Arka (Calotropis procera)
Arka is one of the herbs mentioned in all ancient scripts of Ayurveda. Dhanvantari Nighantu and Madanadi Nighantu have mentioned only two varieties of arka, namely : arka and alarka (rajarka). But Bhavaprakasa after describing two kinds of arka says that there is another variety called raktarka and describes its properties separately. The author of Raja Nighantu also enumerates three kinds of arka viz. arka, vetarka and rajarka and ascribes all of them separately.
However, only two varieties of arka are commonly met with, one with white flowers (Calotropis procera) and the other with lilac, rosy or purple tinted flowers (Calotropis gigantean). In Ayurvedic texts the white flowered varieties called alarka are said to be of superior quality, though all the commentators are of the opinion that either of these can be used with equal effect, as both have the same properties. Maharsi Caraka has categorized arka as bhedaniya- accumulation breaking herb, svedopaga – an adjunct to sweating therapy and vamanopaga – an adjunct to emesis (Caraka Samhita, Sutra, A-4). It is cited to be useful for external application, in ascites. (Astanga Sangraha, Cikitsa, 17).
Arka grows throughout India, especially in dry waste lands. It is a shrub reaching 3-5 metres in height, with thick twisted branches. The young branches are bluntly quadrangular and the bark is ash coloured, covered with a white woolly down. The leaves are large, opposite, spreading, decussate, whitish green in colour, 10-15 cm long and 3-7 cm broad. They resemble to those of banyan tree. The flowers are rather large, beautiful lilac or purple tinged, arranged in umbellate corymbs on erect cylindrical stout peduncles. The fruits are short, stout peduncles. The fruits are short, ovoid, curved, thick, fleshy follicles covered with white woolly pubescence.
As mentioned above, the white flowered variety is botanically named as Calotropis procera and the other with lilac, rosy or purple tinted flowers as Calotropis gigantean. They belong to family Asclepiadaceae. From the leaves of Calotropis procera, calotropin, calatoxin, uscharin and uscharidin have been isolated from latex. Calotropin shows digitalis like action on the heart, but its action is not cumulative and is less harmful. From the flowers, cyaniding – 3 rhamnoglucose and new triterpenecalotropenyl acetate is isolated. Lupeol is isolated from latex. Quercetin-3-rutinoside is identified in the roots, stem, leaves, flowers and latex. Voruscharin is isolated from African plant. Cardenolides contents in leaf (2.04 mg / g ) and in latex (162.0 mg/g) , mostly calotropagenin – derived cardenolides present from Calotropis gigantean, two triterpene esters – 3 methylbutanoates of amyrin and taraxasterol isolated from latex. Calotosin uscharin and calactin have been also identifiedProperties
Arka is pungent and bitter in taste (rasa) pungent in the post digestive effect and has hot potency (virya). The white flowered variety alleviates kapha and vata dosa. Whereas red variety alleviates kapha and pitta dosas. It possesses light (laghu), dry and sharp attributes. The chief properties of arka are emetic, purgative, appetizer, digestant, irritant, poisonous and abortificient. It is used in ascites, tumours and dermatoses. (Bhavaprakasa Nighantu)
The root skin, latex, flowers, leaves and the ksara of arka are used for medicinal purpose. Arka is useful both, internally as well as externally. The poultice of its leaves effectively reduces the pain and swelling in rheumatic joints and filariasis. The medicated oil is beneficial in otitis and deafness; The topical sprinkle of dried leaves powder hastens the wound healing. In glandular swellings the topical application of latex reduces the inflammation. In skin diseases, associated with depigmentation, the latex combined with mustard oil, works well. The fomentation with its leaves, slightly warmed with thin coat of castor oil, is beneficial to relieve the abdominal pain. The local application of latex is recommended in hairfall and baldness. It also, is useful in piles. The latex also mitigates the dental aches.
Internally, arka is very useful many diseases, especially in ascites. The latex as a strong purgative and accumulations breaking imparts excellent results in ascites of kapha type and hepatosplenomegaly with ascites. To alleviate the oedema in such conditions, of kapha origin, the decoction of its roots combined with triphala and honey, is salutary. In asthma and cough, the flowers and the root skin of arka are commonly used. As a blood purifier, it is benevolent is filariasis and syphilis, The red flowers alleviate raktapitta. In chronic dermatoses, the root skin is recommended with honey.
The large doses of its latex and leaf juice produces toxic symptoms like burning in throat, irriation of the stomach, nausea, vomiting, diarrhoea, tremors, vertigo and convulsions. In these conditions, withdraw the use of arka or its preparations and advise the milk and ghee in diet.Classical Ayurvedic Preparations
- Arka taila
- Arkadi curna
- Sutikabha rana
- Pravala pancamrta
- Arkakolakanda vati etc.