''Lessonia nigrescens'', the grey weed or giant grey weed, is a South American kelp species in the genus ''
Lessonia''.
There is at least two populations of the seaweed, marked by the difference in phenolic content. There is a subtidal population with higher phenol content and an intertidal population with a lighter phenol content. The difference in the phenolic content can be explained by the herbivory selection pressure due to the sea snail ''
Tegula tridentata''.
UV treatment induces the production of
phlorotannin
Phlorotannins are a type of tannins found in brown algae such as kelps and rockweeds or sargassacean species, and in a lower amount also in some red algae. Contrary to hydrolysable or condensed tannins, these compounds are oligomers of phlorog ...
s that accumulate in
physodes.
This weed contains the phytosterol
saringosterol that shows an inhibitory effect on ''
Mycobacterium tuberculosis'' growth.
[Inhibition of Mycobacterium tuberculosis growth by saringosterol from Lessonia nigrescens. Wächter Gerald A, Franzblau Scott G, Montenegro Gloria, Hoffmann Joseph J, Maiese William M and Timmermann Barbara N, Journal of Natural Products, 2001, volume 64, number 11, pages 1463-1464, ]
References
External links
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algaebase.org
Species described in 1826
nigrescens
{{Phaeophyceae-stub