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Biomedical subjects

S Mavi

Publications and source records attributed to S Mavi.

7 recordsLinked to original sources

Xanthones from Hypericum roeperanum.

Four new xanthones have been isolated from the roots of Hypericum roeperanum. Their structures have been established by a combination of spectroscopic and chemical methods as 1,6-dihydroxy-5-methoxy-4',5'-dihydro-4',4',5'-trimethylfurano- (2',3':3,4)-xanthone (5-O-methyl-2-deprenylrheediaxanthone B), 1,6-dihydroxy-5-methoxy-6',6'-dimethylpyrano-(2',3':3,4)-xanthone (5-O-methylisojacareubin), 1,3,5,6-tetrahydroxy-2-(2',2'-dimethyl-4'-isopropenyl)-cyclopen tanylxanthone (5-O-demethylpaxanthonin) and 1,3,5,6-tetrahydroxy-4-trans-sesquilavandulylxanthone (roeperanone). In addition, 2-hydroxyxanthone, 5-hydroxy-2-methoxyxanthone, 1,5-dihydroxy-2-methoxyxanthone, 2-deprenyl rheediaxanthone B, isojacareubin and calycinoxanthone D have been isolated and characterized. Some of the isolated xanthones exhibited antifungal activity against Candida albicans.

Antifungal Agents↗

Antifungal and antibacterial chalcones from Myrica serrata.

The dichloromethane extract of the leaves of Myrica serrata inhibits growth of Cladosporium cucumerinum, Bacillus subtilis, and Escherichia coli on TLC plates. Activity-guided fractionation led the isolation of 2',4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone (1), 2',4'-dihydroxy-6'-methoxy-5'-methylchalcone (aurentiacin A) (2), 2',6'-dihydroxy-4'-methoxy-3',5'-dimethyldihydrochalcone (3), 2'-hydroxy-4',6'-dimethoxy-3'-methyldihydrochalcone (4), and 2', 6'-dihydroxy-4'-methoxy-3'-methyldihydrochalcone (5). In addition, the flavanones demethoxymatteucinol (6) and cryptostrobin (7) were also identified.

Anti-Bacterial Agents↗

Larvicidal constituents of Melantheria albinervia.

Bioactivity-guided fractionation has led to the isolation of two larvicidal diterpenes, active against the yellow fever-transmitting mosquito Aedes aegypti, from a dichloromethane root extract of Melantheria albinervia (Asteraceae), a plant from Zimbabwe. These diterpenes were identified as ent-kaur-16-en-19-oic acid and 9(11),16-kauradien-19-oic acid. The diterpenes were also weakly active against Bacillus subtilis.

Aedes↗

Antimicrobial activity of essential oil from Hoslundia opposita.

The essential oil from the leaves of Hoslundia opposite was extracted by hydrodistillation. GC/MS analysis of the volatile oil showed that it contains largely the sesquiterpenes and sesquiterpene alcohols. The essential oil was tested against eight different bacterial species and one fungal species. The antibacterial and antifungal properties of the essential oil from Hoslundia opposite were determined by using seeded agar plates with wells into which was placed the oil, and flasks of yeast extract and sucrose broth for mycelial growth of Aspergillus niger. After incubation for 24 hours, the diameter of the inhibition zone was measured for the antibacterial tests and after seven days, the dry weight of the mycelia was measured and a percentage of inhibition calculated using controls where no samples were added. The results obtained showed that the essential oil from this plant has significant activity against Aspergillus niger, Acinetobacter calcoacetica, Brochothrix thermosphacta and Flavobacterium suaveolens. These were most affected by the volatile oil from Hoslundia opposita.

Bacteria↗

Indigenous plant remedies in Zimbabwe.

Two household surveys undertaken in Zimbabwe between 1981 and 1983 revealed extensive use of indigenous plant remedies in the home-management of childhood diarrhoea and many adult illnesses. Names of the local plants, trees and shrubs are listed, together with the part of the plant used and the type of condition treated. The usage of medicinal plants underscores the need for further study of indigenous pharmacopoeias and the therapeutic properties of plants. The role of indigenous plant remedies within local health care systems is also worthy of closer investigation.

Diarrhea↗