The discovery and development of novel
antiviral drugs from natural sources is continuously increasing due to limitations of currently available drugs such as toxic
side effects, drug residue risk factors, high costs, and poor therapeutic strategies. Also, there are very few known
antiviral drugs that are effective against only specific viruses. Hence, the present study is intended to isolate and characterize potent
antiviral compounds from the methanolic root extract of Sophora interrupta Bedd. against avian paramyxovirus, Newcastle disease virus (NDV) and to distinguish the molecular basis of
antiviral compounds. The two isolated
flavonoids,
maackiain (SR-1) and
echinoisoflavanone (SR-2) exhibited the best
antiviral activities against NDV
infection in chicken embryo fibroblast cell lines compared to the standard
antiviral drug,
Ribavirin. Further, the in vitro studies and quantitative PCR analysis suggests that these
flavonoids inhibit the viral entry, replication, and transcription, which may be beneficial as a promising strategy for the treatment of
viral infections. Besides, the molecular docking studies of SR-1 and SR-2 exhibited high binding affinities of -7.6 and -8.0 kcal mol-1, respectively, and marked interactions with the NDV
surface glycoprotein,
hemagglutinin neuraminidase (HN). Also, the in silico toxicity properties as well pharmacokinetic studies of isolates revealed them as pharmacologically potent
antiviral compounds.