Analgesic effect of extract of clerodendron bungei steud roots in mice

Jianxin LIU; Shuixiang XIE; Li ZHOU; Qishen LIAN

ABSTRACT

BACKGROUND:

Clerodendron bungei steud(CBS) is a tree from genera of Verbena L. In the present pharmacological studies, CBS has showed anti-inflammatory, antineoplasic, nonspecific immunity-enhancing effects. Myoelectric effect of stimulating uterus round ligament is related with agitating adrenergic α receptor. The experiments about analgesic effect are few.

OBJECTIVE:

To observe the antinociceptive effect of ethanol extract of CBS in mice through hot plate and writhing tests.

DESIGN:

Randomized controlled experiment with animals as subjects.

SETTING:

Departmcent of Pharmmacology, Gannan Medical College.MATERIALS The experiment was performed in Department of Pharmacology, Gannan Medical College from March to June 2004. A total of 120Kunming white mice, weighing(20 ± 2) g were provided by the Experiment Animal Center of Gannan Medical College.

INTERVENTIONS:

In the writhing test, 50 mice were randomly divided into normal saline, aminopyrine group(0. 1 g/kg), morphine group(0.01 g/kg)and extract of CBS groups(20 g/kg, 40 g/kg) . There were 10 mice in each group. Forty minutes after intraperitoneal injection. 6 mL/L acetic acid (10 mL/kg) was injected intraperitoneally, 5 minutes later, the number of writhing body and inhibitory rate of writhing body were observed for 10minutes. In hot plate test, 40 mice were randomly divided into normal saline group, morphine group(0.01 g/kg) and extract of CBS groups(20 g/kg,40 g/kg). There were 10 mice in each group. After intraperitoneal injection,the mice were put on the hot plate, and the temperature was(55 ±0.5) C. The pain threshold was recorded 15, 30 and 60 minutes after administration. And 30 white mice were randomly divided into naloxone 0. 04 g/kg + morphine 0.01 g/kg group, aloxone 0.04 g/kg + extract of CBS 40 g/kg group,naloxone 0.04 g/kg + normal saline group for hot plate test antagonized by naloxone(40 mg/kg) . The mice were injected intraperitoneally. The duration of pain reaction were recorded 15, 30, 60 and 90 minutes after administration.MAIN OUTCOME

MEASURES:

① The number of writhing body and inhibitory rate of writhing body; ② The duration of pain reaction; ③ The pain threshold in the hot-plate test after antagonized by naloxone were calculated.

RESULTS:

All the 120 white mice entered the result analysis. ① The number of writhing body and inhibitory rate of writhing body The number of writhing body was 2.4 ± 2.5 and 0. 6 ± 1.7 in the 20 and 40 g/kg extract of CBS injection group respectively and the inhibitory rate of the pain reaction caused by 6 mL/L acetic acid was 93.3% and 98.3% respectively. ② The pain threshold at 15, 30 and 60 minutes after administration in the hot plate test the pain threshold was[(121.2±98.7) s, (191.2±78.6) s,(133. 1 ± 91.1 ) s] at 15, 30 and 60 minutes after injection of 20 g/kg extract of clerodendron bungei steud; it was[(233.9 ±70.4) s, (219.6 ±78.2) s,(218.3 ±92.6) s at 15, 30 and 60 minutes after 40 g/kg extract of CBS being given. The pain threshold in the extract of CBS groups was all higher than that in the control group respectively[ (13.7 ± 15.2) s, (9.7 ± 12.5) s,(22. 1 ± 15.6) s] ( P ＜ 0.01 -0. 001) . ③ In naloxone antagonized morphine test, the pain threshold at 15, 30 and 60 minutes after administration in morphine 0.01 g/kg+naloxone 0.04 g/kg group[(1.7±5.2) s (6.4 ± 8.6) s, (21.8 ± 34.0) s]was obviously smaller than that in the extract of CBS 40 g/kg +naloxone 0. 04 g/kg group[(124.9 ±79.4) s,(139.3±72.9) s, (137.9±60.8) s](P ＜0.001).

CONCLUSION:

Ethanol extract of CBS has strong analgesic effect and this is not manifested through the activation of opioid receptors.