N-Methylneolitsine as a new and potent acetylcholinesterase inhibitor of Cissampelos pareira Linn. aerial parts: bioassay-guided isolation and quantitative densitometric analysis.

The rising geriatric population is expected to increase the demand for drugs treating neurodegenerative diseases. The present work is aimed to discover acetylcholinesterase (AChE) inhibitors from Cissampelos pareira Linn. aerial parts (Family: Menispermaceae). Bioassay-guided isolation, AChE inhibition study and estimation of the therapeutic marker in different parts of raw herbs were conducted. The structure of the compound (1) was elucidated as N-methylneolitsine by using NMR (1D and 2D) and ESI-MS/MS spectral data, which is a new natural analogue of neolitsine. It showed good AChE inhibition with an IC50 value of 12.32 µg/mL. It was densitometrically estimated to be 0.074 - 0.33% in aerial parts of C. pareira, collected from various locations. The alkaloid reported here could be potentially useful for the treatment of various neurodegenerative diseases and the aerial part of C. pareira could be used as a promising ingredient for various preparations treating neurodegenerative diseases.

Estimation of Levodopa in the Unani Drug Mucuna pruriens Bak. and Its Marketed Formulation by High-Performance Thin-Layer Chromatographic Technique.

BACKGROUND: Mucuna pruriens Bak. Syn. Mucuna prurita Hook. seed is the rich source of levodopa (L-dopa) and has been used in traditional medicines to treat diseases resembling Parkinson's disease. OBJECTIVE: In the present study, a new HPTLC method was developed and validated for estimation of L-dopa from M. pruriens (black- and white-colored seeds) collected from two different locations in India. METHOD: TLC aluminum plates precoated with silica gel were used as the stationary phase. The plates were developed to a distance of 60 mm at a temperature of 22 ± 4°C in a twin glass chamber saturated with ethyl acetate-methanol-formic acid-water (15+3+3+4.5, v/v/v/v), as the mobile phase. RESULTS: The Rf value of L-dopa was found to be 0.45. L-dopa was quantified at 282 nm, the wavelength of maximum absorbance by a densitometric scanner. The TLC plate was derivatized by ninhydrin reagent and photodocumented. L-dopa showed a good linearity in the concentration range 400-1000 ng/spot. The linear regression analysis of calibration plot showed good linear relationship between peak area and peak height (r2 = 0.997). CONCLUSIONS: The method was validated for precision, repeatability, and accuracy. Recovery was determined by spiking L-dopa with samples and was found to be 96.10%. HIGHLIGHTS: L-dopa was found to be present at concentration 3.02-4.72% in samples and its formulation.