Enhancement of rhamnetin production in Vernonia anthelmintica (L.) Willd. cell suspension cultures by eliciting with methyl jasmonate and salicylic acid.

Vernonia anthelmintica (L.) Willd. belongs to the family Asteraceae and has anthelmintic, anti-diabetic, diuretic and anti-asthmatic properties. Present study describes the production of rhamnetin: an O-methylated flavonol with anti-oxidant and anti-inflammatory activities; in cell suspension cultures of V. anthelmintica. Suspension cultures were established from cream coloured friable calli initiated from leaf explants and cultured in liquid MS medium supplemented with combinations of IAA (1.5 mg L-1) and BAP (1.5 mg L-1). After 20 days of cell suspension culture, the initial inoculum size of 0.5 g was increased to 1.05 g 100 mL-1 dry weight at exponential phase. When the culture was treated with 0.8 mM methyl jasmonate for 6 days; 2.2 fold accumulation of rhamnetin production was obtained on a dry weight basis compared to unelicited control. Likewise, the elicitation with salicylic acid 1 mM for 6 days brought about 2.7 fold rhamnetin production compared to unelicited control. The rhamnetin content in dried leaf tissue of field grown plants was found to be 0.143 mg g-1. Elicitation with methyl jasmonate and salicylic acid brought about 7.7 and 9.4 fold increments in rhamnetin production, compared to leaf tissue of field grown plants on a dry weight basis.