Antiviral Activity of Curcuminoids Derived from Deverra tortuosa Plant

Curcuminoids are natural products with widespread biological activity mostly extracted from Curcuma longa and its family. In the current study, we report the first time to isolate curcuminoids from another phyto source. Three compounds (curcumin, desmethoxycurcumin (DMC), and bisdemethoxycurcumin (BDMC)) were isolated from the plant Deverra tortuosa using methanolic extract, which was then fractionated and separated by puriFlash. The purity of compounds was monitored by thin-layer chromatography and confirmed by high-performance liquid chromatography. The mass spectrometry identified the isolated compound by their electrospray ionisation. Molecular docking then demonstrated that curcumin and BDMC bind at the same cavity (187 Å) on SARS-CoV-2 M^pro protein indicating similarities while DMC binds to a cavity with a larger size (372 Å). Among the three curcuminoids, BDMC was shown to give the highest binding energy (−7.5 kcal/mol) followed by curcumin (−7.4 kcal/mol) and DMC (−7.3 kcal/mol). Calculating the half-maximal cytotoxic concentration and inhibitory median concentration of both DMC and BDMC showed low-to-moderate antiviral activity against SARS-CoV-2.