New Products Generated from the Transformations of Ferulic Acid Dilactone

Natural defense against multi-drug resistant Pseudomonas aeruginosa: Cassia occidentalis L. in vitro and in silico antibacterial activity

Cassia occidentalis L. is widely used in indigenous and traditional medicine, but its impact on multi-drug resistant (MDR) bacterial infections mostly remains unknown. Therefore, this study aimed to evaluate the in vitro antibacterial efficiency of methanol and ethyl acetate extracts of C. occidentalis L. leaves (MECOL and EAECOL) against multi-drug resistant Pseudomonas aeruginosa and to identify potential antibacterial agents through computational studies targeting the LasR protein. Initially, 82 compounds were identified using GC-MS analysis, and the functional groups were determined through FT-IR analysis. Both extracts of the plant exhibited dose-dependent antibacterial activity, with MICs of 104.16 ± 36.08 μg mL-1 for MECOL and 83.33 ± 36.08 μg mL-1 for EAECOL, and an MBC of 125 μg mL-1. Among the 82 compounds, 12 potential compounds were identified based on binding scores using molecular docking with the LasR protein and MM-GBSA analysis. Furthermore, screening for ADME properties, including physicochemical features, water solubility, lipophilicity, RO5 compliance, and toxicity, identified the top three compounds: methyl dihydrojasmonate, methyl benzoate, and 4a-methyl-4,4a,5,6,7,8-hexahydro-2(3H)-naphthalenone, which also demonstrated binding affinity with the active site residues of the LpxC protein of the bacteria. Additionally, molecular dynamics (MD) simulations confirmed the binding reliability of these three phytochemicals to LasR's active pocket, comparable to the protein native inhibitory ligands (C12-HSL). The study offers scientific support for the traditional use of C. occidentalis in treating bacterial infections, highlighting the potential of the three compounds as leads for developing LasR inhibitors to combat multi-drug resistant P. aeruginosa.

Evaluation of Senna tora (L.) Roxb. leaves as source of bioactive molecules with antioxidant, anti-inflammatory and antibacterial potential

Senna tora (L.) Roxb. is an ethno-medicinal herb used by rural and tribal people of the Satpura region of Madhya Pradesh in India and the Phatthalung Province of Thailand for treating rheumatism, bronchitis, ringworm, itches, leprosy, dyspepsia, liver disorders and heart disorders. It is also used in Chinese and Ayurvedic medicine. This study was conducted to investigate the potential of Senna tora (L.) Roxb. as a source of drug candidates against oxidants, inflammation, and bacterial infection. Preliminary phytochemical screening (PPS) and GC-MS were performed to identify the phytochemicals in the ethyl acetate extract of Senna tora (L.) Roxb. leaves (EAESTL). The in vitro antioxidant activity was assessed by 2,2-diphenyl-1-picrylhydrazyl (DPPH)- and H₂O₂-scavenging tests; the in vitro anti-inflammatory activity was determined by bovine serum albumin (BSA) denaturation and red blood cell (RBC) hemolysis inhibition; and the antibacterial activity was evaluated by agar-well diffusion methods. Cytotoxicity was estimated by Artemia salina larvae lethality, while acute toxicity was evaluated by oral delivery of the extract to mice. In silico antioxidant, anti-inflammatory, and antibacterial activities were predicted by the Prediction of Activity Spectra for Substances (PASS) program. The pharmacokinetics related to ADME and toxicity tests were determined by the admetSAR2 and ADMETlab2 web servers, and drug-able properties were assessed by the SwissADME server. GC-MS detected fifty-nine phytochemicals that support the types of compounds (phenols, flavonoids, tannins, terpenoids, saponins, steroids, alkaloids, glycosides and reducing sugar) identified by phytochemical screening. EAESTL exhibited dose-dependent antioxidant, anti-inflammatory, and antibacterial activities without any adverse effects or fluctuations in body weight. The PASS program predicted that the identified phytochemicals have antioxidant, anti-inflammatory and antibacterial activities. Among 51 phytochemicals, 16 showed good ADME, and 8 fulfilled drug-able properties without toxicity. Altogether, four phytochemicals, viz., benzyl alcohol, 3-(hydroxy-phenyl-methyl)-2,3-dimethyl-octan-4-one, phenylethyl alcohol and 2,6,6-trimethylbicyclo [3.1.1] heptane-3-ol, showed good pharmacokinetics and drug-able properties without toxicity, along with antioxidant, anti-inflammatory, and antibacterial activities. The obtained results suggest that Senna tora (L.) Roxb. leaves contain bioactive phytochemicals that have the potential to fight against oxidants, inflammation, and bacterial infection as potential drug candidates.

High-throughput platform for yeast morphological profiling predicts the targets of bioactive compounds

Morphological profiling is an omics-based approach for predicting intracellular targets of chemical compounds in which the dose-dependent morphological changes induced by the compound are systematically compared to the morphological changes in gene-deleted cells. In this study, we developed a reliable high-throughput (HT) platform for yeast morphological profiling using drug-hypersensitive strains to minimize compound use, HT microscopy to speed up data generation and analysis, and a generalized linear model to predict targets with high reliability. We first conducted a proof-of-concept study using six compounds with known targets: bortezomib, hydroxyurea, methyl methanesulfonate, benomyl, tunicamycin, and echinocandin B. Then we applied our platform to predict the mechanism of action of a novel diferulate-derived compound, poacidiene. Morphological profiling of poacidiene implied that it affects the DNA damage response, which genetic analysis confirmed. Furthermore, we found that poacidiene inhibits the growth of phytopathogenic fungi, implying applications as an effective antifungal agent. Thus, our platform is a new whole-cell target prediction tool for drug discovery.

GC-MS analysis of phytoconstituents from Ruellia prostrata and Senna tora and identification of potential anti-viral activity against SARS-CoV-2

SARS-CoV-2 is an etiologic agent responsible for the coronavirus disease 2019 (COVID-19) pandemic. The virus has rapidly extended globally and taken millions of lives due to the unavailability of therapeutics candidates against the virus. Till now, no specific drug candidates have been developed that can prevent or treat infections caused by the pathogen. The main protease (M^pro) of the SARS-CoV-2 plays a pivotal role in mediating viral replication and mechanistically inhibition of the protein can hinder the replication and infection process of the virus. Therefore, the study aimed to identify the natural bioactive compounds against the virus that can block the activity of the M^pro and subsequently block viral infections. Initially, a total of 96 phytochemicals from Ruellia prostrata Poir. and Senna tora (L.) Roxb. plants were identified through the gas chromatography-mass spectrometry (GC-MS) analytical method. Subsequently, the compounds were screened through molecular docking, absorption, distribution, metabolism, excretion (ADME), toxicity (T), and molecular dynamics (MD) simulation approach. The molecular docking method initially identified four molecules having a PubChem CID: 70825, CID: 25247358, CID: 54685836 and, CID: 1983 with a binding affinity ranging between −6.067 to −6.53 kcal mol⁻¹ to the active site of the target protein. All the selected compounds exhibit good pharmacokinetics and toxicity properties. Finally, the four compounds were further evaluated based on the MD simulation methods that confirmed the binding stability of the compounds to the targeted protein. The computational approaches identified the best four compounds CID: 70825, CID: 25247358, CID: 54685836 and, CID: 1983 that can be developed as a treatment option of SARS-CoV-2 disease-related complications. Although, experimental validation is suggested for further evaluation of the work.

Protease (M^pro) of SARS-CoV-2 has been identified as being able to hinder the replication process of the virus. Using GC-MS analytical methods, phytochemicals were identified from different medicinal plants that resulted in inhibitory activity of the molecules against M^pro.

Transformation of low molecular compounds and soil humic acid by two domain laccase of Streptomyces puniceus in the presence of ferulic and caffeic acids

The two-domain bacterial laccases oxidize substrates at alkaline pH. The role of natural phenolic compounds in the oxidation of substrates by the enzyme is poorly understood. We have studied the role of ferulic and caffeic acids in the transformation of low molecular weight substrates and of soil humic acid (HA) by two-domain laccase of Streptomyces puniceus (SpSL, previously undescribed). A gene encoding a two-domain laccase was cloned from S. puniceus and over-expressed in Escherichia coli. The recombinant protein was purified by affinity chromatography to an electrophoretically homogeneous state. The enzyme showed high thermal stability, alkaline pH optimum for the oxidation of phenolic substrates and an acidic pH optimum for the oxidation of K4[Fe(CN)6] (potassium ferrocyanide) and ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt). Phenolic compounds were oxidized with lower efficiency than K4[Fe(CN)6] and ABTS. The SpSL did not oxidize 3.4-dimethoxybenzoic alcohol and p-hydroxybenzoic acid neither in the absence of phenolic acids nor in their presence. The enzyme polymerized HA-the amount of its high molecular weight fraction (>80 kDa) increased at the expense of low MW fraction (10 kDa). The addition of phenolic acids as potential mediators did not cause the destruction of HA by SpSL. In the absence of the HA, the enzyme polymerized caffeic and ferulic acids to macromolecular fractions (>80 kDa and 10-12 kDa). The interaction of SpSL with HA in the presence of phenolic acids caused an increase in the amount of HA high MW fraction and a two-fold increase in the molecular weight of its low MW fraction (from 10 to 20 kDa), suggesting a cross-coupling reaction. Infrared and solution-state 1H-NMR spectroscopy revealed an increase in the aromaticity of HA after its interaction with phenolic acids. The results of the study expand our knowledge on the transformation of natural substrates by two-domain bacterial laccases and indicate a potentially important role of the enzyme in the formation of soil organic matter (SOM) at alkaline pH values.