Determination of the content of p-methoxy cinnamic acid ethyl ester in hawthorn - Master's thesis - Dissertation

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Abstract: Objective: To establish a method for the determination of ethyl p-methoxycinnamate in hawthorn. METHODS: The content of p-methoxy cinnamate in hawthorn was determined by GC. A column with SE-30 as the stationary phase was used with a column temperature of 20 °C. Results: The linear relationship of this method was good (r=0.9995), the average recovery was 97.8%, and the relative standard deviation (RSD) was 1.1% (n=5). Conclusion: This method can control the quality of medicinal materials.

Key words: gas chromatography; hawthorn; p-methoxy cinnamic acid ethyl ester

Hawthorn is a Zingiberaceae plant Kaempferia galanga L. The dried rhizomes, cultivated in Taiwan, Guangdong, Guangxi and Yunnan, are a kind of tradition, with the effect of temperature, digestion and pain relief. In the 2000 edition, the volatile oil content is not less than 4.5% (ml/g), and the ethyl ethy1-P-methoxy-cinnamate is the main component. In this paper, the content of p-methoxy cinnamic acid ethyl ester in hawthorn was determined by gas chromatography. The method is simple and can be used as the quality evaluation index of hawthorn.

1 Instruments and reagents

1.1 Instrument: Puri GC7800 gas chromatograph, ultrasonic cleaner.

1.2 Test: The ethyl-P-methoxycinnamate reference substance was provided by China National Institute for the Control of Pharmaceutical and Biological Products, batch number 0835.9601, and refined by recrystallization. After GC test, the purity was 98% or more. All other reagents were of analytical grade.

1.3 Test samples The medicinal materials are all commercially available. The roots of Kaempferia gal~ga L. are identified by this laboratory. The medicinal materials are crushed and sieved through a 40 mesh sieve.

2 Methods and results

2.1 Chromatographic conditions Column: glass column, 2.1 meters long, 0.3 cm in diameter. The stationary phase was SE-30 and the coating concentration was 10%. Column temperature: 200 ° C, inlet temperature and detector temperature is 250 ° C, carrier gas flow rate is 80 Kpa, hydrogen flow rate is 100 Kpa, air flow rate is 50 Kpa, sensitivity is 10-1. .

2.2 Selection of sample extraction conditions: Ethyl acetate and methanol were used as solvents, and ultrasonic extraction for 30 min resulted in the highest methanol extraction content. The extraction time was investigated and the results were completely extracted in 30 min.

2.3 Linear relationship investigation: Take the p-methoxy cinnamic acid ethyl ester reference substance, add methanol to make a solution with a concentration of 0.5, 1.0, 2.0, 5.0, 10.0 mg / mL, respectively. Each of the above reference solution 2 was accurately aspirated and injected into a gas chromatograph to measure the peak area. The injection amount is the abscissa, the peak area is the ordinate, and the standard curve is drawn. The regression equation is: Y=316412.8X-43265.8, r=0.9995. The results show that the linearity is good at 1-20μg.

2.4 Precision and stability test: The sample of the same concentration was continuously injected 5 times, and the RSD was 0.8% based on the peak area. The samples were injected at regular intervals and the samples were stable within 24 h with an RSD of 1.0%.

2.5 Repeatability test: Take the same sample, weigh 5 parts, and test according to 2.7 “sample determination”, the measured content is 39.3, 39.6, 40.9, 40.2, 40. 3 mg/g, average value 40.1 mg/g, RSD = 1.6%.

2.6 Sample recovery test: Weigh accurately 0.5g of hawthorn samples with known content of ethyl p-methoxycinnamate, add a certain amount of reference substance, and test according to 2.7 "sample determination". The calculated recovery was 97.8%, RSD = 1.1% (rt = 5). The measurement results are shown in Table 1.

2.7 Sample determination: Take about 1g of hawthorn, add 10mL of methanol precisely, weigh the weight, sonicate for 30min, weigh the weight, make up the weight loss, filter, and take the filtrate as the test solution. Take the reference solution (4.0mg/mL) and the test solution for each injection. The results are shown in the table.

3 Discussion

The quality of hawthorn is superior to aromatic aroma and spicy taste. The volatile oil contains 3% to 4% of volatile oil. The main component of volatile oil is ethyl p-methyl cinnamate, so the determination of ethyl methyl cinnamate The content can control the quality of the medicinal materials, and at the same time provide a reference for the improvement of the quality standards of hawthorn.