HPLC–DAD method for comprehensive quality control of Semen Strychni

Figures & data

Figure 1. Typical HPLC chromatograms of standards (lower trace) and samples (upper trace). (A) 327 nm; (B) 240 nm; (C) 254 nm and (D) 264 nm. Peaks: 1, chlorogenic acid; 2, loganin; 3, strychnine; 4, brucine; 5, strychnine N-oxide and 6, brucine N-oxide.

Table 1. Linear regression data, LODs and LOQs of the investigated compounds.

	Linear regression data^a
Components	Regressive equation	r^2	Linear range (μg/mL)	LOD (μg/mL)	LOQ (μg/mL)	Determining range for Semen Strychni (mg/g)
Chlorogenic acid	Y = 1.2974X − 0.0924	0.9999	1.08–108.0	0.17	0.54	0.108–10.80
Loganin	Y = 0.4137X − 0.0415	0.9999	2.2–220.0	0.33	0.83	0.22–22.00
Strychnine	Y = 0.8136X − 0.0504	1.0000	3.0–300.0	0.14	0.48	0.30–30.00
Brucine	Y = 0.5182X + 0.1005	0.9998	2.5–250.0	0.15	0.50	0.25–25.00
Strychnine N-oxide	Y = 0.7844X + 0.0334	0.9998	0.52–52.0	0.16	0.52	0.052–5.20
Brucine N-oxide	Y = 0.6963X − 0.0395	0.9999	0.54–54.0	0.16	0.54	0.054–5.40

^aIn the linear regression data, Y refers to the peak area, X is the concentration and r is the correlation coefficient of the equation.

Table 2. Precision, repeatability, stability and accuracy data of the analytes.

		Precision (RSD, %)				Accuracy (n = 3)
Components	Spiked (μg/mL)	Intra-day (n = 6)	Inter-day (n = 3)	Repeatability^a (RSD, %, n = 6)	Stability^a (RSD, %, n = 7)	Mean (%)	RSD (%)
	2.56	2.23	3.47			97.3	2.99
Chlorogenic acid	25.6	1.81	2.62	1.20	0.91	102.1	2.45
	86.4	1.49	1.24			100.9	2.41
	4.4	3.17	4.26			97.3	1.98
Loganin	44	2.92	3.55	3.69	4.31	96.5	4.18
	176	1.73	2.58			101.4	4.04
	5.6	1.84	2.53			100.7	1.29
Strychnine	56	1.47	3.25	0.62	0.65	101.8	1.08
	224	0.72	1.09			98.7	1.26
	5	2.11	2.81			97.5	1.64
Brucine	50	1.38	2.16	0.71	0.94	102.8	1.43
	200	0.93	0.78			100.8	1.26
	1.04	2.94	4.55			104.4	4.26
Strychnine N-oxide	10.4	1.82	3.53	2.86	2.25	95.6	4.65
	41.6	2.1	3.2			97.0	3.82
	1.08	3.14	4.19			96.7	3.45
Brucine N-oxide	10.8	3.26	2.12	1.47	1.01	97.5	3.42
	43.2	1.12	2.56			98.3	2.26

^aTested by using the extracted solution of sample one.

Table 3. Contents of the six active compounds in different parts of Semen Strychni.

						Strychnine	Brucine
Source		Chlorogenic acid (mg/g)^a	Loganin (mg/g)^a	Strychnine (mg/g)^a	Brucine (mg/g)^a	N-oxide (mg/g)^a	N-oxide (mg/g)^a
	Whole seed	2.03 ± 0.09	0.97 ± 0.04	17.65 ± 0.32	9.91 ± 0.18	0.177 ± 0.005	0.197 ± 0.004
Sample 1^b	Seed coat	0.37 ± 0.01	1.49 ± 0.06	10.06 ± 0.22	7.82 ± 0.11	0.222 ± 0.005	0.271 ± 0.004
	Seed leaf	1.95 ± 0.08	10.09 ± 0.41	11.76 ± 0.19	10.94 ± 0.25	0.171 ± 0.004	0.197 ± 0.003
	Endosperm	2.19 ± 0.10	0.85 ± 0.03	22.55 ± 0.38	12.72 ± 0.27	0.145 ± 0.003	0.213 ± 0.002
	Whole seed	2.06 ± 0.07	1.58 ± 0.05	16.39 ± 0.27	9.45 ± 0.15	0.174 ± 0.004	0.148 ± 0.003
Sample 2^c	Seed coat	0.39 ± 0.01	1.70 ± 0.21	9.83 ± 0.16	6.17 ± 0.09	0.238 ± 0.005	0.195 ± 0.003
	Seed leaf	1.86 ± 0.06	9.99 ± 0.34	10.99 ± 0.15	10.64 ± 0.12	0.162 ± 0.003	0.156 ± 0.002
	Endosperm	2.39 ± 0.12	1.55 ± 0.05	22.78 ± 0.34	12.01 ± 0.22	0.132 ± 0.002	0.118 ± 0.002
	Whole seed	2.13 ± 0.06	1.11 ± 0.04	17.44 ± 0.17	10.98 ± 0.31	0.216 ± 0.005	0.211 ± 0.004
Sample 3^d	Seed coat	0.35 ± 0.01	1.79 ± 0.12	11.40 ± 0.23	7.77 ± 0.19	0.296 ± 0.005	0.223 ± 0.005
	Seed leaf	2.15 ± 0.08	11.86 ± 0.41	12.05 ± 0.25	10.10 ± 0.25	0.165 ± 0.002	0.209 ± 0.003
	Endosperm	2.37 ± 0.09	1.01 ± 0.03	18.90 ± 0.33	13.99 ± 0.32	0.194 ± 0.003	0.200 ± 0.005

^aMean ± SD, n = 3.

^bFrom Yunnan (China) in December 2010.

^cFrom Yunnan (China) in November 2011.

^dFrom Burma in November 2011.