This is believed to be because it contains high levels of Methylglyoxal which is a powerful antiseptic, and a substance called bee defensin - 1. (sugar-and-sweetener-guide.com)
The compounds — called alpha defensins — are part of the body's first line of defence against infection. (sciencedaily.com)
There is a group of protective agents called defensins to fight against invading bacteria, viruses, and fungi. (tracyhuang.me)