Unusual Flavones from Primula macrocalyx as Inhibitors of OAT1 and OAT3 and as Antifungal Agents against Candida rugosa.

A bioactivity guided program exploring the interaction of phytochemicals in the entire plant Primula macrocalyx with the organic anion transporters (OAT1 and OAT3) and microorganisms led to the elucidation of ten known flavones (1-4, 6-10, 12) and two previously undescribed flavones (5, 11). The structures of the compounds were determined by extensive analysis of spectroscopic data, as well as by comparison with data from previous reports. Two known flavones (9, 12) are reported for the first time from the family Primulaceae. All compounds were evaluated for inhibition of OAT1 and OAT3. Six flavones (2, 3, 6-8, 12) showed potent inhibitory activity on OAT1, while seven flavones (2, 3, 6-9, 12) showed marked inhibitory activity on OAT3, with IC50 ≤ 10.0 µM. Antimicrobial activities of crude fractions against sixteen microorganisms were tested to give a target yeast strain Candida rugosa for further evaluation of MICs on the isolates. Three flavones (7, 8, 12) showed marked antifungal activity with MIC < 2.0 µM. To our knowledge, this study is the first to evaluate these flavones as inhibitors of the OAT1 and OAT3, and as antifungal agents.

Isoflavones from Camphorosma lessingii Inhibit the Organic Anion Transporters OAT1 and OAT3.

Phytochemical investigation of Camphorosma lessingii has resulted in the isolation of four previously unreported isoflavones (1: -4: ) and eight known compounds (5: -12: ). Nine of these compounds (1: -6, 8: -10: ) are reported for the first time from members of the family Amaranthaceae. The structures of all isolated compounds were determined by spectroscopic methods, primarily one-dimensional and two-dimensional nuclear magnetic resonance and mass spectrometry. The absolute configuration of 6: was confirmed by circular dichroism. Inhibition of the organic anion transporters, OAT1 and OAT3, by the isolated compounds was evaluated. Among them, 7, 2'-dihydroxy- 6,8-dimethoxyisoflavone (1: ), 2'-hydroxy-6,7,8-trimethoxyisoflavone (2: ), 6,2'-dihydroxy-7,8-dimethoxyisoflavone (3: ), and 7-methoxyflavone (5: ) showed a significant inhibitory effect on 6-carboxyfluorescein uptake mediated by OAT1 and OAT3.