There are different specifications and natural sources for maslinic acid.
Generally speaking, there are three main sources:
1.Olive (Olea europaea) High concentration of maslinic acid is found in the waxy skin of olives, reaching as high as 80%.
2.Crataegus pinnatifida (aka Chinese hawthorn, or Hawthorn berry)
3.Eriobotrya japonica (Thunb.) Lindl (loquat leaves)

Eriobotrya japonica is unique to China, and you'll find all suppliers who supply maslinic acid from loquats are from China.
According to Wikipedia, Maslinic acid is a byproduct of oil extraction from dry olive-pomace oil. It seems that olive is the main source of mass production of maslinic acid powder. However, it is probably not. It's difficult to isolate maslinic acid from olive leaves or oils. And the cost is also quite high.
In reality, the loquat leaf extract is the best source.
Loquat source is new to the market; Loquat is abundant; the production technology is easy to operate.