Abstract
Cocos nucifera (coconut) is from Arecaceae family and is a known crop consumed as dietary fruit due to its refreshing taste. All parts of C. nucifera are useful but little is known of the husks for medicinal purposes apart from its household importance. On the other hand, using the husks extract as aphrodisiac or to improve libido is yet to be studied as far as we know. Therefore, this study was to examine the influence of C. nucifera husks on histology of internal genitals and copulation behavior in male rats. Another objective was to investigate the effects of coconut husks on hormonal profile of experimental rats. Seven matured coconutswere purchased from the market, and were identified and authenticated by an expert taxonomist. Coconut mesocarp (husks) was removed from the shell, cut into little pieces, washed thoroughly and air-dried for 21 days. The dried fiber was grinded with a blender into uniform powder, and sieved. About 500g of the powder was separated in a Soxhlet apparatus with 500 ml of ethanol was used as solvent and concentrated using a rotary-evaporator. 25 male wistar rats aged: 2-3months with average weight (162.3g), ranged (146.2g to 178.6g) were purchased from the animal house of the Department of Animal and Environmental Biology, University of Benin, Nigeria. Rats were housed in metal gauze cages with saw dust as beddings and allowed to acclimatize in the same facility for 7 days before commencing experimentation, which was conducted in an ambient temperature (24 ± 5ºC), humidity 45-50% and photo period 12:12 hours. Rats were fed with standard feeds pellets (Growers mash, Vital Feed, Grand Cereal, Nigeria) and were given water as required. Animals were treated with utmost care in line with laid down regulation for handling experimental animals. Each rats were monitored for daily gain in body weight while food consumed per day was also recorded in g/day. Animals were monitored for behavioral signs of acute toxicity following modified Lorke’s method for LD50 of C. nucifera husks extract. Five (5) groups were arranged into control (A) and treatment (B to E), n=5 per group). Graded dose: 25mg/ml, 50mg/ml, 75mg/ml and 100mg/mL were administered by oral intubation once daily for 48days using orogastric tube. Copulation behavior test was monitored by two trained expert observers in a sound-attenuated room. A rectangular Plexiglas monitoring chamber measuring (45cm × 40cm × 30cm) was used. Female rats were introduced into the observation chamber (n=25), which was conducted on day 16th, 32nd and 48th after extract consumption. Blood sample was collected from the marginal ear vein for hormonal assay before extracts administration and midway in the experiment. After experimentation, all rats fasted overnight before being euthanized through decapitation. Blood was also collected via cardiac puncture to determine final analysis for hormonal assay using ELISA method. Internal male genitalia (testes, epididymis, seminal vesicle and prostate gland) were harvested, grossed and processed histologically before staining with H&E and examined through the microscope. Data were analyzed using Instat Statistic Package version 3 and expressed as mean ± SEM. ANOVA was used to compare the mean differences between and within each group. Turkey’s post-hoc was used for pairwise comparison between groups. Values with difference in superscript were considered significant (P ≤ 0.05). The results showed that no morbidity or mortality was observed throughout the study while treated sections were without pathological lesions (Plate 4.1 to 4.20). Average weight of rats and food consumption per day were 162.4g and 10.2±1.7g/day. Body weight decreased remarkably in high dose treated rats: 75mg/ml (5.72 ± 1.5↓↓); 100mg/ml (6.77 ± 2.8↓↓). Copulation behavior was measured based on the following parameters: mount latency- time from introduction of a female until the first mount; Intromission latency- time from introduction of a female until the first vaginal penetration; Ejaculation latency- time from the first penetration till ejaculation; Mount frequency- number of mounts before ejaculation; Ejaculation frequency- number of ejaculations from the time a female is introduced to the chamber; Intromission frequency- number of vaginal penetration before ejaculation; Post-ejaculation interval- time from ejaculation to the next penetration; and Inter-intromission interval- an average interval between successive vaginal penetrations. From the foregoing, therefore, astriking increment particularly in intromission frequency was observed from the lowest dose (12.22 ± 1.32) to the highest dose (22.01 ± 1.67) compared to control (9.97 ± 0.68), which indicated that elevated values were dose dependent (Table 4.2). In a similar gesture, mount frequency was observed to have risen from (4.89 ± 0.27 to 9.66 ± 0.79), but was not significant (p = 0.063).Correspondingly, mount latency (ML), inter-intromission interval (III) and intromission latency (IL) decreased significantly (p ≤ 0.05) while reduction in post-ejaculation interval (PEI) was singularly not significant statistically (p ≥0.133).Table 4.3 showed that there were improvements in elevated values: mount frequency (5.27 ± 0.14 to 13.88 ± 1.32), ejaculation frequency (5.14 ± 0.13 to 13.71 ± 0.63), intromission frequency (16.01 ± 1.26 to 32.82 ± 2.63) and ejaculation latency (6.88 ± 0.44 to 11.93 ± 0.05) compared to controls (3.96 ± 0.92; 2.77 ± 0.36; 9.56 ± 0.53; and 4.35 ± 0.16). On the other hand, mount (159.16 ± 1.02 to 121.01 ± 1.82) and intromission (102.44 ± 2.98 to 83.96 ± 2.88) latencies including post ejaculation (4.21 ± 0.45 to 2.83 ± 0.52) and inter-intromission (25.03 ± 1.72 to 16.23 ± 1.78) intervals all decreased in responses to increasing dosage compared to untreated rats (mount=273.02 ± 1.64; intromission=121.83 ± 2.23; post ejaculation=5.15 ± 0.29 and inter-intromission=40.82 ± 2.31). Table 4.4 highly suggests all parameters either increased (mount, ejaculation and intromission frequencies, and ejaculation latency) or decreased (mount and intromission latencies, post-ejaculation and inter-intromission intervals) where necessary and were statistically significant (P ≤ 0.05) excluding ejaculation latency (p = 0.179). Similarly, a significant increase in the level of Testosterone (p ≤ 0.001) and marked decreases of LH and FSH (p ≤ 0.05) during experimentation were notable. Testosterone level in 100mg/ml increased: from (3.82 ± 0.6ng/dL), to (4.92 ± 0.5ng/dL), and lastly to (5.14 ± 0.3ng/dL) after experimentation. The results also showed a corresponding decrease in values of LH: from 2.92 ± 0.6IU/L; to 2.22 ± 0.5IU/L; and 2.13 ± 0.3IU/L in the end while FSH reduced: from (2.28 ± 0.7IU/L), to (1.77 ± 0.7IU/L), then to (1.58 ± 0.3IU/L), and were statistically significant across board (p ≤ 0.05). In conclusion, C. nucifera fibre is not injurious to histology of male internal genitalia even at 100mg/ml. It also retains sexual enhancing effects and validates the use of the extract for improving male copulation effects. All in all, reduced weight and improved level of male hormones clearly contribute to sexual competence in male rats. However, further research is advocated to compliment the above claims and to establish safe dose regime.
