In vitro seed germination and elicitation of phenolics and flavonoids in in vitro germinated Trigonella foenum graecum plantlets

Abstract

Abstract Trigonella foenum graecum(fenugreek) is an important leguminous plant which exhibits numerous pharmacological properties due to the presence of many important plant secondary metabolites. This study reports the effects of BAP and NAA on in vitro seed germination of Trigonella foenum graecum and the effect of salicylic acid elicitor on total phenolic and flavonoid content and ultimately antioxidant activity of in vitro grown plantlets. Seeds were cultured on MS media with various concentration of BAP and NAA (0–2 mg/L) added singly and in combinations. Germination percentage, shoot length, number of leaves and root length was recorded weekly for 5 weeks, and a final mean of each parameter was taken. Based on the results 2.0 mg/L BAP produced the highest response in all parameters (germination: 93.33 ± 3.18%, shoot length: 3.26 ± 0.08 cm, number of leaves: 13.73 ± 0.18 and root length: 1.12 ± 0.02 cm). After 5 weeks, plantlets were subcultured on MS media supplemented with BAP 2.0 mg/L treated with various concentrations of salicylic acid (100–400 mM) for 48 h. The control did not contain any elicitor. The plantlets were then oven-dried and extracted using methanol by rotary evaporation and tested for antioxidant activity, phenolics and flavonoids. Salicylic acid concentration of 100 Mm produced the highest response in antioxidative activity (89.84 ± 0.10%) and yielded the highest TPC (16.55 ± 0.21 mg GAE/g extract) and TFC (58.89 ± 4.29 mg QE/g extract) among other elicitor concentrations. Trigonella foenumgraecum plantlets exhibited remarkable antioxidant capacity upon elicitation with lower concentrations of salicylic acid. Hence, it is concluded that low concentrations of salicylic acid could effectively be used as potent elicitor to enhance the synthesis of phenolic and flavonoid compounds in vitro fenugreek plantlets.