Application of Microbial-Synthesized Nanoparticles …
407
3.1.1 Antioxidants
An antioxidant is a substance described as a component that is added in small amounts
and slows/inhibits the autoxidation of oxidizable molecules (Cui et al. 2018). The
utilization of synthetic antioxidants in processed foods is wide, preventing the formation of free radicals. However, it is suggested that they can cause several diseases
like asthma, joint pain, dermatitis, and stomach and eye problems (Kumar et al.
2019). Nanoparticles can be utilized as nanoantioxidants becuase they have ability
to slow down the autoxidation overall rate, by trapping the carrying radicals, or
by decreasing the initiation of oxidative events (Valgimigli et al. 2018), presenting
strong and persistent interactions with biomolecules that are more effective against
free radical-induced damage (Sandhir et al. 2015).
Several metals present the nanoantioxidant properties (palladium, silver, platinum,
and gold), as well as some metal oxides, acting like catalase mimics (CAT-mimics), by
decomposing hydrogen peroxide into water and oxygen when in neutral or basic pH
values (Valgimigli et al. 2018). In acidic pH values, the prooxidant effect is observed
in a behavior similar to peroxidase enzymes, where HO· is released from hydrogen
peroxide in a Fenton-like reaction (Nosaka and Nosaka 2017). AgNPs biosynthesized
from plants like Cassia tora and Artocarpus altilis leaves, as well as from brown
algae Cystoseira trinodis displayed antioxidant activities (Saravanakumar et al. 2015;
Ravichandran et al. 2016; Gu et al. 2018). Similarly, AgNPs biosynthesized using
extracts of Cola nitida, Theobroma cacao, Synsepalum dulcificum, Hyptis suaveolens, Petiveria alliacea, and Chasmanthera dependens (Lateef et al. 2016c, d, e,
2018a, b,2020) have displayed potent antioxidant activities.
Silica is considered a biochemically inert compound, allowing its utilization for
the elaboration of food-grade nanoantioxidants, such as caffeic acid and gallic acid
(Valgimigli et al. 2018), as well as Citrus and Syzygium essential oils (Cui et al.
2017; Himed et al. 2019). Magnesium oxide nanoparticles are highly ionic particulates that presents high surface areas, unique optical, electronic, magnetic, thermal,
mechanical, and chemical properties due to its characteristic structures (Ravishankar
and Jamuna 2011; Ramanujam and Sundrarajan 2014). Dobrucka (2016) studied
the biosynthesis of nanoantioxidant particles using aqueous extract of Artemisia
abrotanum in the neutralization of DPPH (2,2-diphenyl-1-picrylhydrazyl) radical,
in different solution ranges, while Sharmila et al. (2019) evaluated the nanoantioxidant activity of MgO using Pisonia alba leaf extract, assessed for its free radical
scavenging activity and reducing power activity.
Some polyphenols have also been utilized as strong antioxidants, neutralizing the
free radicals by direct scavenging or quenching of oxygen free radicals and inhibition
of oxidative enzymes that generate reactive oxygen species (Jana et al. 2017). Palacio
et al. (2020) studied the encapsulation of three polyphenols, epigallocatechin-3gallate (EGCG), propyl gallate (PG), and gallic acid (GA), using an ionic crosslinking method on succinyl-chitosan nanoparticles for the evaluation of the drug
encapsulation efficiency and loading capacity.
407
3.1.1 Antioxidants
An antioxidant is a substance described as a component that is added in small amounts
and slows/inhibits the autoxidation of oxidizable molecules (Cui et al. 2018). The
utilization of synthetic antioxidants in processed foods is wide, preventing the formation of free radicals. However, it is suggested that they can cause several diseases
like asthma, joint pain, dermatitis, and stomach and eye problems (Kumar et al.
2019). Nanoparticles can be utilized as nanoantioxidants becuase they have ability
to slow down the autoxidation overall rate, by trapping the carrying radicals, or
by decreasing the initiation of oxidative events (Valgimigli et al. 2018), presenting
strong and persistent interactions with biomolecules that are more effective against
free radical-induced damage (Sandhir et al. 2015).
Several metals present the nanoantioxidant properties (palladium, silver, platinum,
and gold), as well as some metal oxides, acting like catalase mimics (CAT-mimics), by
decomposing hydrogen peroxide into water and oxygen when in neutral or basic pH
values (Valgimigli et al. 2018). In acidic pH values, the prooxidant effect is observed
in a behavior similar to peroxidase enzymes, where HO· is released from hydrogen
peroxide in a Fenton-like reaction (Nosaka and Nosaka 2017). AgNPs biosynthesized
from plants like Cassia tora and Artocarpus altilis leaves, as well as from brown
algae Cystoseira trinodis displayed antioxidant activities (Saravanakumar et al. 2015;
Ravichandran et al. 2016; Gu et al. 2018). Similarly, AgNPs biosynthesized using
extracts of Cola nitida, Theobroma cacao, Synsepalum dulcificum, Hyptis suaveolens, Petiveria alliacea, and Chasmanthera dependens (Lateef et al. 2016c, d, e,
2018a, b,2020) have displayed potent antioxidant activities.
Silica is considered a biochemically inert compound, allowing its utilization for
the elaboration of food-grade nanoantioxidants, such as caffeic acid and gallic acid
(Valgimigli et al. 2018), as well as Citrus and Syzygium essential oils (Cui et al.
2017; Himed et al. 2019). Magnesium oxide nanoparticles are highly ionic particulates that presents high surface areas, unique optical, electronic, magnetic, thermal,
mechanical, and chemical properties due to its characteristic structures (Ravishankar
and Jamuna 2011; Ramanujam and Sundrarajan 2014). Dobrucka (2016) studied
the biosynthesis of nanoantioxidant particles using aqueous extract of Artemisia
abrotanum in the neutralization of DPPH (2,2-diphenyl-1-picrylhydrazyl) radical,
in different solution ranges, while Sharmila et al. (2019) evaluated the nanoantioxidant activity of MgO using Pisonia alba leaf extract, assessed for its free radical
scavenging activity and reducing power activity.
Some polyphenols have also been utilized as strong antioxidants, neutralizing the
free radicals by direct scavenging or quenching of oxygen free radicals and inhibition
of oxidative enzymes that generate reactive oxygen species (Jana et al. 2017). Palacio
et al. (2020) studied the encapsulation of three polyphenols, epigallocatechin-3gallate (EGCG), propyl gallate (PG), and gallic acid (GA), using an ionic crosslinking method on succinyl-chitosan nanoparticles for the evaluation of the drug
encapsulation efficiency and loading capacity.