The scientific elucidation of daodi medicinal materials

Abstract

Abstract Daodi medicinal materials (DMMs), with unique characteristics and specific ecological growing environments, are recognized as high-quality medicinal products of Chinese medicinal materials (CMMs). The quality evaluation of CMMs is fundamental for standardization. The concept and application of DMMs have a long history as described in records in ancient books and rooted in practice and experience over generations. DMM is the specific term for pure, superior medicinal herbs with the following characteristics: optimum harvest season (reflecting the appropriate developmental stage of the plant), scrupulous processing, traditional preparation technology, etc. As DMM and high-quality medicinal products are traditionally thought to be closely related, modern scientific studies that confirm the association of these products are described. This article aims to clarify the scientific elucidation of DMMs.

Full text

Liuetal. Chin Med (2020) 15:86
https://doi.org/10.1186/s13020-020-00367-1
REVIEW
The scientic elucidation ofdaodi medicinal
materials
Xindan Liu1 , Ying Zhang1*, Menghua Wu1, Zhiguo Ma1, Zihan Huang1, Fang Tian1, Sihan Dong2, Simin Luo2,
Yu Zhou2, Jinju Zhang2, Nanxin Li2, Xiaofang He2 and Hui Cao1*
Abstract
Daodi medicinal materials (DMMs), with unique characteristics and specific ecological growing environments, are rec-
ognized as high-quality medicinal products of Chinese medicinal materials (CMMs). The quality evaluation of CMMs
is fundamental for standardization. The concept and application of DMMs have a long history as described in records
in ancient books and rooted in practice and experience over generations. DMM is the specific term for pure, superior
medicinal herbs with the following characteristics: optimum harvest season (reflecting the appropriate develop-
mental stage of the plant), scrupulous processing, traditional preparation technology, etc. As DMM and high-quality
medicinal products are traditionally thought to be closely related, modern scientific studies that confirm the associa-
tion of these products are described. This article aims to clarify the scientific elucidation of DMMs.
Keywords: Daodi medicinal materials, Chinese medicinal materials, Ecological environment, Chemical components,
Pharmacological functions
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Background
In recent years, as the use of Chinese medicinal materi-
als (CMMs) has increased, the international attention
paid to the safety, stability and efficacy of CMMs has
increased. Some authentic and superior CMMs that are
grown in specific regions and widely recognized as hav-
ing better therapeutic effects are called daodi medicinal
materials (DMMs) [1]. DMMs, based on the theory, ori-
gin, processing, and prominent curative effect of CMMs,
are the essence of Chinese cultural heritage [2]. DMMs
were first recorded in Zhen Zhu Nang Yao Xing Fu (Pre-
cious Drus in Rhyme), a book written 700years ago. e
term “daodi medicinal material” is widely found in Ben
Cao Pin Hui Jing Yao (Essentials of Materia Medica Dis-
tinctions), a book compiled by the Imperial Hospital dur-
ing the Ming Dynasty (1368–1644 A.D.), in which 268
medicinal herbals are listed. e entry “original source”
was formally listed under each medicinal herb heading,
specifying daodi production regions. It has been sug-
gested that the quality of CMMs is highly correlated with
their geographical origins. In ancient times, the identi-
fication of DMMs was commonly carried out based on
the characteristics of the superficies, and this approach
depended to a certain extent on empirical experiences
and assumptions. Currently, modern scientific analyti-
cal techniques may be applied to confirm the validity of
associations between high-quality medicinal products
and DMM to ensure their utility, clarifying the scientific
understanding of daodi medicinal materials.
e word “dao” (in “daodi”) is an ancient Chinese unit
of measurement used to divide administrative districts,
and this term can be retraced to the Eastern Han Dynasty
(25–220 A.D.) as described in Hou Han Shu (Book of
Later Han, 432–445 A.D.) [3]. In the Tang Dynasty (618–
907 A.D.), the nation was divided into 10 “dao” accord-
ing to landscapes in the Zhenguan Period, and then the
number was increased to 15 “dao” in the Kaiyuan Period.
Currently, “dao” is conceptually similar to the modern
organizational system of provinces. e word “di” (in
Open Access
Chinese Medicine
*Correspondence: zhangying@jnu.edu.cn; kovhuicao@aliyun.com
1 Research Center for Traditional Chinese Medicine of Lingnan (Southern
China), Jinan University, Guangzhou 510632, China
Full list of author information is available at the end of the article

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Liuetal. Chin Med (2020) 15:86
“daodi”) refers to regions and geography. Nowadays,
“daodi medicinal materials” refers to the distinctively
higher quality of the medicinal materials that grow in a
certain area.
e establishment of DMMs is related to resources,
agricultural technology and CMM development. In
ancient China, due to agriculture production, rich expe-
rience along with advanced technology in growing and
processing medicinal herbals was accumulated, which
resulted in the exchange of resources around the world
[4]. In addition, the vast territory of China, including
plains, hills, mountains, lakes, rivers and seas with differ-
ent climates, sunshine, soils and ecological environments,
provides favorable conditions for the growth of medici-
nal herbs. rough meticulous selection over the course
of production and continuous clinical tests, DMMs have
been proven to be definitely curative in medical treat-
ments and therefore have been handed down from gen-
eration to generation [5].
DMM can be very effective if proper consideration
is given to the characteristics of the original sources,
growth and seasonal changes of the material; however,
the same medicinal herb grown in different areas does
not have the same effectiveness even if they are the same
plant. In China, traditional Chinese medicine doctors
usually select a superior populations or variety to pre-
scribe based on geographical features. In addition, dif-
ferent harvest times or processing methods can greatly
influence the quality of CMMs in terms of chemical com-
ponents and pharmacological functions. us, DMM, as
an authentic and superior medicinal product, needs to be
validated by modern analytical methods for each CMM.
In this paper, the scientific elucidation of DMMs will be
introduced, as well as a putative production chain for
processing traditional, experience-based CMMs.
Daodi medicinal materials are theessence
ofChinese cultural heritage
Over the long course of clinical selection, by discarding
the inferior and retaining the superior, DMMs have been
acquired. DMMs represent the influence of populations,
together with optimum harvest season, habitat and grow-
ing conditions such as sunshine, soil, and water. Gener-
ally, the identification of DMMs is a useful tool for the
quality evaluation of CMMs.
Populations
Different growing environments may greatly influence
the quality and chemical components of closely related
populations. Modern experimental research, especially
molecular biological identification, has validated that the
different production areas of CMMs are closely related
to the quality and DNA sequence divergence of CMMs
[6–8]. For example, as the dominant constituents, patch-
oulol and pogostone are the basis for the anti-inflam-
matory activity of Pogostemon cablin (Blanco) Benth.
[9]. And it has been found that pogostone also exhibits
potent anti-fungal [9], antiapoptotic [10], antioxidant
[11], and immunosuppressive [12] properties. In our
previous study, P. cablin produced in Shipai (in Guang-
zhou city, Guangdong province, SP) and Gaoyao (in
Zhaoqing city, Guangdong province, GY) differed from
P. cablin cultivated in Hainan province (HN) and Zhan-
jiang city (in Guangdong province, ZJ) not only in the
total amount of volatile oil but also in genotype [13–15].
According to the composition of the volatile oil, P. cab-
lin is divided into two chemotypes: SP and GY cultivars
belong to the pogostone-type, while the HN and ZJ cul-
tivars belong to the patchoulol-type (Fig. 1). Moreover,
we have demonstrated that the sequence divergence of
both the matK and 18S rRNA genes among 6 samples
of P. cablin from different locations was well correlated
with the regions of cultivation and intraspecific essential
oil chemotypes (Fig.2) [16]. e same is true for other
medicinal herbs. e major pharmacological compo-
nents in Cnidium monnieri (L.) Cuss. are coumarins
Fig. 1 Structures of the pogostone and patchoulol in Pogostemon cablin

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Liuetal. Chin Med (2020) 15:86
Fig. 2 Volatile oil composition in the leaves (a), comparison of the variable sites in the matK sequence (b), comparison of the variable sites in the
18S rRNA sequence (c) and cluster trees of both the matK and 18S rRNA gene sequences (d) of Pogostemon cablin (Blanco) Benth. from 6 different
locations. The top number indicates the nucleotide position upstream of the matK (b) and the 18S rRNA (c) sequence, an asterisk (*) indicates the
same nucleotide as the P1 sequence, and a hyphen (—) indicates an alignment gap (c)

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Liuetal. Chin Med (2020) 15:86
[17]. Similarly, according to the coumarin chemotypes,
C. monnieri has been classified into three chemotypes,
the osthol-linear furanocoumarins-type (chemotype I),
principally cultivated in regions of Jiangsu and Hunan
provinces; the angular furanocoumarins-type (chemo-
type II), mainly produced in Heilongjiang province; and
the transition-type (chemotype III), largely came from
Henan and Hebei regions [18]. It was found that there
were 12 variable sites in the matK gene sequence of C.
monnieri from different populations. A phylogenetic tree
constructed by the neighbor-joining (NJ) method showed
that the phylogenetic relationship of 6 C. monnieri cul-
tivars was well correlated with their geographical distri-
bution and intraspecific coumarin chemotypes of (Fig.3)
[19]. Likewise, Laboratory research showed a clear cor-
relation between the rDNA ITS sequence and the phe-
notype of Dendrobium officinale Kimura et Migo from
different populations [20]. e phylogenetic relationship
predicted by the 5S rRNA spacer region data correlated
well with the essential oil chemotype of Acorus calamus
L. collected from various locations [21]. However, the dif-
ference in the alkaloid content of Fritillaria thunbergii
Miq. from various habitats did not result from variation
in the 5S rRNA sequence but from the microenviron-
ment [22]. It’s reported that 5S rRNA is highly-conserved
arcoss all species [23], thus, different environments did
not produce changes in 5S rRNA of different F. thun-
bergii populations, but produced differences in second-
ary metabolites. In these cases, it can be concluded that
genetic diversity existed among different populations is
relevant to the cultivation regions except some highly-
conserved DNA markers.
Harvest time
CMMs harvested during different growing periods
contain different plant metabolites. For instance, the
content of essential oil increased as the age of P. cablin
increased: patchoulol, α-bulnesene and other sesquiter-
penes accumulated to high concentrations at 210 days
after maturation [24]. According to the report from Jin
et al. [25], Chaenomeles speciosa (Sweet) Nakai pro-
duced the highest quality yields when harvested in early
July. In the case of Desmodium styracifolium (Osb.)
Merr., the best collection season was early October,
when the highest concentrations of polysaccharides,
flavonoids and schaftoside were measured [26].
Sunshine
Sunshine is an important factor for the formation of
DMMs. For example, the content of volatile compo-
nents in Houttuynia cordata unb. was closely related
to light intensity: monoterpenoids and nonterpenoids
were positively and negatively associated with light
intensity, respectively [27]. In Viola yedoensis Makino,
the content of flavonoids and coumarins was positively
correlated with light intensity [28]. Although it has
been demonstrated that higher concentrations of total
patchoulol corresponded to lower light intensity in P.
cablin, there was no statistically significant correlation
between patchoulol content and shade [29]. In recent
years, circadian clocks that temporally organize many
aspects of growth and metabolism have even been
found in numerous plant species [30–32]. For example,
in Antirrhinum majus L., monoterpene synthase mRNA
levels and corresponding monoterpene emission, which
followed diurnal rhythms, were controlled by a circa-
dian clock [33]. A similar daily fluctuation was found
in the endogenous level of geranyl acetate and in the
expression of its biosynthetic gene, alcohol acetyl trans-
ferase in Rosa rugosa unb. [31].
Soil
Soil is also important for the identification of DMMs
and for the evaluation of quality. Modern pharmacologic
studies have proven that the specific composition of soil
has a large influence on the quality and quantity of the
chemicals in medicinal herbs. For example, soil available
iron (Fe) could promote the accumulation of flavonoids,
while soil available manganese (Mn), total potassium
(K), and available K had an inhibitory effect on flavonoid
content in Spatholobus suberectus Dunn [34]. In Citrus
grandis ‘Tomentosa’, the content of soil available copper
(Cu), zinc (Zn), Mn, boron (B), and molybdenum (Mo)
was positively associated with flavonoid concentrations
and naringin concentrations [35]. ere was a positive
correlation between soil total nitrogen (N), available K
and emodin in Polygonum cuspidatum Sieb. et Zucc. [36].
Soil Mn was a favorable factor for accumulating schisan-
therin A in Schisandra sphenanthera Rehd. et Wils., as a
significant correlation was also found between these fac-
tors [37].
Fig. 3 Phylogenetic tree of the matK gene sequence (E) of Cnidium
monnieri (L.) Cuss. from six locations (C1–C6)

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Liuetal. Chin Med (2020) 15:86
Water
Another matter regarding DMMs that warrants atten-
tion is water. As shown in Aconitum carmichaelii Debx.,
the heavy metals cadmium (Cd), arsenic (As), mercury
(Hg), and lead (Pb) concentrations in it were positively
associated with the water in Fujiang River (p < 0.05) [38].
is result indicates that the quality of CMMs can also
be affected by water. To meet the growing demand of
DMMs, additional detailed studies should be undertaken
in this field.
Comprehensive ecological factors
Comprehensive research on the relationship between
different ecological environment factors and the qual-
ity of CMMs has also been recorded. For example, in
Scutellaria baicalensis Georgi, most of the chemical
constituents were negatively correlated with latitude
and positively correlated with temperature. Generally,
the contents of 21 chemical constituents were higher at
low latitudes than at high latitudes. By gradual regres-
sion analysis, it was found that the content of baicalin
in S. baicalensis was negatively correlated with latitude.
Similarly, the content of inorganic elements in soil was
excessively high (magnesium (Mg) and calcium (Ca)
excluded), which had a negative effect on the accumula-
tion of chemical constituents in S. baicalensis [39, 40].
Taking the well-known antioxidant herb Panax ginseng
C. A. Mey. as another example, low temperature was a
favorable factor for the accumulation of ginsenosides, as
a negative correlation was found between temperature
and ginsenoside contents within a certain temperature
range, while the levels of soil available B, effective Fe and
available N were positively correlated to ginsenoside con-
tents [41]. In recent years, due to overexploitation, the
destruction of the ecological environment and the lack
of proper cultivation practices, the geographical distri-
butions of most DMMs may undergo large changes. For
example, although the Changzhi region of Shanxi prov-
ince and provinces of north-east China was P. ginseng’s
original production center, the present production center
of it is in Xiaoxinganling region (in Heilongjiang prov-
ince) and Changbaishan region (in Jilin province) [42].
Similarly, Panax notoginseng (Burk.) F. H. Chen histori-
cally came from the Tianzhou region (in Guangxi prov-
ince), but now the dominant medicinal material comes
from Wenshan region (in Yunnan province) [43]. In these
cases, predicting the geographical distribution of CMMs
is important for resource conservation and regional man-
agement. erefore, a geographic information system
based on a computer program (TCMGIS) was developed
to predict the distribution of CMMs. By integrating geo-
graphic location, climate and soil type databases, TCM-
GIS was able to determine the impacts of environmental
components and predict the large-scale distribution of
target medicinal herbs such as P. cablin [44], Artemi-
sia annua L. [45], Polygonum multiflorum unb. [46],
Morinda officinalis How [47], Aquilaria sinensis (Lour.)
Gilg [48], Rheum tanguticum Maxim. ex Balf. [49], Amo-
mum villosum Lour. [50], etc.
Traditional descriptions ofdaodi medicinal
materials byfamous physicians inancient China
In the use of CMMs, a large emphasis has been placed
on the identification of DMMs since ancient times. As
recorded in Shen Nong Ben Cao Jing (e Divine Shen-
nong’s Classic of Materia Medica, 25–220 A.D.) [51],
“each medicinal material has laws for its production
region, authenticity, and freshness.” In various chapters
of that book, locations in ancient kingdoms and regions,
such as mountain valley, river valley or marshes, were
mentioned for the first time as medicinal herbs sources.
is record indicates that different CMMs come from
certain specific areas. In his immense book Ben Cao Jing
Ji Zhu (Collection of Commentaries on the Classic of
the Materia Medica, 480–498 A.D.) [52], Tao Hongjing,
a well-known physician in the Northern and Southern
Dynasties (420–589 A.D.), used such terms “good”, “quite
good”, “fairly good”, “excellent” and “best” to describe
the effects of over 40 medicinal herbals commonly used
in medical treatment. Moreover, correlations between
the sources, developmental stages and efficacy of these
medicinal herbs were described. Sun Simiao, a famous
physician and pharmacologist of the Tang Dynasty
(618–907 A.D.), stated the following in his book Qian
Jin Yi Fang (Formulas Worth a ousand Gold Pieces,
682 A.D.) [53]: “Medicinal herbs used by ancient phy-
sicians were always from designated original sources,
which accounted for their great effectiveness in medi-
cal treatment”. In that book, he comprehensively sorted
519 DMMs and systematically stipulated 133 regions of
production. According to Kou Zongshi, a famous physi-
cian of the Song Dynasty (960–1279 A.D.), in his book
Ben Cao Yan Yi (Extension of the Materia Medica, 1116
A.D.), “in prescribing medicinal herbs, care should always
be taken to select those from proper sources to ensure
their effectiveness”, greatly emphasizing the designated
original sources of medicinal herbs [54]. During the Jin
and Yuan Dynasties (1115–1368 A.D.), the text Yong Yao
Fa Xiang (Medication Method, 1249 A.D.) also suggested
that one could achieve excellent treatment results only by
using DMMs with proper production regions and harvest
time. en, the Ming Dynasty (1368-1644 A.D.) docu-
ment Ben Cao Meng Quan (Materia Medica Companion,
1565 A.D.) stated that “the effect will be definitely dif-
ferent if medicinal materials are produced in a different
environment” [55]. e record in Yi Xue Yuan Liu Shi

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Liuetal. Chin Med (2020) 15:86
(Origins of Medicine, 1767 A.D.) attached similar impor-
tance to the use of DMMs collected from certain original
sources [56]. All of this historical literature showed that
the use of DMMs has been a practice since ancient times.
The scientic elucidation ofdaodi medicinal
materials
DMMs are the subset of CMMs that meet the high-
est quality criteria. DMMs are not only associated with
specific geographic regions (Fig.4) but also linked to the
chemical components and pharmacological function of
CMMs.
Chemical components
As we described above, ecological environments such as
topography, sunshine, soil, and water directly influence
the secondary metabolites (many of which are bioactive
components) in medicinal herbs. e many names of
DMMs reflect the connotations of production regions;
for instance, “qin pi” (Fraxinus chinensis Roxb.), “fen qi”
(Astragalus membranaceus (Fisch.) Bge.), “huai di huang”
(Rehmannia glutinosa Libosch.) and “ba dou” (Croton tig-
lium L.), where “qin”, “ fen”, “ huai”, and “ba” refer to the
names of regions used over the course of ancient West-
ern Zhou Dynasty (1046–771 B.C.) [1]. Modern experi-
mental research has validated that DMMs growing in
a certain production region are often of high quality
(Table 1). For example, the ancient Chinese medicine
book Xin Xiu Ben Cao (Newly Revised Materia Medica,
659 A.D.) [57] said that “Fraxinus chinensis Roxb., which
can change the color of water to a fluorescent color after
soaking, is thought to be superior in quality” (Fig. 5).
Currently, scientific evidence supporting the rational for
such description is available. F. chinensis produced from
Shaanxi province has a higher content of aesculin and
aesculetin than that produced in Sichuan province and
Liaoning province, and its stronger fluorescence reac-
tion is consistent with the description written in ancient
times [58, 59]. e same observation is true for Astra-
galus membranaceus (Fisch.) Bge. is herb is principally
cultivated in a region in Shanxi province, and the cultivar
produced in this region contains more astragaloside than
do cultivars produced in Shandong, Inner Mongolia,
Hebei and Jilin provinces [60]. It is generally recognized
that Rehmannia glutinosa Libosch. cultivated in Henan
province is of particularly high quality. Modern experi-
mental studies have demonstrated that higher levels of
the active constituent catalpol content are present in R.
glutinosa grown in this region than in cultivars grown
in areas of Xianyang (in Shaanxi province) and Dali (in
Shaanxi province) [61]. Similarly, A. villosum cultivated
in Yangchun (in Guangdong province) is believed to be
Fig. 4 The distribution of some daodi medicinal materials in China

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Liuetal. Chin Med (2020) 15:86
Table 1 The contents (%) of active constituents in dierent Chinese medicinal materials in daodi production region
andnon-daodi production regions
CMM Chinese medicinal material
No. CMM Active
constituents Content (%) References
Daodi
production
region
Non-daodi production region
1Fraxinus chinensis
Roxb. Aesculin, aescu-
letin Shaanxi: aesculin
(4.37%), aescu-
letin (1.92%)
Sichuan: aesculin (1.10%), aesculetin
(0.21%) Liaoning: aesculin (2.21%), aescu-
letin (0.19%) [58, 59]
2Astragalus
membranaceus
(Fisch.) Bge.
Astragaloside Shanxi: 0.37% Shandong: 0.12% Inner Mongolia:
0.11% Hebei: 0.29% Jilin: 0.32% [60]
3Rehmannia gluti-
nosa Libosch. Catalpol Henan: 0.76% Xianyang, Shaanxi: 0.34% Dali, Shaanxi: 0.33% [61]
4Amomum vil-
losum Lour. Bornyl acetate Yangchun,
Guangdong:
65.82%
Gaozhou, Guang-
dong: 55.95% Guangxi: 61.75% Yunnan: 50.92% Burma: 60.71% [62–64]
5Pogostemon
cablin (Blanco)
Benth.
Pogostone Shipai, Guang-
zhou, Guang-
dong: 68.43%
Gaoyao, Zhao-
qing, Guang-
dong: 26.15%
Leizhou, Zhanji-
ang, Guang-
dong: 4.78%
Wuchuan,
Zhanjiang,
Guangdong:
5.20%
Hainan: 8.97% [65–70]
Fig. 5 The herbal classic Xin Xiu Ben Cao (Newly Revised Materia Medica) describes the metachromatism-based quality evaluation of “qin pi”
(Fraxinus chinensis Roxb.)

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Liuetal. Chin Med (2020) 15:86
superior in quality. e effective medicinal elements in A.
villosum is bornyl acetate. Modern experimental research
has validated that Yangchun-cultivated A. villosum has
the highest effective component content among different
populations [62–64]. In other example, P. cablin culti-
vated in Shipai (in Guangzhou city, Guangdong province)
is of particularly high quality. It produced higher levels of
the active constituent pogostone than that cultivated in
Gaoyao (in Zhaoqing city, Guangdong province), Leizhou
(in Zhanjiang city, Guangdong province), Wuchuan (in
Zhanjiang city, Guangdong province) and Hainan prov-
ince [65–70]. Interestingly, the same is true for toxicol-
ogy. A. carmichaelii produced from plantation sites at
Jiangyou county of Sichuan province is believed to be
superior in quality. e proportions of the major bioac-
tive constituents monoester alkaloids to toxic constitu-
ents diester alkaloids amount among 5 samples of A.
carmichaelii from different localities were well correla-
tive with their regions of cultivation. e highest propor-
tion occurred in cultivar Jiangyou (in Sichuan province),
followed by cultivars Hanzhong (in Shaaxi province),
Butuo (in Sichuan province), Weishan (in Yunnan prov-
ince), and Anxian (in Sichuan province) [71].
Pharmacological functions
Pharmacological functions are actually the outside mani-
festations of CMMs. In the case of DMMs, the conditions
in a certain region are thought to confer clinical supe-
riority, and for this reason, DMMs are considered the
most efficacious among CMMs [72]. Scientific evidence
supporting the alleged clinical superiority of DMMs is
the subject of ongoing research. For example, Dendro-
bium huoshanense C. Z. Tang et S. J. Cheng produced in
Huoshan (in Anhui province) is considered to be superior
in quality. Accordingly, the hepatoprotective effect is the
best for the Huoshan cultivar, second for the Yunnan cul-
tivar, and last for the other region cultivars [73]. P. cablin
has been classified into two chemotypes, the patchoulol-
type, including cultivars HN and ZJ, and the pogostone-
type, including cultivars SP and GY. Accordingly, this
cultivars produced in GY are more potent than those
from ZJ in terms of promoting digestion [74] and anti-
bacterial [75] effects. In addition, the toxicity of DMMs
is often less potent than that of non-DMMs. For instance,
P. multiflorum is principally cultivated in region Deqing
county of Guangdong province, which has the largest
output and the longest history of medicinal use. Accord-
ingly, cultivar Deqing showed less potent cytotoxicity
than cultivar Chongqing in HepG2 and LO2 cells [76].
ese studies show considerable promise for explaining
the scientific mechanism of DMM superiority.
Daodi medicinal materials are thebasis
ofthemedicinal industry andclinical practice
CMMs are the materials processed into decoction ingre-
dients or used to produce proprietary drugs. e iden-
tification of DMMs is important in quality evaluation
and disease treatment. In addition to the optimum har-
vest season, the processing and standard prescription
of CMMs produce the unique characteristics of DMMs,
and a plausible production chain of CMMs is hypothe-
sized in Fig.6. e production chain of CMMs is based
on the content we described above, including popula-
tions, designated growing regions (daodi), and harvest
season, as well as the extensive quality control knowledge
accumulated for CMMs by Liu etal. [77–80]. Compared
to previous production chain of CMMs [77–80], factors
such as populations, designated growing regions and
Fig. 6 A putative production chain for CMMs

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Liuetal. Chin Med (2020) 15:86
harvest time directly influenced the quality of CMMs
were emphasized. Every procedure in the production
chain should be standardized to guarantee the prominent
curative effect of medicinal materials. For example, the
manufacturing procedure for Pinellia ternata (unb.)
Breit. was standardized by orthogonal design [81]. In
addition, modern analytical methods have revealed the
processing mechanism of many CMMs, including Cop-
tis chinensis Franch. [82–84], Xanthium sibiricum Patr.
[85–87], Siegesbeckia orientalis L. [88, 89], Descurainia
sophia (L.) Webb. ex Prantl. [90, 91], Cassia obtusifolia L.
[92, 93], etc. Additionally, cooperation among universi-
ties, research institutes and pharmaceutical manufactur-
ers should be strengthened to communicate information
regarding CMMs.
Conclusions
DMMs have long maintained, currently have, and will
continue to maintain a good reputation on the basis of
their excellent curative effects. In our review, DMM is
the specific term for pure, superior medicinal herbs with
the following characteristics: optimum harvest season
(reflecting the appropriate developmental stage of the
plant), scrupulous processing, traditional preparation
technology, etc. Historical literature, modern phyto-
chemical and pharmacological methods have provided
additional scientific data and a theoretical basis to vali-
date the mechanisms of DMMs. In addition, every pro-
cedure in the production chain of CMMs should be
standardized to guarantee the prominent curative effect
of medicinal materials. Effectively establishing a correla-
tion among the active components, clinical efficacy and
identity of DMMs is an important aspect in the quality
evaluation of CMMs. e core scientific elucidation of
DMMs should be continuously carried out, and multidis-
ciplinary measures should be adopted to explore scien-
tific and practical methodologies for the further research
of DMMs.
Abbreviations
DMMs: daodi medicinal materials; CMMs: Chinese medicinal materials; SP:
Shipai (in Guangzhou City, Guangdong province); GY: Gaoyao (in Zhaoqing
City, Guangdong province); HN: Hainan province; ZJ: Zhanjiang City (in Guang-
dong province); NJ: neighbor-joining; Fe: iron; Mn: manganese; K: potassium;
Cu: copper; Zn: zinc; B: boron; Mo: molybdenum; N: nitrogen; Cd: cadmium;
As: arsenic; Hg: mercury; Pb: lead; Mg: magnesium; Ca: calcium; TCMGIS: geo-
graphic information system based on a computer program.
Acknowledgements
Not applicable.
Authors’ contributions
HC and XL conceived, designed and wrote the review; YZ, MW and ZM
collected the data; YZ, ZH, FT, SD, SL, YZ, JZ, NL and XH revised the paper. All
authors read and approved the final manuscript.
Funding
This work was supported by the 6th National Academic Experience Inherit-
ance Program of Famous Chinese Medicine Experts (Prof. Hui Cao) (No.
176-2017-XMZC-0166-01).
Availability of data and materials
Not applicable.
Ethics approval and consent to participate
Not applicable.
Consent for publication
Not applicable.
Competing interests
The authors declare that they have no competing interests.
Author details
1 Research Center for Traditional Chinese Medicine of Lingnan (Southern
China), Jinan University, Guangzhou 510632, China. 2 College of Pharmacy,
Jinan University, Guangzhou 510632, China.
Received: 12 May 2020 Accepted: 13 August 2020
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