Table 4.
Bioactive composition and extraction procedures of Opuntia spp. flowers and roots.
| Species/Variety | Provenance | Extraction Procedure | Main Bioactive Compounds and Levels Found | Main Conclusion | Ref. |
|---|---|---|---|---|---|
| Opuntia ficus-indica | Flowers were collected during the post-flowering stage in June 2013, from wild populations located in Tunisia (latitude 34°46′29″ N, longitude 10°39′73″ E; elevation: 41 m), where the climate is semi-arid, characterized by a mean rainfall of 200 mm/year. | Extraction procedure was performed by using different solvents: water, methanol, acetonitrile, acetone, ethyl acetate, dichloromethane, and hexane. Two different extraction processes were tested: Soxhlet extraction and maceration. | Total phenolic content (mg GAE */g extract) Soxhlet extraction Water: 58.7 Methanol: 270.9 Acetonitrile: 132.4 Acetone: 67.5 Ethyl acetate: 122.3 Dichloromethane: 10.1 Hexane: 7.5 Maceration extraction Water: 44.2 Methanol: 227.8 Acetonitrile: 17.6 Acetone: 70 Ethyl acetate: 70.8 Dichloromethane: 14.7 Hexane: 14.8 Total flavonoid content (mg RE*/g extract) Soxhlet extraction Water: 9.7 Methanol: 60.81 Acetonitrile: 19.4 Acetone: 15.29 Ethyl acetate: 17.65 Dichloromethane: 1.73 Hexane: Not detected Maceration extraction Water: 22.47 Methanol: 27.47 Acetonitrile: 3.25 Acetone: 4.6 Ethyl acetate: 15.75 Dichloromethane: 8.11 Hexane: Not detected |
In terms of extract yield, maceration is more efficient than Soxhlet, and the two best solvents are water and methanol. Regarding the bioactive compounds and antioxidant activity, the solvent’s polarity had a significant effect on antioxidant activity. Aqueous and methanolic extracts have proved to be best in terms of high extraction of phenolic compounds and antioxidant activity. It was proven that the polyphenols are thermostable, and once they are responsible for the antioxidant activity of the flower extracts, the Soxhlet method was the most interesting to preserve the antioxidant activity. |
[51] |
|
Opuntia ficus-indica and Opuntia stricta |
From May to June 2009, the flowers were collected from 4 different flowering stages (vegetative, initial flowering, full flowering, and post-flowering) from wild populations located in Tunisia (latitude 34°46′29″ N, longitude 10°39′73″ E; elevation: 41 m), where the climate is semi-arid and is characterized by a mean rainfall of 200 mm/year. | Maceration was used for extraction using hexane. After 7 days, extracts were filtered and concentrated and finally characterized by Gas Chromatography with flame-ionization detection (GC FID). | Fifty different components were detected, representing around 85–99.7% of the total integrated peak area. No remarkable differences were observed between the flower compositions. Phytochemical compounds present in the Opuntia flower extract essentially belong to carboxylic acids (28–97%), terpenes (0.2–57%), esters (0.2–27%), and alcohol classes (<1.8%). Aromatic compounds, mostly phenolic compounds ((2-methoxy-4-vinylphenol and phenol) represented only 9.3% of the identified molecules. Monoterpenes d1-limonene and linalool were found in small quantities in the early stages of O. ficus-indica flowering, and only at post-flowering for O. stricta. Camphor represented 32.4% of the compounds found in the vegetative stage for O. ficus-indica. In terms of total phenolic content: Opuntia ficus-indica: Vegetative: 16.3 mg GAE */g extract Initial flowering: 13.4 mg GAE */g extract Full flowering: 13.3 mg GAE */g extract Post-flowering: 49.0 mg GAE */g extract Opuntia stricta: Vegetative: 16.7 mg GAE */g extract Initial flowering: 15.3 mg GAE */g extract Full flowering: 13.1 mg GAE */g extract Post-flowering: 80.9 mg GAE */g extract |
The extraction yield increased with the evolution of the flowering stage, with the highest yield found at the post-flowering stage (O. ficus-indica) and for O. stricta at full flowering. Overall, O. stricta presented more phenolic compounds than O. ficus-indica, which corroborates the superior antioxidant activity of its extract. However, the antioxidant power was not related to the number of phenolic compounds; once at the post-flowering stages, it presented the highest content but the lowest activity. This property was attributed to the presence of terpenes and aromatic compounds. The extracts exhibited good antimicrobial activity against Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli, with O. stricta extracts being more active than O. ficus-indica. |
[92] |
| Opuntia ficus-indica (L) Miller | Flowers were collected during the post-flowering stage in June 2014 from wild populations located in Tunisia (latitude 34°46′29″ N, longitude 10°39′73″ E; elevation: 41 m), where the climate is semi-arid, characterized by a mean rainfall of 200 mm/year. | Two flower extracts were evaluated: an aqueous extract (mucilage) and a methanolic extract (Soxhlet extraction). Mucilage extract was characterized in terms of monosaccharide composition by GC. Furthermore, antimicrobial activity was evaluated against Gram-positive and Gram-negative foodborne bacteria. |
Mucilage composition found: Glucose: 32.41 mg/g extract Mannose: 11.46 mg/g extract Arabinose: 7.98 mg/g extract Xylose: 4.97 mg/g extract Galactose: 2.61 mg/g extract Rhamnose: 1.99 mg/g extract Total sugar: 61.4% |
The mucilage yield of th extraction found was 18.3%, while 14.8% was reported for the Soxhlet extract. Glucose was the major component of the mucilage and originated from the plant flower’s hemicellulose and cellulose. Both mucilage and methanolic extracts exhibited antimicrobial activity against both Gram-positive and Gram-negative foodborne bacteria, with a superior effect against the former. The methanolic extract was more efficient against the bacteria tested than mucilage, and the highest inhibition was found against Listeria monocytogenes. In terms of antioxidant properties, the mucilage and methanol extracts exhibited significant anti-radical activity, although the mucilage extract showed lower radical-scavenging activity than the methanolic extract. |
[93] |
| Opuntia ficus-indica (L) Miller | Flowers of O. ficus-indica were collected in Monasterace, Italy, in May 2007. | Dried flowers were subjected to a maceration extraction process using methanol. Purification was performed by using Solid-Phase Extraction. The dried residue was analyzed by High Performance Liquid Chromatography coupled with Photo Diode Array and Electrospray Ionization Gas Chromatography (HPLC-PDA-ESI-MS) for qualitative investigation and by HPLC-PDA for quantitative analysis. Volatiles were analyzed by GC and Gas Chromatography with Electron Impact Mass Spectrometry (GC-EIMS) system. |
O. ficus-indica flower methanol extract composition (mg/g): Quercetin 3-O-rutinoside: 7.09 Kaempferol 3-O-rutinoside: 4.00 Quercetin 3-O-glucoside: 4.47 Isorhamnetin 3-O-robinobioside: 42.69 Isorhamnetin 3-O-galactoside: 9.79 Isorhamnetin 3-O-glucoside: 7.24 Kaempferol 3-O-arabinoside: 3.24 Composition of O. ficus-indica flower volatiles (%): (E)-3-Hexen-1-ol: 3.7 1-Hexanol: 12.3 Nonanal: 2.5 2-Ethyl hexyl acetate: 1.2 Tetrahydrolavandulol: 5.5 1-Nonanol: 1.2 Pinocampheol: 1.7 Dihydrocitronellol: 2.6 Decanal: 8.2 Tridecane: 5.9 cis-2,3-Pinanediol: 1.9 η-Tetradecane: 9.1 β-Ylangene: 1.5 (E)-Geranyl acetone: 4.8 Allo-aromadendrene: 3.9 Germacrene D: 12.6 η –Pentadecane: 4.0 η –Hexadecane: 1.6 |
Secondary metabolites belonging to the flavonol glycoside class were found in the cactus flowers. Total flavonoids of the flowers were 81.75 mg/g of fresh plant material, and Isorhamnetin 3-O-robinobioside was the major component, representing 52.22%, followed by isorhamnetin 3-O-galactoside (11.98%). The flower extract has a pharmaceutical interest as it can be used for the treatment of depression, and its major component is associated with a testosterone 5α-reductase inhibitor. This was the first report on the volatile composition of O. ficus-indica. There were no monoterpene hydrocarbons found, but oxygenated monoterpenes were at 16.5% and sesquiterpene hydrocarbons were at 18%, with Germacrene D as the major component. |
[94] |
| Opuntia ficus-indica f. inermis | The roots were collected from municipal areas of Gafsa, Tunisia. | Extraction from dried roots was performed by using methanol under stirring. The solution was then centrifuged, and the supernatant was dried. Total phenolic compounds and flavonoid content were determined using UV/Vis spectroscopy. | Total phenolic: 57.56 mg GAE */g extract Total flavonoids: 23.5 mg RE*/g extract |
The yield of extraction found was 26%. Root methanolic extract exhibited remarkable content in phenolic and flavonoid compounds. In comparison to swallow root (Decalepis hamiltonii), Opuntia root extract presented almost double the phenolic compounds. Regarding the flavonoid content, Opuntia root extracts reported concentrations superior to those reported for Opuntia fruit extracts, which are known for their antioxidant power. Extracts presented antiulcerogenic activities tested in vivo in rats. Phenolic and flavonoid wealth, radical scavenging activity, and reducing power have been implicated in the extract’s antiulcer properties. |
[95] |
* GAE (Gallic Acid Equivalent), RE (Rutin Equivalent).