Oxidative stress mitigation, kinetics of carbohydrate-enzymes inhibition and cytotoxic effects of flavonoids-rich leaf extract of Gazania krebsiana (Less.): An in vitro evaluation

Objective: To investigate the free radical scavenging, antidiabetic, kinetics of enzyme inhibition and cytotoxic potentials of flavonoid-rich extract of Gazania krebsiana leaves using standard methods. Methods: Antioxidant activity of the flavonoids was investigated at scavenging free radicals such as 1,1-diphenyl-2-picryl hydrazyl, nitric oxide, hydroxyl radical, reducing capabilities, 2,2-azinobis (3-ethylbenzothiazoline-6) sulphonic acid as well as metal chelating capability at different concentrations (125-1 000 μg/mL) while the antidiabetic activity was evaluated via the inhibition and kinetics of carbohydrate digestive enzymes including α-amylase, α-glucosidase, sucrase and maltase. Brine shrimp lethality assay was also employed to examine the cytotoxic effects at various concentrations (125-2 000 μg/mL). Results: The study showed the best antioxidant activity in 2,2-azinobis (3-ethylbenzothiazoline-6) sulphonic acid, hydroxyl radical, nitric oxide and metal chelating with IC

Medicinal properties of Ocotea bullata stem bark extracts: phytochemical constituents, antioxidant and anti-inflammatory activity, cytotoxicity and inhibition of carbohydrate-metabolizing enzymes / 中西医结合学报

<p><b>OBJECTIVE</b>This study evaluates the phytochemical constituents, antioxidant and anti-inflammatory activity, cytotoxicity, and inhibitory activity against carbohydrate metabolism of extracts from Ocotea bullata stem bark.</p><p><b>METHODS</b>Hexane, ethyl acetate, methanol and water were used to extract the air-dried sample. The phytochemical investigation and antioxidant assays were carried out on the extracts using standard procedures. The antidiabetic and anti-inflammatory potentials were evaluated using α-amylase, α-glucosidase and 5-lipoxygenase enzymes respectively. Vero cells were employed to determine the cytotoxicity of the extracts.</p><p><b>RESULTS</b>The ethyl acetate extract showed higher phenolic contents (8.97 mg/g gallic acid) while methanol displayed higher flavonoid (36.06 mg/g quercetin) and flavonol (153.44 mg/g rutin) contents than other extracts. Hexane extract had the greatest capacity to scavenge 1,1-diphenyl-2-picryl-hydrazyl (0.19 mg/mL), hydroxyl (25.77 mg/mL) and 2,2-azino-bis(3-ethylbenzothiazoline)-6-sulfonic acid (0.07 mg/mL) radicals, while ethyl acetate extract exhibited stronger inhibition (P < 0.05) against superoxide anion (0.41 mg/mL) and ferric ion-reducing power (2.36 mg/mL) compared to other extracts and standards. Aqueous extract (27.02 mg/mL) exhibited strong metal-chelating activity (P < 0.05) compared to other extracts and gallic acid. The aqueous extract demonstrated the greatest inhibition of α-glucosidase (1.45 mg/mL) and α-amylase (2.43 mg/mL) compared to other extracts and acarbose. There were no significant differences (P < 0.05) in half-maximum inhibitory concentration (IC) values of all tested extracts and indomethacin in the inhibition of 5-lipoxygenase activity. The aqueous extract was nontoxic to Vero cells with an ICvalue of 0.38 mg/mL.</p><p><b>CONCLUSION</b>O. bullata stem bark contains active phytochemicals with diverse pharmacological potentials that could be beneficial in managing diabetes and inflammation.</p>

Chemical constituents, in vitro antimicrobial and cytotoxic potentials of the extracts from Macaranga barteri Mull-Arg

Objectives To investigate antimicrobial and cytotoxic potentials as well as chemical constituents of extracts from Macaranga barteri (M. barteri). Methods Antimicrobial activity was carried out using micro-dilution, cell culture and GC–MS methods were employed to determine the cytotoxicity and chemical constituents of the extracts respectively. Results Marked activity was observed in methanol (ME) fraction [MIC