Aqueous extract from Ficus capensis leaves inhibits key enzymes linked to erectile dysfunction and prevent oxidative stress in rats' penile tissue

ContextFicus capensis Thunb (Moraceae) is a medicinal plant widely grown in tropical and subtropical regions with the leaf decoction commonly taken in traditional folklore as fertility agent in men for ages.AimThis study investigated the effects of aqueous extract from Ficus capensis leaves on angiotensin-I-converting enzyme (ACE), acetylcholinesterase (AChE) and arginase activities in vitro. The antioxidant properties of the extract as typified by the abilities to scavenge radicals [nitric oxide (NO), hydroxyl (OH)], chelate Fe2 +  and inhibit Fe2 + -induced lipid peroxidation were also assessed.MethodsThe aqueous extract (1:10 w/v) of Ficus capensis leaves was prepared and the ability of the extract to inhibit arginase, angiotensin I –converting enzyme (ACE), acetylcholinesterase (AChE) and antioxidant properties of the extract in rat’s penile tissue in vitro was investigated using various spectrophotometric methods. Phenolic constituent was carried-out using high performance liquid chromatography coupled with diode array detection (HPLC - DAD).ResultsThe extract inhibited ACE (IC50 = 52.17), AChE (IC50 = 172.60 μg/mL) and arginase (IC50 = 112.50 μg/mL) activities in a dose-dependent pattern. Gallic acid, quercetin, caffeic acid, ellagic acid, rutin and chlorogenic acid were the most abundant phenolic compounds identified in the sample. Furthermore, extract scavenged NO (IC50 = 0.12 μg/mL) and OH (IC50 = 0.53 μg/mL) radicals, chelated Fe2 +  (IC50 = 0.16 μg/mL) and inhibited Fe2 +  lipid peroxidation (IC50 = 435.17 μg/mL) dose-dependently.ConclusionInhibition of ACE, AChE, arginase, Fe2 + -induced lipid peroxidation as well as radical scavenging and Fe2 + -chelating abilities could be some of the possible mechanisms by which F. capensis leaves could be used in the treatment/management of erectile dysfunction (ED).