Antioxidant Capacity of Herzegovinian Wildflowers Evaluated by UV–VIS and Cyclic Voltammetry Analysis

Abstract

Considering the vast cultural and traditional heritage of the use of aromatic herbs and wildflowers for the treatment of light medical conditions in the Balkans, a comparison of the antioxidant capacity of wildflowers extracts from Herzegovina was studied using both cyclic voltammetry and spectrophotometry. The cyclic voltammograms taken in the potential range between 0 V and 800 mV and scan rate of 100 mV s−1 were used for the quantification of the electrochemical properties of polyphenols present in four aqueous plant extracts. Antioxidant capacity expressed as mmoL of gallic acid equivalents per gram of dried weight of the sample (mmoL GAE g−1 dw) was deduced from the area below the major anodic peaks (Q400 pH 6.0, Q500 pH 4.7, Q600 pH 3.6). The results of electrochemical measurements suggest that the major contributors of antioxidant properties of examined plants are polyphenolic compounds that contain ortho-dihydroxy-phenol or gallate groups. Using Ferric reducing-antioxidant power (FRAP) and 2,2′-azino-bis spectrophotometric methods (3-ethylbenzthiazoline-6-sulphonic acid) radical cation-scavenging activity (ABTS) additionally determined antioxidant capacity. The FRAP results ranged from 2.9702–9.9418 mmoL Fe/g dw, while the results for ABTS assays expressed as Trolox equivalents (TE) ranged from 14.1842–42.6217 mmoL TE/g dw. The Folin–Ciocalteu procedure was applied to determine the total phenolics content (TP). The TP content expressed as Gallic acid equivalents (GAE) ranged from 6.0343–9.472 mmoL GAE/g dw. The measurements of total flavonoid (TF) and total condensed tannin (TT) contents were also performed to obtain a broader polyphenolic profile of tested plant materials. Origanum vulgare L. scored the highest on each test, with the exception of TT content, followed by the Mentha × piperita L., Artemisia annua L., and Artemisia absinthium L., respectively. The highest TT content, expressed as mg of (−)catechin equivalents per gram of dried weight of sample (mg CE/g dw), was achieved with A. absinthium extract (119.230 mg CE/g dw) followed by O. vulgare (90.384 mg CE/g dw), A. annua (86.538 mg CE/g dw) and M. piperita (69.231 mg CE/g dw), respectively. In addition, a very good correlation between electrochemical and spectroscopic methods was achieved.

Green Inhibition of Corrosion of Aluminium Alloy 5083 by Artemisia annua L. Extract in Artificial Seawater

“…The vibration modes of other functional groups that could furthermore confirm the identity of phenolic acid adsorbed on the ALA surface could be overlapping with the vibration modes of the main corrosion products of both samples: γ-Al 2 O 3 and α-Al 2 O 3 . Our recent study showed that the oxidation of phenolic components responsible for the antioxidant activity of the aqueous extract of A. annua was reversible and that one of the main components of the examined plant extract was caffeic acid [ 42 ]. Earlier studies reported that the main organic components of A. annua aqueous extract were caffeic and feruloyl-quinic acid derivative [ 48 , 49 ], while this study confirmed that small molecules, such as chlorogenic and caffeic acid, readily diffused to the aqueous phase during 3 h maceration at room temperature.…”

“…The significant antioxidant activity of plant extracts is not restricted to a particular family and is mostly attributed to the synergetic effect of active constituents found in the extracts [ 20 ]. Our recent study suggests that Artemisia annua L. harvested in its naturally occurring habitat in Herzegovina exhibits high antioxidant activity and has a high content of phenolics, flavonoids, and tannins [ 42 ]. Artemisia annua L. is a wildflower known in traditional medicine for centuries [ 43 , 44 , 45 , 46 ].…”

Fermented Sprouts of Codonopsis lanceolata Suppress LPS-Induced Inflammatory Responses by Inhibiting NF-κB Signaling Pathway in RAW 264.7 Macrophages and CD1 Mice

“…These tubes were then incubated at 4 • C for 4 h and centrifuged at 3000 rpm for 10 min at 4 • C. After centrifugation, the supernatant was collected, and the non-tannin phenolics were measured using the same method to determine the total phenolics. The tannin content was determined by subtracting the non-tannin phenolics from the total phenolics [29]. The results were reported in milligrams of gallic acid equivalents per gram of dry weight of the extract, along with the SD for three replicate analyses.…”