Evaluation of Antipyretic and Analgesic Effects of Alchornea cordifolia Schum. & Thonn. (Euphorbiaceae) and Quassia africana Baill (Simaroubaceae)

Alchornea cordifolia (Euphorbiaceae) is widely used in Africa for the treatment of malaria, fever, tooth decay, leprosy, amoebic dysentery, hemorrhoids, headaches, venereal diseases and inflammation. It is also used as emmenagogue and oxytocic. Quassia africana (Simaroubaceae) is also widely used in Africa for the treatment of malaria, gastritis, intestinal worms, rheumatism, bronchopneumonia, gonorrhea, headache, tooth decay and tonsillitis. The present study aims to highlight the analgesic and antipyretic effects of both plants. Fever was induced by oral administration of 20 ml / kg of 20% beer yeast in rats 24 hours before treatment. The rectal temperature was measured 1h, 2h and 3h after treatment. The pain was induced by intraperitoneal injection of 0.1 ml / 10 g of 0.6% acetic acid in rats 1 hour after oral treatment. The analgesic activity was assessed for 10 minutes by counting the number of cramps. The aqueous, ethanolic and dichloromethane extracts of the leaves and fruits of Alchornea cordifolia at 400 and 800 mg / kg per os showed a very significant antipyretic effect identical to paracetamol at 100 mg / kg per os. The aqueous extracts of the leaves and fruits of Alchornea cordifolia as well as barks of Quassia africana at 400 and 800 mg / kg per os showed a very significant analgesic effect. These effects are related to the presence of alkaloids and terpenes for Alchornea cordifolia and Quassinoides for Quassia africana.


Plants material
The roots and leaves of Quassia Africana, and leaves and fruits of Alchornea cordifolia collected at Makana village in the Department of the Pool-Congo, were used. These samples were identified in the Congo National Herbarium by botanists from the Botany Laboratory of the Institut National de Recherche en Sciences de la Santé (IRSSEN) of Brazzaville-Congo. A specimen voucher from each sample was deposited and registered under the number QAS003 (Quassia africana) and ACE005 (Alchornea cordifolia).

Preparations of plants extracts
We made a decoction in water and macerations with ethanol and dichloromethane. The decoction was prepared by boiling 25 g of plant material in 250 ml of water at 100 ° C for 30 min. The macerate was prepared by placing 25 g of plant material (leaves and fruit) in 250 ml of organic solvents (ethanol or dichloromethane). The mixture was stirred for 24 h, before being filtered successively with a cotton wool and a filter paper (wattman). The filtrates were concentrated. For experimentation, organic extracts were dissolved in 10% of Tween 80.

Treatments of rats
Rats of the same age, were divided into seven (7) lots of 5 rats each and fasted 24 hours before the experiment. These rats were orally treated as follows:

Treatment of antipyretic effect evaluation
• Lot 1 received the distilled water at a dose of 1ml / 100g of rat body weight; • Lot 1' received the Tween 80 (10%) at a dose of 1ml / 100g of rat body weight; • Lot 2 received the paracetamol at a dose of 100 mg / kg of rat body weight; • Lot 3 received the aqueous leaf extract of Alchornea cordifolia at a dose of 400 mg / kg of rat body weight; Lot 4 received the aqueous extract of leaves of Alchornea cordifolia at a dose of 800 mg / kg of rat body weight; • Lot 5 received the aqueous extract of the fruit of Alchornea cordifolia at the dose of 400 mg / kg of rat body weight; • Lot 6 received the aqueous extract of the fruit of Alchornea cordifolia at a dose of 800 mg / kg of rat body weight; • Lot 7 received the aqueous root extract of Quassia africana at a dose of 800 mg / kg of rat body weight; • Lot 8 received the aqueous root extract of Quassia africana at a dose of 400 mg / kg of rat body weight; • Lot 9 received the ethanolic extract of leaves of Alchornea cordifolia at a dose of 400 mg / kg of rat body weight; • Lot 10 received the dichloromethane extract from leaves of Alchornea cordifolia at a dose of 400 mg / kg of rat body weight; • Lot 11 received the ethanolic extract of the fruit of Alchornea cordifolia at a dose of 400 mg / kg of rat body weight; • Lot 12 received the dichloromethane extract from the fruit of Alchornea cordifolia at a dose of 400 mg / kg of rat body weight.

Evaluation of the antipyretic effect
To each animal fasting for 24 hours, the rectal temperature is measured and orally 20 ml / kg of 20% yeast beer is administered (Nsonde Ntandou et al., 2016) 24 h later, a new rectal temperature is measured (T24h). Animals showing a rise in rectal temperature ≥ 0.5 ° C were selected for study and then treated. After administration of the products, the rectal temperature was further measured after one (1) hour, two (2) hours, and three (3) hours.

Evaluation of the analgesic effect
One hour after administration of the test products, each rat is treated with 0.1 ml / 10 g of 0.6% acetic acid IP and placed in a cage (Nsonde Ntandou et al.,  2018). The analgesic activity is appreciated for 10 minutes by counting the number of cramps (stretching of the legs and dorso-abdominal torsion of the muscles). The result was expressed as percent inhibition calculated according to the formula: % inhibition = 100 (Number of cramps in the control group-number of cramps in the treated batch) / Average cramps

Statistical analyzes
The results are expressed on average ± SD for a number of n = 5 rats per lot using the Microsoft Excel Windows 7 software. The results obtained in the test groups were compared to the control lot using the Student's t test. Significances were established at * p <0.5, ** p <0.01 and *** p <0.001.

Antipyretic effect in rats treated with aqueous extracts of both plants
The administration of 20% brewer's yeast caused an increase in the rectal temperature of 1.2 ± 0.05 of the lots of the rats used in the antipyretic effect evaluation. The figure 1 shows the effect of Alchornea cordifolia aqueous extracts of leaves and fruits, Quassia africana roots at the doses 400 and 800 mg / kg, distilled water (10 ml / kg), and paracetamol (100 mg / kg) on the yeast induced hyperthermia following oral administration. It shows that the 400 and 800 mg / kg of Alchornea cordifolia aqueous extracts of leaves and fruits as well as the reference drug significantly (p <0.01) lowered the rectal body temperature.    Figures 3 and 4 show the effect of products on the acetic acid abdominal cramps. The rats received distilled water, the number of contortions is significantly very pronounced compared with those which were treated with paracetamol at 100 mg/kg and the different aqueous extracts at the doses of 400 and 800 mg /kg.   These results confirm the traditional use of Alchornea cordifolia as antipyretic. This effect is due to the presence of alkaloids, terpenes since these chemical families possess antipyretic properties.

Analgesic effect
From the work done in rats, we could check the analgesic effect of plants extracts. IP injection of 0.6% acetic acid in rats caused a painful effect which was manifested by stretching movements of the hind legs and the dorso-ventral musculature. These cramps which occur after injection of acetic acid are produced by prostaglandin PGE2 and PGF alpha synthesized in the presence of cyclooxygenase-2. Plants extracts expressed their antalgic power by inhibiting the synthesis of prostaglandins. The disadvantage with the chemical method is that the pain can be induced by the injury caused by the needle. Quassia Africana and Alchornea coordifolia extracts, and paracetamol significantly reduce abdominal cramps caused by injection of acetic acid to 0.6%. This reduction of cramps number reveals significant analgesic activity mediated peripherally. Both plants have antalgic effect. However, at a dose of 400 mg/kg, roots extract of Quassia Africana has most interesting antalgic effect than Alchornea cordifolia extracts (400 and 800 mg/kg) and paracetamol (100 mg/kg). The extract from Quassia africana shows that it is more significant at the dose of 400mg / kg than at the dose of 800 mg / kg. This effect is similar with those found with Quassia amara another simaroubaceae (Toma et al., 2003). In our study we exhibited the antalgic effect of Alchorean codifolia in leaves and fruits extracts. This finding is in accordance with Ismaila