A new flavonol derivative and other compounds from the leaves of Bauhinia thonningii Schum with activity against multidrug-resistant bacteria

Computational biology of antibody epitope, tunnels and pores analysis of protein glutathione S-transferase P, and quantum mechanics

Different tissues of various plants contain allelochemicals such as phenolics, flavonoids, etc., which exhibit antioxidants and protect the plants from harmful infections. The widespread group of plant allelochemicals in the ecosystem is phenolic compounds. They are substances composed of an aromatic hydrocarbon group and a hydroxyl group. The 3-Hydroxyflavone skeleton of flavonol has a phenolic and a hydroxyl substitution. A comparison of experimental and calculated data of FT-IR and Raman was studied for the vibrational assessment of these allelochemicals. PES scan and molecular geometry analysis are done for the conformation of the 3-Hydroxyflavone ligand. 3-Hydroxyflavone is docked with the three proteins of Homo sapiens such as Prothrombin with 622 amino acids synthesized in the liver, human neutrophils found within intracellular granules with 467 amino acids, Glutathione S-transferase P is produced from exogenous xenobiotics with 210 amino acids. The active site residues by using the Prothrombin (1A2C), Neutrophil collagenase (1A86), Glutathione S-transferase P(18 GS) protein with ligand 3-Hydroxyflavone, fair binding affinity was found for the Glutathione S-transferase P (18 GS). The MOLE online server web interface's ability to see and analyze tunnels and pores allows for simple, online interaction with bio-macromolecule investigation. The automatic transmembrane channel calculation on the MOLE web generates the quickest list of ligands for transport analysis and tunnel identification. Pore-forming proteins (PFPs) are recognized as crucial agents in immunity and infection. They target membranes by opening channels through them. ElliPro is thought to be a potentially effective method for identifying antibody epitopes in protein antigens. Molecular dynamics result the general time-dependent structural deviation/degree of similarity among the structures that the trajectory records. The epitope technique sought to examine the effectiveness of its web tool on linear and discontinuous epitopes known from the structures of antibodies of 18 GS with 3-Hydroxyflavone complexes and find effective scores.

Cytotoxicity, acute and sub-chronic toxicities of the leaves of Bauhinia thonningii (Schumach.) Milne-Redh. (Caesalpiniaceae)

BACKGROUND

Bauhinia thonningii is a plant traditionally used against many human diseases such as gastric ulcers, fever, inflammations, coughs, dysentery, diarrhea, and malaria. In the present investigation, the cytotoxicity of methanol extract of Bauhinia thonningii leaves (BTL), fractions and the isolated phytoconstituents was determined in a panel of 9 human cancer cell lines including drug sensitive and multidrug-resistant (MDR) phenotypes. The acute and sub-chronic oral toxicity of BTL was investigated as well.

METHODS

Compounds were isolated using chromatographic techniques while their chemical structures were determined using spectroscopic methods. The resazurin reduction assay (RRA) was used to evaluate the cytotoxicity of samples, propidium iodide (PI) for apoptosis, 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolylcarbocyanine iodide (JC-1) staining for mitochondrial membrane potential (MMP) analysis, 2´,7´-dichlorodihydrofluoresceine diacetate (H2DCFH-DA) staining for the quantification of reactive oxygen species (ROS), whereas Caspase Glo assays were combined by means of flow cytometry. Furthermore, the toxicological investigations were performed as recommended by the Organization for Economic Cooperation and Development (OECD).

RESULTS

The botanicals as well as 6-C-methylquercetin-3,7-dimethyl ether (2), quercetin-3-O-L-rhamnopyranoside (5), quercetin-3-O-β-glucopyranoside (6), 6,8-C-dimethylkaempferol 3,7-dimethyl ether (7), and 6,8-C-dimethylkaempferol-3-methyl ether (8) had promising cytotoxic effects in the 9 tested cancer cell lines. The IC50 values below 20 µg/mL (botanicals) or 10 µM (compounds) on at least 1/9 tested cancer cell lines were considered. The best cytotoxic effects with IC50 values below 5 µM were achieved with compounds 7 against CEM/ADR5000 leukemia cells (2.86 µM) and MDA-MB-231-pcDNA breast adenocarcinoma cells (1.93 µM) as well as 8 against CCRF-CEM leukemia cells (3.03 µM), CEM/ADR5000 cells (2.42 µM), MDA-MB-231-pcDNA (2.34 µM), and HCT116 p53-/- cells (3.41 µM). BTL and compound 8 induced apoptotic cell death in CCRF-CEM cells through caspase activation, alteration of MMP, and increased ROS production. BTL did not cause any adverse effects in rats after a single administration at 5000 mg/kg or a repeated dose of 250 mg/kg body weight (b. w.).

CONCLUSION

Bauhinia thonningii and its constituents are sources of cytotoxic drugs that deserve more in-depth studies to develop novel antiproliferative phytomedicine to fight cancer including resistant phenotypes.