Gotu Kola

Scientific Name(s): Centella asiatica (L.) Urban. Family: Apiaceae (carrots)

Common Name(s): Gotu kola (Chinese), Indian Pennywort (English), Brahmi (Hindi), Manduukaparani (Ayurveda), Tsubokusa (Japan), hydrocotyle , talepetrako , spadeleaf , Asiatic pennywort

Uses

Gotu kola has been traditionally used as treatment for a variety of conditions and as an aphrodisiac. There is potential efficacy in treating wounds, varicose veins, skin disorders, venous insufficiency, and to enhance memory, although there is little clinical information to support these claims.

Dosing

Dosages of gotu kola in crude form range from 1.5 to 4 g/day. Various extracts standardized to asiaticoside content also are available and have been studied in clinical trials in venous insufficiency and wound healing at doses of 30 to 90 mg/day. Wound-healing studies have involved topical application of a hydrogel ointment containing a titrated extract of C. asiatica (TECA). Commercial manufacturers have numerous dosage regimens listed for gotu kola.

Contraindications

Avoid use if hypersensitive to any of the ingredients of C. asiatica or gotu kola.

Pregnancy/Lactation

Avoid use during pregnancy and lactation, because gotu kola may have emmenagogue effects.

Interactions

None well documented.

Adverse Reactions

Contact dermatitis is documented in some clinical trials.

Toxicology

Three cases of hepatotoxicity have been reported with patients using C. asiatica for 20 to 60 days.

Botany

C. asiatica is a perennial herbaceous creeping plant in the genus Centella (Apiceae). , The plant is also known as gotu kola and grows abundantly in shady, moist, or marshy areas. It is distributed widely in many parts of the world, including India, Sri Lanka, Madagascar, South Africa, Australia, China, and Japan. , ,

History

Gotu kola has a long history of therapeutic uses in numerous medicinal systems dating back many centuries. In India, the plant has been used to treat dermatitis, diabetes, cough, cataracts and other eye conditions, and to improve memory. In Europe, an infusion of the aerial parts of the plant was used to purify the blood and treat wounds, ulcers, dermatitis, and hypertension. A similar infusion has been used in Indonesia and Brazil to help improve memory. In Malaysia, the plant was used to treat respiratory ailments, such as bronchitis and asthma, and gastric complaints, including dysentery, kidney trouble, urethritis, and dropsy (edema). In Malaya, an infusion from this plant is sold as a tonic and cold beverage to treat liver ailments, tuberculosis, and blood in the urine. In the past, people in Japan valued the plant for its diuretic and detoxicant properties. , , Sri Lankans noticed that elephants, known for their longevity, ate the leaves of the plant. Thus, the leaves were believed to promote long life, with a suggested "dosage" of a few leaves each day. In South China, the plant is used as a dietary supplement to promote health and immune system function.

The plant species is native to China, India, Sri Lanka, and Indonesia, and is being introduced to other countries.

Gotu kola should not be confused with the dried seed of Cola nitida (Vent.) Schott. and Endl. (also known as kolanuts, kola, or cola), the plant used in cola beverages. C. nitida contains caffeine and is a stimulant. Gotu kola has no caffeine and has sedative properties.

Chemistry

The triterpenoids are the major components responsible for the medicinal activity of the plant. , However, the plant species also contains more than 70 constituents, including polyacetylenes, flavonoids, flavones, sterols, and lipids. , , Below-ground parts of the plant contain small amounts of at least 14 different polyacetylenes. A phytochemical study revealed the presence of amino acids, flavonols, fatty acids, alkaloids, sterols, saccharides, and inorganic salts. A study of powdered gotu kola by microscopic and chemical identification methods has also been conducted. The active constituents of the plant are the same components found in many drugs and cosmetic preparations.

Many studies focus on the triterpenoids asiaticoside, centelloside, madecassoside, and asiatic acid. Asiaticoside has anxiolytic, anti-inflammatory, antioxidant, antiulcer, and wound-healing properties. Asiaticoside and madecassoside may be effective in treating arthritis. Asiatic acid induces apoptosis and cell cycle arrest in several types of cancer in rats.

The pharmacokinetics of the total triterpene fraction of gotu kola have been studied after single and multiple administration to healthy volunteers. Using a high-pressure liquid chromatography procedure for detection of asiatic acid, researchers found that after chronic treatment at 2 doses, the peak plasma concentration, area under the curve, and half-life were higher than those observed after the corresponding single-dose administration. Pharmacokinetic studies have also been completed in animals.

Uses and Pharmacology

Numerous animal and clinical studies investigate the plant's therapeutic potential in treating infections, and as an antidepressant, analgesic, sedative, and wound-healing agent.

Anxiety
Animal data

Traditionally, gotu kola has been used in Ayurvedic and Chinese medicine to relieve anxiety and promote relaxation. A study conducted in rats compared the impact of different phytochemicals in gotu kola with placebo. During one portion of the study protocol, rats were given a commercial product from Madagascar that contained high levels of triterpene or placebo (ie, distilled water). The gotu kola groups received either 200 or 500 mg/kg of each product. Anxiolytic effects were noted in multiple measures assessed in both groups receiving high doses of gotu kola products; however, anxiolytic effects were not noted in either group at the lower dose. No differences were noted between the 2 commercial products. In another portion of this study, a hexane extract, ethyl acetate extract, and methanol extract were compared. Improvements in measures of behavior were noted in rats receiving ethyl acetate and methanol extracts. Rats receiving the hexane extract did not appear to have any improvement in behavioral symptoms. These findings are consistent with the fact that the asiaticoside concentration is lowest in the hexane extract and highest in the methanol extract. In a third portion of this study, dose-dependent assessments using pure asiaticoside found changes in behavioral and anxiety measures compared with controls. However, no differences between rats receiving asiaticoside and those receiving placebo were noted in locomotor activity, suggesting that gotu kola does not cause sedation in rats. Additional rat behavioral model studies document the anxiolytic activity of asiaticoside.

Clinical data

To determine gotu kolas effects on anxiety in humans, 40 healthy volunteers were randomly assigned to receive a single oral dose of gotu kola 12 g (n = 20) or placebo (n = 20). The acoustic startle response was reduced 60 and 90 minutes after the administration of a single dose of gotu kola, which may suggest a potential anxiolytic effect. No effects were noted on self-rated mood, heart rate, or blood pressure.

Chemotherapy and radiation-induced toxicity

The cancer chemotherapeutic agents adriamycin and doxorubicin produce dose-dependent toxicity in the heart, limiting the total cumulative dose allowable. This effect is in part caused by oxidative damage to membrane lipids. Mitochondrial dysfunction is believed to also play a role in doxorubicin-associated cardiotoxicity. Thus, agents with potential antioxidant activity, such as C. asiatica , may protect against oxidative damage resulting from doxorubicin administration. C. asiatica antioxidant properties are believed to result from its phenolic compounds. The antioxidant activity of the plant may also be beneficial in reducing radiation-induced toxicity.

Animal data

A study was conducted in adult male albino rats. The rats were divided into the following 4 groups: group 1 received placebo; group 2 received doxorubicin 2.5 mg/kg in 6 equal injections over 2 weeks; group 3 received an extract of C. asiatica (200 mg/kg); and group 4 received both doxorubicin and the extract of C. asiatica . The extract was given 1 week prior to doxorubicin and for 2 weeks during doxorubicin administration. At the end of this study, cardiac enzyme markers were significantly lower in rats treated with doxorubicin compared with placebo ( P < 0.05). However, the rats in group 4, who received pretreatment and simultaneous administration of C. asiatica and doxorubicin, did not have a significant change in cardiac enzyme markers ( P < 0.05). The same was also true for mitochondrial enzymes and respiratory marker enzymes in the respective groups. Additionally, morphological changes, such as severe swelling of the mitochondria and nucleus, were noted in the rats in group 2. However, rats receiving doxorubicin in combination with C. asiatica appeared to have normal morphology and mitochondrial ultrastructure. C. asiatica was concluded to be potentially effective in reducing the dose-dependent effect of cardiotoxicity associated with doxorubicin therapy because of its antioxidant properties.

Taste aversion and weight loss can be undesired results of radiation therapy. Male rats were exposed to low-dose, whole-body gamma radiation and received an aqueous extract of C. asiatica 100 mg/kg or ondansetron 1 mg/kg. Rats treated with ondansetron had more protection against conditioned taste aversion on the first postirradiation day. However, both ondansetron and C. asiatica appeared equally effective on the second postirradiation day. Additionally, rats receiving C. asiatica continued to experience a decline in conditioned taste aversion up to 5 days postirradition. This pattern was unlike that in rats treated with ondansetron. The aqueous extract also inhibited radiation-induced weight loss. Thus, it was concluded that C. asiatica offers a potential option in the prevention of radiation-induced taste aversion and weight loss. , An in vitro and in vivo study documents that C. asiatica also protected DNA and membranes against gamma radiation in mice.

Hypertension
Clinical data

C. asiatica has been used to improve circulation in patients with venous hypertension and microangiopathy. The efficacy of centellase from C. asiatica in the treatment of venous hypertension has been evaluated using a combined microcirculatory model. The researchers conducted a single-blind, placebo-controlled, randomized study of the effects of the total triterpenoid fraction (centellase) in 89 patients with venous hypertension microangiopathy. The hypotensive effects of centellase differed from placebo in activity on all the microcirculatory parameters investigated. No adverse reactions were noted.

Another study was conducted in 62 patients divided into 4 groups: group 1 consisted of patients with venous hypertension (ie, ambulatory venous pressure more than 42 mm Hg) who received total triterpene fraction of C. asiatica (TTFCA) 60 mg 3 times daily; group 2 consisted of patients with venous hypertension who received TTFCA 30 mg 3 times daily; group 3 consisted of patients with venous hypertension who received placebo; and group 4 consisted of healthy patients who received TTFCA 60 mg 3 times daily. Patients received treatment for 4 weeks. Various measures of venous hypertension, including ankle edema, ankle circumference, and capillary filtration rate, improved in groups 1 and 2 after 4 weeks of therapy. No change was noted in the placebo group or in the healthy group.

In a similar study, patients with venous hypertension (ambulatory venous pressure more than 42 mm Hg) were divided into 3 groups: group 1 received TTFCA 60 mg 3 times daily; group 2 received 30 mg 3 times daily; and group 3 received placebo. A fourth group of healthy patients served as a comparator group and received TTFCA 60 mg 3 times daily. Patients received treatment for a period of 4 weeks. Measures of venous hypertension (capillary filtration rate, ankle edema, and ankle circumference) were improved in patients receiving treatment with TTFCA, and the effects were greater in patients receiving higher-dose TTFCA (60 mg 3 times daily). Symptoms were also improved in subjects receiving TTFCA.

In a study involving 40 patients with severe venous hypertension, ankle swelling, and/or lipodermatosclerosis, patients were randomized to receive 8 weeks of treatment with either TTFCA 60 mg orally twice daily or placebo. At the end of this study, there was a decrease in flux at rest and rate of ankle swelling in patients receiving TTFCA compared with placebo ( P < 0.05). In addition, symptoms improved as a result of decreased capillary filtration in patients receiving TTFCA ( P < 0.05). The conclusion was that TTFCA was effective in improving venous microangiopathy.

Infection
In vitro data

An in vitro study in India was performed to determine the antibacterial effects of an extract of C. asiatica against enteric pathogens as an antidiarrheal product. Microorganisms studied included strains of Escherichia coli , Staphylococcus aureus , Pseudomonas aeruginosa , Vibrio cholerae , and Shigella . Antibacterial activity was noted with all concentrations of the extract (100, 200, 300, and 400 mg/mL); however, inhibitory effects were most prominent with the 400 mg/mL concentration. Bactericidal effects against the Shigella species, one of the V. cholerae species, and S. aureus were noted within 2 hours. Thus, this preliminary study suggests the potential effects of C. asiatica extract as an option for the treatment of diarrhea. An in vitro study using a disc diffusion method documented that C. asiatica also has activity against methicillin-resistant S. aureus .

A topical form of C. asiatica had repellant activity against malarial vector Anopheles stephensi in studies conducted in mosquito cages. This mosquito is responsible for nearly 50% of malarial cases in West Asian countries. , ,

Memory and Mood
In vitro and animal data

To assess the effects of C. asiatica on brain function and neuronal maturation following birth, an aqueous extract of C. asiatica was given orally to mice in weight-based doses during the postpartum period. Multiple behavioral tests were conducted, including the radial arm maze test involving the selection of food used to test spatial memory. Three-month-old mice receiving C. asiatica showed a dose-dependent increase in performance of the radial arm maze, demonstrating that C. asiatica can improve cognitive function in young mice. Higher doses were associated with more correct entries compared with lower doses. However, mice receiving lower doses completed the radial arm maze more rapidly than those receiving higher doses, which may be explained by the depressant effects seen with higher-dose C. asiatica .

A small study was conducted in 7-day-old Wistar rats to assess the effects of C. asiatica fresh leaf juice on learning and memory during the neonatal period. Rats were divided into treatment groups of 2-, 4-, and 6-week duration. From these groups, rats were further divided into treatment arms consisting of normal controls, saline controls, and rats receiving C. asiatica , which was further subdivided into doses of 2, 4, and 6 mL/kg. Overall, the learning measures of rats receiving the low dose of C. asiatica 2 mL/kg for 2 weeks did not differ from those of normal control rats. Additionally, rats receiving higher doses for the short duration improved their learning behaviors. Rats receiving all doses of C. asiatica for 4 or 6 weeks demonstrated improvement in learning behaviors. Memory retention also improved in rats receiving all 3 doses of the extract for all 3 time periods. It was concluded that administration of C. asiatica to neonatal rats can improve learning and memory.

An in vitro study documents a 50% inhibition of acetylcholinesterase activity at concentrations of 100 to 150 mcg/mL with C. asiatica . Acetylcholinesterase inhibitors are used to treat the cognitive decline in Alzheimer disease. In an animal model, a C. asiatica extract decreased amyloid beta plaque formation that is associated with the neurodegenerative changes in Alzheimer disease. The mechanism of action may be associated with the plant's antioxidant activity, as well as its effect on certain signaling pathways (ie, ERK/RSK signaling pathway). Several animal studies also document that treatment with C. asiatica increases dendritic length (intersections) and branches of neurons of amygdala, which enhances learning and memory , , , and may also provide an antianxiolytic effect.

The tail suspension test is a well-established screening model for antidepressants. Asiaticoside reduced the immobility time in a mouse model. The antidepressant-like effect may be related to regulation of alpha-2-adrenergic receptors. Another mechanism of action may involve altering the activity of the hypothalamic-pituitary-adrenal axis and increasing the levels of monoamine neurotransmitters.

Clinical data

In an 8-week randomized, placebo-controlled, double-blind pilot study of 28 patients, C. asiatica extract enhanced spatial and numeric working memory and attention, and improved mood. Patients were administered 250, 500, or 750 mg of C. asiatica in capsule form or placebo. The most important changes occurred in patients treated with 750 mg/day. The underlying mechanism may involve C. asiatica modulating dopamine and norepinephrine in the prefrontal cortex, and acetylcholine and serotonin in the hippocampus, leading to improved numeric and spatial memory.

Psoriasis
Clinical data

C. asiatica has shown promise in the treatment of psoriasis. When creams containing oil and water extracts of the leaves were administered each morning to 7 psoriatic patients, 5 patients displayed complete clearance of lesions within 3 to 7 weeks. One patient experienced clearance of most lesions, and one demonstrated improvement without clearance. Another patient demonstrated a mild recurrence 4 months after treatment. Although this study was not controlled, a placebo effect was considered unlikely. Experience indicated that the creams were nontoxic and cosmetically acceptable, making them suitable for long-term use.

A double-blind, randomized, placebo-controlled, clinical study of 25 patients documented that application of an herbal gel extract containing C. asiatica increased skin firmness and elasticity. The gel is used in China, India, and the Mediterranean area. These results were also supported by additional studies. ,

Other studies with various topical herbal extracts containing C. asiatica report beneficial skin effects in cold and dry weather conditions, with chronically sun-damaged skin, and in skin hydration.

Venous insufficiency
Clinical data

A double-blind, placebo-controlled study of 94 patients with venous insufficiency of the lower limbs indicated that TECA produced clinical improvement in this condition. The patients received 12 or 60 mg/day for 8 weeks. Improvement occurred in subjective measures of sensation of heaviness and pain in the legs, edema, overall patient assessment of efficacy, and in the objective measure of vein distensibility. The researchers concluded that TECA stimulated collagen synthesis in the vein wall, thus increasing tonicity and reducing its capacity to distend. In contrast, patients receiving placebo exhibited an increase in vein distensibility. Although there was no statistically significant difference between the 2 TECA dosage groups, data trends suggested that the effect of TECA was dose-related.

A study was conducted to assess the role of C. asiatica in the prevention of edema and changes in circulation measures for patients traveling on an airline flight of at least 3 hours. Patients between 30 and 50 years of age with mild to moderate venous insufficiency and varicose veins were randomized to receive TTFCA 60 mg 3 times daily beginning 2 days before the flight, the day of the flight, and 1 day following the flight, or to receive no treatment. Those receiving TTFCA had less edema, while those in the control group continued to experience an increase in edema and worsening of other measures of circulation. These findings were consistent in those patients on flights of up to 10 hours duration. It was concluded that TTFCA presents an option for patients who are prone to edema, particularly on long flights.

Wound healing

The wound-healing effect of the glycoside madecassoside may involve several mechanisms, including antioxidant activity and effects on collagen synthesis and angiogenesis. Asiaticoside appears to stimulate would healing by inducing type 1 collagen synthesis and promoting angiogenesis.

Animal data

Experiments with rats have established that wounds heal by a process involving dilation followed by contraction. However, TECA 100 mg/kg accelerated healing time. A study using rats and mice found that topically applied TECA rapidly penetrated to subcutaneous tissues and abdominal muscle in high concentrations and had a greater effect on wound healing than oral administration. Asiatic acid was absorbed later than madecassic acid. The topical preparations of TECA were also able to penetrate to the plasma and deeper tissues.

Topical application of asiaticoside 0.2% solution to guinea pig punch wounds resulted in a 57% increase in tensile strength, an increase in collagen content, and improved epithelialization. Oral doses of the asiaticoside 1 mg/kg solution also appeared to promote wound healing in guinea pigs.

In another study, the effects of C. asiatica were assessed in rats receiving dexamethasone, a glucocorticoid known to suppress wound healing. Wistar albino rats were divided into 4 groups: group 1 contained rats with wounds treated with normal saline; group 2 contained rats with wounds treated with an ethanolic extract of C. asiatica ; group 3 contained rats with wounds treated solely with dexamethasone; and group 4 contained wounded rats that received C. asiatica extract and dexamethasone. Three different wound models were studied, including dead space, incision, and excision wounds. The type of wound dictated the duration of therapy with C. asiatica (ie, daily for 10 days of therapy for dead space and incision wounds, and daily until the day of epithelization for rats with excision wounds). Rats treated with C. asiatica experienced an increase in wound-breaking strength, weight, and dry tissue weight, and hydroxyproline content, suggesting an increase in collagen content. Those treated with dexamethasone only (group 3) experienced a worsening of these parameters. However, rats in group 4 receiving dexamethasone and C. asiatica experienced an increase in these parameters. It was concluded that an ethanolic extract of C. asiatica promoted wound healing in rats because of the antioxidant properties of C. asiatica .

Because of the potential role in enhancing wound healing, the antioxidant effect of C. asiatica was studied in the wound-healing process in rats. A topical solution of asiaticoside 0.2% was applied twice daily for 7 days to cutaneous wounds in rats. The newly formed tissue had increased levels of antioxidants. However, antioxidant levels did not appear to differ from controls after 14 days of topical asiaticoside application.

Clinical data

C. asiatica extracts promote wound healing in humans. There are 4 phases of wound healing: an initial period of vasoconstriction and hemostasis, followed by an inflammatory phase, a proliferative phase, and remodeling. C. asiatica appears to be effective in the proliferative phase through promotion of the production of type 1 collagen. Other mechanisms by which C. asiatica may be beneficial in wound healing include a reduction in the inflammatory response and production of myofibroblasts.

Cell culture experiments have shown that the total triterpenoid fraction of the extracts at a concentration of 25 mcg/mL does not affect cell proliferation, total cell protein synthesis, or the biosynthesis of proteoglycans in human skin fibroblasts. However, the fraction does increase the collagen content of cell layer fibronectin, which may explain the action in wound healing.

TECA has been used as a scarring agent to stimulate wound healing in patients with chronic lesions, such as cutaneous ulcers, surgical wounds, fistulas, and gynecologic lesions. A clinical study evaluated TECA for treating bladder lesions in 102 patients with bilharzial infections. Injections of TECA 2%, usually administered intramuscularly for 1 to 3 months, produced cure or improvement in 75% of the cases, as determined from symptoms and urinary and cystoscopic findings. Healing occurred with little scar formation, avoiding much of the loss of bladder capacity that can result from bilharzial infections.

Though studies are lacking, the use of gotu kola in combination with other herbal products, such as horse chestnut, butcher's broom, witch hazel, or stone root, has been considered to improve the healing time of hemorrhoids due to gotu kola's ability to increase tensile strength and collagen content in the wound-healing process, as well as its ability to enhance microcirculation.

Other pharmacologic activity
Antifertility effects

Reduction of fertility in female mice was found with 2 compounds from the crude extract of gotu kola: isothankuniside and BK compound (methyl 5-hydroxy-3,6-dioxo-23 [or 24]-nor-urs-12-ene-28-oate). No appreciable effects were reported with the crude extract. Mice treated with isothankuniside in 1 and 2 mg doses resulted in 15% to 35% more sterile matings when administered for the first 3 days of each week for 21 days. BK compound administered over the same treatment period was even more effective. Because this was a preliminary screening study, the mechanism for this effect was not investigated.

Cancer

Centella extract may be effective in killing cultured cancer tumor cells. The extract, a 5:1 concentrate extracted with methanol, was effective at a level of 100 mcg/mL. In addition, no toxic effects were detected in normal human lymphocytes. A preliminary French study showed TECA produced histologic improvement in 5 of 12 patients with chronic hepatic disorders. The triterpene asiaticoside from C. asiatica may induce apoptosis and enhance the anticancer activity of vincristine in several cancer cell lines. Another in vitro study documented that asiatic acid isolated from C. asiatica -induced apoptosis and inhibited colon cancer cell growth by interfering with the mitochondrial membrane potential in a concentration and time-dependent manner.

Cholesterol

Rats fed C. asiatica powder had significantly ( P < 0.05) lower serum low-density lipoprotein and triglycerides and higher high-density lipoprotein when compared with controls. However, cholesterol levels of rats fed either C. asiatica extract or powder were higher compared with controls. An in vivo rabbit study documented that madecassoside protected against myocardial ischemia reperfusion injury, possibly through antioxidant, antilipid, anti-inflammation, and antiapoptosis activity.

Diabetes

In a small study involving fasted rabbits, C. asiatica 2 and 4 g/kg were administered to assess its effects on blood glucose. Extract administration resulted in a 26% mean deviation in blood glucose levels for rabbits receiving 2 g/kg and 35% mean deviation for those receiving 4 g/kg ( P < 0.05).

Diabetic microangiopathy

A study was conducted in 50 patients with diabetic microangiopathy to assess the effects of C. asiatica . Thirty patients received oral TTFCA 60 mg twice daily for 6 months, 10 patients received placebo, and 10 patients received no treatment. Measures of microcirculation improved in patients receiving C. asiatica after 6 months of treatment. No changes were noted in patients receiving placebo or in those receiving no treatment. It was concluded that TTFCA has a potential role in improving microcirculation in patients with diabetic microangiopathy.

Ethanol-induced gastric ulceration

An extract of C. asiatica was given orally to rats prior to ethanol administration in doses of 0.05, 0.25, or 0.5 g/kg. Premedication with C. asiatica resulted in a 58% to 82% dose-dependent reduction in the formation of gastric lesions. These results were believed to be the result of strengthening of the gastric mucosa and a reduction in free radicals.

Joint disease

Asiaticoside reduced articular cartilage degeneration and inflammatory cell infiltration in mice with collagen-induced arthritis. The underlying mechanism may involve inhibiting lymphocyte proliferation and reducing cyclooxygenase-2 and cytokine expression. , Madecassoside also provides a protective effect in joint destruction by potentially regulating abnormal humoral and cellular immunity. The results of an in vitro and in vivo study demonstrated that a standardized C. asiatica fraction inhibited zymosan-induced cartilage damage by potentially inhibiting nitric oxide production. Nitric oxide plays a role in cartilage degradation in osteoarthritis.

Varicose veins

The effect of gotu kola extract on mucopolysaccharide metabolism was studied in subjects with varicose veins. The total triterpene fraction of the plant (60 mg/day for 3 months) elevated the basal levels of uronic acids and lysosomal enzymes, indicating an increased mucopolysaccharide turnover in varicose vein patients. These results confirm the regulatory properties of C. asiatica extract on the metabolism in the connective tissue of the vascular wall.

Dosage

Dosages of gotu kola in crude form range from 1.5 to 4 g/day. Various extracts standardized to asiaticoside content are available and have been studied in clinical trials for potential treatment of venous insufficiency and wound healing at dosages of 30 to 90 mg/day. Wound-healing studies have involved topical application of a hydrogel ointment containing TECA. ,

Gotu kola is available in numerous dosage forms including capsules, creams, powders, liquids, and teas. Commercial manufacturers have numerous dosage regimens listed for gotu kola.

Pregnancy/Lactation

Avoid use during pregnancy and lactation, because gotu kola may have emmenagogue effects.

Interactions

Antiepileptics

Theoretically, gotu kola may interact with this drug class. The median effective dose of phenytoin, valproate, and gabapentin were found to be 13, 104, and 310 mg/kg body weight, respectively. However, during the presence of a C. asiatica ethyl acetate fraction the corresponding values were 5, 29, and 79 mg/kg body weight, respectively. In an in vitro experiment, 1 mg/mL extracts from C. asiatica stimulated glutamic acid decarboxylase activity by more than 40%.

Erectile dysfunction medications

An herbal product containing C. asiatica enhanced erectile function in rats. Some activities of the herbal product were comparable with sildenafil.

Famotidine

Antiulcer activity of C. asiatica in rats was comparable with famotidine and sodium valproate.

Sucralfate

A 600 mg/kg dose of C. asiatica given to rats twice daily for 5 days protected against induced gastric ulceration. The effects were comparable with sucralfate 250 mg/kg by mouth once a day for 5 days. C. asiatica increased gastric juice mucin secretion and mucosal cell glycoproteins, and decreased cell shedding, which leads to an increase in the mucosal barrier.

Adverse Reactions

Contact dermatitis ha