In vitro antioxidant properties and inhibitory effect of extracts and fractions of Plectranthus glandulosus leaves on copper sulfate (CuSO4)-induced oxidation in human low-density lipoprotein

Abstract

Oxidation of LDL has been suggested to be an initial step in the development of atherosclerosis. This research work deals with the evaluation of antioxidant potential of Plectranthus glandulosus leaves extracts and fractions as well as its protective effects against human LDL oxidation. A preliminary quantitative phytochemical screening was carried out. Antioxidant potential was evaluated employing in vitro hydrogen peroxide, nitric oxide scavenging assays and TAOC test. The human LDL oxidation induced by CuSO4 inhibition test was also performed. Plectranthus glandulosus leaves exhibited the presence of 18.3% of saponines, 25.6% of terpenoids and 36.2% of flavonoids. EAF exhibited highest hydrogen peroxide and nitric oxide scavenger activity (IC50 13.63µg/ml and 24.59 µg/ml respectively). Ascorbic acid exhibited an IC50 value of 15.39µg/ml in hydrogen peroxide assay and 22.96 µg/ml in nitric oxide scavenging activity. EAF exhibited a higher TAOC (optical density 0.186±0.00) than that of ascorbic acid (0.162±0.001) at the concentration of 25µg/ml while at 200µg/ml N-BUTF exhibited a higher optical density (1.261±0.001) than that of ascorbic acid (1.065±0.001). EAF lengthened the lag time of the CD formation up to 150mins at the concentration 1mg/ml. TBARS formation inhibition at the concentration 0.5mg/ml, were no significant different between n-butanol (68.55%) ethyl acetate fraction (68.21%) and quercetin 67.69%). Plectranthus glandulosus is a promising prospect as an anti-atherosclerotic agent and needs a detailed study to establish the same.
 Key words: Plecthrantus glandulosus; oxidation; LDL; atherosclerosis, antioxidant.

In Vitro Antilipidic and Antithrombotic Activities of Plectranthus glandulosus (Lamiaceae) Leaves Extracts and Fractions

“…Flavonoids present in extracts, and fractions might be responsible for the thrombolytic activity observed in this study [22]. Also, alkaloids, tannins, and saponins, which were identified in the plant in previous studies [28][29][30][31], are involved in thrombolytic activities [23].…”

“…The interaction of phenolic compounds with cholesterol esterase is due to the presence of potent cholesterol esterase inhibitory sites, especially the interaction with the catalytic triad and oxyanion hole residues [ 49 ]. Our previous study also reported that hydroethanolic extract and ethyl acetate fraction have antioxidant properties [ 28 , 29 ], and it is shown that a positive correlation exists between phenolic compounds, antioxidant activity of plant extracts, and digestive enzyme inhibitory activity [ 50 , 51 ].…”

“…However, earlier scientific data reported its implication in the treatment of influenza, cough, chest complaints, and as food preservatives [25]. The antinociceptive, anti-inflammatory, and antioxidant activities of the plant [26][27][28][29] as well as the inhibition of LDL oxidation have been reported [29]. Phytochemical examination of P. glandulosus revealed the presence of secondary metabolites such as alkaloids, flavonoids, saponins, terpenoids, steroids, tannins, and glucosides [28][29][30][31].…”

“…The antinociceptive, anti-inflammatory, and antioxidant activities of the plant [26][27][28][29] as well as the inhibition of LDL oxidation have been reported [29]. Phytochemical examination of P. glandulosus revealed the presence of secondary metabolites such as alkaloids, flavonoids, saponins, terpenoids, steroids, tannins, and glucosides [28][29][30][31]. Further phytochemical studies isolated a methoxylated flavonoid derivative plectranmicin, a monoterpene derivative plectranmicinol, and seven known compounds (5-hydroxy-3,7,2 ′ ,4 ′ -tetramethoxyflavone, 5,7-dihydroxy-3,2 ′ ,4 ′ -trimethoxyflavone, 7-hydroxy-5,6,4 ′ -trimethoxyflavonen, 3-epi-betulinic acid, 3-O-β-D-glucopyranosyl stigmasterol, β-sitosterol, and 4-epi-fridelin) [32].…”

Pro-apoptotic property of phytocompounds from Naringi crenulata in HER2+ breast cancer cells in vitro

“…The SK-BR3 cells (30,000-50,000 cells/well) were plated to a 24 well plate and incubated for 24 h in McCoy's 5A growth medium. After incubation, the plate was gently rinsed with PBS and treated with 24.59 lg/mL of extracted compound sample in serum-free McCoy's 5A medium based on previous research on other extracts [23]. Again, the plate was kept for incubation at a temperature of about 37 C in a humidified 5% CO 2 incubator for about 24 h. The mitochondrial membrane potential measurement for the treated and control cells was done according to the manufacturer's instruction.…”