**7. A case of substitution in Nepal**

Rohitaka is mentioned in almost all classics of Ayurveda such as Brihattrayee (Charaka Samhita, Sushruta Samhita, and Ashtanga Hridya) and other lexicons such as Sharangdhara Samhita, Bhavaprakasha Nighantu, and Yoga Ratnakar. It is also mentioned in maximum numbers of Nighantu (Ayurvedic lexicons). It is mentioned as Yakritpleehagulmodar Roga-hara (useful in liver diseases, spleen disorders, and abdominal lumps). Tecomella undulata (Sm.) Seem. from Bignoniaceae family is a genuine source of Rohitaka. It is commonly known as "Rohida" or "Desert Teak" and an important deciduous, ornamental, and medicinal tree [19].

In crude drug market of Nepal *Rhododendron arboreum* Sm. is sold by the name of Rohitaka and considered as substitute of *Tecomella undulata* (Sm.) Seem. The Nepali name of Rohitaka is given as Guransa in Chandra Nighantu which is a hand written famous manuscript in Nepal and kept in Singha Darbar Vaidyakhana Vikas Samiti (SDVKVS) in Kathmandu. In this manuscript manually drawn picture of Rohitaka is given which is Guransa and is botanically identified as *Rhododendron arboretum* Sm. Traditional practitioners use this drug for liver disorders like Jaundice (Kamala), hepatitis, hepatomegaly etc. Leaves, flowers, bark are used for various purposes traditionally and in Ayurvedic practices [19].

The genuine source of Rohitaka is identified as *T. undulata* (Sm.) Seem. However, due to non-availability of the genuine source, various other drugs are used as substitute. Stem bark of *R. arboreum* Sm. is commonly found by the name of Rohitaka in herbal raw drugs trade in Nepal. The rationality behind selection of Pratinidhi Dravya (substitute drug) isbased on similarity in Rasa, Guna, Veerya, and Vipaka with that of original drug. On organoleptic evaluation, both drugs are bitter in taste substantiated the similarity in Rasa. The pharmacognostic and analytical studies have confirmed the genuinity and purity of both the drugs (*R. arboreum* Sm. and *T. undulata* [Sm.] Seem.). Both the drugs have few common phytochemicals such as carbohydrates, alkaloids, tannins, and phenols which are responsible for their pharmacological actions. Chromatographic study showed

the presence of 18 phytoconstituents in *R. arboreum* and 24 phytoconstituents in *T. undulata* extracts, and among them, three phytoconstituents having Rf of 0.30. 0.45, 0.66 are common [22].
