RESUMO
A protocol was developed for the micropropagation of Plumbago scandens L. from the shoot tip and node explants.The best response of shoot elongation (10.18±2.01 mm) was observed on MS basal medium supplemented with 0.02 mg/L IAA – 0.02 mg/L GA3. The maximum number of root induction (10.0±2.21) and shoot elongation (8.24±3.24 mm) was observed on medium containing 0.01 mg/L IBA and 0.01 mg/L GA3. The in vitro propagated plants were transferred to soil with 80% survival rate. Profuse compact callus was induced and proliferated from several explants (cotyledons, internodes, hypocotyls and roots) cultured on MS medium supplemented with all the combinations of 2,4-D – GA3 or 2,4-D alone and combinations of IAA – BAP or IAA alone, and the highest percentage of friable callus (90%) were induced in the sections of compact callus using 2.0 mg/L IAA – 0.02 mg/L BAP – 0.5 mg/L GA3.The qualitative determination of chemical constituents in the extracts was evaluated by a gas chromatography coupled to a mass spectrometry, and it was verified the presence of plumbagin only in root extracts but not in in vitro plantlets.The antibacterial activity of root extracts against various pathogenic bacteria, and the minimum inhibitory concentrations (MICs) was determined. Chloroform extracts showed good antibacterial activity against Neisseria gonorrhoeae between 0.4 to 1.0 mg/L with 20.4 to 30.0 mm (diameter zone of inhibition); inhibition against Staphylococcus aureus was moderate, and lower against Escherichia coli. Chloroform extracts had the lowest MICs for N. gonorrhoeae (<0.1 mg/mL per disc), and the activities against S. aureus (MIC 0.2 mg/mL) and E. coli (MIC 0.4 mg/mL) were less pronounced.
RESUMO
Withania somnifera is an important medicinal plant and used to cure many diseases. Indirect regeneration protocol for multiple shoots development was established using nodal explants of W. somnifera from 50-60 days old seedlings. The callus induction was observed from nodal explants, grown on Murashige and Skoog (MS) medium supplemented with various concentrations and combinations of 2,4-dichlorophenoxy acetic acid (2,4-D) and kinetin (Kn). Maximum level of callusing response (80.0%) was recorded on MS medium supplemented with a combinations of 2.0 mg/l 2,4-D and 0.2 mg/l Kn. The callus (greenish compact) was transferred into MS medium containing various concentrations (0.5–2.0mg/l) of 6-benzyl amino purine (BAP) alone and in combination (0.1–0.4mg/l) with indole-3-acetic acid (IAA) for shoot initiation and proliferation. The maximum number of shoots was initiated from callus on 1.0mg/l BAP along with 0.2 mg/l IAA and proliferation of shoots achieved by subsequent subcultures at 4 weeks interval in the same medium. The maximum of 31.4 shoots/explant were achieved in the second subculture. MS medium along with 1.0 mg/l gibberellic acid (GA3) induced maximum elongation (96.7%) of regenerated shoots and MS medium supplemented with 0.8 mg/l indole-3-butyric acid (IBA) induced maximum rooting (96.7%) from elongated shoots. After a hardening period, the plantlets were transferred to the field with 98% of survival.