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Journal of Medicinal Plants Research Vol. 5(7), pp. 1037-1045, 4 April, 2011
Available online at http://www.academicjournals.org/JMPR
ISSN 1996-0875 ©2011 Academic Journals
Review
Mayapple: A review of the literature from a horticultural
perspective
Muhammad Maqbool
Department of Horticulture, University College of Agriculture, Bahauddin Zakariya University, Multan, Pakistan.
E-mail: maqboolmsu@hotmail.com.
Accepted 5 January, 2011
Species of the Podophyllum genus contain important anti-cancer compounds: podophyllotoxin, -
peltatin, and -peltatin. A Podophyllum species found in India, Podophyllum emodi Wall. (Syn. P.
hexandrum Royale, Berberidaceae), has been over-harvested to meet pharmaceutical industry demand.
The Indian species P. emodi Wall, is considered an endangered species because the compound is
found in the roots and whole plant was harvested. On the other hand, American Mayapple is a
rhizomatous herbaceous perennial found in the wild throughout North America from Quebec and
Minnesota to Florida and Texas and source of compound is leaves. Commercial plantings of mayapple
have the potential to reduce harvest pressure on this species. In a review of the scientific literature, few
references about commercial production or field establishment were found. To begin to understand
mayapple as a horticultural crop, this review presents a summary of the plant’s botany, climate and
soils, growth and development, sexual and asexual propagation, pests and diseases, and medicinal
uses. Sixty references are listed.
Key words: American mayapple, Podophyllum peltatum, Podophyllum emodi, Podophyllum hexandrum,
podophyllotoxin, -peltatin, -peltatin, rhizome, field establishment.
INTRODUCTION
The American Mayapple (P. peltatum) has become well
known for containing anti-cancer, anti-viral, and anti-
mitotic compounds (Meijer, 1974; Bedow and Hatfield,
1982; Canel et al., 2000b). These compounds are lignans
found in podophyllin, a term used to describe ethanolic
extracts of the American Mayapple and other
Podophyllum species. Three lignans have been identified
with health-related activity: podophyllotoxin, -peltatin,
and -peltatin (Figure 1). Podophyllotoxin has anti-
cancer, anti-mitotic and immunostimulatory activities
(Kaplan, 1942; Loike et al., 1978; Pugh et al., 2001)
whereas - and -peltatin have purgative (laxative)
properties. Native Americans and other indigenous
people used these plants as purgatives and also for
treatment of genital warts and skin cancers (Krochmal et
al., 1969). It is important to mention, however, that all
parts of the mayapple plant are considered poisonous to
humans with the only exception thought to be the ripe
fruit.
P. peltatum and P. emodi are the major sources of
podophyllotoxin. Podophyllotoxin is used as the precursor
in the manufacture of the semi-synthetic derivatives
etoposide, teniposide, and etopophos. The United States
Food and Drug Administration approved these drugs for
the treatment of testicular and small cell lung cancer
(Foster, 1989). Since 1995, when the patent covering
these uses expired, the National Cancer Institute has
listed 190 clinical trials for etoposide in new cancer
therapies or as positive control (Ajani et al., 1999; Holm
et al., 1998; Ekstrom et al., 1998). Another compound,
known as CPH 82, is a semi-synthetic derivative of
podophyllotoxin and is in its third phase of clinical trials
for the treatment of rheumatoid arthritis (Lerndal and
Svensson, 2000). A highly purified preparation of
podophyllotoxin has been tested for the treatment of
psoriasis (Lender and Rosen, 1988). P. peltatum and P.
emodi are not the only sources of podophyllotoxin.
Similar lignans have been found in the roots and
1038 J. Med. Plant. Res.
Podophyllotoxin -Peltatin -Peltatin
Figure 1. Structures of three health related lignans found in mayapple.
rhizomes of P. pleianthum (Jackson and Dewick, 1985)
and P. versipelle (Broomhead and Dewick, 1990a). Yu et
al. (1991) isolated a new podophyllotoxin–type lignan, 4´-
demethylisopodophyllotoxin, from Dysosma versipellis
var. Tomentosa. Podophyllotoxin and related aryltetralin
lignans have also been reported in various genera such
as Linum, Hyptis, Teucrium, Nepeta, Jeffersonia,
Thymus, Thuja, and Juniperus (Broomhead and Dewick,
1990a; (Broomhead and Dewick, 1990b; Konuklugil,
1996; Kuhnt et al., 1994; Muranaka et al., 1998; San
Feliciano et al., 1989a; San Feliciano et al., 1989b).
Though podophyllotoxin has been reported in plants of
these genera, quantitative data is limited.
Commercial plantings will provide a consistent and high
quality product to the drug industry and may provide
opportunities for agricultural producers of high-value
specialty products. To meet pharmaceutical industry
demand, P. emodi is still harvested from the wild.
However, it is difficult to collect from the wild and to
properly supervise the harvest of a high quality product.
Furthermore, excessive harvest has resulted in a
significant decline of wild populations. Such decline has
been reported in India with P. emodi now considered an
endangered species (Foster, 1993). Commercial
plantings of mayapple have the potential to reduce
harvest pressure on this endangered species.
Findings reported by National Center for Natural
Products Research (NCNPR) at the University of
Mississippi support the potential of establishing field
plantings of mayapple for the commercial production of
podophyllotoxin. It was found that leaves of P. emodi
were a poor source of podophyllotoxin compared to the
traditional source from the rhizomes. In contrast, leaves
of P. peltatum contain relatively high levels of
podophyllotoxin (Canel et al., 2001; Moraes et al., 2001).
Podophyllotoxin content of P. peltatum leaves is lower
than that of P. emodi rhizomes but still enough to
consider P. peltatum leaves a potential commercial
source of the compound. NCNPR and USDA increased
the potential of using leaves as a commercial source by
patenting an easy and efficient water-based method to
extract lignans from mayapple tissue (Canel et al., 2000a;
Moraes et al. 2002).
BOTANY AND CLASSIFICATION
Common names for the American Mayapple are
Mandrake, Wild Lemon, Raccoon Berry, Wild Jalap,
Devil’s–apple, Hog Apple, Indian Apple, and Umbrella
Plant (Cornell Univ, 1976; Reader’s Digest Assoc., 1986).
In the southern U.S., it is often referred to as “Maypop.”
Mayapple is an erect herbaceous perennial 1½ to 2 feet
in height, with a solitary or forked stem topped with one
or two leaves that are palmately lobed and up to 12
inches wide (Figure 2a). The solitary, creamy white,
fragrant flowers vary from 2 to 3 inches across, and arise
in the v-shaped axil of the stem (Figure 2a). The
rhizomes grow close to the soil surface (Figure 2b).
Individual plants, or shoots, arise at each node of the
underground rhizome and form dense clonal communities
(Figure 2c). Mature fruits are yellow, 1½ to 2½ inches
long, ovoid and may contain up to 25 seeds, each in a
mucilaginous aril (Figure 2d). The seeds are dark brown,
oval, flattened, and tapered at the apex, with a dull brown
rough surface and an oval, inconspicuous hilum. As the
seeds age, they become wrinkled (Krochmal et al., 1974).
Pearce and Thieret (1993) described mayapple fruit as
green-yellow to yellow when ripe (mid to late summer),
many seeded, and about the size and shape of a hen’s
egg. They reported an average weight of 13.4 g per fruit,
with 34.3% of the total weight being made up of seeds
Maqbool 1039
Figure 2a. Mayapple plant showing a solitary flower on a forked stem.
Figure 2b. Mayapple rhizome.
and attached arils. According to their findings mayapple
fruit contains extremely high water contents (94.7%),
higher even than watermelon (92%), grapefruit (91%),
melons (90%) or papaya (89%).
Fifteen species of the Podophyllum genus have been
described, but most are now placed taxonomically in the
related genera of Dysosma and Sinopodophyllum. The
Podophyllum genus is placed in the Berberidaceae
family. Species in the Podophyllum genus can be difficult
to research because they have been moved from genus
to genus and have at times been renamed. For example,
P. emodi and P. hexandrum are synonyms. Older
manuscripts often refer to this species as P. hexandrum.
In addition, P. plieanthum and Dysosma plieantha are
synonyms. Chinese scientists separated the
Podophyllum genus from the Berberidaceae family and
created a new family, Podophyllaceae (Foster, 1989).
Much confusion still remains in that there are many
1040 J. Med. Plant. Res.
Figure 2c. Mayapple colony in the wild.
Figure 2d. Mayapple fruit.
suggestions for further rearrangements. For example,
one suggestion is to place the Podophyllum genus in a
subfamily, Podophylloideae (Heywood, 1993).
BIODIVERSITY IN POPULATIONS
Finding by NCNPR showed that podophyllotoxin content
of P. peltatum leaves varied by location (Moraes et al.,
2001). About 17 wild populations were sampled from
Illinois, Indiana, Missouri, North Carolina, Ohio and West
Virginia (Figure 3) with podophyllotoxin content ranging
from 1.1 to 56.0 mg⋅g-1. Eleven wild populations were
also sampled from Lafayette County, Miss. with
podophyllotoxin content ranging from almost 0 to 23.6
mg⋅g-1. After two years of cultivation in plastic containers,
accessions with low podophyllotoxin content remained
low while accessions with relatively high podophyllotoxin
Maqbool 1041
Map showing distribution of
mayapple in North America
Figure 3. Distribution of mayapple (Podophyllum peltatum) in North America (USA and
Canada). Adopted from USDA database.
content remained high. These results indicate that
podophyllotoxin content is a stable genetic trait rather
than an effect of location or environment. These results
also indicate that mayapple leaves harvested from the
wild may—or may not—produce acceptable yields of
podophyllotoxin. The implications of this research
indicate that genetic improvement of mayapple may be
possible by identifying, propagating, and genetically
manipulating high-yielding genotypes. In this same study,
a negative correlation was found between
podophyllotoxin content and peltatin content. Genotypes
with higher levels of podophyllotoxin had lower levels of
-peltatin and -peltatin. Similarly, Zheljazkov et al.,
(2009) collected American mayapple leaves from 37
mayapple colonies across 18 states indicated a
significant variation in podophyllotoxin, -peltatin, and -
peltatin content and the presence of chemotypes. Overall,
the concentrations of podophyllotoxin, -peltatin, and -
peltatin in the collected accessions ranged from below
detectable levels to 45.1, 47.3, and 7.0 mg·g–1 dry weight,
respectively. They also classified American mayapple
accessions into seven groups:
1) With very high concentration of podophyllotoxin
(greater than 20 mg·g–1) and no - or -peltatin;
2) High podophyllotoxin (greater than 10 mg·g–1) and no
-peltatin but trace amounts of –peltatin;
3) Medium podophyllotoxin (1 to 10 mg·g–1) and no - or
-peltatin;
4) Low podophyllotoxin (0.05 to 1 mg·g–1) and high -
peltatin;
5. Trace amounts of podophyllotoxin and high
concentration of -peltatin and -peltatin;
6. High -peltatin and trace amounts of podophyllotoxin or
–peltatin; and
7. High –peltatin and no podophyllotoxin or -peltatin.
The results from this study may contribute toward the
development of high podophyllotoxin containing varieties
of American mayapple and the development of a new
cash crop for farmers.
Sultan et al. (2010) narrated that that RAPD and
chemical markers are very useful tools to compare the
genetic relationship and pattern of variation among
different populations of Podophyllum hexandrum
collected from high altitude regions of North Western
Himalayas declared an endangered medicinal plants.
It has been observed that Podophyllotoxin and total
lignin contents of American mayapple at 0% shade were
significantly greater than those at 80% shade and shade
did not affect -peltatin content. However, contents of -
peltatin were greatest at 0% shade compared to the other
three shade treatments (Cushman et al., 2005). Crushing
injury drastically improved podophyllotoxin content of
1042 J. Med. Plant. Res.
American mayapple leaves when dried at 40°C within 24
h of harvest (Bedir et al., 2006). In contrast,
podophyllotoxin content was greatly reduced when dried
at room temperature at 15% relative humidity and 24°C.
However, Podophyllotoxin content was stable, with no
significant changes over time, when leaves were dried,
ground, and stored under different conditions for up to 60
days.
SOIL AND CLIMATE
P. peltatum is found in the wild, often in large colonies in
eastern North America from Quebec and Minnesota to
Florida and Texas (Meijer, 1974; Pearce and Thieret,
1993). The wide distribution of mayapple in the wild
shows that it can survive under a wide range of
conditions from the extreme below-zero winter
temperatures of northern climates to the high summer
temperatures of southern climates. Krochmal et al. (1974)
analyzed the soil of a typical forest mayapple habitat
located in the Daniel Boone National Forest, Jackson
County, Kentucky. The soil was defined as a typical
southern Appalachian cove soil with alluvial and colluvial
material. The analysis showed mineral element and
organic matter (OM) contents of 0.4-1.9 ppm P, 200-540
ppm Ca, 80-120 ppm Mg, 125-300 ppm K, 0.27-2.57 %
C, and 0.46-3.75 % OM. Soil samples were recently
collected from local mayapple populations in Lafayette
County, Miss. in the fall of 2000 and analyzed for soil
texture and mineral element (unpublished data). It was
found that these populations were growing in silt loam,
sandy loam, and loamy sand soils. The analysis showed
mineral element and OM contents of 4-25 ppm P, 53-430
ppm Ca, 15-109 ppm Mg, 21-85 ppm K, 102-212 ppm S,
and 1.41-2.94 % OM. The soils tested for pH in a range
of 4.7 to 6.0. According to Zheljazkov et al., (2009)
American mayapple was found to grow on various soil
types with a range of soil pH (4.6 to 7.6) and dissimilar
concentrations of phytoavailable soil nutrients. Tissue
zinc concentration was positively correlated to
podophyllotoxin, whereas soil and tissue phosphorus was
positively correlated to the concentration of -peltatin
GROWTH AND DEVELOPMENT
Plants grown from seed remain juvenile for 4 to 5 years.
During this time, shoots arise annually from a bud located
on the terminal end of an underground vertical stem.
After 4 to 5 years, plants then produce a single horizontal
rhizome. The rhizome continues to develop annually,
producing elongated internodes between nodes. Each
node is a complicated structure composed of a highly
compressed stem, a main bud that develops into the next
season’s growth, and many minor buds that any one of
them can develop and continue rhizome growth. Roots
develop predominately from rhizome tissue at the base of
the node. Roots can arise from the internodal tissue near
the terminal bud of the rhizome. For a review of
mayapple morphology, including seedlings, rhizomes,
nodes, and elongated internodes (Foerste, 1884; Holm,
1899).
A single shoot arises from each node of the rhizome.
Shoots are either asexual, producing a single vegetative
stem and leaf, or sexual, producing a single stem, two
leaves, and a solitary flower in a fork formed by the
petioles of the two leaves. A complex relationship of
environmental signals exists that determines whether any
particular node produces a sexual or asexual shoot. Prior
history of the node, whether it produced a sexual or
asexual shoot in the previous year, also greatly
influences the sexual or asexual status of the shoot. For
a thorough discussion of factors affecting not only sexual
or asexual shoot status but also rhizome branching, see
Geber et al. (1997).
Both types of growth, asexual and sexual, emerge in
early spring before trees produce leaves and then
senesce by midsummer. Watson and Lu (1999) observed
that several factors might influence the timing of shoot
senescence such as the current or future reproductive
status of the shoot, the past and current vigor of the
rhizome system, the genotype, and the environment to
which the plant was exposed. For example, sexual
shoots senesced later than asexual shoots. Sexual
shoots that produced fruit senesced later than sexual
shoots without fruit. Shoots arising from large rhizomes
senesced later than those from small rhizomes.
According to de Kroon et al. (1991) shoots that senesce
later produce longer and heavier rhizomes. Landa et al.
(1992) showed with 14C tracers that photoassimilates
were translocated to roots, rhizomes, and nodes at the
onset of leaf senescence. The stored carbohydrates are
then translocated to newly developing growing points the
following spring.
To explore the domestication of this species, Cushman
et al. (2005) harvested mayapple rhizome segments from
the wild and transplanted to raised beds using two mulch
types (pine bark or wheat straw), two depths of mulch (0
or 5 cm) and two planting depths (0 or 5 cm) of rhizome
segments and found that rhizome segments planted 0 cm
deep and covered with wheat straw mulch consistently
produced fewer shoots with less leaf area and dry mass
compared to other treatment combinations. They
recommended either bark or straw mulch for the purpose
of establishing field plantings in full sun as long as
rhizome planting depth is 5 cm.
SEXUAL PROPAGATION
The American Mayapple is described as self-
incompatible. Many researchers believe colonies of
mayapple in the wild are clonal populations comprised of
one genotype (Laverty and Plowright, 1988; Swanson
and Sohmer, 1976a). It is thought that an entire colony
may come from a single seedling. The seedling
eventually develops into a colony of plants with identical
genes. In contrast to this view, Policansky (1983) found
mayapple colonies comprised of more than one
genotype.
Laverty and Plowright (1988) observed a significant
increase in mayapple fruit and seed production when
populations of mayapple and Pedicularis canadensis
were located adjacent to each other and when insect
pollinators regularly visited both populations. This
increase in mayapple seed set by cross-pollination was
also observed with species of the genus Bombus
(Swanson and Sohmer, 1976b). They observed that intra-
population crosses in mayapple resulted in lower seed
set than inter-population crosses, thus adding to the
evidence that mayapple is at least partially self-
incompatible. Whisler and Snow (1992) found a 26-fold
increase in seed set by hand pollination in mayapple
compared to natural levels of pollination during one year
of observation and a 5-fold increase in the next. Rust and
Roth (1981) described that improper pollination is the
most important factor affecting seed set. They also
described other factors that could affect seed set, such
as flower abortion, immature fruit abortion, and failure of
fruits and seeds to be transported away from clonal
populations.
Krochmal et al. (1974) were unable to germinate
mayapple seeds even after finding 88 % of them viable
with a tetrazolium test. Badhwar and Sharma (1963) were
unsuccessful in germinating seeds of P. emodi even after
testing a wide variety of treatments to increase
germination. However, they found that seeds sown with
fresh mayapple fruit pulp germinated in 9 to 10 months.
Similar results were found in P. peltatum (Meijer, 1974).
Rust and Roth (1981) reported that turtle-ingested seeds
germinate faster and have higher probability of success
than non-ingested seeds of mayapple.
Asexual propagation
Troup, an investigator from India, was quoted as saying
that mayapple plants raised from rhizome cuttings “would
probably take at least 12 years to produce fair-sized
marketable rhizomes” (Badhwar and Sharma, 1963). The
investigator was also quoted as saying that plants raised
from seedlings would take even longer. Another
investigator, Chopra, was quoted as saying that
“rhizomes are fit to be collected for the market when they
are 2 to 4 years old.” Badhwar and Sharma (1963)
themselves experimented briefly with P. emodi rhizome
cuttings that were trimmed to ½ to 1 inch in length. From
34 to 98 % of the cuttings sprouted when planted from
May to July. Best results were obtained with cuttings
planted from late June to early July and with cuttings
Maqbool 1043
taken from the youngest portion of the rhizome.
It was narrated that fall planted propagules produced
greater leaf area and dry mass than spring or summer
planted propagules and Nt+N1 type of propagules
produced greater leaf area than Nx or Nt (Maqbool et al.,
2002; Cushman and Maqbool, 2005). Maqbool et al.,
(2004), further reported that two-node rhizome segments
of American mayapple performed better than one-node
propagules and segments chilled 60 days or longer
performed far better than those chilled for shorter
duration under greenhouse conditions.
Successful propagation of P. peltatum using in vitro
techniques has been reported (Moraes-Cerdeira et al.,
1998). Rooted buds and rooted plantlets were produced
from micro-propagated rhizome terminal buds and it was
found that rooted buds acclimated more readily to in vivo
conditions than rooted plantlets. In 2004, Moraes et al.,
found that survival of P. peltatum plantlets from In vitro
propagation was higher in a medium containg non-sterile
soil (NS)–sand (2:1 v/v) substrate than in Miracle–Gro
potting mix®-sand (2:1 v/v) with or without inocula of
arbuscular mycorrhiza (AM). Plantlets inoculated with
Entrophospora colombiana had a superior survival rate
(73%) than plantlets inoculated with Glomus mosseae,
Gigaspora ramisporophora or Scutellospora fulgida
(57%). Ex vitro G. ramisporophora inoculated plants
yielded more podophyllotoxin and related lignans than
the control, non-inoculated plants. Similar observation
was also reported by Kapoor et al. (2008).
PESTS
Mayapple is susceptible to rust. The causal organism is
Puccinia podophylli and it produces a non-systemic
infection that has two generations per year. The initial
infection occurs as shoots emerge in the early spring via
contact with soil that contains overwintering teliospores
(Whetzel et al., 1925). Bright orange lesions (aecia)
develop on leaves within two weeks. Aecia produce
airborne aeciospores that then re-infect the mayapple
leaves. Black lesions (telia) develop from which
overwintering teliospore are produced. The first
generation is the most harmful, since plants are damaged
early in their growth cycle. There is less damage during
the second generation, since telia development occurs in
the late spring just before normal leaf senescence.
According to Parker (1988), the demographic impact of
the disease in most mayapple colonies is minimal
because the plant has an effective morphological defense
that minimizes contact between spore-contaminated soil
and the emerging shoot in spring. Parker (1989)
observed however, higher levels of P. podophylli infection
on some non-native mayapple genotypes than on native
genotypes. Septotonia podophyllina infects mayapple, as
well as species of poplar and Salix. Large spots form on
leaves and the infection leads to premature leaf drop.
1044 J. Med. Plant. Res.
Pustules (sporodochia) with hyaline conidia appear,
allowing spread of the fungus to neighboring leaves and
plants (Gremmen, 1987).
Mayapple is poisonous to humans, but it is also thought
to produce toxins that prevent insect feeding. Faeth
(1978), however, identified three species of Lepidoptera
insects that were capable of detoxifying or metabolizing
these compounds. The larvae were able to mature to
adulthood when placed on live mayapple plants in the
laboratory.
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