ABSTRACT
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.
ABSTRACT
Tuberculosis control is a high priority for the Ministry of Health from Peru. In the present work the inhibitory effect of both metanolic (MeOH) and ethyl acetate (AcOEt) crude extracts and the minimum inhibitory concentration (MIC) of both wild plants and in vitro plantlets of Plumbago scandens L. -Plumbaginaceae- against multidrug-resistance (MDR) strains of Mycobacterium tuberculosis were determined. The plant material was constituted by roots and seeds, collected in the Motupe (Lambayeque) area. The in vitro plantlets were obtained from seedlings and micropropagated by shoot tips and nodal segments in Murashige and Skoog (MS) culture medium. The microbiological material consisting of one control strain and two strains of Mycobacterium tuberculosis resistant to isoniazid (INH) and rifampicin (RIF) was cultivated using the LowensteinJensen culture medium. The MIC values varied from 0,65 to 1,3 mg/mL. Bacterial strains showed more sensitivite to the AcOEt crude extract. The GC analysis of the plant material showed the presence of the naphtoquinone plumbagin and other aromatic compounds. In conclusion, the MeOH y AcOEt crude extracts from roots of the wild plants and MeOH crude extract of in vitro plantlets of P. scandens showed a strong inhibitory activity against MDR strains of M. tuberculosis.
El control de la tuberculosis es un objetivo de alta prioridad para el Ministerio de Salud del Perú. En el presente trabajo se determinó el efecto inhibitorio de los extractos crudos metanólico (MeOH) y de acetato de etilo (AcOEt), expresados como concentración mínima inhibitoria (CMI) de plantas silvestres y plántulas in vitro de Plumbago scandens L. (Plumbaginaceae) sobre cepas multidrogoresistente (MDR) de Mycobacterium tuberculosis. El material vegetal estuvo constituido por raíces de plantas silvestres, en tanto que las plántulas in vitro fueron obtenidas de semillas y micropropagadas en medio de cultivo Murashige y Skoog (MS). El material microbiológico, constituido por una cepa control y dos cepas resistentes a isoniacida (INH) y rifampicina (RIF), fue cultivado en medio de cultivo Lowenstein-Jensen. Los valores CMI variaron entre 0,65 y 1,3 mg/mL, mostrándose más sensibles las cepas bacterianas frente al extracto crudo de AcOEt de plantas silvestres. El análisis cromatografía de gases (GC) determinó la presencia de la naftoquinona plumbagina y otros compuestos aromáticos. En conclusión, los extractos crudos de MeOH y AcOEt de raíces de plantas silvestres y extracto crudo de MeOH de plántulas in vitro de P. scandens ejercieron una fuerte acción inhibitoria sobre cepas MDR de M. tuberculosis.