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
Glue stick Glue stick Glue sticks are solid adhesives in twist or push-up tubes. The user can apply glue by holding the open tube, and keeping their fingers clean. Most glue sticks are designed to glue paper and card together, and are not as strong as some liquid based variants. They can be used for craft and design, office use and at school. There are now permanent, washable, acid-free, non-toxic, solvent free, and dyed (e.g. to see where the glue is being applied easier) varieties. These are most commonly used today. In 1969 the German company Henkel invented the glue stick after