The cytotoxicity and chemical constituents of the hexane fraction of Typhonium flagelliforme (Araceace).

The plant, Typhonium flagelliforme (Araceae), commonly known as the "rodent tuber" in Malaysia, is often used as an essential ingredient of herbal remedies for alternative cancer therapies. The hexane extract of this plant was evaluated for cytotoxic activity against in vitro culture on P388 murine leukaemia cells and showed weak IC(50) of 15 microg/ml. The partial chemical constituents were identified as methyl esters of hexadecanoic acid, octadecanoic acid, 9-octadecenoic acid and 9,12-octadecadienoic acid. In addition, several common aliphatics were identified as dodecane, tridecane, tetradecane, pentadecane, hexadecane, heptadecane, octadecane, nonadecane and eicosane. The unique methyl ester of 13-phenyltridecanoic acid was isolated and positively identified using spectroscopic methods. None of the identified compounds showed or are known to have cytotoxic behaviour.

Acute renal failure in 2K2C Goldblatt hypertensive rats during antihypertensive therapy: comparison of an angiotensin AT1 receptor antagonist and clonidine analogues.

1. This study compared the effect of a non-peptide angiotensin II receptor antagonist and a series of clonidine analogues on blood pressure and renal function in a two-kidney two-clip Goldblatt rat model of hypertension subjected to 2 weeks of dietary sodium deprivation. 2. Animals received either vehicle, the angiotensin II antagonist, ZD7155 or structural analogues derived from clonidine (AL-11, AL-12 and CN-10) at 10 mg kg-1 day-1 for 4 days. 3. All groups of rats had systolic blood pressure in the hypertensive range (160-180 mmHg). ZD7155 caused a 33-mmHg fall in blood pressure (P < 0.05) and raised plasma urea and creatinine four- to six-fold. 4. AL-12 decreased blood pressure by 30 mmHg (P < 0.05), but had no effect on water intake, urine flow or plasma urea and creatinine. AL-11 and CN-10 had minimal effects on blood pressure and water intake and while CN-10 decreased urine flow on the third treatment day, AL-11 markedly reduced urine flow by some 70%. 5. These data show that in this sodium deficient renovascular model of hypertension, blockade of angiotensin II receptors normalizes blood pressure but causes renal failure, whereas the vasodepressor action of the clonidine analogue AL-12 occurs without detriment to renal function. These findings imply that angiotensin II receptor antagonists could lead to renal failure if used as antihypertensive agents in renovascular hypertension whereas this would be avoided with the use of clonidine-like analogues.