Inhibitory effects sesquiterpenes

Matsuda H, Tadashi K, Iwao T, Hiroki U, Toshio M, Masayuki Y. Inhibitory effects of sesquiterpenes from bay leaf on nitric oxide production in lipopolysaccharide-activated... 

Kampa et al. made the interesting observation that protocatechuic acid, which is found in grapes and red wine from Vitis vimfera (Vitaceae), showed a time- and dose-dependent inhibitory effect on cell growth of T47D human breast cancer cells at low concentrations (108). The phenolic compound is a potent inhibitor of topoisomerase I (109). The plant likely contains some germanacrolides because these sesquiterpenes are known... 

Results of experiments with water and ethanol extracts from sesquiterpene-enriched plants Achillea millefolium and Gaillardia pulchella are given in Table 2. The inhibitory effects are dependent on the solvents and the concentration of plant material. Strongest effects were observed mainly, for leaves and flowers. 

The ability of feverfew extract to inhibit 5HT-secretion in platelets was used to identify compounds responsible for the inhibitory effects on platelets [44], A crude feverfew extract was separated by chromatography and fractions were screened for antisecretory activity induced by adrenaline. In five active fractions compounds were identified as the sesquiterpene lactones parthenolide (1), canin (19), artecanin (20), secotanapartholide A (24) and 3 8-hydroxyparthenolide (2). The ability of parthenolide to affect platelet activity induced by other agents was confirmed in a study of direct comparison of crude feverfew extract with parthenolide [43], Parthenolide in the micromolar concentration range inhibited platelet 5HT-secretion. 

Matsuda, H., Kagerura, T., Toguchida, I., Ueda, H., Morikawa, T. and Yoshikawa, M. (2000) Inhibitory effects of sesquiterpenes from bay leaf on nitric oxide production in lipopolysaccharide activated macrophages structure requirement and role of heat shock protein induction. Life Sciences 66(22), 2151-21 57. 

There are a number of allelochemicals among the mono-, sesqui-, and diterpenoids. In particular, plants in arid and semiarid regions produce diverse volatile terpenoids with allelopathic activity.5 Among the volatile monoterpenes, 1,8-cineole (4) and camphor (5) exhibit strong growth inhibitory effects on plants and are considered to be involved in plant competition. 1,4-Cineole (6), a minor isomer of 1,8-cineole, is a potent inhibitor of asparagine synthetase.6 -Menthane-3,8-diols (fir 7 and frw .r8), -menth-2-en-l-ols (cis 9 and trans 10), thymol (11), carvacrol (12), 1,8-cineole, cr-pinene (13), and /3-pinene (14) were isolated as allelopathic monoterpenes from Eucalyptus species.7 Eucalyptus trees also produce allelopathic sesquiterpenes including spathulenol (15), and a-, (3-, and 7-eudesmols (16-18).7... 

Three guaiane sesquiterpenes, the ester (4.13), lactaroviolin (4.3), and deterrol (4.7) showed a weak mutagenic activity in the Ames Salmonella assay (137). In addition, deterrol (4.7) exhibited moderate cytotoxicity towards Ehrlich ascitic tumor cells (EGA cells) and weak toxicity towards L1210 cells (lymphocytic leukaemia mouse) (137). Lactaroviolin (4.3) showed a weak inhibitory effect towards EGA cells, while the ester 4.13 did not impair either cell line at 50 Xg/ml (137). The Swedish authors pointed out that the greater toxicity of deterrol than of lactaroviolin was rather... 

Some empirical uses of S. sclarea suggest that its essential oil, like many essential oils of the Lamiaceae family, has an inhibitory effect on microorganisms pathogenic to man. Ulubelen et al. [51] examined the antimicrobial activity of some diterpenes and sesquiterpenes found in an acetone extract of S. sclarea. They found that 2, 3-dehydrosalvipisone, sclareol, manool, 7-oxoroyleanone, spathulenol and caryophyllene oxide were active against Staphylococcus aureus 2, 3- dehydrosalvipisone and manool were active against Candida albicans and caryophyllene oxide was active against Proteus mirabilis. 

Table 3. Inhibitory Effects of Dihydroagarofuran Sesquiterpenes on TPA-Induced EBV-EA Activation...

Plant sesquiterpenes and other terpenoids aie major detenninants of insect-plant interactions (2i 16V Many insecticidal and antifeedant terpenoids are epoxides including monoteipene Q2, 18. sesquiteipene QQ, 19-23). diteipene (Jl, 24) and triteipene derivatives (25-27) typified by the potent antifeedant azadirachtin (28-30). Most biolo cal effects have been determined with Lepidoptera and non-chrysomelid Coleoptera. Occasionally, the same compound, while normally inhibitory to herbivores, may for adapted insect species or at low concentrations have a stimulatory effect (13). Insects, in turn, synthesize their own defensive (21, and pheromonal (22) terpenoids. Plants may utilize insect pheromones such as the sesquiterpene alarm pheromone, rranj-B-famesene, in their own defense (34. 35). Inhibitory cyclic sesquiterpenes (Table I) and diterpenes (Table II) for insect herbivores have been identified from at least 28 genera of the terpenoid-rich Compositae. These studies were largely confined to extrafloral tissues. 

A special type of deterrent effect was shown by Ma (1977b). A sesquiterpene dialdehyde isolated from the warburgia plant blocks the sugar receptor cell of S. exempta for 10-20 min after two contacts of 3 min. This inhibitory effect on the sensory neuron has been correlated with a suppression of the feeding response to sucrose. Similarly, Kennedy and Halpern (1980) showed that ziziphin, a cyclic peptide alkaloid of Rhamnaceae, also temporarily inhibits the fly sugar (but not the salt) receptor. 

Encelin from Montanoa speciosa is inhibitory to growth and development of fungal cells of Mucor rouxii. Other cytotoxic sesquiterpene lactones from Montanoa tomentosa ssp. microcephala have been reported.45,46 A number of kaurane diterpenes and e/tf-kauranoids have been reported that are potentially useful because of their cytotoxicity against human tumor cells, anti-HIV activity, and trypanosomicidal activity.47 56 New structures are frequently discovered, and probably we will learn new effects in humans and animals in the future.57,58 Paradoxically, these plant natural products probably have specific and important effects in the plants, but we are still ignorant of these roles. 

---