Karavira consists of dried leaves of Nerium indicum Mill. Syn. Nerium odorum Soland (Fam.Apocynaceae), a large evergreen woody shrub with milky Juice, found throughout the year in upper Gangetic plains, Himalayas, from Nepal to Kashmir upto 2000 m. Central and Southern India, also cultivated near temples and gardens.
Sanskrit : Hayamiraka, Harapriya, Asvamira.
Assamese : Karbira, Karavi, Karvir
Bengali : Karavi, Kalkephul
English : Indian Oleander
Gujrati : Kanera, Karena, Karen
Hindi : Kaner
Kannada : Kanagalu, Kanagile
Kashmiri : Gandeela, Gandula
Malayalam : Kanave eram, Arali, Kattalari
Marathi : Kanher
Oriya : Kaniara, Kaniar
Punjabi : Kaner
Tamil : Arali, Alari, Aatrulari
Telugu : Ganneru
Urdu : Kaner
Leaves exstipulate, linear, lanceolate, 10-20 cm long and upto 2.5 cm wide, thick, dark green and shining above and dotted beneath, venation unicostate, reticulate with midrib being stout and the secondary veins arising in very large number, running parallel, stomata anamocytic.
Petiole-transverse section of petiole shows a single layer of epidermis covered externally by thick cuticle, epidermal cells elongate to form unicellular, non-lignified and nonglandular hairs, a wide zone of cortex, composed of 4-7 layers of collenchymatous cells and a Wide zone of parenchyma follows the epidermis, parenchymatous cells thinwalled, more or less isodiametric with intercellular spaces, some cells contain rosette crystals of calcium oxalate, petiole receives three vascular bundles from stem, central one large and crescent shaped while other two much smaller and somewhat circular present on each side of central vascular bundle, phloem present on upper side and xylem on lower Side With usual elements.
Lamina-transverse section of lamina shows an isobilateral structure, upper epidermis composed of penta or hexagonal parenchymatous cells, externally covered with thick cuticle, below upper epidermis. 2-3 layers of hypodermis present, palisada 3-4 layered composed of elongated and compactly arranged cells, vascular strands also seen in between palisade and spongy parenchyma, spongy parenchyma filled with chlorophyll, towards lower surface 2-3 layered palisade, below which parenchyma and lower epidermis present, lower epidermis also coated with the cuticle externally, in lower surface many pits possessing stomata, unicellular, non-glandular and non-lignified trichomes, rosette crystals of calcium oxalate present throughout lamina, average palisade ratio 4: 1.
Midrib-transverse section of midrib shows epidermis composed of a layer of cells, externally covered with cuticle, some epidermal cells on upper and lower sides form unicellular hairs, between epidermis and parenchyma 2-4 rows of thick-walled cells, more prominent towards lower side, some parenchymatous cells contain rosette crystals of calcium oxalate, laticifers found scattered singly or in groups of 2 in this region, beneath the vascular bundle a sn ip of fibres present, vascular bundle ‘U’ shaped, xylem being towards lower side and phloem towards the upper consists of tracheids, vessels and parenchyma, vessels with end-openings, rarely with side openings tracheids many with spiral, annular or reticulate thickenings on their walls.
CONSTITUENTS – Cardiac glucoside (oleandrin).
PROPERTIES AND ACTION
Rasa : Katu, Tikta, Kashiya
Guna : Laghu, Ruksha, Tikshna
Virya : Ushna
Vipaka : Katu
Karma : svisahara, Cakshushya, Krimighna, Kandhughna, Kushhaghna, Vranipaha, Jvaripaha
IMPORTANT FORMULATIONS – Kisisidi Taila
THERAPEUTIC USES – Hridroga, Jvara, Krimiroga(Antihelmenthic), Kandhu(Itching) Kushtha, Netraroga, Vrana,Tamak
DOSE – 30-125 mg of the drug in powder form.
*Dose should not exceed the higher limit.