ANTIOXIDANT POTENCY, pH AND HEAT STABILITY OF SELECTED PLANT EXTRACTS

Abstract

The potential of methanolic extracts of six green leafy vegetables, viz. Punica granatum, Ipomoea batatas L., Beta vulgaris, Daucus carota, Amaranthus paniculatus and Peucedanum graveolens, as a natural antioxidant was assessed. Two experimental models, namely 1,1‐diphenyl‐2‐picrylhydrazyl radical‐scavenging activity and iron (III) reducing capacity, were used to evaluate the antioxidant activity (AOA) of green leafy vegetables. The stability of extracts to pH (4, 7 and 9) and temperature (100C) was investigated. All the extracts showed varying degrees of antioxidant efficacy in a dose‐dependent manner. P. granatum had high glutathione and polyphenols, and D. carota had higher ascorbic acid and β‐carotene. The AOA of D. carota leaves, A. paniculatus and P. graveolens almost remained the same at pH 7 and 9. The extracts of D. carota leaves, A. paniculatus and P. graveolens showed increasing AOA after heat treatment. P. granatum was more heat stable than other extracts. PRACTICAL APPLICATIONS Recently, natural plants have received more attention as sources of biologically active substances, including antioxidants, antimutagens and anticarcinogens. Scientific information on the antioxidant properties of various plants that are less widely used in culinary and medicine is scarce. Therefore, six green leafy vegetables (Punica granatum, Ipomoea batatas L., Beta vulgaris, Daucus carota, Amaranthus paniculatus and Peucedanum graveolens) were selected for their antioxidant properties, antioxidant compounds and stability to pH and temperature. P. granatum L. (polyphenol‐rich) can be used in food industries, especially in food systems with varied pH. The extracts proved to be better radical scavengers rather than electron donors (reducing power), which depicts the mechanism through which they act as antioxidants. P. graveolens, A. paniculatus, D. carota and P. granatum, due to their heat stability, can be considered as antioxidants in formulations requiring heat treatment.

Use ofMoringa oleiferaFlower Pod Extract as Natural Preservative and Development of SCAR Marker for Its DNA Based Identification

“…Phenolic compounds are considered as effective hydrogen donor that makes them good antioxidant [ 54 ]. The results of the present study corroborate the results of previous studies where it has been reported that plant phenolic compounds govern antioxidant activity of plant extracts [ 28 , 55 – 57 ]. Therefore, aqueous extract of Moringa oleifera flower pods can be considered as a potent source of natural antioxidants.…”

Phenolic compounds and antioxidant activity of tuberous root leaves

“…A high content of total phenolics in methanol (86.16 ± 4.51 mg catechin/g) and acetone (78.8 ± 5.3 mg catechin/g) extracts was also reported for radish leaves by [16]. Results lower than those found in this study were reported by [14] , for the methanol extract of carrot (9.3 mg GAE/g), beet (6.1 mg GAE/g), and sweet potato (17.3 mg GAE/g) leaves. The difference between the reported values was possibly due to the use of only one type of solvent, which may have compromised the extraction efficiency of phenolic compounds.…”

“…Several studies reported the potential of tuberous root leaves as nutraceutical food. The leaves of carrot (Daucus carota L.) are natural sources of omega 3 and 6 [10] and are used in salads, soups, and in the preparation of food products; [10][11][12] beet (Beta vulgaris L.) leaves are used in food formulations to increase their nutritional value [13] ; the leaves of sweet potato (Ipomea batatas L.) have a high content of soluble fiber, polyphenols, and minerals, especially iron and vitamin E; [14] yam (Colocasia esculenta L.) leaves are consumed in sauces, purées, stews, and soups and are used in the treatment of scarring; [15] and radish (Raphanus sativus L.) leaves present a broad spectrum of antibacterial activity against foodborne pathogens. [16] Although several studies elucidated the antioxidant potential of most of these leaves, few analyze the content of phenolic compounds.…”

Aerial Parts of Peucedanum chenur Have Anti-Cancer Properties through the Induction of Apoptosis and Inhibition of Invasion in Human Colorectal Cancer Cells

“…Antioxidant effect of several genus of Peucedanum has been confirmed [14] . The methanolic extract of Peucedanum graveolens has a high thermal and pH stability, and its antioxidant effect increases at high temperatures and pH levels [44] . In this study, two antioxidant tests, DPPH and iron chelating, were used [14] .…”