Abstract:
An unboiled water extract (UBE) of stems and
leaves of Psychotria sarmentosa Blume (Family: Rubiaceae)
is drunk by some men in Sri Lanka after being physically
assaulted, indicating that it may have potent analgesic and/or
anti-inflammatory activity. However, these activities are not
described in either the Sri Lankan Ayurveda Pharmacopoeia
or the Deshiya Chikithsa system of medicine practised in Sri
Lanka. The aim of this study was to investigate whether an
UBE of these parts of P. sarmentosa has such activities.
Different doses of the UBE (7.5, 15.0 and 22.5 ml/kg) or
vehicle were administered orally to rats. 1 and 3 h later, the
analgesic potential was determined using hot plate and tail
flick tests. In another set of rats, the highest dose of UBE was
orally administered, and paw oedema induced with 1% carrageenan.
Anti-inflammatory activity (up to 4 h) and antihyperalgesic
activity (at 1 h) were determined (by the hot plate
technique). All the doses of UBE were well tolerated and the
highest had potent analgesic activity (in both tests, in terms
of reaction time and % maximum possible effect) and antihyperalgesic
activity (measured 1 h post-treatment). The
UBE had no anti-inflarmnatory activity. Its analgesic activity
was comparable to that of indomethacin and was not blocked
by naloxone, (opioid receptor blocker), metochlopramide
(dopamine receptor blocker) or atropine (cholinergic receptor
blocker). We conclude that the antinociceptive activity of the
UBE was mediated both spinally and supraspinally, and the
antihyperalgesic activity spinally. Both actions may have
been mediated through a paracetamol type of action.
Med Sci Res 27:715-718 © 1999 Lippincott Williams & Wilkins
