Arka (root) / Madar tree

Ayurveda – Arka (root)

Arka consists of dried roots of calotropis procera (ait.) r. br. (fam. asclepiadaceae) found wild more or less throughout India.

Synonyms

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

 Description

a) macroscopic

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.

 b) microscopic

transverse section of root shows outer most cork tissue consisting of 4-8 rows of tangentially elongated and radially arranged cells followed

Arka (root) / Madar tree

Arka (root) / Madar tree

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 per cent

total ash                                                               not more than 4 per cent

acid-insoluble ash                                           not more than 1 per cent

alcohol-soluble extractive                          not less than 2 per cent

water-soluble extractive                               not less than 8 per cent

constituents – glycosides (calotropin).

 properties and action

rasa : katu, tikta

guna : laghu

virya : usna

vipaka : katu

karma : dipana, kaphavatahrt, bhedana, krmighna, vra¸ahara, viàaghna, kushaghna

important formulations – mahavisagarbha taila, dhanvantara ghrta

therapeutic uses – Gulma, krmiroga, kandu, kushtha, udararoga, vra¸a, svasa

dose – 1-3 g of the drug for decoction.

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