Evaluation of antioxidant and nitric oxide inhibitory activities of selected Malaysian medicinal plants

Abstract

Methanol extracts of seven Malaysian medicinal plants were screened for antioxidant and nitric oxide inhibitory activities. Antioxidant activity was measured by using FTC, TBA and DPPH free radical scavenging methods and Griess assay was used for the measurement of nitric oxide inhibition in lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma)-treated RAW 264.7 cells. All the extracts showed strong antioxidant activity comparable to or higher than that of alpha-tocopherol, BHT and quercetin in FTC and TBA methods. The extracts from Leea indica and Spermacoce articularis showed strong DPPH free radical scavenging activity comparable with quercetin, BHT and Vit C. Spermacoce exilis showed only moderate activity but other species were weak as compared to the standards. In the Griess assay Lasianthus oblongus, Chasalia chartacea, Hedyotis verticillata, Spermacoce articularis and Leea indica showed strong inhibitory activity on nitric oxide production in LPS and IFN-gamma-induced RAW 264.7 cells. Extracts from Psychotria rostrata and Spermacoce exilis also inhibited NO production but this was due to their cytotoxic effects upon cells during culture.

Phytochemical Evaluation and Antioxidant Activity of Essential Oil, and Aqueous and Organic Extracts of Artemisia dracunculus

“…The sample was then extracted by a percolator. The mixture was then concentrated at 50°C for dryness under reduced pressure (24,25).…”

Antioxidant Activity and Phytochemical Screening of Crude Endophytes Extracts of <i>Tabebuia argentea</i> Bur. & K. Sch.

“…The tubes were centrifuged at 3000 rpm for 30 min. Absorbance of the supernatant was evaluated at 532 nm in a spectrophotometer [26]. The antioxidant activity was calculated by percentage of inhibition in this method as follows:…”

Antioxidant Research in Asia in the Period from 2000-2008

“…Chinese Wolf-berry Solanaceae Leaf Antioxidant [99,100] Solanum melongena L. Egg plant Solanaceae Fruit Antioxidant [100] Chasalia chartacea No common name Rubiaceae Whole plant Antioxidant and NO inhibitory [135] Hedyotis verticillata L. Hedyotis plant Rubiaceae Whole plant Antioxidant and NO inhibitory [135] Lasianthus oblongus No common name Rubiaceae Whole plant Antioxidant and NO [135] King [135,151,152] Spermacoce articularis L. f. poaia Rubiaceae Whole plant Antioxidant and NO inhibitory [135] Spermacoce exilis (L. O. Pacific false buttonweed Rubiaceae Whole plant Antioxidant [135] Williams) C. D. Adams Citrus hystrix D.C Kaffir lime Rutaceae Leaf Antioxidant [99,100] Thea chinensis Sims. Green tea Theaceae Leaf Antioxidant [99,100] Piper sarmentosum Roxb.…”