Centella (Centella asiatica): The famous wild vegetable of Asia
Wild vegetable: Centella asiatica
Centella asiatica juice used in Vietnam
Classification
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Centella asiatica
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The names
Classificational name: Centella
asiatica (L.) Urban.
Common name: Centella.
Regional names:
-Hindi: Brahmi
booti.
-Chinese: Luei gong gen meaning "chipped big bowl", literally
"thunder god's root".
-Tamil: Vallaarai.
-Sri Lanka
-Filipino:Takip-kohol.
-Vietnamese: Rau má (mother vegetable).
-Philippinean:
Yahong yahong.
-In India ,
it is popularly known by a variety of names: bemgsag, brahma manduki, brahmanduki,
brahmi, ondelaga or ekpanni (south
India , west India ), sarswathi aku (Andhra Pradesh), gotu
kola, khulakhudi, mandukparni, mandookaparni, or thankuni (Bengal ),
depending on region.
Distribution
Centella asiatica, commonly centella is a small, herbaceous, annual plant of the family Mackinlayaceae or subfamily Mackinlayoideae of family
Apiaceae, and is native to India , Sri Lanka , northern Australia , Indonesia , Iran ,
Malaysia , Melanesia , Papua
New Guinea , Vietnam
and other parts of Asia . It is used as a famous wild vegetable and as a medicinal herb in Ayurvedic
medicine, traditional African
medicine, and traditional Chinese
medicine. Botanical synonyms include Hydrocotyle asiatica L. and Trisanthus cochinchinensis (Lour.).
Description
The stems are slender, creeping stolons, green to reddish-green in
color, connecting plants to each other. It has long-stalked, green, reniform leaves with rounded apices which have smooth
texture with palmately netted veins. The leaves are borne on pericladial
petioles, around 2 cm. The rootstock consists of rhizomes, growing vertically down.
They are creamish in color and covered with root hairs.
The flowers are pinkish to red in color, born in
small, rounded bunches (umbels) near the surface of the soil. Each flower is
partly enclosed in two green bracts. The hermaphrodite flowers are minute in
size (less than 3 mm), with 5-6 corolla lobes per flower. Each flower
bears five stamens and two styles.
The fruit are densely reticulate, distinguishing it from species of Hydrocotyle
which have smooth, ribbed or warty fruit.
The crop matures in three months, and
the whole plant, including the roots, is harvested manually.
Habitat
Centella grows
along ditches and in low, wet areas. In Indian and Southeast Asian centella,
the plant frequently suffers from high levels of bacterial contamination,
possibly from having been harvested from sewage ditches. Because the plant is
aquatic, it is especially sensitive to pollutants in the water, which are easily
incorporated into the plant.
Culinary use
Centella is used as a leafy green in
Sri Lankan cuisine, where it is called gotu
kola. In Sinhalese gotu is translated as "conical
shape" and kola as "leaf". It is most often
prepared as malluma , a traditional accompaniment to rice and
curry, and goes especially well with vegetarian dishes, such as dhal, and jackfruit or pumpkin curry. It is considered quite
nutritious. In addition to finely chopped gotu
kola, malluma almost always contains grated coconut, and may also contain finely
chopped green chilis, chili powder, turmeric powder and lime (or lemon) juice. A variation of the
nutritious porridge known as kola
kenda is also made with gotu kola by the Sinhalese people of Sri Lanka
In Indonesia , the leaves are used for sambai oi peuga-ga, an Aceh type
of salad, and is also mixed into asinan in Bogor
In Vietnam and Thailand Bangkok
In Malay
cuisine the leaves of this plant
are used for ulam, a type of
Malay salad.
It is one of the constituents of the
Indian summer drink thandaayyee.
Medicinal effects
Centella is a mild adaptogen, is mildly antibacterial, antiviral, anti-inflammatory, antiulcerogenic, anxiolytic, nervine and vulnerary, and
can act as a a cerebral tonic, a circulatory stimulant, and a diuretic.
Centella asiatica may
be useful in the treatment of anxiety, and may be
a promising anxiolytic agent in the future.
In Thailand
Richard Lucas claimed in a book
published in 1966 (second edition in 1979) that a subspecies "Hydrocotyle
asiatica minor" allegedly from Sri Lanka also called fo ti tieng, contained a longevity
factor called 'youth Vitamin X' said to be 'a tonic for the brain and endocrine
glands' and maintained that extracts of the plant help circulation and skin
problems. However according to medicinal herbalist Michael Moore, it appears
that there is no such subspecies and no Vitamin X is known to exist.
Several scientific reports have
documented Centella asiatica's
ability to aid wound healing which is responsible for its traditional use in
leprosy. Upon treatment with Centella
asiatica, maturation of the scar is stimulated by the production of type I
collagen. The treatment also results in a marked decrease in inflammatory
reaction and myofibroblast production.
The isolated steroids from the plant
also have been used to treat leprosy. In
addition, preliminary evidence suggests that it may have nootropic effects. Centella asiatica is used to revitalize the brain and
nervous system, increase attention span and concentration, and combat aging.
Centella asiatica also has
antioxidant properties. It works for venous insufficiency. It is used in Thailand
Followers of Sri Sri Thakur Anukulchandra, commonly known
as Satsangees, all over the world take one or two fresh leaves with plenty of
water in the morning after morning rituals. This is prescribed by Sri Sri
Thakur himself.
'Many reports show the medicinal
properties of C. asiatica extract in a wide range of disease
conditions, such as diabetic microangiopathy, edema, venous hypertension, and
venous insufficiency. The role of C.
asiatica extract in the
treatment of memory enhancement and other neurodegenerative disorders is also
well documented. The first report concerning the antitumor property of C.
asiatica extract was on its
growth inhibitory effects on the development of solid and ascites tumors, which
lead to increased life span of tumor-bearing mice. The authors also suggested
the extract directly impeded the DNA synthesis. "In our study, C. asiatica
extract showed an obvious dose dependent inhibition of cell proliferation in
breast cancer cells.
New pharmacology studies
-Constituents: The purported active components of gotu kola (Centella
asiatica), accounting for 1-8% of the constituents, include
asiatic acid, madecassic acid, asiaticoside, asiaticoside A, and asiaticoside
B.The leaves of Centella
asiatica have also
been reported to contain 170mg calcium, 30mg phosphorous, 3.1mg iron, 414mg
potassium, 6.58mg beta-carotene, 0.15mg thiamine, 0.14mg riboflavin, 1.2mg
niacin, and 4mg asorbic acid.
-Alzheimer's disease effects: Asiaticoside derivatives, including asiatic acid and
asiaticoside 6, were shown to reduce hydrogen peroxide-induced cell death, decrease
free radical concentrations, and inhibit beta amyloid cell death in vitro, suggesting a
possible role for gotu kola in the treatment and prevention of Alzheimer's
disease and beta amyloid toxicity.
-Antioxidant effects: Asiaticoside derivatives, including asiatic acid and
asiaticoside 6, were shown to reduce hydrogen peroxide-induced cell death,
decrease free radical concentrations, and inhibit beta amyloid cell death in vitro, suggesting a
possible role for gotu kola in the treatment and prevention of Alzheimer's
disease and beta amyloid toxicity.
-Anti-gastric ulcer activity: In rats, extract of Centella
asiatica significantly
inhibited gastric ulceration induced by cold and resistant stress, similar to
the inhibition caused by famotidine and sodium valproate.The titrated extract
of Centella asiatica (TECA) has been shown to have
protective and therapeutic effects on gastric mucosal damage in rats. Fresh
juice of Centella asiatica given in doses of 200 or
600mg/kg twice daily for five days was shown to have protective activity
against gastric ulcers induced by ethanol, aspirin, cold-restraint stress, and
pyloric ligation.7 The
higher dose resulted in significantly increased mucin secretion and mucous
formation, while significantly decreasing cell shedding.
-Anti-inflammatory effects: In rats, Madecassol was shown to decrease the severity of
radiation-induced dermatitis vs. control.
-Anti-fertility effects: Animal study shows a consistent reduction of fertility in
female mice after the ingestion of isothankuniside and its derivative BK
compound, both of which are isolated from Centella
asiatica.
-Antimicrobial effects: An in
vitro study of Centella asiatica powder found no activity
against the acid-fastness or viability of M. tuberculosis, despite
its use in the treatment of leprosy (M. leprae). A subsequent in vitro study found asiaticoside to
have little microbicidal activity against M. tuberculosis or M. leprae; however, when
incorporated into liposomal form, the microbicidal activity of asiaticoside was
greatly increased. Centella asiatica extract
and asiaticoside are active against herpes simplex virus in vitro.
-Antineoplastic effects: In vitro, partially
purified fractions of Centella
asiatica crude
extract significantly inhibit proliferation of cancerous cells in a
dose-dependent fashion, with no toxic effects to human lymphocytes. In mice,
oral administration of both crude extract ofCentella asiatica and partially purified fractions
of the crude extract slow the development of solid and ascites tumors, and
increase the lifespan of mice, with possible action directly on DNA synthesis.
-Anxiolytic properties: Bradwejn et al. performed
a double-blind, placebo controlled trial to study the effects of gotu kola on
acoustic startle response (ASR), a validated instrument used to measure levels
of anxiety. At 30 and 60 minutes after intervention, subjects who consumed 12g
dose of gotu kola (from crude herb capsules, Nature's Way Canada, Ltd.) mixed
in 300ml of grape juice experienced a significant decrease in their ASR,
suggesting the possible ability of gotu kola to decrease anxiety. The small
sample size and use of healthy (non-anxious) subjects limit the application of
these data, but do suggest that gotu kola may possess anxiolytic properties.
Although gotu kola has been studied for anxiety, the exact mechanism of action
remains unclear.
-Cardiovascular effects: In an investigation of
oral Centellase (TTFCA 60mg three times daily) to stabilize carotid plaques, it
was reported that TTFCA regulated and modulated collagen production over the
12-month study period.
-Hepatic effects: A randomized controlled
trial showed that a combination product (CognoBlend® containing Bacopa monneria, Gingko biloba, cat's claw,
gotu kola, rosemary) may be an effective adjunct treatment for patients with
liver cirrhosis, although a mechanism of synergistic action in this study is
unclear.
-Hepatic effects (hepatotoxicity): Researchers have
hypothesized that gotu kola may contain di- or triterpenic active principles,
which can produce hepatic injury by promoting apoptosis and altering cell
membranes.
-Neuroprotective effects: The effect of chloroform:
methanolic (80:20) extract of Centella
asiatica (CA; 100 and
200mg/kg), was evaluated on the course of free radical generation and
excitotoxicity in monosodiumglutamate (MSG) treated female Sprague Dawley rats.
The extract showed significant improvement in catalase, super oxide desmutase,
and lipid peroxides levels in hippocampus and striatum regions. Glutathione
level was not altered with CA treatment. Similar observation was made with
dextromethorphan. The general behavior, locomotor activity, and CAl
-Vascular effects: A controlled study in 21 subjects with postphlebitic limbs
or lymphedema reports that daily Centellase (TTFCA) causes a significant
decrease in both the lymphatic/plasma protein concentration ratio and distal
edema. The total triterpenic fraction ofCentella asiatica (TTFCA) has been noted to
reduce ankle edema, foot swelling, and capillary filtration rate, as well as to
improve microcirulatory parameters (including resting flux, venoarteriolar
response, PO2, PCO2) in subjects with reported venous insufficiency
of the lower extremities. HU300 (containing 17.5mg of total triterpenoids
derived from Centella
asiatica), two tablets twice daily, is reported to decrease venous
distensibility index, reduce venous congestion, and reduce supine venous
pressure after eight months in subjects with venous insufficiency, deep vein
thrombosis, or perimalleolar leg ulcers.
-Wound/burn healing effects: Asiatic acid, madecassic
acid, and asiaticoside have been shown to stimulate the in vitro synthesis of collagen, both
alone and in combination.The titrated extract of Centella asiatica (TECA), asiatic acid, and
asiaticoside were shown to increase remodeling of a wound collagen matrix after
injection into an animal model, through the stimulation of both collagen and
glycosaminoglycan synthesis. Asiaticoside isolated from Centella asiatica increased hydroxyproline
content, tensile strength, and collagen content of wounds after topical administration
in an animal model. Asiaticoside was found to promote angiogenesis in chick
chorioallantoic membranes in
vitro.The application of topical 0.2% asiaticoside twice daily for seven
days to cutaneous wounds in rats led to increased wound levels of antioxidants
(superoxide dismutase, catalase, glutathione peroxidase, vitamin E, and
ascorbic acid) and decreased lipid peroxide levels. Increased cellular proliferation
and collagen synthesis was observed at wound sites after treatment with topical
or oral extract of Centella
asiatica in rats. An animal
study found that application of topical Centella
asiatica extract three times
daily for 24 days to open wounds resulted in increased collagen content and
tensile strength. An in vitro
study of the effects of total triterpenoid fraction of Centella asiatica (TTFCA) on human skin
fibroblasts found the extract to have no significant effect on cell
proliferation, total protein synthesis, or proteoglycan synthesis; however, a
significant increase in the percentage of collagen and cell layer fibronectin
was observed. Asiaticoside was found to cause a dose-related increase in
tensile strength after intramuscular administration of asiaticoside.
-Madecassol, an asiaticoside containing compound, inhibited
the biosynthesis of acid mucopolysaccharides and collagens in an animal
granuloma model. Madecassol also inhibited the proliferation of human embryo
fibroblasts in vitro.
Pharmacodynamics/Kinetics
-Absorption: An animal study found that
madecassoside, asiaticoside, Asiatic acid, and madecassic acid have a
bioavailability between 30 and 50%.
-Distribution: Bosse et al. reported that peak plasma levels are reached
2-4 hours after oral ingestion, intramuscular injection, or topical application
of Madecassol, a gotu kola preparation. Grimaldi et al. also found no
difference in time to peak plasma concentration with different dosages or
single versus chronic dosing in a crossover study of the total triterpenic
fraction of Centella asiatica (TTFCA). The area under the curve
significantly increased in a dose-dependent fashion after single doses of
either 30mg or 60mg TTFCA in humans.
After chronic treatment for seven days with either 30mg or
60mg TTFCA twice daily, it was observed that peak plasma concentrations, AUC0-24,
and half-life were significantly higher than after single dose administration,
possibly explained by the fact that asiaticoside is transformed into asiatic
acid in vivo.
-Metabolism: A study in 12 healthy
volunteers found that asiaticoside is converted to asiatic acid in vivo by hydrolytic cleavage of the sugar
moiety.
-Elimination: Madecassol is
predominantly eliminated in the feces within 24-76 hours after ingestion,
injection, or application, with a small unspecified amount metabolized by the
kidneys.
Edited and posted by Hồ Đình Hải
Edited and posted by Hồ Đình Hải
References
