QUILLAIA EXTRACTS
Explanation
This compound has not previously been reviewed by the Joint
FAO/WHO Expert Committee on Food Additives.
Quillaia (synonyns; soapbark, soap tree bark, murillo bark,
quillaia, Panama bark, Panama wood, and China bark) is the dried inner
bark derived of cork of Quillaia saponaria Molina and other species
of Quillaia (Rosaceae). This plant is a large evergreen tree with
shiny, leathery leaves and thick bark, which is native to China and
Peru and cultivated in southern California (Leung, 1980).
Quillaia extract is the aqueous extract of the above bark and
contains 3 or possibly 4 triterpenoid saponins (2 major, 1 minor, 1
trace) constituting about 10% of the extract. The sugars, glucose,
galactose, arabinose, xylose, rhamnose and 2 further unidentified
sugars, are also present. The extract also contains tannin and about
11% calcium oxalate. The 2 major saponins are quillaia sapogenin and
quillaic acid (Commission of the European Communities, 1978).
BIOLOGICAL DATA
TOXICOLOGICAL STUDIES
General biological activity
Saponins vary widely in the kind and intensity of biological
activity. Some of the more important reported activities include
haemolytic, local irritant, inflammatory (especially on intestine),
cytotoxic and antimicrobial.
Powdered quillaia bark or saponin concentrate has highly local
irritant and stimulatory properties. It also possesses expectorant
properties as well as depressant activity on the heart and
respiration. Severe toxic effects due to large oral doses have been
reported to be liver damage, respiratory failure, gastric pain,
diarrhoea, haemolysis of red blood corpuscles, convulsions and coma
(Leung, 1980).
Special studies on pharmacological effects
Saponins extracted with alcohol from soapbark trees, administered
orally to rabbits with experimental atherosclerosis, resulted in
increased plasma lecithin to cholesterol ratio, normalized blood
cholesterol levels, and decreased elevated blood pressure.
Subcutaneous injection of the saponin extract did not affect
atherosclerotic symptoms (Efimova et al., 1966).
Groups of 12 Swiss mice (strain and sex undefined) were injected
in the footpad with aliquots of 7 different 5% extracts of Quillaia
saponica bark. Animals surviving after 24 hours and control animals
were sacrificed. Degree of oedema was measured in the mice. Haemolysis
of rabbit erythrocytes was also measured using the same quillaia
extracts. The adjuvant strength of the various quillaia extracts in
stimulating immunity to staphylococcal toxin was also measured. The
samples of quillaia showed no relationship between their inflammatory
effect on mice, their haemolytic effect for rabbit erythrocytes, their
toxicity for Swiss mice and their antistaphylococcal immunity-
stimulation effect for rabbits (Richou et al., 1965).
Acute toxicity (Saponins extracted from the soapbark tree)
LD50
Species Route (mg/kg bw) Reference
Mouse Oral 1 625 Efimova et al., 1966
s.c. 650 Efimova et al., 1966
i.p. 275 Efimova et al., 1966
i.v. 275 Efimova et al., 1966
Short-term studies
Rat
Groups of 15 male and 15 female weanling rats of the CFE strain
were housed 5 per cage and fed on diets containing 0 (control), 0.6,
2.0 or 4.0% quillaia extract for 13 weeks. Groups of 5 male and 5
female rats from the same lot of animals were fed on diets containing
0 (control), 2.0% or 4.0% quillaia extract for 2 or 6 weeks.
Animal weights and food intake were measured at the beginning of
the experiment and weekly throughout the study. Urine analysis was
carried out during the final week of the study. At sacrifice, absolute
and relative organ weights were determined, and a histological
examination was made of tissue and organs from the 4% group.
Haematological studies and serum chemistry were carried out for all
groups.
No abnormalities of behaviour or condition were seen in the rats
receiving quillaia extract. Body weights of rats fed the highest level
of quillaia extract (4%) were significantly lower than controls up to
day 78 in males, but only for the first 2 weeks in females. Food and
water consumption was reduced in both sexes at all dietary levels, but
by the end of the study the weights of the treated rats did not differ
significantly from those of the controls. The feeding of quillaia
saponin did not affect the results of haematological examinations,
serum and urine analyses, renal concentrating ability or urinary cell
excretion. The relative liver weight was reduced in males given 2% or
4% quillaia extract, and the relative stomach weight was increased in
both sexes at the same levels. No histopathological effects
attributable to treatment were found. The no-effect level in this
study was 0.6% of the diet equivalent to an intake of approximately
400 mg/kg bw per day (Gaunt, Grasso & Gangolli, 1974).
Long-term studies
Mouse
Groups of 48 male and 48 female TO strain mice were fed diets
containing 0, 0.1, 0.5 and 1.5% quillaia extract for 84 weeks. The
mice were observed regularly for abnormalities of condition or
behaviour, and some males were weighed at intervals. Haematological
studies were made at weeks 24, 56 and 84. No compound-related effects
were reported. At the highest dose level, there was a decreased weight
gain in the male mice. Quillaia at the levels fed had no adverse
effect on condition, behaviour or death rate. At the termination of
the study a detailed autopsy and histopathological examination of
tissues and organs showed no compound-related effects.
Quillaia extract fed at levels up to 1.5% in the diet (2.2 g/kg
bw per day) was not carcinogenic; the slightly lower body weight gain
in the mice on the highest dietary level and some organ weight
changes, albeit of doubtful significance, indicate a no-effect level
for quillaia extract of 0.5% in the diet (or 700 mg/kg bw per day)
(Phillips et al., 1979).
Rat
Groups of 48 male and 48 female rats were housed in groups of 4
and fed on diets containing 0 (control), 0.3, 1.0 or 3.0% quillaia
extract for 108 weeks. Rats used in the study were a Wistar-derived
strain from a specified pathogen-free breeding colony. Haematological
studies were made at weeks 15, 25, 52 and 108 of the study and
urinalysis at weeks 13, 24 and 78. At the termination of the study a
complete autopsy was carried out, including histological examination
of the tissues and organs.
Male rats fed the highest dietary level had lower body weights
throughout the experiment than control animals, the differences being
statistically significant between 10 and 22 months. Females on the
lowest dietary level had significantly higher body weights than the
control animals during the first 6 months of the study. The lower body
weights and reduced incidence of glomerulonephrosis in the male rats
fed 3% quillaia are considered to be due to reduced food consumption.
Preference tests run before the start of the 2-year study showed that
the rats avoided diet containing quillaia extract. Haematological
parameters and urinalysis showed no compound-related effects and were
within normal range.
In general, the incidence of histological findings was similar in
treated and control animals. The only lesions with incidences greater
than those of control were fibrosis of the heart and dilatation of the
glands of the gastric mucosa in females, at the lowest dietary level
of quallaia. These effects are considered to be fortuitous since there
was no dose relationship and no similar occurrence in males.
A variety of benign and malignant tumours were found. The
incidence of haemangiomas and haemangiosarcomas in the lymh nodes were
similar in both control and treated animals. The only tumour showing a
statistical difference from the control incidence was thyroid adenoma,
which occurred more frequently in females fed 1% quillaia extract in
the diet. This finding was not considered treatment related, since
incidence did not increase with level of quillaia extract fed and the
total incidence of thyroid adenoma in both sexes fed 1% quillaia
extract was not statistically different from the total control
incidence (Drake et al., 1982).
Comments
A short-term study in the rat showed that even at the highest
test level (up to 4% of the diet) the only effects observed were some
decrease in body weight gain, and relative liver weight. In lifetime
studies in the mouse and rat, at dietary levels up to 1.5%, there were
minor changes in body weight gain, and some relative organ weights. No
compound-related histological changes were reported. The no-effect
level for quillaia extract in the diet of mice was 0.5% and in the rat
1.0%. No evaluation is possible at this time because specifications
for quillaia extract are not available.
EVALUATION
Estimate of acceptable daily intake for man
Not allocated.
REFERENCES
Commission of the European Communities (1978) Report of the Scientific
Committee for Food, Emulsifiers, Stabilizers, Thickeners and
Gelling Agents, Brussels
Drake, J. J.-P. et al. (1982) Long-term toxicity study of quillaia
extract in rats, Fd. Cosmet. Toxicol., 20, 15-23
Efimova, T. G. et al. (1966) The action of soapbark tree Quillaia
saponaria saponins on blood pressure and cholesterol content in
animals, Farm. Zh. (Kiev), 21(16), 45-49
Gaunt, I. F., Grasso, P. & Gangolli, S. D. (1974) Short-term toxicity
of quillaia extract in rats, Fd. Cosmet. Toxicol., 12,
641-650
Leung, A. Y. (1980) Encyclopedia of common natural ingredients used
in food, drugs, and cosmetics, John Wiley & Sons, NY
Phillips, J. E. et al. (1979) Long-term toxicity study of quillaia
extract in mice, Fd. Cosmet. Toxicol., 17, 23-27