Euphorbia species latex: A comprehensive review on phytochemistry and biological activities

Abstract

The genus Euphorbia includes about 2,000 species commonly widespread in both temperate and tropical zones that contain poisonous milky juice fluid or latex. Many species have been used in traditional and complementary medicine for the treatment of various health issues such as dropsy, paralysis, deafness, wounds, warts on the skin, and amaurosis. The medicinal applications of these species have been attributed to the presence of various compounds, and most studies on Euphorbia species have focused on their latex. In this review, we summarize the current state of knowledge on chemical composition and biological activities of the latex from various species of the genus Euphorbia. Our aim was to explore the applications of latex extracts in the medical field and to evaluate their ethnopharmacological potential. The databases employed for data collection, are obtained through Web of Science, PubMed, Google Scholar, Science Direct and Scopus, from 1983 to 2022. The bibliographic data indicate that terpenoids are the most common secondary metabolites in the latex. Furthermore, the latex has interesting biological properties and pharmacological functions, including antibacterial, antioxidant, free radical scavenger, cytotoxic, tumor, anti-inflammatory, healing, hemostatic, anti-angiogenic, insecticidal, genotoxic, and mutagenic activities. However, the role of other components in the latex, such as phenolic compounds, alkaloids, saponins, and flavonoids, remains unknown, which limits the application of the latex. Future studies are required to optimize the therapeutic use of latex extracts.

Keywords: Euphorbia species; Euphorbiaceae; biological applications; chemical constituents; latex.

FIGURE 1

Structure of chemicals compound 1, 7-10, 26-29 (Giner et al., 2000; Daoubi et al., 2007; de Souza et al., 2019).

FIGURE 2

Structure of chemicals compounds (30-35, 46-53) and (55) (Urones et al., 1988; Ilyas et al., 1998; Mallavadhani et al., 2004; Hua et al., 2015; Deng et al., 2021).

FIGURE 3

Structure of chemicals compounds (56-57, 62-68) (Urones et al., 1988; Gewali et al., 1990).

FIGURE 4

Structure of chemicals compounds (70-74; 76; 78; 81) and (84-94) (Esposito et al., 2016; Li et al., 2022).

FIGURE 5

Structure of chemicals compounds (95-98) and (108-109) (Marco et al., 1999; Esposito et al., 2016).

FIGURE 6

Structure of chemicals compounds (110-124) (Krstić et al., 2018).

FIGURE 7

Content of compounds 30 and 33 in the different parts of E. fischeriana (***p < 0.001, student’s test) (Deng et al., 2021).

FIGURE 8

The molecular weight of the lipase from E. peplus latex (EPLL) obtained by Sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) (Lazreg Aref et al., 2014).

FIGURE 9

The ¹ H NMR spectrum of rubber extracted from E. characias latex. Peaks at 5.31, 2.17, and 1.73 ppm are attributed to the olefinic, methylene and methyl protons, respectively, of the cis-1,4-polyisoprene (Spanò et al., 2012). * and ** indicates 1 H NMR residual signal of cyclohexane (1.43 ppm) and methyl-protons of a trans-isoprene unit (1.62 ppm), respectively.

FIGURE 10

The ¹³C NMR spectrum of rubber extracted from E. characias latex. The peaks at 135.2,125, 32.2, 26.4, and 23.4 arises from the two ethylenic, two methylenic, and the methyl carbon atoms of the cis-1,4-polyisoprene, respectively (Spanò et al., 2012).

FIGURE 11

Molecular weight distribution of E. macroclada extracted rubber by GPC.

FIGURE 12

Proposed model of the mechanisms involved in E. bicolor latex extract-evoked peripheral, nonopioid analgesia (Basu et al., 2019).

FIGURE 13

Euphol isolated from the latex of E. tirucalli inhibited total number of tumor cell K-562 cells after treatment (12 h). (A) Control cells incubated with RPMI only; (B) control cells incubated with DMSO (0.4%); (C) euphol treatment (23.4 μM); (D) euphol treatment (46.9 μM); (E) imatinib (0.5 μM); and (F) doxorubicin (0.085 μM). v, viable cells; a, apoptotic cells (Cruz et al., 2018).

FIGURE 14

Apoptosis inducing effect of euphol extracted from E. tirucalli was to B16F10 cells after 24 h of treatment with different concentrations of euphol. (A) Control cells incubated with RPMI; (B) control cells incubated with DMSO (0.4%); (C,D) B16F10 cells treated with 70.3 and 35.2 μM of euphol. Cell rounding:, bleb formation:, chromatin condensation:. Magnification = 1,000×, bar = 20 μm (Cruz et al., 2018).

FIGURE 15

Effect of latex treatment on tumor mass and tumor cell proliferation in untreated animals with tumor (W), animals with tumor treated with 25 μL/mL aqueous solution of latex (SW1), and animals with tumor treated with 50 μL/mL aqueous solution of latex at (SW2). Data are presented as the mean + SEM. W, n = 11; SW1, n = 12; SW2, n = 14. *p < 0.05, **p < 0.001, and ***p < 0.0001 (one-way ANOVA followed by a post-hoc Tukey test) (Martins et al., 2020).

FIGURE 16

Morphological changes of HeLa and HRT-18 cells under treatment with latex of E. umbellata (Pax) Bruyn (A,D) controls; cells incubated with RPMI only. (B) HeLa cells incubated with 500 and (C) 750 μg/ml of latex. (E) HRT cells incubated with 750 μg/ml and (F) 1,000 μg/ml of latex (Luz et al., 2015).

FIGURE 17

Photomicrography of Chorioallantoic membrane (CAM) vascular network formation. (A) Inhibitor dexamethasone; (B) the negative control (water); (C) the test solution (E. tirucalli); and (D) the inducer control (Biocure Biomembrane) (Bessa et al., 2015).

FIGURE 18

Histological sections stained with hematoxylin-eosin. Chorioallantoic membranes (CAMs) treated with the inhibitor control (dexamethasone) show few connective tissue cells and few blood vessels (A,B). The inducer control (Biocure Biomembrane of Hevea brasiliensis latex) treatment induced a large number of blood vessels and inflammatory foci (C,D). Treatment with the test solution of Euphorbia tirucalli latex resulted in a large number of well-organized blood vessels and inflammatory foci (E,F) (Bessa et al., 2015).

FIGURE 19

Effect of latex of E. caducifolia on hydroxyproline and DNA content. Values reported as Mean ± SEM (n = 6). The data were analyzed by one way ANOVA followed by and Dunnett’s test. *P0.05 as compared with control group. ECL (latex of E. caducifolia) (Goyal et al., 2012).