249
From the broad structural diversity of polyphenols, a wide variability of physicochemical properties can be expected. Therefore, the presentation of a unique and
general method for extracting and isolating these compounds is almost impossible.
This is also the reasons why polyphenol extraction still generates strong interest,
searching for efficient technologies and extractant media.
7.2.3 Antioxidant Properties
Polyphenols display a wide range of bio-physicochemical properties that derive
from their multi-phenolic structures. These properties have been thoroughly
reviewed in many publications (Manach et al. 2004; Cheynier 2005; BelščakCvitanović et al. 2018; Tanase et al. 2019). Polyphenols are essential for plant
growth and development. They have important roles in controlling their size
and their pigmentation, with a pivotal contribution in photosynthesis. They also
provide resistance to microbial pathogens (Treutter 2006) and herbivorous animals,
especially insects (Boulogne et al. 2012). The bitterness due to polyphenols also
discourages plant consumption. Polyphenols act as signaling molecules to distinguish symbionts, as UVB screens for protecting against solar radiation, hence preventing DNA damages. Finally, among many other properties, they promote some
beneficial interactions with other organisms.
However, their most acknowledged property is unquestionably antioxidative
action. Polyphenols are natural antioxidants, which are capable to directly scavenge
reactive oxygen species (ROS, i.e., O 2
•−
, OH
•
, H 2 O
−
, H 2 O
•
, etc.), nitrogen reactive
species (RNS, i.e., NO
•
, ONOO
−
, NO 2
•
, etc.), and other free radicals (RO
•
and ROO
•
)
that are derived from oxidation of low-density lipoproteins, proteins, and oligonucleic acids (DNA and RNA) (Li et al. 2000; Shi et al. 2000; Vaya et al. 2003; Manach
Scheme 7.1 General classes of polyphenols in plant (green), algae, and microalgae (blue).
Monophenolic acids, which belong to the “phenolic acids” group, are not polyphenols but are
generally present in the extracts
7 Extraction of Plant and Algal Polyphenols Using Eutectic Solvents
From the broad structural diversity of polyphenols, a wide variability of physicochemical properties can be expected. Therefore, the presentation of a unique and
general method for extracting and isolating these compounds is almost impossible.
This is also the reasons why polyphenol extraction still generates strong interest,
searching for efficient technologies and extractant media.
7.2.3 Antioxidant Properties
Polyphenols display a wide range of bio-physicochemical properties that derive
from their multi-phenolic structures. These properties have been thoroughly
reviewed in many publications (Manach et al. 2004; Cheynier 2005; BelščakCvitanović et al. 2018; Tanase et al. 2019). Polyphenols are essential for plant
growth and development. They have important roles in controlling their size
and their pigmentation, with a pivotal contribution in photosynthesis. They also
provide resistance to microbial pathogens (Treutter 2006) and herbivorous animals,
especially insects (Boulogne et al. 2012). The bitterness due to polyphenols also
discourages plant consumption. Polyphenols act as signaling molecules to distinguish symbionts, as UVB screens for protecting against solar radiation, hence preventing DNA damages. Finally, among many other properties, they promote some
beneficial interactions with other organisms.
However, their most acknowledged property is unquestionably antioxidative
action. Polyphenols are natural antioxidants, which are capable to directly scavenge
reactive oxygen species (ROS, i.e., O 2
•−
, OH
•
, H 2 O
−
, H 2 O
•
, etc.), nitrogen reactive
species (RNS, i.e., NO
•
, ONOO
−
, NO 2
•
, etc.), and other free radicals (RO
•
and ROO
•
)
that are derived from oxidation of low-density lipoproteins, proteins, and oligonucleic acids (DNA and RNA) (Li et al. 2000; Shi et al. 2000; Vaya et al. 2003; Manach
Scheme 7.1 General classes of polyphenols in plant (green), algae, and microalgae (blue).
Monophenolic acids, which belong to the “phenolic acids” group, are not polyphenols but are
generally present in the extracts
7 Extraction of Plant and Algal Polyphenols Using Eutectic Solvents