Fig. 5From: Optimization protocol for the extraction of 6-gingerol and 6-shogaol from Zingiber officinale var. rubrum Theilade and improving antioxidant and anticancer activity using response surface methodologyDose-dependent anticancer activity of Z.officinale var. rubrum Theilade rhizome extracts against HeLa cell line (a) and normal cell viability (b). Tamoxifen was used as a positive control. Bars represent standard error of meansBack to article page