Bacopa monniera

L. (Scrophulariaceae) (syn. Herpestis monniera (L.) Penn., Lysimachia monnieria L., Gratiola monnieria L. and Moniera cunefolia Michx)

English: Thyme-leaved gratiola
Hindi: Brahmi
Sanskrit: Barambhi, nirabarhmi

Brahmi forms the ingredient of a number of Ayurvedic prescriptions such as Brahmighritam, Brahmirasayanam, etc. and possesses numerous medicinal properties. Its use is documented in ancient Indian texts as far back as the 6th century and the herb has been widely used to promote the intellect and treat mental problems. It still occupies a predominant place in Hindu medicine and is used in Chinese medicine.

Habitat

The plant is commonly distributed in moist and damp areas on the edges of streams and water trenches. In India and other Asian countries it is found ascending to an altitude of 1320 m.

Botanical description

A small, prostrate, glabrous and fleshy herb (Plate 11). The leaves are sessile, soft, succulent, reniform, obovate-oblong or spatulate, up to 2.5 mm long, with obscure venation. The lower surface is punctate and entire. The stem is 10-30 cm long and 1-2 mm thick, with soft ascending branches. Flowers blue or white with purple veins, axillary and solitary on peduncles usually longer than the leaves, with linear bracteoles. Fruits ovoid, acute capsules included in the persistent calyx.

Parts used

Dried whole plant, mainly leaves and stems.

Traditional and modern use

The herb is used as an astringent, bitter and coolant. It is mainly used to promote the intellect and as a potent nervine, cardiotonic and diuretic, but is also said to have a positive effect in asthma, hoarseness and various types of insanity. It is included in many Ayurvedic formulations. It is recommended for children suffering from bronchitis and diarrhoea and the fresh juice of the plant is applied to inflamed joints to relieve pain.

Ethnoveterinary usage

Leaves and whole plants are used in tribal veterinary medicine, particularly in the treatment of epilepsy.

Major chemical constituents
Saponins and triterpenes

Dammaranes such as the bacosides and bacosaponins, based on the bacogenins A1-A5' are the most important constituents. These include bacosides A, Band C, with bacoside A constituting about 2.5-3%. Bacoside A produces ebelin lactone on acid hydrolysis and yields jujubogenin on degradation. Bacopasaponin D (a pseudojujubogenin glycoside), the bacopasaponins E and F (based on jujubogenin), hersaponin and monnierin have also been reported, together with the triterpenes betulic acid, bacosine, sitosterol, stigmastanol and stigmasterol.

Alkaloids

Brahmine and herpestine are present in the aerial parts.

Flavonoids

Flavonoids such as glucuronyl-7 -apigenin and glucuronyl-7 -luteolin are present along with luteolin-7 -glucoside and luteolin.

Medicinal and pharmacological activities

Effect on cognitive function: Cognitive effects of Bacopa monniera extract were evaluated in healthy human subjects in a double-blind, placebo-controlled, independent group trial design. The randomly allocated subjects received either placebo or brahmi (300 mg). B. monniera significantly improved the speed of visual information processing, learning rate and memory consolidation and anxiety compared to placebo, with maximal effects evident after 12 weeks, suggesting the role of brahmi in improving higher-order cognitive processes.2o It also produced a positive effect on passive-avoidance tasks, maximal electroshock seizures and locomotor activity in rats, by improving the cognitive effect. When administered along with phenytoin (PHT) for 2 weeks it significantly reversed PHT-induced impairment. Both acquisition and retention of memory showed improvement without affecting anticonvulsant activity." The extract may provide a useful contribution to the restoration of cognitive function, possibly in conjunction with the judicious application of growth factors.

Effect on learning: The effects on learning performance in rats were studied in different conditioning schedules by administering an aqueous suspension of an alcoholic extract (40 mg/kg, PO) for 3 or more days. The first schedule induced labile behaviour, using a shock-motivated brightness discrimination reaction. The treated group showed better acquisition, improved retention and delayed extinction. Similarly, in an active conditioned flight reaction, the drug-treated animals showed a shorter reaction time than the controls, which was confirmed in the continuous avoidance response. Treatment with brahmi also produced an improvement in learning capability confirmed by a maze-learning experimental method."

Anxiolytic activity: A standardised extract of B. monniera given to experimental models elicited a similar reaction to that of the benzodiazepine lorazepam and was dose dependent.

Antioxidant properties: Bacopa monniera exerted antioxidant activity on rat brain frontal cortical, striatal and hippocampal regions by altering superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) levels. The antioxidant activity was comparable to deprenyl. Bacopa monniera induced a dose-related activity in all brain regions, although deprenyl acted only on the frontal cortex and striatum. The effect was considered to be a result of the increase in oxidative free radical scavenging activity of the plant extract. The alcoholic extract of the herb has protective action against ferrous sulphate and cumene hydroperoxide-induced experimental lipid peroxidation, equivalent to the antioxidants tris, EDTA and vitamin E. The effect extended to hepatic glutathione content and was found to be dose dependent.

Spasmolytic activity: In animal studies, an ethanol extract of brahmi antagonised calcium channel activity. Spontaneous movement of smooth muscle induced by acetylcholine and histamine was inhibited by the plant extract, indicating a direct action. The effect of calcium chloride on blood vessels and jejunum was attenuated by the extract, implying a direct interference with influx of calcium ions. There was a lack of effect on either noradrenaline- or caffeine-induced contractions.

Bronchodilatory activity: An ethanol extract dilated the bronchial smooth muscles of anaesthetised rats, counteracting bronchoconstriction induced by carbachol.This property reduced expiratory pressure, resembling salbutamol rather than isoprenaline in manner. The action may be mediation through both adrenoceptor-dependent and independent mechanisms.

Analgesic activity: Bacosine was found to have analgesic activity but without barbiturate-type narcosis.

Safety profile

The plant is safe in usual therapeutic doses and adverse reactions are rare.

Dosage

Infusion: 8-16 ml Powder: 5-10 g

Ayurvedic properties

Rasa: Tikta (bitter)
Guna: Laghu (light), snigdha (unctuous) Veerya: Ushna (hot)
Vipaka: Katu (pungent)
Dosha: Pacifies kapha and vata