Preliminary screening for extraction techniques and bioactive fraction of Coptidis Rhizoma based on microcalorimetry

Figures & data

Figure 1.  The power–time curve of E. coli growth at 37°C without any substance. E. coli was cultured in LB culture medium and monitored using a TAM air isothermal calorimeter, ampoule method at 37°C.

Table 1.  Growth rate constants k₁ and k₂ of E. coli growth at 37°C.

Channel	1	2	3	4	5	6	7	8
k1 (/mill)	0.11206	0.11213	0.11201	0.11195	0.11201	0.11193	0.11192	0.11201
Ra	0.9987	0.9989	0.9971	0.9974	0.9990	0.9981	0.9972	0.9988
k2 (/mill)	0.00891	0.00874	0.00869	0.00885	0.00879	0.00901	0.00905	0.00895
R^a	0.9992	0.9982	0.9988	0.9990	0.9992	0.9994	0.9991	0.9989

^aCorrelation coefficient.

Table 2.  The thermokinetic parameters of E. coli growth at 37°C affected by C. Rhizoma extractions at 2 mg/mL.

Extraction technique	Extraction fraction	k1 (/mill)	k2 (/miu)	tm (miu)	Pm (MW)
	Control	0.11204	0.00932	812.7	1.740
Decoction technique	Water	0.01069	0.00435	818.8	1.354
	Residue	0.01006	0.00473	880.7	1.348
	PE	0.00823	0.00371	861.7	1.218
	CHC13	0.00710	0.00344	928.0	1.183
	EtOAc	0.00664	0.00277	1084.3	1.129
	n-BuOH	0.00552	0.00242	1219.0	1.008
Refluxing technique	Water	0.01081	0.00576	760.7	1.693
	Residue	0.01031	0.00597	758.7	1.652
	PE	0.00872	0.00551	771.0	1.647
	CHCl3	0.00765	0.00543	788.3	1.638
	EtOAc	0.00707	0.00478	820.0	1.548
	n-BuOH	0.00564	0.00461	850.0	1.495
Ultrasound technique	Water	0.01092	0.00861	892.3	1.429
	Residue	0.01056	0.00905	923.6	1.247
	PE	0.00921	0.00826	941.0	1.240
	CHC13	0.00812	0.00702	997.6	1.221
	EtOAc	0.00709	0.00615	1113.0	1.188
	n-BuOH	0.00585	0.00524	908.3	1.163

Figure 2.  The power–time curves of E. coli growth at 37°C affected by C. Rhizoma fractions obtained from (A) decoction, (B) refluxing, and (C) ultrasound techniques. The various factions were (a) control, (b) water extraction, (c) residue, (d) PE fraction, (e) CHCl₃ fraction, (f) EtOAc fraction, and (g) n-BuOH fraction with the final concentration of 2.00 mg/mL in the LB culture medium.

Table 3.  ANOVA results for three extraction groups.

Group	Wilks’ lambda value	F-value	Num DF	Den DF	Pr > F
Decoction and refluxing technique	0.24369860	5.43	4	7	0.0261
Decoction and ultrasound technique	0.84743364	6.32	4	7	0.0362
Refluxing and ultrasound technique	0.76176905	5.55	4	7	0.0075

Table 4.  The thermokinetic parameters of E. coli growth at 37°C affected by n-BuOH fraction of C. Rhizoma.

Extraction technique	c (mg/mL)	k1 (/min)	k2 (/min)	tm (min)	Pm (mW)	I (%)	IC50 (mg/mL)
	0	0.10735	0.00769	836.3	1.733	—
Decoction technique	0.50	0.10669	0.00472	778.0	1.602	38.6	1.68
	1.00	0.10631	0.00453	819.7	1.538	41.1
	1.50	0.10628	0.00404	841.0	1.499	47.5
	2.00	0.10615	0.00375	869.7	1.413	51.2
	2.50	0.10599	0.00315	930.7	1.353	59.0
	3.00	0.10584	0.00261	830.3	1.331	66.1
	3.50	0.10491	0.00212	890.7	1.202	72.4

Figure 3.  The power–time curves of E. coli growth at 37°C affected by n-BuOH fractions of C. Rhizoma got obtained by decoction techniques at concentrations of (a) 0, (b) 0.5, (c) 1.0, (d) 1.5, (e) 2.0, (f) 2.5, (g) 3.0, and (h) 3.5 mg/mL.

Figure 4.  Relationship between inhibition ratio (I) and c. The linear relationship between I and c was good with R of 0.9940. IC₅₀ (1.68 mg/mL) was calculated from this linear relationship.