ABSTRACT
Aloe vera (L.) Burm. F. (= Aloe barbadensis Miller) known as "the plant of
immortality" in ancient Egypt is used in phytotherapy as moisturizer, antibacterial,
antifungal, antiviral and antioxidant. In Argentina it grows in the form adventitious or
cultivated, Aloe arborescens Mill., Aloe saponaria Haw. and Aloe ciliaris Haw.
(Aloaceae).
In order to contribute to the identification of the drug plant the morphoanatomi
characterization of the leaf was carried out.
These species were studied with optical microscopy and scanning electron
microscopy and the histochemical characteristics were studied in order to identify
the active compounds.
Morphoanatomical characteristics of these species were determined through lineal
and proportional (stomatal index) parameters.
Perfect None
Main ideas. Cognates
False
Aloe vera, also known as Aloe barbadensis Miller, is used Cognates
in phytotherapy for its moisturizing, antibacterial, Real
Cognates
antifungal, antiviral, and antioxidant properties.
suffixes
The plant grows in Argentina in adventitious or
prefixes
cultivated form, along with other species like Aloe verbs -------------
arborescens Mill., Aloe saponaria Haw., and Aloe ciliaris adjectives adjectives
Haw. (Aloaceae).
The morphoanatomical ingcterization of the leaf was
conducted to contribute to the identification of the drug
plant.
INTRODUCTION
Aloe vera was known as "the plant of immortality" in ancient Egypt, also called the "biblical plant" due to
the number of times it is mentioned in the Old and New Testaments. It is reported that Nicodemus used a
mixture of Aloe vera and myrrh to embalm Jesus. In Roman times, the leaves were used, both the colorless
gel and the mesophyllous gel (Morton, 1961; Crosswhit, 1984). In our country, popular use replaces other
species of the Aloe genus with the same therapeutic and
cosmetic purposes. From this, it is essential to differentiate the species in circulation through the
morphoanatomical study of each of them in comparison with A. vera to determine the taxonomic status of
the species used. Plants belonging to the genus Aloe L. (1753) are currently included in the family Aloaceae
(Van Wyk & Smith, 1996). They are a group of monocotyledonous, perennial plants, with succulent leaves,
inflorescences in panicles or racemes, with liliform flowers. It is a widespread family, especially abundant in
tropical and subtropical regions, with enormous economic and medicinal importance (Carter, 1994; Agra et
al., 2007 and 2008; Oliveira et al., 2007; Silveira et al., 2008).
The origin of the genus Aloe has been discussed by several researchers (Cowling, 1982) suggesting that this
group of plants originated in the Eastern Cape of southern Africa (Holland, 1978) adding that the ancestor of
these plants had its origin in the lands highlands of that African region, time before the invasion of the sea
into the Mozambique Channel, in the middle of the Cretaceous period. Smith & Steyn (2004) argue that the
genus Aloe was fully developed in the early Jurassic and also provide evidence that the ancestor of this
genus was a plant probably about 150 mm tall. From this it follows that some authors consider shorter
plants as the ancestral ones of their taller congeners.
From the cytogenetic point of view, several researchers have studied the karyotypes of the Aloaceae family
(Valdés, 1997; Stack & Anderson, 2001; Belmont, 2002; Pavlova & Zakian, 2003) reiterating that this group
of plants is an example of great stability. chromosomal, due to the observation of a constant bimodal
karyotype, 2n = 14.
MATERIAL AND METHODS
Samples were obtained from the leaves of the same specimen. Specimens of the species are preserved in
the Carlos Spegazzini Herbarium of Botany and Pharmacognosy (LPE) of the Faculty of Exact Sciences of
the National University of La Plata (UNLP). A. arborescens: Leg. Stella M. Carpano Argentina, Bs. As. La
Plata, No. 928, 948,951, (LPE); A. ciliaris: Leg. M. T. Castro, Argentina, Bs. As., La Plata, No. 944, (LPE); A.
saponaria: Leg. Etile Spegazzini, Argentina, Bs. As.
Gonnet, Nº 929, 949,950 (LPE).
Leaf cuts were carried out with a Ranvier microtome from fresh material. Histochemical tests were performed with
Observations were made with an Olympus CH Optical Microscope (OM) and illustrations were made using an
Iroscope drawing tube.
Regarding the techniques used for observation with the Scanning Electron Microscope (SEM), fresh pieces
of leaves were washed with distilled water - detergent and fixed in 96º ethanol, distilled water, formalin and
glacial acetic acid (F.AA .) for 48 hours. Finally, under the stereoscopic microscope, a small piece of the
material was sectioned, dried with filter paper and mounted on a stage covered with double-sided adhesive
tape, finishing the drying with the point light of the stereoscopic microscope.
The observations and photomicrographs were carried out with a Jeol JSM-T 100 from the SEM Service of the La
Plata Museum, UNLP, Argentina.
Botanical description - endomorphological characters
Aloe vera L
Acaulescent or short-stemmed plant. Rosette leaves, spreading or ascending, lanceolate-attenuated
towards the apex, up to 40 - 50 cm long and 6 - 8 cm wide at the base, green, with toothed margins 2 - 3
mm long and 1 - 1.5 cm apart. Simple or branched racemose inflorescence. Perianth 2 - 3 cm long, yellow
(Reynolds, 1950)
Aloe saponaria (Ait.) Haw
Acaulescent or short-stemmed plant. Rosette leaves, spreading or slightly recurved, up to 35 cm long and 8 - 12 cm
Aloe ciliaris Haw
Decumbent plant with a long, very flexible, sarmentous stem. Leaves linear-lanceolate, long acuminate, spreading t
A loe a rborescens Mill
Plant with upright, well-developed stem. Rosette leaves, erectly spreading to spreading deflexed, lanceolate-
acuminate 50 - 60 cm long, 5-7 cm wide at the base, dark green to bluish green with margins with forward-
curving teeth 3 - 5 mm long ,
5-20mm distance. Racemose inflorescence usually simple. Perianth 3.5 cm long, scarlet. (Reynolds, 1950)
(Figure 2).
RESULTS AND DISCUSSION
Endomorphological characters
Aloe vera L
Optical microscopy (Figure 4): The leaf sections show an epidermis, a homogeneous parenchyma and a
central region of colorless parenchyma between both vascular bundles. Epidermis of polygonal cells,
isodiametric in superficial view, covered by an ornamented and thick cuticle with waxes. Stomata sunken on
both sides. Homogeneous parenchyma with calcium oxalate raphides. Collateral vascular bundle, secretory
cells forming a cap on the phloem pole surrounded by a parenchymatic sheath.
Aloe saponaria (Ait.) Haw
Optical microscopy (Figure 4): The leaf sections show an epidermis, a homogeneous parenchyma, a central
region of colorless parenchyma and between both vascular bundles. Epidermis of polygonal, isodiametric
cells in superficial view covered by an ornamented and thick cuticle with wax. Stomata sunken on both
sides. Homogeneous parenchyma with calcium oxalate raphides. Collateral vascular bundle, secretory cells
forming a cap on the phloem pole surrounded by a parenchymatic sheath.
Scanning electron microscopy (Figure 6): Ornamentation of the cuticle with densely distributed and generally
fused granules. Wax flakes. Cell boundaries are not ornamented and when the cuticle is partially removed
they show a stria. Outer walls of flat epidermal cells. Margins of the subsidiary cells protusive with a non-
rectangular external ring, with convex longitudinal axes below is the substomatal cavity.
Aloe ciliaris Haw
Optical microscopy (Figure 4): The leaf sections show an epidermis, a homogeneous parenchyma, a central
region of colorless parenchyma and between both vascular bundles. Epidermis of elongated polygonal cells in
superficial view, covered by an ornamented, waxy cuticle. Stomata at the same level as the epidermal cells.
Homogeneous parenchyma with calcium oxalate raphides. Collateral vascular bundle, surrounded by a
parenchymatic sheath.
Scanning electron microscopy (Figure 7): Ornamentation of the cuticle with ribs that form a reticuloid design.
Contour of epidermal cells bordered by ribs, separated by a slight groove. In adjacent cells wax in the form of
irregular particles.
Stomata with an oval ring.
Aloe arborescens Mill
Optical microscopy (Figure 4): The leaf sections show an epidermis, a homogeneous parenchyma, a central
region of colorless parenchyma and between both vascular bundles. Epidermis of polygonal cells, elongated
in superficial view, covered by an ornamented and thick cuticle, with wax. Stomata sunken on both faces.
Homogeneous parenchyma with calcium oxalate raphides. Collaterally on the phloem pole is a cap of
colorless cells (4-6), surrounded by a parenchymatic sheath.
Scanning electron microscopy (Figure 8): Ornamentation of the cuticle formed by granules, tubercles, warts
and short ribs, almost parallel, the elements generally fuse together. Wax in the form of flakes. Ornate and
elevated contours of the epidermal cells in relation to the central cell area. Margins of the subsidiary cells
protrusive with an oblong ring, below is the substomatal cavity.
(Cowling, 1982) suggesting that this group of plants
originated in the Eastern Cape of southern Africa
(Holland, 1978) adding that the ancestor of these plants
It is reported that Nicodemus used
had its origin in the lands highlands of that African
a mixture of Aloe vera and myrrh to
region
embalm Jesus.
Aloe saponaria (Ait.) Haw
Aloe vera was known as "the plant of
Acaulescent or short-stemmed plant. immortality" in ancient Egypt, also
Rosette leaves, spreading or slightly MATERIAL AND METHODS
called the "biblical plant" Histochemical tests were performed
recurved with methylene blue to reveal mucilage
The adaxial side pale green to dark and 50% ammonia to reveal chemical
green, with numerous light oblong components such as aloin and
spots arranged in transverse rows, barbaloin. Observations were made
Aloe Vera
wavy or divided, abaxial side usually with an Olympus CH Optical
paler than the adaxial, without spots. Microscope (OM)
Aloe ciliaris Haw
Aloe vera L
Decumbent plant with a long, very
Aloe arborescens Mill
flexible, sarmentous stem. Leaves linear- Acaulescent or short-stemmed plant.
lanceolate, long acuminate, spreading to Simple or branched racemose
Plant with upright, well-developed
recurved inflorescence.
stem. Rosette leaves, erectly
Simple racemose inflorescence.
spreading to spreading deflexed
Racemose inflorescence usually
simple.
