Molecules and functions of Cornus officinalis bark volatiles

R E G U L A R A R T I C L E


INTRODUCTION
Cornus officinalis Sieb.et Zucc, the original plant is a deciduous tree or shrub, which is mainly distributed in the north of the Yangtze River in China, in the middle and lower hills of the Qinling Mountains, the south of the Funiu Mountain and the Tianmu Mountain in Zhejiang, and its main planting province is Zhejiang, Henan, Shandong, Anhui and other places (Zhao, 1992;Hong, 2003;Han, 2005).Cornus officinalis contains various chemical components such as volatile oils, organic acids and iridoid glycosides, and has a variety of pharmacological activities (Khan, 2018;Hasan, 2018;Howlader et al., 2018).According to traditional Chinese medicine, cornus officinalis has the effect of tonifying liver and kidney, astringent essence, and modern pharmacology research shows that cornus officinalis has various clinical features such as hypoglycemic, anti-bleeding, platelet aggregation inhibition, anti-inflammatory, anti-oxidation, antibacterial and anti-tumor effects (Ren, 2016;Huang et al., 2017;He et al., 2016;Miyazawa et al., 2014;Cao and Lei, 2013).Efficacy.In recent years, the study of its chemical composition has also been carried out in depth (El Toum, 2018;Khan et al., 2018).Studies have shown that in the decontamination study of Bawei Pills, only cornus officinalis has hypoglycemic effect on streptozotocininduced rat model of diabetes (Ma et al., 2014;Qian et al., 2001;Chen et al., 2016) cornus officinalis can kill ascites cancer cells in vitro.Clinically used for radiotherapy, chemotherapy, leukopenia, primary liver cancer, metastatic liver cancer (Telang et al., 2016;Miyazawa and Kameoka, 2014;Telang et al., 2012), etc.; In addition, ethanol extract cornus officinalis can significantly reduce normal blood glucose, serum total cholesterol and triacylglycerol; and cornus officinalis Oleanolic acid has a slight cardiac diuretic effect and is also clinically used to treat acute viral hepatitis (Hsu et al., 2006;Wang et al., 2007;Jang et al., 2014).
In this paper, the bark of cornus officinalis as the research object, the bark was dried and made into powder, and analyzed by TGA-DTG and PY-GC-MS.It provides scientific research on the utilization of cornus officinalis from a new perspective and direction in accordance with.

Experimental materials
Cornus officinalis bark was obtained from Nanyang City, Henan Province, Xixia County Forest Farm.Place the bark in a 100°C oven until absolutely dry.Then use a pulverizer to break the bark as a sample to be tested.

TGA-DTG analysis
The sample of the fruit of Cornus officinalis were analyzed viathermogravimetric analyzer (TGA Q50 V20. 8 Build 34).The nitrogen release rate was 60 ml/min.The temperature program of TG started at room temperature and increased to 300°C at a rate of 5°C/min (Kok et al., 2016;Gornicka and Gorecki, 2010;Trivedi et al., 2017).

PY-GC-MS Analysis
The fruit of cornus officinalis was analyzed viathermal cracking-gas chromatography-mass spectrometry (CDS5000-Agilent7890B-5977A).The carrier gas was high purity helium, the pyrolysis temperature was 500°C, the heating rate was 20°C/ms, and the pyrolysis time was 15s.The pyrolysis product transfer line and the injection valve temperature were set to 300°C; Column HP-5MS; Capillary column (30m×0.25mm×0.25μm); Shunt mode, split ratio of 1:60, shunt rate of 50mL/min.The temperature of the GC program started at 40°C for 2 min, increased to 120°C at a rate of 5°C/min, and then increased to 200°C at a rate of 10°C/min for 15 min.Ion source (EI) temperature of 230°C, scanning range of 28-500amu (Jiang et al., 2017;Xie et al., 2017;Lu et al., 2011;Ross et al., 2009).

Analysis of TGA and DTG
In order to study the thermal decomposition of active ingredients in the bark of cornus officinalis, we conducted a TGA test on the bark.Figure 1 shows the TGA curve and DTG curve of the bark of cornus officinalis.T5wt% and T20wt% represent 5% and 20% of the weight loss, respectively (Hu and Huang, 2000;Shuyi et al., 1998;Lin, 2004).According to the graph of Fig. 1, we can obtain T5wt% and T20wt% respectively at 61°C and 275°C.According to the thermogravimetric curves of the bark of cornus officinalis, the thermogravimetric analysis process is roughly divided into three stages.The first stage is 20-80°C.The main reaction at this stage is the evaporation of part of the water molecules and small molecules with lower boiling points at elevated temperatures.The quality ratio at this stage dropped from 100% to 93%.The mass loss is T7wt%.The DTG curve at this stage gradually increased from a lower value and reached a peak value at 48°C.At this time, the cracking rate reached the fastest, and then began to gradually decline (Arsenovic et al., 2013;Chen et al., 2015;Li et al., 2013).The second phase is 80-200°C.At this stage, a smaller amount of organic molecules begins to decompose, the mass ratio drops from 93% to 90%, and the mass loss is T3wt%.The DTG continued to decline at this stage, with a slight fluctuation at 120°C, and the curve began to rebound after 160°C.The third stage is 200-300°C.As the temperature continues to increase, the organic components continue to undergo severe cracking and the organic components continue to dissipate.The mass ratio dropped from 90% to the final 74%, and the mass loss was T16wt%.At this point, the DTG curve gradually increased, indicating that the rate of cracking continued to increase during this phase.These three stages exhibited different properties and different kinetic parameters and reaction mechanisms, with a final residual mass of 74%.Throughout the three phases, the weight loss in the first phase was 7%, which was mainly due to the evaporation of some moisture molecules that remained; the quality of the second phase remained good and the weight loss was only 3%; after 200°C, the quality began to drop rapidly, and the final remaining 74%.Through the TGA experimental test, the thermal decomposition of the bark of cornus officinalis below 300°C is described, which provides a reference for us.
The total ion chromatograms of the bark of C.officinalis samples studied via PY-GC-MS are shown in Fig 2 .Highgrade resource utilization has been reported by a scholar (Wu et al., 2003;Qingzhi and Peng, 2008;Lou et al., 2018).Furthermore, the relative content of each component has been counted via area normalization.The MS data is analyzed by using the NIST standard MS map and publicly published books and papers, and then identify each component.Moreover, the analytical results of the samples are listed in Table1, respectively.
From Table 1 can be obtained, the identified compounds can be divided into esters, alcohols, carbohydrates, tannins, iridoids, phenolics, ketones, glycosides and organic acids and so on.Among them, Furfural is a colorless, transparent, oily liquid with a special smell similar to benzaldehyde.Exposure to light and air quickly turns red-brown.Easy to evaporate with steam.Furfural is used as a raw material for organic synthesis and is widely used in the synthesis of fine chemicals such as pharmaceuticals, pesticides, veterinary drugs, dyes, spices, rubber chemicals, and preservatives.The largest area of consumption of Furfural is as a raw material for solvents and synthetic resins.Some of Furfural's derivatives have a strong bactericidal capacity and a broad spectrum of inhibition.Furfural, for example, is 5-nitrofurfural, which is condensed with semicarbazide hydrochloride to give furacilillin, a disinfectant antiseptic.At the same time, as a solvent, Furfural can selectively extract the unsaturated components from petroleum and vegetable oils.Furfural is used to extract the aromatic components in lubricating oils and diesel fuels.Improve the quality of these products (Lange et al., 2012;Palmqvist et al., 2015;Mamman et al., 2018;Eranda et al., 2011).
Another compound, phenol, is one of the main components of coal tar.Runge discovered phenol from coal tar in 1834, and Laurent produced crystalline phenol for the first time in 1841.Phenol is an important organic chemical raw material.It can be used to produce phenolic resin, bisphenol A, salicylic acid, pentachlorophenol, 2,4-D, and other chemical products and intermediates in chemical raw materials, synthetic fibers, plastics, Synthetic rubber, pharmaceuticals, pesticides, spices, dyes, coatings and oil refining industries have important applications (Vinson   et al., 2001;Bystrom et al., 2010).Phenol can denature proteins, so it has a bactericidal effect and shows strong antibacterial activity against many microorganisms, certain fungi, and viruses.Dilute solution phenol can be used as a disinfectant antiseptic and was used in surgery (Ogunrinola et al., 1996;Wang, 2007).According to statistics, in the 21 st century, the demand for phenol in major regions such as the United States, Western Europe, and Japan maintained an average annual growth rate of 4.2%.
Maltol, is a white to slightly yellow needle crystal or crystalline powder, with a special aroma of coke cream, and a dilute solution with a strawberry flavor.It is mainly used in the food industry to formulate strawberry, coffee, malt, nuts, herbs and various fruit flavors.Maltol is also an excellent material for the smooth coating of photographic film to prevent spots and streaks.The skin care cosmetics formulated therewith have the effect of inhibiting melanin growth and whitening the skin (Thompson et al., 2006;Ferreira et al., 2003;Ni et al., 2005;Yasumoto et al., 2004;Singh et al., 2007;Zhang et al., 2000;Liu, 2017;Kmita et al., 2018;Hoque et al., 2018;Khan et al., 2018;Cui et al., 2018).

CONCLUSION
From the above studies, it can be seen that the TGA-DTG analysis showed that the weight loss process of cornus officinalis bark was divided into three stages.The first stage is 20-80°C.The reason for the decline in this part of the curve is that the water molecules contained in the leaves and small molecules with relatively low boiling points evaporate as the temperature rises; the second stage is 80-200°C, during which some organic molecules begin to decompose, and the mass ratio is from 93% decline to 90%; final stage at 200-300°C.At this stage, as the temperature continues to rise, the organic components of the component undergo severe cracking decomposition and combustion of other components, the mass ratio drops from 90% to the final 74%, and the mass loss is T16wt%.
In the PY-GC-MS test, 276 peaks were detected in the bark of cornus officinalis and 276 chemical components were identified.The identified compounds can be classified into esters, acids, phenols, tannins, iridoids, soaps, ketones, and glycosides.Among them, Furfural is not only an important organic material in medicine and industry, but also can be used as a solvent to selectively extract unsaturated components from petroleum and vegetable oils.As an important chemical material, phenol can denature protein to make it have a certain bactericidal effect.Maltol is widely used in a variety of fruit flavors in the food industry due to its unique creamy flavor characteristics.At the same time, it also has a good effect of inhibiting melanin growth and whitening the skin.
Through the research and analysis of the volatiles of cornus officinalis bark, we can clearly understand the organic substances it contains, provide reference for the development of medical or industrial food, and provide fuller and more extensive value for cornus officinalis bark, and provides better help.