Antioxidant Properties Of Methanolic Extracts Research Articles

Antioxidant properties of methanolic extracts from two kinds of Antrodia camphorata mycelia

Red and white mycelia of Antrodia camphorata (Zang and Su) were obtained due to different fermentation operations. The antioxidant properties and antioxidant components of methanolic extracts from these two mycelia were studied. Using the conjugated diene method, the antioxidant activity of methanolic extracts from white mycelia was better than that from red mycelia (EC 50 3.11 vs. 19.8 mg ml −1). Both mycelia were efficient in the reducing power and scavenging effect on 1,1-diphenyl-2-picrylhydrazyl radicals but white mycelia showed significantly lower EC 50 values (1.56 and 1.70 mg ml −1, respectively). At 7.5–10 mg ml −1, the chelating effects on ferrous ions reached a plateau of 95.7–98.7% for both mycelia. However, the EC 50 value was lower for red mycelia. Contents of antioxidant components were found to be in the order of tocopherols > total phenols > ascorbic acid > β-carotene. Methanolic extracts from A. camphorata red and white mycelia were good in the antioxidant properties tested, except for the scavenging effect on hydroxyl ions. Although contents of total antioxidant components were relatively high in red mycelia, the antioxidant properties were better with the methanolic extract from white mycelia.

Antioxidant properties of Indian medicinal plants.

The antioxidant properties of methanol extracts of 12 Indian medicinal plants, traditionally used in disease areas that probably involve free radical mechanisms, were evaluated by two methods, namely the DPPH (1,1-diphenyl-2-picryl hydrazyl) test and the lipid peroxidation assay. In the latter assay, seven of these extracts showed 90% or more activity compared with the standard, vitamin E and hence were studied in detail after the removal of interfering pigments. The selective pigment removal from the extracts led to an increase in free radical scavenging activity and a decrease in inhibition of lipid peroxidation.

Antioxidant properties of solvent extracts from Terminalia catappa leaves

Solvent extracts were prepared from green, yellow fallen and red fallen leaves of Terminalia catappa L. and their antioxidant activities were evaluated. Other antioxidant properties of methanolic extracts, including reducing power, scavenging and chelating effects, were also determined. The yields were consistently in the order of yellow fallen (6.34–10.50%)>red fallen (5.12–9.98%)>green leaf extracts (2.36–6.08%) for four solvents used. Higher yields were obtained from extraction with ethyl acetate or methanol than with dichloromethane or pentane. For three different leaves, the antioxidant activities were in the order methanol>ethyl acetate>dichloromethane>pentane extracts and all showed a parabolic-like curve with the maximum at 0.1–0.5 mg ml −1 of solvent extract. Reducing powers of three methanolic extracts and their scavenging effects on 1,1-diphenyl-2-picrylhydrazyl radicals were excellent at 0.5 and 0.1 mg ml −1, respectively. At 30 mg ml −1, chelating effects of methanolic extracts from green, yellow fallen and red fallen leaves on ferrous ions were 77.3, 48.6 and 48.3%, respectively.

Antioxidant properties of methanolic extracts from several ear mushrooms.

Five kinds of ear mushrooms are commercially available in Taiwan, including black, red, jin, snow, and silver ears. Methanolic extracts were prepared from these ear mushrooms, and their antioxidant properties were studied. For all methanolic extracts from ear mushrooms, the antioxidant activities in the 1,3-diethyl-2-thiobarbituric acid method were moderate (38.6 approximately 74.6%) at 1.0-5.0 mg/mL. Methanolic extracts from red, jin, and snow ears showed excellent antioxidant activities in the conjugated diene method at 5.0 mg/mL. At 5.0 mg/mL, reducing powers of methanolic extracts were in the descending order of snow > black approximately red approximately jin > silver ears. The scavenging effect of methanolic extracts from ear mushrooms on 1,1-diphenyl-2-picrylhydrazyl radicals was excellent except for that from silver ears. Ear mushroom extracts were not good scavengers for hydroxyl free radicals but were good chelators for ferrous ions. Naturally occurring antioxidants, including ascorbic acid, tocopherols, and total phenols, were found in the methanolic extracts. However, beta-carotene was not detected. Total antioxidant components were 15.69, 30.09, 27.83, 49.17, and 31.70 mg/g for black, red, jin, snow, and silver ears, respectively.

Evaluation of the antioxidant properties of a methanolic extract from ‘Juice Plus fruit’ and ‘Juice Plus vegetable’ (dietary supplements)

The antioxidant properties of methanolic extracts from ‘Juice Plus fruit’ and ‘Juice Plus vegetable’, which are sold in capsule form as dietary supplements, were evaluated using a range of established in vitro antioxidant assays. The values are compared to representative extracts from equivalent amounts (by dry weight) of selected fruits and vegetables prepared by the same method. Although there are some differences between the results of each assay, in general Juice Plus performed about equally to the fresh fruit and vegetables on a dry weight basis. This implies that, based on in vitro assays to measure antioxidant potential, one capsule of ‘Juice Plus fruit’ or ‘Juice Plus vegetable’ (weighing 1 g) is equivalent to about 10 g (fresh weight) of fruit or vegetable.