Micropropagation of <i>Uraria picta</i> through adventitious bud regeneration and antimicrobial activity of callus
Uraria picta is extensively used in the Asian traditional systems of medicine. Overexploitation of the species for preparation of the drug Dashmula has led to the plant becoming rare and endemic. In the present investigation, an efficient micropropagation protocol has developed from leaf-derived callus of U. picta . Among the various concentrations of cytokinins (6-benzyladenine—BA; kinetin—Kin; and thidiazuron—TDZ) used, a significantly higher number of shoots per culture (58.8 ± 0.8) was observed on Murashige and Skoog (MS) medium fortified with 4.44 μM BA. The shoot regeneration frequency was sustained upon transfer to the same fresh medium at 4-wk intervals over a period of 2 yr. The medium containing various concentrations of auxins (α-napthalene acetic acid (NAA) or indole-3-acetic acid (IAA)) showed callus interspersed root formation; however, MS basal medium containing 3% sucrose revealed direct root induction from in vitro raised shoots. The acclimatized in vitro grown plants showed almost 98% survival upon transfer to soil in earthen pots and grown ex vitro . Randomly amplified polymorphic DNA analysis of 25 arbitrarily selected regenerants and mother plants revealed 100% uniformity and true-to-type nature of the regenerants. Methanolic extracts of callus showed strong antibacterial activity against pathogenic bacteria as compared to leaf and root extracts of in vitro raised plants and wild plants, suggesting the presence of higher concentrations of active chemical constituents (isoflavanoids) in callus cultures of U. picta .