Background: Abrus precatorius Linn. (Kunch in Bengali) is widely spread in tropical and sub-tropical regions. It is a typical plant species which is well-known simultaneously as folk medicine and for its toxicity. Objective: Phytoceutical investigation of the white variety seeds of Abrus precatorius Linn. Methods: Traditional extraction, separation, isolation, and purification processes were followed. The structure was elucidated by various spectral analyses and the solid-state structure of this indolealkaloid was determined by X-ray crystallographic analysis. Docking interactions of L-abrine had been studied against ten major proteins, responsible for various types of cancers. In silico studies were done by Schrödinger Maestro, AutoDock4, PyMOL and AutoDock Vina. The protein structures were downloaded from Protein Data Bank. Sulforhodamine B (SRB) colorimetric assay was used for in vitro anticancer evaluation against four human cancer cell lines. Results: An indole-containing unusual amino acid alkaloid had been isolated from the white variety seeds of Abrus precatorius Linn. In silico docking studies demonstrated significant antiproliferative activity against four human cancer cell lines. Conclusion: The solid-state zwitterion structure of the indole-containing alkaloid (α-methylamino- β-indolepropionic acid, L-abrine) has been confirmed for the first time by X-ray crystallography. Highly promising in silico and in vitro results indicate that L-abrine may find its space in future anticancer drug discovery research.

World Health Organization (WHO) identified twenty tropical disease categories as neglected tropical diseases (NTDs)1. Chagas’ disease (also known as American trypanosomiasis) and leishmaniasis are two major classes of NTDs. The total number of mortality, morbidity, and disability attributed each year due to these two categories of diseases in magnitudes is much higher than the so-called elite diseases like cancer, diabetes, AIDS, cardiovascular and neurodegenerative diseases. Impoverished communities around the world are the major victim of NTDs. The development of new and novel drugs in the battle against Chagas’ disease and leishmaniasis is highly anticipated. An easy and straightforward on-water green access to synthesize benzopyrazines is reported. This ultrasound-assisted procedure does not require any catalyst/support/additive/hazardous solvents and maintains a high atom economy. A series of eleven benzopyrazines has been synthesized, and most of the synthesized compounds possess the drug-likeness following Lipinski’s “Rule of 5”. Benzopyrazines 3 and 4 demonstrated moderate leishmanicidal activity against L. mexicana (M378) strain. The selective lead compound 1 showed good leishmanicidal, and trypanocidal activities (in vitro) against both L. mexicana (M378) and T. cruzi (NINOA) strains compared to the standard controls. The in vitro trypanocidal and leishmanicidal activities of the lead compound 1 have been validated by molecular docking studies against four biomolecular drug targets viz. T. cruzi histidyl-tRNA synthetase, T. cruzi trans-sialidase, leishmanial rRNA A-site, and leishmania major N-myristoyl transferase.