Pittosporum tobira

Pittosporum tobira is an aromatic flowering plant in the Pittosporum family Pittosporaceae with several common names including Australian laurel,Japanese pittosporum,mock orange and Japanese cheesewood.It is native to Japan (Southern Kanto),China,Taiwan, and Korea but it is used as an ornamental plant in landscaping and leaf-cutting throughout the world.

Description

It is an evergreen shrub 10 meters (33 ft) high and 3 meters (10 ft) wide and can grow into a tree.It can also be pruned as a hedge. The leaves are oval with curled edges and can reach a length of 10 cm (4 in).They are tough, hairless, and have a darker,shinier upper surface.Inflorescences are clusters of fragrant flowers that occur at the ends of branches.The flower has five white petals,each about a centimeter long.The fruit is a hairy woody capsule, about 1 cm wide, divided into three valves.Inside are black seeds in a resin pulp bed.

Distribution 

It is native to parts of East Asia,but has been introduced to many parts of the world as an ornamental plant.In China, it is found in Fujian Province and has been introduced in several other places.In Japan,it is distributed in Honshu Island, Kyushu Island,Shikoku Island and Ryukyu Islands.It is also found in Korea and northern Taiwan.It has been introduced to parts of the United States and may be found in California, North Carolina,Georgia,and Florida.It grows in forests, limestone areas, slopes, sandy shores and roadsides, often reaching 1800 m sea level.

Taxonomy and phylogeny

P. tobira is one of more than 200 species in the genus Pittosporum,which also includes kōhūhū and tarata.Phylogenetic studies reveal that Penaeus japonicus,Penaeus glauca,Penaeus ilisi and Penaeus balfour are closely related.

Names and Etymology

The binomial qualifier tobira is derived from the plant's Japanese name.The genus name Pittosporum is derived from the Greek entities pitta (meaning "pitch") and sporos (meaning "seed"), referring to the resinous substance that surrounds the seed.In Japan and China, where it is native, it is known as tobera (テベラ in Japanese) and Pittosporum tree (Pittogonia in Chinese).Its Japanese name, tobera, comes from "tobira no ki," which roughly translates to "gate tree."This is because the plant emits an unpleasant smell when its leaves or branches are cut,so it is hung in doorways during the festival of knots,along with the heads of sardines.In English it is known as Japanese pittosporum, mock orange, Australian-laurel and Japanese cheesewood.In German, it is also known as chinesischer Klebsame ("Chinese sticky seed") or Pechsame (Pech = pitch, tar, Same = seed).In Swedish, it's called glansbuske ("glossy bush").In Brazilian Portuguese,it is known as lágrima-sabéia (“teardrops”), pau-de-incenso (“incense sticks”) or pitósporo-japonês.

Chemistry

Although not generally considered edible, P. tobira seeds have been analyzed for their nutritional content.The seed is mostly carbohydrates (71.3%), while the low fat content (5.6%) means it cannot be classified as an oil seed.A high ash content may indicate the presence of high amounts of inorganic nutrients in this plant.The total phenolic content was 102.7 mg gallic acid equivalent per gram (GAE/g),while the total flavonoid content was 31.62 mg catechin equivalent per gram dry weight (CAE/g DW).HPLC analysis revealed the presence of five phenolic acids, of which caffeic acid was the most abundant (38.57 mg/g).The next most common phenolic acids were ferulic acid (20.07 mg/g), p-coumaric acid (12.85 mg/g),cinnamic acid (5.14 mg/g) and gallic acid (1.03 mg/g). Nineteen components were found to account for 89.5% of the total essential oil content,with the highest content of oxygenated sesquiterpenes (57.5%), followed by sesquiterpene hydrocarbons (11.8%) and oxygenated monoterpenes (6.7%). Spathulenol was the most represented component (48.0%), followed by isospathulenol (5.8%), delta-elemene (4.2%), lambda-gurjunene (4.0%) and camphor (3.7%).In addition, P. tobira seed essential oil was found to have significant antioxidant activity.Methanol extract of P.tobira was found to control more than 90% of the development of rice blast, an important rice pathogen in commercial rice production, at 1,000 μg/ml.