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.