BDTACEJE^457
Barosma Serratifolia.
Specific gravity
Optical rotation
0-918 to 0-960
- 12° „ - 36°
In addition to the varieties of Barosma which are used in the prepara-
tion of buchu leaf oil the leaves of other species have lately been met
with on the London market on several occasions. Some years ago,
Sagel reported on leaves of Diosma succulentum var. Bergianum, known
as Karoo Buchu, which are reputed to yield an oil equalling that of
Barosma betulinum in value. In other quarters, however, leaves have
also been noticed of which the oil, by its odour, betrays a composition
differing materially from that of the ordinary buchu leaf oil. The leaves
of Barosma pulchella belong to the latter category. The leaves of Barosma
pulchella have an odour resembling that of citronella oil. The shrub is
a native of Cape Colony.
The leaves, on distillation, yield 3 per cent, of essential oil, having the
following characters:—
Specific gravity
Optical rotation
Refractive index
Acid number.
Ester „ ,,
,, ,, (after acetylation)
0-883
+ 8° 36'
1-4577
18-5
27-2
237
The oil contains citronellal, methyl heptenone, d-menthone, d-citron-
ellol, and a phenol in traces.
The leaves of Barosma venusta yield, according to Jensen,
2
1*1 per
cent, of an oil, having the following characters :—
Specific gravity.
Optical rotation
Refractive index
Acid value
Ester „.
,, ,, (alter acetylation)
Phenols ....
0-8839
+ 0° 30'
1-4967
2-4
13-4
52-8
16 per cent.
The oil contains about 35 per cent, of a terpene, boiling at about 66'5°
at 15 to 18 mm., and having a specific gravity O790 and refractive index
1-4778.
On fractional distillation using a four pear-head, at a pressure of
15 mm., the results were as follows :—
No.
1
2
3
4
5
Per Cent.
T'
20
20
20
30
Boiling-point. Optical Rotation.
to 66-5°
» 73°
„ 90°
„ 96°
over 96°
- 0° 25'
- 0° 45'
+ 0
°
30'
+ 2° 20'
+ 0° 30'
Refractive Index.
1-4785
1-4815
1-489
1-508
1-5135
Specific Gravity.
0-796
0-817
0-848
0-945
0-964
Separation was here not very successful, but the extremely low
density of the first fractions (portions being as low as O79), together
with similar boiling-point and optical inactivity, its instability, and the
1
Chemist and Druggist, 65 (1904), 506, 717. * Pkar. Jour.,^90 (1913), 60.
