The present study aims to make an evaluation of some secondary metabolites and determination of the antioxidant potential of P. aquilinum plant extracts obtained by means of a simple and rapid TLC method. The latter revealed the presence of terpenes, sterols, steroids, flavonoids, polyphenols, saponins, sugars and amino acids. The evaluation of the potential antioxidant was assessed on phenolic and flavonoid compounds. These compounds' dosages revealed different levels, but the highest antioxidant activity was found in the hydro-ethanol extract followed by the aqueous extract. Among the two families of evaluated antioxidants, phenolic compounds were found to be higher in the hydroethanolic extract (75.18 mgEAG/gM S ), followed by the aqueous extract (66.78 mgEAG/gM S ) and lower in the ethanolic extract (12.39 mgEAG/gM S ). Whereas flavonoids, less significantly elevated, showed values of 2.58 mgECa/gM S for the hydro-ethanolic extract, 2.24 mgECa/gM S for the aqueous extract and 1.58 mgECa/gM S for the ethanolic extract. However, the antiradical activity was also evaluated. Contrary to the antioxidant activity, the most important antiradical activity was observed on the hydroethanolic extract with a rate of 3.61 mg/mL, then a weak activity on the aqueous and ethanolic extracts respectively 6.18 mg/mL and 15.81 mg/mL, then less important on the aqueous

The aim of this study is to evaluate the purifying ability of 3 parallel planted filters (PF1, PF2 and PF3) composed of three plants (Phragmites australis (Cav) Trin ex Steud, Typha latifolia L., Cyperus papyrus L.) on leachates from a landfill of industrial waste in Pointe-Noire (Republic of Congo). This landfill site includes a technical landfill for ordinary industrial waste (OIW) and a technical landfill for hazardous and soiled industrial waste (SIW). In order to assess purifying ability, we sampled 14 samples over 8 weeks, with 7 samples of the raw leachates from the technical landfill center, and 7 samples of leachates cleaned after passing through the tryptic vegetable filter. The physico-chemical analyzes made it possible to determine the following parameters: TOC, COD, NO3 -,PO42-, Ni, Cd, CrVI, Zn, Cu and Pb. The results showed a significant decrease in organic pollution with abatement rates in TOC and COD greater than 90%. The average removal efficiency is respectively 45.97% for nitrates and 40.2% for phosphates. The abatement rates for heavy metals range from 41.2% to 60.9% for nickel, from 52.2% to 68.5 % for cadmium, from 49% to 71.7% for chromium VI, from 59% to 74.6% for zinc, from 50.9 % to 65 % for copper and from 61.4% to 75.1% for lead. However, additional analyzes are needed to confirm the hypperaccumulator nature of these plant filters in particular absorption isotherms and kinetics of extraction of heavy metals of Phragmites australis (Cav) Trin ex Steud, Typha latifolia L., Cyperus papyrus L.)

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26www.ijeas.org  Abstract-The hydrodistillation of the dry leaves of Cymbopogon citratus (DC) Stapf and Cymbopogon nardus (L.) Rendle harvested in the southern part of Brazzaville (Makelékelé) yields yellow essential oils with respective yields of 1,54% and 2.34%. These were subjected to physico-chemical analyzes and then characterized by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The physical and chemical properties evaluated were the refractive index and the acid number, the respective values of which are (1.4887 and 0.224) for the essential oil of Cymbopogon citratus and (1.4742 and 0.280) for the essential oil of Cymbopogon nardus chromatographic and spectrometric analyzes revealed that the essential oil of Cymbopogon citratus is predominantly monoterpene (95.87%) with a preponderance of oxygenated monoterpenes occupying a high level of (90.24%). The hydrocarbon monoterpenes represent (5.63%), the hydrocarbon sesquiterpenes occupy a very small proportion of (0.07%). The essential oil of Cymbopogon nardus is rich in monoterpenes (77.85%) with a predominance of oxygenated monoterpenes (75.89%). The hydrocarbon monoterpenes are very low (1.96%). Oxygenated sesquiterpenes constitute (12.39%), while hydrocarbon sesquiterpenes are poorly represented (3.46%). Geranial (51.99%) and nereral (32.94%) two geometric isomers, carbonyl compounds forming citral are the major components of the essential oil of Cymbopogon citratus while citronellal (32.53 %) is the major carbonyl compound of the essential oil of Cymbopogon nardus, followed by geraniol (26.84%) and citronellol (10.98%). Thanks to the low refractive index, presence and important proportions of geranial (51.99%), neral (32.94%) and citronellal (32.53%), these essential oils could constitute a reservoir of exploitation carbonyl compounds required for the agri-food, cosmetic, pharmaceutical, and chemical and perfume industries. Résumé : L'hydrodistillation des feuilles sèches deCymbopogon citratus (DC) Stapf et Cymbopogon nardus (L.) Rendle récoltées dans la partie sud de Brazzaville (Makelékelé) fournit des huiles essentielles de couleur jaune avec des rendements respectifs s'élevant à 1,54% et 2,34%. Celles-ci ont été soumises aux analyses physico-chimiques puis caractérisées Composés carbonylés majeurs et indices physico-chimiques des huiles essentielles de deux espèces du genre Cymbopogon (Poaceae) du Congo-Brazzaville 27 www.ijeas.org Composés carbonylés majeurs et indices physico-chimiques des huiles essentielles de deux espèces du genre Cymbopogon (Poaceae) du Congo-Brazzaville 33 www.ijeas.org