Analgesic and Anti - Pyretic Activities of the Root Bark of Rutidea Parviflora (Rubiaceae)

This study aims at investigating the antipyretic activity of different solvent fractions of the root bark of Rutidea parviflora (Rubiaceae). This plant is used ethno - botanically by the people of Ethiope East - West Local Government Area of Delta State, Nigeria to treat various ailments such as inflammation, fever and pain. This necessitated this research to validate its local use, due to the scanty literature and information present about this plant. It has also shown some anti - cancer and anti - inflammatory activity in previous researches. The present study is a randomized control study. Acetic acid induced writhing was employed for analgesic testing. Acetic acid was used to induce writhing in Wistar rats which were divided into fourteen (14) groups. The groups were administered extracts and fractions of the plant (200 mg/kg and 400 mg/kg). The animals were observed for number of writing movements and the percentage writhing was calculated. Baker ’ s yeast induced pyrexia was employed for the antipyretic testing. The animal groups were administered extracts and fractions of the plant (200 mg/kg and 400 mg/kg), with Paracetamol as the standard drug (100 mg/kg) and Normal saline (control) for both experiments. The body temperature of the rats was measured rectally over a period of five (5) hours. All values of P<0.05 were taken as significant. The organic extract, aqueous extract and various fractions (n - hexane, ethyl - acetate, n - butanol and aqueous) produced significant inhibition of writhing responses and pyrexia in a dose dependent manner and time dependent manner respectively. The aqueous extract at a dose of 400mg/kg showed the greatest reduction in writhing, 91.58% compared to the standard drug (paracetamol) which may suggest that the fraction possesses better efficacy than paracetamol as an analgesic. The observed activities could be attributed to these bioactive compounds: Palmatine, Urs - 12 - ene - 24 - oic - 3 - oxo - methyl ester and Gallic acid contained in R. parviflora.

Another related specie; Nauclea latifolia Smith (Rubiaceae) a small tree, native to Africa and used in traditional medicine by several indigenous communities for the treatment of fever, malaria, pain, epilepsy and anxiety has been found to induce hypothermia with significant antipyretic effects in mice. Also significant antinociceptive activity was recorded in all analgesia animal models used 4 .
Recently, Nauclea latifolia was investigated for its anti-pyretic, anti-nociceptive and anti-inflammatory activities in two animal models. The researchers' documented significant outcomes in all the activities evaluated in a dose-dependent manner 1 .
There are scanty reports on the activities of R. parviflora. One study has documented the anti-cancer activity of this plant; R. parviflora 5

Baker's Yeast Induced Hyperthermia in Rats
The method established by Tomazetti et al, 2005 12 , with some modifications was employed in the antipyretic activity evaluation, with fever induced by Brewer's yeast in rats. The basal rectal temperature of each rat was recorded at zero hour using clinical digital thermometer. Pyrexia was induced by subcutaneous injection of 15% w/v suspension of Brewer's yeast in distilled water at a dose of 10 ml/kg body weight. In order to ensure uniform spreading of the suspension beneath the skin, the injection site was massaged.
Immediately after yeast administration, food was withdrawn but access to water was still maintained. • Groups V and VI received aqueous extract at oral dose of 200 mg/kg and 400 mg/kg respectively.
• Groups VII and VIII received n-hexane fraction at oral dose of 200 mg/kg and 400 mg/kg respectively.
• Groups IX and X received ethyl acetate fraction at a dose of 200 mg/kg and 400 mg/kg po respectively.
• Groups XI and XII received n-butanol fraction at a dose of 200 mg/kg and 400 mg/kg po respectively.
• Groups XIII and XIV received aqueous fraction at oral dose of 200 mg/kg and 400 mg/kg respectively.
After the treatment, the temperature of all the rats in each group was recorded at 0, 1, 2, 3, 4 and 5 hours.

Analgesic Activity
Acetic Acid Induced Writhing Test The method described by Koster et al, 1959 13 , was used for the evaluation of analgesic activity in rats.
The experimental animals were weighed and randomly divided into 14 groups consisting of 5 rats in each.
Group I (control) received normal saline (10 ml/kg) orally. Group II (positive control) received standard drug Paracetamol at oral dose of 100 mg/kg. Remaining groups were treated orally as follows: • Groups III and IV received organic extract at doses of 200 and 400 mg/kg respectively.
• Groups V and VI received aqueous extracts at doses of 200 and 400 mg/kg respectively.
• Groups VII and VIII received n-Hexane fractions at doses of 200 and 400 mg/kg respectively.
• Groups IX and X received ethyl acetate fractions at doses of 200 and 400 mg/kg respectively.
• Groups XI and XII received n-Butanol fractions at doses of 200 and 400 mg/kg respectively.
• Groups XIII and XIV received aqueous fractions at doses of 200 and 400mg/kg respectively.

Antipyretic Test Result
The results of the anti-pyretic evaluation of the extracts and fractions of R. parviflora are presented in Table 3  The analgesic effects of the extracts/fractions of R. parviflora were investigated and the results obtained are presented in Table 4, Figure 3 and 4 respectively.

Analgesic Test Result
The results of the analgesic experiments carried out are displayed in Table 4