Molecular docking of bioactive compounds extracted and purified from selected medicinal plant species against covid-19 proteins and in vitro evaluation

Abstract

AbstractBioactive compounds are secondary metabolites of plants. They offer diverse pharmacological properties. Peganum harmala is reported to have pharmaceutical effects like insecticidal, antitumor, curing malaria, anti-spasmodic, vasorelaxant, antihistaminic effect. Rosa brunonii has medicinal importance in its flower and fruits effective against different diseases and juice of leaf is reported to be applied externally to cure wounds and cuts. Dryopteris ramosa aqueous leaf extract is used to treat stomach ulcers and stomachaches. Each of these three medicinal plants have been indicated to have anticancer, antiviral, antioxidant, cytotoxic and antifungal effects but efficacy of their bioactive compounds remained unexplored. Study was aimed to explore In-vitro and In-silico anticancer, antiviral, antioxidant, cytotoxic and antifungal effects of bioactive compounds of above three medicinal plants. DPPH and ABTS assay were applied for assessment of antioxidant properties of compounds. Antibacterial properties of compounds were checked by agar well diffusion method. Brine shrimp lethality assay was performed to check cytotoxic effect of compounds. Molecular docking was conducted to investigate the binding efficacy between isolated compounds and targeted proteins. The compound isomangiferrin and tiliroside presented strong antioxidant potential 78.32% (± 0.213) and 77.77% (± 0.211) respectively in DPPH assay while harmaline showed 80.71% (± 0.072) at 200 µg/mL in ABTS assay. The compound harmine, harmaline and PH-HM 17 exhibited highest zone of inhibition 22 mm, 23 mm, 22 mm respectively against Xanthomonas while Irriflophenone-3-C-β- D-glucopyranoside showed maximum zone of inhibition 34 mm against E. coli. The compound isomangiferrin and vasicine contained strong antibacterial activity 32 mm and 22 mm respectively against S. aureus. The compound mangiferrin, astragalin, tiliroside, quercitin-3-O-rhamnoside showed maximum inhibitory zone 32 mm, 26 mm, 24 mm and 22 mm respectively against Klebsiella pneumoniae. Highest cytotoxic effect was observed by compound tiliroside i.e. 95% with LD50 value 73.59 µg/mL. The compound tiliroside showed the best binding mode of interaction to all targeted proteins presenting maximum hydrophobic interactions and hydrogen bonds. The binding affinity of tiliroside was − 17.9, − 14.9, − 14.6, − 13.8, − 12.8 against different proteins 6VAR, 5C5S, IEA3, 2XV7 and 6LUS respectively. Bioactive compounds are significant natural antioxidants, which could help to prevent the progression of various diseases caused by free radicals. Based on molecular docking we have concluded that phytochemicals can have better anticancer and antiviral potential.