Aloe's Effectiveness As An Anti-Inflammatory Agent
By Hiroko Saito, Department Of Pharmacy
Aichi Cancer Center - 1993
Aloe has long bee effective as an anti-inflammatory, so an investigation was undertaken
to determine whether Aloctin A inhibits adjuvant arthritis in rats and carrageenin induced edema in rats. Aloctin A
is a glycoprotein isolated by ammonium sulphate precipitation, pH dependant isolated and gel filtration from Aloe
arborescens Miller.
Previous publications have demonstrated that Aloctin A inhibits the growth of
methylcholanthrene-induced fibrosarcoma in vivo with the mechanism appearing to be host related. Since Aloe
arborescens Miller has been used as an anti-inflammatory in folklore medicine its effect on adjuvant arthritis and
carrageenin-induced edema was examined. The model used for adjuvant arthritis was developed by Newbould, and the
carrageenin-induced edema used the method of Winters et al.1, 2
Adjuvant Arthritis Formation And Compound TreatmentIndomethacin, prednisolone
carrageenin, liquid paraffin and heat killed Mycobacterium butyricum were used. The Aloctin A was prepared
according to the method of Suzuki et al.3 The arthritic syndrome was induced in Sprague Dawley rats by
an intradermal injection of 0.10 ml of liquid paraffin containing 0.6 mg of heat killed Mycobacterium into the
interplantar surface of the right hind foot. The compounds to be tested were administrated either orally or
intraperitoneally each day for 15 days beginning one day prior to the injection of the phlogistic agent into the
foot.
In the preliminary investigation, the oral administration of Aloctin A did not affect
adjuvant arthritis at the doses tested in this experiment.
Aloctin A was suspended in 0.9% sodium chloride, and was administered intraperitoneally
through this investigation. The Indomethacin and prednisolone in an aqueous suspension were administered by gastric
gavage. The control animals received adjuvant but no drug. The body weight and foot volumes were recorded at
regular intervals.
Edema Formation And Compound TreatmentEdema was induced in the hind paw of the rats
by a sub-cutaneous injection of 0.05 ml of 1% carrageenin solution in 0.9% sodium chloride. The Aloctin A suspended
in 0.9% sodium chloride was administered intraperitoneally 30 minutes prior to the injection of the phlogistic
agent. Indomethacin in aqueous suspension was administered by gastric gavage.
The volume measurements were made immediately prior to and at one, three, four, and five
hours after injection of the phlogistic agent. The volume measurement was determined by the water displacement
method. The effects of the compounds were expressed in terms of percent inhibition in the swelling volume of the
control animal versus the treated animals.
The results in Table 1 clearly show that Aloctin A at all dose levels effectively
suppressed the swelling of adjuvant arthritis, with the optimal dose level being 5 mg/kg/day. The activity of
Aloctin A given intraperitoneally appeared to be higher than that of indomethacin given p.o., and was nearly equal
to prednisolone given p.o. During the course of this experiment no side reactions of Aloctin A were noted.
Table 1Effect of Aloctin A, Indomethacin and Prednisolone on arthritis induced in rats by mycobacterial
adjuvant.
|
Compound
|
Daily Dose
(mg/kg)
|
Route
|
B.W. Gain
Day 0-21
(g +/- S. E.)
|
Inhibition
Injected
Day 14
|
(%)
Hind Paw
Day 21
|
Inhibition
Secondary
Day 14
|
(%)
Lesion
Day 21
|
| Aloctin A |
0.5
|
i.p.
|
15 +/- 12
|
14.4
|
9.3
|
28.4
|
17.4
|
|
2.5
|
i.p.
|
35 +/- 9
|
39.3
|
27.0
|
23.9
|
30.3
|
|
5.0
|
i.p.
|
45 +/- 8
|
57.2
|
56.6
|
43.3
|
72.3
|
|
7.5
|
i.p.
|
5 +/- 1
|
49.4
|
29.5
|
39.3
|
-2.3
|
|
10.0
|
i.p.
|
5 +/- 1
|
22.6
|
4.6
|
28.6
|
-5.3
|
| Indomethacin |
2.0
|
p.o.
|
-10 +/- 7
|
38.1
|
23.9
|
12.1
|
-1.2
|
| Prednisolone |
2.0
|
p.o.
|
0 +/- 1
|
58.3
|
43.2
|
82.2
|
35.7
|
| Control |
|
|
10 +/- 9
|
0
|
0
|
0
|
0
|
Six rats per group were used.
Each value of Inhibition (%) is average of six rats per group.
Aloctin A showed marked inhibition of edema in the carrageenin foot paw swelling assay (Table 2). When Aloctin A
was given intraperitoneally 30 minutes prior to the injection of the carrageenin, a marked inhibition of edema was
observed three hours after the injection. The effect of Aloctin A showed a dose-response relationship up to 10
mg/kg.
Table 2Effect of Aloctin A and Indomethacin on swelling of rat hind paw induced by carrageenin.
|
Compound
|
Dose
(mg/kg)
|
Route
|
Inhibition
(%) 1
|
Inhibition
(%) 3
|
Inhibition
(%) 4
|
Inhibition
(%) 5 (hr)
|
| Aloctin A |
0.5
|
i.p.
|
10.2
|
32.3
|
36.0
|
26.4
|
|
1.0
|
i.p.
|
10.8
|
66.5
|
64.2
|
55.8
|
|
5.0
|
i.p.
|
12.5
|
50.8
|
55.6
|
59.2
|
|
7.5
|
i.p.
|
4.8
|
89.2
|
88.0
|
94.6
|
|
10.0
|
i.p.
|
2.2
|
92.8
|
93.4
|
95.3
|
| Indomethacin |
0.5
|
p.o.
|
-14.4
|
18.8
|
19.2
|
29.5
|
|
1.0
|
p.o.
|
-28.5
|
32.6
|
41.5
|
40.8
|
|
2.0
|
p.o.
|
12.5
|
59.5
|
63.4
|
59.0
|
Each value is mean of six rats per group.
The present experiments demonstrated that Alotin A inhibits adjuvant arthritis and
carrageenin-induced edema in rats. Alotin A is a new type of anti-inflammatory. Anti-inflammatory drugs reported to
date are classified as steroids, non-steroids, immunosupressive drugs and antiphlogistic agents, whereas Aloctin A
is a glycoprotein. Further studies are needed to construct a reasonable hypothesis for the mode of action of
Aloctin A.
References1 Newbould BB: Chemotherapy of arthritis induced in rats by
mycobacterial adjuvant. Brit. J. Pharmacol. 21, 127-136.
2 Winter CA; Risley EA; Nues GW: Carrageenin-induced edema in hind paw of the
rat as an assay for anti-inflammatory drugs. Proc. Soc. exp. Biol. Med. 111, 544-547 (1982).
3 Suzuki I; Saito H; Inouse S; Migita S; Takahashi T: Purification &
characterization of two lectins from Aloe arborescens Miller. J. Biochem 85, 163-171 (1979).
Whole Leaf Aloe Vera - Aloe's Effectiveness As An Anti-Inflammatory Agent
|