Plasma ACE activity was determined using rat plasma. The IC50 of the conventional ACEI, captopril was determined to test the sensitivity of the assay. At least three separate determinations were conducted for each test compound. A tannin test was only conducted on those plant extracts that exhibited over 50 percent ACE inhibition in the initial analysis. The data was subjected to GraphPad Instat (GraphPad Software Inc, San Diego, CA, USA). All values were expressed as mean ± SEM. A probability where p<0.05 was considered significant.
Results: Eight of Sixteen Plants Showed ACEI
Eight of the 16 plants demonstrated ACE inhibition activity. The plants were then subjected to a gelatin salt block test for tannins to eliminate any false positive results. None of the plants tested positive for tannins, hence eliminating any false positive results.
Ultimately, the eight plants that showed significant ACEI activity in both extract forms were: Amaranthus dubius, Amaranthus hybridus, Asystasia gangetica, Galinsoga parviflora, Justicia flava, Oxygonum sinuatum, Physalis viscosa, and Tulbaghia violacea.
The Stand Out "Wild Garlic" (Tulbaghia violacea) Plant
Only one plant -- Tulbaghia violacea -- showed more than 50 percent inhibition in both extract preparations. These findings are in keeping with those of another group (1999). Further testing has revealed that the plant has promising hypotensive affects. The plant is commonly associated with onions and garlic and highly concentrated in Southern Africa. It is best known as "wild garlic."
Researchers have recorded (1962) that the plant was pounded into formulations and used by native South Africans to relieve stomach ailments, rheumatism and high fevers. Other researchers found (1966) that native South Africans rubbed the leaves of the plant on the head for sinus headaches and used plant infusions for colic and restlessne
Source:American Physiological Society