Antimicrobial Activity of Solanum torvum Swart. Against Important Seed Borne Pathogens of Paddy
ABSTRACT Aqueous and Solvent extracts of leaves of S. torvum viz., Petroleum ether, Benzene, Chloroform, Methanol and Ethanol were tested in vitro for antimicrobial activity following the procedures of poisoned food technique and cup diffusion method against some important seed borne pathogens of paddy viz, Pyricularia oryzae, Alternaria alternata, Bipolaris oryzae, Tricoconis padwickii, Dreschlera tetramera, D. halodes, Curvularia lunata, F. oxysporum, F. moniliformae, F. solani and Xanthomonas oryzae. Aqueous extracts of leaves (at 25% concentration) showed 100, 47.44, 60.47, 71.50, 56.11, 63.33, 78.62, 66.66, 47.44 and 46.27% inhibition of the test pathogens respectively. Highly significant antifungal activity was observed in Methanolic and ethanolic extract. The percentage inhibition of the test pathogenic fungi in Methanolic extract was 100% (P.oryzae), 74.42 (A. alternata), 65.68 (B oryzae), 87.62 (C .lunata), 100% (T. padwickii), 63.33 (D.halodes), 60.31 D. (tetramera), 76.01 (F.moniliformae), 59.21 (F. oxysporum), 43.91% (F.solani) and zone of inhibition of Xanthomonas campestris pv oryzae was 18 and 30mm in Methanol and ethanol extract.
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ABSTRACT: Objective: To evaluate the antimicrobial activity of hexane, ethyl acetate and methanol extracts of seeds and fruits of Illicium griffithii (I. griffithii) (Family: Schisandraceae). Methods: The antimicrobial activity of the organic extracts were determined using disc diffusion assay against Gram-positive bacterial strains (three reference cultures and three clinical isolates), Gram-negative bacterial strains (nine reference cultures and six clinical isolates), and six fungi. The primary phytochemical and chemical compositions were analyzed using qualitative chemical analysis and gas chromatography-mass spectrometry respectively. Results: Ethyl acetate extract of fruits was effective against most of the tested reference cultures such as Staphylococcus aureus, Yersinia enterocolitica, Vibrio parahaemolyticus, Bacillus subtilis, Salmonella paratyphi, Enterococcus feacalis, Xanthomonas oryzae and Pseudomonas aerugenosa, whereas methanol extract showed activity only against Staphylococcus aureus, Bacillus subtilis and Xanthomonas oryzae. The hexane and ethyl acetate extracts of fruits were more effective against most of the clinical isolates, whereas methanol extract was effective only against Klebsiella pneumoniae ESBL. The extracts of fruits and seeds did not show any significant antifungal activity against tested fungi. The presence of phenols, tannins, flavonoids, triterpenoids, steroids, alkaloids, saponis and carbohydrates in the different extracts was established. Gas chromatography-mass spectrometry studies on hexane and ethyl acetate extract of fruits resulted in the identification of 31 and 39 compounds respectively. Conclusions: Potent antibacterial phytochemicals are present in ethyl acetate extract of I. griffithii fruits. Further studies are needed to investigate activities of I. griffithii against multidrug resistant bacteria.Asian Pacific Journal of Tropical Disease. 06/2012; volume 2(issue 3):190-199.
Iranica Journal of Energy & Environment 1 (2): 160-164, 2010
IJEE an Official Peer Reviewed Journal of Babol Noshirvani University of Technology
Corresponding Author: V. Lalitha, Department of Studies in Botany and Microbiology, Maharanis Science College for Women,
Palace road, Bangalore, Karnataka State, India. E-mail: Lali76v@rediffmail.com, Tel: +91-9844142520
Antimicrobial Activity of Solanum torvum Swart. Against
Important Seed Borne Pathogens of Paddy
V. Lalitha, K.A. Raveesha and B. Kiran
Department of Studies in Botany and Microbiology,
Maharanis Science College for Women, Palace Road, Bangalore Karnataka State, India
Department of Studies in Botany, Manasagangotri,
University of Mysore, Mysore- 570 006, Karnataka State, India
Department of Microbiology and Biotechnology,
CMR Institute of Management Studies, Kalyan nagar, Bangalore
Abstract: Aqueous and Solvent extracts of leaves of S. torvum viz., Petroleum ether, Benzene, Chloroform,
Methanol and Ethanol were tested in vitro for antimicrobial activity following the procedures of poisoned food
technique and cup diffusion method against some important seed borne pathogens of paddy viz, Pyricularia
oryzae, Alternaria alternata, Bipolaris oryzae, Tricoconis padwickii, Dreschlera tetramera, D. halodes,
Curvularia lunata, F. oxysporum, F. moniliformae, F. solani and Xanthomonas oryzae. Aqueous extracts of
leaves (at 25% concentration) showed 100, 47.44, 60.47, 71.50, 56.11, 63.33, 78.62, 66.66, 47.44 and 46.27%
inhibition of the test pathogens respectively. Highly significant antifungal activity was observed in Methanolic
and ethanolic extract. The percentage inhibition of the test pathogenic fungi in Methanolic extract was 100%
(P.oryzae), 74.42 (A. alternata), 65.68 (B oryzae), 87.62 (C. lunata), 100% (T. padwickii), 63.33 (D.halodes), 60.31
D. (tetramera), 76.01 (F.moniliformae), 59.21 (F. oxysporum), 43.91% (F.solani) and zone of inhibition of
Xanthomonas campestris pv oryzae was 18 and 30mm in Methanol and ethanol extract.
Key words: Seed borne pathogens % Antimicrobial activity % Solanum torvum % Paddy
population relies on plants and plant extracts for
healthcare . The World Health Organisation estimated
The search for naturally occurring materials with
biological activity and the use of naturally occurring
antifungal substances in plant chemotherapy is gaining
more importance . Plants contain hundred or thousands
of metabolites. Medicinal and aromatic plants a gift of
nature are being used against various infections and
diseases in the world since past history . Among the
estimated 2, 50, 000 to 5, 00, 000 plants species, only a
small percentage has been investigated phytochemically
and the fraction submitted to biological screening is even
smaller. Plant kingdom represents an extraordinary
reservoir of novel molecules. Plant derived products have
been used for medicinal purposes for centuries  and
plants have been an important source of medicine for
thousands of years . About three quarter of the world’s
that 80% of the population of developing countries still
relies on traditional medicines . Higher plants are a
treasure house of phytochemicals which serve as valuable
drugs that helped combat several fatal diseases world
over. Increasing resistance of many pathogens to
currently available synthetic pesticides has become a
serious problem around the globe. Because of the strict
requirements of their efficacy, selectivity, toxicology and
general impact on the environment [7, 8]. The presence of
phytochemicals in medicinal plants have attracted a great
deal of attention, concentrated on their role in preventing
diseases . The antimicrobial activity of plants extracts
has formed the basis of many applications in food
preservetions, pharmaceuticals, alternative medicines and
natural therapies. Researchers are increasingly turning
Iranica J. Energy & Environ., 1 (2): 160-164, 2010
their attention to natural products looking for new leads
to develop better drugs against microbial infections .
In Philippines an estimated 1.2 million hectares of crop
land which is roughly 1/4 of the total area under
cultivation has been severely degraded by the application
of synthetic pesticides and chemical fertilizers .
The latest WHO figures suggests that at least 3 million
and perhaps 25 million agricultural workers are prone to
poison each year by pesticides and some 20,000 deaths.
Thus it is necessary to search for natural pesticides for
sustainable agriculture and healthy environment .
Consequently there is an increasing interest in evaluating
other mechanisms of control including the effect of plant
metabolites. Many angiosperm plants are store houses of
effective chemotherapeutants and results of biological
screening of these plants for a wide range of activities
proved that these can be used for treating diseases
[14-17]. One such plant which has shown significant
antimicrobial activity during preliminary screening was
investigation was conducted to test in vitro the
antimicrobial activity against important seed borne
pathogens of paddy.
extracted successively with different solvents viz.,
Petroleum ether, Benzene, Chloroform, Methanol and
Ethanol depending on its polarity using soxhlet apparatus
and it is condensed under reduced pressure in rotary flash
evaporator to serve as mother extract. The extracts were
preserved in airtight brown bottle until further use for
antifungal activity and antibacterial activity assay .
Antifungal Activity Assay: The antifungal activity of
aqueous and solvent extracts was tested against ten
important seed borne fungal pathogens of paddy.
The antifungal activity was tested by poisoned food
a detailed systematic
MATERIALS AND METHODS
Cultures: Important seed borne pathogens of Paddy viz.,
Pyricularia oryzae, Bipolaris
alternata, Tricoconis padwickii, Drechslera tetramera,
D.halodes, Curvularia lunata, Fusarium moniliformae,
F.oxysporum, F.solani and Xanthomonas oryzae were
isolated from infected paddy seeds by standard
procedures  and pure cultures were maintained for
Aqueous Extract: One hundred grams of fresh leaves of
Solanum torvum free from diseases were collected,
washed and macerated with 100ml sterile distilled water in
a waring blender (waring international, new hart-ford, CT,
USA) for 5mins. The macerate was filtered through double
layered muslin cloth and then centrifuged at 4000g for
30 minutes. The supernatant was filtered through
Whatman No.1 filter paper and sterilized at 120°C for
10minutes, which served as mother aqueous extract
(100%). The extract was preserved aseptically in a brown
bottle at 4°C until further use .
Solvent Extract: Fresh disease free leaves were collected,
washed, shade dried and pulverized to obtain fine dry
powder. The dry powder of the plant material was
Antibacterial Activity Assay: The antibacterial activity
of aqueous and solvent extracts was tested against
Xanthomonas campestris pv oryzae by cup diffusion
method . Streptomycin disc (25mcg), Gentamycin
and Co-trimaxazole antibiotics were also tested for
Statistical Analysis: The data were subjected to Tukey’s
HSD analysis. Data on percentages were transformed to
arcsine and analysis of variance (Anova) was carried out
with transformed values. The means were compared for
significance using Tukey’s HSD (P=0.05).
RESULT AND DISCUSSION
Antifungal Activity Assay
Aqueous Extract: The results revealed a significant
inhibitory activity. The percentage inhibition of test
pathogenic fungi in aqueous extract at 25% concentration
was 100% for (P.oryzae), 47.44 for (B.oryzae), 60.47
for (A.alternata), 71.50 for (T padwickii), 56.11 for
(D. tetramera), 63.33 for (D.halodes), 66.66 for
(F.moniliformae), 47.44 for (F.oxysporum) and 46.26 for
(F.solani) (Table 1).
Solvent Extract: Chloroform, Methanol and Ethanol
extracts showed antifungal activity. The activity was
highly significant in Methanol and Ethanol extracts.
The concentration of 1000ppm was effective in
mycelial inhibition of test pathogens (Table 1).
Methanol extract recorded more than 90% and least
43.91 inhibitions of test pathogens at 1000ppm. Ethanolic
extract also revealed significant activity against test
pathogens. Cent percent inhibition observed in P.oryzae
and more than 50% inhibition observed in rest of the
Iranica J. Energy & Environ., 1 (2): 160-164, 2010
Table 1: Effect of Aqueous and solvent extracts of Solanum torvum swart. against important seed borne fungal pathogens of paddy
Chloroform extract Methanol extract
Aqueous extract (25%) 500ppm 1000ppm500ppm
500ppm Organisms1000ppm 1000ppm
F. moniliformae 47.44±0.39
C Values are the means of three replicates ± standard error.
C In column ‘a-h’ means with different letters are significantly different each other.
100.00 ± 0.00
ef effg ef dede
Table 2: Effect of solvent extracts of Solanum torvum against Xanthomonas campestris pv oryzae
Concentration (µ lt) >< zone of inhibition (mm)
10 203040 50 Solvent extracts60 7080 90 100
Standard: Streptomycin -29mm
C Values are the means of three replicate.
Antibacterial Activity Assay: Only Methanolic and
Ethanolic extracts of S.torvum showed the activity
against Xanthomonas campestris pv oryzae at different
concentrations. The antibacterial activity, measured as the
zone of inhibition of Methanolic and Ethanolic extracts of
Solanum torvum and the antibiotics on the pathovar X.
oryzae, shown in Table 2. The maximum zone of inhibition
in Methanolic extract of S.torvum was 19mm at 100µlt
concentration and minimum 10mm at 10µlt concentration.
Ethanolic extract of S.torvum was highly active
compared to methanolic extract against X.oryzae where
zone of inhibition was 30mm at 100µlt concentration and
can be compared with commercial synthetic antibiotic,
where Streptomycin, Gentamycin and Co-trimaxazol
showed 29mm, 35 and 35mm zone of inhibition against X.
oryzae (Table 2). In vitro screening of S.torvum has given
encouraging results, indicating this as the potential
candidate plant for further work on isolation and
characterization of the antimicrobial compound and its
subsequent exploitation for the management of seed
borne pathogens of paddy.
Seeds serve as important microcosm for saprophytic
and pathogenic micro-organisms and paddy seeds are no
exception to this. Fungi and bacteria invade and colonize
paddy seeds at pre and post harvest stages causing
considerable loss in yield and quality . To overcome
the loss due to these seed borne phytopathogenic fungi,
many synthetic fungicides are used, which are effective
and efficient, but often are not ecofriendly due to their
toxicity and biological magnification in food chain.
Similarly to protect the paddy crop from seed borne
phytopathogenic bacteria a few synthetic antibiotics have
to be applied which is generally cost prohibitive and also
not ecofriendly. Consequently, efforts are underway to
evaluate other mechanism of control including the effect
of plant metabolites on plant pathogens to develop
alternative ecofriendly approaches to crop disease
Iranica J. Energy & Environ., 1 (2): 160-164, 2010
The present investigation not only demonstrates the
antimicrobial activity of S.torvum but also reveal that the
extract can significantly control the seed borne
pathogenic fungi and bacteria. The results also indicated
the necessity for further investigation to isolated and
characterize active principle responsible for the activity
and its subsequent exploitation for paddy disease
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