ANTIANXIETY PROPERTY OF BASELLA ALBA LINN LEAVES EXTRACT IN EXPERIMENTAL ANIMALS - DISUCSSION

 

6. DISCUSSION

 

The purpose of this dissertation was to evaluate anxiolytic activity of Basella alba leaves Extract. Many natural products derived from plants have been used for centuries to cure or treat diseases. Basella alba L. is reported to contain a flavonoids^,31,32; more specifically kaempferol(kaempherol) type of flavonoid³². Kaempferol is reported to exert an anxiolytic (anti-anxiety) activity in plants like Tilia americana ^25,26 and apocynum venetum³³.

Drugs from natural origin are playing vital role in correcting ill health of human since the times immemorial. Inspite of the scintillating advancement with the modern medicines, the disease like jaundice has to be treated with the herbs and herbal preparations only. There are even claims that herbs and herbal preparations are safer than the synthetic drugs.

The purpose of this study was to evaluate the anxiolytic effect of aqueous and ethanolic extracts of Basella alba leaves by using behavioural animal models of anxiety. The major finding of present investigation propose the anxiolytic activity on elevated plus maze test in mice, hole and board test in rats, light/dark transition test in mice and open field test.

The elevated plus maze (EPM) is currently one of the most widely used model of animal anxiety and it’s validated and use in rats and mice¹³⁶. In EPM, mice will normally prefer to spend much of their allotted time in the closed arms. This preference appears to reflect an aversion towards open arms that is generated by the fears of the open spaces. Drugs that increase open arm exploration are considered as anxiolytics and the reverse holds true for anxiogenics¹⁷⁷ The EPM test is based on a premise where the exposure to an EPM evoked an approach-avoidance conflict that was considerably stronger than evoked by the exposure to an enclosed arm⁴. The decrease in aversion to the open arm is the result of an anxiolytic effect, expressed by the increased time spent and entries in to the open arm are sensitive to agents thought to act via the GABA_A receptor complex, justifying the use of diazepam as a positive control in this study ¹³³, even when the compound being screened does not act via benzodiazepine receptors.

            Diazepam increases the percentage of entries and the time spent in the open arm confirms its anxiolytic effects. The aqueous and ethanolic extract of Basella alba leaves had similar effects on these parameters. The both extract at 400 mg/kg did not alter the above parameter significantly, therefore it does not exhibit anxiolytic effect. The aqueous extract at 800 mg/kg showed increase percentage of time spent and entries in open arm, decreased the percentage of time spent in close arm but the percentage of entries in close arm was not decreased whereas the ethanolic extract at EE 800 mg/kg produced significantly decreased the percentage of entries in close arm also as compare to control. Both the extract at 800 mg/kg have increased the percentage time spent and entries in to open arm with decreased in closed arm significantly (p< 0.01) as compare to control group.

It can be suggested that 800 mg/kg doses ethanolic extract may have the anxiolytic effects similar to the standard drug.

 Therefore behavioural alteration induced by higher dose of 800 mg/kg shows dose dependant anxiolytic profile.

The hole and board test provides a simple method for measuring the response of an animal to an unfamiliar environment and is widely used to assess emotionality, anxiety and/or responses to stress in animals. The head dipping behaviour was sensitive to changes in the emotional state of the animal, and suggested that the expression of the anxiolytic state in animals may be reflected by an increase in head dipping behaviour ¹⁰⁰.   

Diazepam decreased the head dip latency and locomotion significantly (p < 0.001), and increase the head dip count significantly (p < 0.001) as compare to control group. Ethanolic extract at 800 mg/kg had significantly decreased locomotion also (p < 0.01). Aqueous extract at 800mg/kg had significantly decreased head dip latency (p < 0.001), locomotion (p < 0.01), and increased in head dip count significantly (p < 0.001) likewise ethanolic extract at 400 and 800mg/kg had significantly decreased the latency to head dip, locomotion (p < 0.01) and increased in head dip count (p < 0.001).  Therefore the increased head dip count, decreased head dip latency, and locomotion is representation of anxiolytic effects.

Light and dark box is another widely used rodent anxiety model for screening anxiolytic or anxiogenic drugs. It is based on the innate aversion of rodents to brightly illuminated areas and on the spontaneous exploratory behaviour of rodents in response to mild stressors that is novel environment and light ¹⁷⁴.  Drugs induced increase in behaviour in the white part of a two compartment box, in which a large white compartment is illuminated and a small black compartment is darkened, is suggested as an index of anxiolytic activity ¹⁷⁵. In this study, the time spent in light area, latency to enter dark chamber and tunnel crossing is an indices of anxiety.

Diazepam at 2 mg/kg had significantly increased the latency to enter dark chamber, time spent in light chamber and decreased tunnel crossing as compare to control group. The ethanolic extract at 400 and  800 mg/kg had increased the latency to enter dark chamber, time spent in light area, and decreased tunnel crossing significantly (p < 0.05.

In Open field test EE 400 mg/kg, 800 mg/kg and AE 800 mg/kg are increasing total locomotion significantly. EE 400 mg/kg, 800 mg/kg and AE 800 mg/kg are decresing numbers of rearing significantly. EE 400 mg/kg, 800 mg/kg and AE 800 mg/kg are decresing immobility significantly. EE 800 have shown nearly equal results to Diazepam.