Assessment of genetic fidelity of Dioscorea bulbifera L. and Dioscorea hirtiflora Benth. and medicinal bioactivity produced from the induced tuberous roots

Abstract

Wild tubers of Dioscorea bulbifera (Db) and Dioscorea hirtiflora (Dh) mainly used as sources of famine food and in herbal preparations are often indiscriminately collected in Africa and Asia. Therefore, there is the need to complement wild sourcing of the tubers to promote their conservation. The present study reports in vitro tuberous induction (80%) for the first time from Dh cultured on MS + NAA (2.5 mg/L) with IC50 of 472.5 ± 1.77 µg/mL using DPPH, whereas tuberous root (60%) from Db on MS + Kn (2.5 mg/L) + NAA (0.25 mg/L) had IC50 of 26.97 ± 1.00 µg/mL. Genetic fidelity assessment of in vitro plants compared to the wild plants revealed similar amplicon size of amplified DNA using trnH–psbA and rbcL. Similarly, micromorphological diagnostic features like oil gland, crystals (raphides), trichome and stomata type were obtained from the epidermal peels of the wild and in vitro plants. The ethyl acetate (EtOAc) extract of the flesh of Dh (wild) had the highest catechin content (108.3 ± 0.69 µg/g DW). Protocatechuic acid was highest in the methanol (MeOH) extract of the flesh of Dh (0.42 ± 0.02 µg/g DW), while it was detected in trace amount in the in vitro tuberous roots of MeOH extracts of Dh treated with NAA. The in vitro protocol developed in this study could be employed to multiply Dioscorea bulbifera L. and Dioscorea hirtiflora Benth. to offer genetically stable clones for the optimization of bioactive compounds and germplasms conservation.