Abstract:
The therapeutic management of erectile dysfunction involves maximizing NO production through the
use of drugs such as sildenafil. It has become common practice to combine the use of Sildenafil with
natural therapy such as Lemon (Citrus limon) and lime (Citrus aurantifolia). Therefore, this study
evaluated the effect of lime and lemonjuices on the erectogenic properties of Sildenafil. The total
phenolic, flavonoid and vitamin C contents of the citrus juices were determined. Thereafter, the effect
of the juices and sildenafil on sexual behavior was assessed. Erectile dysfunction was induced in rats
with L-NAME (40 mg/kg body weight). The rats were divided into 11 groups (n = 6) and given the
following treatments: Group 1 - normal rats; Group 2 - L-NAME induced rats; Group 3 - Sildenafil
(5mg/kg); Group 4 = L-NAME + Lime (0.5mL/kg); Group 5 = L-NAME + Lime (1mL/kg); Group 6
= L-NAME + Lemon (0.5mL/kg); Group 7 = L-NAME + Lemon (1mL/kg); Group 8 = L-NAME +
Sildenafil (5mg/kg) + Lime (0.5mL/kg); Group 9 = L-NAME + Sildenafil (5mg/kg) + Lime (1mL/kg);
Group 10 = L-NAME + Sildenafil (5mg/kg) + Lemon (0.5mL/kg); Group 11 = L-NAME + Sildenafil
(5mg/kg) + Lemon (1mL/kg). Afterwards, the sexual behaviour and nitric oxide levels of the rats, as
well as the activities of phosphodiesterase-5 (PDE-5), arginase, angiotensin-1 converting enzyme
(ACE), monoamine oxidase (MAO), nucleotidases, and antioxidant status were assessed. The results
revealed that lemon had significantly higher total phenol (13.04 mg GAE/L), flavonoid (7.38 mg QE/L)
and vitamin C contents (26.43mg/L) compared to lime [total phenol (10.42 mg GAE/L); total flavonoid
(5.19 mg QE/L); vitamin C (13.47 mg/L)]. Furthermore, the juices improved sexual behaviour in rats
by improving NO production and inhibiting the activities of PDE-5, arginase, ACE, MAO, ATPdase,
AMDpase and activated antioxidant enzymes. In conclusion, this study showed that administration of
lime at 1.0 mL/kg enhanced the therapeutic potential of Sildenafil. While, lemon (0.5 mL/kg and 1.0
mL/kg) and lime (0.5 mL/kg) did not show any synergistic effect.
