I found Dr. Kinghorn’s talk very interesting. I’m not sure why, but it’s crazy for me to sit and think about how there are plants out there that could treat/cure diseases, many of which we haven’t discovered yet. It seems pretty extremely lucky that some of the cures for different illnesses or treatments for symptoms have been discovered from basically guessing which plants or parts of plants to test. Maybe there is a more “scientific” approach to this, but it seems like mostly a “guess and check” sort of process. The process of trying to test and approve a new drug seems exhausting as well. I’m not sure I would have the patience for this particular field of research!
It is worthwhile to consider that plants make compounds that specifically affect animal metabolism (mostly insects) for their own protection. Medicines are often toxic compounds that are medicines at a particular (non-toxic) dose. In this way, it may be less luck, but you are right that there are so many compounds and the process of drug discovery seems tedious. It makes sense that we often start with traditional medicines because they have at least some degree of testing already built in.