Rose geranium essential oil as a source of new and safe anti-inflammatory drugs

Figures & data

Table 1. Chemical profile of rose geranium essential oil extracted by steam distillation

No.	Compounds^a	RI	Content%
1	α-Pinene	926	0.85
2	Linalool	1,125	4.52
3	cis-Rose oxide	1,129	0.92
4	trans-Rose oxide	1,131	0.36
5	Menthone	1,156	4.21
6	Citronellol	1,167	29.13
7	Geraniol	1,271	12.62
8	Citronellyl formate	1,275	8.06
9	Geranyl formate	1,300	3.46
10	Citronellyl acetate	1,342	0.43
11	α-Copaene	1,356	1.13
12	Geranyl acetate	1,366	1.58
13	Caryophellene	1,391	1.76
14	Citronellyl propanoate	1,444	0.66
15	α-Agarofuran	1,545	0.4
16	Geranyl N-butyrate	1,562	2.02
17	Phenylethyl tiglate	1,584	1.26
18	10-epi-gamma-Eudesmol	1,619	3.31
19	Citronellyl tiglate	1,667	0.48
20	Geranyl tiglate	1,700	7.14
	Total identified		83.45
	Oxygenated monoterpenes		76.85
	Monoterpene hydrocarbons		1.13
	Oxygenated sesquiterpenes		3.31
	Sesquiterpene hydrocarbons		2.16

RIs (retention indices) were calculated on the HP-5 MS column relative to C7-C28 n-alkanes.

a Compounds listed in order of elution from an HP-5 MS column.

Table 2. Effect of rose geranium essential oil on carrageenan-induced paw edema in mice (n=6)

Treatment	Dose (mg/kg)	Thickness of the left hind paw (mm), mean±SD	Inhibition of paw edema (%)
Negative control	20	3.1±0.15^d	–
RGEO	400	3±0.05^c	30.76
RGEO	200	2.88±0.11^b	38.46
RGEO	100	2.81±0.17^a	73.07
Diclofenac	50	2.76±0.12^a	80.76

Groups if mice were pretreated with vehicle (control group, 20 mg/kg, p.o., n=6) diclofenac (50 mg/kg) or rose geranium essential oil at doses of 100, 200 and 400 mg/Kg (p.o., n=6/group) 30 min before carrageenan-induced paw edema. Means within the same column followed by the same small letter are not significantly different (P>0.05) according to ANOVA one-way analysis followed by Tukey's post hoc multiple comparison test.

Table 3. Topical application of rose geranium essential oil prevents croton oil-induced ear edema in mice

Treatment	Dose (µl/kg)	Weight edema (mg) mean±SD	Inhibition (%)
Negative Control	50	23.75±7.67^c	–
RGEO	200	11.25±3.30^b	73.52
RGEO	400	8.75±2.21^a	88.23
Diclofenac	40	9.25±3.09^a	85.29

Data are presented as mean (mm)±standard deviation (SD) (n=6 per group).

Means within the same column followed by the same small letter are not significantly different (P>0.05) according to ANOVA one-way analysis followed by Tukey's post hoc multiple comparison test.

Fig. 1 Histopathology sections of mouse ear biopsies representing keratin, epidermal, dermal, and cartilage layers (magnification xl00). Harry's hematoxylin-eosin stained sections were scored as mild (+), moderate (+ + ), and severe (+ + +) for edema and substantial inflammatory mononuclear and/or polymorphonuclear cell infiltration in the dermis inflammation phase. (A) no treatment; (B) rose geranium essential oil treatment: edema (−); inflammatory cell infiltration (+), inflammation phase (±). (C) and (D) croton oil: edema (+ + +); inflammatory cell infiltration (+ + ), inflammation phase (+ + ).

Ke: keratin; Ep: epidermal layer; De: dermal layer; Mu: muscle; Ca: cartilage layer; Od: edema; Pc: polymorphonuclear cell infiltration.