Erection-stimulating, anti-diabetic and antioxidant properties of Hunteria umbellata and Cylicodiscus gabunensis water extractable phytochemicals.

Background Herbs have been used as an aphrodisiac since ages. This study was designed to investigate the effects of Hunteria umbellata (HU) seeds and Cylicodiscus gabunensis (CG) stem barks aqueous extracts on key enzymes relevant to erectile dysfunction (phosphodiesterase-5 and arginase) and type-2 diabetes (α-amylase and α-glucosidase). Methods In ascertaining the erectogenic and antidiabetic properties of the extracts, the effects of the extracts on activities of some enzymes relevant to erectile dysfunction (arginase and phosphodiesterase-5) and type-2 diabetes (α-amylase and α-glucosidase) were determined. Antioxidant properties of the extracts were assessed through several antioxidant assays (DPPH˙, OH˙). Furthermore, their phenolic constituents were estimated and quantified using HPLC. Results The results revealed that both extracts inhibited α-amylase and α-glucosidase in a concentration-dependent manner. HU showed higher α-amylase (IC50=221.30 µg/mL) and α-glucosidase (IC50=184.35 µg/mL) inhibition than CG. Also, both extracts inhibited phosphodiesterase-5 and arginase in a dose-dependent manner in vitro; nevertheless, HU showed higher inhibition [phosphodiesterase-5 (IC50=539.72 µg/mL); arginase (41.53 µg/mL)] than CG [phosphodiesterase-5 (IC50=611.35 µg/mL); arginase (47.95 µg/mL)]. In addition, the extracts possess antioxidant properties through radical (DPPH and OH) scavenging and metal (Fe2+) chelating abilities. HPLC analysis of phenolic constituents revealed the abundance of gallic acid, chlorogenic acid, caffeic acid, ellagic acid and quercetin. Conclusions The ability of samples' extract to inhibit some of key enzymes relevant to erectile dysfunction and type-2 diabetes could render them cheap, natural and alternative therapy with erectogenic and antidiabetic potentials.