A Fluoro Derivative of Embelin, as Potent B-RAF Inhibitor in Melanoma

Abstract

Background: Melanoma is one of the common forms of skin cancer and B-RAF is a mutated protein found in most Melanomas. The important function of B-RAF is normal cell growth and survival. Most of known B-RAF mutations are V600E mutations. Vemurafenib is the currently used fluorine based drug used for V600E mutations but this drug has side effects, so in this scenario, more potent drugs with less side effects are required. Objective: This study aims to develop a more effective lead compound as B-RAF inhibitor from a hydroxyquinone, by structural modification of embelin, a naturally occurring hydroxybenzoquinone, which has got a potency of detoxifying blood, hence useful in wide range of skin diseases. Thus a fluorine substituted semisynthetic derivative of embelin, 5-(3-chloro-4-trifluoromethoxy phenyl amino)-2- hydroxy-3-undecyl- [1, 4] benzoquinone to fight against skin cancer was prepared. Method: Fluoro derivative of embelin was synthesized by the direct condensation of embelin with 3-chloro-4-trifluoromethoxy aniline. The structure of the product was characterized using various spectral data, obtained from IR, 1H NMR, 19F NMR, 13C NMR and Mass spectrum. Various in vitro studies like Antiproliferative study in A375 Cell Lines, (B-RAF Elisa), Western Blotting analysis, Gene Expression study by Reverse Transcriptase PCR, Caspase assay, Flow Cytometry analysis, Clonogenic assay and Transwell Migration assay were carried out to find its biological activity. Results: A semisynthetic derivative of embelin 5-(3-chloro-4-trifluoromethoxy phenyl amino)-2-hydroxy-3-undecyl- [1, 4] benzoquinone (EOCF) was prepared and the structure of the derivative was confirmed by spectral analysis. The MTT assay proves that the fluoro derivative of embelin exhibited better anticancer activity in Melanoma cell lines than the parent compound, embelin. Western blot analysis showed that B-RAF expression level was reduced by the addition of derivative than the parent compound embelin. The Caspase ELISA analysis indicated that the derivative was found to be a good apoptotic marker and from the flow cytometry analysis, it was observed that the cell arrest occurs at G0/G1 phase. Its antimetastatic activity determined using Clonogenic assay indicated that the derivative, EOCF inhibits the metastatic effects in melanoma cell lines. Migratory potential of Melanoma cells were significantly reduced in presence of EOCF when Transwell migration assay was conducted. Conclusion: This work established that the potency of the synthesized compound was more than the parent compound, embelin when it was structurally modified with 3-chloro-4-trifluoromethoxy aniline and that the derivative can be used as a lead molecule for further drug discovery.

Synthesis and characterisation of copper acetate mediated oxidative coupled product of naturally occurring hydroxy benzoquinone, embelin and its in vitro and in vivo cytotoxic studies in Dalton Lymphoma ascites tumour cells

“…The results were also compared with the standard drug PLX. The study had revealed comparable cell viability for both these compounds [Arunkumar et al 2021]. In the instant investigation, the EOCF synthesized by the copper acetate mediated route was subjected to in vivo studies in albino mice.…”

Synthesis of Quinoline and Dihydroquinoline Embelin Derivatives as Cardioprotective Agents

“…Embelin ( 1 ) is a natural benzoquinone isolated from Oxalis erythrorhiza . This compound and some derivatives have shown activity against multiple targets such as CK2, , XIAP, α-glucosidase, B-RAF, or PKC . It acts as an inhibitor of neuroserpin polymerization and as a GPR84 agonist, modulates Akt/β-catenin and p38 MAPK, and blocks the NF-κβ signaling pathway. , This plethora of protein targets and pathway modulations have attracted the interest of medicinal chemists. − …”