Tropical Leafy Vegetables as Valuable Sources of Carotenoids and Phenolics

Leafy vegetables play an important role as essential components of diet for rural populations in tropical Africa. This study was undertaken to provide a more comprehensive characterization of carotenoids and phenolics in these neglected plant foods.For this,12 leafy vegetables widely consumed in Côte d’Ivoire were selected, washed and oven-dried (50°C/3 days) before High-Performance Liquid Chromatography (HPLC) analysis of carotenoids and phenolics compounds.Carotenoids contents were significantly different (p ? 0.05) with lutein (43.68 ± 4.89 –513.91 ± 5.68 ?g/g dw) and all trans-?-carotene (22.62 ± 1.54 –222.61 ± 5.63 ?g/g dw) as major constituents. The calculated retinol activity equivalent (RAE) of ?-carotene-rich leafy vegetables in this study ranged between 1.54 and 2.52 mg/100g. The values of total phenolics ranged from 179.66 ± 11.33 mg/100g dw in Corchorus olitoriusto 436.48 ± 1.73 mg/100g dw in Abelmoschus esculentus.Three (3) flavonoids: quercetin (0.79 –8.36 ?g/g dw), catechin (0.39 –5.65 ?g/g dw) and kaempferol (0.76 –29.11 ?g/g dw) were quantified in the selected leafy vegetables.Chlorogenic acid (0.94 –17.01 ?g/g dw) was the most quantified phenolic acid in the leaves. Antioxidant activity evaluation of the leaves showed that 2,2-Diphenyl-1-Picrylhydrazyl (DPPH) radical scavenging activity ranged between 19.63 and 65% with Solanum melongenashowing the highest value (65%). For 2,2’-Azino-Bis(3-ethylbenzothiazoline-6-sulphonic acid) or ABTS scavenging activity, Myrianthus arboreusrecorded the highest value (76.66%) compared to other leaves. All these results suggest that the studied leafy vegetables are potential sources of carotenoids and phenolics and their consumption in sufficient amount may contribute to human health improvement.

Purification and characterization of two acid phosphatases from germinating peanut [arachis hypogaea] seed

The maximum acid phosphatasic activity was detected in peanut seed at the 5th day of germination. At least, two acid phosphatases were purified by successive chromatography separations on DEAE-Sepharose CL-6B, CM-Sepharose CL-6B, Sephacryl S-100 HR, and Phenyl-Sepharose HP to apparent homogeneity from five days old cotyledon of peanut after germination. These isoenzymes, designated peanut cotyledon acid phosphatase 1 and 2 [PCAP 1 and PCAP 2], had native molecular weights of approximately 27.5 and 24 kDa by gel permeation, respectively. SDS-PAGE [Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis] of PCAP 1 and PCAP 2 resolved a single protein band [each] that migrated to approximately 27 and 29 kDa, respectively. Thus, these acid phosphatases likely function as a monomer. The two isoenzymes had a similar optimum temperature [55°C], two closely optima pH [5.6 and 5.0], and appeared to be stable in the presence of some detergents such as Triton X-100, Nonidet P-40, Taurocholic acid sodium salt, Polyoxyethylene-9-lauryl ether as well as Mg2[+], Sr2[+], Fe3[+] and Ba2[+]. Substrate specificity indicated that PCAP 1 and PCAP 2 hydrolyzed a broad range of phosphorylated substrates. However, natural substrates such as ADP, ATP and phenylphosphate had the highest rate of hydrolysis for the two isoenzymes