Alzheimer's is an irreversible and dynamic neurodegenerative ailment which associated with the age and characterized by serious loss of memory, personality changes, uncommon behaviour and decrease in intellectual capacity. Till now no countermeasure available for Alzheimer's, however symptomatic treatment may enhance memory and other issues related to this disease. Products from natural resources such as medicinal plants have been utilized for the treatment of various memory disorders like amnesia, dementia, Alzheimer's, Parkinson since long time. Various studies depicted the utilization of therapeutic plants for treatment of Alzheimer's. In spite of that exact mode of their action is yet indistinct. Phytochemical investigations of various plant parts have demonstrated presence of numerous bioactive compounds, such as polyphenols, tannins, flavonoids, triterpenes, alkaloids and sterols. These compounds demonstrate an extensive variety of pharmacological activities which includes anticholinesterase, antiinflammatory, antiamyloidogenic, hypolipidemic, and antioxidant effects. This review provides the description of different medicinal plants against Alzheimer's disease.

Centella asiatica commonly known by names like gotu kola, Mandukaparni or Indian pennywort is a small herbaceous perennial medicinal plant belonging to Apiaceae family. Its active metabolites are triterpenoids which includes asiaticoside, asiatic acid, madecassoside, madecassic acid which has wide range of pharmaceutical activities like wound healing, memory enhancer, treatment of skin diseases etc. The present work is aimed to perform phytochemical analysis and estimation of antioxidant activity by DPPH assay. The antioxidant activity by DPPH assay showed maximum IC 50 value in CSC extract than shoot and callus extracts. The quantitative estimation of total phenolic, flavanoids and tannins indicates highest phytochemicals in SC when compared to CC and CSC.

Due to the presence of several bioactive compounds, Centella asiatica (L.) is used in traditional medicine for the treatment of various ailments. This usage of plant and its products created a huge demand which required an alternative method of its commercial production so that the loss of natural plant and its genetic pool can be prevented. A different investigation using biotechnological methods provided a wealth of information to enhance the biomass as well as different bioactive compounds. In the present study, we focused and reported the effect of different nitrogen sources on shoot proliferation of Centella asiatica. Effect of malt extract as plant elicitor on asiaticoside production as well as fatty acid methyl ester (FAME) profile was also worked out. Four different nitrogen sources i.e., NH 4 NO 3 (1.65 g/l), KNO 3 (0.8 g/l), NaNO 3 (1.65 g/l), Ca(NO 3 ) 2 (0.825 g/l) on five different accessions of Centella asiatica were tested and accession number 347492 (14.66 ± 2.4) provided maximum shoot proliferation with ammonium nitrate. RP-HPLC analysis of accession number 347492 revealed that malt extract as plant extract enhanced 6 times asiaticoside in comparison to standard conditions. GC-MS analysis of five different accessions of Centella asiatica concluded that this plant is rich in the content of Pentadecanoic acid, 9, 12 Octadecadienoic acid (Linoleic acid) and 9, 12, 15 Octadecatrienoic acid (Linolenic acid). Most potential fatty acid methyl esters containing plant accession number is 281374.

The objective of the study was to assess the effect of three plant tissue culture media (MS, Gamborg's B5 and Nitsch) on the growth of five accessions of Centella asiatica using nodal explant. All the three media supplemented with 1 mg/l BAP resulted in increased growth. Amongst the three Medias, MS media resulted in the highest shoot multiplication in all the five accessions after eight weeks of the incubation period. The highest number of shoots and maximum shoot length were obtained in accession number 342109 (19.6±0.57 shoot number, 4.9±0.53 shoot length) grown in MS media supplemented with 1 mg/l BAP. Estimation of stigmasterol, an important phytosterol present in the leaves (main part for synthesis) was done by using gas chromatography and the highest amount of stigmasterol was obtained in accession number 342109 i.e. 0.0228µg/mg of leaves.

Plumbago zeylanica is a pharmaceutically important plant which belongs to Plumbaginaceae family. It possesses wide range of pharmacological activities which includes antibacterial central nervous system stimulatory activity, anti-fungal, anti-inflammatory, anti-hyperglycemic, anti-cancer and anti-atherosclerotic activity. Fatty acid methyl ester analysis reveals the presence of various fatty acids in the plant. The present study deals with Fatty acid methyl ester profile of five different accession of Plumbago zeylanica. Results reveal that these accessions are rich in Octadecadienoic acid (8-22%), Octadecatrienoic acid (7-24%) and Pentadecanoic acid (11-22%) fatty acids. Accession number 421418 is contains the highest amount of Pentadecanoic acid and 9,12,15 Octadecatrienoic acid. Accession number 439212 contains highest amount of Hexadecanoic acid. Highest amount of 9,12 Octadecadienoic acid was present in accession number 524441.