Anti-inflammatory effects of chlorella in chronic and acute inflammation

Study Objectives

Inflammation is originally related to biological defenses against microorganisms, etc. However, inflammatory reactions that have become chronic are known to be involved in rheumatism, etc. We have elucidated in vitro possible anti-inflammatory effects of chlorella. (For details, please refer to "Investigation of pharmacological effects of chlorella powder" (reported at the 61st Meeting of the Japanese Society of Nutrition and Food Science). In this regard, we verified the anti-inflammatory effects of chlorella in using 2 animal models, including one with chronic inflammation in adjuvant-induced arthritis and the other with acute inflammation in the form of carrageenan-induced edema.

1．Adjuvant-induced arthritis model^*1

Method and experiments

Rats were assigned to the following 5 groups, and the degree of pedal volume increase induced by adjuvant was compared among groups given chlorella powder for 28 days and a group given anti-inflammatory drug. On the last day of the study, the degree of ankle destruction was assessed^*2 and serum cytokine 1L-1β^*3 levels were determined.

1)

Control group: Only an inflammatory agent was injected.

2)

Anti-inflammatory drug group: After injection of an inflammatory agent, oral administration of the anti-inflammatory drug dexamethasone was conducted once a day for 5 days.

3)

Chlorella 1 g/kg group: An inflammatory agent was injected*.

4)

Chlorella 0.5 g/kg group: An inflammatory agent was injected*.

*Chlorella powder was orally administered once a day for a total of 28 days from 7 days before to 21 days after the injection of an inflammatory agent.

5)

Normal group: No treatment

Results

Continuous ingestion of chlorella powder resulted in statistically significant inhibition of increase in pedal volume in the adjuvant-induced arthritis model, although the extent of inhibition was less than that with the anti-inflammatory drug (Fig. 1). Chlorella powder also tended to inhibit destruction of the ankle (Fig. 2) and increase in serum cytokine IL-1β level (Fig. 3), although the extent of inhibition was less than that with the anti-inflammatory drug. These findings suggested that continuous ingestion of chlorella powder could be effective in inhibiting the onset of inflammation.

2. Carrageenan-induced edema model^*4

Method of experiments

Rats were assigned to the following 4 groups, and degree of pedal volume increase induced by an inflammatory agent was compared among the groups given chlorella powder for 7 days and a group given an anti-inflammatory drug.

1)

Control group: Only an inflammatory agent was injected.

2)

Anti-inflammatory drug group: Single oral administration of the anti-inflammatory drug indometacin was conducted the day before injection of an inflammatory agent.

3)

Chlorella 1 g/kg group: An inflammatory agent was injected*.

4)

Chlorella 0.5 g/kg group: An inflammatory agent was injected*.

*Chlorella powder was orally administered once a day for 7 days before injection of an inflammatory agent.

Results

Continuous ingestion of chlorella powder tended to inhibit the increase in pedal volume in the carrageenan-induced edema model, although the extent of inhibition was less than that with the anti-inflammatory drug. (Fig. 4)

Figures

 

3．Summary

1) Chlorella powder exhibited statistically significant inhibition of swelling of the foot.

2) Chlorella powder exhibited a tendency to inhibit destruction of the ankle.

3) Chlorella powder exhibited a tendency to inhibit increase in serum Il-1β.

The above findings suggested that continuous ingestion of chlorella powder could be effective in inhibiting the onset of acute and chronic inflammation.