Table of Contents
Kuti, J.O. and E.S. Torres. 1996. Potential nutritional
and health benefits of tree spinach. p. 516-520. In: J. Janick (ed.),
Progress in new crops. ASHS Press, Arlington, VA.
Potential Nutritional and Health Benefits of Tree Spinach*
Joseph O. Kuti and Eliseo S. Torres
- Nutritional Composition
- Possible Antidiabetic Effect
- Nutritional Composition
- Possible Antidiabetic Effect
- Table 1
- Table 2
- Fig. 1
- Fig. 2
- Fig. 3
The tree spinach (Cnidoscolus chayamansa McVaughn, Euphorbiaceae),
called "chaya" in south Texas, is popular in Mexico and Central America and has
been introduced into the United States (mainly South Texas and Florida) for
potential uses as a leafy vegetable and/or as a medicinal plant. The plant is
an attractive shrub, 3 to 5 m tall (Breckon 1979). The leaves are broad and
may consist of 3 or more lobes with fleshy petioles (Fig. 1). The
white-colored flowers, which are usually borne on cyme-branched inflorescences,
may contain 3-forked arrangements in which the pistillate flowers are located
on the basal fork. The staminate flowers are expanded distally from the base
of the lobes. Mature seeds and fruit are rare and unknown (McVaugh 1944).
The young shoots and tender leaves of chaya are cooked and eaten like spinach.
They comprise part of the staple diet and are the main dietary source of leafy
vegetable for the indigenous people of Yucatan peninsula of Mexico and Kekchi
people of Alta Verapaz in Guatemala (Harris and Munsell 1950; Booth et al.
1992). There are many underexploited native leafy plants with potential as a
traditional food source (NAS 1975). With current renewal of interest in
household gardens, attention is being focused on promoting some of these plants
as leafy green vegetables among populations in the developing countries (FAO
1987). The edible parts of chaya plant, which taste like spinach when cooked,
provide important nutritional sources for protein, vitamins (A and C), minerals
(calcium, iron, phosphorus), niacin, riboflavin, and thiamine among populations
that cannot afford expensive foods rich in these nutrients (Yang 1979). The
plant may also constitute a potentially valuable leafy green vegetable here in
the United States and elsewhere.
Chaya traditionally has been recommended for a number of ailments including
diabetes, obesity, kidney stones, hemorrhoids, acne, and eye problems
(Diaz-Bolio 1975). Chaya shoots and leaves have been taken as a laxative,
diuretic, circulation stimulant, to improve digestion, to stimulate lactation,
and to harden the fingernails (Rowe 1994). Like most food plants such as lima
beans, cassava, and many leafy vegetables, the leaves contain hydrocyanic
glycosides, a toxic compound easily destroyed by cooking. Even though some
people tend to eat raw chaya leaves, it is unwise to do so.
While the nutritional value of chaya has been demonstrated (Martin and Ruberte
1978; Booth et al. 1992), none of the purported therapeutic values of chaya
leaves has been substantiated with scientific experimentation. Therefore, the
present study reports on nutritional composition of raw and cooked chaya leaves
and the results compared with the nutritional composition of spinach leaves.
Also a possible antidiabetic effect of the aqueous leaf extracts or chaya tea,
administered through drinking water to streptozotocin-induced diabetic rabbits,
Young leaves and shoots of C. chayamansa were collected from
greenhouse-grown plants. Raw and cooked (in microwave oven for 5 min) samples
of the leaves and shoot were analyzed for their moisture content, crude fiber,
fat, and ß-carotene using the AOAC standard methods (1984), for the
protein content (N2 content multiplied by 6.25) using modified semi
micro-kjeldahl method of Searle (1974), for mineral contents using an atomic
absorption spectrohotometer and for total carbohydrate using gas
chromatography. All samples were analyzed in triplicate. Nutritional
components and average nutritive value (ANV) of chaya leaves were compared to
spinach leaves. The ANV was calculated using the empirical formula proposed by
Grubben (1978): ANV/100g = g protein/5 + g fiber + mg Ca++/100 + mg
Fe++/2 + mg carotene + mg vit C/40
The experimental animals (rabbits) for this study were supplied by Dr. Steven
Lukefahr of the Department of Animal and Wildlife Sciences, Texas A&M
University-Kingsville. All animals were housed and maintained in compliance
with Texas A&M University-Kingsville IACUC policy on animal care and use.
The rabbits were fed with standard rabbit chow and given water ad
libitum. Diabetes was induced by a single subcuteanous injection of 60
mg/kg streptozotocin (STZ), after fasting for 18 h, according to the method
described by Bonner-Weir et al. (1981). The rabbits exhibited post-STZ blood
glucose levels that were at least double that of the pre-STZ levels one week
after diabetes had been induced.
The leaves of C. chayamansa were collected from plants grown in
the greenhouse. About 10 g of the leaves was extracted with boiling water
(1000 mL) for 30 min until the volume of the water had been reduced to 90% of
the original. The tea (900 mL) was filtered and used in the subsequent
experiments. Two groups of 8 rabbits each were used. The first group of 8
rabbits were normoglycemic (non-diabetic). Four of the normoglycemic rabbits
recieved water (control) only and the remaining 4 received chaya tea treatment
only. The second group of 8 rabbits were hyperglycemic (diabetic). Four of
the diabetic rabbits received water only and the remaining 4 received chaya tea
Before administering the tea or water (control), blood samples were obtained
from the ears of 18 h fasted nondiabetic and diabetic rabbits using a capillary
tube. Then the tea or water was administered orally through drinking water
bottles ad libitum. Blood sampling was repeated at hourly intervals for
6 h after the oral administration. Blood glucose was determined using a blood
glucometer (Miles Inc., Diagnostic Division, Elkhart, IN, U.S.). The mean
blood glucose values ±SE were determined and the significance of the
difference between the means of treated and control groups was established by
The nutritional analysis of chaya (C. chayamansa) leaves and
spinach (Spinacia oleracea L.) are presented in Table 1 for comparison.
Chaya leaves were found to contain substantially greater amounts of nutrients
than the spinach leaves. The chaya leaf is especially high in protein (5.7%),
crude fiber (1.9%), calcium (199.4 mg/100 g), potassium (217.2 mg/100 g), iron
(11.4 mg/100 g), vitamin C (164.7 mg/100 g), and carotene (0.085 mg/100 g).
The levels of chaya leaf nutrients, in this study, agree with published reports
(Martin and Ruberte 1978; Munsell et al. 1949; Booth et al. 1992) and are two
to threefold greater than most edible leafy green vegetables. In terms of the
average nutritive value, chaya leaves [14.9] is by far superior to other leafy
green vegetables such as spinach [6.4], amaranth [11.3], Chinese cabbage [7.0],
and lettuce [5.4] (Grubben 1978). While some edible leafy green vegetables are
usually good sources of mineral macronutrients (Levander 1990), chaya leaf
furnishes appreciable quantities of several of the essential mineral
macronutrients necessary for human health maintenance. For example, potassium
has been shown to be an important mineral nutrient in the control of
hypertension and in the reduction of risks of stroke (NRC 1989), calcium is
important for ossification and iron is necessary for normal hematopoiesis
(Hodges et al. 1978). Brise and Hallberg (1962) reported that vegetables, such
as chaya, with high vitamin C content may enhance absorption of nonheme iron.
Analysis of raw and cooked samples of chaya leaves revealed that cooking may
increase the relative composition of carbohydrate and fat and decrease relative
composition of crude fiber and protein (Fig. 2). On the other hand, cooked
samples of chaya leaves were considerably higher in calcium, phosphorus and
iron while the potassium content was relatively lower than in the raw samples
(Fig. 3). The increase in some of the mineral nutrients may be due to the
cooking process, which allows extraction of the nutrients from the tissues,
therefore increasing the percentage of mineral elements while decreasing
moisture content (Booth et al. 1992).
Following the oral administration of chaya tea, the blood glucose levels of the
diabetic rabbits were gradually lowered from a high of 118 (baseline at 0.0 h)
to 87 six hours after administration. The blood glucose level of 87 is similar
to blood glucose levels of normoglycemic rabbits on drinking water (Table 2).
The blood glucose levels of non-diabetic control rabbits that were given chaya
tea showed a slight increase (i.e. hyperglycemia) above the baseline 85 at 1 to
2 h after administration, but rapidly stabilized thereafter (Table 2).
The reason for this transient hyperglycemia is unknown and needs to be
investigated. The results obtained in this study suggest that in STZ-induced
diabetic rabbits, aqueous leaf extracts of C. chayamansa may be
effective for treatment of non-insulin dependent diabete mellitus (NIDDM)
symptomatology. This is a first report on hypoglycemic effect of chaya plants.
The present report is preliminary in nature and additional studies will be
needed to properly characterize the antidiabetic potential of chaya in diabetic
animals. Also further studies will be necessary to determine the effective
dosage, mechanism of the hypoglycemic activity and the active hypoglycemic
principle present in the leaves of C. chayamansa.
The potential of C. chayamansa for human food and health has a
significant implication for the plant as a horticultural crop. Although demand
for chaya, as a medicinal plant, has recently increased among the Hispanic
population in the United States, the plant has the potential to make a
significant nuritional contribution to the vegetable diet as well, because of
its high nutrient content. The development of chaya as a new horticultural
crop would transcend the ethnic popularity and create a worldwide market for
the plant and its products, whether as a leafy green vegetable and/or as a
therapeutic herbal tea.
It is noteworthy that the chaya plant is drought resistant, which is of a
particular value in areas with short seasonal rainfall and shortage of green
vegetables (Peregrine 1983). Growth of the plant is rapid and edible leaves
and shoots could be produced within a short period (8 to 10 weeks).
Propagation by cutting is easy and the woody stem sections readily root. Few
pests and diseases are known to be of any significance in the cultivation of
chaya plants. One disadvantage is the presence of toxic hydrocyanic glucosides
in the leaves. However, cooking, which is essential, inactivates the toxic
compound. Other Cnidoscolus (chaya) species are being examined in our
laboratory at Texas A&M University-Kingsville to genetically select species
with high leaf and shoot biomass yield and lower hydrocyanic glycoside content.
Additionally, we are conducting research on genetic improvement, propagation,
field production, potential for processing and marketing of chaya and its
products in south Texas.
- AOAC. 1984. Official methods of analysis, 14th ed. Assoc. Official Anal. Chem.,
- Booth, S., R. Bressani, and T. Johns. 1992. Nutrient content of selected
indigenous leafy vegetable consumed by Kekchi people of Alta Verapaz,
Guatamela. J. Food Compos. Anal. 5:25-34.
- Bonner-Weir, S., D.F. Trent, R.N. Honey, and G.C. Weir. 1981. Responses of
neonatal rat islets to streptozotocin-limited ß-cell regeneration and
hyperglycemia. Diabetes 30:64-69.
- Breckon, G.J. 1979. Studies in Cnidoscolus (Euphorbiaceae). Brittonia
- Brise, H. and L. Hallberg. 1962. Effect of ascorbic acid on iron absorption.
Acta Med. Scand. Suppl. 171:51-58.
- Diaz-Bolio, J. 1975. Chaya (Cnidoscolus chayamansa, Euphorbiaceae), a
marvellous food (in spanish). Tierra 30:407-408, 427-428.
- FAO. 1987. Promoting under-exploited food plants in Africa.: A brief for policy
markers. Food and Agriculture Organization, Food Policy & Nutrition Div.,
- Grubben, G.J.H. 1978. Tropical vegetables and their genetic resources. Int.
Board Plant Genetic Resource, FAO-UN, Rome Italy.
- Harris, R.S. and H.E. Munsell. 1950. Edible plants of Central America. J. Home
- Hodges, R.E., H.E. Sauberlich, J.E. Canham, D.L. Wallace, R.B. Rucker, L.A.
Mejia, and M. Mohanram. 1978. Hematopoietic studies in vitamin A deficiency.
Am. J. Clin. Nutr. 31:876-885.
- Levander, O.A. 1990. Fruit and vegetable contribution to dietary mineral intake
in human health and disease. HortScience 25:1486-1488.
- Martin, F.W., and R. Ruberte. 1978. Chaya, Cnidoscolus chayamansa
includes composition and nutritional value, culture in Puerto Rico. In:
Vegetables of hot humid tropics. USDA, ARS. New Orleans, LA.
- McVaugh, R. 1944. The genus Cnidoscolus: generic limits and intrageneric
groups. Bul. Torrey Bot. Club 71:457-474.
- Munsell, H.E., L.O. Williams, L.P. Guild, C.B. Troescher, G. Nightingale, and
R.S. Harris. 1949. Composition of food plants of Central America. Food. Res.
- NAS. 1975. Chaya. p. 45-48. In: Underexploited tropical plants with promising
economic value. National Academy of Science, Washington, DC.
- National Research Council. 1989. Diet and health. National Academy Press,
- Peregrine, W.T.H. 1983. Chaya (Cnidoscolus aconitifolius): A potential
new vegetable crop for Brunei. Tropical Pest Manag. 29:39-41.
- Rowe, L. 1994. Plant guards secret of good health. Valley Morning Star. Sept.
4, p. A1, A12.
- Searle, P.L. 1974. Automated colorimetric determination of ammonium in soil
extracts with "Technicon Autoanalyzer II" equipment. New Zealand J. Agr. Res.
- USDA. 1984. Agricultural handbook. p. 8-11. USDA, Washington, DC.
- Yang, Y.H. 1979. Tropical home gardens as a nutritional intervention. p.
417-436. In: G.E. Inglett and G. Charalambous (eds.), Tropical food chemistry
and nutrition, Academic Press, New York.
*Sincere appreciation is extended to Dr. Steven Lukefahr, Associate Professor,
Department of Animal and Wildlife Sciences, Texas A&M University-Kingsville
for supplying the rabbits and to Dr. Mo Enigbokan, Associate Professor of
Pharmacology, College of Pharmacy and Health Sciences, Texas Southern
University, Houston, Texas for verifying and giving helpful advice on the
Table 1. Comparisons of nutritional compositions of leaves of "chaya"
(Cnidoscolus chayamansa McVaughn) and spinach (Spinacia oleraceae L.) per 100 g fresh weight.
zData for spinach were obtained from the USDA (1984).
|Component ||chaya ||spinachz|
|Water (%) ||85.3 ||90.7|
|Protein (%) ||5.7 ||3.2|
|Fat (%) ||0.4 ||0.3|
|Crude fiber (%) ||1.9 ||0.9|
|Total CHO (%) ||4.2 ||3.8|
|Ash (%) ||2.2 ||1.8|
|Calcium (mg/100g) ||199.4 ||101.3|
|Phosphorus (mg/100g) ||39.0 ||30.0|
|Potassium (mg/100g) ||217.2 ||146.5|
|Iiron (mg/100g) ||11.4 ||5.7|
|Ascorbic acid (mg/100g) ||164.7 ||48.1|
|Carotenoids (mg/100g) ||0.085 ||0.014|
|Average nutritive valuey ||14.94 ||6.38 |
yAverage nutritive value according to Grubben emprical formula
Table 2. Effect of Cnidoscolus chayamansa leaf extract ("chaya"
tea) on blood glucose levels of non-diabetic and streptozoctocin-induced
||Blood glucose level (mg/dL)z|
| ||Non-diabetic ||Diabetic|
|Time (h) ||water ||"chaya" ||water ||"chaya"|
|0.0 ||87±3.1 ||85±2.5 ||112±8.3 ||118±13.2|
|1.0 ||86±2.7 ||91±3.9 ||138±4.6 ||114±7.3|
|2.0 ||87±2.6 ||99±4.3 ||143±6.4 ||103±8.7|
|3.0 ||87±3.1 ||82±1.6 ||139±8.0 ||96±9.3|
|4.0 ||88±3.0 ||85±2.1 ||153±6.3 ||92±5.8|
|5.0 ||87±4.7 ||84±4.2 ||158±7.4 ||89±3.6|
|6.0 ||87±3.1 ||82±2.7 ||162±9.0 ||87±2.7|
Fig. 1. A potted chaya plant. The young leaves and shoots are edible
after being boiled in water.
Fig. 2. Proximate fat, protein, carbohydrate and crude fiber
compositions of raw and cooked chaya leaves.
Fig. 3. Proximate mineral macronutrient (calcium, phosphorus, potassium
and iron) compositions of raw and cooked chaya leaves.
Last update August 24, 1997