POTENTIAL NUTRITION OF LEAVES AND FRUITS OF DIALIUM ANGOLENSE WELW. EX OLIV. (FABACEAE) AN ANTIMALARIAL PLANT FROM THE EASTERN OF DR CONGO

Dialium angolense were investigated to assess to the nutritive potentiality of his leaves and fruits and their implication in curative management of malaria using Standard analytical methods. The analysis showed that the carbohydrates, two as


Minerals determination:
Mineral analysis was performed following the procedure describe by previously (Dos Santos et al., 2016). Briefly, 500 mg were incinerated for 24h at 550 °C (Muffle Furnace mLs1200, Thermo Scientific, Madrid, Spain), weighed and desilicated with 3 mL of 40% HCl (Sigma-Aldrich, Saint-Quentin Fallavier, France) and 1 mL 70% HNO 3 (Sigma-Aldrich , Saint Louis, USA). The obtained solution was then evaporated at 90 °C to dryness. The residue was mixed with 50 mL distilled water followed by filtration. Detection of Sodium, Potassium, Calcium, Magnesium, Phosphorus, Copper, Zinc, and Iron, Manganese, Cadmium, Chrome, Nickel, Vanadium were realized using inductive coupled plasma atomic emission spectrometry (ICP-AES, Varian Vista) with coupled charge device detector (Agilent France, Massy). All the standards were obtained from Fisons Scientific Equipment (Loughborough, England). Quantification of element concentrations was done using specific calibration of 5 points for each element in the range 0-1000 mg/L. The limits of quantification (LOQ) related to samples were 0.0500 mg/ 100 g for Ca, K, Na, Mg P and 0.0010 mg/100 g for Fe, Zn, Mn, Cu, Cr, Ni, V.

Statistical analysis:
All the tests were carried out in triplicate and the results are expressed as mean ± Standard deviation. In bivariate analysis, the T Student Test was used and in multivariate analysis, the one-way ANOVA test. The significance level of the test was set at 95%.

Results:-Organic elements:
In Overall, organic matter is more abundant in fruit than in leaves (p <0.01) except in fat. In leaves, the amounts of these organic materials vary between 3,02 ± 0,40mg / 100g (FB) and 73.21 ± 0.42 mg / 100g (ST). The reducing sugars (18.06 ± 0.11 mg / 100g) and the total proteins (17.5 ± 0.11 mg / 100 g) are in the same proportions. This similarity is not observed in fruits where SR is abundant than PT (p <0.001). The organic acids (3.12 ± 0.21 mg / 100g) and fatty acids (2.04 ± 0.42 mg / 100 g) are in the same proportions (Table 1).

Macro and micro-elements:
The Dialium angolense leaves contains macro-elements whose values vary between 2.6 ± 0.3 mg / 100 g (K) and 71.1 ± 0.1 mg / 100g (Na). Its micro-elements vary between 0.1 ± 0.4 mg / 100g (Mn) and 30.1 ± 0.1 mg / 100g (Fe). For the macro-elements, fruits are richer than leaves (p <0.00001) except potassium for which the contents are in the same proportions. The same is true for micro-elements for which the contents are higher in the fruit than the leaves (p <0.00001) except for the iron concentrations for which the situation is reversed (p <0.001).The concentration of metals is generally the same between the leaves and the fruits.One hundred grams of the leaves or fruits of Dialium angolense can cover the daily requirements of K, Mg, Fe (leaves), Cu, Zn, Mn (fruits), Ni, V in an adult weighing 70 kg ( Table 2).

Vitamines:
In D. angolense, vitamins vary between 0.20 ± 0.02 mg / 100g (B9) and 17.20 ± 0.10 mg / 100g (vitamin C) in the leaves and from 0.61 ± 0.03 mg / 100 g (B9) at 24.10 ± 0.31 (vitamin C) in fruits. Overall fruits contain higher amounts of vitamins than leaves (p <0.01). Both, the leaves and the fruit, 100 g can cover the daily needs in humans of vitamins A, B1, B6 and B9. Fruits can also cover daily vitamin E requirements; for vitamin C requirements, 5 times more leaves and three times more fruit would be required (Table 3).

Organic acids and polyphenols:
In Dialium angolense organic acids are in the same proportions in the leaves as in the fruits and vary between 0.22 ± 0.11 mg and 0.73 ± 0.11 mg per 100g of dry matter. Total polyphenols, total flavonoids and total tannins are more abundant in fruits than in leaves (p <0.00001) and vary between 13.30 ± 0.11 mg EAG and 161.21 ± 0.12 mg EQC per 100 g of material dried (Table 4).

Dry matter, Ash, total acidity:
In Dialium angolense the total acidity is less than 0.4 molar. It has the same amplitude as much in the leaves as in the fruits. Total ash and dry matter have higher contents in the fruits than in the leaves (p <0.0001 and p <0.00001) where they oscillate respectively around 9.1% and 89.9% ( Figure 5).

Discussion:-
In this study, we provide the first data on the nutrients of Dialium angolense, a plant used in the eastern DR Congo in the management of malaria; at the same time, we present a path of reflection on the likely implication of its nutrients during the management of this parasitosis. . Leaves of D. angolense (100g) are richer in mineral elements than some leaves' vegetables commonly used in the normal diet in Sub-Saharan Africa. This is particularly the case for Na (71.1 ± 0.1 mg) whose values are higher than those of the leaves in Amaranthus spinosus or Mg (45.2 ± 0.1 341 mg) whose the values are twenty times higher than those of Hibiscus sabdarifa (2 mg). Its iron values are higher than those of several other vegetables, Ipomea batatas (16 mg), Hibiscus sabdarifa (3.2 mg) and Amaranthus spinosus (12.28 mg). They are richer in Ca than Ipomea batatas (28 mg) and Hibiscus sabdarifa (2.4 mg); richer in Zn than Moringa oleifera (0.85 mg), I. batatas (0.08 mg) and H. sabdarifa (4.8 mg). The fruits of D. angolense are richer in Mg (97.45 ± 0.2 mg); Ca (325.58 ± 0.1 mg); P (90.1 ± 0.1 mg); K (8.81 ± 0.2 mg); Na (9020.12 ± 0.1 mg) and Fe (4.47 ± 0.2 mg) than Dialium guineense (Ayessou et al., 2014;Besong et al., 2016) and richer in Mg (10 mg), Ca (24 mg), Na (3 mg), Zn (0.088 mg), Cu (0.1 mg), Mn (0.04 mg) than Carica papaya (Chukwuka et al., 2013;Rajasekhar, 2017).
Other non-organic elements such as Cd, Cr, Ni and V are also found in leaves and fruits of D. angolense in trace amounts ( Table 2). Cd has no known physiological role in humans (Godt et al., 2006) although it is accumulated by some fabaceae (Mahajan & Kaushal, 2018) but not by D. angolense as it has just been proven in the present study. Chromium (III)(Cr3 +) is an essential trace element, which is required for normal protein, fat, and carbohydrate metabolism (Swaroop et al., 2019) witch involved in the functioning of insulin (Cefalu & Hu, 2004) probably to improve the disease-associated disturbance of lipid profile and insulin resistance (Talab et al., 2020); but in its form Cr 4+ or Cr 6+ ,it is harmful and can cause ulcer, dermal irritations, allergies, effects on the respiratory tract, on the kidney and on the cardiovascular system, cariogenic, mutagenic, and teratogenic effects (DesMarias & Costa, 2019). In this study, we encountered it in the leaves of Dialium angolense in normal thresholds. It is suggested that as a trace, as in this study, Nickel is essential to the nitrogen cycle, to the production of prolactin, in the synthesis and activity of several enzymes including hydrogenases and could interfere in the oxidation of Iron (Al-fartusie & Mohssan, 2017). However, in most cases, it is more toxic than beneficial. It can cause lung cancer, pulmonary fibrosis, and even cerebral edema (Buxton et al., 2019;Genchi et al., 2020). Vanadium, in low doses, as in the doses encountered in the leaves of Dialium angolense during this study, is endowed with several therapeutic potentials in humans. It would prevent diabetes, has antiviral, antibacterial, and antiparasitic properties (Al-fartusie & Mohssan, 2017). At higher doses, harmful effects on the reproductive system and nephrotoxicity are reported, but natural antioxidants can play a role in reducing this toxicity (Zwolak, 2020). In Dialium guineense, levels of total polyphenols of 579 ± 6.013 mg EGA / 100g and total flavonoids: 19.45 ± 3.18 mg EQ / 100 g has been reported (Ayessou et al., 2014) in leaves.Therefore, it has lower polyphenol values than D. angolense.Tannins are reported to be anti-nutritional factors (S. . However, they have some properties such as the ability to induce a reduction in food bolus or an enzyme inhibition or the ability to promote protein digestibility. These properties may partly explain the presence of tannins in several food supplements, as reported (Sieniawska & Baj, 2017). Their presence in the leaves and fruits of Dialium angolense presages its food properties in this plant.
For ash (Table 5), the leaves of Dialium angolense have a value close to that of Protalaria retusa leaves : 7-8% (Alalade et al., 2019) but lower than that of Dialium angolense fruits (15.5 ± 0.4%). On the other hand, the ash content in Dialium angolense fruits is closer to that of Cassia tora fruits: 15,01± 0,03% ( Muhammad et al., 2018b) but slightly higher than that of Dialium guineense fruits: 12.5% (Besong et al., 2016). . Furthermore, not only that the fall in Na, K, Ca and Mg (Rani et al., 2015) and P (Ayoola et al., 2005), would be responsible for asthenia and dyspepsia but also the fall in vitamin A would favor the evolution of cerebral malaria (Benzecry et al., 2016). However, the intake of Na, K, P, Cu, Mn, Zn, vitamins A, B9, C and E, which can be obtained from the consumption of the leaves or fruits of Dialium angolense, can positively influence the outcome of a plasmodium infection provided that it has been shown during this study that the leaves and fruits of Dialium 342 angolense constitute a source of supply of these aforementioned nutrients. This observation completes the interest of the use of natural plant extracts in the treatment of pathologies in place of pure molecules because the extracts contain, in addition to the active principle, other compounds intervening at several levels and likely to contribute to stabilize the condition of the patient.

Conclusion:-
This study has presented the first data on the nutritional and anti-nutritional components of Dialium angolense leaves and fruits while estimating their contribution in managing the malaria disease. This information indicates that this plant is likely to provide an important dietary supplement of carbohydrates and proteins in addition to some mineral elements and vitamins, such as Sodium, Potassium, Magnesium, Iron, Zinc, Phosphorus and vitamins: A, B6, B9, C, essential for nutritional benefits, particularly in the case of malaria. It may be considered from this study that, the integration of this plant resource, underutilized until then, into Congolese eating habits to combat food insecurity and strengthen nutritional management against malaria.

Conflicts of interest:
The authors declare that they have not known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.