The incidence of prostate cancer malignancy along with other cancer types is increasing worldwide, resulting in high mortality rate due to lack of effective medications. Moringa oleifera has been used for the treatment of communicable and non-communicable ailments across tropical countries, yet, little has been documented regarding its effect on prostate cancer. We evaluated the acute toxicity and apoptosis inducing effect of glucomoringin-isothiocyanate rich soluble extracts (GMG-ITC-RSE) from M. oleifera in vivo and in vitro, respectively. Glucomoringin was isolated, identified, and characterized using fundamental analytical chemistry tools where Sprague-Dawley (SD) rats, murine fibroblast (3T3), and human prostate adenocarcinoma cells (PC-3) were used for acute toxicity and bioassays experiments. GMG-ITC-RSE did not instigate adverse toxic reactions to the animals even at high doses (2000 mg/kg body weight) and affected none of the vital organs in the rats. The extract exhibited high levels of safety in 3T3 cells, where more than 90% of the cells appeared viable when treated with the extract in a time-dependent manner even at high dose (250 µg/mL). GMG-ITC-RSE significantly triggered morphological aberrations distinctive to apoptosis observed under microscope. These findings obviously revealed the putative safety of GMG-ITC-RSE in vivo and in vitro, in addition to its anti-proliferative effect on PC-3 cells.