Maize husk, an abundant agricultural waste was used to prepare a biosorbent for the biosorption of Mn(II) and Pb(II) ions from aqueous solution in a batch process. Equilibrium and kinetics of biosorption of the metals ions were studied at 25°C. The adsorbtion data were treated with common kinetic and isotherm models. The equilibrium data fitted well with Langmuir isotherm with maximum capacity of 8.52 and 7.38 mg g-1 for Mn(II) and Pb(II), respectively on raw biomass (UTCS). The capacity of 9.00 and 9.33 mg g-1 was observed for Mn(II) and Pb(II), respectively on acid modified biomass (ATCS). The study also revealed that the sorption process in both cases depend on biomass dosage, temperature, pH and initial metal ion concentration, respectively. The calculated thermodynamic parameters (DG o , DH o and DS o) showed that the biosorption of the metal ions onto maize husk is feasible, spontaneous and exothermic in nature.

Background:Copper is one of the heavy metals whose presence in aquatic environment in higher concentration poses a major threat to the environment. This is due to their toxic effects on the plants, animals and human health. Biosorption an innovative biotechnological technique with superior advantages was used for the remediation of Cu 2+ from aqueous solution in this study.Methods: Biosorbent was prepared from raw (RAWB) and oxalic acid modified (OAMB) Saccharum officinarum. They were characterized by scanning electron microscopy (SEM/EDAX), fourier transform infrared (FTIR), and X-ray diffraction (XRD) for surface morphological study. Experimental data obtained from batch equilibrium studies were subjected to two-parameters [Freundlich, Langmuir, Tempkin and Dubinin-Radushkevich (D-R)] and three-parameter [Redlich-Peterson (R-P), Sips, Hill and Toth] isotherm models. Kinetic data were analysed with pseudo first-order, pseudo second-order, Elovich and Avrami kinetic models. Results:The results of proximate analysis and characterization show that the oxalic acid modification affected the biosorbents content, surface modifications and the functional groups present. The experimental data from the equilibrium studies were best fitted to the isotherms with R 2 >0.9 for the OAMB and RAWB. The adsorption energies (E) from the D-R isotherms were found to be 0.36 and 0.06 kJ/mol for OAMB and RAWB respectively, which is indication of physisorption favoured processes. Pseudo second-order model best fitted the data with a coefficient of determination (R 2 ) of above 0.998 with an average relative and hybrid errors lower than 5 %. Intraparticulate diffusion model analysis showed that the adsorption process develops in two stages as rapid and slow phase. Changes in standard free energy (∆G°), enthalpy (∆H°) and entropy (∆S°) for the biosorption processes were estimated using the thermodynamic equilibrium model. The calculated thermodynamics parameters indicated that the process is spontaneous and endothermic in nature. Conclusions:This study revealed the feasibility of Cu 2+ removal through biosorption processes using S. officinarum biomass as biosorbent. The improved surface morphology for increase biosorption by oxalic acid modification is also favourable. The biosorption process for the removal of the Cu 2+ is pH dependent as the efficiency increased from 36.4 to 65.3 % for raw biomass while the OAMB has increase efficiency from 57.5 to 88.6 as the pH increases from 2 to 6.

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As a follow-up to earlier reported works on the phytochemical study of some isolated bioactive compounds from the root and bark of Entandrophragma congoënse as potent anti-plasmodium drugs (Happi et. al.2005), some of the isolated compounds were tested in vitro for antiplasmodial and cytotoxicity but no insight was given into the binding affinities of these compounds, the ADMET (Absorption, Distribution, Metabolism, Excretion and Toxicity), drug-likeness studies as well as molecular dynamics simulation of some of the isolates. Hence, a total of 21 compounds including 19 isolates and 2 standard drugs were computationally studied for antimalarial activity against the target receptor with Protein Data Bank code (PDB code: 5TBO), but only 4 of the isolated compounds (L1, L2, L4 and L15) showed promise potent hits against Plasmodium. The results of molecular docking, ADMET studies and molecular dynamics simulations reveal that compound L15, when isolated, can alone, or together with other qualified compounds such as L1, L2 and L4 provide a better inhibition rating compared to Chloroquine® (L21) the FDA-approved drug for the treatment of malaria.

The phytochemical investigations of the methanol extract of Zanthoxylum gilletii bark led to the isolation of thirteen compounds identified as two alkaloids including one acridone 5-hydroxynoracronycine (1) and one benzo [c] phenanthridine decarine (2), three lignans trans- and cis-fagaramide (3 and 4) and sesamin (5), two coumarins scoparone (6) and scopoletin (7), three pentacyclic triterpenoids fridelin (8), lupeol (9) and erythrodiol-3-O-palmitate (10), one phenolic compound vanillic acid (11) as well as two common steroids stigmasterol (12), and its derivative stigmasterol-3-O-β-D-glucopyranoside (13). The structures of all the isolated compounds were elucidated by means of their spectroscopic and spectrometric data (1D, 2D-NMR, MS) as well as the comparison of these data with those reported in the literature. Except for compounds 9 and 11–13, all the other isolated compounds are reported for the first time from Z. gilletii but have been already obtained from other Zanthoxylum species and in the Rutaceae family. Compounds 1, 3–5, and 9 were tested in vitro for their antiplasmodial potencies against Plasmodium falciparum 3D7, and the results revealed that all the tested compounds displayed an inhibition between 51.89% and 54.69% while only the mixture of 3 + 4 gave an IC50 lower than 10 000 nM (IC50 = 1333 nM). Furthermore, all the compounds have been evaluated in silico for their ability to inhibit the Plasmodium falciparum dihydroorotate dehydrogenase 5TBO. Sesamin (5) showed the greatest affinity to the antiplasmodium receptor than artemether® and chloroquine®. Further recorded data from their ADMET study, as well as their chemotaxonomy, are also discussed herein. The present study provides further information to enrich the chemistry of Z. gilletii and its qualification as an important source for good candidates in new antiplasmodial drug development.