Monier-Williams: A Sanskrit-English Dictionary (p. 630)
pīlu, m. (cf. Uṇ. i, 38 Sch.) a species of tree (Careya arborea or Salvadora persica, L.) MBh. R. &c.; a group of palm trees or the stem of the palm, L.; a flower, L.; the blossoms of Saccharum sara, L.; a piece of bone (asthi-khanda), L.; an arrow, L.; a worm, L.; an atom Sarvad.; an elephant (cf. Arabic, Persian), L.; (u) n. the fruit of the Pilu tree AV.

Tamil Lexicon, University of Madras (p. 2884)
peruviḷā: Toothbrush tree, m. tr., Salvadora persica

Tamil Lexicon, University of Madras (p. 387)
ukā: 1. Tooth-brush tree, s tr., Salvadora persica; 2. Sandpaper-tree, l. tr. Dillenia indica

Dymock, Warden, Hooper: Pharmacographia Indica (vol. II, pp. 380-382)
Salvadora persica, Salvadora oleoides, Salvadoraceae
The two species of Salvadora grow upon the sea coast of Arabia, Persia and Western India, as well as in the arid districts of the interior. They are the Pilu of Sanskrit writers, and in the Nighantas bear the synonyms of Sahasrā, Karambha-priya, Tatphala, etc. The Hindus consider the fruit to be hot, digestive, lithontripic, fattening and light; and to be beneficial in enlarged spleen, rheumatism, tumours and lithiasis; it is also thought to have alchemic or alterative properties. In Marwar and other parts of Northern India the berries of S. oleoides and S. persica are largely collected and dried in the sun as an article of diet. When dry they resemble grape currants both in appearance and taste. From the seeds an oil is expressed, which is used as a stimulating application in painful rheumatic affections and after childbirth. The leaves of these trees heated and tied up in a cloth with those of Vitex trifolia are a favorite domestic remedy for rheumatic pains.
The Arabs call the Salvadoras Arāk and the Persians Darakht-i-miswāk, "tooth-brush tree," short pieces of the root, about the size of goosequill, being used to clean the teeth. On the coast of Persia bordering the Persian Gulf these shrubs are called Chōch, and are depastured by camels and buffaloes. They are said to render the milk very rich and thick. This property of the plant as a fodder is also known in India. The author of the Makhzan-el-Adwiya describes the fruit as deobstruent, carminative and diuretic, and remarks that a poultice of the leaves, which have similar properties, is used to relieve the pain caused by tumours, piles, &c.
Forskahl (Aegypt-Arab., p. 32) has the following notice of Salvadora: -"In magno est pretio; fructus (Kabath) maturus edulis; folia contusa imponuntur tumoribus 'waram' dictis et bubonibus; sed vis antitoxica adeo famosa, ut carmine quoque celebretur." Kabāth is the Arabic name for the ripe fruit, when unripe is called 'barir.'
Ainslie gives Ooghai-puttai as the Tamil name of S. persica, and says, "the bark, which is a little warm and somewhat acrid, is recommended by the Hindu doctors, in decoction, in cases of low fever, and as a tonic and stimulant in amenorrhoea. The bark of the root when fresh acts as a vesicatory." (Mat. Ind. ii., p. 266.) In the Pharmacopoeia of India, we are told that Dr. Irvine employed the root-bark successfully as a vesicant. In Dr. Imlach's Report on Snake-bites in Sind (Bomb. Med. and Phys. Trans. New Ser., iii., p. 80), several cases are mentioned in the tabular record, in which Pilu seeds were administered internally, with good effect. They are also said to be a favorite purgative.
Royle considers S. persica to be the mustard tree of the New Testament, and says that the Syrian Arabs call it Khardal, i.e. "mustard."