Rejected publication
I cannot comment on your specific manuscript since I obviously cannot read it but in general the question is whether a study does add an interesting novelty.
The problem with pure in silico studies is that there is essentially no confirmation towards the in vivo relevance. Drug companies simulate and also test many thousands of compounds in a high-throughput fashion on a daily basis so it is often questionable to what extend individual pure in silico studies without in vivo confirmation do actually add to the bigger picture.
That might be the reason your work was rejected but as said this is a rather general comment and I can neither judge content nor quality of your work so please do not feel offended and read it with a grain of salt.