Stilbenoids. The stilbenoids are phenolic compounds distributed throughout the plant kingdom (Xxxxxx et al., 1995). Their functions in plants include constitutive and inducible defense mechanisms (Xxxxxx et al., 2001; Xxxxxxx et al., 2002), plant growth inhibitors and dormancy factors (Xxxxxx, 1980). Frequently, the stilbenoids are constituents of heartwood or roots, and have antifungal and antibacterial activities (Xxxxxxxx et al., 2004; Xxxxxxx et al., 2000) or they are repellent towards insects (Xxxxxx and Xxxxx, 1968). Nineteen stilbenoids have been identified in cannabis (Xxxx and XxXxxxx, 1995; Xxxxxx et al., 1980) (Figures 6-8). MeO MeO OMe Cannithrene 1 Cannithrene 2 Figure 7. Spirans from C. sativa. A, 7-hydroxy-5-methoxyindan-1-spiro-cyclohexane; B, 5-hydroxy-7- methoxyindan-1-spiro cyclohexane; C, 5,7-dihydroxyindan-1-spiro-cyclohexane. Although some studies have reported antibacterial activity for some cannabis stilbenoids (Xxxxxx et al., 1985) others have reported that the cannabis bibenzyls 3,4’-dihydroxy-5-methoxybibenzyl, 3,3’-dihydroxy-5,4’ - dimethoxybibenzyl, 3,4’-dihydroxy-5,3’-dimethoxy-5’-isoprenyl bibenzyl did not shown activity in bactericidal, estrogenic and, germination- and growth- inhibiting properties or the SINDROOM tests (a screening test for central nervous system activity) (Kettenes-van den Bosch, 1978). OH MeO OMe XX XX MeO OMe XX XX MeO Cannabispirone Iso-cannabispirone Cannabispirenone-A Cannabispirenone-B Cannabispiradienone OH MeO OH MeO MeO MeO HO HO OH OMe OH OAc OH α-Cannabispiranol β-Cannabispiranol Acetyl cannabispirol A B C Figure 8. Spirans from C. sativa. A, 7-hydroxy-5-methoxyindan-1-spiro-cyclohexane; B, 5-hydroxy-7- methoxyindan-1-spiro cyclohexane; C, 5,7-dihydroxyindan-1-spiro-cyclohexane. It has been observed that the stilbenoids show activities such as anti- inflammatory (Xxxxx et al., 2005; Xxxxx et al., 2007; Xxxxx et al., 2004), antineoplastic (Xxxxx et al., 2006; Xxxxxx et al., 1994; Xxxxxx et al., 2006), neuroprotective (Xxx et al., 2006), cardiovascular protective (Xxxxx et al., 2005; Xxxxxxx-Xxxx et al., 2006), antioxidant (Xxxxxxx et al., 2001) antimicrobial (Xxx et al., 2005), and longevity agents (Xxxxxxxxxx et al., 2005; Xxxxxxxxx et al., 2006).
Stilbenoids. Stilbenoids (1,2-diarylethenes) are another class of phenolic compounds (non flavonoids) belonging to the phenolic group and attracted great interest because of their potential health valuable effects (Xxxxxxxx et al. 2006). Stilbenes are essentially located in grape skin (Xxxxxx and Coffee 1988; Xxxxxxx and Xxxxxx-Xxxxxxx 1995) but also reported in grape seeds (Sun et al. 2006) and grape stem (Bavaresco et al. 1997). Grapes and red wine are two of the major dietary sources of stilbenes but their concentration is relatively low as compared to other phenolic compounds (Pace-Asiak et al. 1995). Grape seeds contain low amounts of stilbenes (Pezet and Xxxxxx 1996), but a substantial amount of these compounds may be found in grape stems (Sun et al. 2003). However, grape stems contribute little to these compounds in wine due to their poor diffusion property (Sun et al. 2006). Resveratrol (a monomeric stilbene) is the major stilbene of grapes. It is synthesized from phenylalanine and can exist in two isomeric forms. In wines, both isomeric forms were detected (Xxx et al. 2003) due to photochemical isomerization of trans- form into cis- form during wine making (Jeandet et al. 1995; Xxxxxxx and Xxxxxx-Xxxxxxx 1995). Stilbenes can also occur in oligomeric and polymeric forms, known as viniferins. They are induced by oxidative polymerization of monomer resveratrol through the activity of a peroxidase (Xxxx-Xxxxx et al. 2006). Many viniferins have been reported so far in grapes including ε-viniferin and δ-viniferin, dimeric resveratrol (Pezet et al. 2003; Xxxxxx et al. 2005) and α-viniferin, trimeric resveratrol (Pryce and Langcake 1977). Stilbenoids such as ampelopsin-A (dimeric resveratrol) and hopeaphenol (dimeric ampelopsin A) have also been identified (Jeandet et al. 2000; Xxxxxxxx et al. 2006). The stilbene contents in wines varied considerably due to several factors like climate, grape variety, fungal infection (Xxxxxxx et al. 2007), UV light, metal ions (Pussa et al. 2006) and enological methods (Xxxxxxx et al. 2004). It has been shown that red wine is usually more concentrated in stilbenes than rose and white wine as this depends on the skin contact of the must and the high phenolic content of grape cultivars during fermentation (Xxxxxxx et al. 2007). Many reports have been published targeted towards the quantification of stilbenes in different wines (Xxxxxx et al. 2005; Xxxxxxxx et al. 2006; Xxxxxxx et al. 2007). The medicinal and nutritional value of grapes...
