25 January, 2009

Etnobotany values of pegaga at varying locations throughout the world







Madagascar

A crystallized substance, asiaticoside, was found, thought at first to be a glucoside.
It has been shown that it is an ester. The compound broke down the leprosy nodules, perforating ulcers and lesions on fingers and early eye lesions. It has been suggested that this medicine probably dissolve at the waxy covering of the leprosy basillus so that it becomes fragile and can be easily destroyed either by the body.

India

The plant is valued in indigenous medicine for treatment of leprosy and skin diseases and also to improve memory.

A cold poultice of the fresh herb is used as an external application in rheumatism, elephantiasis and hydrocele.

For treating leprosy and other skin diseases it is given as an ointment or dusting powder.

Internally it has been valued as a tonic and is used in bronchitis, asthma, gastric catarahh, leucorrhoea, kidney troubles, urethritis and dropsy.

A decoction of very young shoots is given for haemorrhoids. It is used for Blood Conditions, Brain and Nervous System Conditions, Cardiovascular Conditions Gastrointestinal Conditions, Glandular Conditions, Immune System Conditions, cough problems, Liver Conditions, Respiratory Tract Conditions, and Tissue Development.


Medicinal and pharmacological activities

Antiulcerogenic activity: The antiulcerogenic activity of the fresh juice of C. asiatica wasstudied against ethanol-, aspirin-, cold restraint stress- and pyloric ligation-induced gastric ulcers in rats.

When given orally at doses of 200 and 600 mg/kg twice daily for 5 days, the drug showed significant protection against all the above experimental ulcer models. This effect was thought to be due to the strengthening of mucosal defensive factors.

Oral administration of Centella extract (0.05, 0.25 and 0.50 g/kg) before ethanol administration significantly inhibited gastric lesion formation (by 58-82%) and decreased mucosal myeloperoxidase (MPO) activity in a dose-dependent manner. It prevented gastric mucosal lesions by strengthening the mucosal barrier and reducing the damaging effects of free radicals.

Spasmolytic activity: Activity was demonstrated when tested in vitro on isolated guinea pig ileum.

Wound-healing activity: A titrated extract of Centella asiatica (TECA), containing asiatic acid, madecassic acid and asiaticoside, and its separate components were evaluated for their effects in the wound chamber model. TECA-injected wound chambers were characterised by increased dry weight, DNA, total protein, collagen and uronic acid contents.

Peptidic hydroxyproline was also increased, showing an increased remodelling of the collagen matrix in the wound. The three purified components ofTECA were all able to reproduce the effects of the complete drug. The activity of asiaticoside was studied in normal and delayed-type wound healing.

In guinea pig punch wounds topical applications of a 0.2% solution of asiaticoside produced a 56% increase in hydroxyproline, 57% increase in tensile strength, increased collagen content and improved epithelialisation.

In streptozotocin-diabetic rats, where healing is delayed, topical application of a 0.4% solution of asiaticoside over punch wounds increased hydroxyproline content, tensile strength, collagen content and epithelialisation, thereby facilitating healing.

Asiaticoside was also active by the oral route at 1 mg/kg and is thought to be the main active constituent of Centella asiatica. Asiaticoside enhanced antioxidant levels at an initial stage of wound healing which may be an important contributory factor in the healing properties of this constituent.

The extract also protected skin against radiation injury. Immunomodulatory activity: An alcoholic extract showed stimulatory effect on the reticuloendothelial system (RES) in mice and an in vitro study of the aq ueous extract demonstrated a positive effect on both the classic and alternative pathways of complement activation.

Antitubercular activity: An injection of 0.5 ml of a 4% solution of hydroxyasiaticoside was given in guinea pigs, inoculated 15 days preyiously with tubercle bacillus. It reduced the number of tubercular lesions in the liver, lungs, nerve ganglions and spleen and decreased the volume of the spleen over that of untreated control animals, thereby displaying antitubercular activity.

Psychoneurological activity: The alcoholic extract, when given orally to rats and mice treated with phenobarbitone, significantly prolonged sleeping time. In the maximum electroshock-induced convulsion test in rats, it significantly reduced the duration of individual convulsions. In a behavioural test it reduced the duration of the immobilityphase, indicating sedative, antidepressive and analgesic actions.

Antimicrobial activity: Asiaticoside at a concentration of 10 mglml showed antibacterial activity against Pseudomonas pyocyaneus and Trichoderma mentagrophytes.

Antiviral activity: The alcoholic extract showed antiviral activity against Herpes simplex type II virus.Antilarval activity: A new triterpenoid glycoside 3-0-[ a- L-arabinopyranosyl] 2a,3 p, 6p ,23a - tetrahydroxyurs-12-ene- 28-oic acid exhibited dose-dependent growth inhibitory activity against larvae of Spilarctia obliqua.



According to Hartwell (1967–1971), the flowers, leaves, and roots are used in folk remedies for tumors, the seed for abdominal tumors.

The root decoction is used in Nicaragua for dropsy. Root juice is applied externally as rubefacient or counter-irritant.

Leaves applied as poultice to sores, rubbed on the temples for headaches, and said to have purgative properties.

Bark, leaves and roots are acrid and pungent, and are taken to promote digestion. Oil is somewhat dangerous if taken internally, but is applied externally for skin diseases. Bark regarded as antiscorbic, and exudes a reddish gum with properties of tragacanth; sometimes used for diarrhea.

Roots are bitter, act as a tonic to the body and lungs, and are emmenagogue, expectorant, mild diuretic and stimulant in paralytic afflictions, epilepsy and hysteria.

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