Isolation, Characterization and Evaluation of Anti-Alzheimer Activity on the Aerial Parts of Oxystelma Esculentum R.Br.

Vanmugilan, S (2021) Isolation, Characterization and Evaluation of Anti-Alzheimer Activity on the Aerial Parts of Oxystelma Esculentum R.Br. Masters thesis, College of Pharmacy, Madras Medical College, Chennai.


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Oxystelma esculentum R.BR.aerial parts was selected for the present research work to investigate the anti-alzheimer activity. First the aerial parts of O.esculentum was sequentially extracted by hot continous percolation method by using solvents such as Hexane, Chloroform, Ethyl acetate and Ethanol. All the extracts were screened for preliminary phytochemical screening to determine the secondary metabolites present in the extract. It was observed that the ethanol extract possess maximam phytoconstituents compared to other extracts, containing glycosides, flavonoids, terpenoids, alkaloids, phytosterol and phenolic compounds. These active constituents possess numerous pharmacological activities. INVITRO ACETYLCHOLINESTERASE INHIBITION ASSAY: All the extracts were investigated for in vitro acetylcholinesterase inhibition assay. It was observed that ethanol extract exhibits good acetylcholinesterase inhibition compared with other extracts with an IC50 value of 38.54. The polyphenolic compounds such as flavonoids, terpenoids, glycosides have inhibitory capacity against acetylcholinesterase similar to that of currently prescribed synthetic drugs. Hence ethanol extract was considered as an active extract and subjected for in vivo anti-alzheimer activity and for isolation of compounds by column chromatography. ACUTE TOXICITY STUDY: The ethanol extract was found to be non toxic and safe upto the dose of 2000mg/kg body weight. The LD50 value is expected to increase the dose level above 2000mg/kg. From this 1/10 th(200mg/kg) and 1/5th(400mg/kg) was selected for in vivo studies. In vivo anti Alzheimer activity of ethanol extract of O.esculentum. In vivo anti Alzheimer activity was investigated by evaluating the ethanol extract against Y Maze, Open feild and Traction test method.The treatment of 200mg/kg and 400mg/kg of ethanol extract of O.esculentum showed a significant increase in (p<0.001) spantaneous alterations and improve the memory and learning ability in mice. In open feild method, ethanol extract of O.esculentum at 200mg/kg and 400mg/kg exhibited a significant increasing effect on number of crossings and number of rearings compared to scopolamine group. The high dose of 400mg/kg of extract exhibited a better exploratory behaviour in mice in number of crossings. In traction, the administration of O.esculentum has shown a significant effect on enhancing the motor co-ordination and balancing ability in mice. At 400mg/kg of ethanol extract of O.esculentum exhibits significant (p<0.001) spending more time balancing ability compared to scopolamine induced group. Biochemical estimation The administration of scopolamine induces oxidative damage in animals MDA level increases significantly in the mice of group rearing scopolamine. The level of MDA significantly decrease in the group of animal that received the treatments with the dose of ethanol extract of O.esculentum. Treatment of 400mg/kg of ethanol extract of O.esculentum significantly increase the glutathione level p<0.001 Administration of 400mg/kg of ethanol extract significantly increase the level of catalase. Isolation of compound from active extract by Column chromatography. The ethanol extract shows promising effect in both in vitro and in vivo anti Alzheimer activity. Hence ethanol extract was subjected to column chromatography isolation.The ethanol extract was eluted with various solvents by gradient elution technique. The yellow colour band was eluted and collected from the fraction 85-88 in the solvent composition chloroform:methanol. The collected yellow fractions showed a single spot in TLC, UV (254nm,366nm), and in iodine vapour. Hence the fractions were mixed together and designated as V1. The isolated compounds was characterized by UV, FT-IR, 1H-NMR and LC-MS. From the characterization report the isolated compound was determined as Kanokoside D, which is a Iridoid glycoside. Acetylcholinesterase inhibition of Kanokoside D The isolated Kanokoside D was investigated for acetlcholinesterase inhibition assay. It was observed that Kanokoside D has good AchE inhibition with an IC50 value of 135.54 compared with the standard Donepezil has a greater inhibition of 85.89. In silico molecular property and docking study of Kanokoside D The molecular properties of Kanokoside D were calculated by using In silico Molinspiration Cheminformatics tool showed that the Kanokoside D compound slightly violating the Lipinski’s rule of 5 (3 violations). The compound Kanokoside D was docked with two targets Human acetylcholinesterase and β-secretase. The ligand (Kanokoside D) showed a better binding energy -4.38 with that of standard Rivastigmine having -5.82 with the target acetylcholinesterase. The ligand form hydrogen bond interaction with Asparagine 230, leucine 305 and glutamic acid 306. The molecular docking study of Kanokoside D against β-secretase shows a better binding energy of 6.82 k cal than the standard Rivastigmine having -4.67 k cal. The ligand showing hydrogen bond interactions with Alanine 157, Valine 361, histidine 360, cysteine 359 and valine 170. It clearly indicates that Kanokoside D shows potential role in AD. CONCLUSION: Ethanolic extract of O.esculentum shows promising role in anti-alzheimer activity by evaluating against scopolamine induced amnesia. The phytochemical constituents in the ethanol extract may be responsible for the decrease in neurotoxcity in mice.The Kanokoside D an iridoid glycoside, first isolated from the plant and have a role in inhibition of neurotoxcity and improvement of memory in mice.

Item Type: Thesis (Masters)
Additional Information: 261915709
Uncontrolled Keywords: Isolation, Characterization, Evaluation, Anti-Alzheimer Activity, Aerial Parts, Oxystelma Esculentum R.Br.
Subjects: PHARMACY > Pharmaceutical Chemistry
Depositing User: Subramani R
Date Deposited: 02 Nov 2022 17:55
Last Modified: 03 Nov 2022 14:37

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