PROTEINS
Antiviral Activity
Rotaviruses are the most frequent cause of nonbacte- rial gastroenteritis in infants or calves in most parts of the world. In Egypt, the Bedouins use camel milk to treat diarrhea (personal observation). Camel milk immunoglobulin (IgG) and secretory immunoglobu- lin A (sIgA) were purifi ed and their neutralization activity against bovine (El - Agamy et al. 1992 ) or human (El - Agamy 2000b ) rotavirus was studied.
Individual camel ( Camelus dromedarius ) colostrum and normal milk samples were tested for the pres- ence of antibodies to rota - and coronaviruses. All samples were negative for anticoronavirus antibod- ies; while some of colostrum and milk samples had specifi c antibodies to rotavirus. The antirotavirus activity, i.e., antibody titer in colostrum, was strong due to IgG, while sIgA in normal milk was high (Fig. 6.3 A and B). This indicates that raw camel milk is considered a strong viral inhibitor to human rotavirus. Meanwhile, the high titer of sIgA against rotavirus refl ects that she - camel mammary glands are able to synthesize a high concentration of such
type of immunoglobulin as a defense factor. These fi ndings may explain the reason for use of camel milk as a remedy to treat diarrhea by camel herds- men (El - Agamy 1983 ).
The antiviral properties of freshly prepared or conserved Shubat, a national drink of fermented camel milk in Kazakhstan, were studied (Chuvakova et al. 2000 ). The results showed that Shubat is characterized by virucidal and virus - inhibiting properties against ortho - and paramyxovi- ruses, and these properties were not affected by shelf life. The antiviral activity of Shubat is sug- gested to be due to the presence of sialic conjugates and metabolic products of lactic acid bacteria and yeasts.
Antibacterial Activity Lysozyme
The inhibitory effects of camel milk lysozyme in 200 individual milk samples on pathogenic bacteria were examined (Barbour et al. 1984 ). Results showed that percentages of inhibition were 7.5, 4.0, 2.0, and 1.0% for Clostridium perfringens , Staphylococcus aureus, Shigella dysenteriae , and Salmonella typhimurium , respectively; however, none of the whole samples inhibited Bacillus cereus or Escherichia coli .
The inhibition effect of camel milk lysozyme was also studied comparing with egg white lysozyme and bovine milk lysozyme against some strains of bacteria (El - Agamy 1989 ). Results revealed that camel milk lysozyme had a higher lysis value toward Salmonella typhimurium compared with other lysozymes. The results obtained by disc assay tech- nique indicated that the clearance zone values were 22.2, 20.2, and 0.0 mm for camel, egg white, and bovine milk lysozyme, respectively. Camel milk lysozyme had no effect on Lactococcus lactis subsp.
cremoris ; however, the strain was highly affected by bovine milk lysozyme. All lysozymes were ineffec- tive toward Escherichia coli and Staphylococcus aureus .
It has been found that lysozyme increases the antibacterial activity of lactoferrin. Commercial preparations of lysozyme are an interesting alterna- tive to nitrate as an antisporulating agent, preventing the growth of Clostridium tyrobutiricum in cheese (Stepaniak 2004 ).
Figure 6.3. A. Antirotavirus activity in camel - colostral whey expressed as antibody titer (A) or specifi c activity (B) (El - Agamy 2000b ). B. Antirotavirus activity in camel normal - milk whey expressed as antibody titer (A) or specifi c activity (B) (El - Agamy 2000b ).
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Lactoferrin
The inhibition effect of lactoferrin depends mainly on iron requirements of microorganisms. For example, E. coli is much more sensitive than lactic acid bacteria (Reiter 1985 ). The inhibition effect of camel and bovine milk lactoferrins against some strains of bacteria was studied (El - Agamy 1989 ).
Both types of lactoferrins were effective against Sal- monella typhimurium , and the clearance inhibition zones were 18.2 and 17.4 mm for camel and bovine milk lactoferrins, respectively. Neither camel nor bovine milk lactoferrin had a lysis effect toward E.
coli and Staphylococcus aureus .
Taking into account that the inhibition rate of camel lactoferrin against such microorganisms was detected in synthetic media, this effect is probably different when liquid media such as milk are used, because it was reported that citrate ions can coun- teract the bacteriostatic activity of lactoferrin, i.e., compete for iron, unless the bicarbonate concentra- tion is high (Reiter 1985 ). Therefore, it can be expected that lactoferrin activity in camel milk will be higher due to the lower concentration of citrate ions (El - Agamy 1983 ). It can be assumed that the inhibition effect of lactoferrin in camel milk, when ingested by the nomads in the desert, is due to two main factors: 1) the low content of citrate in camel milk and 2) the high bicarbonate concentration in the intestinal fl uid, where bicarbonate is the main buffer (Reiter 1985 ). These two factors will provide the proper conditions for lactoferrin to bind iron and inhibit sensitive microorganisms such as E. coli . The Lactoperoxidase System ( LPS )
Camel milk lactoperoxidase was purifi ed and its inhibition activity against lactic acid bacteria and some strains of pathogenic bacteria was studied (El - Agamy et al. 1992 ). The LP system had a bacterio- static effect toward both Lactococcus lactis and Staphylococcus aureus ; however, it was bactericidal for E. coli 0157:H7 and Salmonella typhimurium . The destructive effect of camel LP system on the cell walls of these bacterial strains was recorded (Fig. 6.4 ).
Medicinal Properties of Camel Milk Camel milk in raw state and its fermented products are used as therapeutic agents to treat stomach
ulcers, liver disorders, diarrhea, constipation, and wounds, as well as to enhance female ovaries for ovulation (personal observations). Camel milk is also given to children suffering from biliary atresia and postpartum respiratory insuffi ciency and kept alive until a liver transplant could be performed and lungs are developed (Yagil 1987 ). Fermented camel milk Shubat is used as a therapy for treating tuber- culosis in different countries, India (Mal et al. 2000 ), Libya (Alwan and Tarhuni 2000 ), and Kazakhstan (Puzyrevskaya et al. 2000 ). Treatment of chronic diseases of the gastrointestinal tract using camel milk and Shubat was also reported (Djangabilov et al. 2000 ). Camel milk is used for chronic hepatitis, spleen infl ammation (personal observations). Similar remarks were recorded in the former USSR (Sharmanov et al. 1978 ). It was reported that patients suffering from chronic hepatitis have improved liver functions after drinking camel milk. Early reports showed that camel milk is successfully used for sta- bilization of juvenile diabetes (Yagil 1987 ). It was found that one of the camel milk proteins has many characteristics similar to insulin (Beg et al. 1986a ) and it does not form coagulum in an acidic environ- ment (Wangoh 1993 ). This lack of coagulum forma- tion allows the camel milk to pass rapidly through the stomach together with the specifi c insulinlike protein and remains available for absorption in the intestine. Breitling (2002) suggested that camel milk is having antidiabetic activity possibly because of insulinlike activity, regulatory and immunomodula- tory functions on β cells.
Other reports showed that camel milk supplemen- tation reduces the insulin requirement in type 1 dia- betic patients (Agrawal et al. 2003 ). Moreover, it has been found that after 1 year of treatment with camel milk as an adjunct to insulin therapy, it was found that camel milk improves long - term glycemic control and reduction in doses of insulin in patients with type 1 diabetes (Agrawal et al. 2005 ).
Recently in India, Agrawal et al. (2007) observed a low prevalence of diabetes in a community con- suming camel milk habitually. The prevalence of diabetes in a community (n = 501) was 0% versus 5.5% in a community not consuming camel milk (n = 529).The study concluded that the consumption of camel milk was statistically highly signifi cant as a protective factor for diabetes. In Africa, Egypt, Sudan, Kenya, and Somalia, there is a common belief among the herdsmen of camels, especially
those grazing on herbs, that if a man drinks camel milk he becomes strong, swift, and virile (personal observations).