A research had been conducted to isolated, to identify and to test biological activity of active isolates from n-hexane extracts of casturi (Mangifera casturi Konsterm.) fruit. The research aims at isolating active isolates from n-hexane fractions and testing for antioxidant and immunomodulatory activities. n-hexane fractions were isolated using column chromatographic method by using n-hexane-ethylacetate as eluents with eluent gradient (20:1; 15:1; 10:1; 8:2; 7:3; 6:4 and 5:5) v/v. The isolated compounds (purified isolates) were white crystals identified as terpenoid compound. Identification of chemical structures found a compound, namely, 1-isopropenyl-3a, 5a, 5b, 8, 8, 11a-hexamethyl-eicosahydro-cyclo penta [α]chrysen-9-ol (lupeol). The isolated compound was tested for antioxidant activity using DPPH (1,1-diphenyl -2-picrylhydrazyl) method with an IC50 value of 14384.71-lower than that of quercetin control (IC50 = 2.962). The finding shows that the isolate is not a potent compound against DPPH free radical inhibition. In vitro immunomodulatory activity test was conducted for the isolated compound. The isolates were given at dosages of 6.25, 12.5, 25, 50 and 100 μg. The test revealed increasing macrophage activity against latex bead phagocytosis. The highest phagocytosis activity and capacity were found at a dosage of 100 μg, namely, latex-bead consuming macrophage by 26% and macrophage-eaten latex bead by 32% (significant, compared to the negative control, namely, latex-bead eating macrophage by 13% and macrophage-eaten latex bead by 15%).