Biosynthesis Pathways of Vitamin E and Its Derivatives in Plants

Naturally occurring vitamin E, comprised of four forms each of tocopherols and tocotrienols, are synthesized solely by photosynthetic organisms and function primarily as antioxidants. The structural motifs of the vitamin E family and specifically the chroman moiety, are amenable to various modifications in order to improve their bioactivities towards numerous therapeutic targets. Tocopherols are lipophilic antioxidants and together with tocotrienols belong to the vitamin-E family. These lipid-soluble compounds are potent antioxidants that protect polyunsaturated fatty acids from lipid peroxidation. Biosynthetic pathways of plants producing a diverse array of natural products that are important for plant function, agriculture, and human nutrition. Edible plant-derived products, notably seed oils, are the main sources of vitamin E in the human diet. The biosynthesis of tocopherols takes place mainly in plastids of higher plants from precursors derived from two metabolic pathways: homogentisic acid, an intermediate of degradation of aromatic amino acids, and phytyldiphosphate, which arises from methylerythritol phosphate pathway. Tocopherols and tocotrienols play an important roles in the oxidative stability of vegetable oils and in the nutritional quality of crop plants for human and livestock diets. Here, we review major biosynthetic pathways, including common precursors and competitive pathways of the vitamin E and its derivatives in plants

Phenolic contents and in vitro antioxidant activity of four commonly consumed nuts in Algeria

This study was carried out to determine the phenolic contents and the antioxidant activity of four nuts with different solvent extract. Total phenolic compounds, flavonoids, and proanthocyanidin were quantified. Antioxidant activity was evaluated by various in vitro tests, including ferric reducing power, phosphomolybdenum method assay, and free radical scavenging activity. The results showed that the total phenolic contents varied between 0.30 g GAE/100 g (peanuts) and 1.65 g GAE/100 g (walnuts); the flavonoid contents varied between 0.17 g QE/100 g (peanuts) and 0.41 g QE/100 g (hazelnut). The phenolic contents of four nut extracts exhibit potent antioxidant activity. Indeed, walnuts were the richest in total phenolic content and demonstrated the highest potential for overall antioxidant capacity using ferric reducing power assay (FRP), phosphomolybdenum method assay, and free radical scavenging activity (FRSA). Phenolic amounts positively correlated with antioxidant activity tested

Effect of in vitro gastrointestinal digestion on antioxidant potential of three prickly pear variety extracts

The aim of this study was to evaluate the effect of in vitro gastrointestinal digestion on the phenolic amounts and their antioxidant potential of three prickly pear variety extracts. The total phenolic compounds (phenolic, flavonoid, and proanthocyanidin) contents were assessed as well as their antioxidant activities (total antioxidant capacity, ferric reducing power, and DPPH free radical scavenging activity) were evaluated before and after digestion. Our results showed that before digestion, the yellow variety possesses high phenolic and proanthocyanidin contents with values of 3176±18 mg GAE/100 g and 90.3±9.8 mg CE/100 g, respectively. However, the red variety has high flavonoids content with a value of 1638±6 mg QE/100 g. Antioxidant activities showed similar trend that phenolic compounds. During the digestion, the antioxidant potential of digested extracts decreased significantly (P<0.001) compared to undigested ones. Hence, this potential increased significantly (P<0.01) from the oral to the intestinal phases. The statistical analysis revealed a moderate correlation between phenolic compounds and antioxidant activity. Hence, IVGID affects the antioxidant potential of extracts, but pH and enzymatic changes do not affect their gut bioaccessibility

Bioactive Compounds, Physico-Chemical Characteristics, and Sensory Analysis of Biscuits Enriched with Saffron as Natural Colorant

Recently, the primary focus of the food industry lies in replacing synthetic additives with natural ones. Saffron (Crocus sativus) is an agricultural product used by agri-food industries as naturel colorant. The aim objective of the present work was to explore the application of Saffron (Crocus sativus) crocin extracts as natural colorant in biscuits. Furthermore, a comparative study was conducted to evaluate the performance of the cookies during 45 days of refrigerated storage. Physicochemical analysis was carried out on the biscuits prepared during storage. In addition, total phenolics, flavonoids, and crocins content was assessed. The free radical scavenging activity (DPPH) and ferric reducing power were also evaluated. All parameters studied were carried out after 15, 30, and 45 days of storage period. The obtained results indicate that the use of saffron in the manufacture of biscuits gives a product with a good physicochemical quality for a limited duration (45 days of storage). Indeed, the values of moisture content, pH, and acidity are in line with the cookie preparation standard. A variation in these values was recorded during storage. In addition, the saffron biscuit showed a high level of phenolics, flavonoids and condensed tannin contents with a strong antioxidant activity. A difference in phenolic compounds level and in the antioxidant activity during storage period was also recorded for the biscuits prepared with synthetic colorant and those without colorant. A natural additives offer a more convenient alternative for consumers who prefer food products without synthetic additives. Hence, the biscuits enriched with saffron as natural additives can be developed as functional food with healthy benefits

Elicitation of the defence mechanisms at plant case of Cucumis melo

The judicious use of elicitors could reduce the amount of pesticide necessary to protect crops and preservation of the environment. This strategy frequently called "stimulation of natural defenses" arouses more and more interest in the phytosanitary field

Assessment of antioxidant potential of phenolic compounds fractions of Algerian Ceratonia siliqua L. pods during ripening stages

The consecutive extraction via different solvents of increasing/decreasing polarity, which allowed a pre-fractionation of the extracted compounds, is widely used as major method for extraction of polyphenols. Thus, the phenolic compounds of Ceratonia siliqua L., at unripe and ripe stages, were extracted by four solvents of increasing polarity (hexane, chloroform, ethyl acetate, and acetone/water (70:30, v/v), consecutively. The extracts were evaluated for their total phenolic and flavonoid contents, while the antioxidant capacity was assessed in vitro using DPPH radical and hydrogen peroxide (H2O2) scavenging assays. The phenolic profile has been carried out by HPLC-MS/MS. The results showed that the phenolic contents and antioxidant capacity varied with the nature of extracts and the ripening stage. The 70% aqueous acetone and the ethyl acetate extracts contained the highest phenolic and flavonoid contents, and subsequently showed a pronounced scavenging activity on DPPH and hydrogen peroxide at unripe and ripe stages. The HPLC-MS/MS allowed the identification of five free phenolic acids (gallic, syringic, cinnamic, p-coumaric and ellagic acid for the first time) and five flavonoids (apigenin, naringenin, kaempferol, quercetin rhamnoside and myricetin rhamnoside) at both ripening stages

Effect of microencapsulation conditions on phenolic compounds and antioxidant activity of propolis using double emulsion solvent evaporation approach

The aim of this work was to microencapsulate propolis phenolic compounds using polycaprolactone as wall material by double emulsion solvent evaporation (w 1 /o/w 2) . Microencapsulation experiments were carried out by investigating the effect of sample/solvent ratio (10–100 mg mL −1 ), poly(ε-caprolactone) (PCL) concentrations (200–1,000 mg mL −1 ), poly(vinyl alcohol) (PVA) concentrations (0.5–2.5 g mL −1 ), and stirring speed (200–1,000 r.p.m.) on the microencapsulation efficiency of total phenolic content (TPC%) and antioxidant activity of propolis. The best microencapsulation conditions were selected according to the total phenolic amount and their antioxidant activity. Experimental results showed that all microencapsulation conditions had significant effects ( P < 0.05) on total phenolic content and antioxidant activities. The best conditions were: 30 mg mL −1 , 600 mg mL −1 , 2 g mL −1 , and 400 r.p.m. for sample/solvent ratio, PCL concentrations, PVA concentrations, and stirring speed, respectively, with values of 86.98 ± 0.03% for phenolic encapsulation efficiency, 53.81 ± 0.50% for free radical scavenging activity (DPPH), and 45,480 Trolox equivalent, mg TE/100 g dry weight for ferric reducing antioxidant power (FRAP). Under all encapsulation conditions, a significant positive correlation was observed between ferric reducing antioxidant power, free radical scavenging activity, and phenolic content

Optimisation of microencapsulation efficiency of propolis phenolic compounds by double emulsion method using response surface methodology

Abstract The aim of this study was to optimise the microencapsulation efficiency of propolis phenolic compounds by double emulsion solvent evaporation technique (W 1 /O/W 2 ). The solvent/sample ratio and the polymer and surfactant concentration parameters were optimised using response surface methodology (RSM) through Box–Behnken Design (BBD). For each parameter studied, total phenolic content encapsulation efficiency (TPCEE), free radical scavenging activity (DPPH), and ferric reducing antioxidant power (FRAP) were evaluated. The results showed that the optimal parameters were: 31.60 mg mL −1 for sample/solvent ratio, 606.28 mg mL −1 for poly(ε-caprolactone) (PCL) concentrations, and 2.05 g mL −1 for poly(vinyl alcohol) (PVA) concentration. The optimum values obtained were: 84.62% for encapsulation efficiency of phenolic content, 51.89% for DPPH, and 48,733 mg Trolox Equivalent/100 g dry weight for FRAP. The experimental checking of results revealed the validity of elaborated models and their suitability for the prediction of both responses. The developed mathematical models have expressed a high level of significance through RSM optimisation processes for phenolic antioxidants of propolis

Evaluation of the antimicrobial potential of digested and undigested carob phenolic extracts: Impact on selected gut microbiota

Carob pulp is a natural source of polyphenols, which have been shown to possess health benefits. These compounds play a crucial role in initiating, shaping, and modulating the gut microbiota. The objective of this study was to evaluate the impact of carob pulp phenolic extracts on nine specific groups of human gut microbiota before and after in vitro gastrointestinal digestion. The effects of pure gallic and coumaric acids were also tested. The results showed that the treated phenolic compounds exhibited inhibitory effects on the growth of most pathogenic bacteria. Gallic acid, in particular, demonstrated the most potent antimicrobial effect on Listeria monocytogenes , reducing its growth to below 5%. Staphylococcus aureus and Escherichia coli showed a growth reduction of up to 10%. Furthermore, both phenolic acids, before and after digestion, led to a slight reduction in E. coli O157:H7 numbers. Probiotic bacteria experienced minimal decrease following exposure to phenolic extracts. However, the growth of Lactobacillus casei ssp . rhamnosus was significantly inhibited by almost 50%. Interestingly, the in vitro digestion process exhibited a stronger antibacterial effect against pathogenic bacteria compared to probiotic bacteria. These results highlight the potential of carob phenolic extracts in modulating the intestinal microbiota, thereby offering interesting prospects for the development of diet-based health strategies