The isolation and identification of a hydrojuglone glycoside occurring in the walnut.

In a preliminary note (Daglish & Wokes, 1948) it was shown that the 'apparent vitamin C' of the walnut (Juglan8 regia) (Wokes, Organ, Duncan & Jacoby, 1943) was probably a hydrojuglone derivative. The evidence for this was based upon the findings that solutions of the substance separated by chromatography showed an ultraviolet absorption curve similar to those of reduced acetoxyjuglone and ahydrojuglone, and on hydrolysis yielded juglone. Thiswork hasnowbeen extended, and it appears that this substance is glycosidal in nature with the sugar moiety attached to the 5-hydroxyl of 1:4:5-trihydroxynaphthalene. This paper describes the work leading to its isolation and identification.