**2.9 2 β,3β,16α,20(***R***),25-Pentahydroxy-22-oxocucurbita-5-en (RPO) (9')**

 This compound is a cucurbitacin isolated from *Cayaponia racemosa* Cong. The anticancer activity of RPO was evaluated with in vitro and in vivo models. Cucurbitacin (**9′**) reduced the number of viable HL-60 leukemia cells; however, there was no change in the number of nonviable cells at 5 μg/mL. This compound had no effect on normal proliferating lymphocytes at the concentrations tested (IC50 > 25 μg/mL). Morphological analysis of RPO-treated cells showed typical apoptotic features, such as heavy deposition of granules in the cytoplasm (eosinophilia), DNA fragmentation and irregularities in the plasma membrane, and intense vacuolization and disruption of the plasma membrane. Acridine orange/ethidium bromide staining confirmed these findings, revealing an increased number of apoptotic cells. In the sarcoma 180 tumor model, compound (**9′**) showed 52 or 62% antitumor activity when administered alone (25 mg/kg/day) or in association with the chemotherapeutic agent 5-FU (10 + 10 mg/kg/day), respectively. Moreover, treatment with compound (**9′**) either alone or in combination with 5-FU caused an increase in spleen weight and morphological alterations related to immunostimulatory properties [27].

#### **2.10 Cucurbitaglycosides A (10′) and B (11′)**

Phytochemical investigation of the fruits of *Cucurbita pepo* cv. dayangua led to the isolation of cucurbitaglycosides A (**10′**) and B (**11′**). This was the first report of *Cytotoxic and Antitumoral Activities of Compounds Isolated from Cucurbitaceae Plants DOI: http://dx.doi.org/10.5772/intechopen.82213* 

**Figure 2.**  *2β,3β,20(S),26,27-Pentahydroxy-16α,23(S)-epoxycucurbita-5,24-dien-11-one.* 

 cucurbitane triterpenoids with a purine unit. Cucurbitaglycosides A and B showed cytotoxic activity against the human epithelial carcinoma cell line HeLa with IC50 values of 17.2 and 28.4 μg/mL, respectively [28].
