Murrayakoenigii and Glycosmispentaphylla are rich sources of carbazole alkaloids. Some of these carbazole alkaloids have shown potent biological activities. In the present work, three different derivatives of the naturally occurring carbazole alkaloid murrayanine 7 were prepared in search of bioactive organic substances. One of the carbazole alkaloids among these have shown potent anti-asthma activitycomparable to the known PDE4 inhibitor, rolipram. This paper is on isolation, characterisation, derivative preparation and determination of biological activities of some carbazole alkaloids obtained from these two plants.