quotBioactivity guided Isolation Molecular Ligand Target Insight And in vitro Antiviral Evaluation of Stobilanthes ciliatus Nees Bremekquot

Abstract

Herbal medicines and purified bioactive molecules from nature continue to be a significant source of novel antiviral drug discovery and development. Viruses are usually evolved in devious processes to invade the host immune responses. Despite the considerable success achieved in immunization and antiviral drug development, many viruses lack effective treatment strategies. The primary antiviral screening of the petroleum ether, chloroform, ethyl acetate and ethanolic extracts of the stem, root and leaves of the plant against 10TCID50 and 100TCID50 viral doses of both HSV-1 and HSV-2 by CPE assay indicated that chloroform extract of the leaves (NCL-CH) possess the maximum activity against both viruses. The extract was further taken up for isolation of active constituents. Bioactivity guided isolation based on CPE assay and MTT assay yielded five fractions and among these, Fr.3 and Fr.9 were found to be highly active. Purification of the Fr.9 yielded a novel quinazoline type alkaloid (NCL-1) and fr.3 yielded a triterpenoid molecule betulin (NCL-2). NCL-1 exhibited significant viral inhibition with IC50 value11.97and#956;g/ml, SI 4.47 against HSV-1 and 14.69 and#956;g/ml, SI 3.64 against HSV-2, respectively. Betulin is known to be an anti-HSV compound. It was found to be more active than NCL-1. NCL-1 exhibited maximum activity during viral replication stage (90% HSV 1 and 86% HSV 2) on addition of the at different viral infection stages like standard acyclovir. Betulin exhibited maximum activity at pretreatment of cells. In silico docking of NCL-1 with the selected targets from viral replication stage showed highest interaction with HSV DNA polymerase (IDML). Compounds did not show any kind of mutagenicity in Ame s reverse mutation.The present study confirmed the antiviral potential the plant Strobilanthes ciliates Nees (Bremek.) and yielded two anti-HSV molecules. A new quinazolin type alkaloid (NCL-1) that shows antiviral activity, both in vitro and in silico, is being reported for the first time. newline