Increased production of plumbagin in Plumbago indica root cultures by gamma ray irradiation.

CONTEXT

Plumbagin is a major active constituent of Plumbago indica L. (Plumbaginaceae). It possesses various pharmacological activities that have been shown to assist in the treatment of various diseases.

OBJECTIVES

This work is focused on increasing the production of plumbagin in P. indica root cultures using low doses of gamma ray irradiation as an elicitor.

MATERIALS AND METHODS

The effect of low doses of gamma ray irradiation (0, 5, 10, 15, 20, 25 Gy) and ages of the root cultures (0, 5, 10, 15, 20 days) for elicitation of plumbagin production was determined. The stability of the elicited root cultures to produce plumbagin was also determined during three cycles of subculture.

RESULTS AND DISCUSSION

Treatment of the root cultures with a low dose of gamma ray at 20 Gy gave the highest level of plumbagin production (1.04 mg/g DW) when compared to all other treated groups. The appropriate age of the root cultures for maximum production of plumbagin was found to be 10 days. However, treatment of 5-day-old root cultures resulted in a significant increase of dried root biomass that also had a high plumbagin production. Based on the total biomass per culture flask, the amounts of plumbagin produced by the 5- and 10-day-old treated roots were 0.59 and 0.37 mg/250 mL flask, respectively, which were 4.2- and 2.6-fold higher than the level in the control. Subculturing the root cultures until the third generation still showed an increase in plumbagin production without any effects on their growth.