I am visiting some relatives in Malaysia. They introduced me to this plant and talk about the health benefits of consuming this plant. I am trying to find out more about this plant, but they could only provide the name in the local dialect.
I asked further and confirmed that this plant has a rather roundish white flower. It is currently not blooming so I don't have photos, but the flower is described as small and round, about the size of the first phalanx of the thumb.
The locals call it "Cheng Ma Jin" or some others call it "Tit Ma Cheng". It might be due to different dialects or just pronunciation since they are mostly elderly.