Abstract:
Experiments were conducted to select suitable solvents for extracting nematicidal and
bacterial chemical compounds from ground fruits of wild cucumber (Cucumis
myriocarpus). Solvents and mixtures tested include 80% hexane: 20% dichloromethane,
80% n-hexane: 20% methanol, 20% n-hexane: 80% methanol, 100% dichloromethane,
80% n-hexane: ethanol, 100% methanol, 100% acetone, 100% toluene, 100% water,
100% ethyl acetate, 100% petroleum ether, 100% n-hexane, total ethanolic extract, 100%
hexane fraction, hexane-ethyl acetate (1:1, v/v) fraction, 100% ethyl acetate fraction and
100% methanol fraction. Selection of the solution with the highest antihelmtic effect was
done through the standard bioactivity tests.
The nematode species used in the bioactivity tests were the root-knot nematode
(Meloidogyne incognita) and the citrus nematode (Tylenchulus semipenetrans). In M.
incognita study, the bioactivity effect ranged from 87% to 95%, whereas in T.
semipenetrans the range was from 83% to 96%. The ethanolic extract and 100% hexane
fraction were the best solvents for use in assessing antihelmintic properties of C.
myriocarpus fruit.
The solvents used in antihelmintic studies, as well as 100% dichloromethane, 100%
water, 100% acetone, 100% toluene, 100% petroleum ether and 100% n-hexane were
tested for antibacterial properties. The bacteria used were a mixture of Bacillus species,
namely, B. litcheniformis, B. laterosporus and B. chitinosporus. Extracts from C.
myriocarpus fruit exhibited antibacterial properties towards Bacillus species. In all tests,
vii
100% dichloromethane and 100% n-hexane were the best solvents for use in assessing
antibacterial properties of C. myriocarpus fruits.
Minimum inhibitory concentration (MIC) of the solvents were determined using the
biotest solutions extracted from 70.1 g C. myriocarpus. The 100% ethyl acetate and
100% petroleum ether had the lowest MIC of 3.13 mg/ml each, whereas in the 500 g
material, hexane-ethyl acetate (1:1, v/v) and 100% ethyl acetate had the MIC of 0.78
mg/ml each.
Results of the study confirmed the antihelmintic properties of C. myriocarpus fruits.
Also, they demonstrated for the first time the antibacterial properties of C. myriocarpus
fruits towards Bacillus species.
