Corrigendum: Coronarin K and L: Two Novel Labdane Diterpenes From Roscoea purpurea: An Ayurvedic Crude Drug - Singamaneni, Venugopal; Lone, Bashir; Singh, Jasvinder; Kumar, Pankaj; Gairola, Sumeet; Singh, Shashank; Gupta, Prasoon (Frontiers in Chemistry, 2021)