Unprecedented Insights on Chemical and Biological Significance of Euphorbia cactus Growing in Saudi Arabia

Abstract

Euphorbia cactus Ehrenb ex Boiss. is a plant species reported from central Africa and the southern Arabian Peninsula, belonging to the family of Euphorbiaceae. The plant has ethnobotanical values and is well-known for its milky latex, which has been turned into medicine to treat various ailments. To the best of our knowledge, there have been no literature reports available on phytochemical constituents and antiproliferative mechanism of E. cactus. In the current study, the phytochemical investigation of E. cactus methanolic extract (ECME) resulted in the isolation and characterization of four secondary metabolites, which are reported for the first time from this plant species. In addition, the results of 1,1-diphenyl-2-picrylhydrazyl (DPPH•) and ferrous ion chelating (FIC) assays expressed maximum antioxidant activity by ECME and the isolated phytochemicals. Furthermore, ECME exerted a promising antiproliferative effect against different cancer cell lines, and the A549 lung cancer cells were the most sensitive with an IC50 value of 20 µg/mL. The antiproliferative action of ECME in A549 cells was associated with cell accumulation in the G2/M phase and an increase in early and late apoptosis. In addition, RT-PCR and western blot analysis revealed that ECME decreased the anti-apoptotic (Bcl-2) expression, while the expression of pro-apoptotic (Bax) and caspase-3 were increased. This study provides the first insight into the phytochemical constituents and the antiproliferative mechanism of ECME, implying that it could be exploited as a promising natural source for developing new cancer therapies. Further preclinical research is warranted to support the current results.

Revisiting the Flora of Saudi Arabia: Phytochemical and Biological Investigation of the Endangered Plant Species Euphorbia saudiarabica

“…This suggests that apoptosis was one of the cell-death modes caused by both fractions. This finding is consistent with other reports demonstrating that the anticancer effects of several Euphorbia species on different cancer-cell lines were due to their apoptosis-inducing activity [10,13,38,43]. To confirm the observed apoptotic effects of both fractions, RT-PCR was used to evaluate the levels of the Bcl-2-family genes that are involved in apoptosis.…”

“…This characteristic is linked with the mechanism of the wellknown anticancer drug, paclitaxel [37]. The cell-cycle-pattern arrest observed in the G2/M phase in this study is similar to those in several other studies of the same Euphorbia species, including E. hirta [13], E. erythradenia [38], E. lunulata [39] and E. cactus [10], with different cancer cells. Standard cancer treatments are intended to initiate apoptotic cell death, which is a fundamental process in preventing cancer-cell growth [40][41][42]}.…”

“…Several studies have shown the beneficial effects of natural phytochemicals on the treatment of various illnesses, including cancer [26]. In this study, as part of our continuing search for the cytotoxic properties of Euphorbia species grown in Saudi Arabia [10], we report, for the first time, the anticancer activity of E. saudiarabica against a panel of human…”

“…Cell viability was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, as previously described [10]. Different cancer cells, including lung (A549), colon (LoVo) and breast (MCF-7) cancer cells, as well as normal HUVEC cells, were employed in this study.…”

“…Euphorbiaceae is a family of flowering plants with a rich history of ethnomedicinal use, in which Euphorbia is considered the third largest genus. Plants from this genus have traditionally been used to treat skin disease, venomous insect bites, abdominal pain, abdominal distention, trichiasis, and paralysis [10]. These therapeutic properties of Euphorbia species could be attributed to the presence of numerous secondary metabolites, such as triterpenes, diterpenes and flavonoids, which exhibit a wide range of biological activities.…”