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DOI: 10.1055/s-0034-1382548
Antifungal isopimaradiene diterpenoids from Sagittaria latifoli
Antifungal screening of our small-molecule natural product libraries showed that a column fraction derived from the organic extract of Sagittaria latifolia (Alismataceae) was active against the clinically important opportunistic pathogen Cryptococcus neoformans. Subsequent bioassay- and LC-MS-guided fractionation of this plant extract resulted in the identification of two new isopimaradiene type of diterpenoid glycosides 1 and 2 that exhibited IC50s of 4.1 and 15.4µg/mL, respectively, against C. neoformans. The structures of compounds 1 and 2 were determined by chemical methods and spectroscopic analysis. It was noted that hydrolysis of the glycosides under drastic conditions afforded an artifact aglycone (4) due to the migration of the double bond between C-7 and C-8 in the genuine aglycone 3.