Botanically called Citrullus lanatus, watermelon belongs to the plant family Cucurbitaceae. It is a fruit cultivated and consumed in Africa for its essential nutrients, which are very beneficial to the human body. Previous investigations on watermelon have highlighted its antioxidant activities, anti-inflammatory effects and several essential nutrients. Intake of watermelon has been associated with a reduced incidence of many diseases.
Watermelon fruit is a very rich source of vitamins A and C, and the therapeutic effects of the fruit have been reported and attributed to its antioxidant and certain phytochemical compounds. For instance, beta-carotene and lycopene have been established to play a key role in the treatment of cancer and cardiovascular diseases.
But results of a recent study published in European Journal of Medicinal Plants showed that, compared to control rats, administration of the methanolic extract of the rind watermelon (Citrullus lanatus) significantly enhanced sperm count and all reproductive hormone levels; and also caused non-significant increases in sperm motility, percentage of spermatocytes with normal morphology and percentage of live spermatocytes, but decreased percentage of dead spermatocytes.
The study titled “Ameliorative Effects of the Methanolic Extract of the Rind of Citrullus lanatus on Lead Acetate Induced Toxicity on Semen Parameters and Reproductive Hormones of Male Albino Wistar Rats” was conducted by Nigerian researchers, which include T. A. Kolawole from the Department of Physiology, Madonna University Elele Campus, Rivers State; and D. V. Dapper and S. O. Ojeka from the Hemorheology and Immunology Research Unit, Department of Human Physiology, College of Health Sciences, University of Port Harcourt, River State. According to the researchers, treatment with lead acetate caused a significant reduction in levels of all reproductive hormones and significant diminution of sperm motility, morphology, and viability; with increases in percentage of dead spermatocytes.
They noted: “Expectedly, co-administration of the methanolic extract of the rind of Citrullus lanatus with lead acetate ameliorated the deleterious effects of lead acetate resulting in significant increases in sperm count and all reproductive hormones and non-significant increases in motility, morphology and live spermatocytes: however, the percentage of spermatocytes with abnormal heads were significantly increased.
“The results suggest that the methanolic extract of the rind of Citrullus lanatus exerts a possible ameliorative effect on lead acetate induced toxicity on some reproductive parameters in male albino Wistar rats.” The researchers concluded: “The findings suggest that the methanolic extract of the rind of Citrullus lanatus exerts a possible beneficial effect on male reproductive parameters in albino Wistar rats and validates anecdotal reports of the beneficial effect of watermelon consumption from our environment. We however, recommend further studies in this regard.”
The study investigated the effects of the methanolic extract of the rind of Citrullus lanatus on lead acetate induced toxicity on semen parameters, reproductive hormone assay and testicular histology in male albino Wistar rats. Twenty male rats were assigned into four groups: Group A to D of five rats each. Group A served as control and received 2ml/kg bw of 10 per cent extract vehicle; Group B received 200mg/kg bw of the methanolic extract of the rind of Citrullus lanatus; Group C received 2.25mg/kg bw of lead acetate; and Group Dwere co-administered with 2.25 mg/kg bw lead acetate and 200 mg/kg bw of the methanolic extract of the rind of Citrullus lanatus.
The drugs and extracts were administered orally to the rats for 35days. On day 36, blood samples were collected from anaesthetized rats by cardiac puncture for reproductive hormone assay and the testes harvested for determination of semen parameters and histological studies. Semen parameters: count, motility, viability, and morphology were determined and assay for plasma levels of Follicle Stimulating Hormone (FSH), Luteinizing Hormone (LH) and testosterone done.
Another study published in Food and Nutrition Sciences by Adewale Adetutu, Olubukola Sinbad Olorunnisola, and Olusoji Abiodun Owoade of Ladoke Akintola University of Technology, Ogbomoso, Oyo State, examined the nutritive values and antioxidant activity of Citrullus lanatus fruit extract. The present study evaluated the nutritive contents, free radical scavenging activities and phytochemical components of C. lanatus fruit.
The extract of the fruit was subjected to in vitro antioxidant assessment using 1, 1-di-phenylpicryl-hydrazyl radical (DPPH) and hydrogen peroxide radical scavenging assays. The results of this study showed that C. lanatus fruit had very high moisture content and its crude protein; crude fat, crude fibre and ash content were all in traceable amounts. The sugar content was considerably high in comparison with other nutritive contents.
Lycopene and β-carotene contents of C. lanatus-fruit were estimated to be 4537.83 and 308.71μg/100g respectively. The gross energy evaluation showed a value of 0.335 Kcal/g. The fruit extract exhibited significant DPPH (IC50 of 0.10mg/ml) and hydrogen peroxide radicals scavenging activity (IC50 of 0.62 mg/ml) in comparison with the positive control
Butylated hydroxytoluene (BTH).
This study therefore recommends that C. lanatus fruit could be an excellent source of antioxidants, which may prevent diseases whose pathogenesis involves oxidative stress. The researchers concluded: “The methanol extract of C. lanatus fruit exhibited substantial free radical scavenging activities. This suggests that the fruit is an important source of natural antioxidant and this potential could be attributed to its flavonoids contents, lycopene and beta-carotene quantified in this study.
“Consequently, this property makes C. lanatus fruit an interesting target as a good source of antioxidants to prevent or ameliorate diseases whose pathogenesis involves oxidative stress. Therefore, the strong antioxidant properties and the presence of phytochemicals in C. lanatus fruit may justify its popular consumption and usage in herbal medicine. Hence, further research on the bioactivity of its active ingredients could provide more information about the mechanism of action of its various therapeutic values.”
Another study published in Sky Journal of Microbiology Research evaluated the efficacy of crude extract and fractions of Citrullus lanatus against some selected microorganisms. The researchers from Usmanu Danfodiyo University, Sokoto; Gombe State University, Gombe; and University of Lagos, Akoka Yaba, Lagos, evaluated the antimicrobial activity of the crude extract and respective fractions of C. lanatus leaves against clinical isolates including, Streptococcus pyogenes, Streptococcus faecalis, Bacillus cereus, Corynebacterium ulcerans, Escherichia coli, Klebsiella pneumoniae, Pseudomonas flourescens, Salmonella typhi, Candida albicans and Candida krusei using agar diffusion and broth dilution methods.
“Susceptibility test of all the fractions revealed significant activity against the test microbes. Ethylacetate fraction exhibited the highest activity with inhibition range of 26–29mm and the methanol extract showed the least activity with inhibition range of 16–18mm against all the test organisms except S. pyogenes, C. ulcerans, K. pneumonia and S. typhi.
“The Minimum Inhibitory Concentration (MIC) range was 1.25–5mg/ml and the Minimum Bactericidal/Fungicidal Concentration (MBC/MFC) range was 2.5–10mg/ml against the susceptible organisms. Antimicrobial potency of the extract and fractions was in the order; EF> CF> BF>HF>ME.
“The result of this re search suggests that the leaves of C. lanatus have a remarkable antimicrobial activity which validates the ethno medicinal claim.” Another study published in American Journal of Food and Nutrition examined the effect of fortified bread with defatted cake of Citrullus lanatus on blood biochemical parameters in rat.
The Ivorian researchers found that wheat flour bread fortification with defatted cake of Citrullus lanatus modified blood biochemical parameters. The researchers concluded: “According to this study, the fortification of bread with defatted cake of Citrullus lanatus are provoke change on blood biochemical parameters such as glycaemia, uraemia, blood cholesterol of animals which consumed these diets. On the other hand, others parameters such as blood creatinine, blood triglyceride and the ratio calcium/phosphorus do not show change when compared to that obtained on rats which consumed the classic diet (RTC) and the classic bread (RPC).
“Complementary studies will be useful to determine whether the change observed have biometric and histopathological consequences on the nutritional regulating organ of metabolism.”
For your news articles, press release, Breaking News, send e-mail to [email protected]