Physical characteristics and yield of plant extracts
After extraction with methanol the yields expressed as percentage (i.e. mg extracted from 300 mg of dry material) were obtained. The yields obtained were given in Table 1.
Table 1: Physical characteristics and yields of the plant extracts
Scientific name
|
Plant part used
|
Extract solvent
|
Weight of powder
|
Weight of extract
|
Yield
|
Extract color
|
Extracts consistency
|
C. aurea
|
Leaf
|
Methanol
|
300g
|
12g
|
4%
|
Redish green
|
Semi-solid
|
S. molle
|
Leaf
|
Methanol
|
300g
|
18g
|
6%
|
Dark green
|
Semi-solid
|
In Vitro louscidal activity of plant extracts
In vitro louscidal activity test of Calpurnea aurea crude extract showed that the mortality of lice was gradually increased with increase post-exposure time and the concentration of the extracts as shown in figure 1.
The mean mortality of lice treated with different concentrations of the crude extract of Calpurnea aurea is shown in Table 2. The result has revealed that all concentrations of the extract result in the mortality of lice. Analysis of mortalities of lice in different concentrations of the plant extracts at different times of post-exposure reveals no significant difference (P > 0.05) between 200 and 100 mg/ml concentration of the extract as compared to the positive control, diazinon 0.1%. Higher concentrations (200 and 100mg/ml) of the extract showed significant (P < 0.05) difference in mortality of lice compared with lower concentrations (12.5 and 6.25mg/ml) of the extracts. In addition, more than 50% of lice mortality was observed as early as 3hr after applying the extract at the concentrations of 200 and 100 mg/ml. No mortality of lice was found in the negative control group (treated with distilled water). After 6hrs, moderate mortality percentage up to 73.3% and 80% were recorded on lice exposed to 100 and 200 mg/ml concentrations, respectively. After 12 hr and 24hr time exposure, 200 and 100mg/ml concentrations of Calpurnea aurea extract showed 93.3%, 86.6% and 100%, 96.6%, lice mortality, respectively. The moderate and strong lice mortality percentage (73.3% and 86.6%) were recorded after 24 hr at the middle concentration (50 and 25mg/ml) respectively. On the other hand, lower concentrations (12.5 and 6.25 mg/ml) of the extract had weak (60% and 43.3%) louscidal activity against L. vituli after 24hrs of exposure respectively (Table2).
Table 2: Louscidal activities of different concentrations of the extract of Calpurnia aurea on Linognathus vituli at different times of exposure.
Concentration (mg/ml)
|
Mean mortaity (%) + SE
|
|
30 min
|
1hr
|
2hr
|
3hr
|
6hr
|
12hr
|
24hr
|
|
|
|
|
|
|
|
200
|
23.3±3.3a
|
36.6±3.3a
|
46.6±3.3a
|
56.6±3.3a
|
80±0.0a
|
93.3±3.3a
|
100±0.0a
|
100
|
13.3±3.3a
|
26.6±3.3a
|
36.6±3.3a
|
53.3±3a
|
73.3±3.3a
|
86.6±3.3a
|
96.6±3.3a
|
50
|
10±0.0a
|
13.3±3.3b
|
16.6±3.3b
|
33.3±3.3ba
|
56.6±3.3b
|
76.6±3.3a
|
86.6±3.3a
|
25
|
6.6±3.3ba
|
10±0.0b
|
16.6±3.3b
|
26.6±3.3bc
|
36.6±3.3b
|
53.3±3.3ab
|
73.3±3.3b
|
12.5
|
3.3±3.3ba
|
6.6±3.3b
|
6.6±3.3b
|
16.6±3.3bc
|
33.3±3.3b
|
46.6±3.3ab
|
60.0±5.7b
|
6.25
|
0±0.0ba
|
3.3±3.3b
|
6.6±3.3b
|
13.3±3.3bc
|
23.3±3.3ba
|
33.3±3.3ab
|
43.3±3.3b
|
Diazinon 0.1%
|
13.3±3.3a
|
20±0.0a
|
36.6±3.3a
|
46.6±3.3a
|
76.6±3.3a
|
90±0.0a
|
96.6±3.3a
|
Distilled H2O
|
0±0.0b
|
0±0.0b
|
0±0.0b
|
0±0.0ab
|
0±0.0bc
|
0±0.0b
|
0±0.0b
|
Means followed by the same letter on the same column are not significantly different (P > 0:05)
SE- standard error, hr- hour
In vitro louscidal activity test of Schinus molle crude extract showed that the mortality of lice was gradually increased with increase post-exposure time and the concentration of the extracts as shown in figure 2.
The different concentrations of methanol extracts of S. molle leaf extract were evaluated for their louscidal properties against L. vitulli. The mean mortalities of lice treated with different concentrations of the extract are shown in table 3. The results showed that all concentrations of methanolic extract of S. molle have no louscidal activity at 30 minutes. However, after 12hrs of exposure, higher mortality percentage (> 50 %) was recorded on lice exposed to 200, 100 and 50 mg/ml concentrations of the extract. All concentrations of the extract showed a statically significant difference (P < 0.05) in their louscidal activity at different times of exposure, except 200 and 100mg/ml concentration of the extract after 24hr exposure as compared to the positive control. Accordingly, after 24hrs of exposure to 200 and 100 mg/ml concentrations showed mortality of 90.0% and 83.3%, respectively. In contrary, lower concentrations (12.5 and 6.25 mg/ml) of the extract showed no louscidal activity up to 3hr and had little or weak louscidal activity ranging from 36 to 40 % mortality against L. vituli after 24hrs of exposure. The highest concentrations (200 and 100mg/ml) have showed strong efficacy of lice mortality up to 90% and 83.3%, respectively. Compared to the negative control (distilled water) all concentrations of the extract showed high mortality of lice (Table 3).
Table 3: Louscidal activities of different concentrations of the extract of Schinus molle on Linognathus vituli at different times of exposure
Concentration (mg/ml)
|
Mean mortality (%)±SE
|
|
30min
|
1hr
|
2hr
|
3hr
|
6hr
|
12hr
|
24hr
|
200
|
0±0.0a
|
6.6±3.3a
|
10±0.0a
|
16.6±3.3a
|
46.6±3.3a
|
70±5.7a
|
90±5.7a
|
100
|
0±0.0 a
|
3.3±3.3a
|
6.6±3.3a
|
13.3±6.6a
|
36.6±3.3a
|
56.6±3.3a
|
83.3±3.3a
|
50
|
0±0.0 a
|
3.3±3.3a
|
3.3±3.3a
|
10±0.0a
|
23.3±3.3ba
|
50±5.7a
|
66.6±3.3a
|
25
|
0±0.0 a
|
0±0.0a
|
3.3±3.3a
|
6.6±3.3a
|
20±0.0ba
|
30±5.7b
|
56.6±3.3b
|
12.5
|
0±0.0 a
|
0±0.0a
|
3.3±3.3a
|
3.3±3.3a
|
16.6±3.3ba
|
23.3±3.3b
|
40±5.7b
|
6.25
|
0±0.0 a
|
0±0.0a
|
0±0.0a
|
3.3±3.3a
|
10±5.7ba
|
23.3±3.3b
|
36.6±3.3b
|
Diazinon 0.1%
|
16.6±3.3b
|
20±5.7b
|
30±5.7b
|
43.3±3.3b
|
70±5.7b
|
83.3±3.3a
|
93.3±3.3a
|
Distilled H2O
|
0±0.0 a
|
0±0.0a
|
0±0.0a
|
0±0.0a
|
0±0.0bac
|
0±0.0ba
|
0±0.0ba
|
Means followed by the same letter on the same column are not significantly different (P > 0:05)
SE- standard error, hr- hour
Toxic effect
Table 4 shows the results of the toxic effects of the plant extracts against Linognatus vituli. Accordingly, toxicity varied with the plant extract and adult lice feeding time. After 24 hours of exposure to the extracts, the highest mortality was recorded for extracts from C. aurea with LC50 values of 8.83 mg/ml compared to S.molle with LC50 values of 16.68 mg/ml.
Table 4: Louscidal activity of plant extracts against Linognathus vituli after 24hr of exposure
Plant extract
|
χ2
|
Regression equation
|
LC50(mg/ml)
(95% CI)
|
LC90 (mg/ml)
(95% CI)
|
LC99 (mg/ml)
(95% CI)
|
C. aurea
|
4.79
|
y = 1.63x -1.54
|
8.83 (5.06,12.61)
|
53.83 (36.63,101.55)
|
235.04 (119.00,859.61)
|
S. molle
|
5.12
|
y = 1.12x - 1.37
|
16.68 (9.29,25.15)
|
230.42 (120.52,815.50)
|
1959.42 (610.93,22,159.65)
|
LC50 LC90 and LC99 are lethal concentration that kills 50%, 90% and 99% of the ingesting lice respectively, 95%CI is the 95% Confidence Interval of the estimate, χ2 chi-square values.
The log (concentration)-mortality trends of C. aurea and S. molle shows, the gradual increase in mortality of lice as the log (concentration) value increases (Figure 3).