Effects of Phlorizin Isolated from Apple Leaves and Its Aglycone Phloretin on Adrenal Cortisol Production

Seven galloyl, caffeoyl and (S)-hexahydroxydiphenoyl (HHDP) esters of dihydrochalcone glucosides were isolated from Balanophora tobiracola; based on spectroscopic and chemical evidence, their structures were determined to be 6″-O-galloyl-, 3″,4″-di-O-galloyl-, 4″,6″-di-O-galloyl-, 4″,6″-O-(S)-HHDP-, 3″-O-galloyl-4″,6″-O-(S)-HHDP-, 3″-O-caffeoyl-4″,6″-O-(S)-HHDP-3-hydroxyphloretin 4′-O-β-d-glucosides and 3″-O-galloyl-4″,6″-O-(S)-HHDP-phloretin 4′-O-β-d-glucoside, respectively. By contrast, these compounds were not found in the taxonomically related B. japonica. The 3″-galloyl-4″,6″-HHDP esters of the dihydrochalcone glucosides showed strong inhibitory activities against α-glucosidase. Four known compounds were also isolated namely, (±)-eriodictyol 7-O-β-d-glucoside, 1-O-caffeoyl-3-O-galloyl-β-d-glucose, phloretin 4′-O-β-d-glucoside, and 3-hydroxyphloretin 4′-O-β-d-glucoside.