Seaweeds of the genus Plocamium are known to produce a variety of halogenated monoterpenes. In addition to their ecological role as feeding deterrents, biological activities reported for these compounds include antibacterial, antialgal, antifungal and anticancer activities. An investigation of the non-polar extracts of the seaweed Plocamium corallorhiza resulted in the isolation of six known halogenated monoterpene compounds, 4-bromo-5-bromomethyl-1-chlorovinyl-2, 5-dichloro-methylcyclohexane (2.68), 1,4,8-tribromo-3 ,7-dichloro-3, 7-dimethyl-1,5-octadiene (2.67), 8-bromo-1 ,3,4,7-tetrachloro-3, 7-dimethyl-1,5-octadiene (2.66), 4,6-dibromo-1,1-dichloro-3,7-dimethyl-2,7-octadiene (2.64), 4,8-dibromo-1,1,7-trichloro-3,7-dimethyl-2,5-octadiene (2.65) and 3,4 ,6,7-tetrachloro-3, 7-dimethyl-1-octene (2.63) as well as eight new compounds, including five halogenated monoterpene aldehydes. The new compounds were identified by 1D and 2D NMR spectroscopic techniques as: 8-Bromo-6,7-dichloro-3,7-dimethyl-octa-2,4-dienal (2.72), 8-Bromo-1,1,2,7-tetrachloro-3,7-dimethyl-octa-3,5-diene (2.70), 4,8-Dichloro-3,7-dimethyl-octa-2,4,6-trienal (2.74), 4-Bromo-8-chloro-3, 7-di methyl-octa-2, 6-dienal (2 76), 8-Bromo-4-chloro-3, 7-dimethyl-octa-2,4 ,6-trienaI (2.75), 4-Bromo-1,3,6,7-tetrachloro-3 ,7-dimethyl-octa-1,4-diene (2.71), 8-Bromo-1,3,4,7-tetrachloro-3,7-dimethyl-octa-1,5-diene (2.69), 4,6-Dibromo-3,7 -dimethyl-octa-2,7-dienal (2.73). All compounds were screened for antimicrobial activity, brine shrimp lethality and cytotoxicity towards oesophageal cancer cells. Compound 2.68 was toxic to brine shrimp larvae at a concentration of 50 μ/mL. It also showed promising activity towards oesophageal cancer cells with an IC₅₀, of 2 μg/mL.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:rhodes/vital:3841 |
| Date | January 2005 |
| Creators | Mkwananzi, Henry Bayanda |
| Publisher | Rhodes University, Faculty of Pharmacy, Pharmacy |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis, Masters, MSc |
| Format | 90 p., pdf |
| Rights | Mkwananzi, Henry Bayanda |
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