Table 6 Threshold inhibitory concentration (IC50) of crude aqueous and methanol extracts of C. dependens and ascorbic acid standard on hydrogen peroxide radicals

Extracts

Threshold inhibitory concentration (*IC50)

Mathematical model

Equation

R2

CDRM

0.90 ± 0.09

Sigmoid (a, b, c)

$$y=\frac{a}{1 +\mathrm{exp}\left(-\left(\frac{x-{x}_{0}}{b}\right)\right)}$$

0.931

CDLM

1.17 ± 0.17

Sigmoid (a, b, c)

$$y=\frac{a}{1 +\mathrm{exp}\left(-\left(\frac{x-{x}_{0}}{b}\right)\right)}$$

0.920

CDSM

1.16 ± 0.15

Sigmoid (a, b, c)

$$y=\frac{a}{1 +\mathrm{exp}\left(-\left(\frac{x-{x}_{0}}{b}\right)\right)}$$

0.915

CDRA

0.71 ± 0.07

Sigmoid (a, b, c)

$$y=\frac{a}{1 +\mathrm{exp}\left(-\left(\frac{x-{x}_{0}}{b}\right)\right)}$$

0.915

CDLA

0.93 ± 0.11

Sigmoid (a, b, c)

$$y=\frac{a}{1 +\mathrm{exp}\left(-\left(\frac{x-{x}_{0}}{b}\right)\right)}$$

0.911

CDSA

0.59 ± 0.11

Sigmoid (a, b, c)

$$y=\frac{a}{1 +\mathrm{exp}\left(-\left(\frac{x-{x}_{0}}{b}\right)\right)}$$

0.810

AA

0.38 ± 0.01

Logistic dose response (a, b, c)

$$y=\frac{a}{1 +{\left(\frac{x}{b}\right)}^{c}}$$

0.999

1. CDRM, C. dependens root methanol; CDLM, C. dependens leaves methanol; CDSM, C. dependens stem methanol; CDRA, C. dependens root aqueous; CDLA, C. dependens leaves aqueous; CDSA, C. dependens stem aqueous; AA, ascorbic acid
2. *IC50 is the concentration of extract or standard that scavenged 50% of the generated free radicals