I suppose it is possible they had some new world plants. But an argument against it might be not what we think they had (in them), but what they DIDN'T.
Potatoes. Tomatoes. A half dozen gourd types.
If the Egyptians were wandering around South America picking coca leaves, seems alot more than that would find it's way back to Egypt.
Tomatoes, tomatillos, and potatoes are New World. But other plants in the Solanacae family existed in the Old World. Henbane, for example. And Hyoscyamine, its alkaloid, used to be used in Contac cold capsules as the sulfate.
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Carboxylate Hyoscyamine, and it's Party Time.