DISCUSSION
The most popular Oxytree compound is verbascoside. Verbascoside (acteoside) belongs to phenylpropanoid glycosides - a group of phenolic compounds widespread among higher plants, especially from the families:Araliaceae, Bignoniaceae, Crassulaceae, Labiateae, Oleaceae, Plantaginaceae, Polygonaceae, Scrophulariaceae, Smilaeaceae, Verbenaceae (Dembitsky, 2005; Pan et al., 2003). Its activity was assessed for both its biological and pharmacological effects. The compound is a very powerful antioxidant (Chiou et al., 2003), it also has anti-inflammatory and analgesic (Backhouse et al., 2008), immunosuppressive (Lee, 2005), immunomodulating (Akbay et al., 2002), anticancer (Abe and et al., 2001), hepatoprotective (Xiong et al., 1999) and antimicrobial (Senatore et al., 2007).
Verbascoside has numerous uses in cosmetology:
• helps to detangle tangled hair and gently cares for curly hair without irritating the hair,
• absorbs quickly into the skin and moisturizes it; cares for nails and cuticles,
• acts prophylactically against stretch marks, improves skin elasticity,
• provides remedy for swollen eyes, removes dark circles under the eyes.
Inflammation, which is the process of faster aging of tissues, including skin tissue, caused by constant exposure to factors causing inflammation is a recently noticed and investigated problem. Counteracting the progressive effects of inflammation may consist in avoiding and reducing the frequency of exposure to external factors causing inflammatory microstates, such as, for example, ultraviolet radiation, exhaust fumes, cigarette smoke, detergents, although it is not a simple task. Scientists place their hope in plants rich in certain specific glycosides, such as verbascoside, with anti-inflammatory and antioxidant effects. Such plants include: plantain leaves with the amount of 3.5% of dry weight of verbascoside, verbena herb 3.7%, 12.9% of dry leaves in the 4th stage of Sesamum indicum L., and 27,7% ofCymbaria daurica L. which is one of the highest percentages reported in plants from nature. By comparison, the content of this compound and its derivatives in leaves, twigs, flowers, and fruits of Oxytree are 9,47; 22,93; 2,31; and 17,91 mg/g DM, respectively.
In Oxytree, cistanoside F, which is also phenylpropanoid glycoside was identified. For the first time, it was isolated and its structure was determined in the herbs of Cistanche deserticola Ma. in 1985 by Kobayashi et al. The concentration of this compound in Sesamum indicum L. was 0.26%, and in lemon verbena 2%, while in Oxytree from 0.47% in twigs to 0.02% in flowers.
Cistanoside F shows vasorelaxant, and antioxidative effects, it shows a strong free radical scavenging activity on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and xanthine/xanthine oxidase (XOD) generated superoxide anion radical (O2-.). Since cistanoside F contains only one phenolic ring in the caffeoyl moiety, it has lower antioxidant activity that compounds with two aromatic rings. The highest content of this compound: 4.28 mg / g DM was found in twigs, less 1.92 mg / g in fruit and 1.22 mg / g in leaves, and the least 0.54 mg / g DM in Oxytree flowers.
Clerodendrin is used in the manufacture of a medicament for the treatment of degenerative changes in the retina. Clerodendrin showed a hypotensive activity in the rat by measurement of the tail volume pressure in preliminary pharmacological tests. This compound belongs to the flavone glycosides with the structure of apigenin7-O -digiucuronide and for the first time has been isolated from the leaves of Clerodendron trichotomum Thunb. To obtain this compound from Scutellaria barbata and Glechoma longituba (Nakai) Kupr. is possible. A method for producing clerodendrin isolated from Clerodendron trichotomum Folium and a pharmaceutical composition containing the above compound for the prevention and treatment of gastritis and reflux esophagitis, has been patented (PCT/KR2003/001037). Clerodendrin was identified in trace amounts, while other flavonoids: apigenin glucuronide, apigenin-7-O-glucuronopyranosyl(1→2)-glucuronopyranoside and luteolin-diglucuronide were in total determined in small amounts only in leaves and flowers: 1,61 and 1,99 mg/g DM.
The third and last group of phenolic compounds described in Oxytree are the iridoids. The representative of this group with the highest concentration is catalpol - simply monoterpene with a glucose molecule attached. It was primarily obtained from the root of Rehmannia glutinosa Libosch. (1-10% depending on the variety) and also was isolated from the Cymbaria daurica L. (11.4%), Plantago lanceolate , Buddleia species, Radix scrophulariae andLancea tibetica . Pharmacological effects include analgesic, sedative, hepatoprotective, laxative, anti-inflammatory, antibacterial, anti-tumor and anti-apoptotic effects. In Oxytree, this compound is present in all examined morphological parts, i.e. in leaves, twigs, flowers, and fruits, in a concentration: 0,65; 9,96; 3,08 and 7,36 mg/g DM.
Another iridoid is 7-hydroxytomentoside, about which there is very little information in the literature. It was first isolated fromPaulownia tomentosa and described in 1993 by Damtoft and Jensen (1993). It was then isolated from Paulownia coreana Uyeki leaves. The 7-hydroxytomentoside has anti-inflammatory effects on skin with irritations, atopy and acne. It is used to lighten the skin and reduce the signs of aging. From all the morphological parts of Oxytree, 7-hydroxytomentoside is found only in leaves at a rate of 6 mg/g DM.
Even if the concentrations of the described compounds in Oxytree are not spectacular, yet due to the fact that the number of leaves, twigs and even flowers on the trees is so high and the tree density in the plantation is 600 pcs/ha, they can be an excellent source of biologically active natural phytochemicals used in medicine and cosmetology.
Its high calorific value makes Oxytree a good raw material to be used as a renewable carbon source. This species is ideal for establishing commercial forests.