Antioxidant, analgesic and anti-inflammatory activities of in vitro and field-grown Iceberg lettuce extracts

Context: Iceberg lettuce is a nutrient rich edible crop containing vitamin B6, thiamin and folate. The increasing demand of natural products is moving the focus towards in vitro plant sources as factories for producing important secondary metabolites. Aims: To evaluate the activities of in vitro propagated callus culture and field-grown of Iceberg lettuce, which can act as an alternate source of bioactive secondary metabolites. Methods: The extracts were made with methanol, n-hexane, ethyl acetate and water for field-grown as well as in vitro cultured Iceberg lettuce plants and evaluated for their medicinal potential both in vitro and in vivo in rats. Results: Total flavonoid and phenolic contents of plant extracts showed strong positive correlation with their antioxidant activities. The highest contents of flavonoids and phenolics were present in the methanolic extract of field-grown leaves. The antioxidant, anti-inflammatory and analgesic activities of examined samples in rats were observed as field-grown leaves extracts > callus extracts > regenerated shoots extracts. However, all of these activities in the extracts of callus culture were comparable to that of field-grown plant extracts. Conclusions: This study showed that field-grown plants are comparably rich source of secondary metabolites, which showed multiple pharmacological activities in a significant way.