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Cokelaere, M.M., G. Flo, P. Daenens, E. Decuypere, M. Van
Boven, and S. Vermaut. 1996. Food intake inhibitory activity of simmondsin
and defatted jojoba meal: Dose-response curves in rats. p. 377-382. In: J.
Janick (ed.), Progress in new crops. ASHS Press, Arlington, VA.
Food Intake Inhibitory Activity of Simmondsin and Defatted Jojoba Meal:
Dose-Response Curves in Rats
Marnix M. Cokelaere, Gerda Flo, Paul Daenens, Eddy Decuypere, Maurits Van
Boven, and Sabien Vermaut
- METHODOLOGY
- Experiment 1
- Experiment 2
- RESULTS AND DISCUSSION
- Experiment 1
- Experiment 2
- SUMMARY
- REFERENCES
- Table 1
- Table 2
- Fig. 1
- Fig. 2
Jojoba (Simmondsia chinensis) is a shrub indigenous to the Sonoran
desert of Arizona, California, and Mexico. The seeds contain liquid wax esters
used as a high-temperature lubricant and in cosmetics. The meal by-product
remaining after wax extraction cannot be used as animal feed because of the
presence of several cyanide-containing glycosides, such as simmondsin,
simmondsin 2'-ferulate, and several minor simmondsin derivatives (Booth et al.
1974; Elliger et al. 1973, 1974a, b; Van Boven et al. 1994a, b, c, 1995).
Simmondsin and simmondsin-containing jojoba meal induce food intake inhibition,
emaciation and, occasionally mortality, and because of this, simmondsins have
been considered toxic (Booth et al. 1974; Ngoupayou et al. 1982; Verbiscar et
al. 1980, 1981). However, long-term administration of lower doses of
simmondsin or defatted jojoba meal to growing rats, which induced a sustained
food intake inhibition of about 20%, showed no toxic effects (Cokelaere et al.
1993a, b), although, real toxicity, especially at higher doses cannot yet be
ruled out. Furthermore, it has been demonstrated that food intake inhibition
in rats can be reversed by the cholecystokinin receptor antagonist, devazepide
(Cokelaere et al. 1995a, b), suggesting that the anorexia seen following
simmondsin administration is due to stimulation of the cholecystokinin
satiation system. Other studies have shown that the food intake reduction
induced with lower doses of defatted jojoba meal is due to satiation (Cokelaere
et al. 1995c). Some authors claim that the anorexia induced by defatted jojoba
meal is caused by its bitter taste due to the presence of simmondsin
2'-ferulate and tannins, the latter being found in the skin of the jojoba seed
(Medina et al. 1988, 1990; Ngoupayou et al. 1985; Verbiscar et al. 1981).
Simmondsin itself is tasteless (Verbiscar et al. 1981).
In the present study, the anorexic effects of simmondsin and simmondsin
2'-ferulate are compared and dose-response curves constructed for food
containing pure simmondsin or defatted jojoba meal (from commercially available
presscake or deskinned jojoba seeds) in order to discriminate between the
satiating effects of the simmondsins and other factors present in jojoba
seeds.
The effects of jojoba meal from Israel and the United States will be compared.
Adult male Wistar rats, weighing 350 to 425 g, were housed in iron wire cages
under normal laboratory circumstances (22°C, 40% to 60% relative humidity,
light from 08:00 h to 20:00 h, free access to water and food). Food was
provided as meal in specially designed mangers to avoid spilling (Scholz,
Overijse, Belgium).
In the first experiment, 10 rats (5 groups of 2) were used to compare the food
intake inhibitory effects of food supplemented with pure simmondsin (S) and
simmondsin 2'-ferulate (SF), the two major simmondsins of jojoba meal. The
control daily food intake was measured for 3 days (group C), then the rats were
given food supplemented with 0.5% (w/w) of pure simmondsin for another 3 days
(group SM) and the food intake measured daily. After a recovery period of 2
weeks, they were given normal food supplemented with 0.5% (w/w) of simmondsin
2'-ferulate for 3 days (group SMF) and the food intake again measured daily.
In a second series of experiments, the food intake inhibitory effect of food
supplemented with increasing doses of simmondsin (0.1%, 0.25%, 0.50%, 0.75%,
and 1.00%) (group SIM) was compared with the effect of food supplemented with
increasing doses of 4 different preparations of defatted jojoba meal (Table 2).
These jojoba meals were obtained from commercially available presscake (1) from
Israel (Jojoba Israel, Kibbutz Hatzarim) (group PCI) or (2) from the United
States (International Flora Technologies, Apache Junction) (group PCU), from
deskinned jojoba seeds from (3) Israel (group DI), and (4) from the United
States (group DU). The Israeli seeds were deskinned by peeling after cooking
for 30 min, while American seeds were deskinned using razor blades. The seeds
were then pressed in a hand screw press to extrude most of the jojoba oil. The
presscakes and pressed deskinned Israeli seeds were Soxhlet-extracted using
n-hexane for 8 h, while the pressed deskinned American seeds were defatted by
stirring in a container with n-hexane at room temperature. Pure simmondsin was
prepared and the content of S and SF determined as described previously (Van
Boven et al. 1993, 1994b).
Fifty rats, caged in pairs, were used for each experiment, 10 for each
simmondsin (S) or jojoba meal concentration. Rats were provided normal food
for 7 days and the food intake was measured daily to obtain the control food
intake; they were then given the S- or jojoba meal-supplemented foods for a
further 7 days, and the daily food intake was recorded. The amount of food
eaten during treatment was then expressed as a percentage of their own control
intake.
The daily food intake of control group C was 20.7±0.4 g. 0.5% pure S or SF
mixed in the food reduced food intake to 7.6±1.4 g or 12.5±1 g,
respectively; in terms of food intake reduction, on a weight basis, SF was
therefore only 62.5% as effective as S. However, the molecular weight of S is
only 68% that of SF (375 and 551, respectively) and this therefore suggests
that a similar food intake reduction is obtained with equimolar amounts of SF
and S. These results contradict the suggestion of Weber (1978, quoted by
Verbiscar et al. 1981) that SF has no significant involvement in anti
nutritional aspects of jojoba meal.
The sum of the contents of S and SF x 0.68 (in %), of defatted jojoba meal was
used as indicator of simmondsin activity (SA). The concentrations of defatted
jojoba meals to be mixed in the food for the second experiment were calculated
taking their SA into account.
The S and SF contents of the different meals are shown in Table 1 and the
concentrations to be mixed with the food in Table 2. The control daily food
intake was 21.05±0.45 g (pooled for the 5 subgroups).
Fig. 1 shows the food intake inhibitory effect of food supplemented with
increasing doses of pure simmondsin (SIM) or defatted jojoba meal obtained
after deskinning jojoba seeds from Israel (DI) and the United States (DU).
There was a clear, and similar, dose-response effect for SIM, DI, and DU up to
a SA of 0.75% and it was only at a SA of 1%, that a greater degree of anorexia
was seen in DI and DU animals compared with the SIM group. Food intake
reduction was identical in the DI and the DU groups, although the jojoba meal
concentration was significantly higher for the DI group (Table 2). It can thus
be concluded that, up to a SA of 0.75%, the anorexic effect of food containing
defatted jojoba meal, prepared from deskinned jojoba seeds, can be predicted
from its SA rather than from the concentration of the jojoba meal mixed in the
diet, and that it is only at higher concentrations that other factors, such as
other minor simmondsins or taste effects, may play an additional role. The SF
content of food supplemented with high concentrations of jojoba meal may
produce a bitter taste, as SF is the major bitter principle of jojoba meal
(Medina et al. 1990). An anorexic effect of other simmondsin analogues,
present at lower concentrations in defatted jojoba meal, has also been
suggested (Verbiscar et al. 1981) but remains to be proven. On the basis of
the present results, they may have only a small additional effect. This
confirms the results of Abbott et al. (1990) who fed mice with jojoba meal,
detoxified enzymatically or with microorganisms that degraded simmondsin and
simmondsin 2'-ferulate but did not attack the other simmondsin derivatives.
Mice did well on this treated jojoba meals.
Fig. 2 shows the food intake reducing effect of food containing defatted jojoba
meal produced from commercially available presscake. Up to a SA of 0.25%, PCI
and PCU had a similar anorexic effect as SIM. At higher concentrations, food
intake reduction became more pronounced, especially for PCU, although the
difference in concentration of defatted jojoba meal used to obtain similar SAs
in the PCI and PCU groups, were very small. This difference in anorexic effect
probably results from a more pronounced influence of other factors than SA in
jojoba meal. Taste could be one such factor since the skin of jojoba seeds
(about 20% of the presscake, data not shown) contains high concentrations of
tannins and taste very bitter (Verbiscar and Banigan 1978; Medina et al. 1990).
The American jojoba seeds used were much smaller than those from Israel, so the
presscake made from complete American jojoba seeds contained a higher
percentage of skin than that from Israel and probably caused a more pronounced
aversion to the supplemented food. This effect, additional to the anorexic
effect of the simmondsins, was already evident at a lower SA content than in
the experiments using deskinned seeds, which again points to a supplementary
taste effect of skin components.
The present results confirm the results of Medina et al. (1990) in rats using
jojoba meal made from complete or deskinned seeds, showing that debittering and
tannin-extraction reduces the anorexic effect of jojoba meal. The
dose-response curves obtained in the present experiment are in good agreement
with previous separate results in rodents (Cokelaere et al. 1993a, b; Verbiscar
et al. 1981), rabbits (Ngoupayou et al. 1985), cattle (Swingle et al. 1985), or
chicken (Arnouts et al. 1993; Ngoupayou et al. 1982). We therefore conclude
that, in rats, the anorexic effect of food containing S is dose-related,
sustained, and predictable. On a molar base, SF and S are equipotent. Using
the combined % S + % (SF x 0.68) content, designated as SA, the anorexic effect
of food containing defatted jojoba meal prepared from deskinned jojoba seeds
can be predicted from its SA up to a SA of 0.75%. At higher concentration of
jojoba meal, a more pronounced anorexic effect is observed. Food mixed with
defatted jojoba meal containing the skin of jojoba seeds, at a SA higher than
0.25%, has a more pronounced anorexic effect than can be predicted from its SA.
This additional anorexic effect is probably due to taste or to other factors
present in the skin.
Over a 3-day period, the anorexic effects of pure simmondsin (MW=375) and
simmondsin-2'-ferulate (MW = 551) were compared in adult male rats.
On a weight base, the anorexic effect of simmondsin-2'-ferulate was only ±68%
of that of simmondsin, but, on molar base, they were equipotent. The sum of
the concentrations, expressed as percent, of simmondsin plus (simmondsin 2'-
ferulate x 0.68) in jojoba meal was taken as an indicator of simmondsin
activity (SA).
Dose-response curves of food intake inhibition, produced by increasing
concentrations of pure simmondsin mixed in normal food (0.1% to 1.0%), were
obtained in adult rats over a 7-day period and compared with those for
increasing concentrations of defatted jojoba meal. The anorexic effect of pure
simmondsin was dose-related up to a concentration of 1% in the diet (15% to 70%
food intake reduction). Up to concentrations giving a SA of 0.75% in the diet,
hexane-defatted jojoba meal, obtained from deskinned seeds, gave a similar
dose-response curve to pure simmondsin and the anorexic effect of these jojoba
meal containing mixtures could be predicted from their SA.
Hexane-defatted jojoba meal, obtained from commercially available jojoba
presscake, had a similar food intake reducing effect to simmondsin up to
concentrations giving a SA of 0.25%, but, at higher concentrations food intake
was reduced to a greater extent than expected from the SA. This supplementary
effect is probably due to the presence of the skins in the press cake, causing
a bitter taste.
- Abbott, T.P., L.K. Nakamura, T.C. Nelsen, H.J. Gasdorf, G.A. Bennett, and R.
Kleiman. 1990. Microorganisms for degrading simmondsin and related cyanogenic
toxins in jojoba. Appl. Microbiol. Biotechnol. 34:270-273.
- Arnouts, S., J. Buyse, M.M. Cokelaere, and E. Decuypere. 1993. Jojoba meal
(Simmondsia chinensis) in the diet of broiler breeder pullets:
physiological and endocrinological effects. Poultry Sci. 72: 1714-1721.
- Booth, A.N., C.A. Elliger, and A.C. Waiss Jr. 1974. Isolation of a toxic factor
from jojoba meal. Life Sci. 15:1115-1120.
- Cokelaere, M., J. Buyse, P. Daenens, E. Decuypere, E.R. Kühn, and M. Van
Boven. 1993a. Influence of jojoba meal supplementation on growth and organ
function in rats. J. Agr. Food Chem. 41:1444-1448.
- Cokelaere, M., J. Buyse, P. Daenens, E. Decuypere, E.R. Kühn, and M. Van
Boven. 1993b. Fertility in rats after long term jojoba meal supplementations.
J. Agr. Food Chem. 41:1449-1451.
- Cokelaere, M., P. Busselen, G. Flo, P. Daenens, E. Decuypere, E.R. Kühn,
and M. Van Boven. 1995a. Devazepide reverses the anorexic effect of simmondsin
in the rat. J. Endocrinol. 147:473-477.
- Cokelaere, M., P. Daenens, G. Flo, E.R. Kühn, M. Van Boven, S. Vermaut, J.
Buyse, and E. Decuypere. 1995b. Simmondsin: physiological effects and working
mechanism in rats. In: L.H. Princen (ed.), Proc. 9th Int. Conf. on Jojoba and
its uses. Sept. 25-30, 1994. Catamarca, in press.
- Cokelaere, M., G. Flo, E. Decuypere, S. Vermaut, P. Daenens, and M. Van Boven.
1995c. Evidences for a satiating effect of defatted jojoba meal. Ind. Crops
Prod. 4:91-96.
- Elliger, C.A., A.C. Waiss Jr., and R.E. Lundin. 1973. Simmondsin, an unusual
2-cyanomethylenecyclohexyl glucoside from Simmondsia californica. J. Chem. Soc.
Perkin Trans. 19:2209-2212.
- Elliger, C.A., A.C. Waiss Jr., and R.E. Lundin. 1974a. Structure and
stereochemistry of simmondsin. J. Org. Chem. 39:2930-2931.
- Elliger, C.A., A.C. Waiss Jr., and R.E. Lundin. 1974b. Cyanomethylenecyclohexyl
glucosides from Simmondsia californica. Phytochemistry 13:2319-2320.
- Medina, L.A. and A. Trejo-Gonzales. 1990. Detoxified and debittered jojoba
meal: biological evaluation and physical-chemical characterization. Cereal
Chem. 67:476-479.
- Medina, L.A., A. Trejo, and M. Sanchez-Lucero. 1988. Elimination of toxic
compounds, nutritional evaluation and partial characterization of proteins from
jojoba meal. p. 423-429. In: A.R. Baldwin (ed.), Proc. 7th Int. Conf. on Jojoba
and its uses. Champaign, IL.
- Ngoupayou, J.D.N., P.M. Maiorino, and B.L. Reid. 1982. Jojoba meal in poultry
diets. Poultry Sci. 61:1692-1696.
- Ngoupayou, J.D.N., P.M. Maiorino, W.A. Schurg, and B.L. Reid. 1985. Jojoba meal
in rabbit diets. Nutr. Rep. Int. 31:11-19.
- Swingle, R.S., M.R. Garcia, F.J. Delfino, and F.L. Prouty. 1985. An evaluation
of Lactobacilli acidophillus-treated jojoba meal in beef cattle diets.
J. Anim. Sci. 60:832-838.
- Van Boven, M., N. Blaton, M. Cokelaere, and P. Daenens. 1993. Isolation,
purification and stereochemistry of simmondsin. J. Agr. Food Chem.
41:1605-1607.
- Van Boven, M., S. Toppet, M.M. Cokelaere, and P. Daenens. 1994a. Isolation and
structural identification of a new simmondsin ferulate from jojoba meal. J.
Agr. Food Chem. 42:1118-1121.
- Van Boven, M., P. Daenens, M.M. Cokelaere, and G. Janssen. 1994b. Isolation and
structure elucidation of the major simmondsin analogues in jojoba meal by two
dimensional NMR spectroscopy. J. Agr. Food Chem. 42:2684-2687.
- Van Boven, M., P. Daenens, M. Cokelaere, and E. Decuypere. 1994c. Extraction
and liquid chromatographic method for the determination of simmondsin in
plasma. J. Chromat. 655:281-285.
- Van Boven, M., P. Daenens, and M. Cokelaere. 1995. New simmondsin 2'-ferulates
from jojoba meal. J. Agr. Food Chem. 43:1193-1197.
- Verbiscar, A.J. and T.F. Banigan. 1978. Composition of jojoba seed and foliage.
J. Agr. Food Chem. 26:1456-1459.
- Verbiscar, A.J., T.F. Banigan, C.W. Weber, B.L. Reid, R.S. Swingle, J.E. Trei,
and E.A. Nelson. 1981. Detoxification of jojoba meal by Lactobacilli. J.
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- Verbiscar, A.J., T.F. Banigan, C.W. Weber, B.L. Reid, J.E. Trei, E.A. Nelson,
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Table 1. Simmondsin (S) and simmondsin 2'-ferulate (SF) concentrations
of different jojoba meals. (SA = calculated simmondsin activity; DI = defatted
jojoba meal from deskinned seeds from Israel; DU = defatted jojoba meal from
deskinned seeds from the United States; PCI = defatted complete jojoba meal
from Israel, PCU = defatted complete jojoba meal from the United States.
| Concentration (%) |
Defatted jojoba meal | S | SF | SA |
DI | 4.0 | 1.4 | 4.9 |
DU | 7.2 | 1.8 | 8.5 |
PCI | 4.8 | 1.4 | 5.6 |
PCU | 4.6 | 1.2 | 5.4 |
Table 2. Concentrations of defatted jojoba meal mixed in the food of
rats to obtain supplemented food with an SA equivalent to that of pure
simmondsin. (DI = defatted jojoba meal from deskinned seeds from Israel; DU =
defatted jojoba meal from deskinned seeds from the United States; PCI =
defatted complete jojoba meal from Israel, PCU = defatted complete jojoba meal
from the United States.
| Amount of defatted jojoba meal (%) equivalent to stated simmondsin amount |
| Simmondsin |
Defatted jojoba meal | 0.10% | 0.25% | 0.50% | 0.75% | 1.00% |
DI | 2.0 | 5.0 | 10.0 | 15.0 | 20.0 |
DU | 1.2 | 3.0 | 5.9 | 8.6 | 11.9 |
PCI | 1.7 | 4.4 | 8.7 | 13.0 | 17.4 |
PCU | 1.9 | 4.7 | 9.3 | 14.0 | 18.6 |

Fig. 1. Food intake as percent of control food intake (±SEM), at
increasing concentrations of pure simmondsin and defatted jojoba meal from
deskinned jojoba seeds (Israel and United States), n = 10; comparison of means
within concentrations by Duncan multiple range test, 5% level.

Fig. 2. Food intake as percent of control food intake (±SEM) at
increasing concentrations of pure simmondsin and defatted jojoba meal from
commercial presscake (Israel and United States), n = 10; comparison of means
within concentrations by Duncan multiple range test, 5% level.
Last update August 21, 1997
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