The complex world of polysaccharides edited by Desiree Nedra Karunaratne

 

The Complex World of Polysaccharides 

 

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Figure 6.

 Staphylococcus bacteria (a), covered with chitosan (b)  

18. Analgesic activity 

Some investigators reported that chitin and chitosan induce analgesia. Allan in 1984 found 

that chitosan provide a cool and pleasant soothing effect when applied to open wounds. 

Ohshima et al in 1987, reported that chitin proved excellent pain relief in 83 out of 91 cases 

who received the agent topically over open wounds such as burns, skin abrasion, skin 

ulcers, skin graft areas and so on [134-135]. Minami in 1993 and Okamoto in 1993, reported 

that animals did not feel pain when their wounds were covered with chitin and chitosan 

[136-137].  

Chitin and chitosan have been found to reduce the inflammatory pain due to intraperitoneal 

administration of acetic acid in rats [138]. When the chitosan suspension was mixed with 

acetic acid, the amino groups in C2 the position were protonated to NH

3

 subsequently the 

particles resolved in the solution. Bradykinin is one of the main substances related to pain 

and the levels of this substance decrease in the presence of chitin and chitosan. Chitin 

absorbs Bradykinin more extensively than chitosan and this could be one of the main 

analgesic effect [138].  

19. Antitumor activity 

In some medical applications of chitin/chitosan, as antitumor compounds, for example, their 

degradation products are preferred, as they have a lower viscosity and a better solubility in 

water. The antitumor activity of chitin/chitosan is manifested by the stimulation of the 

immune system (production of lymphokines, including interleukins 1 and 2, stimulation of 

NK, etc.) [139-141]. Jeon and Kim in 2002, tested the antitumor activity of three kinds of 

COSs (high molecular weight ranging from 6.5 to 12 kDa – HMWCOS, medium molecular 

weight ranging from 1.5 to 5.5 kDa -MMWCOS, and low molecular weight ranging from 0.5 

to 1.4 kDa – LMWCOS) against Sarcoma 180 solid (S180) and Uterine cervix carcinoma No. 

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Is Chitosan a New Panacea? Areas of Application 

 

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14 (U14) [140]. The efficiency of tumor growth inhibition for both types of tumor cells in 

mice was best in the case of MMWCOS. There are many reports of S180 tumor cells being 

used for testing the antitumor activity of chitosan [141-142].  

Maeda and Kimura 2004, investigated the antitumour effect of three water-soluble low 

molecular weight chitosans (21 kDa, 46 kDa, 130 kDa) and various doses of 650 kDa chitosan 

in sarcoma 180-bearing mice. They found that LMWC (21 and 46 kDa) and also smaller 

oligosaccharides could activate the intestinal immune system of animals, thus preventing 

tumor growth. But no antitumor effect was observed after the oral administration of 

chitosan samples, even of low molecular weight (46 kDa). The same authors confirmed that 

high molecular weight chitosan (650 kDa) prevents the adverse reactions of some cancer 

chemotherapeutic drugs [141]. Qin et al. in 2002 also tested the antitumor activity of LMWC 

against sarcoma 180, but they came to the opposite conclusions [143]. They noted that oral 

administration of LMW chitosan decreases the weight of the tumour [139, 142], although 

administration by intraperitoneal injection led to a higher inhibitory rate [142]. It was 

reported the higher the MW of LMWC, the better the tumor inhibitory effect [139]. The 

introduction of acidic groups as a result of chitosan oxidation has the opposite effect, and an 

increase in MW decreases antitumor activity. Qin Cai-qin et al in 2002, prepared low 

molecular weight chitosans by oxidative degradation with H

2

O

2

. They found that carboxyllc 

contents increased with decrease in molecular weight (M~). They also found that the 

introduction of carboxylic group is advantage to water-solubility of chitosan, but more 

acidic groups decrease the function of amino groups of chitosan against sarcoma 180 tumor. 

There is a correlation between the activity and the molecular weights of the oxidized 

chitosans, and a maximum of inhibition was found around 4 100 [143]. The influence of 

LMWC and COS (including the pentamer, hexamer, and higher oligomers) on the growth 

inhibition of Ehrlich ascites tumor (EAT) cells and tumor induced neovascularization was 

investigated [144]. Based on experimental results concerning the inhibition of angiogenesis 

and the induction of apoptosis, it was confirmed that COSs seem to be more potent angio 

inhibitory and antitumor compounds. Wang et al. reported that chitin oligosaccharides (DP 

1-6) also reduced the number of K562 cells (human erythromyeloblastoid leukemia cell line) 

[145]. 

20. Chitosan applications  

20.1. Biomedical 

Potential applications of chitosan can only be exploited if its usable forms are properly 

developed and prepared. In solution and gel, it can be used as a bacteriostatic, fungistatic 

and coating agent. Gels and suspensions may play the role of carriers for slow release or 

controlled action of drugs, as an immobilising medium and an encapsulation material. Film 

and membranes are used in dialysis, contact lenses, dressings and the encapsulation of 

mammal cells, including cell cultures. Chitosan sponges are used in dressings, and to stop 

bleeding in mucous membranes. Chitosan fibres are used as resorbable sutures, non-wovens 

for dressings, and as drug carriers in the form of hollow fibres. 

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