Oroxylum indicum (SYonaka)

It is one of the important trees included under Dasamula group (Sothahara group). Caraka described two plants Katvanga and Syonaka together (C.S.Ci. 15/134) wherein Chakrapani commented it as two varieties of Syonaka. The synonym Aralu/Araluka may be one of the reasons for the controversy over this plant. Usually Aralu is identified as Ailanthus excelsa. Dalhana commented Katvanga as the synonyms of Aralu. Sodhala described Syonaka (Aralu) and Tintuka. The former is Kaphahara, Grahi, Dipani, Krimighna and Kushthagha while the later is Vatahara, Vrishya, Sothahara and Agni-bala vardhana. More over, in A.H.Ci. 9/79 the bark of Dirghavrnta and in A.H.Ci. 9/81 Katvanga have been used in diarrhoea. This may provide some support to the view that Katvanga is different from Dirghavrinta (Syonaka). Raja Narahari quoted Syonaka yugala. Bhavamishra documented that unripen fruit of Syonaka is Vata-Kaphahara and ripen fruit is Vatavardhaka.

In Kerala another species of Syonaka possessing smaller leaves is considered as a variety of Syonaka which is identified with Millingtonia hortensis.

Botanical Description–

Big tree, 8-14 m high. Leaves– Opposite, ternately bipinnate; leaflets ovate, entire, acuminate; peduncle about 30 cm long, thick. Flowers– in racemes (25 cm long), foetid; fleshy calyx; corolla fleshy, campanulate, purplish; stamens shortly exserted, fifth filament shorter than the other four. Fruits– large-linear compressed capsules, septicidally bi-valved. Seeds– discoid, thin, wing hyaline and broad.  Flowers and fruits during July-November.

Distribution– Found in the warmer parts of India (upto 1000 m.). Also cultivated as an avenue tree.

Major Chemical Constituents–

Baicalein, Tetulin, oroxindin, aloe-emodin, Chrysin, 6-methylether of baicalein oroxylium A; p-coumaric acid, -arein-7-rutinoside, prunetin, β-sitosterol etc.

Part Used– Root bark.

Dosage– Powder 3-6 g, decoction 40-80 ml

Research–

(1) The bark decoction showed good diuretic activity in rats, comparing favourably with potassium acetate and being more potent than urea (Gujral et al., 1955).

(2) The ethanolic extract (50%) of the fruit showed spasmogenic action on isolated guinea pig ileum (Dhar et al., 1968).

(3) In a preliminary, uncontrolled clinical study on 21 confirmed patients of intestinal amoebiasis, the oral administration of O. indicum (concentrated aqueous extract powders led to symptomatic improvement as well as absence of Ent. Hystolytica cysts in the stools in 19 patients (Mishra & Sharma, 1973).

(4) Bark extract decreased capillary permeability in rats sensitized by egg albumin. It suppressed inflammation caused by egg albumin in intact and sensitized rats (Rast. Resur. 1967, 3, & 46).