Extraction Optimization of Tinospora cordifolia and Assessment of the Anticancer Activity of Its Alkaloid Palmatine

Table 1

Independent variables and their levels used in the response surface design.

Serial number	Independent variables	Symbols	Factor level
			Low (−1)	Middle (0)	High (+1)
1	Extraction temperature (°C)	𝑋1	30	40	50
2	Extraction time (hours)	𝑋2	16	32	48
3	Extraction cycles (cycle)	𝑋3	4	12	20