Arka consists of dried roots of Calotropis procera (Ait.) R. Br. (Fam.
Asclepiadaceae) found wild more or less throughout India.
Sanskrit : Ravi, Bhanu, Tapana
Assamese : Akand, Akan
Bengali : Akanda, Akone
English : Madar Tree
Gujrati : Aakado
Hindi : Aak, Madar, Akavana
Kannada : Ekka, Ekkadagida, Ekkegida
Kashmiri : Acka
Malayalam : Erikku
Marathi : Rui
Oriya : Arakha
Punjabi : Ak
Tamil : Vellerukku, Erukku
Telugu : Jilledu
Urdu : Madar, Aak
Root-rough, fissured longitudinally, corky and soft, externally yellowish-grey
while internally white, central core cream coloured, bark easily separated from xylem,
odour, characteristic: taste, bitter and acrid.
Transverse section of root shows outer most cork tissue consisting of 4-8 rows of
tangentially elongated and radially arranged cells followed by 3-6 rows of moderately
thick-walled, irregular cells of secondary cortex devoid of calcium oxalate crystals and
starch grains, cortex composed of large polyhedral parenchymatous cells containing
abundant rounded starch grains, some cortical cells contain rosette crystals of calcium
oxalate, scattered laticifer cells with brown contents, phloem consists of sieve elements
and phloem parenchyama, sieve tubes thick-walled, cells more prominent towards inner
region of phloem traversed by uni to tetraseriate medullary rays, phloem cells contain
crystals of calcium oxalate, starch grains and laticifers similar to these found in cortex:
cambium present just within the phloem consisting of 2-5 rows of thin-walled,
tangentially elongated cells xylem forms the central part of root composed of vessels.
11tracheids, fibres and xylem parenchyma, vessels present throughout xylem region and
arranged radially in groups of 2-7, sometime single vessels also occur, usually
cylindrical having bordered pits on their walls, xylem fibres long, lignified with wide
lumen, tapering on ends and have simple pits on walls, medullary rays 1-4 seriate and
triseriate in outer region and uni or biseriate in inner region: cells of medullary rays
radially elongated, filled with starch similar to those present in cortical cells.
IDENTITY, PURITY AND STRENGTH
Foreign matter Not more than 2%,
Total Ash Not more than 4%,
Acid-insoluble ash Not more than 1%,
Alcohol-soluble extractive Not less than 2%,
Water-soluble extractive Not less than 8%,
CONSTITUENTS – Glycosides (calotropin).
PROPERTIES AND ACTION
Rasa : Katu, Tikta
Guna : Laghu
Virya : Usna
Vipaka : Katu
Karma : Dipana, Kaphavatahrt, Bhedana, Krmighna, Vranahara, Visaghna,
IMPORTANT FORMULATIONS – Mahavisagarbha Taila, Dhanvantara Ghrta
THERAPEUTIC USES – Gulma, Krmiroga, Kandu, Kustha, Udararoga, Vrana, Svasa
DOSE – 1-3 g of the drug for decoction.