Nootropic and Free Radical Scavenging Activity of Plumbago zeylanica Linn. By Different In-Vivo & In-Vitro Methods

Abstract

AIM- The aim of the present investigation is to evaluate Plumbago zeylanica L. (Plumbaginaceae) for evaluation of memory enhancing activity. MATERIAL & METHODS- All the plant materials were dried under shade and subjected to coarse powder for extraction process. Accurately weighed quantity of roots of Plumbago zeylanica Linn. extracted using petroleum ether, chloroform, methanol, butanol and finally water by soxhlet apparatus for 72 h. Qualitative chemical tests of chloroform, methanol, butanol and water extracts were subjected to various chemical tests to detect various Phytoconstituents. Briefly, 6.0 mg ß-carotene was dissolved in 10 ml of chloroform, and then 1 ml of solution pipette to glass filled of 20 mg linoleic acid. 5 ml of mixture then pipette to reaction tube filled of extract in a range of concentration, mixed homogenously. Briefly, 1 mL of 0.3 mM of DPPH solution was added to 1 mL each of the test solutions, and was incubated in the dark at room temperature for 30 min. Escape latency (EL) was recorded 120 min after drug administration from 11th day to 14th day. On 15th day, time spent in target quadrant (TSTQ) was noted 120 min after the drug administration. In case of animals administered with physostigmine, EL and TSTQ was noted after 30 min of drug administration. 0.4 ml of brain homogenate was added into a test tube containing 2.6 ml of phosphate buffer. 5,5-dithiobis-2-nitrobenzoic acid reagent (0.1 ml) was added to the above mixture and absorbance was noted at 412 nm. RESULTS- The preliminary phytochemical analysis revealed that different active constituent present in different extracts such as carbohydrates, proteins, amino acids, fat, oils, steroids, terpenoids, glycosides, alkaloids, tannins and other phenolics compounds. Vitamin E as standard was used in this assay and 84% inhibition was found to be at 30 minutes. Chloroform extract also showed 70% inhibition at 30 minutes which was reduced to 45% at the time of 120 minutes.  Hydroxyl radical scavenging ability calculated as IC₅₀ reveals that chloroform; methanol, butanol and water extracts have IC₅₀ values of 47 μg/mL, 100μg/mL, 200 μg/mL and 150μg/mL, respectively. Among all the extracts, chloroform extract showed a highly significant effect on EL and TSTQ. Chloroform extracts significantly decreased (P<0.001) EL and significantly increased TSTQ as compared to vehicle treated control. CONCLUSION- The deterioration and dysfunction of cortical cholinergic neurons is closely associated with cognitive deficits of Alzheimer’s disease.

Keywords: Alzheimer’s disease, Vitamin E, DPPH solution, Plumbago zeylanica Linn., Plumbaginaceae, EL and TSTQ