A Summary of Studies on the Bark of a National Medicine Choerospondias axillaris

Wenyi WEI, Yongjing SU, Can LI, Gan LUO, Junmiao MO, Wenya LI, Haicheng WEN, Xiaowei HE, Wei WEI

Guangxi University of Chinese Medicine, Nanning 530001, China

Abstract The bark of Choerospondias axillaris is not only an authentic medicine in Guangxi, but also one of the commonly used medicines of many ethnic minorities.This paper intends to study, summarize, and analyze the planting area, harvesting and processing, processing technology, chemical composition, pharmacological action and the establishment and evaluation of quality standard of C. axillaris, in order to provide more reference basis for the development, research and utilization of Zhuang medicine C. axillaris and the establishment of quality standard.

Key words Bark of Choerospondias axillaris, Ethnic medicine, Chromatography, Chemical composition, Quality standard

1 Introduction

The source of the bark ofChoerospondiasaxillarisis the bark ofChoerospondiasaxillaris(Roxb.)Burtt et Hill., a plant in the Anacardiaceae family distributed in Guangxi.C.axillarisis also known asZiziphusmontana(Yunnan, Guangxi, Guangdong, Hubei), Shan’an’guo(Guangxi), Wuyanjingguo(Yunnan, Guangxi, Guangdong), sour jujube(Yunnan, Guizhou, Guangxi).Its bark is often used as Zhuang folk medicine, and has the effects of clearing away heat and detoxification, removing dampness and killing insects.It is mainly used in the treatment of sores, scalds, scrotal eczema, dysentery, leucorrhea, ringworm and so on[1].Through literature research, this paper summarizes the research status of the bark ofC.axillaris, in order to provide some theoretical reference for the research, evaluation and rational use of the bark ofC.axillaris.

2 History

The earliest record ofZ.montanais seen inSupplementtoCompendiumofMateriaMedica: "It originates from Zhaoqing, Guangxi, with leaves like those of mountain plum, fruits like those of litchi, and it can be eaten after it is ripe in September." It is also recorded: "Z.montanais produced in Guangzhou, shaped like a jujube and round, green and yellow in color and sweet and sour in taste." On the basis of the above description ofZ.montana, it is quite similar toC.axillarisand has been included in the 1977 and 1985 editions ofChinesePharmacopoeia.It is recorded inLuChuanMateriaMedica: "It can kill insects, treat sores, ulcers, and furuncles." It is recorded inNanningPharmaceuticalChronicle: "It can clear away heat and detoxify, treat scalds and sores."

The related contents ofC.axillariswere recorded in the Tibetan medicine bookYueWangYaozhen(the Tibetan nameSomaratsa)as early as the beginning of the 8thcentury AD[2].In the latter part of the 8thcentury, Yutuo Yuandangongbu, a master of Tibetan medicine also recorded it in the famous works of Tibetan medicine—TheFourMedicalTantras[3].In the latter part of the 13thcentury, Tibetan medicine was introduced into Mongolia, andFructusChoerospondiatiswas used in clinical treatment of heart disease by Mongolian medicine.It is described inMengyiJingui,JingzhuMateriaMedica,RenyaoBaijingJian,PictureBookofMongolianMedicine(MongolianMedicineCanon), andTraditionalPrescriptionofMongolianMedicine(GuanZheZhiXi)[4].It is recorded in the 1985 edition of thePharmacopoeiaofthePeople’sRepublicofChina:"FructusChoerospondiatisis sweet, sour, heavy and soft.It can activate qi and blood circulation, nourish the heart and calm the mind, and can be used for qi stagnation and blood stasis, tingling in the heart, shortness of breath, restlessness, neurasthenia, insomnia and so on.

C.axillarishas been widely studied in Mongolian medicine since ancient times.Therefore, there are many relevant literature references, but the research on the bark ofC.axillarisis very few, so for the further research and development of Zhuang medicineC.axillaris, it is reviewed in this paper, which is conducive to further research.

3 Planting, harvesting and processing

3.1 PlantingThe Zhuang medicineC.axillarisis mostly planted in the wild, but with the deepening of people’s understanding ofC.axillaris, artificial cultivation has also been carried out in order to meet the needs of research on the comprehensive utilization ofC.axillaris.Most of its ecological environment is at the altitude of 200-500 m, and it likes to be warm, and is suitable for growing at the annual average temperature of 14-20 ℃.When the temperature exceeds 40 ℃, the monthly average temperature is 35 ℃ in the hottest month, and the relative humidity is below 60%, the growth is slow.Biological characteristics are that it likes warm and humid climate, has strong adaptability, grows rapidly, and is not cold-resistant, but resistant to a certain drought.It has lax requirements on the soil, and the neutral to acidic soil is the most suitable[5].In terms of cultivation techniques, seeds are used to propagate, and the fruits are ripe in summer and autumn.After being harvested and dried, the seeds can be sown.There are two kinds of planting methods: seedling raising methods and cultivation techniques.

3.2 Harvesting and processingThe bark ofC.axillarisis called five-eye fruit bark, and can be collected all the year round.After scraping off the rough skin ofC.axillaris, the second layer of skin was dried or decocted and set aside.It is mainly used for detoxifying, eliminating dampness, treating scald, detoxifying, relieving pain and stopping bleeding, and can be used to treat burns, traumatic bleeding, and psoriasis.It is often decocted into thick juice and applied to the affected part to treat burns and scalds, and it can soon dry and scab.If it is dried in the sun and ground into powder for external use, it can treat traumatic hemorrhage.The bark ofC.axillariscan be decocted and applied to the affected part to treat psoriasis.If decoction is taken orally or reserved for enema, acute and chronic bacillary dysentery can be treated.If its decoction is used for external washing, it can treat cystic eczema.It can be directly used or dried in the sun.It was washed and chopped when used.

According to the relevant reference, the bark ofC.axillarisis mainly processed by traditional technology, and the ethanol extract from the bark ofC.axillarisis used in folk practice to treat burns and scald[6].Therefore, a lot of processing of the bark ofC.axillarisis extended on this basis.In modern studies, water decoction has been used to improve the focus of injury and promote wound tissue repair[7], and there has been a relatively mature extraction process for the study of chemical components[8].

4 Study on chemical components

The components in the bark ofC.axillarisare gallic acid derivatives, aromatic compounds, citrinin and jujuboside dihydroflavonoids, flavanes and so on.

4.1 Chemical components of gallic acid derivativesUnder the research and identification of Li Changweietal[9], seven gallic acid-derived compounds were isolated and identified from the bark ofC.axillaris: gallic acid, ethyl gallate, 1-O-galloyl-β-D-glucopyranose, 1,6-di-O-gallyl-B-D-glucopyranose, 1,4-di-O-gallyl-B-D-glucopyranose, 1,4,6-tris-O-galloyl-D-glucopyranose, 1,3,4,6-tetra-O-galloyl-β-D-glucopyranose,etc.

4.2 Aromatic compoundsLi Changwei[10], Zhong Xiaotao[11]etal.used chromatographic separation technology to separate pinocembrin, naringin, chrysin, dibutyl phthalate and tetradecyl trans-ferulic acid.

4.3 Citrinin and jujuboside dihydroflavonoidsThe bark ofC.axillariscontains 7.25%-19.55% tannin[12].Takabashi[13]etal.isolated citrinin and other components from the extract of bark ofC.axillaris.Lu Yongzhenetal.[14]separated and identified three kinds of crystals from the ethanol extract ofC.axillaris: jujuboside, citrinin and crystalline substances to be further studied.

4.4 FlavanesCui Chengbin[15]and Zhong Xiaotao[11]separated chemical constituents from the bark ofC.axillarisby chromatography, and then identified them according to their physicochemical properties and spectral data.Three flavanes were obtained:(+)-catechin,(+)-catechin-7-O-β-D-glucopyranoside and(+)-catechin-4′-O-β-D-glucopyranoside.

4.5 Other ingredientsIn the study of Wu Xianjinetal.[8], β-sitosterol, hexadecanoic acid, n-42 alkanoic acid, daucosterol, quercetin, rutin, luteolin-3′-O-β-D-glucoside were isolated from the active parts of the bark ofC.axillarisby certain techniques and methods.

5 Pharmacological action

5.1 Broad-spectrum antibacterial activityIn the bark study ofC.axillaris, Bi Chaorongetal.[16]determined that 100% water decoction ofC.axillarisbark had a relatively high antibacterial effect on gram-negative bacteria, positive bacteria, fungi and Candida albicans, that is, it had broad-spectrum antibacterial activity.It has a specific effect on the treatment of bacillary dysentery and burns in clinic[17-18].

5.2 Antibacterial activity of flavonoidsLu Yongzhenetal.[13]isolated and identified jujuboside, citrinin and crystalline substances to be further studied from the ethanol extract ofC.axillaris.It was found that it had inhibitory effect onStaphylococcusaureus,Pseudomonasaeruginosa,Escherichiacoliand nitrate negative bacilli.It is reported that citrinin has the effect of dilating blood vessels and lowering blood pressure, can reduce the permeability of capillaries, has certain anti-inflammatory effects, can relieve spasm, expel phlegm and protect vitamin C from oxidation[19-20].It also has a significant cholagogic effect and can increase bile secretion.

5.3 Anti-hypoxia and anti-tumor activityFlavanoids in the bark ofC.axillarishave anti-tumor, anti-hypoxia and antibacterial activityinvitro.The ethanol extract from the bark ofC.axillarishad strong anti-tumor activity such as cytotoxicity and apoptosis induction on mouse breast cancer cell tsFT210[14].At low concentration, it showed apoptosis induction and G2/M phase inhibition activity[10，21-26].The five compounds isolated from them(pinocembrin, naringin, chrysin, dibutyl phthalate and tetradecyl trans-ferulic acid)had different degrees of cell proliferation inhibitory activity on human colorectal cancer cell HCT-15 and human cervical cancer HeLa cells[8].Seven gallic acid derivatives isolated by Li Changweietal.[8]had anti-tumor and anti-hypoxia components at the same time.Cui Chengbinetal.[14]isolated and identified three components with significant anti-hypoxia activity from the extract of n-butanol, in which(+)-catechin and(+)-catechin-7-O-β-D-glucopyranoside had certain anti-tumor activity, as well as a series of other anti-hypoxia and anti-tumor effects.

5.4 Therapeutic effect on burnsThe studies of Nguyen DDetal.[27]have confirmed that the water extract from the bark ofC.axillarishas a good effect on treating burns, which can significantly shorten the healing time of burns and reduce infection.

6 Study on quality standard

The 2020 edition ofChinesePharmacopoeiadoes not include the quality standard ofC.axillaris, and the processing technology is only limited to treating with folk alcohol infusion.At present, the content of various components in the fruit ofC.axillarisis mostly studied, but the content of bark is seldom studied.3.2 kg of dried bark ofC.axillariswas extracted and separated by ethanol[10], 60 g of chloroform extract, 310 g of ethyl acetate extract, 300 g of n-butanol extract and 80 g of water residue were obtained.Lu Yongzhen[13]etal.extracted 6 kg of bark ofC.axillariswith ethanol and obtained 120 g of thick extract.However, most of the studies are focused on the identification of the effective components in the bark ofC.axillaris, and the study of related content determination is relatively few.

7 Conclusions

C.axillarisis a common medicine used by folk Zhuang doctors in Guangxi, and it is used as a single medicine.At present, the chemical constituents of the bark ofC.axillarisare mainly studied by silica gel column chromatography, silica gel thin layer chromatography and gel column chromatographic separation, but the quality standard of the bark ofC.axillarisas a Zhuang medicine is not yet established.Therefore, further study on the relationship between pharmacological effects and components ofC.axillariswill provide a certain reference basis for the research, evaluation and rational use of the quality standard of the bark ofC.axillaris.