In this study, the release of proteins and other biomolecules into an aqueous media from two red macroalgae (Sphaerococcus coronopifolius and Gelidium spinosum) was studied using eight different cell disruption techniques. The contents of carbohydrates, pigments, and phenolic compounds coextracted with proteins were quantified. In addition, morphological changes at the cellular level in response to the different pretreatment methods were observed by an optical microscope. Finally, the antioxidant capacity of obtained protein extracts was evaluated using three in vitro tests. For both S. coronopifolius and G. spinosum, ultrasonication for 60 min proved to be the most effective technique for protein extraction, yielding values of 3.46 ± 0.06 mg/g DW and 9.73 ± 0.41 mg/g DW, respectively. Furthermore, the highest total contents of phenolic compounds, flavonoids, and carbohydrates were also recorded with the same method. However, the highest pigment contents were found with ultrasonication for 15 min. Interestingly, relatively high antioxidant activities like radical scavenging activity (31.57–65.16%), reducing power (0.51–1.70, OD at 700 nm), and ferrous iron-chelating activity (28.76–61.37%) were exerted by the different protein extracts whatever the pretreatment method applied. This antioxidant potency could be attributed to the presence of polyphenolic compounds, pigments, and/or other bioactive substances in these extracts. Among all the used techniques, ultrasonication pretreatment for 60 min appears to be the most efficient method in terms of destroying the macroalgae cell wall and extracting the molecules of interest, especially proteins. The protein fractions derived from the two red macroalgae under these conditions were precipitated with ammonium sulfate, lyophilized, and their molecular weight distribution was determined using SDS-PAGE. Our results showed that the major protein bands were observed between 25 kDa and 60 kDa for S. coronopifolius and ranged from 20 kDa to 150 kDa for G. spinosum. These findings indicated that ultrasonication for 60 min could be sufficient to disrupt the algae cells for obtaining protein-rich extracts with promising biological properties, especially antioxidant activity.

Pulmonary fibrosis (PF) remains one of the most serious pneumopathies whose diagnosis and physiopathogenesis are still poorly understood and no treatment has been shown to be effective. Recently, many studies have shown a renewed interest in plants thanks to their pharmacological potentials, like horehound, known, for its anti-inflammatory and antioxidant activities. The present study investigated the effects of the aqueous extract of horehound (Mae) on bleomycin (BLM)-induced PF in rats. Thirty rats were divided into three groups. The control group received no treatment, the BLM group received only intratracheally BLM (2 mg/kg), and the Mae group underwent administration of BLM+ Mae (2 mL/kg) daily for 20 days. Obtained results showed that Mae, rich in polyphenols, could significantly improve the damage caused by BLM by reducing the inflammatory index and the fibrosis score, bringing the lung structure of fibrotic rats close to that of control rats. As well, Mae obviously acted on the BLM inflammatory reaction, and the counting of bronchoalveolar lavage fluid (Balf) cells showed an increase in total cell number and a decrease in the infiltration of inflammatory cells in the bronchoalveolar space. In addition, the BLM instillation was accompanied by oxidative stress in the lung, liver, and kidney tissues, proven by an increase in lipid peroxidation, as well as through depletion of superoxide dismutase (SOD) and catalase (CAT). The Mae treatment reversed all disturbances of BLM-induced oxidative stress parameters promoting antioxidant and anti-inflammatory of the latter. These findings point to Mae as a promising candidate for the treatment of pulmonary fibrosis.

Idiopathic pulmonary fibrosis is a chronic and progressive respiratory disease whose diagnosis and physiopathogenesis are still poorly understood and for which, until recently, there were no effective treatments. Over the past few decades, many studies have demonstrated that marine macroalgae such as red seaweeds are potential alternative sources of useful bioactive compounds possessing various physiological and biological activities. The present study was aimed to investigate the effect of Corallina officinalis aqueous extract (COAE) against bleomycin (BLM)-induced lung fibrosis in rat. Thus, Wistar rats were divided into 4 groups of 10 each: control, BLM (2 mg/kg), BLM/COAE-150 mg/kg and BLM/COAE-300 mg/kg once a day for 21 days. Obtained results showed that COAE is rich in phenolic compounds and exhibited relatively high antioxidant activity. COAE might significantly reduce the damage caused by BLM by rewarding the decline in weight and pulmonary index in rats given only BLM. Moreover, lungs, liver and kidneys lipid peroxidation, and sulfhydryl group levels were reversed significantly in a dose‐dependent manner in the COAE‐treated groups. BLM decreased superoxide dismutase (SOD) and catalase (CAT) activities, while COAE administration increased the antioxidant enzyme activities. Histopathologically, COAE attenuates the severity of the inflammatory lungs state caused by instillation of BLM in rats. These findings suggest that COAE can be a potential therapeutic candidate against BLM-induced lung fibrosis.

In this study, we investigate the effect of different enzyme/substrate ( E / S ) ratios on the antioxidant and antibacterial properties of protein hydrolysates from two unexplored red macroalgae, namely, Sphaerococcus coronopifolius (SCPH) and Gelidium spinosum (GSPH). Antioxidant properties were evaluated using DPPH radical scavenging capacity, reducing power, ferrous ion chelating ability, and total equivalent antioxidant capacity. On the other hand, antibacterial activities were evaluated using agar diffusion and minimum inhibitory concentration (MIC) methods against six bacterial strains ( Listeria monocytogenes , Staphylococcus aureus , Kocuria rhizophila , Micrococcus luteus , Escherichia coli , and Salmonella newport ). The biopreservative effect of SCPH and GSPH on minced meat quality during 11 days of storage at 4°C was also studied focusing on lipid oxidation status and microbial growth. Both protein hydrolysates have considerable antioxidant activities whatever the E / S ratio used, in terms of scavenging DPPH radical (IC ₅₀ ranging from 0.12 to 3.22 mg/mL) and metal chelating activity (IC ₅₀ ranging from 0.15 to 2.24 mg/mL). At 5 mg/mL, the reducing power of SCPH and GSPH varied from 1.16 to 2.87. Moreover, SCPH and GSPH exhibited strong antibacterial activity against all tested bacteria, with MIC values ranging from 1.56 to 25 mg/mL. In addition, the incorporation of SCPH and GSPH into minced beef meat significantly ( p < 0.05) inhibited lipid peroxidation and microbial growth during 11 days of storage at 4°C. At the end of the storage period, the TBARS values measured in the groups treated with 1% ( w / w ) SCPH and GSPH were significantly reduced to 1.36 ± 0.003 and 1.34 ± 0.01 mg MDA/kg meat, respectively. Overall, the results showed that the addition of both protein hydrolysates has a positive effect on meat quality and suggest that SCPH and GSPH can serve as effective natural additives, enhancing the biopreservation and shelf life of refrigerated minced beef.

Actuellement, les macroalgues marines constituent une ressource biologique et économique de premier plan. En effet, les molécules naturelles issues de cette biomasse comportent une multitude de principes bioactifs à fort potentiel nutritionnel et pharmaceutique. Dans un premier temps, nous nous sommes concentrés sur la mise en place d'une méthode efficace pour la destruction de la paroi algale et la libération des protéines à partir de deux espèces de macroalgues rouges (S. coronopifolius et G. spinosum). Le prétraitement de ces biomasses par Ultrasonication pendant 60 min s'est avérée la technique la plus adéquate pour l'extraction des protéines. Ensuite, ces dernières ont été digérés par la pepsine (pH 3.5 and 40 °C) pendant 24 h pour l'élaboration de plusieurs hydrolysats protéiques enrichis en peptides bioactifs à partir de S. coronopifolius et G. spinosum, et nommés respectivement HPSC et HPGS. L'analyse peptidomique a permis d'identifier un nombre important de peptides à partir de HPSC et HPGS (172 et 64, respectivement). Aussi, 579 et 472 peptides uniques et non toxiques ont identifié par RP-HPLC-MS/MS à partir des différentes fractions de HPSC et HPGS. Plusieurs séquences peptidiques telles que FLPNF, LLGF, LFGF, MEPGPLGW, TPGF et FGGG ont été identifiées pour la première fois à partir des macroalgues rouges. L'analyse in silico QSAR a permis d'identifier une proportion élevée de peptides prédits comme inhibiteurs puissants de l'ECA (CI50 < 100 µM) et la DPP-IV (CI50< 2 mM). Dans un autre volet, nous nous sommes intéressés à l'étude des propriétés antioxydantes et antibactériennes in vitro de HPSC et HPGS et leur utilisation potentielle comme bio-conservateur de la viande bovine. En effet, HPSC et HPGS ont présenté un pouvoir antioxydant important et une forte activité antibactérienne ainsi qu'un impact positif sur la biopréservation de la qualité de la viande hachée et la prolongation de sa durée de conservation au cours de la réfrigération. Enfin, ces hydrolysats protéiques ont exercé aussi des propriétés antihypertensives et antidiabétiques in vitro et in vivo. En effet, l'administration orale d'une dose unique (100 et 200 mg/kg, pc) de HPSC et HPGS réduit significativement (p < 0,05) les pressions artérielles systoliques et diastoliques chez les rats hypertendus et améliore considérablement (p < 0,05) les indicateurs de stress oxydatif, la glycémie et les paramètres biochimiques chez les rats diabétiques. De ce fait, les protéines des macroalgues rouges représentent une source potentielle de peptides actifs et bénéfiques qui pourraient être utilisées en tant que « Supplément Nutritionnel » dans le développement d'aliments fonctionnels pour la prévention contre plusieurs pathologies. Ainsi, la production de fractions peptidiques actives ou de biopeptides issues de cette bioressource renouvelable est sans doute d'un très grand intérêt industriel.