ANTIANXIETY PROPERTY OF TECOMA STANS LINN LEAVES EXTRACT IN EXPERIMENTAL ANIMALS - DISCUSSION

 

6. DISCUSSION

 

            The study was to evaluate the antianxiety effect of ethanolic and aqueous extracts of Tecoma stans linn leaves by using behavioural animal models of anxiety. The major finding of present investigation propose the anxiolytic activity on elevated plus maze test, light/dark transition test in mice and hole board test, social interaction test in rats.

           

            The elevated plus maze is currently one of the most widely used model of animal anxiety and it’s validated and use in rats and mice¹²⁷. 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 arm¹²². 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 GABAA receptor complex, justifying the use of diazepam as a positive control in this study¹²⁴, 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 Tecoma stans linn leaves had not similar effects on these parameters.  The EE2 extract has significantly increased time spent in open arm and decrease time spent in close arm as compare to control, whereas the aqueous extract dose AE2 shows decrease percentage of entries and  time spent in close arm and increase percentage of time spent in open arm and entry in open arm. The aqueous and ethanolic extracts had increased the percentage time spent in open arm and entry in to open arm and  decreased percentage time spent in closed arm and entries in closed arm.

            It can be suggested that ethanolic extract (800 mg/kg)  and aqueous extract (800 mg/kg)  may have the anxiolytic effects similar to the standard drug as result animal spent more time in open arm and less time in closed arm. Ethanolic extract (400 mg/kg) and aqueous extract (400 mg/kg) also did not showed significant anxiolytic effect. There fore behavioural alterations are induced by the higher dose of aqueous and ethanolic (800 mg/kg) extract.

 

            The hole-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 behavior 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 behavior¹⁶⁸. In present study, aqueous and ethanolic extract of (800mg/kg) had significantly increased head dip latency; head dip count, no of assisted rearing,  and  locomotion. Diazepam a putative anxiolytic agent increased the number of head dip latency, head dip count, rearing,  locomotory activity as compare to control group. Therefore the increased number head dip count; head dip latency, rearing,  is not only representation of hyper-reactivity but also reflection of anxiolytic effects.

 

            Light/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 behavior of rodents in response to mild stressors that is novel environment and light¹⁶⁴.

            Drugs induced increase in behavior 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 activity¹⁶⁵. In this study, the time spent in light and dark area is an indices of anxiety. The ethanolic extract (400mg/kg) and aqueous extract (400mg/kg) had also showed increase in the time spent in light area, decrease in the time spent in dark area but now so significantly. The aqueous extract (800mg/kg) had significantly increased the time spent in light area, entry in light, dark chamber and decreased the time spent in dark area and ethanolic extract (800mg/kg) increased the time spent in light area and decreased the time spent in dark area similar to standard drug, suggesting that anxiolytic activity of Tecoma stan linn leaves extract as compare to control group.

 

              The OFT is used to evaluate the animal’s emotional state. The open field model examines anxiety related behavior characterized by the normal aversion of the animal to an open, brightly lit area. Thus, animals removed from their acclimatized cage and placed in environment express anxiety and fear, by showing alteration in all or some parameters.

 

            Anxiolytic treatments reduce such fearful behavior of animals in open field¹⁶⁹    In present study, Diazepam a putative anxiolytic agent significantly increased the locomotion,  no. of assisted rearing, entries in the central square and time spent in central square as compared to control group.  The aqueous and ethanolic extract  (800mg/kg) had  increased the locomotion,  no. of assisted rearing, entries in the central square and time spent in central square as compared to control group.