophilic T. montanum extract encapsulated in microparticles with high hydrophobic surface area proved to be a practical route for significant confectionery fortification (5-9 mg PGs per dw serving), ensuring prolonged interaction between the food matrix used and the extract under simulated gastrointestinal conditions. Based on sensory evaluation, the introduction of kudzu starch into the jelly matrix has shown a texture-modifying potential.

Physicochemical and Sensory Stability Evaluation of Gummy Candies Fortified with Mountain Germander Extract and Prebiotics

Health-conscious consumers seek convenient ways of incorporating different functional ingredients into their diets. Gummy candies are among the most popular confectionery products but generally regarded as nutritionally empty. A gelatin-sugar matrix, providing a highly appreciated sensory experience of sweetness and chewiness, could be used to deliver various bioactive compounds, especially those carrying an unpleasant taste. This work aimed to formulate gelatin gummies based on the mountain germander extract (MGe) as a source of phenylethanoid glycosides (PhEG). Sucrose and glucose syrup contents were partially or completely substituted with combinations of xylitol, maltitol and prebiotic poly- and oligosaccharides. Chemical, textural and sensory parameters were evaluated after production and 2 months of storage. Formulations containing fructooligosaccharides and xylooligosaccharides maintained a characteristic appearance during storage at all three levels of sugar (high, low and none), whereas inulin-added and plain (i.e., without prebiotic) candies suffered from mold contamination or appearance/textural changes. The color of the candies noticeably changed and appeared darker. The PhEG were shown to be stable during the candies' production (approximately 90%) and generally maintained their contents during storage. Texture parameters, except hardness, exhibited high positive correlations and resembled the commercial product. Sensory-wise, a moderate bitterness intensity with a decreasing tendency, along with the high transparency and preservation of the characteristic shape facilitated high general acceptance. Gummy candies with prebiotics were shown to be a highly suitable matrix for the bitter MGe, delivering up to 40 mg of PhEG and 4.5 g of prebiotics in one serving size. This study provides a reference for implementing herbal extracts and emerging prebiotics (XOS) in functional confectionery.

Teucrium montanum L.-Unrecognized Source of Phenylethanoid Glycosides: Green Extraction Approach and Elucidation of Phenolic Compounds via NMR and UHPLC-HR MS/MS

Health-oriented preferences, a demand for innovative food concepts, and technological advances have greatly influenced changes in the food industry and led to remarkable development of the functional food market. Incorporating herbal extracts as a rich source of bioactive compounds (BC) could be an effective solution to meet the high demand of consumers in terms of expanding the high-quality range of functional foods. The aim of this study is the valorization of the bioactive potential of T. montanum L., an understudied Mediterranean plant species, and the in-depth elucidation of a polyphenolic profile with a UHPLC-HR MS/MS and NMR analysis. The total phenolic content (TPC) and antioxidant capacity (AC) were determined on heat-assisted (HAE), microwave-assisted (MAE) and subcritical water (SWE) extracts. In terms of antioxidant capacity, SWE extracts showed the most notable potential (ABTS: 0.402-0.547 mmol eq Trolox g-1 dw, DPPH: 0.336-0.427 mmol eq Trolox g-1 dw). 12 phenolic compounds were identified in the samples of T. montanum from six microlocations in Croatia, including nine phenylethanoid glycosides (PGs) with total yields of 30.36-68.06 mg g-1 dw and 25.88-58.88 mg g-1 dw in HAE and MAE extracts, respectively. Echinacoside, teupolioside, stachysoside A, and poliumoside were the most abundant compounds HAE and MAE extracts, making T. montanum an emerging source of PGs.