Isomahanimbine, a carbazole alkaloid found in M. koenigii leaves, has shown many health benefits. Generally, isomahanimbine was extracted and isolated by  conventional methods using different organic solvents by column chromatography followed by TLC or HPLC. These conventional extraction and isolation methods,  using non-eco-friendly organic solvents, are often tedious and time-consuming and require multiple steps, which might reduce the yield. Therefore, an efficient, rapid,  and environment-friendly method is needed. Here, isomahanimbine was extracted from M. koenigii leaves using microwave-assisted green extraction using green  solvent-ethanol. Further, a rapid eco-friendly two-step technique has been developed to isolate isomahanimbine from M. koenigii leaves without standard compounds  with fewer steps by RP-preparative-HPLC using green solvent, water, and methanol. The present method yields 25-45 mg of isomahanimbine and 110-160 mg of  mahanimbine from 1.4-2.0 kg leaves of Murraya koenigii, simultaneously. It was also found that isomahanimbine was shown to have anti-cancer activity, particularly  against human lung cancer.