Anticancer activity of aqueous myrrh extract alone and in combination with cisplatin in HeLa cells

Purpose: To study the impact of an aqueous myrrh extract on the proliferation of cervical cancer cells in vitro.
Methods: First, 100 g of ground myrrh resin was boiled in 1000 mL of distilled water for 30 min. Different components of the decoction were identified using gas chromatography–mass spectrometry and high-performance liquid chromatography. The effects of high (20 μg/mL) and low (10 μg/mL) concentrations of cisplatin, serial concentrations of myrrh (20, 40, 60, and 80 μg/mL), and a combination of both were evaluated using cell proliferation assay, DNA fragmentation, and electron microscopy.
Results: All four myrrh concentrations decreased the viability of HeLa cells (16.25 % p < 0.01). A significant further decrease occurred when myrrh was combined with 10 μg/mL cisplatin (11.42 % p < 0.01). This was confirmed by quantifying DNA fragmentation. Ultrastructurally, HeLa cells showed typical apoptosis after treatment with 10 μg/mL cisplatin or a high dose of myrrh. The use of 20 μg/mL cisplatin or the combined therapy resulted in cell necrosis with ruptured cell membranes and autophagosomes. The effect of combined therapy was more lethal than the effect of either of them alone.
Conclusion: Myrrh induces apoptosis and autophagy and enhances the activity of cisplatin in vitro. It is potentially a basis for further studies of other types of cancer cell. The clinical use of myrrh in the palliative therapy of human cervical carcinoma might be justified.

Keywords
Cervical cancer, Cell viability, Chemotherapy, DNA fragmentation, Myrrh, Cisplatin, Cell ultrastructure, HeLa cells