Isolation and Characterization of an Acyclic Isoprenoid from Linn. and its Antibacterial Potential : - Antimicrobial Activity of Linn. Seeds.

OBJECTIVES

Linn. is a plant well-known for its antimicrobial, antidiabetic and anti-arthritic properties in the Ayurvedic and Siddha system of medicine. This has prompted the screening of this plant for antibacterial activity. The main aims of this study were to isolate compounds from the plant's seeds and to evaluate their antibacterial effects on clinical bacterial test strains.

METHODS

The n-butanolic concentrate of the seed extract was subjected to thin layer chromatography (TLC) and repeated silica gel column chromatography followed by elution with various solvents. The compound was identified based on observed spectral (IR, H NMR, C NMR and high-resolution mass spectrometry) data. The well diffusion method was employed to evaluate the antibacterial activities of the isolated acyclic isoprenoid compound (final concentration: 5 - 15 μg/mL) on four test bacterial strains, namely, (MTCC 96), (MTCC 430), (MTCC 1689) and (MTCC 9829).

RESULTS

Extensive spectroscopic studies showed the structure of the isolated compound to be an acyclic isoprenoid (CHO). Moreover, the isoprenoid showed a remarkable inhibition of bacterial growth at a concentration of 15 μg/mL compared to the two other doses tested (5 and 10 μg/mL) and to tetracycline, a commercially available antibiotic that was used as a reference drug.

CONCLUSION

The isolation of an antimicrobial compound from seeds validates the use of this plant in the treatment of infections. The isolated compound found to be active in this study could be useful for the development of new antimicrobial drugs.