Browsing by Author "Musa Alfanla Kamaldeen"

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    Effect of Time of Harvest on the Chemical Composition and Antioxidant Potential of Leaf Essential Oil of Syzygium guineense Growing in North Central Nigeria (Willd.) Dc. Var.
    (J. Mex. Chem. Soc., 2024-02-16) Musa Alfanla Kamaldeen; Lamidi Ajao Usman; Ridwan Olanrewaju Ismaeel
    The use of synthetic antioxidants to ameliorate oxidative stress goes with side effects. Some plants are known to be sources of natural antioxidants and, hence, could be used as alternatives to synthetic antioxidants without side effects. Meanwhile, the presence of the phytochemicals that exhibit antioxidant activity in plants depends on environmental conditions that vary with the time of harvest of plant materials. This study, therefore, investigated the effect of time of harvest on the chemical composition and antioxidant potential of leaf essential oil of Syzygium guineense native to North central Nigeria. To accomplish these, pulverized (500 g) leaves of S. guineense harvested in the morning and afternoon were separately hydrodistilled and yielded 0.25 ± 0.002 % (w/w) and 0.27 ± 0.003 % (w/w) of essential oils. Characterization of the oils using GC-MS revealed the presence of twenty-two and twenty-three compounds in the oils from morning and afternoon harvests. The most abundant compound in the oils was β-bergamotene (30.1 % and 27.3 %). D-limonene (2.9 % and 5.6 %), β-ocimene (4.2 % and 10.2 %), α-santalene (7.4 % and 7.7 %), α-cedrene (8.6 % and 9.0 %), β-farnesene (9.1 % and 10.2 %) and calamenene (7.1 % and 5.2 %) were detected in significant quantities in the oils. DPPH radial scavenging assay was used to evaluate the antioxidant activity of the oils with butylated hydroxyl toluene (BHT) as standard. The oils exhibited antioxidant activity with IC50 of 41.92μg/mL and 33.12 μg/mL for the oils from morning and afternoon harvests. Although the oils exhibited lower antioxidant activity than the standard (IC50 of 28.63 μg/mL), but the oils could be used to ameliorate oxidative stress after clinical trials.
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    Isotherms, kinetics and thermodynamic sorption of paranitroaniline on Cocos nucifera shell activated carbon@TiO2 composite
    (Vietnam J. Chem., 2024-10-14) Samsudeen Olanrewaju Azeez; Muhammed Hatim Garuba; Ismaila Olalekan Saheed; Akeem Adebayo Jimoh; Musa Alfanla Kamaldeen; Damilola Tope Ogundele
    A comparative study was conducted on the adsorption capacity of Cocos nucifera shell-activated carbon (CNSA) and Cocos nucifera shell-activated carbon@TiO2 composite (CNSA-TiO2) for para-nitroaniline in an aqueous medium. The CNSA was carbonized at 500 ◦C and activated with 1 M HNO3 while the CNSA-TiO2 composite was prepared by wet impregnation method. The prepared adsorbents were characterized through Brunauer–Emmett–Teller (BET), energy dispersive X-ray (EDX) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM). The BET-surface area of CNSA-TiO2 (748.96 m2/g) was established to be larger than CNSA (574.21 m2/g), however both materials are mesoporous. The effects of initial p-NA concentration, pH, adsorbent dosage, contact time, and temperature, were explored for both adsorbents. The results showed that the adsorption operating parameters influenced the adsorption process except for temperature, with maximum adsorption of 38.26 and 38.36 mg/g for CNSA and CNSA-TiO2, respectively. Freundlich, Langmuir, Temkin, and DubininRadushkevich isotherms were tested on the adsorption data, and the adsorption process of both adsorbents followed the Freundlich isotherm model (R2 > 0.988). Among the kinetic models studied, the pseudo-second-order model (R2 = 1) best described both processes. The thermodynamic parameters such as ∆G◦, ∆H◦ and ∆S ◦ were calculated. The process was exothermic, spontaneous and feasible.