HPTLC and ATR/FTIR Characterization of Antioxidants in Different Rosemary Extracts

Abstract

The effect of spontaneous fermentation by lactic acid bacteria on the extraction yield of bioactive compounds and antioxidant activity from rosemary leaf extracts was investigated using high-performance thin-layer chromatography (HPTLC). Brining and spontaneous fermentation with lactic acid bacteria more than doubled extraction of polyphenolics and antioxidants from the rosemary leaves. The results show that lactic acid fermentation enhances antioxidant activity in extracts by increasing the total phenolic content but does not increase extraction of phytosterols. Increased extraction of phenolic oxidants during fermentation assisted extraction, results from the in situ generated natural eutectic solvent from the plant sample. ATR-FTIR spectra from the bioactive bands suggests that this increased antioxidant activity is associated with increased extraction of rosmarinic acid, depolymerised lignin, abietane diterpenoids and 15-hydroxy-7-oxodehydroabietic acid.

Characterisation of the Phenolic Profile of Acacia retinodes and Acacia mearnsii Flowers’ Extracts

“…The spectra obtained with the ethanolic flowers’ extract ( Figure 2 ) display the strong influence of the compounds in this matrix. These results are similar to those obtained for rosemary [ 43 ], Cucurbitaceae [ 44 ], and medicinal plant extracts [ 45 ].…”

“…The peak at 1274 cm −1 could be related to asymmetric stretching vibrations of the C-O-C linkages in phenolic ethers (C-O stretch) and esters of phenolic hydroxyls [ 43 ].…”

The Effect of Aromatic Plant Extracts Encapsulated in Alginate on the Bioactivity, Textural Characteristics and Shelf Life of Yogurt

“…The FTIR spectra of rosemary, RE, and summer savory, SE ( Figure 2 ) are very similar. The characteristic vibration bands that can be found in the spectra of the two extracts are the following: a strong broad absorption band around 3400 cm −1 (phenolic -OH and -NH), 2924 and 2855 cm −1 (alkane -C-H), 1716 cm −1 (carbonyl -C=O), 1605 cm −1 (-NH, H-O-H, and alkene -C=C-) [ 54 , 55 ], 1510 cm −1 (aromatic -C=C-), 1407 cm −1 (alkane -C-H), 1360sh cm −1 (RE) (alkane -C-H) [ 56 ], 1266 cm −1 (ether C-O-C), 1167 and 1116 cm −1 (alcohol -C-O), 815 cm −1 (carboxylic O-C=O), and 630 cm −1 (C-Cl). Few differences can be observed between the two spectra, namely: the bands in 1716, 1510, 1167, and 1116 cm −1 , respectively, show lower intensity in the spectrum of the savory extract.…”

Physicochemical and Antioxidant Properties of Nanoliposomes Loaded with Rosemary Oleoresin and Their Oxidative Stability Application in Dried Oysters

“…The chemical structure and functional groups of RO, empty nanoliposomes, and RO nanoliposomes were analyzed to determine by FTIR spectra in Figure 1 . The spectra of RO revealed several typical peaks around 721 cm −1 (deformation vibration of C-H bond in benzene ring), 1160 cm −1 (deformation vibrations of O-H in-plane bending for phenol), 1502 cm −1 (stretching vibrations of benzene, pyridine, and other heteroaromatic rings), 1761 cm −1 (carbonyl C=O stretching at the ester bond), and 2859 cm −1 (alkyl C-H stretching vibration) [ 52 , 53 ]. These represent characteristic absorption peaks of functional groups in RO, which contain many polyphenolic compounds, including carnosic and rosmarinic acid [ 54 ].…”