Amri Bakhtiar

Antiviral and cytotoxic activities of some Indonesian plants

Ten methanolic extracts from eight Indonesian medicinal plants were phytochemically screened and evaluated for antiviral (HSV-1 and Poliovirus) and cytotoxic activities on murine and human cancer lines (3LL, L1210, K562, U251, DU145, MCF-7). Besides Melastoma malabathricum (Melastomataceae), the Indonesian Loranthaceae species among which Elytranthe tubaeflora, E. maingayi, E. globosa and Scurrula ferruginea exhibited attractive antiviral and cytotoxic activities. Piper aduncum (Piperaceae) was found active on Poliovirus. S. ferruginea was selected for further studies because of its activity on the U251 glioblastoma cells.

Lobarin from the Sumatran lichen, Stereocaulon halei☆

The diphenyl ether, lobarin (1) (syn. lobariol carboxylic acid) related to lobaric acid was isolated for the first time as a natural product along with five known compounds from Stereocaulon halei, a fruticose lichen collected in Indonesia. The structure of lobarin was elucidated by spectroscopic data analysis and its most stable conformers were determined by molecular mechanic dynamic calculations. A marked superoxide anion scavenging was found for compound 1 while no cytotoxicity on the B16 murine melanoma and HaCaT human keratinocyte cell lines was observed.

NMR reassignment of stictic acid isolated from a Sumatran lichen Stereocaulon montagneanum (Stereocaulaceae) with superoxide anion scavenging activities

Abstract The phytochemical study of Stereocaulon montagneanum harvested in Sumatra (Indonesia) led to the isolation of 11 known compounds including two metabolites not previously described in the genus Stereocaulon, peristictic acid (8) and menegazziaic acid (10). The complete 1H and 13C NMR spectral assignments of stictic acid derivatives are reported with some revisions. Five depsidones belonging to the stictic acid chemosyndrome were superoxide anion scavengers as potent as ascorbic acid and with no toxicity on two human cell lines.

O-glycosyl-C-glycosylflavones from Galipea trifoliata

Abstract From the stem bark of Galipea trifoliata the glycoflavones 2″- O -xylosylswertisin, 2″- O -glucosylswertisin, 2″- O -glucosylisoswertisin and 2″- O -β- d -xylosyl-8- C -β- d -galactosylapigenin were identified.

Phytochemical review of the lichen genus Stereocaulon (Fam. Stereocaulaceae) and related pharmacological activities highlighted by a focus on nine species

The Stereocaulon genus is one of the fruticose lichen groups distributed worldwide from tropical zones to polar zones. However, the scientific study of this tricky genus is still limited, making it a challenge to study the group further. Detailed morphological studies are essential to discriminate closely shaped species which is illustrated through personal data focused on phyllocladia, apothecia and spores of nine species. Secondary metabolites isolated from Stereocaulon species are mostly some depsides, depsidones, diphenylethers and dibenzofurans which can have a taxonomic value. The use of Stereocaulon lichens as a traditional medicine in several regions of the world and pharmacological studies of extracts and isolated compounds have been compiled. Biological activities as cytotoxic, anti-inflammatory, antibacterial, antifungal or antioxidant are reported.

C-glycosylflavones fromRaputia paraensis

Abstract From the stem bark of Raputia paraensis were identified schaftoside, vicenin-1 and two new compounds: 6- C -β- d -glucosyl-8- C -β- d -xylosylchrysoeriol and 6- C -xylosyl-8- C -glucosylchrysoeriol.

Crystal structure of olivetolic acid: a natural product from Cetrelia sanguinea (Schaer.)

The packing in olivetolic acid is similar to that in resorcinolic acid.

rac-Eudesm-7(11)-en-4-ol

The isolation and structural determination of rac-eudesm-7(11)-en-4-ol, C15H26O, from the steam distillate of the flowers of Dipterocarpus cornutus Dyer (Dipterocarpaceae) is described. The structure was determined from spectroscopic data and a single-crystal X-ray study. Two similar independent molecules comprise the asymmetric unit of the structure.