Molecular mechanisms that underlie the sexual stimulant actions of Avicennia marina [Forssk.] Vierh. and Crocus sativus L

The effects of extracts and sub-fractions of Avicennia marina, Crocus sativus and sildenafil on the sexual behavior of male rats and their effects on the intracavernosal pressure [I.CV], intracavernosal cyclic GMP and dihydrotestosterone plasma level were examined. The sexual behavior was followed for four hours using infra-red video cameras to quantify the effects on various male sexual behaviors. The results revealed that the active sub-fraction in case of A. marina was the hexane fraction of the chloroform extracts [C/H] whereas that of C. sativus was the hexane fraction of the alcoholic extract [A/H]. [C/H], [A/H] and sildenafil significantly increased the total sexual stimulation index from 53.8 +/- 2.7 [control] to 406 +/- 7.8, 225 +/- 4 and 401 +/- 30.1, respectively [P<0.001, N=6]. They significantly increased the index of successful mounting and ejaculation from 2.6 +/- 0.5 [control] to 40 +/- 2.7, 21 +/- 2.3 and 18 +/- 1.7, respectively [P<0.01, N=6]. They significantly increased the cyclic GMP level from 0.94 +/- 0.07 [control] to 3.1 +/- 0.13, 1.59 +/- 0.11 and 3.66 +/- 0.19 ng/mg wet tissue, respectively [P<0.05, N=7]. They did not affect dihydrotestosterone plasma level. [C/H], [A/H] and sildenafil increased the [I.CV] pressure by 4.8 +/- 0.3, 1.4 +/- 0.8 and 4.2 +/- 0.9 mmHg. The [C/H] seemed to be more active than sildenafil and twice active than [A/H]. Both extracts and sildenafil acted via an increase in cyclic GMP