132
J. Pospíšil et al.
possibly they also can protect neurons against the neurotoxic effects of β-amyloid
protein accumulation. However, in these cases, such effects have not been proven
[118–122]. Honokiol (42) (a neolignan extracted from species of the genus Magnolia)
also possesses CNS-protective activity. Honokiol is found in a number of traditional
Chinese medicine preparations that are utilized for their beneficial effects. In the case
of neuroprotective activity, it is considered that the protective properties of honokiol
(42) result from the inhibition of prostaglandin E2 production in the brain [123–125].
In addition, compound 42 is also a suppressor of proinflammatory cytokines, which
influence the oxidative damage of tissues, and exhibits antiviral properties (against
dengue virus type 2), and also has antitumor potential and improves learning abilities
and memory damage in mice [126, 127].
3.3.2 Antioxidative Activity
It has been known for some time that reactive oxygen species (ROS) have a harmful
impact on cells, since they cause structural or functional damage to lipids, proteins, or
nucleic acids [128, 129]. Phenylpropanoids [130, 131] and other plant phenols [132]
behave as strong antioxidants with the ability to transform a wide range of reactive
chlorine, nitrogen, or oxygen radical species to harmless atoms and functional groups.
In addition, they are also strong chelating agents with the propensity of chelating
various metal ions. Thus, it seems logical that they could be used in a protective
capacity (e.g., as nutritional supplements), with the aim of retarding or suppressing
age-related degenerative diseases. It should be pointed out, however, that the real
impact of such compounds on age-related degenerative illnesses is so far speculative,
since none of the studies focused on this topic is conclusive [133, 134]. It was also
suggested that ROS play a key role in various mechanisms that lead to nephropathy
[135]. Some scientific studies have produced indirect evidence that phenylpropanoids
and especially more complex phenolic compounds could play an important role in
diminishing the quantities of ROS in the human body [136, 137].
Resveratrol (31) (Fig. 7), a stilbene-type phenolic compound, possesses antiinflammatory, antioxidative, antiaging, and antidiabetic effects, among other biological activities. In terms of its mechanism of action, it has been observed that 31
acts as NAD-dependent deacetylase sirtuin-1 activator and also is an activator of
various antioxidant enzymes via interacting with the nuclear factor erythroid 2-(Nrf2)- Kelch-like ECH-associated protein 1 (Keap1) [138, 139]. In addition, 31 can
modulate nuclear factor kappa-B (NF-κB), nitric oxide synthase (iNOS), and inhibit
cyclooxygenase [138, 139]. Moreover, it was observed that 31 may decrease the
risk of proteinuria, hypoalbuminemia, and hyperlipidemia [138, 139]. However, for
these activities, the mechanism of action in each case is not clear. Accordingly, it
is apparent that 31 “interacts” in the human body in many ways. To summarize its
type of activity, a comprehensive list of the effects of 31 is provided according to
the tissue where it acts, or in the case of cardiovascular prevention, according to the
manner it is believed to act (Fig. 8) [140–144].
J. Pospíšil et al.
possibly they also can protect neurons against the neurotoxic effects of β-amyloid
protein accumulation. However, in these cases, such effects have not been proven
[118–122]. Honokiol (42) (a neolignan extracted from species of the genus Magnolia)
also possesses CNS-protective activity. Honokiol is found in a number of traditional
Chinese medicine preparations that are utilized for their beneficial effects. In the case
of neuroprotective activity, it is considered that the protective properties of honokiol
(42) result from the inhibition of prostaglandin E2 production in the brain [123–125].
In addition, compound 42 is also a suppressor of proinflammatory cytokines, which
influence the oxidative damage of tissues, and exhibits antiviral properties (against
dengue virus type 2), and also has antitumor potential and improves learning abilities
and memory damage in mice [126, 127].
3.3.2 Antioxidative Activity
It has been known for some time that reactive oxygen species (ROS) have a harmful
impact on cells, since they cause structural or functional damage to lipids, proteins, or
nucleic acids [128, 129]. Phenylpropanoids [130, 131] and other plant phenols [132]
behave as strong antioxidants with the ability to transform a wide range of reactive
chlorine, nitrogen, or oxygen radical species to harmless atoms and functional groups.
In addition, they are also strong chelating agents with the propensity of chelating
various metal ions. Thus, it seems logical that they could be used in a protective
capacity (e.g., as nutritional supplements), with the aim of retarding or suppressing
age-related degenerative diseases. It should be pointed out, however, that the real
impact of such compounds on age-related degenerative illnesses is so far speculative,
since none of the studies focused on this topic is conclusive [133, 134]. It was also
suggested that ROS play a key role in various mechanisms that lead to nephropathy
[135]. Some scientific studies have produced indirect evidence that phenylpropanoids
and especially more complex phenolic compounds could play an important role in
diminishing the quantities of ROS in the human body [136, 137].
Resveratrol (31) (Fig. 7), a stilbene-type phenolic compound, possesses antiinflammatory, antioxidative, antiaging, and antidiabetic effects, among other biological activities. In terms of its mechanism of action, it has been observed that 31
acts as NAD-dependent deacetylase sirtuin-1 activator and also is an activator of
various antioxidant enzymes via interacting with the nuclear factor erythroid 2-(Nrf2)- Kelch-like ECH-associated protein 1 (Keap1) [138, 139]. In addition, 31 can
modulate nuclear factor kappa-B (NF-κB), nitric oxide synthase (iNOS), and inhibit
cyclooxygenase [138, 139]. Moreover, it was observed that 31 may decrease the
risk of proteinuria, hypoalbuminemia, and hyperlipidemia [138, 139]. However, for
these activities, the mechanism of action in each case is not clear. Accordingly, it
is apparent that 31 “interacts” in the human body in many ways. To summarize its
type of activity, a comprehensive list of the effects of 31 is provided according to
the tissue where it acts, or in the case of cardiovascular prevention, according to the
manner it is believed to act (Fig. 8) [140–144].