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Some quality characteristics of seed oil extracted from Kumu; (Bombax aquaticum ) or "white peanut" harvest at Nkamba (DR Congo) were investigated. Herein, Kumu was chemically characterized regarding nutritional value, fatty acids, crude fat and chemicals indices. Furthermore, viscosity, absorptivity at 232 and 270 nm, color and DSC profil were evaluated. Data showed that the wild sample gave higher nutritional contribution related to a higher content of carbohydrates (54.74%±0.05), followed by fat (36.97±0.30%), proteins (5.68%±0.2), moisture (5.89%±0.12) and ash (2.61%±0.34). The physical properties of the oil extracts showed the state to be liquid at room temperature (25±1°C) and the color of the oil yellow clear (L* = 57.85; a* = 5.73; b* = 76.55). The dynamic viscosity of the oil was 12 mPa.sec. Among the chemical properties of the oil extracts, acid value (8.18±0.82 mg de NaOH/g), saponification number (162.31±0.15 mg KOH/100g of oil), iodine value (25, 59 m /100 g of oil) and peroxide value (6.86±0.31 meqO2/Kg) compared well with those of heated oils samples. The fatty acid composition consisted 54.89% palmitic acid (C16:0), 8.87% docosahexaenoic acid (C22:6ω3), 7.54% oleic acid (C18:1ω9), 6.09% Linoleic acid (C18:2), 3.19% Stearic acid (C18:0), 2.17% α-Linolenic acid (C18:3ω6), 0.89% Arachidonic acid (C20: 4). For a ''good nutritional quality'' with high health benefits, it also gave better PUFA/SFA and ω6/ω3 ratios. The thermal Behavior (DSC) of oil shows two peaks at +4.7 and +19.1°C for fusion and one peak at -4.3°C for crystallization. Absorptivity at 232 and 270 nm increased rapidly after heating.

The Nkamba nut (Ricinodendron africanum var Nkamba), named Kingoma-ngoma, a member of Euphorbiaceae yield 67% of oil when extracted with soxlhet using hexane as solvent. The crude oil is rich in C18:1 (19.48%); C18:2 (39.44%) and C18:3 (31.63%). The behavior of oil is investigated when heated at 100°C and/or stored 4 years at room temperature. The oxidation was appreciated by chemical indices or photospectrometrically (K232/270). The Totox value grew up from 5.33 in freshly extracted oils to 87.46 for aged oils. The level of hydroperoxides show a great amount of absorbance (0.857) for the primary byproducts in fresh oil heated. In the aged oils, there was a great level of ended byproducts up to 17.78. The fatty acid profile is modified with an amount of elaidic acid (0.0064 to 12.4%) and the strong decrease of the linolenic acid rate (31.63 to 1.07%). The thermogramm shows a peak of -27.1°C which is deplace to -15.1°C by progressive saturation of double bonds. Despite of natural antioxidants content, Nkamba nut oil is hardly oxidized in 4 years and then became unusual to human consumption.

Dacryodes edulis (safou) pulp oil has a high potential in Africa. But oil composition depends on fruit origin and ripening conditions. In the present study, the average safou oil extracted from raw fruits of mixed origin with those produced in the Guinea gulf are compared. The ratio of oil extracted by enzyme methods compared to the same extracted using solvents or press are reported. The level of enzyme extraction by Viscozym L was 42% while the solvent chloroform/methanol (2/1 v/v) gave 42.3% and the Soxhlet 47%. Oil extracted from fresh fruits had the same composition as that described in the Guinea gulf fruits and particularly showed the same PUFA content. Iodine, acidic, and peroxide values were low ranging to 79.6, 2.3 and 3.2, respectively, and fatty acid composition represented 50% saturated, 25% monounsaturated and 25% polyunsaturated. The thermal and rheological properties of safou pulp oil were studied showing a maximum melting point at 15 °C.

The economic development of Safou fruit shows good prospects in some African countries. The fruit contains nearly 50% oil of high nutritional value and classic oil extraction could provide new markets for its exploitation. Iodine value, peroxide value and the content of thiobarbituric reactive species were measured over a period of 2 months, at four temperatures from 4 to 50 °C, to evaluate oxidation of free and maltodextrin-encapsulated safou oil. The present study showed the good stability of the native oil at low temperature and the good protection provided by a 6DE maltodextrin matrix against oxidation, at 50 °C. Freeze-dried particles were more efficient against oil oxidation than spray-dried particles.

It has been shown that boric acid has well-defined biological effects such as stimulation of wound healing in vivo, release of growth factors and cytokines, and increase of the extracellular matrice turnover. We examined its action at the molecular level, using cell-free systems of transcription (isolated placenta nuclei) and translation (wheat germ extract). We found that 10 mM boric acid greatly increased RNA synthesis, measured by absorbance at 260 nm (x 6.4) or by [3H]-UTP uptake (x 11). Full-length functional mRNA was produced because proteins of 14-80 kDa were translated. Among these proteins, factors involved in angiogenesis and, subsequently, in wound healing (VEGF and TGFbeta) were identified by slot blot, whereas growth factors such as FGF1 and TNFalpha were not detected. These results demonstrate that boron may contribute to biological cell activities at both the transcription and translation levels. However, the mechanism of action is still not known.

Boric acid was not mitogenic for human fibroblasts and it did not change cell viability until 0.5% (w/v). Boric acid treatment affected the metabolism of human dermal fibroblasts in culture, decreasing the synthesis of extracellular matrix macromolecules such as proteoglycans, collagen, and total proteins. It also increased the release of these molecules into the culture medium. The principal proteins secreted into the medium after boric acid treatment had molecular masses of 90, 70, 58, 49, and 43 kDa and faint bands were detected by electrophoresis between 14 and 30 kDa. hsp 70 and TNF alpha were detected among the secreted proteins by immunoblotting, and the amount of TNF alpha released was quantified by radioimmunoassay. Total mRNA levels were higher after boric acid treatment and peaked after 6 h of treatment. TNF alpha mRNA was undetectable in unstimulated fibroblasts and two TNF alpha mRNA bands were detected after stimulation: immature mRNA (4.8 kb) and mature TNF alpha mRNA (1.9 kb). Thus, the effects of boric acid observed in wound repair in vivo may be due to TNF alpha synthesis and secretion.

The recently cloned cytotoxic lymphocyte maturation factor [CLMF] also called NK cell stimulatory factor [NKSF] or interleukin-12 [IL-12] has been described as a growth factor for mature lymphoid cells. The present study investigated whether purified recombinant human IL-12 could stimulate CFU colony growth. Source of progenitor cells were peripheral blood cells depleted of adherent, CD2- and CD56-positive cells. RhIL-12 was investigated either alone or in combination with rhIL-3, rhIL-6 and rhGM-CSF. RhIL-12 alone did not support colony formation of myeloid or erythroid progenitors. RhIL-12 in combination with rhIL-3 increased the numbers of BFU-E and CFU-GM. No synergism or additive effect was seen with the combination of rhIL-12 and rhGM-CSF or rhIL-12 and rhIL-6. An additive increase in the number of granulocytic colonies was observed when rhIL-3, rhIL-6 and rhGM-CSF were used together with rhIL-12. Our result therefore suggest that, in addition to being a potent lymphopoietic stimulator, IL-12 acts synergistically with IL-3 in enhancing the sensitivity of hemopoietic progenitors to IL-3.

To gain additional informations on the role played by Natural Killer cells (NK) in the differentiation of human hematopoietic precursors, we have studied the effect of NK-cell depletion on the in vitro proliferation of hematopoietic cells. NK cells were depleted from blood mononuclear cells by FACS using anti CD3 and anti CD56 monoclonal antibodies. Depletion of NK cells suppressed CFU-GM up to 69% (P < 0,01), while no significant effect on either BFU-E and CFU-Mix growth was observed. To define the threshold of CD56+ cells required to support CFU-GM formation, NK cells were added to NK-depleted cells in a titrated fashion. Enhancement of CFU-GM colony growth was observed at NK/NK - depleted cells ratio of 0.15/1. A dose dependent suppression of CFU growth was observed at ratios ranging from 0.25/1 to 0.5/1. Addition of neutralizing antibodies against IL3 and GM-CSF abrogate the stimulating effect of NK cells. Our results suggest that cells with LGL morphology and NK markers play an important role in differentiation of myeloid precursors and exert a moderate influence on erythroid progenitors. The modulatory effect on hematopietic progenitors depend on the number of NK cells present in the mixed culture. © 1994 Wiley-Liss, Inc.