Phytobiological Investigation and In Silico Docking Study of Secondary Metabolites from Saussurea lappa Roots

Abstract Chromatographic exploration of methanol extract derived from Saussurea lappa roots yielded four sesquiterpene lactones, santamarin ( 1 ), dehydrocostuslactone ( 2 ), costunolide ( 3 ) and zaluzanin C ( 4 ) along with the well‐known triterpene, β ‐sitosterol ( 5 ). Chemical structures were determined based on extensive 1D/2D NMR analyses. In antiviral assay, compounds 1–5 showed % antiviral activity ranging from 2.18±3.1 to 53.7±10.05 % and from 15.39±4.83 to 92.91±2.47 % when tested against hepatitis A virus (HAV) and Herpes simplex virus type 1 (HSV‐1), respectively. Molecular docking simulation studies against (HSV‐1) DNA polymerase and (HAV) 3 C proteinase enzymes showed similar binding interactions as for acyclovir. Compounds ( 1 and 3–5 ) showed moderate to potent antibacterial activity against Bacillus subtilis ATCC 6633 (MIC values between 7.9 and 31.25 μ g /ml) whereas, dehydrocostuslactone ( 2 ) and costunolide ( 3 ) exhibited comparable antibacterial activities against Pseudomonas aeruginosa ATCC 90274 (MIC values=125 μ g /ml) compared to gentamicin as a positive control. In cytotoxicity assay against human colorectal carcinoma (HCT‐116) and human epithelioid cervical carcinoma (HeLa), compounds 1 and 4 exhibited weak to moderate activities. Compound 1 showed IC 50 values of 46.05 μg/ml (185.44 μ M) and 59.38 μg/ml (239.1153 μ M) whereas compound 4 showed IC 50 values of 36.08 μg/ml (146.48 μ M) and 46.59 μg/ml (189.175 μ M), respectively.