What would be right (to be ideal or Potential) concentration (ug/ml) of a plant crude drug extract at 50% inhibition (IC50) values against MCF-7 human breast cancer cell lines?

I have red an article there

"The American National cancer institute guidelines set the limit of activity for crude drug extracts at 50% inhibition (IC50) of proliferation of less than 30ug/ml, after exposure time of 72 hours."

But My plant extracts given IC50 (ug/ml) values above 160ug/ml after exposure time of 48 hours.

Are these results good? Can go for publication with these results?

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