DEPARTMENT OF SCIENCE LABORTATORY TECHNOLOGY

This study investigates and compares the antioxidant, phytochemical, and antimicrobial activities of aqueous and ethanolic extracts of Cymbopogon citratus (lemongrass) leaves. Fresh leaves of C. citratus were collected, shade-dried, pulverized, and extracted using distilled water and 70% ethanol. Qualitative and quantitative phytochemical screenings were conducted to determine the presence and levels of phenolic compounds, flavonoids, tannins, saponins, alkaloids, glycosides, and terpenoids. The antioxidant activities were assessed using DPPH,and FRAP assays, while antimicrobial activities were evaluated using agar well diffusion and broth microdilution methods against Staphylococcus aureus, Aspergillus Niger, Klebsiella pneumoniae, seudomonasaeruginosa, and Candida albicans. Preliminary findings suggest that ethanolic extracts of C. citratus contain higher concentrations of total phenolics and flavonoids compared to aqueous extracts. Consequently, ethanolic extracts demonstrated stronger antioxidant activities and broader antimicrobial spectra. These results highlight the influence of extraction solvent
polarity on phytochemical yield and biological activity. The findings of this study may contribute to the development of natural antioxidant and antimicrobial agents derived from lemongrass for use in pharmaceuticals, cosmetics, and food preservation.

Cadmium (Cd) is a pervasive environmental toxicant known to induce hepatotoxicity through oxidative stress. This study investigated the protective effect of a hydroethanolic extract of Citrullus lanatus (watermelon) rind against cadmium-induced liver damage in Wistar rats. Twenty five rats were divided into five groups: control, negative control (CdCl₂ only), Vitamin C, and two groups receiving C. lanatus extract (250 mg/kg and 500 mg/kg). After 60 days, biochemical liver markers were analyzed. The negative control group showed elevated levels of AST, ALT, and total bilirubin, indicating hepatocellular injury. In contrast, treatment with the C. lanatus extract, particularly at 500 mg/kg, significantly ameliorated these alterations, bringing the enzyme and bilirubin levels closer to those of the control and Vitamin C groups. The extract also counteracted the growth-suppressive effect of cadmium, with treated groups showing significantly higher body weight gain. There were no significant changes in liver cadmium concentration or liver to body weight ratio across groups. This can imply that the hydroethanolic extract of C. lanatus rind possesses potent hepatoprotective properties against cadmium toxicity, likely mediated by its antioxidant phytoconstituents, which stabilize hepatocyte membranes and improve metabolic function without altering cadmium accumulation.

The escalating ecological threats posed by invasive aquatic plants and the pressing need for sustainable bioenergy sources have driven the investigation of viable lignocellulosic feedstocks. This research centers on the thermochemical pretreatment of water hyacinth (Eichhornia crassipes) to improve biodegradability and biogas production. Water hyacinth, recognized for its high lignin content that prolongs microbial digestion periods (30–60 days), was treated with sodium hydroxide (NaOH) under varying conditions of temperature, dosage and reaction. Response Surface Methodology (RSM) via Design-Expert software was utilized to optimize the pretreatment variables and assess their impact on degradation efficiency. The compositional analysis of raw water hyacinth indicated a moisture content of 70.17%, ash content of 19.94%, crude fiber of 0.4932%, and volatile solids of 9.88%, underscoring its suitability as a biogas substrate. The thermochemical pretreatment markedly boosted organic matter solubilization, evidenced by soluble chemical oxygen demand (sCOD) range of 36,600 mg/L and degree of degradation (%DD) reaching up to 91.05%, though RSM analysis showed no significant factor influences (mean %DD = 88.55%), implying a recalcitrance-induced plateau. The optimal conditions for the pretreatment were identified at temperatures of 80°C, 30ml NaOH dosage, and 30 minutes reaction time, yielding consistent improvements in solubilization. These results illustrate that thermochemical pretreatment effectively overcomes biomass recalcitrance in water hyacinth, enhancing digestibility and prospective biogas output.