2. ACTIVIDAD DEL SNS
2.3.4 O TRAS A CTIVIDADES
There are two kinds of veins that help return blood to the heart—
the superficial veins, which constitute 10 percent, and deep-seated veins, which constitute 90 percent. The superficial veins have valves that if not working can lead to stagnation of blood, pain in the legs, twisted contorted veins, and edema. Inadequate return of blood is termed venous insufficiency, which can lead to varicosity of veins or varicose veins. This can stem from lack of movement either because of the sedentary nature of work involving sitting at the desk or from professions involving long hours of standing.1
Centella asiatica (Linn.) Urban. (Family: Apiaceae)
Latin:Hydrocotyle asiatica Linn. Tamil: Vallarai Sanskrit: Mandukaparni
Hindi: Brahma Manduki
English: Indian Pennywort
Centella asiatica (see Plate 8 in color gallery) is a slender, creep-ing herb found in moist areas. The plant and the leaves are used medicinally for a variety of conditions. However, Centella asiatica is
best known in India as a mental rejuvenator (medhya rasayana) or memory tonic for reducing mental fatigue and improving mental clarity. For details see Chapter 12, “Central nervous system agents.”
It has also been used extensively for improving skin conditions of varied etiology and for healing of wounds and ulcers, both internally and externally. See Chapter 9 for its effect on wound healing. It is tra-ditionally used for improving blood circulation and reduction of edema stemming from debility.2,3
The major chemical constituents are the triterpenoid saponins—
madecassoside and asiaticoside— and their aglycones—asiatic acid and madecassic acid. Several other saponins including brahmoside and brahminoside, triterpenoid acids, and an alkaloid hydrocotyline have been isolated.4
Scientific studies based on clinical and pharmacological data have shown that it is useful in venous hypertension, venous insufficiency, and in varicose veins since it is useful in lowering levels of lysosomal enzymes that are considered responsible for valvular damage.5The triterpene glycoside, asiaticoside, has been shown to hasten wound healing by increasing collagen I synthesis.6Most of the trials have been conducted with the total triterpene fraction (TTFCA) or the ti-trated extract of Centella asiatica (TECA) containing 30 percent asi-atic acid, 30 percent madecassic acid, and 40 percent asiasi-aticoside;
however, a lipid preparation with Centella asiatica as major compo-nent has been recommended for capillary fragility.7
Extracts of Centella asiatica showed a positive effect on mucopolysaccharide metabolism when tried on patients with vari-cose veins. Basal levels of uronic acids and lysosomal enzymes are elevated in varicose vein patients, which indicate an increased mucopolysaccharide turnover in these patients. Treatment with 60 mg⭈day⫺1for 3 months of the active triterpenic fraction led to low-ering of elevated values of uronic acid and lysosomal enzymes result-ing in improved vein tonicity, vein dispensability, and decrease in subjective complaints in 80 percent patients with venous insuffi-ciency of the lower limbs.8
In a single-blind placebo-controlled trial, 89 patients with venous hypertension microangiopathy were treated with Centella asiatica extract. It was found that there was significant difference from the placebo
of all the parameters tested,9so that it was possible to distinguish between 60 and 120 mg daily.10Several models have been used to test the effect of Centella asiatica extract at two different dosage levels against placebo in venous hypertension and are reported in the October 2001 issue of Angiology.11Symptoms of venous hypertension such as ankle edema, pain and cramps, tiredness, and restless lower extremi-ties improved in the treated groups on 30 and 60 mg of Centella asiatica extract (TTFCA) thrice a day.12
In another study, 10 normal subjects, 22 with moderate superficial venous hypertension, and 12 with postphlebitic limbs and severe hy-pertension were studied first for 2 weeks without treatment and then after administering 60 mg Centella asiatica extract three times a day for 2 weeks. There was also improvement in capillary permeability in patients both with moderate superficial venous hypertension and se-vere venous hypertension having ankle and foot edema in the eve-ning.13
In a double-blind placebo-controlled trial, 94 patients with chronic venous insufficiency were administered either 60 or 120 mg per day of Centella asiatica extract (TECA) for 8 weeks. There was improvement in the feeling of heaviness in the limbs, edema, and in vein dis-pensability in the treated group, although vein disdis-pensability increased in the placebo group.14
The trials have been conducted using special extract or combina-tions of isolated components. It would be useful to study the effect of standardized plant material or simpler whole extracts to extend the scope of usage.
Centella asiatica is generally considered safe and has a low degree of toxicity. It is traditionally considered a vegetable and consumed as food.
No adverse reactions have been reported in doses commonly used. No mortality has been reported in mice up to 5 g⭈kg⫺1body weight.15
NOTES
1. Schlenger R. Volkskrankheit Venenleiden. Funktion und Erkrankungen des Venensystems. Deutsche Apoth Ztg 133:3202-3206 (1993).
2. Nadkarni AK. Dr KM Nadkarni’s Indian materia medica (vol. I, pp. 662-666).
Bombay: Popular Prakashan, 1976.
3. Gogte VM. Ayurvedic pharmacology and therapeutic uses of medicinal plants (pp. 466-468). Trans. SPARC, Mumbai: Bharatiya Vidya Bhavan, 2000.
4. Indian herbal pharmacopoeia (rev. new edn., pp.123-133). Mumbai: Indian Drug Manufacturers’ Association, 2002.
5. Tyler VE. Herbs of choice: The therapeutic use of phytomedicinals (pp. 111-112).
New York Pharmaceutical Products Press, 1994.
6. Bonte M, Dumas M, Chaudagne C, Meybeck A. Influence of asiatic acid, madecassic acid and asiaticoside on human collagen I synthesis. Planta Medica 60:133-135 (1994).
7. Anon. The therapeutic index. Addendum (p. 19). Madras: The Indian Medi-cal Practioners’ Co-operative Pharmacy and Stores (no year given).
8. Arpaia MR, Ferrone R, Amritano M, Nappo C, Leonardo G, del Guercio R.
Effect of Centella asiatica extract on mucopolysaccharide metabolism in subjects with varicose veins. Int J Clin Pharmacol Res 10:229-233 (1990).
9. Belcaro, et al. Efficacy of Centellase in the treatment of venous hypertension evaluated by a combined microcirculatory model. Curr Ther Res 46:1015 (1989)
10. Incandela L, Belacaro G, De Sanctis MT, Cesarone MR, Griffin M, Ippolito E, Bucci M, Cacchio M. Total triterpenic fraction of Centella asiatica in the treatment of venous hypertension: A clinical prospective, randomized trial using a combined microcirculatory model. Angiology 52 (suppl. 2):S61-67 (2001).
11. Angiology 52 (suppl.) (2001).
12. Belcaro GV, Rulo A, Grimaldi R. Capillary infiltration and ankle edema in patients with venous hypertension treated with TTFCA. Angiology 41:12-18 (1990).
13. Belcaro GV, Grimaldi R, Guidi G. Improvement of capillary permeablility in patients with venous hypertension after treatment with TTFCA. Angiology 41:533-540 (1990).
14. Pointel JP, Boccalon H, Cloarec M, Ledevehat C, Joubert M. Titrated extract of Centella asiatica (TECA) in the treatment of venous insufficiency of the lower limbs. Angiology 38:46-50 (1987).
15. Selected medicinal plants of India. A monograph on identity, safety and clini-cal usage (pp. 83-86). Bombay: Chemexcil Basic Chemiclini-cals, Pharmaceuticlini-cals and Cosmetics Export Promotion Council, 1992.