Lippia origanoides essential oil increases longevity and ameliorates ß-amyloid peptide-induced toxicity in Caenorhabditis elegans.

Lippia origanoides essential oil (LOEO) is extensively utilised as food preservative due to its antioxidant and antibacterial activities. In this study, the antioxidant and anti-ageing effects of LOEO was investigated in vivo using the nematode Caenorhabditis elegans. The gas chromatography-mass spectrometry analysis indicated that the main components of LOEO are carvacrol and thymol. LOEO treatment improved physiological parameters such as pharyngeal pumping, locomotion and body size indicating that is not toxic to C. elegans. LOEO treatment showed antioxidant effect in C. elegans by reducing endogenous ROS (Reactive Oxygen Species) production and increasing their survival under oxidative stress. Finally, LOEO treatment significantly extended C. elegans lifespan and alleviated the paralysis induced by ß-amyloid peptide overexpression in the muscle. This work demonstrates for the first time LOEO antioxidant and anti-ageing properties on an organism level providing a valuable proof of principle to support further studies in the development of nutraceuticals or antioxidant phytotherapy.

Preparation, Structural Characterization, and Property Investigation of Gallic Acid-Grafted Fungal Chitosan Conjugate.

Oxidative stress is the cause of numerous diseases in humans; therefore, there has been a continuous search for novel antioxidant molecules. Fungal chitosan is an attractive molecule that has several applications (antifungal, antibacterial, anticancer and antiparasitic action) owing to its unique characteristics; however, it exhibits low antioxidant activity. The aim of this study was to obtain fungal chitosan (Chit-F) from the fungus Rhizopus arrhizus and synthesize its derivative, fungal chitosan-gallic acid (Chit-FGal), as a novel antioxidant chitosan derivative for biomedical use. A low molecular weight Chi-F (~3.0 kDa) with a degree of deacetylation of 86% was obtained from this fungus. Chit-FGal (3.0 kDa) was synthesized by an efficient free radical-mediated method using hydrogen peroxide (H2O2) and ascorbic acid. Both Chit-F and Chit-FGal showed similar copper chelating activities; however, Chit-FGal was more efficient as an antioxidant, exhibiting twice the total antioxidant capacity than Chi-F (p < 0.05). Furthermore, H2O2 (0.06 M) promoted a 50% decrease in the viabilities of the 3T3 fibroblast cells. However, this effect was abolished in the presence of Chit-FGal (0.05-0.25 mg/mL), indicating that Chit-FGal protected the cells from oxidative damage. These results suggest that Chit-FGal may be a promising agent to combat oxidative stress.

Oligochitosan Synthesized by Cunninghamella elegans, a Fungus from Caatinga (The Brazilian Savanna) Is a Better Antioxidant than Animal Chitosan.

Animal chitosan (Chit-A) is gaining more acceptance in daily activities. It is used in a range of products from food supplements for weight loss to even raw materials for producing nanoparticles and hydrogel drug carriers; however, it has low antioxidant activity. Fungal oligochitosan (OChit-F) was identified as a potential substitute for Chit-A. Cunninghamella elegans is a fungus found in the Brazilian savanna (Caatinga) that produces OligoChit-F, which is a relatively poorly studied compound. In this study, 4 kDa OChit-F with a 76% deacetylation degree was extracted from C. elegans. OChit-F showed antioxidant activity similar to that of Chit-A in only one in vitro test (copper chelation) but exhibited higher activity than that of Chit-A in three other tests (reducing power, hydroxyl radical scavenging, and iron chelation). These results indicate that OChit-F is a better antioxidant than Chit-A. In addition, Chit-A significantly increased the formation of calcium oxalate crystals in vitro, particularly those of the monohydrate (COM) type; however, OChit-F had no effect on this process in vitro. In summary, OChit-F had higher antioxidant activity than Chit-A and did not induce the formation of CaOx crystals. Thus, OChit-F can be used as a Chit-A substitute in applications affected by oxidative stress.

Gallic Acid-Laminarin Conjugate Is a Better Antioxidant than Sulfated or Carboxylated Laminarin.

A 12.4 kDa laminarin (LM) composed of ß(1→3)-glucan with ß(1→6)-branches was extracted from brown seaweed Lobophora variegata and modified via carboxylation using dielectric barrier discharge (LMC), conjugation with gallic acid (LMG), and sulfation (LMS). Analyses of the chemical composition of LMC, LMG, and LMS yielded 11.7% carboxyl groups, 1.5% gallic acid, and 1.4% sulfate content, respectively. Antioxidant activities of native and modified laminarins were assessed using six different in vitro methods. Sulfation stopped the antioxidant activities of LM. On the other hand, carboxylation improved cooper chelation (1.2 times). LMG was found to be a more efficient antioxidant agent than LM in terms of copper chelation (1.3 times), reducing power (1.3 times), and total antioxidant capacity (80 times). Gallic acid conjugation was further confirmed using Fourier transform infrared spectroscopy (FT-IR) and one- and two-dimensional NMR spectroscopy analyses. LMG also did not induce cell death or affect the cell cycle of Madin-Darby canine kidney (MDCK) cells. On the contrary, LMG protected MDCK cells from H2O2-induced oxidative damage. Taken together, these results show that LMG has the potent antioxidant capacity, and, therefore, potential applications in pharmacological and functional food products.