Effects of Mucuna prurita seeds on sexual behaviour of male rats

In Sri Lanka, in the Ayurvedic medicine, seeds of Mucuna prurita (both with seed coats and without seed coats) are recommended to be used as an aphrod isiac. However, the validity of this claim is not established. The aim of t his study was to test the aphrodisiac potential of M. prurita seeds using a powdered suspension in 1% methyl cellulose. Male rats were treated orally with different doses of whole powdered seed suspension (WPSS) [1,500 mg/kg (n = 12) once a day; 1,500 mg/kg (n = 12) twice a day or 1,500 mg/kg (n = 1 2) three times a day] or decoated powdered seed suspension (DPSS) [1,500 mg /kg (n = 12) twice a day and 1,500 mg/kg (n = 6) three times a day] or vehi cle. The male sexual behaviour of these rats was monitored 2 h later. The D PSS had no effect whatsoever on male sexual behaviour. In contrast, mid and high doses of the WPSS caused a marked reduction in pre-coital sexual beha viour (in terms of chasing, genital grooming, anogenital sniffing), failure of rats to mount, intromit or ejaculate and prolongations of latencies to mount and intromit. In addition, the mid dose of WPSS caused a prolongation of intercopulatory interval. These impairments of sexual behaviour were re versible. The mid dose also had marked sedative (in terms of impairment of numbers of rear, head dips, locomotory activity) and analgesic (marked prol ongation of reaction time in both tail flick and hot plate test) effects. T his dose inhibited neither muscle strength (assessed by a bar holding test) nor muscle co-ordination (Bridge test). We conclude that the WPSS of M. pr urita seeds inhibited libido, sexual arousal/motivation and penile tactile sensitivity without disrupting sexual performance. Med Sci Res 27:375-378 ( C) 1999 Lippincott Williams & Wilkins.