In vitro photo-induced cytotoxic activity of Citrus bergamia and C. medica L. cv. Diamante peel essential oils and identified active coumarins

Figures & data

Table 1.  Components of Citrus bergamia Risso & Poit. (Bergamot oil) and C. medica L. cv. Diamante (Diamante oil) essential oils identified by GC-MS analysis.

Compound	I^a	%^b		ID method^c
		Bergamot oil	Diamante oil
Thujene	926	0.4	1.2	I, MS
α-Pinene	936	1.5	2.5	I, MS, Co-GC
Camphene	953		0.9	I, MS
Sabinene	973	1.1	0.4	I, MS, Co-GC
β-Pinene	978	5.4	2.6	I, MS, Co-GC
β-Myrcene	986	1.1	2.1	I, MS, Co-GC
α-Phellandrene	1005		0.2	I, MS
α-Terpinene	1016	0.1	1.2	I, MS, Co-GC
p-Cimene	1025		tr	I, MS
Limonene	1032	38.1	35.4	I, MS, Co-GC
(E)- β-Ocimene	1047	0.1	2.4	I, MS
γ-Terpinene	1059	7.3	24.5	I, MS, Co-GC
cis-Sabinene hydrate	1068		tr	I, MS
cis-Linalool oxide	1088	0.1		I, MS
Terpinolene	1089	0.4	1.5	I, MS, Co-GC
Linalool	1098	6.4	0.6	I, MS
n-Nonanal	1100	0.1	0.2	I, MS
Citronellal	1156		0.3	I, MS
Terpinen-4-ol	1178	0.2	1.5	I, MS
α-Terpineol	1189	0.1	1.1	I, MS
n-Decanal	1205	0.1	0.1	I, MS
Nerol	1232		1.0	I, MS
Neral	1242		4.4	I, MS
Geraniol	1256		0.3	I, MS
Linalyl acetate	1258	28.9		I, MS, Co-GC
Perilla aldehyde	1272		0.2	I, MS
Geranial	1275	0.2	5.5	I, MS
Citronellyl acetate	1360		0.2	I, MS
Neryl acetate	1370	0.8	0.5	I, MS
Geranyl acetate	1388	0.7	0.4	I, MS
β-Elemene	1390		0.1	I, MS
β-Cubebene	1392		0.1	I, MS
α-Bergamotene	1403	0.6	0.1	I, MS
β-Caryophyllene	1418	0.5	0.3	I, MS, Co-GC
trans-β-Farnesene	1441	0.1	0.5	I, MS
β-Santalene	1448		tr	I, MS
β-Bisabolene	1508	0.8	1.2	I, MS
α-Humulene	1454	0.1	0.2	I, MS, Co-GC
γ-Cadinene	1515		tr	I, MS
δ-Cadinene	1524		0.2	I, MS, Co-GC
Caryophyllene oxide	1592	0.2		I, MS
Tetradecanal	1604		tr	I, MS
β-Bisabolol	1676		0.4	I, MS
Eicosane	2000		0.1	I, MS, Co-GC
Docosane	2200		tr	I, MS, Co-GC
Citropten		0.4	0.9	MS, Co-GC
Bergapten		1.7		MS, Co-GC
Identified compounds		97.5	95.3

^aRetention index on SE-30 MS column. ^bMean value, n = 3. Compositional values less than 0.1% are denoted as traces (tr). ^cI, Retention index; MS, mass spectrum; Co-GC: co injection with authentic compound.

Table 2.  Photo-induced cytotoxic activity of Citrus bergamia Risso & Poit. (Bergamot oil) and C. medica L. cv. Diamante (Diamante oil) essential oils, bergapten and citropten at different times of exposure (20-100′) at λ = 365 nm against human melanoma A375 (IC₅₀ µg/mL).

Sample	Control^a	Time exposure irradiation at λ = 365 nm (IC50 µg/mL)
		20′	40′	60′	100′
Bergamot oil	> 100	> 100	> 100	> 100	79.3 ± 2.2
Diamante oil	> 100	> 100	> 100	> 100	89.8 ± 2.4
Bergapten	> 100	71.7 ± 2.9*	51.64 ± 2.1*	32.51 ± 1.8*	9.1 ± 0.6*
Citropten	> 100	> 100	> 100	> 100	> 100
Vinblastine	3.0 ± 0.08	–	–	–	–

Data are expressed as means ± SD. (n = 3).

^aCells treated with sample but none irradiated. One-way ANOVA **p < 0.0001 Dunnet’s Multiple Comparison Test *p < 0.01.

Figure 1.  Comparative photo-induced cytotoxic activity of C. bergamia (Bergamot oil), C. medica cv. Diamante (Diamante oil) and bergapten after 100 min of exposure with UVA (λ = 365 nm) against human melanoma A375 cell line.