Assessment of the antibacterial activity and genetic diversity of three black pepper varieties (Piper nigrum Linn.)
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Date
2013
Journal Title
Journal ISSN
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Publisher
Uva Wellassa University of Sri Lanka
Abstract
Piper nigrum (black pepper) is an important spice to enhance flavor, color, aroma and taste of
food. Black pepper is also considered as a medicinal plant species which is used to treat asthma,
chronic indigestion, obesity, sinus, congestion and fever (Ravindran, 2000). It has an
antibacterial activity further highlighting its medicinal importance (Dorman and Dean, 2000). In
Sri Lanka, black pepper is considered as one of the important export agricultural crops.
However, neither medicinal properties nor the antibacterial effect of pepper in Sri Lankan
pepper germplasm has been studied in detail. In neighboring India, there were reports on the
antibacterial activity of pepper on Bacillus cereus and Bacillus subtilis (Perez and Anesini,
1994). According to Chaudhry and Tariq, (2006) “piperine, ([1-[5-[1, 3-benzodioxol-5-yl]-1-
oxo-2, 4, pentadienylpiperridine), a pungent alkaloid present in black pepper enhances the
bioavailability of various structurally and therapeutically diverse drugs”. The genetic diversity
of pepper germplasm has been studied using Inter-Simple Sequence Repeat (ISSR) markers,
microsatellite markers and Randomly Amplified Polymorphic DNA (RAPD) markers. The
present study was conducted to assess the antibacterial activity of pepper oleoresin (an extract
from pepper) from three varieties of P. nigrum in Sri Lanka and also to assess their genetic
diversity using RAPD markers.
Methodology
P. nigrum samples: three P. nigrum varieties, Panniyur-1, MB12 and GK49 were used for the
analysis. Seeds were collected from these three varieties to extract oleoresin and young leaves
were picked to extract DNA. The samples were collected from Central Research Station,
Department of Export Agriculture, Matale, Sri Lanka.
Preparation of oleoresin: pepper seeds were ground into a fine powder using a mechanical
grinder. Ten grams of powder was weighed and filled into a thimble. The thimble was placed in
a Soxhelt apparatus and was exposed to several cycles of distillation. The concentrated solution
was rotary evaporated to extract the oleoresin.
Evaluation of the antibacterial activity: the antibacterial activity of pepper oleoresin against
Escherichia coli (Ingerson-Mahar and Reid, 2011) and Staphylococcus aureus using agar well
diffusion method. Mueller Hinton agar plates were prepared. The two strains of microbial
solution were prepared with compared to the 0.5 McFarland solution and then they were
spreaded on the agar surfaces. Wells were cut by using sterile cork borer and bottom of the
wells was sealed with a little bit of medium. Pepper oleoresins were loaded in to the wells by
using a micropipette and petri dishes were finally incubated at 37 C for overnight in an
incubator.
Description
Keywords
Agriculture, Export Agriculture, Crop Production, Pepper, Black Pepper