Insecticidal Activities of the Leaf Oils of Eight Cinnamomum. species Against Aedes aegypti. and Aedes albopictus.

Figures & data

Table 1 LC₅₀ (µg ml⁻¹) values of the leaf oils of Cinnamomum. species and standard samples against Aedes aegypti. and Ae. albopictus. fourth instar larvae

Sample	Ae. aegypti.	Ae. albopictus.
C. microphyllum.	6.7 (6.1–7.5)	6.2 (5.5–6.9)
C. mollissimum.	10.2 (9.3–11.2)	8.8 (8.0–9.7)
C. pubescen.	12.8 (10.9–14.9)	7.9 (7.0–8.9)
C. rhyncophyllum.	6.0 (5.5–6.5)	11.8 (10.5–13.3)
C. impressicostatum.	10.7 (9.5–12.2)	9.3 (8.4–10.5)
C. scortechinii.	21.5 (18.9–24.5)	16.7 (15.1–18.4)
C. sintoc.	41.1 (35.9–46.5)	36.5 (31.8–41.2)
C. cordatum.	183.6 (156.3–229.6)	160.8 (138.5–195.3)
Camphor	271.5 (237.8–314.1)	201.3 (181.2–224.2)
Benzyl benzoate	6.8 (6.3–7.5)	6.5 (6.0–7.1)
Benzyl salicylate	6.8 (6.4–7.4)	5.5 (5.1–6.0)
1,8-Cineole	642.4 (577.2–740.4)	216.9 (194.8–240.4)
Eugenol	89.9 (82.4–98.1)	80.8 (74.4–87.9)
Methyl eugenol	350.9 (316.8–383.3)	328.3 (298.0–359.2)
Methyl cinnamate	16.8 (14.9–18.7)	12.7 (11.5–14.1)
Cinnamaldehyde	52.8 (47.2–57.9)	35.5 (32.2–38.9)
Linalool	157.4 (145.3–170.5)	143.0 (132.7–153.9)
Safrole	32.1 (26.3–45.8)	28.0 (23.3–37.1)
Terpineols	183.6 (160.5–215.20)	155.5 (138.5–176.2)
Terpinen-4-ol	220.5 (196.2–246.4)	178.1 (157.6–199.6)
Abate	0.00124	0.00131

Confidence limits 95% between parentheses.

Table 2 Adulticidal effect of the leaf oils of Cinnamomum. species on adult mosquitoes exposed continuously for 1, 2, and 3 h.

	% Mortality
	1 h		2 h		3 h
Concentration (µg ml^−1)	Ae. aegypti.	Ae. albopictus.	Ae. aegypti.	Ae. albopictus.	Ae. aegypti.	Ae. albopictus.
C. microphyllum.
1000	4.4	4.4	31.1	33.3	100	100**
500	0	0	20.0	26.7	75.6	77.8**
250	0	0	8.9	11.1	62.2	64.4
125	0	0	2.2	2.2	53.3	55.6
Control	0	0	0	0	0	0
C. mollissimum.
1000	4.4	4.4	31.1	37.8	100	100**
500	0	0	15.6	20.0	100	100**
250	0	0	6.7	8.9	77.8	80.0
150	0	0	2.2	4.4	42.2	48.9
Control	0	0	0	0	0	0
C. pubescens.
1000	2.2	2.2	31.1	33.3	100	100**
500	0	0	11.1	15.6	73.3	77.8**
250	0	0	6.7	6.7	53.3	55.6
150	0	0	2.2	2.2	44.4	48.9
Control	0	0	0	0	0	0
C. scortechinii.
1000	0	0	20.0	22.2	86.7	88.9
500	0	0	11.1	15.6.	60.0	68.9
250	0	0	4.4	4.4	40.0	46.7
150	0	0	2.2	0	28.9	35.6
Control	0	0	0	0	0	0
C. impressicostatum.
1000	0	0	33.3	33.3	100	100**
500	0	0	15.6	20.0	71.1	77.8**
250	0	0	8.9	15.6	57.8	62.2
150	0	0	2.2	2.2	44.4	48.9
Control	0	0	0	0	0	0
C. rhyncophyllum.
1000	0	0	24.4	28.9	71.1	84.4**
500	0	0	8.9	11.1	66.7	75.6**
250	0	0	6.7	6.7	55.6	60.0
150	0	0	2.2	4.4	33.3	35.6
Control	0	0	0	0	0	0
C. cordatum.
1000	0	0	11.1	15.6	53.3	55.6
500	0	0	4.4	4.4	20.0	17.8
250	0	0	0	2.2	4.4	4.4
150	0	0	0	0	0	0
Control	0	0	0	0	0	0
4% DDT	16.0	45.0	100	100	100	100

*p < 0.05,

**p < 0.005 with respect to control.

Table 3 LC₅₀ values (µg ml⁻¹) of the leaf oils of Cinnamomum. species and standard samples against adult mosquitoes after 3-h exposure period

Sample	Ae. aegypti.	Ae. albopictus.
C. microphyllum.	133.0	118.0
	(110.0–152.0)	(96.0 – 136.0)
C. mollissimum.	146.0	132.0
	(127.0–162.0)	(112.0–150.0)
C. pubescen.	178.0	150.0
	(113.0–232.0)	(87.0–197.0)
	(113.0–233.0)
C. impressicostatum.	167.0	135.0
	(94.0–203)	(74.0–181.0)
C. rhyncophyllum.	243.0	194.0
	(168.0–318.0)	(146.0–239.0)
C. scortechinii.	283.0	237.0
	(233.0–337.0)	(191.0–283.0)
C. cordatum.	934.0	917.0
	(811.0–1130.0)	(802.0–1094.0)
Camphor	433.0	314.0
	(379.0–500.0)	(280.0–351.0)
Benzyl benzoate	109.0	97.0
	(30.0–164.0)	(24.0–149.0)
Benzyl salicylate	119.0	113.0
	(35.0–345.0)	(33.0–320.0)
1,8-Cineole	357.0	310.0
	(313.0–406.0)	(185.0–516.0)
Eugenol	488.0	471.0
	(435.0–552.0)	(264.0–852.0)
Methyl eugenol	190.0	181.0
	(175.0–205)	(167.0–196)
Methyl cinnamate	190.0	181.0
	(175.0–205.0)	(167.0–196.0)
Linalool	554.0	528.0
	(488.0–639.0)	(463.0–612.0)
Cinnamaldehyde	288.0	288.0
	(182.0–456.0)	182.0–456.0)
Safrole	228.0	218.0
	(183.0–278.0)	(179.0–260.0)
Terpineols	645.0	606.0
	(555.0–775.0)	(524.0–721.0)
Terpinen-4-ol	698.0	645.0
	(586.0–875.0)	(543.0–801.0)
DDT	0.06	0.05
	(0.009–0.421)	(0.008–0.377)

Confidence limits 95% between parentheses.

Table 4 Essential oil yield from the leaves of eight Cinnamomum. species

Species	% (on a dry weight basis)
C. rhyncophyllum.	3.5 ± 0.4
C. cordatum.	0.8 ± 0.2
C. mollisimum.	2.8 ± 0.5
C. microphyllum.	3.3 ± 0.2
C. impressicostatum.	7.2 ± 0.5
C. pubescens.	5.4 ± 0.3
C. scortechinii.	0.5 ± 0.1
C. sintoc.	0.5 ± 0.3

Data represent the means ± SE obtained from three experiments.

Table 5 Percentage composition of the essential oils of Cinnamomum rhyncophyllum., C. cordatum., C. microphyllum., C. scortechinii., C. pubescens., C. impressicostatum., C. mollissimum., and C. sintoc.

Compound	RI	RHY	COR	MIC	SCO	PUB	IMP	MOL	SIN
2-Hexenal	860	—	—	—	—	—	—	—	0.1
α.-Thujene	931	0.2	0.2	—	0.7	0.2	0.2	—	—
α.-Pinene	937	3.5	1.7	—	1.7	1.8	3.9	—	—
Benzaldehyde	961	—	—	1.0	—	—	—	0.2	—
Sabinene	976	1.5	1.3	—	2.4	1.7	—	—	—
β.-Pinene	979	2.7	1.1	—	1.6	1.2	3.4	0.1	0.1
Myrcene	990	1.1	1.2	—	2.4	0.8	1.4	—	t
α.-Phellandrene	1001	0.5	2.6	—	0.8	1.7	12.3	—	0.4
α.-Terpinene	1016	0.1	0.6	—	—	—	0.2	—	—
p.-Cymene	1024	0.7	1.5	—	6.8	11.7	7.0	1.9	0.2
Limonene	1029	0.3	2.4	—	—	—	4.8	—	—
β.-Phellandrene	1030	10.0	9.0	—	17.3	1.1	2.2	—	—
1,8-Cineole	1032	—	—	—	—	—	—	1.0	—
δ.-3-Carene	1032	t	—	—	—	—	—	—	—
Benzyl alcohol	1033	—	—	2.1	—	—	—	—	—
(Z.)-β.-Ocimene	1040	—	—	—	—	0.1	0.2	—	—
(E.)-β.-Ocimene	1051	—	—	—	—	—	0.2	—	—
γ.-Terpinene	1062	0.3	1.5	—	0.3	—	0.3	—	—
trans.-Linalool oxide	1071	—	—	—	0.2	—	—	—	—
cis.-Linalool oxide	1075	—	—	—	0.2	—	—	—	—
Terpinolene	1089	t	0.5	—	0.2	—	0.1	—	—
Linalool	1098	0.4	17.3	1.4	16.4	—	0.1	0.6	6.5
Camphor	1144	—	0.4	—	—	—	—	—	—
Isopulegol	1152	—	—	—	0.3	—	—	—	—
Citronellal	1159	—	0.3	—	—	—	—	—	—
Terpinen-4-ol	1178	1.1	7.0	t	6.6	0.6	0.8	0.4	5.3
α.-Terpineol	1188	0.4	3.6	0.1	2.3	0.2	0.4	0.3	3.3
cis.-Piperitol	1198	—	0.2	—	0.3	—	—	—	—
Nerol	1232	—	0.2	—	0.3	—	—	—	—
Geraniol	1260	—	0.8	0.3	0.6	—	—	—	—
Safrole	1289	0.7	0.1	—	0.2	—	0.2	—	23.4
Eugenol	1357	0.1	0.1	—	—	—	—	—	7.6
Methyl cinnamate	1380	4.3	17.1	—	—	1.8	1.0	—	—
β.-Bourbonene	1377	—	—	—	0.3	—	—	—	—
β.-Elemene	1390	—	—	0.1	0.2	—	—	—	1.9
Methyl eugenol	1402	0.2	4.4	—	—	—	—	0.4	—
cis.-α.-Bergamotene	1415	—	—	—	—	—	0.3	0.6	—
β.-Caryophyllene	1419	0.4	0.3	1.2	0.2	—	0.3	—	2.6
trans.-α.-Bergamotene	1435	—	—	—	—	—	0.1	0.1	—
γ.-Elemene	1437	—	—	—	—	—	—	—	1.2
Aromadendrene	1440	—	0.3	0.1	0.4	—	—	—	0.2
α.-Humulene	1454	1.1	0.2	0.6	0.1	0.4	1.0	1.5	1.8
β.-(E.)-Farnesene	1456	—	—	0.2	0.2	0.1	—	—	—
ar-Curcumene	1480	—	—	—	—	—	—	0.1	—
γ.-Muurolene	1480	—	0.2	—	—	—	—	—	13.5
β.-Selinene	1485	0.1	—	0.6	—	—	—	—	—
cis.-β.-Guaiene	1490	0.1	t	—	—	—	—	—	—
β.-Bisabolene	1505	—	—	—	—	—	—	0.2	—
γ.-Cadinene	1514	—	0.1	—	—	—	—	—	0.7
δ.-Cadinene	1522	0.1	0.9	—	0.3	—	—	—	2.7
(Z.)-Nerolidol	1535	—	0.7	—	—	—	—	—	—
Elemol	1552	—	—	—	—	—	—	—	1.0
Spathulenol	1575	0.1	1.6	0.8	1.7	—	—	—	—
Caryophyllne oxide	1583	—	—	—	—	—	—	0.5	1.1
Globulol	1586	—	1.6	1.7	1.2	—	—	—	—
Viridiflorol	1603	—	1.4	—	—	—	—	—	—
β.-Eudesmol	1651	—	0.5	0.4	0.6	—	—	—	—
α.-Eudesmol	1655	—	0.3	—	0.3	—	—	—	—
(E.,Z.)-Farnesol	1746	—	—	0.1	0.3	—	—	—	—
(E.)-Asarone	1678	—	0.1	—	—	—	—	—	—
Benzyl benzoate	1762	70.0	7.6	87.8	13.5	50.2	50.9	87.6	0.2
Benzyl salicylate	1860	—	4.7	—	9.4	23.4	7.5	0.2	—

Percentages were obtained by peak-area normalization on column DB-5, all relative response factors being taken as one; the retention index of compounds on the DB-1 was also determined; RI, retention index; t, trace; RHY, C. rhyncophyllum.; COR, C. cordatum.; MIC, C. microphyllum.; SCO, C. scortechinii.; PUB, C. pubescens.; IMP, C. impressicostatum.; MOL, C. mollissimum.; SIN, C. sintoc..