Vasaka has been used in Indian medicine for over 2000 years. The leaf buds are chewed, sometimes with ginger, by sadhus. This helps to clear the respiratory passages during their yogic breathing exercise.
The plant grows throughout the Indian peninsula up to an altitude of 1300 m, on wastelands in a variety of habitats and types of soil. It is sometimes cultivated as a hedge plant and the twigs and leaves used as 'green manure'. It is also found in Sri Lanka and Malaysia.
Vasaka is a small, evergreen, perennial shrub, reaching 1-2.5 m high with opposite, ascending branches (Plate 4). The leaves are simple, opposite, Ian ceo late and leathery, 7-19 cm long and 4-7 cm wide, pubescent, . and light green in colour above, darker on the lower surface. The flowers are large, dense, terminal spikes with large bracts. The corolla is white, the lower lip often streaked with pink or purple, and the capsule small, clavate and longitudinally channelled, containing four globular seeds.
Leaves, roots, flowers and bark.
Adhatoda vasica has been most commonly used for the treatment of respiratory complaints and diseases such as coughs, colds and asthma.' The leaves are boiled and taken orally for fevers and warmed leaves are applied externally for rheumatic pains and dislocation of joints. The powder, boiled in sesame oil, is used as a local application for ear infection and to stop bleeding. In Nepal, a dried water extract of leaves is used to relieve stomach acidity and in Bihar and other parts of India, a decoction of the leaves is used to facilitate childbirth or induce abortion. A paste of the leaves is sometimes applied to the abdomen to treat urinary disorders.2,3The leaves and flowers are cooked as a vegetable by the Khasi tribe in India: It has been used by European herbal practitioners as an antispasmodic, expectorant and febrifuge.
The leaves and rhizome are used in coughs and colds in ruminants and generally in treating diseases such as abscesses, anthrax, throat diseases, asthma, tuberculosis, jaundice, scabies, urticaria, rheumatism, pneumonia, haematuria and contagious abortions.
Vasicine (= peganine), a quinazoline alkaloid, is the major alkaloid present in all parts of the plant. The leaves also contain vasicinone, 7 -methoxyvasicinone, vasicinol, adhatodine, adhatonine, adhavasinone, anisotine, 3- hydroxyanisotine, desmethoxyaniflorine, vasicoline and vasicolinone.6-9 The root contains vasicinol, vasicinolone, vasicinone, adhatonine'o. and vasico1.
Oaucosterol, a-amyrin and epitaraxerol are present.
Apigenin, astragalin, kaempferol, quercetin, vitexin, isovitexin, violanthin, 2" -O-xylosylvitexin, rhamnosylvitexin, 2' -hydroxy-4-glucosyloxychalcone are present in the leaf and flower.
The flower volatile oil contains a ketone identified as 4-heptanone as the major compound, together with at least 36 other components including 3-ethylheptanone.'4
The leaf oil is a complex mixture of over 50 compounds, the major component being decane, together with the hydroxyalkanes 37 -hydroxyhexatetracont-l-en-15-one and 29-methyltriacontan-l-ol and linolenic, arachidonic, linoleic, palmitic and oleic acids.
Bronchodilatory and antiasthmatic activity: Vasicine showed bronchodilatory activity both in vitro and in vivo, the activity being comparable to that of theophylline. Vasicinone, however, showed bronchodilatory activity in vitro but bronchoconstriction in vivo. The two alkaloids in combination had a more potent bronchodilatory activity and the combination of vasicinone with aminophylline also had an additive effect. Adhatoda vasica reduced ovalbumin and PAP-induced allergic reactions. A fraction containing the minor alkaloid vascinol and about 20% vasicine inhibited ovalbumin-induced allergic reactions by about 37% at a concentration of 5 mg.
Antibacterial activity: A methanolic extract of the leaves was investigated for antibacterial activity using the paper disc and dilution methods. The in vitro screening showed a strong activity of the alkaloid fraction against Pseudomonas aeruginosa (MIC=16411g/ml). Significant antibacterial activity against the Gram-positive bacteria Streptococcus faecalis, Staphylococcus aureus, Staph epidermidis and the Gram-negative E. coli was also noted. In another study the plant was tested for inhibition of bacterial population of untreated water (in vitro). At pH 7, growth of the bacterial population was inhibited by 82% and at pH 6.5, various coliforms were also inhibited, suggesting a possible use for the plant in the improvement of drinking water.
Antitubercular activity: Bromhexine and ambroxol are semi-synthetic derivatives of vasicine, an alkaloid from Adhatoda vasica, and are widely used as mucolytics. They also have a pH-dependent growth inhibitory effect on Mycobacterium tuberculosis. This, combined with indirect effects including enhancement of lysozyme levels in bronchial secretions and levels of rifampicin in lung tissue and sputum, suggests a useful adjunctive role in the therapy of tuberculosis.
Cholagogue activity: In acute experiments on cats and chronic experiments using dogs, peganine (vasicine) at an N dose of 5 mg/kg had a cholagogue action. In dogs, the amount of excreted bile increased by 40-100%, with a tendency towards dilution of the bile and an increase in bilirubin excretion.
Antidyspepsia activity: A syrup of Adhatoda vasica improved symptoms of dyspepsia. Insecticidal activity: Adhatoda vasica leaves were found to control insect pests in oil seeds, in both laboratory and warehouse conditions. In another study, vasicinol produced antifertility effects in Dysdercus koenigii and Tribolium castaneum, due to blocking of the oviduct. Feeding deterrence was observed against Aulacophora joveicollis and Epilachna vijintioctopunctata at 0.05% and 0.01 % levels. The essential oil showed insecticidal activity against granary pests, e.g. Sitophilus oryzae, Rhizopertha dominica and Bruchus chinensis, and also juvenile hormone mimicking activity in Dysdercus koenigii. It exhibited repellent activity against oryzae and B. chinensis.
Abortifacient and uterotonic activity: Vasicine showed an abortifacient effect in guinea pigs (although not in rats), depending on the stage of pregnancy. The effect was more marked under the priming influence of oestrogens, indicating that the action of the vasicine was probably mediated via the release of prostaglandins. Vasicine also has a uterotonic activity in various other species, including humans, again influenced by the degree of priming ofthe uterus by oestrogens. It initiated rhythmic contractions of human myometrial strips from both non-pregnant and pregnant uteri and the effect was comparable with that of oxytocin.
Wound-healing activity: In a small study, 12-18-month-old male buffalo calves were randomly divided into four groups of three animals each. Six wounds were created on either side of the vertebral column in each animal. The wounds were treated with powdered plant, alcoholic and chloroform extracts of Adhatoda vasica. An increase in rate of healing, breaking strength, tensile strength, absorption and extensibility was observed and collagen, elastin, hydroxyproline, hexosamine and zinc in biopsy specimens significantly increased from the third to the 30th day in the treated groups. The alcoholic extract was the most effective.
Large doses cause diarrhoea and vomiting and because of the uterotonic activity it should not be used during pregnancy. The LDso for vasicine in mice via different routes are: 290 (PO), 125 (IP), 200 (SC) and 79 (IV) mg/kg body weight.