To obtain protein hydrolysates from fresh water green algae Scenedesmus obliquus by three different enzymes and evaluate its antioxidant and antiviral activity. Enzymatic hydrolysates of green algae Scenedesmus obliquus protein were prepared by treatment with: 1.2% solution of pepsin, trypsin or papain. Protein was extracted from S. obliquus by three different extraction methods. Protein extracts and hydrolysates were assessed from stained gels following SDS-PAGE of samples. Antioxidant activity of protein hydrolysates was investigated. S. obliquus cells and protein extracts were rich in Arg, Lys, Asp, Ala, and His. Protein hydrolyzed by papain (Sd1pa) and protein hydrolyzed by trypsin (Sd2Try) induced highest antioxidant activity based on 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical-scavenging (41.41% and 40.62%) respectively, and on 2,2'-azinobis 3-ethyl-benzothiazoline-6-sulphonate (ABTS) radical (87.03% and 45.12%) respectively, at 150 µg/ml. The inhibitory effect and mode of action of protein hydrolysates were evaluated against Coxsackie B3 virus (CVB3). Protein hydrolyzed by papain (Sd2pa) and protein hydrolyzed by pepsin (Sd1pep) at 100 µg/ml exhibited antiviral activity (66.2% and 57.6%, respectively), against (CVB3) from all protein hydrolysates. S. obliquus protein hydrolysates have a potential as antioxidative neutraceutical ingredients and a potential therapeutic agent against CVB3.

Drought is regarded as one of the environmental constraints threatening agriculture worldwide. Melatonin is a pleiotropic molecule prevalent in plants capable of promoting plant endogenous resilience to many environmental challenges including drought. Banana is an important staple food consumed in developing countries especially in Africa. In this research, we studied the role of melatonin in the growth of bananas subjected to drought under the Egyptian semi-arid conditions. To achieve this objective, a field experiment on banana (Musa spp., cv. Williams) mother plants and first ratoon was conducted on a private farm for two seasons - 2019 and 2020. Three irrigation treatments, 100, 90 and 80% irrigation water requirements (IWR) were used in conjunction with four concentrations of melatonin as a foliar spray (0 μmol, 40 μmol, 60 μmol, and 80 μmol) to determine the effect of both treatments on banana plant performance under drought. The results showed that there was a substantial difference between treatments, with the foliar application of melatonin at 80 μmol concentration improving most of the yield attributes, relative water content, total chlorophyll and proline with water deficit. However, the foliar application of the molecule lowered the biochemical characteristics mostly at 80% IWR under the Egyptian semi-arid conditions. Overall, there was a concentration-dependent response with regards to IWR for the two seasons 2019 and 2020.

We investigated the effects of fucoxanthin isolated from the edible macroalga Dilophys fasciola on pathogenic microbes and probiotics in vitro and the antioxidant activity of fucoxanthin. The yield concentration of the obtained crude was 50.5% fucoxanthin. We found strong inhibition against Gram-positive Staphylococcus aureus and Listeria monocytogenes, and lower inhibition against Gram-negative bacteria and fungi. The probiotic strains progressed between 1.2 and 1.67 log cycles at a concentration of 30 μg/mL. The antioxidant activity ranged between 54.76% and 88.36% at a concentration of 40 μg/mL. The 50% lethal dose of algal fucoxanthin was shown to be more than 2511.88 mg/kg. The production of stirred yoghurt incorporated with 20 mg and 30 mg of fucoxanthin per kilogram of milk was evaluated through chemical, microbiological, and sensory analyses during storage for 21 days and compared with control samples. The maximum growth for probiotics (Bifidobacterium bifidum and Lacticaseibacillus casei) was found on day 14, but more viability counts were detected in the treatment with 30 mg/kg. All treatments were free from mould and yeast counts up to 7 days, and the small numbers of mould, yeast, and psychrotrophic counts appeared first in control samples. Also, the highest dry matter content was observed for treatments with 30 mg/kg. Moreover, the protein, fat, and ash content of all treatments increased with a progressive cold storage period. Greater reductions in the pH were found in treatments than in the control, and were consistent with the development of acidity. During storage, the amount of crude fucoxanthin had no significant impact on the flavour, colour, or appearance scores. Significance: Fucoxanthin is a type of carotenoid that offers many benefits to human health. The fucoxanthin of edible Dilophys fasciola had a strong antimicrobial effect against Gram-positive bacteria, Gram-negative bacteria, and fungi. Stirred yoghurt fortified with crude fucoxanthin had good overall acceptability and the percentage of crude fucoxanthin had no noticeable effects on the flavour, colour, or appearance. Fucoxanthin, therefore, has potential benefit as a food additive.

Imidacloprid (IMI), the main component of neonicotinoid insecticides, promotes oxidative stress and genotoxicity in mammals. The aim of this experiment is to assess oxidative stress in liver cells and genotoxicity of erythrocytes for rats exposed to sub-lethal doses of IMI and the protective effects for Rhodophyta as antioxidant material versus imidacloprid. A total of 30 adult male albino rats (average body weight, 190-200 g) were divided into six groups (n=5) as follows: group 1 served as the control, group 2 received 200 mg/kg red algae, group 3 received 45 mg/kg IMI (high-dose group), group 4 received 22.5 mg/kg IMI (low-dose group), group 5 received 200 mg/kg red algae +45 mg/kg IMI, and group 6 received 200 mg/kg red algae +22.5 mg/kg IMI. After 28 d of treatment, the antioxidant activity of the crude extract of red algae was assessed in terms of free radical scavenging activity and found to be higher in TCA (75.57%) followed by DPPH (50.08%) at concentration 100 μg extract and a significant increase in lipid peroxidation and reductions in glutathione were observed in liver cells were intoxicated with high and low doses of IMI. Moreover decreases in catalase and glutathione peroxidase parameters in same previous groups which indicated oxidative stress. In addition significant increases in micronucleus frequency (MN) in the bone marrow of the rats as a genotoxicity marker which indicated DNA damage in erythrocytes cells with alterations in the histopathology of liver cells were also noted such as necrosis, inflammatory cells, infiltration, and necrobiotic changes. Whereas Rhodophyta succeeded in alleviation the oxidative damage and genotoxicity induced by the insecticide. In conclusion, IMI demonstrates hazardous effects, such as alterations in antioxidant status and mutagenicity of erythrocytes and polysaccharides from Rhodophyta has good antioxidant activity in vivo model systems against imidacloprid.

Due to the damaging effects of root-knot nematodes on crops and the dangerous effects of chemical nematicides on both people and the environment in Egypt, the purpose of this study was to assess the power of polysaccharides and polyphenol extracts as well as their nano-forms from marine algae (Laurencia papillosaandDilophys fasciola) used as eco-friendly alternatives for the control ofMeloidogyne incognita. The nano-forms of algal extracts efficiently suppressedM. incognitaegg hatching and increased juvenile mortality compared to the control. The tested treatments effectively decreased galls and egg masses of tomato roots compared to the control in the field.Dilophys fasciolaextract and its nano-form showed promising nematicidal activity compared toL. papillosaextract. Generally, algal treatments boosted tomato plant defense system againstM. incognitaby triggering the production of some biochemical constituents such as phenolic compounds, polyphenol oxidase and chitinase enzymes. Consequently, the productivity and quality parameters of tomato fruits significantly increased.

Opuntia ficus peels or Prickly pear peel (PPP) is the waste byproduct obtained during fruit processing, the present study aims to extract polysaccharides from PPP and analyze it by HPLC. The biological potential activities as antioxidant, anti-inflammatory, antiviral, and anti Alzheimer of these polysaccharides were examined. Polysaccharides were extracted from PPP using hot water. Its composition was analyzed by HPLC. Profiles of 14 different natural mono sugars were identified. Stachyose, galactose, xylose, and sucrose were the most abundant sugars. Results indicated that the polysaccharides of PPP extract have antioxidant activity against DPPH and ABTS free radical. The scavenging activity of (150 µg /ml) of polysaccharides appeared to be interesting compared to synthetic antioxidants. Polysaccharides of PPP had 77.77% anti-inflammatory activity which is caused by inhibiting the heat-induced albumin denaturation and anti-Alzheimer effect (42.02%) compared to Donepezil drug (59.50%) in a dose-dependent manner. On the other hand polysaccharides of PPP extract showed no activity when tested against HSV-1 and Influenza A by plaque reduction assay. Thus, it could be suggested that polysaccharides PPP demonstrated potential biological activities as an antioxidant, anti-inflammatory, and anti-Alzheimer activities.