Abstract:
Plants have long been used as sources of crude antimicrobial compounds.
Underground, modified storage organs such as tubers, enlarged taproots, and rhizomes are
located in an environment with a high density of microorganisms capable of invasion and
decomposition. These plant structures are equipped with numerous defense mechanisms in
order to survive. The objective of this study was to detect antibacterial activity from the
modified storage organs of S. tuberosum Linn. cv. 'Granola' (Potato), D. carota ssp. sativus
(Hoffm.) Arcang. cv. 'Kuroda' (Carrot), and R. sativus Linn. cv. 'Snowy' / 'Long White，
(Radish) against Staphyloccocciis aureus, Bacillus subtilis, and Escherichia coli. Pure,
undiluted extracts were obtained by pressing grated samples in a presser and sterilized
using Sartorius Minisart® NML Syringe Filters with pore sizes of 0.2jim. The sterilized
extracts from the peelings and fleshy inner tissues of both freshly harvested and market-
purchased potato tubers, carrot and radish roots were tested against S. aureus, B. subtilis,
and E. coli via Disk Diffusion Assay. It was found that the medullary tissue extract of the
market-purchased potatoes possessed antibacterial activity against S. aureus only. Nine
isolates of endophytic bacteria from the market-bought potato were tested and did not show
antibiosis against S. aureus. These results suggest that market-purchased potatoes may be a
potential source of naturally occurring antibacterial compounds that are probably produced
by the plant and not by the endophytic bacteria.
