The Kingdom of Saudi Arabia covers 2,250,000 km2, most of which is lowland plain. However, there are also extensive mountain chains and associated valleys. The Sarawat Mountains (Fig. 1), which range in altitude between 800 and 3,000 metres above sea level, stretch for more than 1,000 km, and are the
dominant ones. These mountains have diverse climates and receive adequate rainfall in summer, winter and early spring to support the growth and

ABSTRACT. The bioactive compounds proceraside A, frugoside and calotropin, which were extracted from the root bark of Calotropis procera (Aiton) W.T. Aiton (family Asclepiadaceae), were recently reported to inhibit the growth of inhibition against various human cancer cell lines in vitro. However, their modes of action have not been clearly defined. Therefore, we attempted an in silico approach to gain insights into their binding modes against the following selected molecular targets: CDK-2, CDK-6, topoisomerase I, BCL-2, VEGFR-2, telomere: G-quadruplex, and topoisomerase II.