The preferred method would be to first export the media using the same program that created it: in this case it's PowerPoint. You can choose to display the individual slides then export each piece of media for use in your NLE. Sometimes not everything would export properly using earlier Mac versions of PowerPoint but more recent versions would probably work better. Exporting using a PC version is the best then transferr the results back to your Mac. You can try importing the PP show into Keynote and export from that but often things won't export properly because of the "Lost in Translation" issues. But at least Keynote will advise you when that happens. I haven't tried the latest versions of Keynote because I haven't needed to do this job for a couple of years. Using the Mac version of Sorensen Squeeze would also work the best to do the transcoding as well.
Powerpoint counts on the target machine having all the same fonts as the originating machine. When the playing machine lacks an element, it tries to substitute something else "like" it, and this can goof up text files.