(2R,3R)-2-(2,4-dihydroxyphenyl)-3,5,7-trihydroxy-6-(3-methylbut-2-en-1-yl)-8-[(2R)-5-methyl-2-(prop-1-en-2-yl)hex-4-en-1-yl]-2,3-dihydro-4H-chromen-4-one