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.
1. Introduction
Euphorbia is the third largest genus of flowering plants in the Euphorbiaceae family, with almost 2000 species distributed in tropical and subtropical climate zones. The rich morphological variability and near-cosmopolitan distribution of
Euphorbia have caught attention worldwide since ancient times
[1].
Euphorbia species are readily distinguishable by their specialized inflorescences and milky latex
[1][2][3]. The plants of this genus are commonly used for ornamental and household purposes
[4]. The genus is well known for the chemical diversity of its isoprenoid components
[5]. Some plants of this genus are of great importance, and they have been used as traditional folk medicine to treat skin disease, venomous bites, abdominal pain, abdominal distention, trichiasis, as wart removers, and to treat paralysis
[6].
Chemically, diterpenoids with various core frameworks such as jatrophanes, ingenanes, lathyranes, myrsinols, and tiglianes are the main components found in
Euphorbia. Other reported chemical constituents were sesquiterpenoids, cerebrosides, flavonoids, phloracetophenones, steroids, and glycerols
[5]. Various pharmacological properties have been reported for the genus
Euphorbia including antioxidant, antibacterial, antifungal, antiviral, anti-inflammatory, and cytotoxic effects
[7][8]. The extract of latex of these plants has shown co-carcinogenic activity due to the presence of diterpene esters (tigliane and ingenane), and it has been banned from commercial uses
[9][10]. However, many secondary metabolites found in the latex extract have anticarcinogenic activities
[11][12].
Euphorbia cactus Ehrenb ex Boiss. (Family; Euphorbiaceae) is a perennial succulent leafless spiny shrub with 3–4 angled dark green branches mottled with radiating yellow streaks. It is widely distributed in central Africa and the southern Arabian Peninsula and reaches up to 3 m high. Fruit capsules are dull red 3-angular with 8–9 × 15–16 mm in size
[13]. The extract of
E. cactus latex showed antileishmanial activity
[14], whereas the crude methanolic extract of the whole plant has been reported to exhibit antioxidant, antimicrobial, and anticancer activities
[15]. Considering the pharmacological activity of
E. cactus extracts, different parts of the plants need further investigation.
2. Preliminary Phytochemical Screening
The phytochemical study of ECME revealed a broad diversity of phytochemicals. The major phytochemical constituents included phenols, diterpenes, flavonoids, sesquiterpenoids, terpenoids, anthocyanins, tannins, steroids, anthraquinones, carbohydrates, cerebrosides, phloracetophenones, glycerols, and alkaloids were present in the methanol extract (Table 1).
Table 1. Qualitative screening of phytoconstituents present in the methanolic extract of aerial parts of E. cactus (ECME).
Phytochemicals |
ECME |
Phenols |
+++ |
Flavonoids |
++ |
Diterpenes |
+++ |
Sesquiterpenoids |
++ |
Terpenoids |
++ |
Anthocyanins |
++ |
Tannins |
++ |
Steroids |
++ |
Cerebrosides |
+ |
Anthraquinones |
++ |
Phloracetophenones |
+ |
Glycerols |
+ |
Alkaloids |
+ |
Carbohydrates |
++ |
Saponins |
- |
3. Antioxidant Activity
A free radical is a molecular species containing an unpaired electron and is engaged in bacterial, fungal, and parasitic infections, inflammation, atherosclerosis, lung damage, reperfusion injury, aging, neoplastic, and cardiovascular and autoimmune disorders
[16][17]. The results demonstrated that ECME exerted free radical scavenging activity in vitro models including DPPH
• and FIC assays.
3.1. Free Radical Scavenging Activity (DPPH•)
DPPH
• free radicals are widely used for investigating the preliminary radical scavenging effect of the plant extract
[18]. Scavenging of DPPH
• radical is associated with lipid peroxidation inhibition
[19]. DPPH
• is a substance used to test antioxidant activity
[20]. Antioxidants either shift a hydrogen atom or an electron to the DPPH
• and neutralize its free radical feature
[21]. DPPH
• test is based on the ability of stable DPPH
• free radical to decolorize in the presence of antioxidants and is considered a reliable procedure for determining the action of radical scavenging
[22]. Several studies in the literature have addressed the free radical scavenging activity of different
Euphorbia species
[23][24][25][26]. In the current study, the highest inhibition percentage was observed with ECME (89.75), followed by compound
3 (69.35) and compound
4 (62.21) at 200 µg mL
−1 (
Table 2). Furthermore, it was observed that ECME displayed more pronounced scavenging activity, in contrast to isolated compounds as well as BHT standard (
Table 2). This result could be attributed to the synergistic effect of isolated compounds
1–
4 or other minor components present in the extract.
Table 2. Free radical scavenging (DPPH•) and ferrous ion chelating (FIC) activity of ECME and isolated phytochemicals.
Sample |
DPPH• Radical Scavenging |
Ferrous Ion Chelating Activity |
Concentration (µg mL−1) |
Inhibition (%) |
Concentration (µg mL−1) |
Inhibition (%) |
ECME |
200 |
89.75 ± 0.35 |
3000 |
36.12 ± 0.45 |
Compound 1 |
200 |
52.34 ± 0.26 |
3000 |
41.23 ± 0.26 |
Compound 2 |
200 |
49.12 ± 0.34 |
3000 |
53.14 ± 0.22 |
Compound 3 |
200 |
69.35 ± 0.24 |
3000 |
56.24 ± 0.36 |
Compound 4 |
200 |
62.21 ± 0.14 |
3000 |
62.45 ± 0.42 |
BHT |
200 |
41.16 ± 0.36 |
- |
- |
EDTA |
- |
- |
3000 |
95.58 ± 0.45 |
3.2. Ferrous Ion Chelating Assay (FIC)
Iron is an essential metal for life and plays a crucial role in the transport of oxygen, respiration and activity of various enzymes. However, it is a highly reactive metal and catalyzes oxidative changes in proteins, lipids and other components of the cell
[27]. The metal chelating capacity of ECME was determined by the ferrous ion ferrozine-Fe
2+ complex formation. Ferrous ions unite with ferrozine, resulting in a red-colored complex that shows absorbance at 562 nm
[28]. Chelating agents forming σ bonds with the metal are considered effective secondary antioxidants as they have the ability to decrease the redox potential and stabilize the metal ion in its oxidized form
[28]. The iron-binding ability of ECME and isolated compounds
1–
4 were measured as a percentage of inhibition, and compound
4 showed the highest potential (62.45%), followed by compound
3 (56.24%) and compound
2 (53.14%) at 3000 µg mL
−1 concentrations (
Table 2). However, ECME and compound
1 exhibited moderate effects at similar concentrations, which was not comparable to that of the EDTA reference standard.
This entry is adapted from the peer-reviewed paper 10.3390/plants11050681