Analysis of papaya pulp from the city of Lubumbashi (Mzée Market) and that of Kinshasa (Selembao Market) shows a water content of 85.87% and 84.46% respectively. This shows that this climacteric fruit is very perishable, hence the many losses observed in the fruit markets. The moisture content of papaya is therefore included in the range of water contents of fresh fruits; this result is almost similar to that of Morris at al (9); and Muhamad at al (10) who worked on the same variety of papaya and found a water content of 83.53%.
Carica papaya fruit pulp collected in Lubumbashi and Kinshasa contains 0.53% and 0.59% total ash content respectively. These results show that papaya could be an excellent source of minerals. Our results are lower than those of Larraurie at al (11) and Martinez et al (12) who found respective contents of 2.85% and 5% on mango and papaya in 100g of pulp.
With regard to the mineral elements, the analysis of the samples revealed at the level of the macroelements for 100 g of dry matter, a potassium content of 200 ± 8 mg, magnesium 13.12 ± 3 mg, calcium 22.15 ± 2 mg, sodium 3 ± 0.5mg for papaya from Lubumbashi (Mzee Market) and 192.32 ± 8mg of potassium, 14.458 ± 3mg of magnesium, 20.58 ± 2mg of calcium and sodium 3.58 ± 0.5mg for papaya from Kinshasa (Selembao Market). These results show some inequalities in terms of content which would surely be due not only to the difference in soil composition but also to different cultivation and climatic conditions (13). With a potassium (200 ± 8mg; 192.32 ± 8mg) and calcium (22.15 ± 2 mg; 20.58 ± 2mg) levels, our results are slightly higher than those found by Lobo and Pastor,2012 who have found as potassium value 182mg and 18.61mg as calcium content on papaya pulp.
Regarding the trace elements, the analyzes showed as zinc content (0.29 ± 0.1 mg and 0.12 ± 0.1 mg), copper (0.02 mg ± 0.01 and 0.14 ± 0.01 mg), iron (2 ,22 ± 0.5mg and 2.04 ± 0.5mg). The results are almost different between the two sampling sites because of the environmental parameters mentioned above. Compared to the results found by Lobo and Pastor (14), some of the results of this study are superior as is the case of copper and iron. The contents of other elements are lower than those of Lobo and Pastor (14), namely: sodium (9.61mg), zinc (1.97mg).
The yield of extracts obtained after maceration of papaya seeds in palm wine is much higher than that of ethanol.The yield obtained after maceration of papaya seeds in palm wine of 34.07g or 154.86% was higher than that of ethanol 6.22g or 28.27%. These results are contrary to those of the studies conducted by Amazu at al. (15), and Rasha at al (16) in which the extraction of papaya seeds with palm wine had a higher yield than those of methanol but lower than that of an extraction made with absolute ethanol (15, 16).
Phytochemical screening revealed the presence of alkaloids, saponosides, tannins (catechics), flavonoids and anthocyanins in the palm wine and ethanol extract of Carica papaya seeds and an absence of cyanogenic glycosides. These results confirm those reported by Mangambu at al. who found the same result in papaya seeds (17).
Oral administration of a single dose of 5000 mg/kg of the palm wine extract and the ethanolic extract of the seeds of Carica papaya did not cause significant changes and no deaths were reported in mice. No signs of toxicity such as decreased sensitivity to pain, noise or locomotion were observed. The extracts have a toxicity index equivalent to 5, according to the scale of toxicity of a chemical substance according to the LD50 and the route of administration established by Hodger and Sterner (8). Other studies on aqueous and ethanolic extracts of Carica papaya leaves at a dose of 5000 mg/kg did not lead to any toxic effect. Administration of palm wine and ethanol extracts of papaya seeds for 14 days promoted weight gain in mice. These results correspond to those found by Etame at al, whose palm wine extract had promoted weight gain in rats (18).
The biochemical analyzes carried out showed an increase in the enzymatic activity of ASAT for the two extracts and a decrease in the activity of ALAT. These results relate to those found by Etame et al. (18). After biochemical analyses, the latter found an increase in ASAT in both sexes and at all doses as well as a decrease in ALAT in rats. ALAT activity is more specific for liver damage than ASAT activity. However, in our study, the variations in enzyme activity were not significant, compared to the values in the group of control mice.
The serum urea and creatinine assay revealed that the administration of the extracts did not cause any significant change. These results also relate to those found by Etame et al. (18). Serum urea and creatinine are considered the main markers of nephrotoxicity (19).