Research progress on chemical constituents and pharmacological activities of Amomum longiligulare T.L.Wu

QU Hui-juan, OU Hong-ya, LIN Kai-wen, WEI Na

College of Pharmacy, Hainan Medical University, Haikou 570000, China

Keywords:

ABSTRACT In order to develop and utilize the tropical medicinal resource Amomum (A.) longiligulare T.L.Wu more reasonably and effectively, this paper summarizes the research progress in chemical constituents and pharmacological activities of A.longiligulare by consulting the literatures, so as to provide a certain theoretical basis for exploring its material basis.The chemical constituents of A.longiligulare mainly include volatile oil, diphenylheptane and flavonoids,which have good efficacy in anti-peptic ulcer, as well as antioxidant, analgesic and other pharmacological activities.This paper briefly discusses the reasons for the differences in the composition of volatile oil studied by different scholars.By summarizing its pharmacological activities, it is found that its various pharmacological activities may be the basis of its anti-peptic ulcer.

1.Introduction

Amomi fructus is one of the four famous southern medicines in China, which belongs to the genus Cardamom of Zingiberaceae.In Chinese Pharmacopoeia, there are three sources of authentic Amomi fructus, namely Amomum villosum Lour., Amomum longiligulare T.L.Wu or Amomum villosum Lour.var.xanthioides T.L.Wu et Senjen[1].Amomum longiligulare (A.longiligulare), which is mainly produced in Hainan, is a perennial herb, but because of its special reproductive structure, that is, its inflorescence is extracted from the rhizome and the pistil stigma is higher than the stamens[2], it is difficult to pollinate naturally and the seed setting rate is low.The under-forest economic planting model of A.longiligulare and other medicinal materials in Hainan has a unique development advantage in Hainan.In recent years, this model has been developing continuously, which can bring benefits to the economy of Hainan[3].In addition, the study on the composition and activity of A.longiligulare in Hainan is conducive to the discovery and optimization of its planting conditions, and the excellent planting conditions are also conducive to the improvement of its medicinal value and the development of TCM industry.

A.longiligulare has the pungent and warm properties of Zingiberaceae plants, which can regulate qi, warm stomach, dissolve spleen dampness, effectively treat spleen and stomach deficiency cold, abdominal distension, and is usually used as the raw material of spicy spices.A.longiligulare has a long history of medicinal use,and many compound proprietary Chinese medicines are compatible with A.longiligulare, such as Xiangsha Yangwei pills, Xiangsha Pingwei Powder, Xiangsha Liujun pills, Xiangsha Zhizhu pills and so on.

With the development of instrumental analysis, a variety of chemical constituents in A.longiligulare have been isolated and identified, such as volatile oils, diarylheptane, flavonoids, sterols,organic acids, glycosides and so on.Modern pharmacological studies have also shown that A.longiligulare has a variety of pharmacological activities[4], such as improving gastrointestinal function, anti-ulcer, anti-diarrhea, anti-inflammation, antibacterial,analgesia, antioxidation and so on.Chemical components are closely related to pharmacological activity.based on the holistic concept of traditional Chinese medicine (TCM), there may be some interactions between the total chemical components of TCM and affect the pharmacological activity of TCM.At present, the research content of A.longiligulare is less than that in Amomum villosum.Because Hainan Province has advantaged planting conditions, it is necessary to summarize the chemical composition and pharmacological action of A.longiligulare in recent years.in order to provide a theoretical basis for the material basic research and new drug creation of A.longiligulare in Hainan, and to provide a theoretical basis for the development and utilization of tropical medicinal resources.

2.Chemical constituents of Amomum longiligulare

The chemical components of A.longiligulare mainly include volatile components and non-volatile components, volatile components are mainly volatile oils, and non-volatile components include diarylheptane, flavonoids, phenolic acids, organic acids,glycosides and so on.

2.1 Volatile components

The volatile oil components of Amomi fructus mainly produced in Guangdong Province were studied earlier.The earliest literature report on the volatile oil components of A.longiligulare was reported by Wu Zhong et al.[5] Supercritical carbon dioxide fluid extraction method was used to study the effective components of A.longiligulare, and GC-MS- computer coupled technology was used to analyze it.Results 23 components were isolated and identified in kettle I and 69 in kettle II.Both kettle I and kettle II mainly contained L-bornyl acetate, camphor and borneol, of which L-bornyl acetate was the highest, followed by camphor and borneol.Camphene, limonene, myrcene and α-pinene were also detected in kettle II.Qin Quan et al.[6] used steam distillation to determine the content of bornyl acetate in Hainan sand.The results showed that the content of bornyl acetate in A.longiligulare was 0.6% (mL/g), which did not meet the standard of Chinese Pharmacopoeia (0.9%).

Huang Yan et al[7] also used supercritical CO2fluid extraction method to extract volatile oil from A.longiligulare, and its components were determined by GC-MS, but the main components such as bornyl acetate, camphor and borneol were not detected in this experiment, but flavonols, alcohols and esters were mainly detected, which is quite different from the research results of Wu Zhong et al.[5].In view of the fact that the specific conditions of the supercritical fluid extraction method are not given in the literature published by Wu Zhong et al, it is preliminarily speculated that the reason for the great difference in the detection results may be related to the extraction conditions.Dong Lin[8] studied the fatsoluble chemical constituents of the petroleum ether extract of A.longiligulare, and identified linalool, nerol, cubane and other components.The fat-soluble parts mainly contain phenolic acids,enols, esters and long-chain fatty acids, and the common components such as bornyl acetate, camphor and borneol in the volatile oil of A.longiligulare were not detected.The extraction method used in this experiment is different from that mentioned above, so the reason why bornyl acetate and other main components are not detected may be related to the great difference in the extraction method.

The heating time of medicinal materials containing volatile components should not be long, so the special decocting method of aromatic dampness TCM is "Hou Xia".In view of the instability of the structural properties of volatile components such as bornyl acetate, Pan Hongling et al[9] studied the content stability of bornyl acetate in Amomum villosum with different crushing methods and different storage time.The results showed that the content measured by high-speed grinder was 0.91%, and that of FZ102 universal grinder and frozen mixed ball mill was 1.42%.The high-speed grinder produces more heat when crushing the medicinal materials,so it has a great influence on the volatile components; the longer the storage time of A.longiligulare powder, the lower the content of bornyl acetate.Considering that the crushing equipment used by Huang Yan[7] and Dong Lin[8] are SF-180 high-speed universal grinders, the main volatile components such as bornyl acetate in A.longiligulare may be lost in the process of crushing, and although Dong Lin et al used ethanol cold extraction, bornyl acetate is soluble in ethanol, but in the subsequent process of repeated extraction with petroleum ether, due to the strong volatility of petroleum ether.It is speculated that bornyl acetate and other components in Amomi fructus may be removed with petroleum ether in the process of repeated extraction.

In order to study the chemical composition of A.longiligulare and obtain the volatile components with high content, some scholars studied the extraction technology of Amomi fructus.Steam distillation is a simple and inexpensive method for the extraction of volatile oil.it is necessary to control the particle size and extraction time of medicinal materials.The powder is easy to absorb volatile oil when the particle is too small, and it is easy to lose volatile oil after too long heating time[10].

In summary, in the follow-up study of volatile components of Amomi fructus, attention should be paid to the possible loss of volatile components caused by storage environment, pretreatment steps and extraction methods.

Some scholars have also studied the volatile chemical constituents of different parts of A.longiligulare.For example, Nanyu et al.[11]studied the chemical constituents of A.longiligulare leaf oil by supercritical carbon dioxide fluid extraction for the first time, and obtained volatile components such as α-pinene, β-pinene, linalool,caryophyllene and metenolone.Some scholars have studied the same kind of A.longiligulare from Vietnam[12].The volatile oil from the root, stem and leaf of A.longiligulare was extracted by steam distillation, and its chemical composition was studied by GC-MS method.The results showed that the volatile oil in the leaves mainly contained β-caryophyllene, β-pinene, epoxide and α-hemp, etc.,and the main components in the stem were β-caryophyllene and α-naphthene.Camphene and bornyl acetate were mainly found in its roots, and bornyl acetate was detected in roots, stems and leaves,but camphor and borneol were not detected in all three.The fruits of A.longiligulare were not studied in the above studies.

2.2 Diarylheptane and flavonoids

Most Zingiberaceae plants often contain diarylheptane and flavonoids, which are also found in the chemical constituents of A.longiligulare, but there are few studies on these components in A.longiligulare.

Liu Jinpeng[13] was dissolved in water after alcohol extraction, then extracted by petroleum ether, dichloromethane and ethyl acetate respectively, and subdivided by different types of chromatographic columns to study the chemical constituents of A.longiligulare.Results diphenylheptane and flavonoids were isolated and identified in dichloromethane.

3.Study on pharmacological activity

3.1 Anti-peptic ulcer

Peptic ulcer is often manifested as acid regurgitation and epigastric pain, and there are many causes of peptic ulcer.TCM believes that poor diet, poor emotion, external pathogen invading stomach and weakness of spleen and stomach can cause stomach qi block,obstruction and pain[14].Western medicine studies believe that it isrelated to Helicobacter pylori infection[15] and excessive secretion of gastric acid and pepsin.In a word, its pathogenesis is usually considered to be the imbalance of gastric mucosal attack factor and defense factor.The macro dialectics of TCM and the micro concept of western medicine complement each other, that is, the main body of TCM to support the positive and dispel evil, turn saprophytic muscle, western medicine mainly restrain the attack factor, enhance the defense factor.

Tab 1 Study on the antiulcer effect of Amomum longiligulare T.L.Wu

As a TCM, Amomi fructus has a long history, which can dissolve dampness and appetizer and treat deficiency and cold of spleen and stomach.Xiangsha Yangwei Pill, a classical prescription of TCM,takes it as the king′s medicine.Based on this exact empirical effect,the modern pharmacological activity of A.longiligulare is focused on the treatment of peptic ulcer.At present, it has been reported that the treatment of peptic ulcer by A.longiligulare is mainly anti-gastric ulcer and anti-ulcerative colitis.

3.1.1 Anti-gastric ulcer

Compared with A.villosum, there are few studies on the anti-peptic ulcer of A.longiligulare, and only 2 literatures on anti-gastric ulcer have been found.The specific research contents are as follows:

3.1.2 Anti-ulcerative colitis

Zhu Yi et al.[18] established the model of ulcerative colitis in SD rats induced by 2-dinitrochlorobenzene and acetic acid, and treated with emulsion made from volatile oil of A.longiligulare.The results showed that the clinical symptoms of rats were alleviated and the pathological tissue condition was improved, but the mechanism of action was not studied.Zhao Jin et al.[19] in addition to the abovementioned modeling method, another modeling method was added,even though Balb/c mice were induced by sodium dextran sulfate to establish experimental ulcerative colitis, the same administration method was used, and the mechanism of A.longiligulare volatile oil in the treatment of ulcerative colitis was studied.In view of the fact that the occurrence of ulcers may be related to the production of a large number of free radicals in the body, this experiment examined the factors related to the oxidation-antioxidant system, such as nitric oxide free radicals and nitric oxide synthase, which are closely related to the production of free radicals by gastrointestinal mucosal cells, as well as antioxidant enzymes involved in scavenging free radicals.Intercellular adhesion factor (ICAM), inflammatory cytokine TNF-α and targeting factor NF-κBp65, which are closely related to inflammatory response and immune response, were investigated.The possible mechanism is to reduce the production of free radicals, reduce the adhesion between colon cells, and significantly inhibit the expression of TNF-α and NF-κBp65 to play an anti-inflammatory effect.

3.2 Antioxidant activity

Liu Jinpeng[13] antioxidation test of diphenylheptane compounds isolated from dichloromethane extract of A.longiligulare was carried out by DPPH method, and positive results were obtained.Dong Lin[20] et al used DPPH method and hydroxyl radical scavenging ability test.The results showed that dichloromethane and ethyl acetate parts of A.longiligulare showed better antioxidant activity,but the two parts were not further separated.Combined with the monomer compounds isolated from A.longiligulare dichloromethane by Liu Jinpeng[13], it is suggested that dichloromethane may contain more diphenylheptane compounds.And diphenylheptane compounds have good antioxidant activity.It was mentioned in 2.1.2 that oxygen free radicals may be involved in the occurrence of gastrointestinal mucosal ulcers, and the antioxidant test of A.longiligulare proved the good antioxidant activity of diphenylheptane compounds.therefore,it is speculated that diphenylheptane compounds may be one of the material bases for the treatment of gastrointestinal ulcers.

3.3 Other activities

A.longiligulare not only has the above-mentioned activities,but also has anti-inflammatory, analgesic and antidiarrheal activities.According to the study of Zhao Jin[21], the volatile oil of A.longiligulare has good anti-inflammatory activity on mouse inflammatory model made of xylene and carrageenan, and good analgesic activity on hot plate method and acetic acid-induced pain model.it has antidiarrheal effect on diarrhea model made by Senna leaves.A.longiligulare has good anti-inflammatory, analgesic and antidiarrheal activities, which may play an important role in the mechanism of anti-peptic ulcer.

4.Conclusion

The overall conditioning effect of TCM on the body may be based on the characteristics of multi-chemical components and multiaction targets of TCM, and the chemical components may play a coordinated role among them, thus having an important impact on the comprehensive pharmacological activity.The complexity of the therapeutic mechanism of TCM is also related to its various chemical compositions.at present, TCM chemistry, pharmacology and other related disciplines are committed to exploring the material basis of TCM.

A.longiligulare is an authentic medicinal material in Hainan Province, and it has been proved that the chemical composition of A.longiligulare is closer to that of A.villosum compared with A.villosum Lour.var.xanthioides T.L.Wu et Senjen.However, up to now, there are relatively few studies on the chemical composition and pharmacological activity of A.longiligulare.Chemical components such as volatile oil, diarylheptane and flavonoids in A.longiligulare may be potential anti-gastrointestinal ulcer drugs,and a large number of pharmacological tests need to be carried out to collect data to prove its effectiveness.therefore, it is necessary to explore the research methods with lower cost, the relationship between chemical composition and curative effect, and the evidence to prove that it is more reliable.Making use of the good planting conditions of A.longiligulare in Hainan Province, to study and find A.longiligulare with good curative effect and high yield, and devote to the development of tropical medicinal resources.