Table 2.

CIs (combination indices) (eq. 1) and DRIs obtained using CompuSyn software to analyse OVCAR4 ovarian cell viability inhibition resulting from treatment with the combination of vit D (0.0015–0.153 μg/mL) and different geographical sources of P (1–8400 μg/mL) for 48 h

At the level of Effective dose that induce 50% cellular viability inhibition
	CI value	Concentration of each drug alone (μM)		Concentration of each drug in combination (μM)		DRI Vit D	DRI of corresponding P
		IC50 of Vit D (μg/mL)	IC50 of selected geographical species of P (μg/mL)	IC50 of Vit D (μg/mL)	IC50 of selected geographical species of P (μg/mL)
Ger P + Vit D	0.984	0.035	100.355	0.018	47.451	2.11	1.9
Egy P + Vit D	0.866	0.035	86.064	0.014	38.704	2.39	2.22
Fre P + Vit D	0.891	0.035	75.040	0.014	36.989	2.50	2.02

Equation 1, combination index³²: CI = E (ca.) E (da) + E (cb) E (db)

Where; CI = combination index

 E (ca.) = effect for drug a in combination

 E (cb) = effect for drug b in combination

 E (da) = effect of drug a alone

 E (db) = effect of drug b alone