=RADIX HEMIDESMI.=
_Hemidesmus Root_, _Nunnari Root_, _Indian Sarsaparilla_.
=Botanical Origin=—_Hemidesmus indicus_ R. Brown (_Periploca indica_
Willd., _Asclepias Pseudo-sarsa_ Roxb.), a twining shrub, growing
throughout the Indian Peninsula and in Ceylon. The leaves are very
diverse, being narrow and lanceolate in the lower part of the plant,
and broadly ovate in the upper branches.[1564]
=History=—In the ancient Sanskrit literature the plant occurs
frequently under the name _Sārivā_, and its root under the name of
_Nannārī_ or _Ananta-mūl_ (_i.e._ endless root) has long been employed
in medicine in the southern parts of India.[1565] Ashburner in 1831
was the first to call the attention of the profession in Europe to
its medicinal value.[1566] In 1864 it was admitted to a place in the
_British Pharmacopœia_, but its efficiency is by no means generally
acknowledged.
=Description=[1567]—The root is in pieces of 6 inches or more in
length; it is cylindrical, tortuous, longitudinally furrowed, from
²/₁₀ to ⁷/₁₀ of an inch in thickness, mostly simple or provided with
a few thin rootlets emitting slender, branching woody aerial stems,
³/₀ of an inch or less thick. Externally it is dark brown, sometimes
with a slight violet-grey hue, which is particularly obvious in the
sunshine. The transverse section of the hard root shows a white mealy
or brownish or somewhat violet cortical layer, not exceeding ⅒ of an
inch in thickness, and a yellowish woody column, separated by a narrow
dark undulated cambial line. Neither the wood nor the cortical tissue
present a radiate structure in the stout pieces; in the thinner roots,
medullary rays are obvious in the woody part. The extremely thin corky
layer easily separates from the bark, which latter is frequently marked
transversely by large cracks. The root, whether fresh or dried, has
an agreeable odour resembling tonka bean or melilot. The dried root
has a sweetish taste with a very slight acidity. The stems are almost
tasteless and inodorous. The root found in the English market is often
of very bad quality.
[1563] _Yearbook of Pharm._ 1878. 624, from _Proc. of the American
Pharm. Association_, 1877.
[1564] Fig. in Bentley and Trimen, _Med. Plants_, part 6 (1876).
[1565] There is an Indian root figured as _Palo de Culebra_ by Acosta
(_Tractado de las Drogas ... de las Indias Orientales_, 1578, cap.
lv.) which is astonishingly like the drug in question. He describes
it moreover as having a sweet smell of melilot. The plant he says is
called in Canarese _Duda sali_. The figure is reproduced in Antoine
Colin’s translation, but not in that of Clusius.
[1566] _Lond. Med. and Phys. Journ._ lxv. 189.
[1567] Taken from excellent specimens obligingly sent to us from India
by Dr. L. W. Stewart and Mr. Broughton.
=Microscopic Structure=—All the proper cortical tissue shows a uniform
parenchyme, not distinctly separated into liber, medullary rays and
mesophlœum. On making a longitudinal section however, one can observe
some elongated laticiferous vessels filled with the colourless concrete
milky juice. In a transverse section, they are seen to be irregularly
scattered through the bark, chiefly in its inner layers, yet even
here in not very considerable number. They are frequently 30 mkm. in
diameter and not branched.
The wood is traversed by small medullary rays, which are obvious only
in the longitudinal section. The parenchymatous tissue of the root is
loaded with large, ovoid starch granules. Tannic matters do not occur
to any considerable amount, except in the outermost suberous layer.
=Chemical Composition=—The root has not been submitted to any adequate
chemical examination. Its taste and smell appear not to depend on the
presence of essential oil, so far as may be inferred from microscopic
examination; and it is probable the aroma is due to a body of the
cumarin class. According to Scott,[1568] the root yields by simple
distillation with water a stearoptene, which is probably the substance
obtained by Garden in 1837, and supposed to be a volatile acid.
=Uses=—The drug is reputed to be alterative, tonic, diuretic and
diaphoretic, but is rarely employed, at least in England.