Bacopa monnieri (PROSEA)

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Plant Resources of South-East Asia
Introduction
List of species


Bacopa monnieri (L.) Pennell


Protologue: Proc. Acad. Nat. Sci. Philad. 98: 94 (1946).
Family: Scrophulariaceae
Chromosome number: 2n= 64

Synonyms

Lysimachia monnieri L. (1756), Gratiola monnieri (L.) L. (1759), Herpestis monnieria (L.) Kunth (1818), Bacopa monnieria (L.) Wettst. (1891).

Vernacular names

  • Water hyssop (En)
  • Malaysia: beremi
  • Philippines: ulasimang-aso (Tagalog)
  • Cambodia: (smau) sna:ô
  • Laos: ph’ôm mi’
  • Thailand: phak mi, phrommi (central)
  • Vietnam: rau (sam) dắng, ruột gà.

Origin and geographic distribution

B. monnieri probably originates from tropical Asia, and is now widespread throughout the tropics and subtropics.

Uses

In Peninsular Malaysia, a decoction of the leaves is taken to expel thread worms and also as an alterative. In the Philippines, a decoction of the whole plant is taken as a diuretic. In Indo-China, the whole plant is considered stimulant, diuretic and antispasmodic, and is administered as a kidney tonic, and also to treat scurvy, beri-beri, hoarseness and rheumatism. In Vietnam, the whole plant is furthermore taken as an appetitive and stomachic and used to treat dysentery. In China, it is mainly used for problems with the intestines, such as diarrhoea and colic.


In India, B. monnieri called "Brahmi", has a reputation in Ayurvedic medicine as a brain tonic, and is said to improve the intellect and combat forgetfulness. It is considered astringent, bitter and cooling. The whole plant is used as a nerve tonic, and in combination with other plants or alone, used as a cure for epilepsy, hysteria and insanity, and also as a cardiac tonic. The powdered dry leaves have given satisfactory results in cases of weakness, nervous breakdown and similar conditions.

In Peninsular Malaysia and Vietnam, the plant is sometimes eaten as a vegetable despite its bitterness. It is also cultivated as an ornamental for borders of ponds and aquaria.

Production and international trade

B. monnieri is cultivated in India as a medicinal plant. The dried herb, with standardized 50% bacosides (mainly bacosides A and B), is found in several Indian herbal nutritional supplements, called "Smart Drugs", especially as a support for the brain, and helping with fatigue and forgetfulness. In 2000, prices for 60 capsules were between US$ 20-30. In South-East Asia, Chinese herbalists stock the dried plant in their pharmacies.

Properties

The aerial parts contain the alkaloid herpestine, and the saponins monnierin (a tetrasaccharide of the sapogenin bacogenin A), hersaponin, and bacosides A, A3, B and C, as well as pseudojujubogenin glycosides C and D. Jujubogenin was obtained following hydrolysis of bacoside A. Other constituents are the triterpene bacosine, D-mannitol, betulinic acid, heptacosane, octacosane, nonacosane, triacontane, hentriacontane, dotriacontane, nicotine, 3-formyl-4-hydroxy-α-pyran, luteolin and its 7-glucoside.

In a toxicity test, the LD50of the plant extract was found to be more than 3000 mg/kg orally administered (p.o.) in mice and rats, and no sub-acute toxicity was found either in rodents or non-human primates. Bacoside A and B, which are the active components, were found to be non-toxic to chromosomes.

B. monnieri has been used since ancient times in India as a nerve tonic for improvement of memory. The administration of an alcoholic extract (40 mg/kg, p.o.) for three or more days improved the performance of rats in various learning situations, viz. a foot-shock motivated brightness discrimination response, active conditioned avoidance response and Sidman continuous avoidance response. Bacosides A and B are considered to be responsible for the facilitatory effect on learning schedules.


The anxiolytic (anxiety suppressing) activity of a standardized extract (bacoside A content about 25%) at doses of 5, 10 and 20 mg/kg p.o. was studied in rats, using the open-field, elevated plus-maze, social interaction, novelty-suppressed feeding latency and rotarod tests. The extract produced a dose-related anxiolytic activity, qualitatively comparable to that of benzodiazepine anxiolytic lorazepam, in all the test parameters, at doses of 10 and 20 mg/kg p.o. In addition, the advantage of the extract over lorazepam lies in the fact that it promotes cognition, unlike the amnesic action of the latter.

The effects of alcohol and hexane extracts as an antioxidant on FeSO4- and cumene hydroperoxide-induced lipid peroxidation and hepatic glutathione content were studied in rat liver homogenates. The alcohol extract showed greater protection against lipid peroxidation with both inducers. The extract only slightly protected the auto-oxidation and FeSO4-induced oxidation of reduced glutathione at doses of 100μg/ml and below, but at higher concentrations it enhanced the rate of oxidation.

In a further study, the effect of the standardized extract in doses of 5 and 10 mg/kg p.o., was assessed on rat brain frontal cortical, striatal and hippocampal superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) activities, following administration for 7, 14 or 21 days. A dose-related increase in these enzyme activities were observed after 14 and 21 days in all the brain regions investigated. The results were compared with the effects induced by the monoamine oxidase-B inhibitor selegiline (= (-)deprenyl) at 2 mg/kg p.o., administered for the same time periods, and it was found that selegiline induced an increase in SOD, CAT and GPX activities in the frontal cortex and striatum, but not in the hippocampus.

The saponin hersaponin is found to possess cardiotonic, sedative and spasmodic properties. It produced a mild inhibitory effect on the respiration of rat brain tissue which was partially reduced by LSD-25 and potentiated by 5-hydroxytryptamine (5-HT). The compound was also found, as in the case of reserpine, to deplete the noradrenalin and 5-HT content of the rat brain. An alcoholic extract of the plant, at a dose of 50 mg/kg, produced a tranquillizing effect on dogs and albino rats but the action was weaker than that produced by chlorpromazine.

In another test, different concentrations of the ethanolic extract were tested with Sarcoma-180 cell culture. The cell growth, viability and3H-thymidine incorporation into the DNA were assessed. Sarcoma-180 cell growth was significantly inhibited with increasing concentrations of the extract. The3H-thymidine uptake study suggested that the site of action of the drug may be at the DNA replication stage, when acting as an anticancer drug. The aqueous and alcoholic extracts were furthermore found to reduce the severity of seizures induced by drugs and electro-shock in rats, indicating that the extracts may have potential value in treating epilepsy.

Bacosine also exhibited moderate analgesic effects in mice and rats but was found to have no effect on barbiturate narcosis, haloperidol-induced catalepsy, spontaneous motor activity or conditioned avoidance response. The analgesic activity was furthermore found to be an opioid-like effect.


The bronchodilatory effect of the ethanol extract from plants collected in Pakistan, where they are used traditionally in the treatment of asthma, was examined using ring segments of pulmonary arteries (guinea-pig and rabbit), aorta (rabbit) and tracheal preparations (guinea-pig). The extract relaxed all tissues in a dose-dependent way. Pretreatment of the blood vessels with either atropine or propranolol did not alter the relaxant effect of the extract, while indomethacin reduced the extract-induced relaxation of all tissues. The effect of the extract on anaesthetized rats was reflected by a reduction in expiratory pressure which resembled a salbutamol-induced effect rather than that of isoprenaline. The action of the extract is probably mediated jointly byβ-adrenoceptor-dependent and independent mechanisms. The extract antagonized the bronchoconstrictor action of carbachol. The mechanism of this action was later found to be the inhibition of calcium influx via both voltage and receptor operated calcium channels of the cell membrane.

Description

A much branched, creeping herb, branches 5-40 cm long, somewhat fleshy, glabrous, rooting at the nodes. Leaves opposite, elliptical-ovate to spathulate, 6-15 mm × 4-9 mm, base tapering, apex obtuse, margins entire or obtusely serrate, midvein visible; petiole absent; stipules absent. Flowers axillary, solitary, slightly irregular, 5-merous, pedicel as long as or longer than the leaves; bracteoles 2, linear, calyx 4-5-parted, outer lobe broadly ovate, 5-6 mm long, the others lanceolate, apex acuminate; corolla tube cylindrical, 5-9 mm long, purplish at stamen insertion point, obscurely 2-lipped, upper lip 2-lobed, lower lip 3-lobed, 8-10 mm long, white to pale blue; stamens 4, in 2 pairs, inserted on the corolla tube, included, anthers 2-celled; style filiform, included, persistent. Fruit an ovoid capsule, as long as calyx, valves 2-4, seeds numerous. Seed ovoid, 0.5-0.8 mm long, ribbed, pale brown. Seedling with epigeal germination; cotyledons small, elliptical, glabrous; first leaves 2, ovate, midvein present, glabrous.

Growth and development

B. monnieri can be found flowering and fruiting throughout the year. The seeds are hydrochorous.

Other botanical information

Bacopa consists of about 55 species from tropical and warm regions, and 3-4 are present in South-East Asia. B. monniera is an orthographic variant of B. monnieria (L.) Wettst.

There seems to be considerable confusion in the United States and Australia about whether the Ayurvedic medicine "Brahmi" contains B. monnieri or Centella asiatica (L.) Urb. (synonym Hydrocotyle asiatica L. ( Umbelliferae )), although the last species is known in India as "gotu-kola". In fact, both species have partly similar medicinal uses, and contain compounds which exhibit e.g. central nervous system-depressant activity, and are useful for learning and in memory disorders. The two species do not resemble each other botanically and identification should therefore not be a problem.

Ecology

B. monnieri occurs in open wet localities, also rice fields, forming dense mats, mainly within the influence of salt and brackish water, on sandy soils along rivers, or on alkaline soils, from sea-level up to 300 m altitude.

Propagation and planting

B. monnieri is propagated by seed and by rooted cuttings. Minimum temperature for germination is 16C, maximum 28C, while the optimum is at 20C.


Reliable protocols for shoot regeneration and somatic embryogenesis have been developed. Node, internode and leaf explants were excised from shoots raised from axillary buds of nodal explants cultured on Murashige and Skoog (MS) basal medium. Leaf explants gave the largest number of shoot buds. Benzyladenine (BA) at 1.5-2 mg/l was best for inducing the highest number of shoot buds. MS + 0.1 mg BA + 0.2 mg indole acetic acid/l was the most suitable for shoot elongation. Elongated shoots were rooted on MS medium with or without 0.5-1 mg indole butyric acid or 0.5-1 mg naphthalene acetic acid/l. Rooted plants were successfully established in soil. Calluses derived from nodal explants cultured on MS medium containing 0.5 mg 2,4-D/l developed somatic embryos, which germinated either on the same media or on MS basal medium. The resulting plantlets were successfully transplanted to soil.

Husbandry

B. monnieri needs to be planted in the full sun, on rather heavy soils with continuous water supply, in order to prevent the soil from drying out.

Diseases and pests

The caterpillars of the white peacock butterfly ( Anartia jatrophae ) have a preference for B. monnieri as a feed plant. Under greenhouse conditions, the grasshopper Spodoptera litura can do much damage. B. monnieri is a host for several nematodes ( Meloidogyne spp.).

Harvesting

When B. monnieri is harvested from the wild, great care should be taken to harvest it from unpolluted sites, as it can take up considerable amounts of heavy metals. Marked seasonal changes in chemical constituents, especially the saponins, have been observed.

Handling after harvest

The pretreatment of harvested shoots of B. monnieri to 80C in an oven for 30 minutes before drying at 37C helps to retain higher amounts of bacoside A in the dried plant material.

Genetic resources and breeding

B. monnieri is widespread and common throughout South-East Asia, and therefore does not seem to be at risk of genetic erosion. In India, B. monnieri has been entered in a programme for micropropagation, breeding and germplasm conservation.

Prospects

Extracts and purified compounds from B. monnieri show a range of interesting pharmacological activities both in vitro and in vivo animal models. Especially the positive results of B. monnieri preparations with learning schedules in rats, enhancing mental retention capacity and memory, and the effects as an anxiolytic look promising. Therefore, appropriate clinical evidence should be acquired with humans, in order to evaluate their future potential.


Literature

  • Bhattacharya, S.K., Bhattacharya, A., Kumar, A. & Ghosal, S., 2000. Antioxidant activity of Bacopa monniera in rat frontal cortex, striatum and hippocampus. Phytotherapy Research 14(3): 174-179.
  • Dar, A. & Channa, S., 1997. Bronchodilatory and cardiovascular effects of an ethanol extract of Bacopa monniera in anaesthetized rats. Phytomedicine 4(4): 319-323.
  • Elangovan, V., Govindasamy, S., Ramamoorthy, N. & Balakrishna, K., 1995. In vitro studies on the anticancer activity of Bacopa monnieri. Fitoterapia 66(3): 211-215.
  • Perry, L.M., 1980. Medicinal plants of East and Southeast Asia. Attributed properties and uses. MIT Press, Cambridge, Massachusetts, United States & London, United Kingdom. p. 382.
  • Philcox, D., 1979. Clarification of the name Bacopa monnieri (Scrophulariaceae). Kew Bulletin 33(4): 679-680.
  • Vohora, S.B., Khanna, T., Athar, M. & Ahmad, B., 1997. Analgesic activity of bacosine, a new triterpene isolated from Bacopa monnieri. Fitoterapia 68(4): 361-365.

Other selected sources

74, 112,

  • Burkill, I.H., 1966. A dictionary of the economic products of the Malay Peninsula. Revised reprint. 2 volumes. Ministry of Agriculture and Co-operatives, Kuala Lumpur, Malaysia. Vol. 1 (A-H) pp. 1-1240, Vol. 2 (I-Z) pp. 1241-2444.

215, 229, 311, 377, 739, 810, 921, 940, 1005, 1012.

Authors

N.O. Aguilar