 |
| Mimosa pudica flower - Location: Malifa, Samoa |
Mimosa pudica is a plant that is no doubt easily
recognised by former students of Samoa College and other schools in Samoa as it
was (and still is) often a requirement for those on detention or hard labour to
weed them as punishment. Among its
common/vernacular names in English are the names Sensitive plant and Sleeping grass due
to the way its leaves fold up when it is disturbed.
 |
| Mimosa pudica - Location: Malifa, Samoa |
Mimosa pudica is
a common plant in Samoa where it is referred to as Vao fefe
(which literally translates as “frightened grass” or “grass that is afraid”) and
is found throughout the Pacific although it originates from tropical America. Its close relative Mimosa invisa
commonly known in English as Giant sensitive plant or vao fefe
pālagi in Samoan is probably remembered with even less
fondness by those who during the School Clean Up Days following long holidays have
had to deal with cutting it and/or gathering it up for disposal, for while Mimosa pudica is a sprawling
plant that spreads out flat on the ground and can be relatively easily pulled
up (with care) by the root, its giant relative is a real nasty customer that
sprawls out in a scrambling manner and can cover large areas up with tangles of
long windy stems.
 |
| Mimosa invisa - Location: Malifa, Samoa |
To make things
worse Mimosa invisa has rather nasty little barb-like
prickles that come off and become embedded in the skin. Not only that but their
long flexible stems can wrap themselves around the limbs of the unwary or
careless leaving behind a multitude of these vicious prickles embedded in the
skin as well as equally painful and nasty scratches. From personal experience and observation both
types of injuries need to be treated seriously (with attention to removal of
all thorns and careful disinfection of the scratches and punctures) as they can
easily become infected without proper care especially in tropical climates.
 |
| Mimosa invisa - Close up of thorns |
Finding and
removing Mimosa
invisa while they are
still seedlings popping up in newly disturbed or recently cleared areas is the
best course of action as it saves hours of painful work later if they are
allowed to grow and proliferate.
Mimosa pudica on the other hand has bigger thorns which
rarely get detached. The main source of injury associated with them is from
walking on them barefoot or while trying to pull them up. The trick to pulling
them up is to carefully lift the branching stems up to locate the main stem,
then carefully wrapping the rest up in a handy piece of cardboard or cloth (we
did not get gloves to do this), then firmly grasping the whole you pull up the
tap root.
For those on
detention or hard labour if they had a certain number to pull up some
enterprising types apparently then carefully splitting the plant up so that
each separate part branching off from the central stem had a sliver of the tap
root to pass off as separate plants. Of course with a vigilant prefect standing
guard that was not always possible. In any case most of us just got told to
weed an area and it did not matter how many of these were pulled up.
 |
| Mimosa pudica - Close up of thorns |
Both plants belong
to the Genus Mimosa which is part of the
Plant Family: Fabaceae (also
known as the Legume, Bean or Pea Family).
Nitrogen fixing
Like other
members of Fabaceae it
can form root nodules that are inhabited by nitrogen fixing bacteria. Various
members of Fabaceae have long been used in agriculture
as green manure. However, I do not foresee anyone growing Mimosa pudica for its nitrogen fixing properties given
how many other less problematic or prickly relatives it has that can be used
for that purpose. On the other hand perhaps there may be a future for growing
it for its other properties.
Although some
sources indicate that Mimosa
invisa has been used
as fodder for cattle the very thought of cattle eating those vicious looking
stems coated as they are with thorns is an unpleasant image at the least.
Miosine
The interesting
thing about Mimosa
pudica aside from the
bizarre fact (to those who have had to weed it as punishment or to get it out
of their own lawns, gardens or crops) that in some countries it is actually
grown and sold as a curiosity (for the way its leaves fold up when disturbed) is
that scientific research has discovered that its roots contain a plant amino
acid, mimosine which causes cell apoptosis or cell death. That is
it mimosine
triggers the mechanism in cells that causes the cell to stop growing and proliferating
and leads to it dying. Hence “cell death”
Apoptotic and antiproliferative and effects of
Miosine
Now the really
interesting and promising thing about the discovery of such naturally occurring molecules is the implication for cancer research and the
treatment of cancer, in particular a less invasive, less toxic and less gruelling
treatment than currently available using surgery and chemotherapy.
The discovery
came about through the linking of several prior studies which led to the
question as to possible application in cancer treatment. Basically the two core
bits of information drawn from earlier studies upon which the study based its
hypothesis were:
Firstly the
knowledge that iron played a vital role in cell proliferation (which is the
core problem with cancer tumours, i.e. uncontrolled growth of the tumour as
well as metastasis or spreading of these cancerous cells to
other areas of the body). A horticultural analogy of metastasis it would a fungus growing and then sending out spores which is
pretty much what happens when cancerous cells from a tumour spread through the
body through the blood stream after penetrating the walls of lymphatic and/or
blood vessels.
Apparently
earlier scientific studies on Mimosa
pudica had shown that
mimosine
had a anti-proliferative
and apoptotic effects in certain cultured cells by blocking the absorption of
iron.
For those interested here is the
link and reference to the study
What medical
scientists are looking into is the possibility of extracting or perhaps
synthesising mimosine
which could then be introduced into the cancer cells of patients to trigger the
death of the cancer cells. It would be like sending James Bond to infiltrate
the top secret base of some arch villain to push the self destruct button on the
villain’s latest weapon of mass destruction and world domination.
Other scientific
studies on Mimosa
pudica showed that aqueous
ethanol extracts of its leaves had antiproliferative and apoptotic effects.
Immobilising effect on stercoralis filariform
larvae
A Jamaican
scientific study which looked at the effects of plant extracts found that aqueous
ethanol extracts from Mimosa
pudica leaves immobilised
the stercoralis
filariform larvae. Five other plant extracts were tested as well as
three commercially available drugs; albendazole,
thiabendazole and levamisole. In the study, the extract from green leaves of Mimosa pudica and
the drug levamisole were the quickest to affect the larvae, immobilising
them in under one hour.
For those interested here is the
link and reference to study
http://www.ncbi.nlm.nih.gov/pubmed/2082565
Strongyloides stercoralis is a small ground dwelling nematode (roundworm) that can cause a chronic
infection called Strongyloidiasis in baboons and chimpanzees as well as humans
when they become infected by this intestinal parasite.
Note:
Apparently in the US it is known as threadworm while in the UK it is referred
to as pinworm since in the UK the term threadworm refers to nematodes of
another genus. (I have not been able to discern what it is called in other
English speaking countries but would suspect that Commonwealth states would
most likely use the United Kingdom term).
Apparently the
life cycle of Strongyloides
stercoralis is both complex and unique among intestinal nematodes
because it alternates between free-living and parasitic cycles as well as its
ability for autoinfection and multiplying within the host which not only
increases its success as an organism but poses certain challenges in treating
those infected. This is because current treatment only affects certain forms of
the parasite at certain stages of its life cycle. Since it is able to auto
infects host and reproduce in the host this means that the treatment is lengthy
in order to eradicate the parasite completely.
The discovery
that mimosine is able to immobilise the stercoralis filariform larvae may
therefore have practical applications although it is not clear as to its
effectiveness against other forms of the parasite.
Another issue
regarding the potential for its use in treating this parasitic disease is that
the existing drugs can have negative side effects which the mimosine extract
might not have. (NB. No human studies appear to have been done yet).
To be continued in Part 2:
Other scientific studies on potential medical use of Mimosa
Use of Mimosa pudica in Traditional Medicine
Modern Medical use and scientific studeis
Other uses of Mimosa pudica
Scientific / Binomial Name: Mimosa pudica
Vernacular / Common names:
English: Sensitive Plant, sleeping grass,
humble plant, touch-me-not, shameful plant, ant-plant
Samoan: vao fefe, Tongan: mateloi,
Tahitian: pohe ha’avare, Fijian: co
gadrogadro
Portuguese: não-me-toque (touch-me-not),
sensitiva (sensitive) or dormideira (roughly "sleeper")
Spanish:
morí-viví or moriviví
Indonesian: putri-malu
Belongs to the Fafaceae Family, (Pea
Family)
Binomial
Name: Mimosa invisa
Common
names: Giant Sensitive Plant, sleeping grass, vao
fefe palagi (Samoa)
Taxonomy
- Family: Fabaceae – Genus: Mimosa –
Species: Mimosa púdica
- Family: Fabaceae – Genus: Mimosa –
Species: Mimosa invisa
- Family:– Genus: Strongyloides – Species: Strongyloides
stercoralis
- Family:– Genus:Naja –
Species: Naja kaouthia
Flora and Fauna - Plants and Critters Blog by
Vincent Albert Vermeulen is
licensed under a
Creative
Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.
Based on a work at
http://plantsandcritters.blogspot.be/.
Permissions beyond the scope of this license may be available at
http://plantsandcritters.blogspot.be/.
My other blogs
· Flora
and Fauna - Plants and Critters (on plants, animals as well as
gardening, conservation and environmental matters):
http://plantsandcritters.blogspot.com/
· The
Blood of Souls (language, translation and etymology) :
http://thebloodofsouls.blogspot.com/
· Whiskers
on Kittens (Life with Kittens and Cats in general) :
http://whiskersonkittens-vincent.blogspot.com/
References books
Whistler, W. Arthur, “Wayside Plants of the
Islands. A Guide to the Lowland Flora of the Pacific Islands including Hawai’i
Samoa Tonga Tahiti Fiji Guam Belau”, Isle Botanica, Honolulu, 1995.
ISBN 0-9645426-0-9
Reference
online sources:
Robinson RD, Williams
LA, Lindo JF, Terry SI, Mansingh A (1990). "Inactivation of strongyloides
stercoralis filariform larvae in vitro by six Jamaican plant extracts and three
commercial anthelmintics". West Indian Medical Journal 39
(4): 213–217. PMID 2082565.
http://www.ncbi.nlm.nih.gov/pubmed/2082565
