Pine needles from the Chaamse bossen

To get enough needles and twigs of coniferous trees I had in October / November contacted the management forestry unit Langstraat / Chaam (Staatsbosbeheer). I was allowed on a small scale saplings, which arise spontaneously in places where it ultimately is not desirable, to use to distill.

The huge forest under the Forestry Management Unit is approximately 8 square kilometers and lies south and west of Gilze. It stretches from Ulvenhout / Breda in the west to in the east the village Alphen.

wandelroute Chaamse bossen

This continuous forest was created in the sixteenth century with the construction of the Mastbos by Count Hendrik III of Nassau. At the end of the nineteenth century, the government gave the order to reforestation of large tracts of sandy heathland and  the Chaamse forests arose.

Last januari I had time to hit the woods and cut sprigs of pine trees  for distilling afterwards.

The request was for the Scots pine, Pinus Sylvestrus, this specie is find a lot in Dutch forests.

 I needed a saw and a pruner to cut the branches and trunk into smaller pieces. What remained was a small stump of a young pine tree.

It was not possible to distill the cut twigs the same day

The day after I have filled the column and the top of the alembic with the fresh leaves.

The distillation took a little longer because of the low (outside) temperature. It was about 6 degrees Celsius. This temperature is not suitable for distilling. This appeared in the beginning.

Becaus of the low outside temperature, the steam and the oil particles were rapidly cooled.
The cooling water in the bucket was at the time the distillation started about 5 degrees Celsius.
In the steam distillation of essential oil it is particularly important that you cool down steam and oil particles gradually  to about 40-50 degrees Celsius.

The result is the 'shock' of the oil. The oil forms a greasy film on the wall of the funnel and can no longer be proper separated of the hydrosol (water layer). This was as you call it a learning moment! It was only possible to separate 1 mL in a bottle.

alpha-pineen



L-limoneeen



The pine oil smelled nice but still different than the spruce oil I had made in October.
Fir needle oil contains more L-limonene  than pinene which makes it smell like citrus. Pine Needle Oil is the opposite, it is dominated by the increased concentration of the odor pinene.
Pine oil has a lot of medicinal effects, if you want to know more about it click on : http://www.gielenaroma.nl/index.php?page=nederlands---latijn-d
For me at least enough to distill pine needles once more at higher temperatures in spring!

Biosynthesis of terpenes

The biosynthesis, the way plants make substances themselves, is rather complex. The way in which certain cells in plants (see January 25 post) produce essential oil too. To be able to follow this story some knowledge of chemistry and biochemistry is required.

A plant is using photosynthesis to make glucose. Plants use glucose for combustion or stored as starch. Photosynthesis takes place in the chloroplasts.

The combustion of glucose (glycolysis), which runs a number of steps, gives energy and releases water and carbon dioxide.

These reactions take place largely in the mitochondria. In these reactions, two substances are formed that are important for the formation of terpenes.
Terpenes are the main constituents  of the essential oil.

These two substances are glyceraldehyde-3-phosphate and pyruvate. Through several steps and by specific enzymes is ultimately formed IPP and DMAPP. The following step is the formation of GPP, geranyl diphosphate. See below:

 

IPP stands for isopentenyl pyrophosphate and DMAPP  for dimethylallyl pyrophosphate. There are two places where the formation of IPP and DMAPP reactions take place. Schedule A: in the cytosol (cytoplasm) and Schedule B: in a plastid.

IPP and DMAPP (isoprenes) are the building blocks for the formation of numerous terpenes. 

All terpenes are derived from the condensation of 5 - carbon unit isopentenyl diphosphate (IPP) and its isomer dimethylallyl diphosphate (DMAPP). Depending on the number of isoprene units that are tied together terpenes are classified on the number of C atoms: hemiterpenen (C5), monoterpenes (C10), sesqui-(C15), di-(C20), Sester-, tri-, and tetra-terpenes (C25, C30, C40, respectively).

The above diagram shows how the terpenes from IPP and DMAPP are formed. This is basically how the biosynthesis of terpenes proceeds. (click the left mouse button on the picture or diagram to enlarge)




Biosynthesis of limonene en carvone in caraway fruit

 



Caraway



There are also many species-specific biosyntheses such as in caraway seed. From geranyl diphosphate to the enzyme limoneensynthase limonene (a monoterpene) is formed. Through two other enzymes limonene may again be converted into carvone. This brief story I could write after reading articles about it on the internet.
Articles published on: http://www.plantphysiol.org/cgi/content/full/135/4/1893#top#top
and the many charts on this subject available on the internet
Among others, this thesis research on lavender:
Monoterpene production and regulation in Lavenders (Lavandula angustifolia and Lavandula x intermedia) by Astrid Boeckelmann; downloadable via: https://circle.ubc.ca/bitstream/handle/2429/2804/ubc_2008_fall_boeckelmann_astrid.pdf?sequence=1 

Secretory structures of aromatic plants

To know more about how and where plants produce essential oil I bought the booklet:
'Secretory structures of aromatic and medical plants' 

This book, written by Katerina P. Svoboda and Tomas G. Svoboda, gives sharp microscopic images  of the different structures in the plant responsible for producing oil. There are several oil-secreting structures:

 

 The simplest structure consists of  one single cell. This leaves of the magnolia has individually cells producing essential oils.

 

The system is simple: oil is sampled in the vacuole (in cell) equipped with a membrane. The cells are isolated and have an other internal cellular structure than the cells around it. Biosynsthese of all the constituents of the essential oil takes place in plastids (same type as the organelle chloroplasts) and in the cytoplasm of the oil-producing cell.



There are also plants such as Eucalyptus, who possess a cavity surrounded by a large number of oil producing cells within the plantstructure. These so-called excretory cavities are the place where the plant produced essential oil are being stored.

 secretory cavity in citruspeel

 



Even citrus fruits like orange have such cavities lying in the epidermis of the peel. This also explains that when peeling an orange you smell citruslike odors. 



Lavender oil gland 

In the Labiatae family, and thus all kinds of lavender, you come from a very different structure. On the epidermis of the plants are spherical glands with two cells connected to the epidermis cells.



 Figure 3: Glandular trichomes in Lamiaceae. o=oil drop, sc=subcuticular storage cavitiy, h=head cells (site of terpene biosynthesis), s= stem and b= basal cells. (Modified after Fahn, 1979a)

Stems and flowers of flowering plants are also littered with these glands.

Marjoram SEM photo



Like marjoram (Origanum Majorana) are photographed with a scanning electron microscope (SEM), and below a photo of rosemary.

Such structure also explains that if you touch a plant essential oil is released.
Even if plants like lavender is dryed when sqeeuzed the lavender oil kept in the glands will be released.

 cross section of a needle of a conifer



An even more complex structure are secretory ducts. Such channel-like structure found  for example in the conifers. Such ducts make a connection from the roots of the tree to the leaf, flower and fruit.

 Magnification of ducts in wormwood. There are two ducts here, the one on the left is old enough to have developed a small lumen and epithelium; the one on the right has not yet reached the stage of having a lumen. The arrow points to an area where the cells might be starting to pull apart – the black material between the cells might be the first stages of the breakdown of the middle lamella (there are places in the upper part of this micrograph where there are similar amounts of dark material between cells





 Transverse section of needle leaf of pine (Pinus). The needles of pines and many other conifers have resin canals with complex epithelia.

These channels  are composed of an epithelium which surrounds a central cavity. Some of these cells forming the wall of the cavity will change into secretory epithelial cells.The oils  are biosynthesised within their leucoplasts and move via the endoplasmic reticulum into the cavity. The ducts are relatively close to the surface of the leaf. Not without reason. The smallest animals will take off  immediately after a bite out of a pine needle because of the bitter taste which is given by the resins. This is a protection for conifers.
Who wants something more to read about about plant anatomy: http://www.sbs.utexas.edu/mauseth/weblab