The end of the trans-Atlantic slave trade resulted in

a decrease in money going to African kingdoms

Explanation:

The end of the trans-Atlantic slave trade was a major economic blow for the African kingdoms. The African kingdoms made big portion of their profit from selling slaves that they have captured from the other tribes to the Europeans. Once the slavery was abolished, the money toward the African kingdoms stopped as well, which led to their weakening and eventually collapse, later being used by the Europeans to overtake them.

trade regulation is a field of law, often bracketed with antitrust (as in the phrase “antitrust and trade regulation law”), including government regulation of unfair methods of competition and unfair or deceptive business acts or practices. antitrust law is often considered a subset of trade regulation law. franchise and distribution law, consumer protection law, and advertising law are sometimes considered parts of trade regulation law.

in general the theory of economics says that the more open to trade a country is the better   the result for the same country and the whole economies.

in real life countries impose taxes, quotas, etc which is not so good for the economies.

this kind of commercial war between the usa and china is slowing down the growth of the whole world so we can say that it is a draw back of trade regulations. and the free trade agreements are benefits of trade regulations.