**7. Biological activities of doum fruit extracts**

#### **7.1. Antioxidant activity of doum fruit extracts**

Doum is one of the commonly consumed traditional beverages in Egypt and is rich in polyphenolic compounds. Several studies have recorded that doum fruit extracts contain high amount of flavonoids, phenols and used as antioxidant and antibacterial activities (**Table 1**), which can alleviate the adverse effects of oxidative stress and prevent diseases caused by pathogenic bacteria [16]. It is well-known that plant phenolic compounds are highly effective free radical scavengers (**Figure 6**). Phenolic compounds antioxidant activity is associated with the presence of functional groups in the ring and the annular structure of the molecule, conjugated double bonds [42]. The antioxidant activity increased with the increase in concentration and the consumption of doum plant which would exert several beneficial effects by the value of its antioxidant and antimicrobial activities [27].

2,2-Diphenyl-1-Picrylhydrazyl (DPPH) is a free radical that received an electron or hydrogen radical and become a stable diamagnetic molecule [43]. DPPH was determined by the decrease in its absorbance at 517 nm, which was induced by antioxidants. The ability of hydrogen donating in the polyphenolic compounds in the doum fruit extracts helps in the scavenging ability of DPPH. The antioxidant activity measured from doum extracts was 343.4 μ moles trolox equivalents/g DW in hydrophilic extract and 42.67 μ moles trolox equivalents/g DW in lipophilic extract when using DPPH [29]. In addition, the IC50 values of doum extracts varied from 107.6 to 172.7 μg/ml [16]. These results are lower than the results reported by Abou–Elalla [44] who found that the aqueous doum extract exhibited 50% antioxidant activity (IC50) at the concentration of 1000 μg/ml, also 1500 μg/ml extract exhibited 80% antioxidant activity. Also, the aqueous ethanolic extract of doum leaves appeared to be a potent scavenger of reactive oxygen species [41]. Strong correlation between total phenolics content and total Biological Activities of the Doum Palm (*Hyphaene thebaica* L.) Extract and Its Bioactive… http://dx.doi.org/10.5772/intechopen.74772 57


**Table 1.** Antioxidant activity/ IC50 Inhibition values of doum part by different methods.

**7. Biological activities of doum fruit extracts**

**Figure 5.** Chemical structures of doum leave phenolic compound.

56 Antioxidants in Foods and Its Applications

Doum is one of the commonly consumed traditional beverages in Egypt and is rich in polyphenolic compounds. Several studies have recorded that doum fruit extracts contain high amount of flavonoids, phenols and used as antioxidant and antibacterial activities (**Table 1**), which can alleviate the adverse effects of oxidative stress and prevent diseases caused by pathogenic bacteria [16]. It is well-known that plant phenolic compounds are highly effective free radical scavengers (**Figure 6**). Phenolic compounds antioxidant activity is associated with the presence of functional groups in the ring and the annular structure of the molecule, conjugated double bonds [42]. The antioxidant activity increased with the increase in concentration and the consumption of doum plant which would exert several beneficial effects by the value

2,2-Diphenyl-1-Picrylhydrazyl (DPPH) is a free radical that received an electron or hydrogen radical and become a stable diamagnetic molecule [43]. DPPH was determined by the decrease in its absorbance at 517 nm, which was induced by antioxidants. The ability of hydrogen donating in the polyphenolic compounds in the doum fruit extracts helps in the scavenging ability of DPPH. The antioxidant activity measured from doum extracts was 343.4 μ moles trolox equivalents/g DW in hydrophilic extract and 42.67 μ moles trolox equivalents/g DW in lipophilic extract when using DPPH [29]. In addition, the IC50 values of doum extracts varied from 107.6 to 172.7 μg/ml [16]. These results are lower than the results reported by Abou–Elalla [44] who found that the aqueous doum extract exhibited 50% antioxidant activity (IC50) at the concentration of 1000 μg/ml, also 1500 μg/ml extract exhibited 80% antioxidant activity. Also, the aqueous ethanolic extract of doum leaves appeared to be a potent scavenger of reactive oxygen species [41]. Strong correlation between total phenolics content and total

**7.1. Antioxidant activity of doum fruit extracts**

of its antioxidant and antimicrobial activities [27].

**Figure 6.** The scheme of factors involved in the formation of free radicals and a cellular response to reactive oxygen species (ROS). The red arrow and the text in red emphasize the importance of phenolic compounds, other reactive oxygen species (ROS). The red arrow and the text in red emphasize the importance of phenolic compounds, other antioxidants and the relationship between them. The sun signifies protection of other antioxidants by phenolic compounds.

antioxidant activity reported in many studies concluded the significant role that total phenols can play in antioxidant activity [29].

major role in preventing the formation of free radicals, which are responsible for many harmful oxidative processes [50]. Antioxidants may be synthetic or of natural source [51]. Antioxidants play an important role in the later stages of cancer development. The methanol extract of *H. thebaica* bark showed high cytotoxicity against human cancer cells and free radical scavenging activities, but showed no cytotoxic effect on human normal immortalized fibroblast cells (BJ- 1) [52]. *H. thebaica* extract showed cytotoxicity against A549 (lung carcinoma) and MCF-7 (breast adenocarcinoma) (87% and 89% respectively). Others reported that the fruit extract of *H. thebaica* had antioxidant and anticancer activities against acute myeloid leukemia [43]. It found that the incubation of tumor cells with doum extract significantly reduced the viability of these cells and the dead cells were significantly increased with high extract concentration. At concentration of 2 μg/ml, the extract reduced the viability from 98 to 83% (17% death). The dead cells produced by extract reached to 50% by 3 μg/ml when compared to control (2% death). Also, doum extract reduced the viability from 98 to 60% (61% death at 4 μg/ml and the dead cells reached to 92% dead by 8 μg/ml). This anticancer activity may be due to the antioxidant activity of doum extract. This is due to the substantial amount of their water-soluble phenolic compounds [6]. Plants extract which combines antioxidant and anticancer activities and at the same time safe to healthy cells is a promising cancer chemopreventive candidate.

Biological Activities of the Doum Palm (*Hyphaene thebaica* L.) Extract and Its Bioactive…

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59

The logic behind this is that the antioxidant will reduce, if not prevent, the DNA mutations and adducts caused by cytosolic free radicals and consequently prevent the initiation of cancer through induction of mutations. The anticancer activity will be useful in early eliminating any newly formed neoplastic cells that are not clinically detectable. However, these cancer cytotoxic agents should be with minor or no side effects as they are planned to be used for

Ulcerative colitis (UC) and Crohn's disease (CD) are two major categories of inflammatory bowel diseases (IBDs). Familiar drugs that are administrated for the management of IBD include glucocorticoids and sulfasalazine. Antibiotics, monoclonal antibodies (Infliximab) and immunosuppressants are also sometimes used for difficult disease conditions [53]. These medicinal agents have side effects, and they could not suitably cure IBD patients [54]. In many studies, it has been reported that antioxidants show useful effects in experimental colitis [55]. The effect of various herbal drugs on experimental models of inflammatory bowel diseases (IBD) has been reported earlier with the antioxidant potential as the main mechanism of action against IBD [56]. As the plant *H. thebaica* is thought to possess anti-inflammatory and antioxidant properties, proving its role in the management of experimentally induced IBD [27]. It showed significant amelioration of experimentally induced IBD, which may be attributed to its antioxidant and anti-inflammatory properties [57]. The previous studies found that the weight and volume of contents of granuloma in inflammation were decreased after treatment with doum extract. This may be due to the presence of flavonoids, coumarins and saponins in doum extract which has anti-proliferative activity [58]. Therefore, this might be its probable mechanism of anti-inflammatory action. Also, flavonoids and coumarin derivatives have been reported as protective products to prevent and treat intestinal inflammatory processes induced by different chemical indictors of experimental colitis [59]. In addition, diet supplementation

prolonged time preventing cancer formation [52].

**7.3. Anti-inflammatory activity of doum fruit extracts**

Iron is known as an essential transition metal element in the human body for the activity of many enzymes and for some important proteins participated in cellular respiration, O<sup>2</sup> transport, and redox reactions. However, because its transition metal, it contains one or more unpaired electrons that enable them to share in one-electron transfer reactions. Hence, its potent catalysts of autoxidation reactions, such as involvement in the production of OH− from H2 O2 in the Fenton reaction and in the decay of alkyl peroxides to alkoxyl and hydroxyl radicals [45]. Because of this property, transition metal chelation to shape low redox potential complexes is significant antioxidant property and measuring chelation of iron (II) is one method for estimating this property [46]. The reaction is based on the relationship of an antioxidant toward iron (II) in relation to ferrozine, the assay is affected by both concentration of antioxidant and binding constant and thus only powerful iron antioxidant chelator is detected. With this assay, many plant phenolic compounds have been described as antioxidants due to their chelating ability to iron ions. *H. thebaica* fruit has antioxidant activity of 28.93 ± 0.23% and 31.91 ± 0.14% for methanol and aqueous extract respectively [47]. The extracts of doum fruits showed an antioxidant potential, and this is due to the substantial amount of their water-soluble phenolic content [6]. The percentage of metal scavenging capacity at 200 μg/ ml of tested methanol extracts *H. thebaica* and was found to be 24.3%. The antioxidant activity increased when extract concentration increased [27].

It displayed the Fe2+ chelating effect in a concentration-dependent manner. The antioxidant activity measured from doum extract was 13.57 μmoles trolox equivalents/g DW in hydrophilic extract and 7.69 μmoles trolox equivalents/g DW in lipophilic extract when using FRAP assay [29]. These results are in agreement with previous study, who found that doum fruit contained contain iron (II) chelating activity [6].

Superoxide radical is harmful to the body because it is a portent of the hydroxyl radical in the Fenton reaction and is the part of lipid peroxidation as an allylic hydrogen abstractor. Phenazine methosulphate/ß-NADH/nitro blue tetrazolium (PMS/NADH/NTB) system is used to determine superoxide radical [6]. Again, an antioxidant activity can come about by antioxidant donation of hydrogen or electron to superoxide or by direct reaction with it. Using this assay, doum fruit was found a very poor activity toward superoxide; it contains 0.02 mmol gallic acid equivalents/g extract. In addition, the significant inhibition percentage of superoxide generation was shown at 300 μg/ml concentration of *H. thebaica* as 63.22% [27]. The Doum extract is found to be an efficient scavenger of superoxide radicals generated in a PMS-NADH system in vitro and its activity is comparable to that of quercetin.

#### **7.2. Anticancer activity of doum fruit extracts**

Free radicals can react with biomolecules, causing extensive damage to DNA, protein, and lipid, which are considered to be related to aging, degenerative diseases of aging, cancer [48, 49]. Antioxidants play an important role in the later stages of cancer development. The oxidative stress is defined as the imbalance between oxidants and antioxidants in favor of the oxidants potentially leading to damage in human cells. Physiologically, antioxidants play a major role in preventing the formation of free radicals, which are responsible for many harmful oxidative processes [50]. Antioxidants may be synthetic or of natural source [51]. Antioxidants play an important role in the later stages of cancer development. The methanol extract of *H. thebaica* bark showed high cytotoxicity against human cancer cells and free radical scavenging activities, but showed no cytotoxic effect on human normal immortalized fibroblast cells (BJ- 1) [52]. *H. thebaica* extract showed cytotoxicity against A549 (lung carcinoma) and MCF-7 (breast adenocarcinoma) (87% and 89% respectively). Others reported that the fruit extract of *H. thebaica* had antioxidant and anticancer activities against acute myeloid leukemia [43]. It found that the incubation of tumor cells with doum extract significantly reduced the viability of these cells and the dead cells were significantly increased with high extract concentration. At concentration of 2 μg/ml, the extract reduced the viability from 98 to 83% (17% death). The dead cells produced by extract reached to 50% by 3 μg/ml when compared to control (2% death). Also, doum extract reduced the viability from 98 to 60% (61% death at 4 μg/ml and the dead cells reached to 92% dead by 8 μg/ml). This anticancer activity may be due to the antioxidant activity of doum extract. This is due to the substantial amount of their water-soluble phenolic compounds [6]. Plants extract which combines antioxidant and anticancer activities and at the same time safe to healthy cells is a promising cancer chemopreventive candidate.

The logic behind this is that the antioxidant will reduce, if not prevent, the DNA mutations and adducts caused by cytosolic free radicals and consequently prevent the initiation of cancer through induction of mutations. The anticancer activity will be useful in early eliminating any newly formed neoplastic cells that are not clinically detectable. However, these cancer cytotoxic agents should be with minor or no side effects as they are planned to be used for prolonged time preventing cancer formation [52].

#### **7.3. Anti-inflammatory activity of doum fruit extracts**

antioxidant activity reported in many studies concluded the significant role that total phenols

Iron is known as an essential transition metal element in the human body for the activity of many enzymes and for some important proteins participated in cellular respiration, O<sup>2</sup> transport, and redox reactions. However, because its transition metal, it contains one or more unpaired electrons that enable them to share in one-electron transfer reactions. Hence, its potent catalysts of autoxidation reactions, such as involvement in the production of OH−

 in the Fenton reaction and in the decay of alkyl peroxides to alkoxyl and hydroxyl radicals [45]. Because of this property, transition metal chelation to shape low redox potential complexes is significant antioxidant property and measuring chelation of iron (II) is one method for estimating this property [46]. The reaction is based on the relationship of an antioxidant toward iron (II) in relation to ferrozine, the assay is affected by both concentration of antioxidant and binding constant and thus only powerful iron antioxidant chelator is detected. With this assay, many plant phenolic compounds have been described as antioxidants due to their chelating ability to iron ions. *H. thebaica* fruit has antioxidant activity of 28.93 ± 0.23% and 31.91 ± 0.14% for methanol and aqueous extract respectively [47]. The extracts of doum fruits showed an antioxidant potential, and this is due to the substantial amount of their water-soluble phenolic content [6]. The percentage of metal scavenging capacity at 200 μg/ ml of tested methanol extracts *H. thebaica* and was found to be 24.3%. The antioxidant activity

It displayed the Fe2+ chelating effect in a concentration-dependent manner. The antioxidant activity measured from doum extract was 13.57 μmoles trolox equivalents/g DW in hydrophilic extract and 7.69 μmoles trolox equivalents/g DW in lipophilic extract when using FRAP assay [29]. These results are in agreement with previous study, who found that doum fruit

Superoxide radical is harmful to the body because it is a portent of the hydroxyl radical in the Fenton reaction and is the part of lipid peroxidation as an allylic hydrogen abstractor. Phenazine methosulphate/ß-NADH/nitro blue tetrazolium (PMS/NADH/NTB) system is used to determine superoxide radical [6]. Again, an antioxidant activity can come about by antioxidant donation of hydrogen or electron to superoxide or by direct reaction with it. Using this assay, doum fruit was found a very poor activity toward superoxide; it contains 0.02 mmol gallic acid equivalents/g extract. In addition, the significant inhibition percentage of superoxide generation was shown at 300 μg/ml concentration of *H. thebaica* as 63.22% [27]. The Doum extract is found to be an efficient scavenger of superoxide radicals generated in a

Free radicals can react with biomolecules, causing extensive damage to DNA, protein, and lipid, which are considered to be related to aging, degenerative diseases of aging, cancer [48, 49]. Antioxidants play an important role in the later stages of cancer development. The oxidative stress is defined as the imbalance between oxidants and antioxidants in favor of the oxidants potentially leading to damage in human cells. Physiologically, antioxidants play a

PMS-NADH system in vitro and its activity is comparable to that of quercetin.

from

can play in antioxidant activity [29].

58 Antioxidants in Foods and Its Applications

increased when extract concentration increased [27].

contained contain iron (II) chelating activity [6].

**7.2. Anticancer activity of doum fruit extracts**

H2 O2

> Ulcerative colitis (UC) and Crohn's disease (CD) are two major categories of inflammatory bowel diseases (IBDs). Familiar drugs that are administrated for the management of IBD include glucocorticoids and sulfasalazine. Antibiotics, monoclonal antibodies (Infliximab) and immunosuppressants are also sometimes used for difficult disease conditions [53]. These medicinal agents have side effects, and they could not suitably cure IBD patients [54]. In many studies, it has been reported that antioxidants show useful effects in experimental colitis [55]. The effect of various herbal drugs on experimental models of inflammatory bowel diseases (IBD) has been reported earlier with the antioxidant potential as the main mechanism of action against IBD [56]. As the plant *H. thebaica* is thought to possess anti-inflammatory and antioxidant properties, proving its role in the management of experimentally induced IBD [27]. It showed significant amelioration of experimentally induced IBD, which may be attributed to its antioxidant and anti-inflammatory properties [57]. The previous studies found that the weight and volume of contents of granuloma in inflammation were decreased after treatment with doum extract. This may be due to the presence of flavonoids, coumarins and saponins in doum extract which has anti-proliferative activity [58]. Therefore, this might be its probable mechanism of anti-inflammatory action. Also, flavonoids and coumarin derivatives have been reported as protective products to prevent and treat intestinal inflammatory processes induced by different chemical indictors of experimental colitis [59]. In addition, diet supplementation

with doum has a promising anti-inflammatory influence on attenuating the complications associated with the renal dysfunction. Moreover, anti-inflammatory status of animals injected with cyclo sporine and supplemented with doum showed a significant amelioration in the kidney functions as compared to animals injected with the cyclosporine only [60]. The antiinflammatory activity of doum was possibly due to its saponin content which acts against the oxidative damage and suppresses the serum transforming growth factor-ß1 (TGF-beta1) expression [61]. Therefore, doum administration declines the oxidative damage and the renal interstitial fibrosis in rats [60]. The significant increase in white blood cells caused by crude mesocarp extract of *H. thebaica* could be due to stimulation of bone marrow stem cells to produce these cells, which is an indication of immune—modulatory effect as was observed by other researchers exhibited by some plants [62]. The presence of phytochemicals such as glycosides and reducing sugars could be the reason for the leukocytosis [63]. Flavonoids protect both the hematopoietic committed stem cells and the formed blood cells from the attack of the reactive free radicals hence improving leucocytic production [64]. In *H. thebaica*, flavonoid conjugates, oxygenated fatty acids, and sphingolipids enriched in fruits are likely to mediate for its anti-inflammatory effect [65, 66].

inhibition of the synthesis of cell walls and cell membranes, nucleic acids and proteins, as well

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61

*Hyphaene thebaica*, a well-known plant for its antioxidant, anticancer and anti-Inflammatory potential because of its phenolic and flavonoid content was explored for its antimicrobial potential against various Gram-positive and Gram-negative bacteria and fungal pathogens. This chapter evidently reveals that the doum (leaf and fruit) extracts are effective antimicrobial and pharmacological agents. Further detailed study on its mechanism and safety profile may develop them as good candidates for food preservation or functional foods, as well as for

The authors would like to show appreciation to Faculty of Agriculture, Cairo University, Department of Biochemistry and Faculty of Education, Ain Shams University, Department of Biological and Geological Sciences for continuing cooperation to support research that pro-

, Hany N. Yousef3

1 Faculty of Agriculture, Biochemistry Department, Cairo University, Giza, Cairo, Egypt

3 Faculty of Education, Animal Physiology Department, Ain Shams University, Cairo, Egypt

[1] Orwa C, Mutua A, Kindt R, Jamnadass R, Anthony S. Agro-Forest tree data base: A tree reference and selection version 4.0; 2009. Available from: http://www.worldagroforestry.

[2] Auwal MS, Shuaibu A, Lawan FA, Sanda KA, Njobdi AB, Ibrahim A, et al. Effect of crude mesocarp extract of *Hyphaene thebaica* Doum palm on white blood cells and differential leucocytic count in wistar albino rats. Journal of Medical Sciences. 2012;**12**:207-213

2 Faculty of Education, Biological and Geological Sciences Department, Ain Shams

and Eman M. Fawzi2

vided facilities necessary to accomplish the most wanted objectives of research.

\*, Heba I. Mohamed<sup>2</sup>

\*Address all correspondence to: helbeltagi@agr.cu.edu.eg

org/sites/treedbs/treedatabases.asp

as the inhibition of the metabolism of nuclide acids [73].

pharmaceutical and natural plant-based products.

**8. Conclusion**

**Acknowledgements**

**Author details**

Hossam S. El-Beltagi<sup>1</sup>

University, Cairo, Egypt

**References**

Doum extracts treatments inhibited the activity of cyclooxygenase (COX-1), an enzyme known to be involved in inflammation [33].

#### **7.4. Antimicrobial activity of doum fruit extracts**

Methanol and aqueous extracts of doum fruit showed higherantibacterial activity against Gram-positive bacteria and Gram-positive bacteria except for *Listeria monocytogenes*, where only a slight inhibition was observed [27]. Moreover, the ethyl acetate extract of doum fruit was active against five pathogenic bacteria, *Staphylococcus aureus*, *Escherichia coli*, *Bacellussubtilis*, *Pseudomonas aeruginosa* and *Klebsiella pneumonia* while methanol extract was active against *Pseudomonas aeruginosa* and *Klebsiella pneumonia*. Penicillium sp. growth was slightly affected by high concentration of methanolic extract [67]. *H. thebaica* fruit extracts reduced the growth of Erwiniacarotovora and produced inhibition zones up to 38 mm in diameter [68]. All doum extracts showed strong antibacterial activity against *Staphylococcus aureus* and Salmonella typhi, while methanol/ultrasonic (MU) extract inhibited the growth of all pathogenic bacteria used in the study. However, all doum fruit extracts demonstrated no antibacterial activity against *E. coli* colonies except the methanol/ultrasonic (MU) extract, which had slight activity [16]. The antibacterial activities against both Gram-positive and Gram-negative bacteria may indicate the presence of broad spectra antibiotic compounds or simply metabolic toxins in plant extracts [69]. Doum fruits showed antimicrobial and antihypertensive activities, and these activities were attributed to the presence of flavonoids [70]. The mechanism of polyphenol toxicity against microbes may be related to inhibition of hydrolytic enzymes (proteases) or other interactions that inactivate microbial adhesins, cell envelope transport proteins, and non-specific interactions with carbohydrates [71]. Also, the methanolic extract of *H. thebaica* showed stronger antifungal and anti-yeast activities than aqueous extracts [27]. Similar results were observed in previous studies, which showed that polar solvent extract of H. Tobacco has high antifungal activity against a wide range of fungal isolates, including *Aspergillus niger*, *Microsporum gypseum*, *Trichlorophyton rubrum*, *Mucor* sp., *Fusarium solani* and *Candida albicans* [72]. Antimicrobial activity may involve complex mechanisms, like the inhibition of the synthesis of cell walls and cell membranes, nucleic acids and proteins, as well as the inhibition of the metabolism of nuclide acids [73].
