CHAPTER 2 LITERATURE REVIEW
4.1. Volatile extracts / essential oils
4.1.6 Cytotoxicity of the volatile extracts
4.1.5.5 Fumigation, Contact toxicity
concentration of 1000 µg/ml. There was a significant difference in the means of percentage mortality of the essential oils and of the standard, potassium dichromate (p ≤ 0.05). There was no significant difference in the means of percentage mortality of the essential oils against the brine shrimps between the treatments at (p ≥ 0.05). The LC50 values of the essential oils were greater than 100 µg/ml and lower than 1000 µg/ml. The dry stem oil had the lowest LC50 value followed by the dry leaf oil and the highest LC50value was shown by the fresh leaf oil.
Table 4.19: Percentage mortality of the essential oils of the fresh leaves, dry leaves and dry stem of T. camphoratusagainst brine shrimps.
Percentage mortality
aFresh leaf oil bDry leaf oil cDry stem oil dPotassium dichromate Concentration (µg/ml)
10 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 93.33 ± 5.77
100 6.67 ± 5.77 10.00 ± 0.00 13.33 ± 5.77 100.00 ± 0.00 500 33.33 ± 5.77 36.67 ± 5.77 43.33 ± 5.77 100.00 ± 0.00 1000 66.67 ± 5.77 70.00 ± 0.00 76.67 ± 5.77 100.00 ± 0.00
a. Linear equation: y = 30.14x – 38.88 LC50= 889.0a b. Linear equation: y = 31.79x – 39.98 LC50= 676.78b c. Linear equation: y = 35.35x – 43.55 LC50= 442.99c d. Linear equation: y = 3.31x + 91.13 LC50= 3.75 x 10-12d
4.1.6.2 Cytotoxicityof the volatile extracts T. trilobus var galpinni against brine shrimps
The cytotoxicity of the essential oil of the fresh leaf of T. trilobus var galpinni was determined and the results are shown in Table 4.20. At the highest concentration, the oil showed 43.33% mortality against brine shrimps. The oil showed weak cytotoxicity against the brine shrimps as evidenced by its high LC50 value. There was a significant difference in the means of the percentage mortality of the essential oil and of the reference standard potassium dichromate.
Table 4.20: Percentage mortality of the essential oils of the fresh leaves of T. trilobus var galpinniagainst brine shrimps.
Percentage brine shrimp mortality
aFresh leaf oil bPotassium dichromate Concentration (µg/ml)
10 3.33 ± 5.77 93.33 ± 5.77
100 10.00 ± 10.00 100 ± 0.00
500 30.00 ± 10.00 100 ± 0.00
1000 43.33 ± 5.77 100 ± 0.00
a. Linear equation: y = 19.37x – 20.45 LC50= 4335a b. Linear equation: y = 3.31x + 91.13 LC50= 3.75 x 10-12b
4.1.6.3 Comparison of the brine shrimp cytotoxicity between the essential oil of T.
camphoratusand T. trilobus var galpinni.
essential oils of T. camphoratus. The percentage brine shrimp mortality by the essential oils is compared in Figure 4.21.
The essential oil of T. trilobus var galpinni showed weaker brine shrimp cytotoxicity than the
Figure 4.21.Comparison of the percent T.camphoratus and T. trilobus var galpinni
4.1.6.4 Cytotoxicityof the volatile extracts of
The percentages of the cytotoxicities of the essential oils of the fresh leaf, dry leaf and dry stem of T. camphoratus against human embryonic kidney cells (HEK293) and human hepatocellular carcinoma cells (HepG2) are shown in Table
concentration of 350 µg/ml, the dry stem oil showed the highest cytotoxicity of 48.3% and 52.6% against the HEK293 and HepG2 cell lines respectively. The LC
the essential oils against both cells were
exception of the LC50 value of fresh leaf oil against HEK293 whose LC 1000 µg/ml. For both cell lines, the LC
order of decreasing cytotoxicity was DS > DL > FL. The results revealed that there was no
0 10 20 30 40 50 60 70 80 90 100
FL/1 DL/1
Percent inhibition
Comparison of the percentage brine shrimp mortality by the essential oils of T.camphoratus and T. trilobus var galpinni.
the volatile extracts of T. camphoratususing the MTT assay
The percentages of the cytotoxicities of the essential oils of the fresh leaf, dry leaf and dry against human embryonic kidney cells (HEK293) and human inoma cells (HepG2) are shown in Table 4.21
concentration of 350 µg/ml, the dry stem oil showed the highest cytotoxicity of 48.3% and 52.6% against the HEK293 and HepG2 cell lines respectively. The LC50values obtained for all oils against both cells were between 100µg/ml and 1000 µg/ml with the
value of fresh leaf oil against HEK293 whose LC50
1000 µg/ml. For both cell lines, the LC50values increased in the order DS < DL <
order of decreasing cytotoxicity was DS > DL > FL. The results revealed that there was no
DL/1 DS/1 FL/2 Potassium
dichromate
10 µg/ml
100 µg/ml
500 µg/ml
1000 µg/ml
brine shrimp mortality by the essential oils of
using the MTT assay
The percentages of the cytotoxicities of the essential oils of the fresh leaf, dry leaf and dry against human embryonic kidney cells (HEK293) and human 4.21. At the highest concentration of 350 µg/ml, the dry stem oil showed the highest cytotoxicity of 48.3% and values obtained for all between 100µg/ml and 1000 µg/ml with the
50 value was above values increased in the order DS < DL < FL hence the order of decreasing cytotoxicity was DS > DL > FL. The results revealed that there was no
10 µg/ml
100 µg/ml
500 µg/ml
1000 µg/ml
significant difference at p≥ 0.05 in the action of the essential oils of the dry stem, fresh and dry leaves on each of the human cells used.
Table 4.21: Percentage cytotoxicity of the volatile extracts of T. camphoratus against human embryonic kidney cells and human hepatocellular carcinoma cells.
Percentage mortality
HEK293 HepG2
aFL bDL cDS dFL eDL fDS
C
50 0.5 ± 0.09 9.70 ± 0.08 10.3 ± 0.07 3.90 ± 0.06 14.1 ± 0.04 5.60 ± 0.05 100 8.9 ± 0.05 10.8 ± 0.08 18.4 ± 0.04 9.10 ± 0.02 18.5 ± 0.04 13.8 ± 0.06 150 10.1 ± 0.07 14.8 ± 0.04 20.3 ± 0.04 12.3 ± 0.02 23.9 ± 0.05 23.8 ± 0.05 200 18.2 ± 0.07 25.2 ± 0.07 31.6 ± 0.06 18.2 ± 0.03 31.4 ± 0.03 32.3 ± 0.05 250 22.5 ± 0.03 27.3 ± 0.09 41.4 ± 0.06 25.5 ± 0.06 40.1 ± 0.01 40.6 ± 0.06 300 33.7 ± 0.08 36.5 ± 0.05 43.9 ± 0.04 34.0 ± 0.05 42.1 ± 0.03 47.3 ± 0.04 350 34.1 ± 0.06 46.3 ± 0.06 48.3 ± 0.04 44.0 ± 0.05 52.6 ± 0.02 54.5 ± 0.02
C = Concentration (µg/ml): Data are mean ± SD values of triplicate determinations.
FL = Fresh leaf DL = Dry leaf DS = Dry stem a. Linear equation: y = 40.15x – 71.17 LC50= 1042.15a b. Linear equation: y = 41.19x – 67.40 LC50= 708.28b c. Linear equation: y = 46.86x – 73.80 LC50= 438.44c d. Linear equation: y = 43.86x - 76.72 LC50= 774.80d e. Linear equation: y = 43.95x – 66.11 LC50= 438.39e f. Linear equation: y = 58.31x – 98.78 LC50= 356.07f
4.1.6.5 Cytotoxicityof the volatile extracts of T. trilobus var galpinniusing the MTT assay
The essential oil of the fresh leaf of T. trilobus var galpinniwas not cytotoxic to the HEK293 cell line (Table 4.22). The HepG2 cell line was slightly sensitive to the essential oil as shown by the low percentage mortality values and a very high LC50value of 4.32 x 103 µg/ml.
Table 4.22: Percentage cytotoxicity of the essential oil of the fresh leaf of T.trilobus var galpinniagainst kidney and carcinoma cells.
Percentage mortality
HEK293 aHepG2
Concentration (µg/ml)
100 0 0.13± 0.03
150 0 0.97± 0.04
200 0 4.57± 0.03
250 0 6.75± 0.01
300 0 12.53± 0.03
350 0 18.80± 0.02
a. Linear equation: y = 32.36x – 67.66 LC50= 4.32 x 103a