Browsing by Subject "antioxidant"

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    Antimycobacterial, Cytotoxic, and Antioxidant Activities of Abietane Diterpenoids Isolated from Plectranthus madagascariensis
    (2021-01-19) Ndjoubi, Kadidiatou O; Sharma, Rajan; Badmus, Jelili A; Jacobs, Ayesha; Jordaan, Audrey; Marnewick, Jeanine; Warner, Digby F; Hussein, Ahmed A
    Medicinal plants of the Plectranthus genus (Lamiaceae) are well known for their ethnomedicinal applications. Plectranthus madagascariensis, which is native to South Africa, is traditionally used in the treatment of respiratory conditions, scabies, and cutaneous wounds. The phytochemical studies of P. madagascariensis led to the isolation of five known royleanone abietanes, namely, 6β,7α-dihydroxyroyleanone (1), 7α-acetoxy-6β-hydroxyroyleanone (2), horminone (3), coleon U quinone (4), and carnosolon (5). The relative configuration of compound 2 was established by X-ray analysis. Compounds 1–4 showed antimycobacterial activity (Minimum inhibitory concentration for 90% inhibition, MIC90 = 5.61–179.60 μM) against Mycobacterium tuberculosis H37Rv. Compound 4 and 5 showed comparable toxicity (Concentration for 50% inhibition, IC50 98.49 μM and 79.77 μM) to tamoxifen (IC50 22.00 μg/mL) against HaCaT cells. Compounds 1–5 showed antioxidant activity through single-electron transfer (SET) and/or hydrogen-atom transfer (HAT) with compound 5 being the most active antioxidant agent. Compounds 3 and 5 were isolated for the first time from P. madagascariensis. The observed results suggest P. madagascariensis as an important ethnomedicinal plant and as a promising source of diterpenoids with potential use in the treatment of tuberculosis and psoriasis.
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    Effect of selenium on cadmium-induced oxidative stress and esterase activity in rat organs
    (2013) Dzobo, Kevin; Naik, Yogeshkumar V
    Metal toxicity is a threat mainly in the industrialised world where industry discharges many toxic metals into the environment. We investigated the effects of two metals - cadmium and selenium - on the cytosolic antioxidant enzymes and esterases in the liver, kidneys and testes of rats. Male Sprague-Dawley rats( N =28) were divided equally into four groups: control, cadmium, selenium and cadmium/selenium. Salts of the metals were administered intraperitoneally for 15 days. In the liver, cadmium treatment (1.67 mg/kg per day) resulted in a decrease in catalase activity and an increase superoxide dismutase (SOD) activity. Selenium treatment (0.23 mg/kg per day) resulted in increases in glutathione s-transferase, catalase and DT-diaphorase activities. Treatment with both cadmium and selenium resulted in an increase in glutathione peroxidase (GPx) activity. Esterase activities were significantly lower in the presence of cadmium. In the kidney, cadmium treatment caused a decrease in catalase, DT-diaphorase, and SOD activities and selenium supplementation reversed the cadmium-induced decrease in these enzyme activities. Selenium treatment increased catalase and SOD activities in the kidney. In the testis, cadmium treatment decreased GPx and SOD activities, but at the same time increased catalase and DT-diaphorase activities. Esterase activities increased in the presence of selenium in both the kidney and testis. These results suggest that selenium might be toxic to the liver while at the same time play a protective role against cadmium-induced oxidative stress and toxicity in the kidney and testis.