- Open Access
Characterization, antioxidant, and cytotoxic effects of some Egyptian wild plant extracts
Beni-Suef University Journal of Basic and Applied Sciences volume 10, Article number: 13 (2021)
Natural products from plants are very safe as compared to synthetic ones, so the aim of this study was to assess the in vitro antioxidant and antitumor activities of the ethanolic extracts of four Egyptian wild plant species (Varthemia candicans, Peganum harmala, Suaeda vermiculata, and Conyza dioscoridis), as well as polyphenols and flavonoid contents with gas chromatography–mass spectrometry (GC-MS). The antioxidant activity of the four plant extracts was assessed using 2,2-diphenyl-1-picrylhydrazyl (DPPH) to determine 50% inhibition of DPPH radical scavenging activity and reducing power by phosphomolybdate assay. In addition, the chemical composition of the four sample extracts was investigated using GC-MS. The total phenolic and flavonoid levels were also determined. Then, the antitumor activity of the plant extracts against HepG2 cells was determined using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.
The results showed that Varthemia candicans extract was the highest one regarding both polyphenols and flavonoid contents. Moreover, the extract of Suaeda vermiculata exhibited the lowest half maximum inhibitory concentration (IC50) against DPPH, thus indicating its highest effectiveness. All studied plant extracts decreased the viability of HepG2 cells, in a dose- and time-dependent manner, and the lowest IC50 was for Suaeda vermiculata.
The investigated plant extracts showed potent antioxidant and antitumor activities in vitro due to their phytochemical contents.
Medicinal plants contain, aside from primary metabolites, secondary metabolites, like flavonoids, alkaloids, phenolics, tannins, glycosides, and steroids, which are very important alternative medicines whether in a single form or in combination . These plants are cheap and available for all people, especially the Third World, and could be used as antioxidants against free radicals that cause many human diseases .
The wild Egyptian plant Conyza dioscoridis was potentially used in the treatment of many diseases like rheumatism, intestinal distension, and cramps in folk medicine . A previous study has emphasized the medicinal significance of C. dioscoridis plant as anti-diarrheal and diuretic . Additionally, the volatile constituents of C. dioscoridis showed potential antimicrobial activity against many pathogenic microorganisms , and its aerial parts extract owned anti-inflammatory activity . Moreover, the species C. dioscoridis has been also reported to encompass antioxidant and antihyperglycemic constituents . Secondary phytochemical metabolites including hydrolyzable tannins, alkaloids, flavonoids, essential oils, terpenoids, and polyphenols have been reported in Conyza species ; these therapeutically active components have raised its medicinal significance. However, as far as we are aware, nothing has been traced concerning either plant constituents or anticancer activity. For example, the hydrolyzable tannins showed the free radical scavenging capacity because they can donate a hydrogen atom and form a stable quinone [9,10,11]. In addition, a previous study indicated the essential oils’ therapeutic potential which included antimicrobial, anticancer, skin permeation enhancing, and antiviral effects . In addition, plant terpenoids have been used in food and pharmaceutical industries .
The second plant in this work is Varthemia candicans, a member of the family Asteraceae, which has been reported to be a competent treatment for some diseases in folk medicine. Phytochemical constituents of V. candicans showed that it contains many prophylactic components such as sesquiterpenes, sesquiterpene-lactone derivatives, polymethoxylated flavonoids, and coumarins . Plant sesquiterpenes are known to have diverse biological and therapeutical activities, including antineoplastic agents. Another detailed study on the active pharmaceutical constituents of V. candicans revealed that its aerial parts encompass a variety of flavonoids, alkaloids, phenols, and saponins, which possess medicinal and antioxidant properties .
Suaeda vermiculata is a halophytic member of the family Chenopodiaceae, which grows naturally in the Egyptian coastal region. Some earlier works concerned with prophylactic characteristic of wild plants showed that S. vermiculata has high quantities of phenolics and flavonoids with a pronounced antioxidant activity . Additionally, S. vermiculata has been demonstrated to have hypoglycemic, hypolipidemic, and antitumor activities. Such activities were attributed to polyphenolic compounds (including flavonoids) in the aerial parts of the plant . Nevertheless, triterpenoids and polyphenols in S. vermiculata increased the pharmacological importance of the plant due to its role in preventing cardiovascular and cancer diseases .
Peganum harmala is a member of the Zygophyllaceae family with a long history in traditional medicine as being widely used to treat apoplexia, asthma, jaundice, and lumbago. Recently, some alkaloidal species like β-carboline and quinazoline has been identified as principal components in P. harmala aerial parts. These alkaloidal species have been reported to encompass pharmacological and remedial properties, such as antimicrobial, antiparasitic, analgesic, and antitumor .
In this work, the volatile constituents of the ethanolic extracts of four wild Egyptian plants: Conyza dioscoridis, Varthemia candicans, Suaeda vermiculata, and Peganum harmala, were quantified by means of GC-MS. Additionally, their phenolic and flavonoid contents, as well as their antioxidant activities, were evaluated. Subsequently, the antitumor activity of the plant extracts against HepG2 cell line was evaluated.
Collection of plant material
The investigated four wild plant species collectively known as Varthemia candicans (Del.) Boiss., Peganum harmala L., Suaeda vermiculata Forssk., and Conyza dioscoridis L. were collected during the summer season (August 2015) from Borg El Arab city (North West Costal region), Alexandria, Egypt. Voucher specimens were deposited in the herbarium of the Botany Department, Faculty of Science, Tanta University (TANE) (Table 1). The collected samples were washed thoroughly with tap water then dist. water and the leaves were separated from the aerial parts. Leaf samples were oven dried at 40 °C for 5 days, ground into a fine powder using an electric mixer, and sieved through 0.2 mm sieve to uniform size particle then kept in paper pages at 4 °C for further investigation.
Cell culture grade dimethyl sulfoxide (DMSO), 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), phosphate-buffered saline (PBS), fetal bovine serum (FBS), Dulbecco’s modified Eagle medium (DMEM), penicillin/streptomycin, Quercetin, and 2,2-diphenyl-1-picrylhydrazyl (DPPH), all analytical grade chemicals, were purchased from Sigma-Aldrich (St Louis, USA). Folin–Ciocalteu reagent, potassium ferricyanide, ammonium molybdate, ethanol, sodium hydroxide, chloroform, anhydrous sodium sulfate, sulfuric acid, sodium carbonate, and gallic acid were purchased from Cornell Lab (Cairo, Egypt). Cisplatin (Cytoplatin-50) was purchased from Verna Industrial Estate, France.
Preparation of sample extract
Twenty-five grams of each plant material was extracted using 80% aqueous ethanol in a Soxhlet assembly for 16 h. The obtained extracts were filtered twice through Whatman No. 1 filter papers then subjected to reduced-pressure evaporation at 40 °C using a rotary evaporator. The residue remaining after evaporation was used in calculating the yield per each extract (Table 2) then stored at 4 °C for further analysis and investigations. At the time of phytochemical analysis and antitumor activity, pellets were dissolved in 10% DMSO.
Quantitative analysis of plant extracts
Total phenolic contents
The total phenolic content of sample extract was determined spectrophotometrically using the Folin–Ciocalteu method . Briefly, 0.1 ml of the plant extract was mixed with 2.8 ml of deionized water, 2 ml of 20% sodium carbonate, and 0.1 ml of 50% Folin–Ciocalteu reagent. After incubation at room temperature for 30 min, the absorbance of the reaction mixture was measured at 750 nm. Gallic acid (GA) was used as a standard phenol for construction of the standard graph and the total phenolics were expressed as mg gallic acid equivalents (GAE)/g d.wt.
Total flavonoid content
Flavonoids in the investigated samples were determined according to the aluminum chloride colorimetric method . Aliquot of 0.5 ml extract was mixed with 1.5 ml of 95% ethanol, 0.1 ml of 10% aluminum chloride hexahydrate, 0.1 ml of 1 M potassium acetate, and 2.8 ml of distilled water. Following incubation at room temperature for 40 min, the reaction mixture absorbance was measured at 415 nm. Quercetin was chosen as a standard flavonoid for constructing a standard curve and flavonoids were expressed as mg quercetin equivalents (QE)/100 g d. wt.
DPPH radical scavenging activity
The electron-donating ability of the investigated extracts was measured by bleaching a purple solution of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical according to the method of Sermakkani and Thangapandian . Aliquot of 0.1 ml extract (20, 40, 60, 80, 100 μg/ml) was added to 3.9 ml of 36 mg/l DPPH–methanol solution. After incubation for 1 h in the dark at room temperature, the absorbance was determined against blank at 515 nm. The percentage inhibition of free radical DPPH was calculated from (Ablank − Asample/Ablank) × 100, where Ablank is the absorbance of the control reaction and Asample is the absorbance in the presence of plant extract. The concentration of extract that caused 50% inhibition (IC50) was calculated from the regression equation for the concentration of extract and percentage inhibition. Ascorbic acid was used as a positive control.
Total antioxidant capacity using phosphomolybdate reagent
The assay is based on the reduction of Mo(VI) to Mo(V) by the extract and subsequent formation of a green phosphate–Mo(V) complex at acid pH . An aliquot (0.1 ml) of plant extract containing 100 μg/ml phenol was added to 1 ml of reagent solution (0.6 mol/l H2SO4, 28 mmol/l Na3PO4, and 4 mmol/l ammonium molybdate). The tubes were incubated in a thermal block at 95 °C for 90 min. Once the mixture had cooled to room temperature, the absorbance of each solution was measured at 695 nm against a blank. Antioxidant capacity was expressed as mg ascorbic acid equivalent per gram dry weight (mg ascorbic acid (mg/g d. wt).
Preparation of samples for GC-MS analysis
All samples were dissolved in chloroform after removal of DMSO for GC-MS analysis.
Gas chromatography–mass spectrometry (GC-MS) analysis
The chemical composition of the studied samples was performed using a Trace GC Ultra-ISQ mass spectrometer (Thermo Scientific, USA). The column type is TG–5MS (30 m × 0.25 mm × 0.25 μm film thickness), and the oven temperature was initially held at 60 °C, then increased by 5 °C/min to 150 °C withhold 2 min, and then increased to 280 °C with the rate of 10 °C/min. The inlet and transfer line temperatures were kept at 250 °C. Helium was used as a carrier gas at a constant flow rate of 1 ml/min. The solvent delay was 3 min and diluted samples of 1 μl were injected automatically using Autosampler AS3000 coupled with GC in the split mode. EI mass spectra were collected at 70 eV ionization voltages over the range of m/z 40–650 in full scan mode. The ion source temperature was set at 200 °C. All obtained components of the studied extracts were identified by comparison of their retention times and mass spectra with those of WILEY 09 and NIST 11 mass spectral databases.
Human hepatocellular carcinoma cells (HepG2) supplied by tissue culture unit in Vacsera Institution (Cairo, Egypt) were grown in DMEM medium supplemented with 10% FBS, 2 mM glutamine, 100 μg/ml of streptomycin, and 100 U/ml of penicillin in an incubator at 37 °C and 5% CO2.
Overall cell activity—MTT assay
The MTT assay based on the method of Mitry et al.  measures the metabolism of 3-(4, 5-dimethylthiazol-2yl)-2, 5-biphenyl tetrazolium bromide to form an insoluble formazan precipitate by mitochondrial dehydrogenases only present in viable cells. The samples were tested at a concentration of 100 μg/ml phenolic content in 1% DMSO to establish its cytotoxic activity on HepG2 liver carcinoma cell line. To determine the half-maximal inhibitory concentration (IC50), the samples were tested in serial dilutions (5, 10, 20, 50, and 100 μg gallic acid equivalent/ml) in triplicate. The results of IC50 were compared to cisplatin (2, 4, 8, 16, and 24 μg/ml) as a reference antitumor drug according to Qin and Ng .
The culture medium was removed from the 96-well microplates after 48 h of the drug (extract or cisplatin) treatment, cells were washed gently twice with ice-cold PBS, and 200 μl of 0.5 mg/ml of MTT solution was added per well. The microplate was incubated at 37 °C for 4 h in a cell culture incubator. After incubation, 180 μl medium/MTT was removed and 100 μl of acidified isopropanol was added per well. In order to dissolve the formazan produced, the microplate was incubated with shaking (at the highest speed) for 15 min at room temperature. Using a microplate reader, the absorbance of each well was measured at 630 nm.
Replicate means ± standard deviations were computed by Student’s paired two-tailed t test using Graph Pad software. Dose–response in proliferation rate experiments was evaluated by analysis of variance (ANOVA) and P < 0.05 was considered statistically significant.
Total phenolic and flavonoid contents of extracts
Data represented in Table 3 summarize the total phenolic and flavonoid content in the ethanolic extracts of four Egyptian wild plants (Varthemia candicans, Peganum harmala, Suaeda vermiculata, and Conyza dioscoridis). The total phenolic content of V. candicans showed a mean value of 119.0 mg GAE/100 g d.wt., which was the uppermost value among the studied plants. Meanwhile, the total phenolic content of P. harmala, S. vermiculata, and C. dioscoridis recorded mean values of 43.0, 83.0, and 70.0 mg GAE/100 g d.wt., respectively. Thus, the higher content of phenolics subsequent to V. candicans has been recorded in S. vermiculata, while the lower content has been obtained in P. harmala extract. Different phenolic compounds have different responses in the Folin–Ciocalteu method.
Our results showed that V. candicans possessed the highest flavonoid content compared to other tested plants (96.2 mg QE/100 g d. wt.). This result was in conformity with those recorded in phenol content results (Table 1). The extracts of P. harmala, S. vermiculata, and C. dioscoridis showed mean values of 8.8, 16.5, and 70.4 mg QE/100 g d. wt., respectively. On the other hand, the lowest flavonoid content was recorded in P. harmala extract. This result runs parallel with phenol content results (Table 1).
DPPH radical scavenging and total antioxidant activities
The radical scavenging activity (RSA) expressed as 50% DPPH radical scavenging and the total antioxidant capacity (TAC) as measured through phosphomolybdate assay of the four studied plant extracts are represented in Fig. 1. The results showed that S. vermiculata possessed the highest RSA as it resulted in the lowest 50% DPPH activity followed by C. dioscoridis and V. candicans, whereas the lowest RSA was observed in P. harmala extract, as compared with the reference antioxidant ascorbic acid (Fig. 1a). The IC50 values of the aforementioned plant extracts were 2.8, 15.8, 22.1, and 128.8 μg/ml for S. vermiculata, C. dioscoridis, V. candicans, and P. harmala, respectively; meanwhile, the IC50 value of the standard ascorbic acid was 15.0 μg/ml. Thus, the proceeding data confirmed that the extract of S. vermiculata has a high bleaching activity towards the free radical DPPH more than other plant extracts and the standard ascorbic acid.
In order to validate the obtained data, the total antioxidant capacity (as μg ascorbic acid equivalent/g d.wt) using phosphomolybdate assay was determined (Fig. 1b). The present study demonstrated that V. candicans exhibited the highest antioxidant capacity for phosphomolybdate reduction compared to other plant extracts.
The order of decreasing antioxidant activity in the ethanolic extracts of plants was V. candicans > S. vermiculata > C. dioscoridis > P. harmala with values of 368.2, 216.9, 165.0, and 92.9 μg ascorbic acid equivalent/g d.wt, respectively. This order is similar to the phenolic contents of the extracts that showed the extent of antioxidant activity of the extract is in accordance with the amount of phenolics present in that extract.
Identification of experimental sample components using the GC-MS technique
The GC-MS analysis of the ethanolic extract of V. candicans revealed the identity of 24 compounds (Table 4). Panaxatriol, 9,12-octadecadienoic acid (Z,Z)-, cis-9-octadecenoic acid, 1-heptatriacotanol, hexadecatrienoic acid, methyl ester, and 3à,5à-cyclo-ergosta-7,9(11),22t-triene-6á-ol are the main identified compounds representing 25.88, 25.65, 7.60, 5.21, 3.80, and 3.25%, respectively. At the main time, the results of GC-MS revealed that other active phytochemical compounds are dominated in the ethanolic extract of V. candicans belonging to fatty acids (2,5-octadecadienoic acid, methyl ester, 7,10,13-eicosatrienoic acid, methyl ester, 8,11,14-docosatrienoic acid, methyl ester, 9-octadecenoic acid (Z)-, 9-hexadecenyl ester, (Z)- and oleic acid,3-(octadecyloxy) propyl ester), fatty alcohols (13-heptadecyn-1-ol and 1-heptatriacotanol), sterols (cholestan-3-ol, 2-methylene-, (3á,5à)-, stigmastan-3,5-diene, stigmast-5-en-3-ol, (3á)- and 3à,5à-cyclo-ergosta-7,9(11),22t-triene-6á-ol), terpenoids (fischeroside C), carotenoids (lycopene), and siloxane derivatives (trisiloxane, 1,1,1,5,5,5-hexamethyl-3-(4-methylpentyl)-3-[(trimethylsilyl)oxy]-,1,1,3,3,5,5,7,7,9,9,11,11-dodecamethyl-hexasiloxane and 1,1,3,3,5,5,7,7,9,9-decamethyl-pentasiloxane).
The results of the GC-MS analysis of P. harmala ethanolic extract showed the identity of 14 compounds belonging to different chemical classes (Table 5). The most prominent compounds are represented in hexadecatrienoic acid, methyl ester (63.13%), Cis-9-octadecenoic acid (11.43%), and 6-ethoxyquinaldine (6.00%). Moreover, other phytochemical constituents were identified in the ethanolic extract of P. harmala belonging to quinolines (5-Cyano-1,2,3,4-tetrahydro-2-methylisoquinoline and 4-Acetamido-1,2,3,4-tetra hydroisoquinoline), carotenoids (rhodopin), corticosteroids (betamethasone valerate), fatty acids (hexadecanoic acid, ethyl ester, 8,11-octadecadienoic acid, methyl ester, 2,5-octadecadienoic acid, methyl ester, 6-octadecenoic acid, (Z)-, 5,8,11,14,17-eicosapentaenoic acid, methyl ester and 4,7,10,13,16,19-docosahexaenoic acid, methyl ester), and fatty acid derivatives (9-octadecenamide, (Z)-).
As for C. dioscoridis ethanolic extract, 13 compounds were identified by the GC-MS technique (Table 6). The most abundantly identified compounds were the fatty acids 9,12-octadecadienoic acid (Z,Z); 9,12,15-octadecatrienoic acid, 2,3-dihydroxypropyl ester, (Z,Z,Z); and 9-octadecenoic acid, eicosyl ester, (9Z) (41.54, 7.86, and 5.40%, respectively) and the phytosterol stigmast-5-en-3-ol, (3á) (7.84%). Moreover, the results showed the existence of other fatty acids (6,9-octadecadienoic acid, methyl ester, 9-octadecenoic acid (Z), 4,7,10-hexadecatrienoic acid, methyl ester, 10,13-eicosadienoic acid, methyl ester, ethyl linoleate and 9-octadecenoic acid (Z)), vitamin A derivative (vitamin A aldehyde), and luteolin derivative (luteolin 6,8-di-C-glucoside) in the ethanolic extract of C. dioscoridis (Table 6).
The GC-MS analysis of S. vermiculata ethanolic extract predominantly revealed the presence of 10 phytochemical compounds belonging to different classes (Table 7). The main constituents of this extract were hexasiloxane, 1,1,3,3,5,5,7,7,9,9,11,11-dodecamethyl (25.66%); stearic acid, 3-(octadecyloxy)propyl ester (21.37%); fucoxanthin (14.43%); astaxanthin (13.89%); and 2-(4-ethoxy-3-methoxy-phenyl)-3-nitro-2H-chromene (10.90%). Furthermore, S. vermiculata extract comprised other two fatty acid derivatives (octadecanoic acid, 2-(hexadecyloxy)ethyl ester and hexadecanoic acid, 2-[(trimethylsilyl)oxy]-1,3-propanediyl ester) and two carotenoid derivatives (rhodoviolascin and canthaxanthin), in addition to the isoprenylated flavonoid (cyclomulberrin).
These data revealed that the plant extracts are a good source of many bioactive compounds like 9,12-octadecadienoic acid (Z,Z), hexadecatrienoic acid, methyl ester, stearic acid, astaxanthin, and Stigmast-5-en-3-ol, (3á).
In vitro anticancer activity
To evaluate the anticancer activity of the ethanolic extracts of the investigated plants, the extracts were initially tested for cytotoxicity against HepG2 cells as in vitro model of hepatocellular carcinoma cells. The cytotoxic activity was determined by the MTT assay.
HepG2 cells were treated with different concentrations of plant extracts as polyphenol content (5–100 μg/ml) and compared with cisplatin as the reference drug (IC50 = 9.4 μg/ml). The results demonstrated that the investigated plant extracts decreased the viability of HepG2 cells, in a dose- and time-dependent manner. The cytotoxic activities are expressed as IC50 values (Fig. 2). The lower IC50 represents the higher potency of a compound to inhibit the growth of cells and cause toxicity leading to cell death.
Cytotoxic activity of S. vermiculata against human HepG2 cells showed the lowest IC50 value (25.9 μg/ml) (Table 7). Meanwhile, other plant species showed the order of P. harmala, C. dioscoridis, and V. candicans with IC50 values of 56.7, 59.5, and 89.5 μg/ml, respectively. Subsequently, the ethanolic extract of S. vermiculata showed potential anticancer activity against HepG2 cells compared with the other plant extracts.
Plants are a valuable gift of nature for mankind. They are the source of a diversity of phytochemicals, and they are capable of synthesizing a variety of secondary metabolites. The therapeutic actions of plants unique to particular plant species or groups are consistent with the concept that the combination of secondary products in a particular plant is taxonomically distinct. It has been reported that about 85–90% of the world’s population consumes traditional herbal medicines . In recent decades, studies on phytochemical constituents of medicinal plants and their pharmacological activities have received wide attention. A recent study had reported the presence of medicinal phytochemical constituents like phenolics, flavonoids, and alkaloids in methanolic extracts of V. candicans and S. vermiculata . Based on this study, we determined two important phytochemical classes, total phenolics and total flavonoids, in the ethanolic extracts of four Egyptian plant species (V. candicans, P. harmala, S. vermiculata, and C. dioscoridis). Furthermore, we assessed their phenols and flavonoids as well as antioxidant activities, in addition to their antitumor activities against the hepatocellular cell line HepG2.
Natural antioxidants are very effective to fight against oxidative stress. Medicines derived from plant products are safer than their synthetic counterparts. Recently, the exploration of natural antioxidant compounds has gained considerable attention . The antioxidant response varies remarkably depending on the chemical structure of phenolic compounds . Phenolic compounds of plants fall into several categories. Chief among these are the flavonoids which have potent antioxidant activities . Flavonoids are naturally occurring in plants which have positive effects on human health. They have a wide range of biological activities like antibacterial, antiviral, anti-inflammatory, anticancer, and anti-allergic activities, in addition to their potent scavenger activity against free radicals implicated in many diseases . These results are in accordance with those obtained by . As reported previously, the potential of flavonoids to act as antioxidant depends on their molecular structure. The position of the OH group and other features in the chemical structure of flavonoids are important for their antioxidant and free radical scavenging activities .
Antioxidants fight against free radicals. The latter are known to play a definite role in a wide variety of pathological manifestations. Antioxidants exert their action either by protecting the antioxidant defense mechanisms or scavenging the reactive oxygen species . The electron donation ability of natural products can be measured by DPPH assay. The assay is based on scavenging of DPPH through the addition of a radical species or antioxidant that decolorizes the DPPH solution. The degree of color change is proportional to the concentration and potency of the antioxidants. A decrease in the absorbance of the reaction mixture indicates significant free radical scavenging activity of the tested compound . Our results suggest that the plant extracts contain active constituents that are capable of donating hydrogen to a free radical to scavenge the potential damage. Phenolic contents and flavonoids may be the major contributors for the antioxidant activity as the IC50 values of radical scavenging activity of the investigated ethanolic extracts. It has been reported that many flavonoids and related polyphenols contribute to the phosphomolybdate scavenging activity of medicinal plants . A previous study by  indicated the close relationship between total phenolic content and antioxidative activity of plants.
Gas chromatography–mass spectroscopy (GC-MS) is a valuable tool for the reliable identification of phytocompounds. This technique has been used in defining many active components with valuable therapeutical activities in the extracts of the studied plant species (Tables 4, 5, 6, and 7).
The anticancer activity of the ethanolic extracts of the investigated plants is based on MTT conversion into formazan with water-insoluble crystals via dehydrogenases in the mitochondria of alive cells with a dose-dependent manner . The cytotoxic effect of S. vermiculata may be attributed to the presence of astaxanthin which is considered to be a major component, in addition to stearic acid. Our results were in agreement with those obtained by Khan et al. , who reported that stearic acid, as an ester derivative, inhibits the growth of human breast cancer cells. The anticancer activity of astaxanthin was reported in many studies [68, 69]. The anticancer activity of the study plants may be attributed to the presence of high content of fatty acids and fatty acid esters.
In conclusion, the present study showed that the four plant extracts significantly varied in their contents of polyphenols, flavonoids, antioxidant capacity, and antitumor activity. The highest contents of polyphenols, flavonoids and antioxidant capacity were recorded in V. candicans extract. However, the highest DPPH scavenging and antitumor activities were reported in the extract of S. vermiculata. The antioxidant and antitumor activities of the extracts are mainly dependent on their active constituents. Moreover, further studies are required to investigate the mode of action and the in vivo anticancer activities of the studied extracts.
Availability of data and materials
Patle TK, Shrivas K, Kurrey R, Upadhyay S, Jangde R, Chauhan R (2020) Phytochemical screening and determination of phenolics and flavonoids in Dillenia pentagyna using UV-vis and FTIR spectroscopy. Spectrochim Acta A Mol Biomol Spectrosc. 242:118717
Sekhon-Loodu S, Rupasinghe HP (2019) Evaluation of antioxidant, antidiabetic and antiobesity potential of selected traditional medicinal plants. Front Nutr 6:53
Atta AH, El-Sooud KA (2004) The antinociceptive effect of some Egyptian medicinal plant extracts. J Ethnopharmacol 95:235–238
Atta AH, Nasr SM, Mouneir SM, Al Wabel NA, Essawy SS (2010) Evaluation of the diuretic effect of Conyza dioscorides and Alhagi maurorum. Int J Pharm Pharm Sci 2:162–165
El-Hamouly MMA, Ibraheim MT (2003) GC/MS analysis of the volatile constituents of individual organs of Conyza dioscorides L.(Desf.), growing in Egypt. Alex J Pharm Sci 17:75–80
Awaad AS, El-Meligy RM, Qenawy SA, Atta AH, Soliman GA (2011) Anti-inflammatory, antinociceptive and antipyretic effects of some desert plants. J Saudi Chem Soc 15:367–373
El Zalabani SM, Hetta MH, Ross SA, Abo Youssef A, Zaki M, Ismai A (2012) Antihyperglycemic and antioxidant activities and chemical composition of Conyza dioscoridis (L.) Desf. DC. growing in Egypt. Aust J Basic Appl Sci 6:257–265
Shahwar D, Raza MA, Saeed A, Riasat M, Chattha FI, Javaid M, Ullah S (2012) Antioxidant potential of the extracts of Putranjiva roxburghii, Conyza bonariensis, Woodfordia fruiticosa and Senecio chrysanthemoids. African J Biotechnol 11:4288–4295
Croft KD (1998) The chemistry and biological effects of flavonoids and phenolic acids. Ann N Y Acad Sci 854:435–442
Valverde Malaver CL, Colmenares Dulcey AJ, Rial C, Varela RM, Molinillo JMG, Macías FA, Isaza Martínez JH (2019) Hydrolysable tannins and biological activities of Meriania hernandoi and Meriania nobilis (Melastomataceae). Molecules. 24(4):746
Sakagami H, Jiang Y, Kusama K, Atsumi T, Ueha T, Toguchi M, Iwakura I, Satoh K, Ito H, Hatano T, Yoshida T (2000) Cytotoxic activity of hydrolyzable tannins against human oral tumor cell lines--a possible mechanism. Phytomedicine 7(1):39–47
Aziz ZAA, Ahmad A, Setapar SHM, Karakucuk A, Azim MM, Lokhat D, Rafatullah M, Ganash M, Kamal MA, Ashraf GM (2018) Essential oils: extraction techniques, pharmaceutical and therapeutic potential - a review. Curr Drug Metab 19(13):1100–1110
Tholl D (2015) Biosynthesis and biological functions of terpenoids in plants. Adv Biochem Eng Biotechnol 148:63–106
Al-Tohamy R, Ali SS, Saad-Allah K, Fareed M, Ali A, El-Badry A, El-Zawawy NA, Wu J, Sun J, Mao G-H, others (2018) Phytochemical analysis and assessment of antioxidant and antimicrobial activities of some medicinal plant species from Egyptian flora. J Appl Biomed 16:289–300
Ahmed FA, Elhaak MA, Saad-Allah KM, Kashlana MI (2016) Seasonal variation in prophylactic secondary metabolites of Varthemia candicans in two coastal habitats in Egypt. Egypt J Desert Res 66:1–17
Ibrahim AY, Mahmoud K, El-Hallouty SM (2011) Screening of antioxidant and cytotoxicity activities of some plant extracts from Egyptian flora. J Appl Sci Res 7:1246–1257
Oueslati S, Ksouri R, Falleh H, Pichette A, Abdelly C, Legault J (2012) Phenolic content, antioxidant, anti-inflammatory and anticancer activities of the edible halophyte Suaeda fruticosa Forssk. Food Chem 132:943–947
Stagos D, Amoutzias GD, Matakos A, Spyrou A, Tsatsakis AM, Kouretas D (2012) Chemoprevention of liver cancer by plant polyphenols. Food Chem Toxicol 50:2155–2170
Wang C, Zhang Z, Wang Y, He X (2015) Cytotoxic indole alkaloids against human leukemia cell lines from the toxic plant Peganum harmala. Toxins (Basel) 7:4507–4518
Meda A, Lamien CE, Romito M, Millogo J, Nacoulma OG (2005) Determination of the total phenolic, flavonoid and proline contents in Burkina Fasan honey, as well as their radical scavenging activity. Food Chem 91:571–577
Chang C, Yang M, Wen H (2002) Estimation of total flavonoid content in propolis by two complementary colorimetric methods. J Food Drug Anal 10:178–182
Sermakkani M, Thangapandian V (2010) Phytochemical screening for active compounds in Pedalium murex L. Recent Res Sci Technol 2:110–114
Umamaheswari M, Chatterjee TK (2008) In vitro antioxidant activities of the fractions of Coccinia grandis L. leaf extract. African J Tradit Complement Altern Med 5:61–73
Mitry RR, Hughes RD, Bansal S, Lehec SC, Wendon JA, Dhawan A (2005) Effects of serum from patients with acute liver failure due to paracetamol overdose on human hepatocytes in vitro. Transplant Proc 37:2391–2394
Qin LF, Ng IOL (2002) Induction of apoptosis by cisplatin and its effect on cell cycle-related proteins and cell cycle changes in hepatoma cells. Cancer Lett 175:27–38
Duke J, Bogenschutz MJ (1994) Dr. Duke’s phytochemical and ethnobotanical databases. Washington, DC: USDA, Agricultural Research Service
Al-Rubaye AF, Kadhim MJ, Hameed IH (2019) Determination of bioactive chemical composition of methanolic leaves extract of Sinapis arvensis using GC-MS technique. Int J Toxicol Pharmacol Res 9:163–178
Sujatha S, Anand S, Sangeetha KN, Shilpa K, Lakshmi J, Balakrishnan A, Lakshmi BS (2010) Biological evaluation of (3β)-STIGMAST-5-EN-3-OL as potent anti-diabetic agent in regulating glucose transport using in vitro model. Int J Diabetes Mellit 2:101–109
Baskaran G, Salvamani S, Ahmad SA, Shaharuddin NA, Pattiram PD, Shukor MY (2015) HMG-CoA reductase inhibitory activity and phytocomponent investigation of Basella alba leaf extract as a treatment for hypercholesterolemia. Drug Des Devel Ther 9:509–517
Elezabeth VD, Arumugam S (2014) GC-MS analysis of ethanol extract of Cyperus rotundus leaves. Int J Curr Biotechnol 2:19–23
Alqahtani FY, Aleanizy FS, Mahmoud AZ, Farshori NN, Alfaraj R, Al-sheddi ES, Alsarra IA (2018) Chemical composition and antimicrobial, antioxidant, and anti-inflammatory activities of Lepidium sativum seed oil. Saudi J Biol Sci 26:1089–1092
Romeo FV, Fabroni S, Ballistreri G, Muccilli S, Spina A, Rapisarda P (2018) Characterization and antimicrobial activity of alkaloid extracts from seeds of different genotypes of Lupinus spp. Sustainability 10:788
Durán-Peña MJ, Ares JMB, Collado IG, Hernández-Galán R (2014) Biologically active diterpenes containing a gem-dimethylcyclopropane subunit: an intriguing source of PKC modulators. Nat Prod Rep 31:940–952
Story EN, Kopec RE, Schwartz SJ, Harris GK (2010) An update on the health effects of tomato lycopene. Annu Rev Food Sci Technol 1:189–210
Buyuklu M, Kandemir FM, Ozkaraca M, Set T, Bakirci EM, Topal E, Ileriturk M, Turkmen K (2015) Benefical effects of lycopene against contrast medium-induced oxidative stress, inflammation, autophagy, and apoptosis in rat kidney. Hum Exp Toxicol 34:487–496
Achika JI, Ndukwe GI, Ayo RG (2016) Isolation, characterization and antimicrobial activity of 3 [beta], 22E-stigmasta-5, 22-dien-3-ol from the aerial part of Aeschynomene uniflora E. Mey. Br J Pharm Res 11:1–8
Bano M, P Barot K, Miftah Ahmed S, Nikolova S, Ivanov I, D Ghate M (2013) Benzopyran derivatives as cardio-selective ATP-sensitive potassium channel openers: a review. Mini Rev Med Chem 13:1744–1760.
Tsutsumi YM, Tsutsumi R, Mawatari K, Nakaya Y, Kinoshita M, Tanaka K, Oshita S (2011) Compound K, a metabolite of ginsenosides, induces cardiac protection mediated nitric oxide via Akt/PI3K pathway. Life Sci 88:725–729
Chen S, Yong T, Zhang Y, Su J, Jiao C, Xie Y (2017) Anti-tumor and anti-angiogenic ergosterols from Ganoderma lucidum. Front Chem 5:85
Abubacker MN, Devi PK (2014) In vitro antifungal potentials of bioactive compound oleic acid, 3-(octadecyloxy) propyl ester isolated from Lepidagathis cristata Willd.(Acanthaceae) inflorescence. Asian Pac J Trop Med 7:S190–S193
Saeed NM, El-Demerdash E, Abdel-Rahman HM, Algandaby MM, Al-Abbasi FA, Abdel-Naim AB (2012) Anti-inflammatory activity of methyl palmitate and ethyl palmitate in different experimental rat models. Toxicol Appl Pharmacol 264:84–93
Mariya V, Ravindran VS (2016) Anti-human pathogenic potential and compositional studies on the extract of Seastar, Protoreaster lincki (Blainville, 1830) collected from Tuticorin, Southeast Coast, India. Indian J Geo-marine Sci 44:147–154
Sakaguchi K, Morita I, Murota S (1994) Eicosapentaenoic acid inhibits bone loss due to ovariectomy in rats. Prostaglandins, Leukot Essent Fat Acids 50:81–84
Pakkirisamy M, Kalakandan SK, Ravichandran K (2017) Phytochemical screening, GC-MS, FT-IR analysis of methanolic extract of Curcuma caxia Roxb (Black Turmeric). Pharmacogn J 9:952–956
Horrocks LA, Yeo YK (1999) Health benefits of docosahexaenoic acid (DHA). Pharmacol Res 40:211–225
Munro DD, Robinson TWE, du Vivier AWP, France DM, Clayton R, Sparkes CG (1977) Betamethasone valerate ointment compared with fluocinonide FAPG: use in the treatment of psoriasis and eczema. Arch Dermatol 113:599–601
Seanego CT, Ndip RN (2012) Identification and antibacterial evaluation of bioactive compounds from Garcinia kola (Heckel) seeds. Molecules 17:6569–6584
Adeoye-Isijola MO, Olajuyigbe OO, Jonathan SG, Coopoosamy RM (2018) Bioactive compounds in ethanol extract of Lentinus squarrosulus Mont-a Nigerian medicinal macrofungus. African J Tradit Complement Altern Med 15:42–50
Sorg O, Antille C, Kaya G, Saurat J-H (2006) Retinoids in cosmeceuticals. Dermatol Ther 19:289–296
Gnanavel V, Saral AM (2013) GC-MS analysis of petroleum ether and ethanol leaf extracts from Abrus precatorius Linn. Int J Pharma Bio Sci 4:37–44
Hwang S-L, Shih P-H, Yen G-C (2012) Neuroprotective effects of citrus flavonoids. J Agric Food Chem 60:877–885
Cahoon LB, Halkides CJ, Song B, Williams CM, Dubay GR, Fries A, Farmer J, Fridrich W, Brookshire C (2012) Swine waste as a source of natural products: a carotenoid antioxidant. Agric Sci 3:806
Zayed MZ, Wu A, Sallam SM (2018) Comparative phytochemical constituents of Leucaena leucocephala (Lam.) leaves, fruits, stem barks, and wood branches grown in Egypt using GC-MS method coupled with multivariate statistical approaches. BioResources 14:996–1013
Rengarajan T, Rajendran P, Nandakumar N, Balasubramanian MP, Nishigaki I (2013) Cancer preventive efficacy of marine carotenoid fucoxanthin: cell cycle arrest and apoptosis. Nutrients 5:4978–4989
Fakhri S, Abbaszadeh F, Dargahi L, Jorjani M (2018) Astaxanthin: a mechanistic review on its biological activities and health benefits. Pharmacol Res 136:1–20
Syed SN, Rizvi W, Kumar A, Khan AA, Moin S, Ahsan A (2014) Antioxidant and hepatoprotective activity of ethanol extract of Valeriana wallichii in CCL4 treated rats. Br J Pharm Res 4:1004–1013
Umaru IJ, Badruddin FA, Umaru HA (2019) Phytochemical screening of essential oils and antibacterial activity and antioxidant properties of Barringtonia asiatica (L) leaf extract. Biochem Res Int 2019:1–6
Satue-Gracia MT, Heinonen M, Frankel EN (1997) Antioxidant activity of anthocyanin in LDL and lecithin liposome systems. J Agric Food Chem 45:3362–3367
Hazafa A, Rehman KU, Jahan N, Jabeen Z (2020) The role of polyphenol (flavonoids) compounds in the treatment of cancer cells. Nutr Cancer. 72(3):386–397
Montoro P, Braca A, Pizza C, De Tommasi N (2005) Structure-antioxidant activity relationships of flavonoids isolated from different plant species. Food Chem 92:349–355
Tungmunnithum D, Thongboonyou A, Pholboon A, Yangsabai A (2018) Flavonoids and other phenolic compounds from medicinal plants for pharmaceutical and medical aspects: an overview. Medicines 5:93–108
Ren Q, Chen J, Ding Y, Cheng J, Yang S, Ding Z, Dai Q, Ding Z (2019) In vitro antioxidant and immunostimulating activities of polysaccharides from Ginkgo biloba leaves. Int J Biol Macromol 124:972–980
Krishnaiah D, Sarbatly R, Nithyanandam R (2011) A review of the antioxidant potential of medicinal plant species. Food Bioprod Process 89:217–233
Khan RA, Khan MR, Sahreen S, Ahmed M (2012) Assessment of flavonoids contents and in vitro antioxidant activity of Launaea procumbens. Chem Cent J 6:43
Abdille MH, Singh RP, Jayaprakasha GK, Jena BS (2005) Antioxidant activity of the extracts from Dillenia indica fruits. Food Chem 90:891–896
Van Tonder A, Joubert AM, Cromarty AD (2015) Limitations of the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-2H-tetrazolium bromide (MTT) assay when compared to three commonly used cell enumeration assays. BMC Res Notes 8:47–56
Khan AA, Alanazi AM, Jabeen M, Chauhan A, Abdelhameed AS (2013) Design, synthesis and in vitro anticancer evaluation of a stearic acid-based ester conjugate. Anticancer Res 33:2517–2524
Ikeda Y, Tsuji S, Satoh A, Ishikura M, Shirasawa T, Shimizu T (2008) Protective effects of astaxanthin on 6-hydroxydopamine-induced apoptosis in human neuroblastoma SH-SY5Y cells. J Neurochem 107:1730–1740
Nagendraprabhu P, Sudhandiran G (2011) Astaxanthin inhibits tumor invasion by decreasing extracellular matrix production and induces apoptosis in experimental rat colon carcinogenesis by modulating the expressions of ERK-2, NFkB and COX-2. Invest New Drugs 29:207–224
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Ethics approval and consent to participate
Consent for publication
The authors declare no competing interests.
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
About this article
Cite this article
Diab, T.A., Donia, T.K. & Saad-Allah, K.M. Characterization, antioxidant, and cytotoxic effects of some Egyptian wild plant extracts. Beni-Suef Univ J Basic Appl Sci 10, 13 (2021). https://doi.org/10.1186/s43088-021-00103-0
- Egyptian plants
- Antitumor activity
- Antioxidant activity