Phytochemical Screening, Antioxidant, Anti-inflammatory, and Glucose Utilization Activities of Three South African Plants Used Traditionally to Treat Diseases

Abstract

Medicinal plants are important in the treatment of human diseases. The medicinal properties of plants are attributed to the presence of secondary plant metabolites. Polyphenols, particularly fl avonoids, are phytochemicals that possess antioxidant and anti-infl ammatory activity, and modulate pathways involved in obesity and glucose metabolism. In folk medicine, a single plant may be used to treat various diseases owing to the presence of phytochemical varieties in plants. In this study, the acetone leaf extracts of Curtisia dentata, Pittosporum viridifl orum, and Portulacaria afra were investigated for total polyphenol and total fl avonoid content as well as for anti-infl ammatory, antioxidant, and glucose utilization activities by using standard methods. The C. dentata extract exhibited the highest polyphenols (125.12  2.18 mg/g GAE) and fl avonoids (27.69  4.98 mg/g QE). The P. viridifl orum extract exhibited the strongest DPPH radical antioxidant activity (IC 50 value 5 12.94  1.09 µg/ml) and anti-infl ammatory activity by inhibiting 5-lipoxygenase activity (IC 50 value 5 46.50  4.54 µg/ml). All extracts enhanced dose-dependent glucose utilization activity of muscle cells and adipocytes. P. viridifl orum enhanced the highest glucose utilization of C2C12 muscle cells (67.34  0.51%), while C. dentata enhanced the highest glucose utilization of 3T3-L1 adipocytes (63.72  0.48%) at the highest concentration of 500 µg/ml, with no signifi cant difference (p  0.05). Polyphenols may be responsible for the observed 3T3-L1 cells glucose utilization activity of C. dentata. However, the polyphenols alone may not be responsible for the antioxidant, anti-infl ammatory, and C2C12 cells glucose utilization activity of P. viridifl orum. To our knowledge, this is the fi rst study to demonstrate the glucose utilization potential of the species of medicinal plants.

Nutritional Value and Antimicrobial Activity of Pittosporum angustifolium (Gumby Gumby), an Australian Indigenous Plant

“…3-fold more (p < 0.05) total phenolics than the QLD samples (Table 4). The results of the present study are similar to the reported TPC in leaves and twigs of other species belonging to the Pittosporaceae family, ranging from 2600 to 4090 mg GAE/100 g DW [42][43][44][45]. However, compared to…”

“…3-fold more (p < 0.05) total phenolics than the QLD samples ( Table 4). The results of the present study are similar to the reported TPC in leaves and twigs of other species belonging to the Pittosporaceae family, ranging from 2600 to 4090 mg GAE/100 g DW [42][43][44][45]. However, compared to green tea leaf powder, a popular source of polyphenols, the TPC in the studied P. angustifolium samples was lower (730-4075 mg GAE/100 g DW vs. 6500-10,600 mg/100 g DW [46]).…”

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“…Another pivotal feature of these natural metabolites is their structural diversities which also allow them to render versatile biological functions like antioxidant, antimicrobial, cytotoxic, anti-inflammatory properties etc. as well 1,2,3 .…”

Biological activity of infusion and decoction extracts of Hibiscus sabdariffa L. calyces

“…Total phenolic content of extracts was determined using the 96-well plate by method previously described (Olaokun et al, 2017). To extracts (20 μl) in a 96-well plate was added 100 μl of 20% Folin-Ciocalteu reagent and 80 μl of 7.5% sodium bicarbonate solution.…”

“…Total flavonoid content of extracts was determined using the 96-well plate method (Olaokun et al 2017). To extracts (100 μl) in a 96-well plate was added 100 μl of 2% aluminium chloride.…”