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A method was established for content determination of two kinds of phenolic acids, including rosmarinic acid)(RA) and caffeic acid(CA), and six kinds of flavonoids including scutellarein-7-O-diglucuronide(SDG), luteolin-7-O-diglucuronide(LDG), apigenin-7-O-diglucuronide(ADG), scutellarin-7-O-glucuronide(SG), luteolin-7-O-glucuronide(LG), and apigenin-7-O-glucuronide(AG) in Perilla frutescens leaves. The content of eight chemical components was measured based on ten P. frutescens germplasms of different chemotypes of volatile oil, different cultivated years, and different harvesting periods. The results showed that there was a great difference between the two kinds of constituents of different germplasms. The total content of the two phenolic acids was 2.24-34.44 mg·g~(-1), and the total content of the six flavonoids was 11.55-34.71 mg·g~(-1). Then according to content from most to least, the order of each component was RA(2.13-33.97 mg·g~(-1)), LDG(1.31-14.80 mg·g~(-1)), SG(1.97-8.45 mg·g~(-1)), ADG(2.68-7.60 mg·g~(-1)), SDG(1.16-5.87 mg·g~(-1)), LG(0.78-1.91 mg·g~(-1)), AG(0.56-1.00 mg·g~(-1)), and CA(0.11-0.68 mg·g~(-1)). The chemical contents of the 5 PA-type germplasms in 2017 were mostly higher than those in 2018 showing a large variation with the cultivation years. These contents of two kinds of phenolic acids of 9 germplasms fluctuated with the harvesting time. The content decreased before early flower spike(the 3~(rd) to 18~(th) in August) at first and began to increase in flowering and fruiting period(the 18~(th) in August to 2~(nd) in September). However, these contents had slowly decreasing trend after 2~(nd) in September till 17~(th) in the same month. Interestingly, the content raised again in the maturity of fruits. The variation tendency of contents in six kinds of flavonoids components was inconsistent in different germplasms with the variation of harvesting time. The content of flavonoids in part of germplasms was negatively correlated with the fluctuation of phenolic acids. There was no correlation between phenolic acids and chemical type of the volatile oil. This paper may provide a reference for the high-quality germplasm of P. frutescens cultivation.

Two medicinal PA type Perilla germplasms were planted at five planting densities(D1,2 500 plants/Mu;D2,5 500 plants/Mu;D3,8 500 plants/Mu;D4,11 500 plants/Mu;D5,14 500 plants/Mu;1 Mu≈667 m~2). A total of 17 traits, including leaf shape, plant type, yield, volatile oil content and composition, were recorded and studied. With the planting density increased, the leaves appeared narrow, plants small, the deciduous leaves increased, and the leaf yield per plant was low, but the leaf yield per Mu increases significantly with the planting density, and was basically stable after reaching D4. The extraction rate of volatile oil from leaves at planting density D2-D5 was about 0.1% higher than that of D1, and there was no significant difference in the relative content of perillaldehyde, among 5 density. In order to achieve high leaf yield, it is recommended to plant at a density of D4, 11 500 plants/Mu(plant spacing is 15 cm, and row spacing is 40 cm); while comprehensive leaf yield and leaf morphology are recommended to be planted at a density of D2, 5 500 plants/Mu(plant spacing is 30 cm, and row spacing is 40 cm). At the same time, dense planting resistance of two germplasms were different. Number of secondary branches, first section with leaves and plant types were most important feature for the evaluation of the density tolerance of PA-type Perilla. This study provided a reference for the suitable density of PA-type Perilla, and laid a foundation for further study of the tolerance characteristics of different Perilla.

Fifty cultivated Perilla seeds were collected all over the country and planted in Beijing experiment field for morphology and chemical-type researches. Twenty morphological characteristics were selected and observed, and the essential oil from leaves was extracted by steam distillation and analyzed by GC-MS to confirm chemical-types. There were significant diversities in plant height, leaf color and morphology, and fruit color and weight. Clustering analysis was carried out based on these morphological characteristics. Six types were divided with their chemical-type designated. Type Ⅰ: Six germplasms, attributed to P. frutescens var. crispa, with dwarf plants, thin creased purple leaf, named Crispa, their chemical types were diversified, including EK, PAPK, PA and PK. Type Ⅱ: Six germplasms, attributed to P. frutescens var. crispa, plants were taller than type I and with thin and creased green leaf, named Big Crispa, all PK type. Type Ⅲ: Seventeen germplasms, attributed to P. frutescens var. frutescens with leaf color upside green and underside purple, tall plant and wide distribution all over the China, named Ordinary Frutescens, all PK. Type Ⅳ: Four germplasms, attributed to P. frutescens var. acuta with tall plant and small seed, named Acuta, all PK. Type Ⅴ: Seven germplasms, attributed to P. frutescens var. frutescens with green leaves, tall plants and long clusters, named Long-spike Frutescens, all PK. Type Ⅵ: Ten germplasms, attributed to P. frutescens var. frutescens with big, thick and creased leaf, named Thick-leaf Frutescens, including PK, PP, PL and PA. The morphological classification of this paper would lay the foundation for the taxonomic naming and following evaluation of the Perilla germplasm resources.This study also showed that there was no correspondence but a certain correlation between volatile oil chemical-types and subspecies classification and morphological characteristics of Perilla.

This experiment researched on three kinds of Perilla frutescens including the widespread PK, PA and rare PL chemotype. The Perilla samples were the mature leaves collected in nutrition, flowering and frutescence three different phenological periods, and at 7 am, 12 pm and 6 pm three day time. The volatile oil was extracted by steam distillationand analyzed by GC-MS, as a result, the three chemotype samples'volatile oil yield was between 0.08% and 0.96%; volatile oil yield of different growth period was as follow: nutrition>flowering>fructescence, and the volatile oil yield of nutrition period: PA type>PK type>PL type. Each chemotype was not affected by the growth and development, indicating that the chemotype is determined by genetic factors. Characteristic and main components of PA and PK type are relatively stable, and the characteristic components of PL type are significantly decreased with the growth. There are still a large number of upstream metabolism components, and the chemical type may have their primitiveness and changeability. The relative content of perillaldehyde, characteristic components of PA type, is basically decreased from morning to night, in all the period. The relative content of perillaketone, characteristic components of PK type, in nutrition and flowering period, when samples were collected at 12 noon is relatively higher than that at 7 am and 6 pm, and contrary to samples collected in frutescence period. The relative content of perillene, characteristic components of PL type, in nutrition and frutescence period are highest at 12 noon, while in flowering period is highest at 6 pm. According to the volatile oil yield and relative content of maincomponents, the best harvest time of PA type is in the morning of the nutrition period; the best harvest time of PK type is in the morning of all the period; and the best harvest time of PL type is at dusk of the nutrition period., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose., (Copyright© by the Chinese Pharmaceutical Association.)

This study, based on the findings for Perilla resources, aimed to describe the species, distribution, importance, features, utilization and status of quantitative Perilla resources in China. This not only helps people to know well about the existing resources and researching development, but also indicates the overall distribution, selection and rational use of Perilla resource in the future. According to the output types, Perilla resources are divided into two categories: wild resources and cultivated resources; and based on its common uses, the cultivated resources are further divided into medicine resources, seed-used resources and export resources. The distribution areas of wild resources include Henan, Sichuan, Anhui, Jiangxi, Guangxi, Hunan, Jiangsu and Zhejiang. The distribution areas of medicine resources are concentrated in Hebei, Anhui, Chongqing, Guangxi and Guangdong. Seed-used resources are mainly distributed in Gansu, Heilongjiang, Jilin, Chongqing and Yunnan. Export resource areas are mainly concentrated in coastal cities, such as Zhejiang, Jiangsu, Shandong and Zhejiang. For the further study, the essential oil of leaf samples from different areas were extracted by the steam distillation method and analyzed by GC-MS. The differences in essential oil chemotypes among different Perilla leaves were compared by analyzing their chemical constituents. The main 31 constituents of all samples included: perillaketone (0.93%-96.55%), perillaldehyde (0.10%-61.24%), perillene (52.15%), caryophyllene (3.22%-26.67%), and α-farnesene (2.10%-21.54%). These samples can be classified into following five chemotypes based on the synthesis pathways: PK-type, PA-type, PL-type, PP-type and EK-type. The chemotypes of wild resources included PK-type and PA-type, with PK-type as the majority. All of the five chemotypes are included in cultivated resources, with PA-type as the majority. Seed-used resources are all PK-type, and export resources are all PA-type. The P. frutescens var. frutescens include five chemotypes, with PK-type as the majority. The PK-type leaves of P. frutescens var. acuta are green, while the PA-type leaves are reddish purple. The P. fruteseens var. crispa was mainly PA type with reddish purple leaves. The differences of the main chemotypes provide a scientific basis for distinguishing between Zisu and Baisu in previous literatures. Based on the lung toxicity of PK and the traditional use of Perilla, the testing standard of essential oil and Perilla herb shall be built, and PA type is recommended to be used in traditional Chinese medicine., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose., (Copyright© by the Chinese Pharmaceutical Association.)

The volatile oil is the main component in the leaves of Perilla frutescens. According to the main types of monoterpenoids or aromatic compounds, it can be divided into different chemotypes and the main chemotypes of Chinese producing Perilla are PA type (mainly containing Perilla aldehyde and limonene), PK type (mainly containing perillaketone) and PP type (subdivided as PP-a type, with apiole as its main component; PP-m type, with myristicin as its main component; PP-e type, with elemicin as main component; PP-as type, with asarone as main component). Based on the biosynthetic pathways analysis, we also found that the formation of the particular chemotype is usually controlled by a single gene or a few genes, and different types have different pharmacological effects. In this paper, the classification under the species P. frutescens, main chemotypes of the volatile oil, and their biogenesis and regulation, pharmacological effect and influence factors are summarized and reviewed.