Pharmacologically Active Principles in Extracts of Plants Suitable for Nepalese Horticulture

Rhazya stricta Decaisne (Apocynaceae) and Paris polyphylla Smith (Liliaceae) have been investigated as possible sources of medicinal chemicals. They have been presented as separate projects.

Rhazya stricta Decaisne, an indole alkaloid bearing plant has been examined for its pharmacological activity. The chromatographic separation of the crude extract of the plant material led into the isolation of six alkaloids which are examined pharmacologically. The identification of these compounds is done by spectroscopic methods including infrared, mass spectrum, 1H and 13C - nuclear magnetic resonance and chromatographic techniques. These alkaloids were converted to quaternary ammonium compounds and their ganglion blocking potencies are tested. The study has been extended to the pharmacological examination of the quaternary compounds of indole alkaloids of other origins. Significant ganglion blocking and neuromuscular blocking activity has been found in some of the quaternised alkaloids, Introductory mass spectrometric study has been made of the indole alkaloids which had been done to a very limited extent before the present work.

Paris polyphylla Smith has been examined for central nervous system activity. Chromatographic techniques have led to the isolation of two saponins showing central nervous system depressant activity. Preliminary characterisation of these saponins has been achieved.

Paris polyphylla has also been examined for the Possibility of being a source of diosgenin. Analysis of plant materials from different localities at different stages of its growth and various organs of the plant material has been examined for diosgenin content. The analysis has been carried out by using different chromatographic techniques. Leaves were found to contain high yield of diosgenin. Presence of sucrose in high proportion was also observed in the roots of P. polyphylla.