From the book
Fruits of Warm Climates
by Julia F. Morton
White Sapote
Casimiroa edulus Llave. RUTACEAE
The genus Casimiroa of the
family Rutaceae was named in honor of Cardinal Casimiro Gomez de
Ortega, a Spanish botanist of the 18th Century*. It embraces 5 or 6
species of shrubs or trees. Of these, 3 shrubby species, C. pubescens Ramirez, C. pringlei Engl. and C. watsonii Engl., are apparently confined to Mexico and have received scant attention. An additional species, C. emarginata Standl. & Steyerm., was described in 1944, based on a single specimen in Guatemala. It may be merely a form of C. sapota, below.
Of
the 3 larger-growing forms, the best known is the common white sapote,
called zapote blanco by Spanish-speaking people, abché or ahache by
Guatemalan Indians, and Mexican apple in South Africa, and widely
identified as C. edulis Llave & Lex. The matasano (or matazano), C. sapota Oerst., is often not distinguished from C. edulis
in the literature and the name matasano has been applied to other
species in various localities. The woolly-leaved white sapote, known to
the Maya as yuy and set apart in Guatemala as matasano de mico, has
been commonly considered a distinct species, C. tetrameria Millsp., but it may be only a variant of C. edulis.
| Fig.
48: A seedless white sapote, natural size, photographed by Dr. David
Fairchild at Orange, California, in October 1919. In his notes
accompanying the picture in Inventory of Seeds and Plants Imported, No.
60, he says: "It is not rare for trees of this species...may often be
due to defective pollination." (Bureau of Plant Industry, United States
Department of Agriculture) |
Description White
sapote trees range from 15 to 20 ft (4.5-6 m) up to 30 to 60 ft (9-18
m) in height. They have light-gray, thick, warty bark and often develop
long, drooping branches. The leaves, mostly evergreen are alternate,
palmately compound, with 3 to 7 lanceolate leaflets, smooth or hairy on
the underside. The odorless flowers, small and greenish-yellow, are 4-
or 5-parted, and borne in terminal and axillary panicles. They are
hermaphrodite or occasionally unisexual because of aborted stigmas. The
fruit is round, oval or ovoid, symmetrical or irregular, more or less
distinctly 5-lobed; 2 1/2 to 4 1/2 in (6.25-11.25 cm) wide and up to 4
3/4 in (12 cm) in length; with thin green, yellowish or golden skin
coated with a very thin bloom, tender but inedible; and creamy-white or
yellow flesh glinting with many tiny, conspicuous, yellow oil glands.
The flavor is sweet with a hint or more of bitterness and sometimes
distinctly resinous. There may be 1 to 6 plump, oval, hard, white
seeds, 1 to 2 in (2.5-5 cm) long and 1/2 to 1 in (1.25-2.5 cm) thick,
but often some seeds are under-developed (aborted) and very thin. The
kernels are bitter and narcotic. C. edulis
has leaves that are usually composed of 5 leaflets, glabrous to
slightly pubescent on the underside, and 5-parted flowers. The fruit is
somewhat apple-like externally, generally smooth, fairly symmetrical
and 2 1/2 to 3 in (6.25-7.5 cm) wide. C. sapota
is very similar but the leaves usually have only 3, somewhat smaller,
leaflets. The woolly-leaved white sapote usually has 5 leaflets, larger
and thicker than those of C. edulis
and velvety-white on the underside, and all the parts of the flowers
are in 4's. The fruits are usually 4 to 4 1/2 in (10-11.25 cm) wide,
ovoid, irregular and knobby, with rough, pitted skin, and there are
often gritty particles in the flesh.
Origin and
Distribution The
common white sapote occurs both wild and cultivated in central Mexico.
It is planted frequently in Guatemala, El Salvador and Costa Rica and
is occasionally grown in northern South America, the Bahamas, West
Indies, along the Riviera and other parts of the Mediterranean region,
India and the East Indies. It is grown commercially in the Gisborne
district of New Zealand and to some extent in South Africa.
Horticulturists in Israel took serious interest in white sapotes around
1935 and planted a number of varieties. The trees grew well and
produced little in the coastal plain; bore good crops in the interior
and commercial prospects seemed bright but the fruit did not appeal to
consumers and was too attractive to fruit flies. White sapotes have not
done well in the Philippines. The common species was introduced into
California by Franciscan monks about 1810, and it is still cultivated
on a limited scale in the southern part of that state. In Florida, it
was first planted with enthusiasm. Today it is seldom seen outside of
fruit tree collections. Of course, many of the trees planted have been
seedlings bearing fruits of inferior size and quality, but even the
best have never attained popularity in this country. C. sapota
is wild in southern Mexico and Nicaragua, commonly cultivated in Oaxaca
and Chiapas. The woolly-leaved white sapote is native from Yucatan to
Costa Rica and has not been widely distributed in cultivation.
According to Chandler, the fruits are objectionably bitter in
California. In southern Florida, the woolly-leaved is sometimes planted
in preference to C. edulis. White
sapote trees often are grown strictly as ornamentals in California.
They are planted as shade for coffee plantations in Central America.
Varieties Clonal selections
were made in California from about 1924 to 1954, and several also in
Florida. Some of these may actually be chance hybrids. A surprising
number have been named and propagated: 'Blumenthal', 'Chapman',
'Coleman', 'Dade', 'Flournoy', 'Galloway', 'Gillespie', 'Golden' or
'Max Golden', 'Johnston's Golden', 'Harvey', 'Lenz', 'Lomita',
'Maechtlen', 'Maltby' or 'Nancy Maltby', 'Nies', 'Page', 'Parroquia',
'Pike', 'Sarah Jones', 'Suebelle', or 'Hubbell', 'Walton', 'Whatley',
'Wilson', 'Wood', 'Yellow'.
'Coleman'–was
one of the first named in California; fruit is oblate, somewhat lobed,
furrowed at apex; to 3 in (7.5 cm) wide; skin is yellow-green; flesh of
good flavor (22% sugar) but resinous; seeds small. Fruit ripens from
late fall to summer. Tree somewhat dwarf; leaflets small and tend to
twist. Difficult to propagate. 'Dade'–grown
at the Agricultural Research and Education Center, Homestead, Florida
from a seed of a selected fruit of a local seedling tree. It was
planted in 1935 and fruited in 1939. Round; skin golden-yellow tinged
with green, thin; flesh of good, non-bitter flavor. There are 4 to 5
seeds. Ripens in June-July. The tree is low-growing and spreading, with
smooth leaflets. 'Gillespie'–originated
in California; fruit is round, 3 in (7.5 cm) wide; skin is light-green
with russet cheek, fairly tough, rough; flesh is white, of very good
flavor. Tree is prolific bearer. 'Golden',
or 'Max Golden'–woolly-leaved; fruit conical, depressed at apex; up to
4 1/2 in (11.25 cm) wide; skin yellow-green, fairly tough; flesh has
strong flavor, somewhat bitter; few seeds. 'Harvey'–originated
in California; round; 3 1/2 in (9 cm) wide; skin smooth, yellow-green
with bright orange cheek; flesh cream-colored to pale-yellow; not of
the best flavor. Tree is a prolific bearer. 'Maechtlen'–named
for the parent, an old tree on property owned by the Maechtlen family
in Covina, California. Propagated by budding and sold by nurserymen in
the 1940's. 'Maltby', or
'Nancy Maltby'–originated in California; round, faintly furrowed,
blunt-pointed at apex, base slightly tapered; large; skin yellow-green,
smooth, of good flavor but slightly bitter. Tree bears well. 'Parroquia'–originated
in California; oval, 2 1/2 in (6.25 cm) wide, 3 in (7.5 cm) long; skin
yellow-green, smooth, thin; flesh ivory, of very good flavor. A fairly
prolific bearer. 'Pike'–originated
in California; rounded or oblate, slightly 5-lobed; to 4 in (10 cm)
wide; skin green, very fragile; flesh white to yellowish, of rich,
non-bitter, flavor. The tree bears regularly and heavily in California
and South Africa. 'Suebelle',
or 'Hubbell'–originated in California; round; medium to small; skin
green or yellowish-green; of excellent flavor (22% sugar). Tree is
precocious and blooms and fruits all year. Fairly widely planted in
California. 'Wilson'–originated
in California; round to oblate; medium to large; skin smooth, medium
thick; flesh of high quality and excellent flavor. Fruit ripens in fall
and winter or more or less all year. Tree bears heavily and has been
rather widely planted in California. 'Yellow'–originated
in California; oval with pointed apex, furrowed; skin is bright-yellow
and fairly tough; flesh is firm. Fruit keeps well. Tree bears regularly
and heavily in California.
Pollination There is a great
variation in the amount of pollen produced by seedlings and grafted
cultivars. Some flowers bear no pollen grains; others have an
abundance. Sterile pollen or lack of cross-pollination are suggested
causes of aborted seeds and heavy shedding of immature fruits. In
Florida, flowers of some heavy-bearing, double-cropping, trees have
been observed so heavily worked by bees that their humming is heard
several feet away.
Climate The white sapotes can be classed as subtropical rather than tropical. C. edulis
is usually found growing naturally at elevations between 2,000 and
3,000 ft (600-900 m) and occasionally in Guatemala up to a maximum of
9,000 ft (2,700 m) in areas not subject to heavy rainfall. In
California, light frosts cause some leaf shedding but otherwise do not
harm the tree. Mature trees have withstood temperature drops to 20º F
(-6.67º C) in California and 26º F (-3.33º C) in Florida without injury. The
trees prosper near the coast of southern California where the mean
temperature from April to October is about 65º F (18º C). They do
poorly and often fail to survive further north near San Francisco where
the mean temperature for the same period is 57º to 58º F (13.89º-14.44º
C). The woolly-leaved is somewhat less hardy than the common white
sapote.
Soil As long as there is
good drainage, the trees will do very well on sandy loam or even on
clay. In California, some of the early plantings were on light,
decomposed granite soil, and they were fruitful for many years. In
Florida, the trees grow and fruit well on deep sand and on oolitic
limestone, though, on the latter, they may become chlorotic. They are
fairly drought-resistant.
Propagation White sapotes
are commonly grown from seeds and seedlings usually begin to bear in 7
or 8 years. Grafting is a common practice in California and Florida in
midsummer. Seedlings of 'Pike', being vigorous growers, are preferred
as rootstock. Shield-budding and side-grafting in spring onto stocks up
to 3/4 in (2 cm) thick give good results. Cleft grafts and slot grafts
are made on larger rootstocks and when topworking mature trees. Grafted
trees will start bearing in 3 or 4 years. Commercial growers in New
Zealand have had success with air-layers. Cuttings are very difficult
to root.
Culture In California, the
young trees are cut back to 3 ft (0.9 m) when planted out, in order to
encourage low-branching. As the branches elongate, some pruning is done
to induce lateral growth. Fertilizer formulas should vary with the
nature of the soil, but, in general, the grower is advised to follow
procedures suitable for citrus trees. Many white sapote trees have
received little or no care and yet have been long-lived. One of the
original trees in Santa Barbara, California, was said to be over 100
years old in 1915.
Season In the Bahamas, the
fruits ripen from late May through August. In Mexico, flowering occurs
in January and February and the fruits mature from June to October. In
Florida there is usually just a spring-summer crop, but a heavy-bearing
woolly-leaved tree in Miami blooms in December, fruits in the spring,
blooms again and produces a second crop in the fall. In California,
'Pike' and 'Yellow' bloom in the spring and again in late summer and
fall, the fruits from late blooms maturing gradually over the winter.
'Suebelle' blooms for 6 to 8 weeks in spring and again in midsummer and
fruits ripen in September and October.
Harvesting Mature fruits
must be clipped from the branches leaving a short piece of stem
attached. This stub will fall off naturally when the fruits become
eating-ripe. If plucked by hand, the fruits will separate from the stem
if given a slight twist but they will soon show a soft bruised spot at
the stem-end which quickly spreads over much of the fruit, becoming
watery and decayed. The fruits must be handled with care even when
unripe as they bruise so easily and any bruised skin will blacken and
the flesh beneath turns bitter. If picked just a few days before fully
ripe and ready to fall, the fruits turn soft quickly but they can be
picked several weeks in advance of the failing stage and most will
develop full flavor. 'Pike', however, if picked a month early, will
take 2 weeks to ripen and will be substandard in flavor. Fruits that
have ripened on hand will keep in good condition in the home
refrigerator for at least 2 weeks. Fruits from commercial orchards are
graded for size, wrapped individually to retard full ripening, packed
in wooden boxes, and well-padded for transportation under refrigeration.
Pests and
Diseases The
white sapote has few natural enemies but the fruits of some cultivars
are attacked by fruit flies. Black scale often occurs on nursery stock
and occasionally on mature trees in California.
Food Value Within its native
range, the white sapote is commonly eaten out-of-hand. The flesh of
ripe fruits may be added to fruit cups and salads or served alone as
dessert, but it is best cut into sections and served with cream and
sugar. Sometimes it is added to ice cream mix or milk shakes, or made
into marmalade. Even in their countries of origin, where the fruits may
at times appear in markets, their repute is due largely to a belief in
their therapeutic value, while, at the same time, there prevails a fear
that over-indulgence may be harmful. The epithet "matasano"
(interpreted as "kill health") has a sinister connotation. Dr. J.B.
Londoño, in his Frutas de Antioquia, published in Medellin, Colombia,
in 1934, referred to the white sapote as disagreeable and indigestible.
Some years ago in Central America there were unsuccessful efforts to
manufacture from the pulp an acceptable preserve. In processing trials
at the Western Regional Research Laboratory of the United States
Department of Agriculture, Albany, California, technologists decided
that white sapotes; are not suitable for either canning in sirup or
freezing as a puree.
Food
Value Per
100 g of Fresh Pulp* |
Moisture
|
78.3 g |
Protein |
0.143 g |
Fat |
0.03 g |
Fiber |
0.9g |
Ash |
0.48g |
Calcium | 9.9 mg | Phosphorus | 20.4 mg | Iron | 0.33 mg | Carotene | 0.053 mg | Thiamine | 0.042 mg | Riboflavin | 0.043 mg | Niacin | 0.472 mg | Ascorbic Acid | 30.3 mg | *According
to analyses made in El Salvador |
|
As bearers of edible fruits, the white sapotes, despite their
prolificacy, will doubtless continue to occupy the minor position which
they now hold in subtropical horticulture.
Toxicity The seed is said to be fatally toxic if eaten raw by humans or animals.
Other Uses
Seeds: In 1959, Dr. Everette
Burdick, Consulting Chemist, of Coral Gables, Florida, made several
extractions from the kernels, securing small amounts of needle-like
yellow crystals. From one process, a yellow resinous mass resulted
which functioned as an attractive and lethal bait for American
cockroaches, having the advantage of killing on the spot rather than at
some distance after ingestion of the poison. The United States
Department of Agriculture's Agricultural Handbook 154, Insecticides
from Plants, mentions no experiments with Casimiroa seed extracts but
reports that extracts from branches and leaves of C. edulis are non-toxic to both American and German roaches.
Wood:
The wood is yellow, fine-grained, compact, moderately dense and heavy,
medium strong and resistant, but not durable for long. It is
occasionally employed in carpentry and for domestic furniture in
Central America.
Medicinal
Uses: The
ancient Nahuatl name for the fruits, "cochiztzapotl", is translated
"sleepy sapote" or "sleep-producing sapote", and it is widely claimed
in Mexico and Central America that consumption of the fruit relieves
the pains of arthritis and rheumatism. This belief may stem only from
the oft-quoted statement to this effect by Dr. Leopoldo Flores in
Manual Terapeutica de Plantas Mexicanas, published in 1907, although
the Mexican National Commission has received frequent reports of
anti-arthritic, anti-rheumatic effects from physicians and their
patients. The eminent Francisco Hernandez, in his writings during
the period 1570-1575 (translated and published as Rerum Medicarum Novae
Hispaniae in 1651), noted that eating the fruit produced drowsiness. He
referred to the seeds as "deadly poison" but efficacious, when crushed
and roasted, in healing putrid sores. This vulnerary use of the seeds
is cited in the obsolete Farmacopea Mexicana, where the fruit is
mentioned as a vermifuge. For many years, extracts from the leaves,
bark, and especially the seeds have been employed in Mexico as
sedatives, soporifics and tranquilizers. The narcotic property of
the seeds was first identified as an alkaloid by Dr. Jesus Sanchez of
Mexico in his thesis, Breve estudio sobre la almendra del zapote
blanco, in 1893; and, in 1898, it was made the subject of chemical
study by an especially appointed commission. One of the investigators,
Alfonso Altimirano, reported the isolation of a glucoside as a pale
yellow, amorphous mass, at first sweet but with a prolonged bitter
aftertaste. White sapote derivatives were among the medicinal plant
products displayed at the St. Louis Exposition in 1904 and explained in
the slender book, Materia Medica Mexicana: A Manual of Mexican
Medicinal Herbs, prepared by the Mexican National Commission for that
occasion. In 1900, a quantity of white sapote seeds was sent from
Mexico to F.H. Worlee & Co., in Hamburg, Germany, with an
accompanying explanation that both the fruit and the seeds possessed
sleep-inducing principles but without the undesirable after-effects of
opium. This material came to the attention of W. Bickern. He proceeded
to work on the seeds, from which he obtained a substance which he
called an alkaloidal glycoside, casimirin. In France, several
investigators confirmed the narcotic nature of the seeds. Subsequently,
Frederick Power and Thomas Callan of the Wellcome Chemical Research
Laboratories in London, declared that, though they isolated 6
substances including 2 alkaloids, casimiroine and casimiroedine, there
was "no evidence of the presence of a definite glucoside or a so-called
glucoalkaloid ...and physiological tests conducted with animals
...likewise failed to confirm . . . reported hypnotic or toxic
properties." Meanwhile, the seed extracts, in liquid, capsule, or
tablet form, continued in use in Mexico, one product bearing the trade
name "Rutelina". In 1934, José de Lille proceeded to test the
effect on blood pressure of dogs. He found a dose of .20 g per kilo of
animal weight to be definitely hypotensive. A large dose (1 g)
administered to a dog weighing 11 lbs (5 kg) produced a drastic
lowering of blood pressure which persisted even after a brief rise
induced by injecting adrenalin. In 1936, M. Mendez described the
preparation of a tincture of "a clear yellow color with neither special
odor nor taste" which produces "a state of depression in the entire
nervous system, especially in the sensory sphere, and sleep." Dr.
Faustino Miranda reported that an infusion of the leaves of Casimiroa
sapota is used for similar purposes, and he assumed that this species
has the same properties as C. edulis. According to Materia Medica
Mexicana, the extracts from the leaves and bark are half as strong as
those from the seeds and can be safely administered to children. In
Costa Rica, the leaf decoction is taken as a treatment for diabetes. In
1956, four chemists, F. Kinel, J. Rosso, O. Rosenkranz and F.
Sondheimer, on the staff of the Mexican branch of the pharmaceutical
company, Syntex, undertook chemical studies of the seeds. They did not
find the "gluco-alkaloid" casimirin, but isolated 13 substances, 6 of
which coincided with those reported by Power and Callan. One of these,
casimirolid, was later found by F. Sondheimer, A Meisels and F. Kinel,
to be identical with obacunone, an attribute of citrus oil. Of the 7
additional compounds, one palmitamide, had not previously been noted in
the plant kingdom. Another, N-benzoyltyramine, they suggested might
have much to do with the reputed potency of the seed, for tyramine is
one of the active principles of ergot (is also found in mistletoe and
thistle) and is well known for its physiological action. The main
alkaloid of the seeds, casimiroedine, representing 0.143%, was
crystallized in the form of needles. Investigations of the bark from
the trunk and roots of C. edulis were undertaken for Syntex by J.
Iriarte, F. Kinel, O. Rosenkranz and F. Sondheimer. No casimiroedine
was found but 12 substances were identified, only 2 of which, zapotin
and casimiroin, occur in the seeds. The root bark contained .22% of the
latter, while the seeds yielded only 0.0076%. In 1957, Meisels and
Sondheimer announced that one of the bark alkaloids, edulein, which
they had considered new, is identical with an alkaloid found in the
bark and leaves of Lunaria amara Blanco, a citrus relative of Malayan
origin. In 1958, R.T. Major and F. Dürsch, of the Cobb Chemical
Laboratory, University of Virginia, working under a grant from Merck
& Co., isolated from C. edulis seeds a compound which they
identified as Na, Na-dimethy1histamine, formerly found in nature only
in the sponge, Geodia gigas. J.S.L. Ling, S.Y. P'an and F.A. Hockstein,
of Chas. Pfizer & Co. Research Laboratories, Brooklyn, New York, in
experimental work with this compound in rabbits, dogs and cats,
observed strong vasodepressive action. Dr. Hockstein suggested that all
of the hypotensive properties and at least part of the sedative and
pain-relieving qualities could be attributed to this compound, which
"is not considered acceptable in man". In early July of 1960, the
writer furnished approximately 2 bushels of largely overripe, fallen
fruits of C. edulis and the woolly-leaved white sapote to Delta
Pharmaceuticals of Hialeah, Florida. They readily extracted from the
seeds a soporific substance, 50 mg of which, taken by humans, induced
sound sleep within 2 hours, with no apparent ill effects. The extract
also acted as a narcotic on goldfish. The following statement
(translated from Spanish) is made in a communication received in 1961
from the Sección Administrativa, Dirección de Control de Medicamentos,
Secretaria de Salubridad y Asistencia, Mexico City: "In Mexico, the
white sapote is not used other than in folk medicine and not in any way
by pharmacists nor doctors; neither is it an official drug in the
Pharmacopoeia". In India, extensive studies have been made of the
seeds, roots and bark, which contain histamine derivatives with strong
hypotensive activity, as well as furoquinoline alkaloids and
2-quinolones and 4-quinolones, including edulein, edulitin, edulinine
and casimiroin. Also present are coumarins, flavonoids, and limonoids,
including zapoterin, zapotin, zapotinin, casimirolid, deacetylnomilin,
and 7-a-obacunol. Leaves and twigs yield isoplimpinellin (diuretic) and
n-hentriacontane (anti-inflammatory).
| Fig. 49: The common white sapote (Casimiroa edulis) (left) and the woolly-leaved white sapote, often called C. tetrameria (right). The latter may be only a variant of C. edulis. |
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