Isolation and characterization of flavonoids from roots of Rauvolfia serpentina and evaluation of their hypotensive potential through angiotensin-converting enzyme (ACE) inhibition mode of action

The purpose of this research was to characterize and identify novel bioactive flavonoids in Rauvolfia serpentina roots as natural, safe, and efficacious angiotensin-converting enzyme (ACE) inhibitor for the management of antihypertension. Firstly, total flavonoids were extracted from Rauvolfia serpentina to evaluate the ACE inhibition potential. The extracted total flavonoids showed greater ACE inhibition potential (79.9 ± 0.42%) than the standard captopril (72.12 ± 0.35%) which is synthetic hypotensive drug. These flavonoids were further purified using column chromatography, and their potential to inhibit the angiotensin-converting enzyme was determined. Only the third fraction (F3) exhibited ACE inhibitory potential compared to the other seven purified fractions. The F3 fraction was analyzed with LC–ESI–MS/MS to determine which flavonoid compound inhibited ACE. The flavonoid compounds recognized as ACE inhibitors from Rauvolfia serpentina included pinocembrin, quercetin, galangin-5 methyl-ether, apigenin, pseudobaptigenin, quercetin dimethyl ether O-glucuronide, and myricetin 3 O-glucoside, luteolin 7-O glucuronyl, rutin, and quercetin -3- O hexose-pentose. The finding of this research indicates that the root of Rauvolfia serpentina contains several different medicinal flavonoids possessing the capacity to control hypertension through angiotensin-converting enzyme inhibition mode of action.