Propolis recently been isolated from red propolis, and prenylated acids such as 4-hydroxy-3,5-diprenyl cinnamic acid have been documented. An analysis of propolis from Henan, China found sinapinic acid, isoferulic acid, caffeic acid, and chrysin, with the first three compounds demonstrating antibacterial properties. Also, Brazilian red propolis, largely derived from "Dalbergia ecastaphyllum" plant resin, has high relative percentages of the isoflavonoids 3-hydroxy-8,9-dimethoxypterocarpan and medicarpin. Other flavonoids commonly present include galangin and pinocembrin. Caffeic acid phenethyl ester (CAPE) is also a component of some varieties of propolis from New Zealand. Occasionally, worker bees will even gather various caulking compounds of human manufacture, when
Hoof glue fine woodworking projects where the joints must be extremely fine if not invisible. The general process is to take the hooves of ungulates and break them into small chunks and then boil them in water until all the hoof material has been liquefied. An acid is then added to create a thick gel. The resultant product is then cooled and allowed to harden. Once melted, it is necessary to heat the glue substance until it is the required consistency – thin hoof glue can be used to stiffen fabrics; thicker glue is used in cabinetry. The storable form of hoof