3. FOOD ChEMISTRy & bIOTEChNOLOGy 3.1. Lectures

Chem. Listy, 102, s265–s1311 (2008) Food Chemistry & Biotechnology
P48 PRELIMINARy STuDIES ON ThE
ANTIFuNGAL ACTIVITy AND
COMPOSITION OF ThE hExANE ExTRACT
OF ThE bRAZILIAN CHeNOPODiuM
AMbrOsiOiDes L.
GULAB nEWAnDRAM JHAM, CAROLInA
MARAnGOn JARDIM, OnKAR DEV DHInGRA and
MARCELO MOREIRA FREIRE
Federal University of Viçosa (Universidade Federal de
Viçosa), Department of Chemistry, Minas Gerais, 36571-
000, Brazil,
gulab@ufv.br
Introduction
Extracts of several edible botanicals are reported to have
antifungal activity. However, little work has been carried out
to manage fungal deterioration of stored products by plant
derived bioactive compounds.
Epazote (Chenopodium ambrosioides L.) is an herb
native to South America and although there are a few reports
on fungicidal properties of its dichloromethane extracts 1,2 , no
studies have been conducted on its chemical compositions.
In this study, we report our preliminary results on antifungal
activity of the crude hexane extract hexane extract (HE) of
the Brazilian epazote against four fungi (Aspergillus flavus,
A. glaucus, A. niger, A. ochraceous) and identification of
volatiles in the hexane extract by gas chromatography (GC)
and gas chromatography combined with mass spectrometry
(GC-MS).
Experimental
P l a n t M a t e r i a l a n d
H y d r o d i s t i l l a t i o n
The epazote leaves were harvested from shrubs in Viçosa,
Minas Gerais, Brazil, and extracted with hexane (200 ml) for
12 h. The organic phase was collected, dried over anhydrous
sodium sulfate; hexane was evaporated in a rotatory evaporator
at 30 °C under reduced pressure, weighed and evaluated.
A n t i f u n g a l A c t i v i t y
The antifungal activity of the hexane extract was tested
on potato-dextrose agar (PDA) with use of poison food assay.
Percent growth inhibition was calculated by dividing radial
growth in the treatment plates by growth in the control plates
and multiplying by 100. The data were analyzed by AnOVA
and the means compared by the Tukey test (p = 0.05).
I d e n t i f i c a t i o n o f C o m p o u n d s
The volatiles in the crude hexane extract were identified
by GC using RI (Kováts retention index) and GC-MS. The
peaks were first identified by GC-MS library system based on
similarity indexes (SI). RI was obtained for most GC peaks.
The final identification was based on the best SI and RI fits
s678
Results and Discussion
Depending upon the fungus an inhibition of 25–100 %
was obtained (Fig. 1.). In this study, at concentration of 0.3 %,
100% inhibition of four important post-harvest fungi was
obtained. The minimum concentration of 0.1 % was reported
for complete inhibition of Rhizoctonia solani 1 .
Fig. 1. Percent radial growth inhibited by crude Chenopodium
ambrosioides hexane extract after 6-day incubation (25 °C) at concentrations
of 0.3 %, 0.2 and 0.1 %. Mean of three replications.
For each concentration the histograms of different fungi, headed
by the same letter do not differ at (p = 0.05). The bars represent
the standard deviation within the treatment. A.f. = Aspergillus
flavus, A.g. = A. glaucus, A.n = A. niger, A.o = A. ochraceous
Table I
Identification, based on gas chromatography (RIs-Kováts
retention indexes) and gas chromatography-mass spectrometry
and % composition of the crude hexane extract of the
Brazilian Chenopodium ambrosioides
Crude hexane extract
Peak no KI % Compound Structure
1 1019 11.2 α-terpinene
2 1026 6.0 p-cymene
3 1031 0.4 benzyl alcohol
4 1247 54.0 (Z)-ascaridole
5 1287 2.3 carvacrol
6 1305 17.3 (E)-ascaridole
Other identified 8.8 – –
compounds
The composition of the hexanic extract has not been
reported in the literature. About 91.8 % of the volatiles in the
hexane extract were identified by GC and GC-MS (Table I,