**4. Cytotoxic activity of euphorbiaceae**

Numerous investigations indicated that the *C. oblongifolius* shows cytotoxic properties. Neocrotocembranal obtained from the stem bark of *C. oblongifolius* displayed cytotoxic activity toward P-388 cells with an IC50 value of 6.48 μg/mL [13]. *C. oblongifolius* contain methyl 15,16-epoxy-3,13(16),14-ent-clerodatrien-18,19-olide-17-carboxylate, dimethyl 15,16-epoxy-12-oxo-3,13(16),14-ent-clerodatrien-17,18-dicarboxylate, nasimaluns A and B, levatin, (−)-hardwickiic acid, 15-hydroxy-cis-ent-cleroda-3,13- (E)-diene, and patchoulenone. These diterpenoids exhibited mild cytotoxic activity against HUCCA-1 (human cholangiocarcinoma cancer cells), KB (human epidermoid carcinoma of the mouth), HeLa (cervical adenocarcinoma cells), MDA-MB231 (human breast cells), and T47D (human mammary adenocarcinoma cells) cell lines with the IC50 values ranging from 10 to 50 μg/mL [14]. Additionally, the in vitro cytotoxic activity of 2,3-dihydroxy-labda-8(17),12(E),14-triene has been demonstrated non-specific moderate activities in KATO-3 (IC50 value 2.2 μg/mL), SW620 (IC50 value 2.7 μg/ mL), BT474 (IC50 value 4.6 μg/mL), HEP-G2 (IC50 value 3.7 μg/mL), and CHAGO (IC50 value 3.3 μg/mL) [15]. Moreover, crotohalimaneic acid, crotohalimonetic acid, and 12-benzouloxy crotohalimaneic acid from *C. oblongifolius* were examined for their cytotoxic activity against human breast ductol carcinoma (BT474), lung carcinoma (CHAGO), human liver hepatoblastoma (HEP-G2), human gastric carcinoma (KATO-3), and human colon adenocarcinoma (SW620). The latter compound was inactive and the remaining two compounds displayed non-specific strong cytotoxic activity, and the IC50 values for crotohalimaneic acid were 7.5, 0.1, 0.2, 0.4, 0.2, and for crotohalimonetic acid were 0.1, 0.1, 5.2, 8.2, 0.1 μg/mL, respectively [17]. In another study, novel furanocembranoids, found from the stem bark of *C. oblongifolius*, have been shown broad cytotoxic effects on BT474, CHAGO, Hep-G2, KATO-3, and SW-620 [18]. Besides, croblongifolin obtained from *C. oblongifolius* was reported to have high cytotoxic activities against human hepatocarcinoma (HEP-G2) (IC50 0.35 μM), breast carcinoma (BT474) (IC50 0.12 μM), colon carcinoma (SW620) (IC50 0.47 μM), lung carcinoma (CHAGO) (IC50 0.24 μM), and gastric carcinoma (KATO 3)
