Antioxidant Activity Of Rosmarinic Acid Research Articles

Antioxidant Activity of Rosmarinic Acid Extracted and Purified from Mentha piperita.

Rosmarinic acid was obtained from methanolic extract of Mentha piperita L. under a reflux condenser. The current study aimed to evaluate the in vitro antioxidant activities and rosmarinic acid levels of the methanol extracts of M. piperita. The analysis of the sample by high-performance liquid chromatography technique (HPLC) indicated that rosmarinic acid was present in high concentration 1.9 mg/mL in the extract. Purification was carried out by column chromatography to give 0.020 g from 1 g of crude extract, and then the antioxidant activity of purified rosmarinic acid was determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH), H2O2 scavenging, and REDOX methods. It was revealed that the anti-oxidant potential of the rosmarinic acid extract was greater than 95% (at 100 µg/mL) for DPPH assay and 87.83% (at 100 µg/ml) for H2O2 scavenging assay. This study was performed by using a reflux methanolic extraction of M. piperita. This possible instructional technique proved to be a quick and successful method for retaining the antioxidant properties of rosmarinic acid. The rosmarinic acid content was determined using HPLC.

Preparation and In Vivo Evaluation of Rosmarinic Acid-Loaded Transethosomes After Percutaneous Application on a Psoriasis Animal Model

The topical use of rosmarinic acid (RA) in skin inflammatory pathologies is restricted due to its poor water solubility, poor permeability, and chemical instability. In this study, RA-loaded transethosomes-in-Carbopol® formulations have been developed to evaluate its anti-inflammatory activity on imiquimod-induced psoriasis-like skin inflammation in mice. In vitro release profiles demonstrated sustained behavior due to the retentive action of gel and the entrapment of RA into the vesicles. However, the low viscosity of the combined formulation increased the drug release rate. Animal evaluation of anti-inflammatory activity demonstrated that transethosomes-in-gel containing dexamethasone (Dex-TE-Gel), as positive control, showed effect in all the pro-inflammatory parameters evaluated, evidencing that these drug-loaded nanocarriers have been effectively reached the site of action. In addition, transethosomes-in-gel containing RA (RA-TE-Gel) formulations produced a great reduction in the punch edema (P < 0.001) and in TNF-α and IL-6 (P < 0.05). However, non-significant differences were obtained for IL-1β, IL17, and MPO. Despite the protecting effect of Carbopol® and transethosomes on oxidation index and antioxidant activity of RA over the 7 days of treatment, however, a degradation process of this antioxidant to caffeic acid may be the cause of these in vivo results. We have also checked that the pH existing into the intercellular space of damaged cells (pH 6.8) may be affecting. Therefore, our results suggest that RA-TE-Gel could act as an effective RA formulation for skin delivery; further studies will help to understand the loss of activity at the cellular level.

Nanoantioxidant-Based Silica Particles as Flavonoid Carrier for Drug Delivery Applications.

Nanosystems used in pharmaceutical formulations have shown promising results in enhancing the administration of drugs of difficult formulations. In particular, porous silica nanoparticles have demonstrated excellent properties for application in biological systems; however, there are still several challenges related to the development of more effective and biocompatible materials. An interesting approach to enhance these nanomaterials has been the development of nanoantioxidant carriers. In this work, a hybrid nanoantioxidant carrier based on porous silica nanoplatform with rosmarinic acid antioxidant immobilized on its surface were developed and characterized. Techniques such as dynamic light scattering (DLS), zeta potential, transmission electron microscopy (TEM), N2 adsorption–desorption measurements, differential scanning calorimetry (DSC), Fourier transform–infrared spectroscopy (FT-IR), and 2,2-diphenyl-1-picrylhydrazyl (DPPH●) assay were used to characterize and evaluate the antioxidant activity of nanocarriers. In addition, drug release profile was evaluated using two biorelevant media. The antioxidant activity of rosmarinic acid was maintained, suggesting the correct disposition of the moiety. Kinetic studies reveal that more morin is released in the simulated intestinal fluid than in the gastric one, while an anomalous non–Fickian release mechanism was observed. These results suggest a promising antioxidant nanocarrier suitable for future application in drug delivery.

Complexation of rosmarinic acid with hydroxypropyl-β-cyclodextrin and methyl-β-cyclodextrin: Formation of 2:1 complexes with improved antioxidant activity

Rosmarinic acid (RA) is a phenolic compound with remarkable antioxidant activity; however it presents low bioavailability. Cyclodextrin (CD) derivatives, such as hydroxypropyl-β-CD (HPβCD) and methyl-β-CD (MβCD), have been used to solve the low bioavailability of drugs, increasing their solubility or permeability. The aim of the present study was to investigate the complexation of RA with two derivative CDs, HPβCD and MβCD, and the resulting antioxidant activity. A phase-solubility study was performed to determine the stoichiometric ratio and apparent stability constant, and electrospray ionization coupled to mass spectroscopy (ESI–MS) was used to confirm the stoichiometric ratio. The freeze-dried (FD) complexes were characterized by liquid chromatography (LC), differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and nuclear magnetic resonance (NMR). The antioxidant activity of RA and the FD complexes was evaluated by the DPPH method. A 2:1 (RA:CD) stoichiometric ratio and strong apparent constant stability were found for both complexes using a phase-solubility study, and ESI-MS spectra confirmed a signal corresponding to the 2:1 complex. The FD complexes showed high yield and RA content. The results of DSC, FTIR and SEM demonstrate changes in the physical-chemical characteristics of RA, suggesting its interaction with CDs. These interactions were confirmed by NMR, which revealed the formation of inclusion and non-inclusion complexes. The antioxidant activity of the RA:HPβCD and RA:MβCD FD complexes were higher than that of RA. The results suggest that FD complexes can be a technological approach to the development of formulations containing high content of RA with a view to increasing antioxidant potential.

Antioxidant activity of rosmarinic acid and its principal metabolites in chemical and cellular systems: Importance of physico-chemical characteristics

Persistent accumulation of reactive oxygen species causes cellular oxidative stress which contributes strongly towards the induction and progression of various diseases. Therapeutic focus has therefore shifted towards the use of antioxidants, with recent interest in those of plant origin. In the current study, rosmarinic acid (RA) and its key metabolites were evaluated in non-cellular and cellular antioxidant assays, using quercetin (Q) as a positive control. The non-cellular assay was performed as scavenging of DPPH radical, whilst the cellular assay was performed as protection from an oxidant stress. Radical-scavenging activity of RA and two of its primary metabolites, CA and DHPLA, were comparable to that of Q, whilst FA was of lower potency and m-CoA was inactive. In the cellular assay, RA and CA were markedly less potent than Q, with DHPLA, FA and m-CoA being inactive, this being true in short-term (5-h) or long-term (20‐h) exposure conditions. However, antioxidant potency of Q and methyl rosmarinate, a non-ionisable ester of RA, was similar in the non-cellular and short-term cellular assays. It is proposed that marked ionisation of organic acids such as RA and its metabolites at physiological pH greatly limits their intracellular accumulation, and so attenuates intrinsic antioxidant ability demonstrated in the non-cellular assay. This study demonstrates some of the factors that prevent well-known phytochemicals from progressing further along the drug discovery chain.

Study of antioxidant and membrane activity of rosmarinic acid using different model systems

Rosmarinic acid is found in many species of different families of higher plants and its chemical structure is phenol propanoid with various biological activity. In this paper, we conducted a comparative study of antioxidant (radical-scavenging) properties of rosmarinic acid in systems of 2,2'-azo-bis(2-methylpropionamidin)dihydrochloride-luminol and hemoglobin-hydrogen peroxide-lu- minol, determined its protective potential in preventing peroxidation of linoleic acid, and evaluated the effect on the permeability of planar bilayer lipid membranes. Linoleic acid peroxidation was assessed by iron-thiocyanate method. In these studies, trolox was used as a reference antioxidant, and ascorbic acid, and dihydroquercetin were taken as standards. Rosmarinic acid is significantly superior to trolox, ascorbic acid and dihydroquercetin in the tests for antioxidant activity in the systems studied, as well as in inhibition of linoleic acid peroxidation. According to their activity the investigated substances can be arranged in the following order: rosmarinic acid > dihydroquercetin trolox > ascorbic acid. Rosmarinic acid does not cause significant changes in the permeability of planar bilayer membranes in a dose range of 0.5 to 10 mkg/mL. Antioxidant activity of rosmarinic acid is due to the neutralization of reactive oxygen species and/or luminol radicals generated in model systems. The observed features of the antioxidant and membrane activity of rosmarinic acid, which may underlie the previously mentioned pharmacological effects are discussed.

Microencapsulation of rosmarinic acid using polycaprolactone and various surfactants

Rosmarinic acid (RA) has a number of interesting biological activities, e.g. anti-viral, anti-bacterial, anti-inflammatory and antioxidant. The antioxidant activity of RA is stronger than that of vitamin E. Despite its strong antioxidant activity, it was limited to use in cosmetics because of the low water solubility, discolouration and chemical instability. The purpose of this study was to prepare RA-loaded polycaprolactone (PCL) microspheres using emulsion solvent evaporation method and characterize them with different surfactants used in the formation process. Finally, long-term stability of RA was evaluated in the cosmetic formulation. As a result, PCL microspheres were found to be spherical in shape, with zwitterionic surfactant-PCL particles being the smallest size distribution and highest entrapment efficiency of RA. Emulsions containing RA-loaded PCL microspheres showed a better long-term stability of the RA compared with those containing only RA. These results suggest that RA may be stably and efficiently encapsulated into polycaprolactone microspheres.

Synthesis, stabilisation and surface modification of gold and silver nanoparticles by rosmarinic acid and its analogues

The aim of this study was to show that an antioxidant may be able to synthesise and stabilise metal nanoparticles while the same molecule might be adsorbed on the surfaces of the particles for their targeted delivery. Biochemical assay and pulse radiolysis technique with kinetic spectrophotometric detection have been employed to show the antioxidant activity of rosmarinic acid. It has been observed that the molecule can protect thiol from free radical induced damage. The reaction of a model peroxyl radical with rosmarinic acid is very fast in the first step possibly through electron transfer. An intramolecular rearrangement takes place in the second step with the formation of phenoxyl radical. Rosmarinic acid and its analogues caffeic acid and dihydrocaffeic acids were not only able to reduce gold and silver ions but they could stabilise nanoparticles of these noble metals. The particles were characterised by transmission electron microscopy. The UV Visible absorption spectra of the silver sol before and after the addition of rosmarinic acid show the transverse plasmon peak, and the longitudinal plasmon peak for silver nano-rods. TEM image of the nanoparticles after surface modification shows the formation of nano-rods. These were formed by assembly of spherical nanoparticles. Along with the nano-rod formation other nanostructures could also be detected. Rosmarinic acid here is acting as a stabiliser and a surface-passivating agent.

Protective effect of rosmarinic acid on V79 cells evaluated by the micronucleus and comet assays

Rosmarinic acid (RA) is a naturally occurring phenolic compound, which contributes to the beneficial and health-promoting effects of herbs, spices and medicinal plants. RA has shown several biological activities, such as hepatoprotective, anti-inflammatory, antiangiogenic, antitumor, antidepressant, antineurodegenerative, HIV-1 inhibitory and antioxidant effects. The aim of this study was to investigate the ability of RA to prevent chemically induced chromosome breakage or loss and primary DNA damage using the micronucleus and comet assays with V79 cells, respectively. The chemotherapeutic agent doxorubicin (DXR; 0.5 microg ml(-1)) was used as the DNA-damaging agent. The cultures were treated with different concentrations of RA (0.28, 0.56 and 1.12 mm) alone or in combination with DXR. The results showed that RA exerted no genotoxic effect, but significantly reduced the frequency of micronuclei and the extent of DNA damage induced by DXR at the three concentrations tested. The antioxidant activity of RA might be involved in the reduction of DXR-induced DNA damage observed in the present study.

The interference of rosmarinic acid in the DNA fragmentation induced by osmotic shock

The induction of cell death in human erythroleukemic cells (K562) by sorbitol shows the typical apoptotic changes in ultrastructural morphology, including blebbing, chromatin condensation and nuclear membrane breakdown. Using a cytofluorimetric approach, we found that sorbitol induced production of reactive oxygen species (ROS) followed by DNA fragmentation in leukemic cells. In this study, we investigated effect of curcumin and rosmarinic acid on cell viability in three different cell lines: erythroleukemia K562, papillary NPA, and anaplastic ARO thyroid cancers. Curcumin was able to induce apoptosis in a concentration- and time dependent manner in three cell lines, while rosmarinic acid was less effective on this process. To examine this possibility in cellular system, this study evaluated the capacities of both compounds acting as antioxidant inhibiting sorbitol-induced apoptosis. K562, NPA and ARO cells were pre-incubated with 25 microM rosmarinic acid to allow the uptake and then the cell lines were treated with 1 M sorbitol. Afterwards, the cells were subjected to agarose gel electrophoresis to assess the DNA fragmentation. In conclusion, the antioxidant activity of rosmarinic acid is able to inhibit sorbitol-induced apoptosis.

GENETIC VARIATION OF PHENOLIC COMPOUNDS CONTENT, ESSENTIAL OIL COMPOSITION AND ANTI OXIDATIVE ACTIVITY IN ISRAEL-GROWN MENTHA LONGIFOLIA L.

Phenolic acids, in free soluble form and cell wall-bound, were extracted from leaves and stems from 40 genetic variants from 25 populations of Mentha longifolia native to Israel. Rosmarinic and caffeic acid were the most abundant freely soluble acids whereas caffeic acid was most abundant among cell wall-bound phenolic acids. Assessment of the total antioxidant efficacy, based on the reduction of 1,1-diphenyl-2-picryldrazyl (DPPH), revealed high antioxidant activity by tissues of many M. longifolia variants, stemming in part, from antioxidant activity of rosmarinic acid. Although phenolic acids in free extractable form comprise a major portion of total phenolic acids, cell wall-bound acids were found in significant amounts and may also contribute to the antioxidant efficacy of the plants.

DFT study on the antioxidant activity of rosmarinic acid

A theoretical calculation based on the density functional theory (DFT) has been performed to understand the antioxidant activity of rosmarinic acid in view of a molecular structure. According to the geometry of the ground state molecule and its free radical, the HOMO and LUMO, the O–H bond dissociation energy (BDE), and the single electron density distribution of the radicals, we interpreted the capacity of scavenging the radicals for rosmarinic acid by its structure. Compared with flavonoids, the higher antioxidant activity of rosmarinic acid may be from the abstraction of hydrogen atoms of the ortho-position hydroxyls on the rings A and B. This abstraction can occur continuously to form a semiquinone structure, or even to form a quinone structure. The activity of the ring A is similar with the ring B. However, the ring B is a stronger electron donor than the ring A, and, the radical formed from the H-abstraction of the ring A is more stable than that of the ring B. We also found that there is a good relationship between the BDE, which is used to show the stability of the parent molecule and the unpaired electron delocalization correlated to the stability of the free radical. These theoretical researches will be helpful to the development for the antioxidant compounds.

Phenolics composition and antioxidant activity of sweet basil (Ocimum basilicum L.).

The antioxidant activity of a methanolic extract of Ocimum basilicum L. (sweet basil) was examined using different in vitro assay model systems. The crude extract was fractionated on a Sephadex LH-20 column, and six fractions were identified. The DPPH scavenging assay system and the oxidation of the soy phosphotidylcholin liposome model system were used to evaluate the antioxidant activity of each fraction. Fraction IV showed the strongest activity followed by fractions V and VI. Phenolic compounds responsible for the antioxidative activity of the fractions were characterized by atmospheric pressure chemical ionization liquid chromatography-mass spectrometry. The major antioxidant compound in fraction IV was confirmed as rosmarinic acid by (1)H NMR and characteristic fragmentations in the mass spectrum. Moreover, the native of antioxidant activity of rosmarinic acid in the liposome system was examined. The results showed that one rosmarinic acid can capture 1.52 radicals, and furthermore, the existence of a synergistic effect between alpha-tocopherol and rosmarinic acid was revealed.