Noni juice (Morinda citrifolia): hidden potential for hyperkalemia?

We report the case of a man with chronic renal insufficiency who self-medicated with an alternative medicine product known as noni juice (Morinda citrifolia). The patient presented to the clinic with hyperkalemia despite claiming adherence to a low-potassium diet. The potassium concentration in noni juice samples was determined and found to be 56.3 mEq/L, similar to that in orange juice and tomato juice. Herbal remedies and alternative medicine products may be surreptitious sources of potassium in patients with renal disease.

Heterocyclic derivatives of 3-substituted-1,1,1-trifluoro-2-propanones as inhibitors of esterolytic enzymes.

A series of (alkylthio)trifluoropropanones containing a heterocyclic moiety was synthesized. The compounds were tested for in vitro inhibition of four hydrolytic enzymes including insect juvenile hormone esterase (JHE), eel acetylcholinesterase (AChE), yeast lipase (LP), and bovine alpha-chymotrypsin. The I50 values ranged from 10(-3) to 10(-7) M. 3-(2-Pyridylthio)-1,1,1-trifluoro-2-propanone was found to be the most potent inhibitor as compared to the other tested heterocyclic analogues with an I50 value of 98 nM against JHE from the fifth-instar larvae of Trichoplusia ni. Results from X-ray crystallography showed that the compound exists in a tetrahedral gem-diol form stabilized by an intramolecular hydrogen bond in the solid state. X-ray crystallography of a less potent inhibitor, 3-(4-pyridylthio)-1,1,1-trifluoro-2- propanone, showed that it also exists in the hydrated form, but it lacks an intramolecular hydrogen bond. These results provide indirect support that trifluoromethyl ketones are transition-state mimic inhibitors of esterases, and the bearing of the results on the transition-state mimic theory is discussed. The I50 values against AChE were in the micromolar range. Compounds containing a imidazolyl, triazolyl, and pyrimidyl moiety showed the highest inhibition of this enzyme. Differential selectivity of inhibition was associated with the bond distances between the nitrogen and the carbonyl group as in the natural substrate, when measured in the molecules in their minimal energy conformations. Inhibition of LP was moderate to weak, when compared to JHE and AChE. None of the tested compounds showed significant inhibition of alpha-chymotrypsin.(ABSTRACT TRUNCATED AT 250 WORDS)