Natural products as inhibitors of ChC and elastase
Secondary metabolites and whole extracts from plants
have been widely investigated and found to have anti-collagenase
and anti-elastase activities. Plants contain a wide
variety of compounds including polyphenols such as flavonoids,
tocopherols, phenolic acids and tannins which
have been found to provide ChC inhibitory compounds
or a platform on which to synthesize active molecules.
Isolated green tea (Camellia sinensis) polyphenols such as
catechin and epigallocatechin gallate (EGCG) have been
found to be inhibitors of collagenase and elastase [10].
These are powerful bioflavonoids with strong anti-oxidant
activity Aloe gel constituents (aloins) have also been
isolated from Aloe vera (Aloe barbadensis) and have been
found to show inhibition of collagenase in vitro [16]. Triterpenoids
known as boswellic acids isolated from frankincense
(Boswellia spp.) resin have also been shown to have
anti-elastase activity [14]. In one study, 150 plant extracts
were tested for their ability to inhibit elastase in which six
plants showed activity over 65%. These included cinnamon
(Cinnamonum cassia), turmeric (Curcuma longa) and
nutmeg (Myristica fragrans) [17]. Polyphenols isolated
from persimmon (Diospyros kaki) leaf showed anti-collagenolytic
and anti-elastase activity [18]. This activity was
thought to be due to the flavonoids present in the
polyphenol extract. Extracts from Rosemary (Rosmarinus
officinalis) have also been found to have good anti-elastase
activity using spectrophotometric analysis [13]. Plant
extracts and natural products which have shown activity
in these assays represent a wide variety of the types of phenolic
compounds found in higher plants.